AVSF 1 Lab Manual PDF

DIAGNOSTIC PROCEDURES FOR ASSESSING ACCOMMODATION The four most common types of accommodative dysfunctions are insufficiency, excess, infacility and illsustained accommodation. The testing to follow will probe these four areas. ACCOMMODATIVE AMPLITUDE PURPOSE • To determine the patient's maximum acc...

DIAGNOSTIC PROCEDURES FOR ASSESSING ACCOMMODATION The four most common types of accommodative dysfunctions are insufficiency, excess, infacility and illsustained accommodation. The testing to follow will probe these four areas. ACCOMMODATIVE AMPLITUDE PURPOSE • To determine the patient's maximum accommodative amplitude, the dioptric distance between the far point and near-point of accommodation. • To determine whether the patient has sufficient amplitude of accommodation to afford a clear image of reading material at the normal or desired reading distance. MINUS LENS METHOD FOR MEASURING THE AMPLITUDE OF ACCOMMODATION (NOT PRACTICED IN LAB) MATERIALS • Either Phoropter or loose lens racks and Distance Rx • Appropriate near-point card (not a small Hart chart) • Occluder or patch PROCEDURE • Set Up o Patient is seated with good posture either behind the phoropter viewing through his distance Rx or in free space wearing his distance Rx. o A well-illuminated near target (one line of letters larger than the patient's near visual acuity) is set at 40 centimeters (20/25 is a ½ line). • Testing is done monocularly only. To perform this procedure binocularly would only assess positive relative accommodation (PRA). • Patient Instructions: "I’m testing to see the maximum amount focusing your eyes can do. Try to get the letters clear each time I change the lens in front of your eye. Tell me when the letters are slightly blurred, but still readable, and you cannot make them clear." • Minus lenses are added in 0.25 D increments. When the patient reports first sustained blur, the end point has been reached and lens power is noted. RECORDING • Method ("Minus Lens") and use of Phoropter or Lens Rack • Near point card and size of print used • Total of minus lens power to first sustained blur from Distance Rx o To obtain the amplitude in diopters, add -2.50 diopters for working distance to the amount of minus added. ▪ Minus Added until first sustained blur 6.00 D ▪ Working distance 2.50 D ▪ Accommodative Amplitude 8.50 D • Time taken to clear successive increments of minus (rapid or sluggish?) • Any asthenopia reported 47 All material contained in this manual is copyrighted. Please do not reproduce or distribute. PUSH-UP TECHNIQUE FOR AMPLITUDE OF ACCOMMODATION MATERIALS • Appropriate near-point card (not a small Hart chart) • Phoropter or patient's distance Rx • Occluder or patch PROCEDURE: • Set Up o Patient is seated with good posture either behind the phoropter viewing through his distance Rx or in free space wearing his distance Rx. o With good illumination a target line of letters one level above the best corrected VA is held directly in front of the eye to be tested. • Test monocularly only. • Patient Instructions: "I am going to move this card toward you. Tell me when you can no longer read the letters." • Move the near-point card toward the patient at a rate of approximately one inch per two seconds, until the patient reports blurred letters that won’t clear up. To facilitate a correct answer, the patient can be asked to read the letters as you get closer. Once they start to respond incorrectly, the end-point has been reached. • Note the distance from the patient at which the patient can no longer identify the letters and then convert into diopters. RECORDING • Method ("Push-up method") • Near point card and size of print used • Linear distance of first sustained blur (inches or centimeters. Centimeters are easier.) • Dioptric measurement o If you measured in inches: divide 40 by the number of inches to obtain diopters. ▪ First sustained blur at 8": 40/8 = 5.00 D =Amplitude of Accommodation. o If you measured in centimeters: divide 1/meters ▪ First sustained blur at 20cm: 1/0.20 meters=5.00D Amplitude of Accommodation • Any postural changes noted, (backing away, etc.) • Any patient discomfort observed, and when it occurs PULL-AWAY TECHNIQUE FOR AMPLITUDE OF ACCOMMODATION MATERIALS • Appropriate near-point card (not a small Hart chart) • Phoropter or patient's distance Rx • Occluder or patch PROCEDURE: • Set Up o Patient is seated with good posture either behind the phoropter viewing through his distance Rx or in free space wearing his distance Rx. o With good illumination a target line of letters one level above the best corrected VA is held directly in front of the eye to be tested. 48 All material contained in this manual is copyrighted. Please do not reproduce or distribute. • • • • Test monocularly only. Patient Instructions: "I am going to move this card away from you. Tell me when you can first read the letters." Move the near-point card away from the patient at a rate of approximately one inch per two seconds, until the patient reports being able to read the letters. Ask the patient to read. Note the distance from the patient at which the patient first reads and convert into diopters. RECORDING • Method ("Pull away method") • Near point card and size of print used • Linear distance of first ability to read the letters (inches or centimeters. Centimeters are easier.) • Dioptric measurement o If you measured in inches: divide 40 by the number of inches to obtain diopters. ▪ First sustained blur at 8": 40/8 = 5.00 D =Amplitude of Accommodation. o If you measured in centimeters: divide 1/meters ▪ First sustained blur at 20cm: 1/0.20 meters=5.00D Amplitude of Accommodation • Any postural changes noted, (backing away, etc.) • Any patient discomfort observed, and when it occurs Norms for Minimum Amplitude of Accommodation • • Hoffstetter: 15-0.25X(age in years) Donders: Age (years) 10 15 20 25 30 35 40 45 50 55 60 70 75 Amplitude (diopters) 14.00 12.00 10.00 8.50 7.00 5.50 4.50 3.50 2.50 1.75 1.00 0.25 0.00 49 All material contained in this manual is copyrighted. Please do not reproduce or distribute. ACCOMMODATIVE FACILITY PURPOSE • To monocularly and binocularly determine the patient's ability to make rapid and accurate step changes in accommodation. MATERIALS • Patch or occluder • Near-point card • +/-2.00 lens flippers for patients under the age of 30 years. • +/-1.50 lens flippers for patients from 30-39 years of age. • Suppression control for binocular testing: o Polaroid glasses and the Acuity Suppression #9 vectogram, or o A pen or pick-up stick. PROCEDURE • Set Up o Patient is seated with good posture wearing his distance Rx. o A well-illuminated near target, one line above best VA is placed at 40 centimeters. o Monocular: one eye is occluded. o Binocular: occlusion is not used. o The test is performed the best corrected distance Rx. • Test OU then OD and OS. • Patient Instructions: "Look at these letters. I'm going to put lenses in front of your eye and I want you to tell me as soon as the print becomes as clear as it is without any lens. I'm going to time you for one minute. Ready, set, go." • The minus lens is placed in front of the patient's eye until the letters are reported as clear or 5 seconds elapses. Then flip the lenses so that the plus lens is placed in front of the