Optometry II Midterm 1 2024 PDF

2024 OPTOMETRY II OPTO 5272 January 3, 2024 Lecture 1 - Course Intro & Spherocylindrical Retinoscopy Lucy Kehinde Darnell, OD, PhD, FAAO