patient's eye until the letters are reported as clear or 5 seconds elapses. Continue in this manner, alternately flipping the +/- lenses for one minute. • Count the total number of cycles (i.e., two flips) the patient can clear in one minute. • If the examiner is uncertain as to whether the patient is really clearing the print, the patient is asked to read the letters or numbers aloud. • Suppression controls of binocular facility o Acuity Suppression Vectogram #9 ▪ This method utilizes a polarized vectogram instead of the near point card. Make the patient aware that, while wearing the polarized Rx, line six is visible to the left eye, while line four is visible to the right eye. Instruct him to report if the letters on either line disappear at any time. o Physiological diplopia ▪ A pen or pick-up stick held between the acuity card and the patient is used to monitor suppression. Instruct the patient to report to you if one of the pens (or sticks) ever disappears while they are looking at the letters. • Patient instructions: "We are going to do the same thing again, but this time with both eyes. I'm going to put lenses in front of your eyes and I want you to tell me as soon as the print becomes as clear as it is without any lens. I'm going to time you for one minute. Also, tell me if one of the lines (pens or sticks) disappears at any time or if you see double letters. Ready, set, goes." 50 All material contained in this manual is copyrighted. Please do not reproduce or distribute. RECORDING • • • • • • • • • • Type of near point card and size of print used. Number of cycles per minute (CPM). Failure of or degree of difficulty in, clearing plus or minus lenses. Delays in initially clearing plus or minus lenses. Whether performance deteriorates as the test progresses (indicates ill-sustained accommodation) Note: Postural changes, attempts on the part of the patient to pull the card closer or move it further away, squinting, asthenopic complaints Any size changes reported by the patient (SILO) Note any diplopia or suppression. If patient is unable to perform task, consider recording seconds to clear plus/minus. Examples for the Monocular and Binocular Phases: o +/- 2.00: OD, 13 CPM; OS, 13 CPM; OU, can't clear (-), but clears (+) in 1-2 seconds. o +/-2.00: OD 10 CPM; OS 5 CPM; attempts to pull card in with minus, OD and OS; OU 5 CPM, (+) is harder to clear, intermittent suppression OS. Claud Worth G. N. Getman A.M. Skeffington, OD Walter Rudolph Hess Merton C. Flom Walter Lancaster Bruno Bagolini 51 All material contained in this manual is copyrighted. Please do not reproduce or distribute. CLINIC PASS/FAIL CRITERIA, ACCOMMODATIVE FACILITY TESTING Expecteds for accommodative facility Monocular Binocular +/-2.00 (patients under 30 years) 11 CPM 8 CPM +/-1.50 (patients from 30-39 years) 10 CPM 8 CPM Table of expected for accommodative testing Test AMPLITUDE OF ACCOMMODATION Push-up amplitudes Minus lens test MONOCULAR ACCOMMODATIVE FACILITY Children (+/-2.00 calling out targets) 6 years old 7 years old 8-12 years old Adults (+/-2.00 saying when targets are clear) 13-30 years old 30-40 years old Expected finding Standard Deviation 18-1/3 age 2 diopters < push up +/-2.00 diopters 5.5 cpm 6.5 cpm 7.0 cpm +/-2.5 cpm +/-2.00 cpm +/- 2.5 cpm 11.00 +/-5.00 cpm Not available BINOCULAR ACCOMMODATIVE FACILITY Children (+/-2.00 calling out targets) 6 years old 7 years old 8-12 years old Adults (Use powers based on amps) 3.0 cpm 3.5 cpm 5.0 cpm 10.0 cpm +/-2.5 cpm +/-2.5 cpm +/-2.5 cpm +/-5.00 cpm MEM Retinoscopy Fused cross cylinder Negative relative accommodation (NRA) Positive relative accommodation (PRA) +0.50 diopters +0.50 diopters +2.00 diopters -2.37 diopters +/-0.25 diopters +/-0.50 diopters +/-0.50 diopters +/-1.00 diopters 52 All material contained in this manual is copyrighted. Please do not reproduce or distribute. FUSED CROSS CYLINDER (NOT PRACTICED IN LAB) PURPOSE • To evaluate the lead or lag of accommodation. • To select a tentative near point lens prescription through which to perform near-point testing See Rosenfield, M; First Year Optometry: Laboratory Manual, Revised August 1993. NRA/PRA (NOT PRACTICED IN LAB) PURPOSE • To measure flexibility between accommodation and convergence. • To determine the range of clear vision at near point and to help determine an appropriate near Rx. See Rosenfield, M; First Year Optometry Laboratory Manual, Revised August 1993. NEAR POINT RETINOSCOPIES There are four primary types of near point retinoscopy: MEM, Book, Bell, and Stress-point. The first two will be practiced in lab. The last two are note in the Lab Appendix for your reference. MEM RETINOSCOPY (MONOCULAR ESTIMATE METHOD) PURPOSE • To objectively determine a patient's accommodative posture or lag of accommodation while engaged in a task requiring moderate identification or reading grade appropriate words. • To determine an appropriate near vision Rx. MATERIALS • Appropriate Rx (habitual or proposed NV Rx). • Retinoscope (preferably spot although streak is fine). • Appropriate MEM graded cards (preschool to adult) and card holder affixed to retinoscope • Loose lenses (-0.50, +0.50, +0.75, +1.00, +1.25. etc.) PROCEDURE • Set-Up o Patient is out of the phoropter, initially wearing his distance prescription. o After the initial assessment, the tentative near add should be evaluated. o Examiner sits opposite the patient at eye level, with the target at the patient's Harmon distance (unless some other working distance is more appropriate). o Lighting should be normal room illumination unless it needs to be dimmed to see the patient’s retinoscopy reflex. 53 All material contained in this manual is copyrighted. Please do not reproduce or distribute. • Select the appropriate MEM card corresponding to the grade or reading level closest to that of the patient. Card selected can be low demand (large print) or high demand (small print). • Patient Instructions: "With both eyes open, read the words on the card aloud." • Make a single sweep with the retinoscope, (i.e., not the usual scoping motion) observing the center of the retinoscopic reflex, and note whether there is "with" or "against" motion for the eye being tested. • Quickly place a lens before the eye you are scoping to estimate the lag/lead of accommodation. Repeat for the other eye. • IMPORTANT NOTE: DO NOT hold the lens in front of an eye for greater than 1/5 of a second because the eye will have time to accommodate to the lens and/or binocularity may be disrupted. RECORDING • The power of the neutralizing lens used for each eye, including any astigmatism and its meridian. • Fluctuations or instabilities in the reflexes • Rx used • Reading level on MEM card used • Harmon distance (per individual) or other. RESULTS • Expecteds: Normal lag of accommodation is between +0.25 to +0.75 D. • Findings that are outside the expected range are suggestive of an accommodative or functional vision disorder. o Unequal reflexes. o A lag greater than +0.75. o Any against motion (excess accommodation). 54 All material contained in this manual is copyrighted. Please do not reproduce or distribute. BOOK RETINOSCOPY (Cognitive Retinoscopy) PURPOSE • To probe the patient's accommodative system, binocularity, ability to sustain, interest, attention and information-processing ability while the patient is performing a reading task. • To clinically determine the effect of lenses on reading comprehension and the developmental stages of the above listed functions. MATERIALS • Retinoscope (preferably spot type) • Yardstick • Probe lenses (equal plus or minus spheres used BINOCULARLY) • Target o Gray Oral Reading Paragraphs o Good Night Moon (a pre-school picture book with higher cognitive demand). o If necessary, any age appropriate text. • Appropriate Rx (usually distance habitual or proposed NV Rx) PROCEDURE • Set-Up o Standard room illumination. o Patient is out of the phoropter, wearing the appropriate Rx, and seated with his head above the level of the examiner. o The retinoscope is held slightly above the plane of the book at patient's habitual working distance or the Harmon distance • Pick out the Gray Oral Reading Paragraph, which corresponds to two grades below the patient's actual grade level. • Ask the patient to read aloud. If excessive difficulty is demonstrated, go to the next lower grade level, until reading is done without difficulty. The patient is then instructed to read silently. • Each eye is scoped successively, and the type of motion, color, and brightness of the reflex is observed. • "Probe" lenses are placed in front of both eyes, not to neutralize the motion but, to see the effect of these lenses on motion, color, brightness and flexibility of the reflex, as well as the patient's working distance. • Observe characteristics such as: frequency of visual errors, sight vocabulary errors, comprehension, phonetic attack, anticipatory skills, reading rate, and persistence at task. RECORDING • Grade level of reading material used for the testing. • Distance at which the reading material is initially held vs. Harmon Working Distance. • Initial type of motion, the estimated amount, color of reflex, brightness of reflex and interpretation. • Probe lenses used. • Effect of probe lenses on motion, color, brightness of reflex, and on the reading distance. • Flexibility (fluctuations) of reflex response. 55 All material contained in this manual is copyrighted. Please do not reproduce or distribute. RESULTS • Combination of: low against motion, bright reflex, bright pink or white color: o Comprehension takes substantial mental effort. o Interest in material is high. o Instructional (patient is reading to learn). • Combination of: neutral to low with motion, flexible, bright reflex, pink color: o Material is easy. o Comprehension takes little effort. o Interest might be low. • Combination of: high "with" motion, dulling of reflex, brick-red color: o Material is too difficult to comprehend. o No meaning obtained. o Frustration level reached. o Lack of interest in the task. iii. Bell Retinoscopy: See Appendix iv. Stress Point Retinoscopy: See Appendix 56 All material contained in this manual is copyrighted. Please do not reproduce or distribute. STANDARDIZED ORAL READING PARAGRAPHS by WILLIAM S. GRAY Grade 1 Grade 2 Once there was a little pig. He lived with his mother in a pen. One day he saw his four feet. "Mother," he said, "what can I do with my feet?" His mother said, "You can run with them." So the little pig ran round and round the pen. the woods. r the dog. og to go home. ld not go home. d, me without my dog." gan to cry. Grade 5 interesting birds in my bird-room amed Jackie. usiness from t, scarcely ever n stolen from a he could fly, and red in a house long een given to me as a Grade 9 mately six feet tall and ll proportioned. His ned to be florid; his and remarkably far on of hair covered the as scrupulously neat in and, although he s tent early, he was Grade 3 Once there was a cat and a mouse. They lived in the same house. The cat bit off the mouse's tail "Pray puss," said the mouse, "give me my long tail again." "No," said the cat, "I will not give you your tail till you bring me some milk." Grade 6 Grade 7 The part of farming enjoyed most by a boy is the making of maple sugar. It is better than blackberrying and almost as good as fishing. One reason why a boy likes this work is that someone else does most of it. It is a sort of work in which he can appear to be very industrious and yet do but little. It was one of those wonderful evenings such as are found only in this magnificent region. The sun had sunk behind the mountains, but it was still light. The pretty twilight glow embraced a third of the sky, and against its brilliancy stood the dull white masses of the mountains in evident contrast. Grade 10 Grade 11 Responding to the impulse of habit Joseph spoke as of old. The others listened attentively but in grim and contemptuous silence. He spoke at length, continuously, persistently, and ingratiatingly. Finally exhausted through loss of strength he hesitated. As always happens in such exigencies he was lost. Grade 4 Once there lived a king and a qu large palace. But the king and q were not happy. There were no children in the house or garden. they found a poor little boy and their door. They took them into beautiful palace and made them own. The king and queen were happy. Grade 8 The crown and glory of a useful character. It is the noblest poss man. It forms a rank in itself, an the general good will, dignifying station and exalting every positi society. It exercises a greater po than wealth, and is a valuable m securing honor. The attraction of the American prairies as well as of the alluvial deposits of Egypt have been overcome by the azure skies of Italy and the antiquities of Roman architecture. My delight in the antique and my fondness for architectural and archaeological studies verges onto a fanaticism. 57 All material contained in this manual is copyrighted. Please do not reproduce or distribute. KEY ELEMENTS FOR NEAR POINT RETINOSCOPIES Target Circle of 20/50 letters held at the retinoscope Card with appropriate sized targets with hole for retinoscope Wolff wand with silver sphere Working Distance Desirable Response 20” +0.50 to +0.75 over distance Rx Patient’s habitual near working distance Neutral to +0.25; both eyes equal 20” Stresspoint phenomenon 4” closer than Harmon distance for children; 6” closer for adults Initial “with” motion; change to against motion 18” from patient; return to “against” motion 19” from patient; Both eyes equal Wolff wand with silver sphere 20” Gray oral reading paragraph of appropriate level Patient’s habitual near working distance With grade-level material, a bright, pink full reflex varying from +0.50 to plano to -0.50; both eyes equal 7”-10” Varying against motion (range of -0.25 to -1.50) when searching for the mouse; release to plano when child regards the retinoscope Goodnight Moon picture book In phoropter? Use of lenses Scoping on axis Ages Respo immedi of l Yes Patient wears lenses OU throughout measurement On-axis when patient reads letters around the card opening 5 yrs and up Initial “ mo neut No Trial lenses used monocularly and introduced briefly in front of patient’s eye On-axis when patient reads letters around the card opening 3-5 yrs and up Initia motion No Measurement repeated with OU probe lenses; Flipper lenses of equal spheres work best Not critical; you are not observing reflex motion Infant to adult Stress near Ha moves c equal l No Measurement repeated with OU probe lenses; Flipper lenses of equal spheres work best On-axis when you keep the sphere in your line of sight and the patient’s simultaneously Infant To adult Shift to is farth with pro No Measurement repeated with OU probe lenses; Flipper lenses of equal spheres work best Most on-axis when patients reads the top sentence 5 yrs to adult No Motion is estimated. Lenses rarely used. Equal sphere flippers can be used if desired Most on-axis when child reaches for the mouse near your retinoscope 2-5 yrs 58 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Initial w so that move ba find n Neutra with e Initia motion and sea neutra equal pl THERAPY TECHNIQUES FOR FIXATION, PURSUIT AND SACCADES Groffman tracing • Purpose: o To improve the speed and accuracy of multiple small-angle saccadic and/or pursuit ocular motility. • Equipment: o Chalkboard, paper or computer (as available). • Set-up and instructions: o May be performed monocularly, biocularly or binocularly o Patient views the Groffman tracing on paper, on the chalkboard or on the computer. Lines connect targets at the left of the screen to targets at the right. • Recommended patient instructions o “Start at the ____ and follow the line to see what it connects to. Keep your head still. Don’t use your fingers!”” • Comments o Loading can be added (often called distracters) ▪ Number/letter counting (cognitive distracters) ▪ Balance board ▪ Bean bag o Inter-sensory integration ▪ Metronome o Visual-Motor support ▪ Flashlight ▪ Pointer stick o Motor-Overflow Control ---watch for: ▪ Head movements ▪ Improper motor responses (arms, legs, body) Flashlight tag • Purpose: to improve the accuracy, smoothness, and speed of pursuit ocular motility while minimizing head movements. • Equipment: o Two flashlights with spot focus ability are needed to perform the flashlight chase o Eye patch for monocular training. o A red filter is needed for one flashlight and a green filter for the other. (optional) • Set-up and instructions: o Depending on the case train binocularly or monocularly. o When using two flashlights place colored acetate over one or both flashlights to help patient identify his lights vs. the doctor’s. Move one flashlight randomly, putting the spot of light on walls or on the ceiling. The patient attempts to place his spot on yours and follow your moving spot. o Training can be accomplished binocularly when pursuit skills are adequate for each eye. o Red-green filters may be used to train anti-suppression while performing pursuits. Place a red filter on one flashlight and a green filter on the other while the patient wears red/green glasses. 59 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Recommended patient instructions o o o • “Try to put your flashlight spot on mine and move it to follow mine.” “Put on the red and green glasses. Try to keep a single spot and follow it. Tell me whether you see one spot or two spots, one red and the other green. The red and green spots will be a combination color when you have your spot exactly on mine.” “Now you hold the flashlight with the red spot and I’ll hold the flashlight with the green spot. Try to follow my green spot while keeping your red spot exactly on mine.” Comments: o Can be performed under monocular, bi-ocular (with red-green glasses), or binocular viewing conditions. o Loading ▪ Balance board ▪ Bean bag ▪ Number/letter counting ▪ Other o Inter-sensory integration ▪ Metronome o Visual-motor integration ▪ Built in visual-motor support o Bimanual integration ▪ Uses 2 flashlights ▪ Can be monocular, bi-ocular or binocular o Overflow Control----watch for: ▪ Head movements ▪ Improper motor responses (arms, legs, body) 60 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Marsden Ball • Purpose o To improve accuracy and smoothness of pursuits while minimizing head movements. • Equipment o Marsden ball which is suspended from the ceiling. o Eye patch if performing monocular training. o Bunting stick. • Set-up and instructions o Have your patient patch one eye and stand in front of the ball (approximately 1 m away). o Place the ball at the patient’s eye level. o Make the Marsden ball swing laterally and have the patient track it while you observe the eye movements. o Give your patient feedback about inaccuracies and head movements. Motor support can be added if there is difficulty; have your patient point to the target being tracked. o Have your patient track with the other eye and then binocularly. (OD, OS, OU) o Observe your patient’s performance with each eye and binocularly in terms of accuracy, smoothness, speed, head movement and posture. • Recommended patient instructions o “Let the ball swing back and forth in front of you. Your job is to follow the ball with your eye(s). Try to keep your head still.” o “Please keep following the swinging ball with your head motionless and try to count backward from 100 by threes (100, 97, 94, 91, 88, etc.). Let’s try counting backward by twos (100, 98, 96, etc.), as this may be easier for you.” o “Let’s repeat that exercise but do it standing on one foot.” • Comments o May be performed under monocular or binocular viewing conditions. o Loading ▪ Number/letter counting ▪ Balance board o Inter-sensory integration ▪ Metronome o Visual-motor integration and support ▪ Perform with eyes alone (provides no motor support) ▪ Use a bunting stick ▪ Stand on one foot to minimize somato-sensory support Keystone Rotator • Purpose: to improve the accuracy, smoothness, and speed of pursuit ocular motility, while minimizing head movement. • Equipment: o the standing/keystone rotator o an eye patch for initial monocular training o flashlight o pointer/stick o metronome • Set-up and instructions: o Have your patient view a moving target, such as a sticker, on the face of the rotating 61 All material contained in this manual is copyrighted. Please do not reproduce or distribute. disk. Observe the pursuit movements for accuracy, smoothness, and head movements. Have the patient point to the moving target, if necessary, for motoric hand support. Switch the patch to the other eye and repeat the training. (OD, OS, OU) When each eye has achieved a sufficient skill level, have your patient view the rotator binocularly. Red-green filters, in spectacles, can also be added or monitoring suppression and for appreciating the depth effect created by any of the rotating eccentric circles. o Have the patient try to maintain good following movements while asking questions, such as spelling his name, count numbers backward from 10 to 1, or solve simple mathematic problems. Recommended patient instructions o “Follow the sticker target as smoothly as is possible.” o “Keep your head as still as possible.” o “Wear the red-green glasses and watch the eccentric circles and notice whether the center floats closer or moves farther away.” o “Notice whether the red or green portion disappears, indicating suppression.” Comments: o May be performed under monocular or binocular viewing conditions. o Loading ▪ Number/letter counting ▪ Balance board ▪ Bean bag o Inter-sensory integration ▪ Metronome o Visual-motor integration and support ▪ Eyes alone (rarely done) ▪ Flashlight ▪ Pointer stick o o o • • Pegboard rotator • Purpose: o To improve the speed and accuracy of pursuit ocular motility. o To develop eye-hand coordination under static conditions with saccadic eye movements or dynamic conditions with pursuit eye movements. Visual sequencing and spatial concepts may be included. • Equipment: o Rotating Peg Board Trainer o Eye patch (optional) o Golf tees or pegs • Set-up and instructions: o Patient should either be standing or sitting at a reasonable distance. o Begin with a static task (rotator on speed zero) and the concentric squares disk. o Determine the static fill time by recording the time it takes to place all the pegs in the disk. o Repeat the task by increasing the speed to 5; repeat again at maximum speed (10). o Repeat the task by rotating counterclockwise. • Recommended patient instructions: o “Place the peg in the correct hole to make the proper pattern” o “Hold the peg over the hole as the disk rotates and insert it when the hole is at the top” 62 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Comments: o o o o Can be performed under monocular or binocular viewing conditions. Visual-motor integration ▪ Built in visual-motor support Organization ▪ Must follow a specific pattern ▪ Can place the pegs in the holes at will or better yet… ▪ Circle around placement hole for 1-2 revolutions before placement. Guidelines: ▪ To stimulate interest and cognitive processing, the rotator disk can be filled with the pegs in a variety of sequences. For example, your patient can begin with the four corners, working your way toward the center. Place the first peg in the upper right corner, then the upper left, then the lower left, and then the lower right. Now return to the upper right and place another peg next to it and repeat the sequence. ▪ To aid localization, tell your patient to begin by hovering over the hole into which he is going to place the peg for one revolution (360 degrees) and then touch down. The act of inserting the peg in the hole only at a specific point will be difficult initially if he is impulsive. ▪ This procedure can be done with a patch over one eye to compare the performance of each eye and then both eyes together Homework • All of the above techniques may be performed at home if the materials are available. • Other home techniques (ones marked with asterisks are both for training saccades and pursuits) include: o Line design books* o Pencil and paper Groffman tracing* o Pencil and paper Geo shapes* Four corner saccades • Purpose: saccadic and fixation therapy to increase speed and accuracy for large- and moderateangle saccades. • Equipment: o Appropriate wall targets o Flashlight o Eye patch (optional) • Set-up and instructions: o Patient should be standing. o Attach numbered cards (1-4) or hart chart quadrants to the wall in a square pattern. o Have the patient look at the first target for 3-5 seconds, and then saccade to the second target, then the third then the fourth. This is one cycle which may be repeated as often as appropriate. o Use a flashlight or laser to help determine where the patient is looking and to promote inter-sensory integration. 63 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Comments: o o o May be performed under monocular, bi-ocular (with red-green glasses), or binocular viewing conditions. Loading ▪ Balance board ▪ Bean bag ▪ Number/letter counting Inter-sensory integration ▪ Metronome Chalkboard saccades • Purpose: saccadic and fixation therapy to increase speed and accuracy for large- and moderateangle saccades. • Equipment: o Chalkboard and chalk. o Eye patch (optional). o Flashlight or laser. o Pointer stick (optional) • Set-up and instructions: o Draw a regular or confusing pattern of targets on the chalkboard (will be demonstrated in lab) such as vertical rows of numbers or letters. Ask the patient to read the numbers aloud as he shifts his gaze from one target to another. o Can add a flashlight or laser to the task to confirm fixation. • Comments: o Monocular or binocular viewing conditions. o Loading ▪ Balance board ▪ Bean bag ▪ Number/letter counting o Inter-sensory integration ▪ Metronome o Visual-motor integration and support ▪ Eyes alone (rarely done) ▪ Flashlight ▪ Pointer stick ▪ Bimanual integration • 2 flashlights • 2 pointers, etc. o Change the arrangements of letters or numbers ▪ Vertical patterns ▪ Circular patterns ▪ Star patterns ▪ Irregular 64 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Hart chart saccades • • • • • Purpose: saccadic and fixation therapy to increase the speed and accuracy of fixation when performing large, moderate, and small-angle saccades, as well as reading-related eye movements. Equipment: o Large Hart Chart o Eye patch (optional) Set-up and instructions: o Tape the large chart to a wall. Be sure that there is good lighting on the chart. o Put a patch over one eye if the task is to be done monocularly. o Say, “Read aloud the first letter and last letter of each line (O-E, Y-X, etc.) until you reach the bottom.” o “Return to the top line and read aloud the second letter and the next-to-last letter of each line (F-H, B-R, etc.). “ o “Return to the top line and read aloud the third letter and the third-from-the-last letter of each line (N-C, A-K, etc.).” o “Return to the top line and read aloud paired opposite letters on a diagonal from upper left to lower right (O-L, B-P, etc.), then from lower left to upper right (H-E, M-R, etc.).” Guidelines: o For variety, try reading the chart in different directions. Instead of going from left to right, go from right to left. Then try top to bottom and bottom to top. The most difficult is to read the chart on a diagonal. o As you read aloud each letter, try to maintain a steady rhythm. o If you have more difficulty when using one eye compared with the other, spend more time using the difficult eye. o If you have trouble keeping your place, move closer to the chart. This should make it easier. Then move back again. o If you still have difficulty, use a chart with wider spacing, or cut the chart into four equal sections and space them out on the wall. o A possible therapy time: 3-4 cycles OD/OS/OU Comments: o May be performed monocularly or binocularly o Various combinations ▪ Whole chart ▪ 2 charts ▪ Quadrants ▪ Single strips • Straight • Offset o Inter-sensory integration ▪ Metronome o Loading ▪ Balance board ▪ Bean bag ▪ Number/letter counting ▪ Near-far hart chart (component of near-far accommodative rock). 65 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Hart Chart Coding • • • • • Purpose: saccadic and fixation therapy with an element of visual figure-ground and visual memory skills required Equipment: o Large Hart Chart o Hart Chart coding worksheet o Eye patch (optional) Set-up and instructions: o Tape the large chart to a wall. Be sure that there is good lighting on the chart. o Patient should sit5 feet or further from the chart. o Put a patch over one eye if the task is to be done monocularly. o Say, “You are going to decode a message. To find your first letter look at this set of numbers. It looks like subtraction, but it is actually a team of numbers that tells you where to look on the letter chart to find your letter.” o “The first number tells you how far to count down (or tells you your row.) The second number tells you how far across to go (or tells you your column.” o “Write down your letter and keep going.” Guidelines: o Always count down first, then across! o This activity also provides a small accommodative rock. o If you have more difficulty when using one eye compared with the other, spend more time using the difficult eye. o If a person has great difficulty performing this activity far-to-near, it can be taught with the Hart Chart at a table or a desk. Comments: o May be performed monocularly or binocularly o Print custom codes at www.HartChartDecoding.com (Thank you, Joanna Wen, OD!) o Inter-sensory integration ▪ Metronome o Loading ▪ Work for speed ▪ Distract patient with conversation ▪ Put the Hart Chart on a pegboard rotator 66 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Computer training techniques • • • • • • Applicable to fixation, pursuit, saccades, accommodation, and vergence o Good addition to basic skills techniques already discussed. o Very useful when issues of patient reliability and cooperation are present. o May be performed monocularly or binocularly. o Can be used with 3D goggles or red/blue glasses depending on the program or computer. ▪ The 3D goggles help reduce suppressions by alternately presenting the targets to the right and left eyes. ▪ Red/blue glasses do not affect suppressions and can be used later if desired. VTS3/VTS4 o Pursuits: Developed by Jeffrey Cooper, OD ▪ Performed monocularly or binocularly. ▪ Patient follows a moving “E” and notes its orientation via the joystick or keyboard. o Saccades ▪ Performed monocularly or binocularly. ▪ Patient reports the orientation of an arrow via the joystick or keyboard. Computer Perceptual Therapy (CPT) o Visual Tracing (CPT programs were developed by Sidney Groffman, OD) ▪ Patient visually traces a path from a starting letter to an ending number ▪ Can run with 2-4 lines on the screen, increasing difficulty ▪ Can use mouse (with/without audio feedback) or keyboard for entry o Visual motor integration (VMI) ▪ Similar to the “breakout” game. ▪ Variables include speed of ball, size of paddle and visual distractors. ▪ Performed monocularly or binocularly. ▪ Simultaneously works on basic pursuits and eye-hand coordination. Computer Assisted Vision Therapy (CAVT, aka the Vogel programs) o Track and Read o Visual Thinking 101 o Visual Information Processing Skills (VIPS) Super DxBall o Commercially available (internet shareware). o Only parameter changes are 4 levels of difficulty. Vision Builder o Saccades o Tennis 67 All material contained in this manual is copyrighted. Please do not reproduce or distribute. • Optics Trainer o Uses a combination of a touch screen and an eye tracking bar o Not all programs can be used with the eye tracker o Has modules for saccades, pursuits, steady fixation, visual discrimination, visual figureground, and visual spatial skills o Some modules can be used with red-green glasses for anti-suppression therapy o Activities Include: ▪ Balloon Count: Using the eye tracker, patient fixates on balloons in numerical order until they pop. Can also be used for eye-hand coordination by pressing balloons in order with the touchscreen. ▪ Peripheral Awareness: Using peripheral vision, determine which letter matches with the center, fixated letter. Tap the matching letter. Eye Tracking monitors patient fixation to the center target. Peripheral targets are hidden if the patient looks toward the periphery. ▪ Asteroid Defense: Using the eye tracker, protect your ship from the oncoming asteroid onslaught. Quickly fixate asteroids to explode them. ▪ Eye Maze: Using the eye tracker, fixate numbers in order to complete the maze. ▪ Saccade Pop: Using the eye tracker, quickly look at the circle that lights up, fixating it until it pops. Can be set for horizontal, vertical, or random mode. ▪ Ball Maze: Using the eye tracker, guide the ball through the maze. Collect coins as the ball rolls into them. ▪ Reading Trainer: A guided reading program that uses the eye tracker. A rate of reading speed is set. An alarm sounds if your patient reads too fast or too slowly. Activity includes comprehension questions. ▪ Visual Discrimination: There are four modes: PDBQ, 2-numbers, 3-numbers and 2-letters. Selects the targets that match the target displayed on the balloon the bear is holding. When you thinks you have found all the targets, press the button on the bottom of the screen. If there are unfound targets, the screen will indicate how many are left. ▪ Sequences: A simpler version of Michigan tracking. From a field of distractors, find the targets in the same sequence as the pattern shown. ▪ Flip Forms: An image is presented, and the patient must create a pattern in the correct orientation based on instructions (flipped sideways, upside down, or rotated right or left.) ▪ Reversals: Using the touchscreen or computer mouse, the patient touches/clicks all backwards letters and numbers on the screen as quickly as possible. ▪ Hidden Objects: Patients locate specific pictures from a field of pictures. Target can be shown as a picture or the word for that picture. Pictures get smaller as difficulty level increases. 68 All material contained in this manual is copyrighted. Please do not reproduce or distribute. • Recording for computer training techniques o Document the following • Monocular, bi-ocular or binocular • Whether one eye was easier • Accuracy • Body posture (if unusual) • Motor overflow (if present) • Automaticity • Whether the technique was set for antisuppression • Was eye tracker, mouse, keyboard, or touchscreen used for response Endpoints for eye movement therapy: The endpoint for version eye movement skills is somewhat more nebulous than some of the other areas of therapy such as accommodation or vergence. A good rule of thumb would be to discontinue therapy when the criteria that we are probing (accuracy, overflow, automaticity, etc.) are appropriate for the age level. To verify this we should re-evaluate the initial findings and investigate current symptoms. Notes: Generally, most clinicians work the monocular skills first and the binocular last. In certain cases such as low level patients or trauma, the choice may be made to only treat in a binocular modality. When doing close work with pencil and paper, it is suggested that the patient be at positioned at his Harmon distance. When performing techniques with a pointing stick, the patient should be set up so that he can touch the chalkboard or Marsden ball. With flashlights, a distance of about 8-10 feet is most appropriate. Try to have a time limit for each technique. Recommended goals may be 5 minutes per eye or going through a chalkboard pattern 5 times per eye. Homework should take about the same time. 69 All material contained in this manual is copyrighted. Please do not reproduce or distribute. THERAPY TECHNIQUES FOR READING-RELATED EYE MOVEMENTS: Michigan tracking (aka Ann Arbor tracking) • Purpose o To improve the accuracy and speed of fixation and small-angle saccades. o To improve visual discrimination, left-to-right directionality, and eye movement skills used to read across a line. • Equipment o letter tracking sheets o pencil o eye patch (optional) • Recommended Office Vision Training Instructions o “Begin to draw a line under the letters on the first row. Loop a circle around the first "a" that you come to on the line.” o “Continue until you come to the first "b" and loop it, then "c", and so on, until you have circled each letter of the alphabet in order.” o “Go to a different paragraph or section of letters and this time just circle all the letter a’s. Now take the next paragraph or section and circle all of the letter b’s. The next one c’s and so on.” o “Now do a word search. Take a word that the child knows how to spell, and circle each letter in order (for "cat" it would be the first "c," then the first "a" after that, then the first "t" after that).” • Possible therapy duration o 10 minutes, two times each day. • Comments: o Monocular or binocular o Underline letters for patients with reduced abilities o Speed/accuracy trade-off o Can be performed at home if the materials are available. o Other home techniques (ones with asterisks jointly train saccades and pursuits) include: ▪ Line design books* ▪ Pencil and paper Groffman tracing* ▪ Pencil and paper Geo shapes* COMPUTER TECHNIQUES VTS 4 or 4 Basic saccades • Purpose: to improve the accuracy and speed of fixation and small-/moderate-angle saccades. • Performed monocularly or binocularly. • Patient will see an arrow placed on the screen and key into the joystick the orientation: up, down, left, right. CPT Visual Scan (for basic saccades as well as figure/ground) • Purpose: to improve the accuracy and speed of fixation and small-angle saccades. • Monocular or binocular. • Patient finds targets hidden in a field of distractors. • Targets and distracters can be numbers, lower or upper case letters or symbols. 70 All material contained in this manual is copyrighted. Please do not reproduce or distribute. CPT Visual Search • • • • • Purpose: to improve the accuracy and speed of fixation and small-angle saccades. Patient has to find a specific sequence of numbers, symbols or letters. Variables o Number of elements in the sequence o Number of columns and rows. The computer displays the number of targets, omissions and errors. Monocular or binocular. CPT Visual Coding • Purpose: to improve the accuracy, speed, and automaticity of fixation and small-angle saccades. • Not a substitute for phonetic therapy when reading is a problem. • Analogous to the skills required for Tachistoscope. • More memory dependent than Tachistoscope (when done correctly). • A therapy sequence could be numbers>>letters>>symbols CPT Visual Perceptual Speed • Purpose: to improve the accuracy, speed, and automaticity of fixation and small-angle saccades. • The same as computer search except after each answer the target sequence changes. • Develops ability to separate important from unimportant visual information, i.e.: figure-ground. • Can decrease verbalization as a support mechanism by using symbols. Vision Builder Moving Window • aka Guided Reader Moving Window • Binocular PAVE Computer Program • Moving window (Guided Reader) • Assorted eye movement skills Recording for all techniques • Document the following o Monocular, bi-ocular or binocular o Which eye was easier o Accuracy o Body posture (if unusual) o Motor overflow (if present) o Automaticity 71 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Endpoints: As with version eye movements, the endpoint for reading eye movement skills is more nebulous than some of the other areas of therapy such as accommodation or vergence. A good rule of thumb would be to discontinue therapy when the criteria that we are probing (accuracy, overflow, automaticity, etc.) are all appropriate for the age level. To verify this we should re-evaluate the initial findings and investigate current symptoms. Notes: Generally most clinicians work the monocular skills first and the binocular last. In certain cases such as low level patients or trauma, the choice may be made to only treat binocular abilities. When doing close work with pencil and paper, it is suggested that the patient be at his Harmon distance. When performing techniques with a pointing stick, the patient should be set up so that they can touch the chalkboard, computer, or paper. With flashlights, a distance of about 8-10 feet is most appropriate. Try to have a time limit for each technique. Recommended goals may be 5 minutes per eye or going through a chalkboard pattern 5 times per eye. Homework should take about the same time. 72 All material contained in this manual is copyrighted. Please do not reproduce or distribute. THERAPY TECHNIQUES FOR ACCOMMODATION MONOCULAR ACCOMMODATIVE THERAPY WITHOUT LENSES Near-Far Hart Chart Rock (NFHCR) • Purpose: o To develop flexibility in the change of focus when looking near to looking far. • Equipment: o One large Hart alphabet chart o Eye patch o One small Hart chart o Tape • Set-up and instructions: o Tape the large chart to a wall. Be sure that there is good lighting on the chart and that you have a clear path to move backward. o Have the patient stand 8-10 feet from the chart. If they have mildly reduced VA, then they may stand somewhat closer. (Hart chart is 20/20 at 20 feet.) o Place a patch over one eye. o Hold the small letter chart at your normal reading distance (16 inches from the eyes for adults and 12 inches for children). o “Read the first line on the large chart all the way across (O, F, N, P…). Now look down and read the second line on the small chart (Y, B, A, K …). Repeat the cycle with the next row”. o “When you get to the bottom of the chart, take one step back and see if you can still see the wall chart clearly”. If so, repeat previous step. If not, record how far the patient is from the distance chart. o Switch the patch to the right eye and repeat steps 4 through 6. • Guidelines: o If your patient cannot get as far from the wall chart with one eye as the other eye or if it takes more time to clear either chart with one eye compared with the other, spend more time with the eye that is sluggish. o If your patient has no trouble keeping his place, try switching from near to far and back again once every five letters until he gets to the end of each line. o For variety, try reading the chart in different directions. Instead of going from left to right, go from right to left, then try top to bottom and bottom to top. Reading the chart diagonally is the most difficult. o There are number and picture versions available if the standard one proves too difficult. • Possible therapy duration: o 5 minutes each eye daily. o 1-2 cycles each eye. • Comments: o Near card held in the hand at 16 inches, far card on the wall at 8-10 feet. o Earliest standard technique. o Increasing difficulty: ▪ 1 line at a time ▪ 5 letters far - 5 letters near ▪ 3 letters far - 3 letters near o Discontinue this technique when the patient can easily shift from near to far and there is no loss of place o Good home technique. 73 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Jensen Rock • • • • • Purpose: o To further develop the amplitude of accommodation. o Usually best used after an initial re-evaluation and the patient’s amplitude is still reduced. o Similar to NFCHR but with one important addition. Equipment: o As NFHCR Set-up and instructions: o As NFHCR with the following change: ▪ The near Hart card is read at 16 inches and then slowly moved closer until it begins to blur. It is then moved out until it clears and kept clear for about 3 seconds. The patient then looks out toward the far card and reads the next line. o “Read the first line on the large chart all the way across (O, F, N, P . . .), then look down and read the second line on the small chart (Y, B, A, K . . .). Next, slowly bring the near chart closer until it begins to blur. Now slowly back the card away until the letters are clear and hold it for 3 seconds. Repeat the cycle with the next row.” Comments: o Avoid this technique when a patient has poor plus lens (release) facility. o Discontinue the technique when the patient can keep the card clear for about 3 seconds at 3-4 inches and the ability is similar between the 2 eyes. Then recheck your amplitudes. o The process works very fast but be sure your patient is not inducing distance blur. o Good home technique. Recording: o Note the distance from the patient to the far chart. o Note the closest distance the patient could bring the small hart chart. o Note any difference between the eyes. 74 All material contained in this manual is copyrighted. Please do not reproduce or distribute. MONOCULAR ACCOMMODATIVE THERAPY WITH LENSES Loose lens tromboning • Purpose: o To train accommodation in patients with exceptionally poor facility. o Very useful with poor minus facility. • Equipment: o Appropriate minus lenses. o Eye patch. o Hart chart for distance. o Small Hart chart or appropriately sized text (20/30-20/60) for near. o Marsden ball (optional). • Set up and instructions: o For distance therapy, the patient should be standing approximately 8-10 feet from a Hart chart or Marsden ball. He should be wearing his habitual Rx and the patch. He is told “I want you to hold the lens at arm’s length while you look at the letter chart. Read the letters as you slowly pull the lens toward your eye. Tell me if and when the letters become blurry.” o For near therapy, the patient should be seated, patched and wearing his distance Rx. He is told “I want you to hold the lens over the near Hart chart letters and slowly pull the lens toward your eye while keeping the letters clear. Tell me if and when the letters become blurry.” o Repeat with the other eye. Comments: o o • Always monocular Generally a near point technique but can be used for distance if necessary ▪ Start with a –4.00 to –6.00 lens if used as a distance technique ▪ Start with as little as a –2.00 lens if used as a near technique o When possible, work on patient’s awareness of how it feels as they clear the lens. o The Marsden ball may be set in motion for a more challenging task. o Work on the ability to change accommodative status by tightening and relaxing the body and then by pure visual imagery and visualization. o Consider this a technique used primarily to “jump start” the accommodative system. o Discontinue the technique when the patient can accomplish standard MAR techniques. o Appropriate home technique Recording o Whether task was done at near or far. o Closest distance patient could bring the lens for each eye. o Power(s) of lens used. o Size of target used. 75 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Lens sorting • • Purpose: o To develop awareness of small changes in accommodation. Equipment: o Small Hart Chart (or any reading material of similar size) o Large Hart chart, Marsden ball or other target for distance o Eye patch o Unmarked loose lenses between -0.50 and -6.00 Set up and instructions: o Have an array of minus lenses (about 10) of various powers spread on a table. The patient will be asked to look through each lens at a target about 10 feet away and assess the relative minification changes. He will then be asked to place the lenses in a row with powers decreasing going from left to right. The distance target can be a person's face, a picture, a large Hart chart, the Marsden ball or any object. o Place a patch over one eye and have the patient hold the first lens in front of his other eye at a distance of 15 cm (approximately 6 inches). o Tell the patient: “I want you to look at the large Hart chart through each lens. Based on how small the chart looks, I want you to places the lenses from left to right with the lens that makes things look smallest on the left”. Remind him that the object will appear smaller. o Scramble the lenses and repeat with the other eye. o Repeat the entire process at near, this time using the small Hart Chart or equivalent size print and again arrange the lenses left to right. At near this would be based on the order of most difficult to clear to easiest to clear. • Comments: o At the outset the therapist should give the patient -1.00 diopter increments between lenses. As the patient becomes more proficient and his JND (just noticeable difference) improves, narrow the level to -0.25 diopter steps. o When the patient is observing the distant object of regard through the minus lens, the therapist should check to confirm awareness of localization and SILO. o Possible therapy duration: 5 minutes each eye, twice daily. o Technique is only performed monocularly. • Recording: o Accuracy of the lens orientation o Fatigue o Whether performed at distance or near o Range of lenses used 76 All material contained in this manual is copyrighted. Please do not reproduce or distribute. Split Pupil • Purpose o Develops the ability to quickly and efficiently stimulate and relax the focusing system. o Unlike tromboning, this is an accommodative jump procedure. • Equipment: o Minus lenses o Marsden ball or distance Hart chart o Metronome o Patch • Set up and instructions: o For distance therapy, the patient is patched, wears his distance Rx and stands approximately 8-10 feet from a Hart chart or Marsden ball. The lens is held from below with the edge at mid-pupil. This will result in monocular diplopia with the higher target seen above the lens and the lower target seen through the lens. The patient is told “I want you to hold the lens in front of your eye and alternately clear the letters on the 2 charts (or Marsden ball), first above and then through the lens”. o Repeat with the other eye. • Comments: o Monocular technique o Use a -4.00 to –6.00 lens o Generally performed at distance (8-10 feet). o Can use a Hart chart or Marsden ball o Hold the lens with the edge just at the pupil. The prismatic effect will create a double image; one in the lens and one outside. • Recording o Power(s) of lens used. o Type of target. o Which (if any) eye was harder. o Was it easier to clear outside the lens or inside? Monocular Accommodative Rock (MAR) • Purpose: o To improve accommodative facility, monocularly. o Helps the patient to develop speed, magnitude and accuracy of the accommodative response. • Equipment: o Michigan (MT) track, PS (number) forms or any reading material not larger than 20/50 unless the patient is amblyopic and then the target should be 2 lines over best VA. o Loose lenses ranging from +0.25 to +3.00 and -0.25 to -6.00. o Eye patch • Procedure: o Patient should be seated with good posture at either the Harmon distance (elbow to 2nd knuckle) or 16 inches. o One eye is patched and the patient is given the appropriate lenses in a holder or taped together. o Depending on the target used, the patient will flip back and forth between the lenses. o An instruction set for MT could be: “I want you to look through this lens and find and circle the first letter ‘a’ that you see and then the next ‘b’. Now switch to the other lens and find the next ‘c’ followed b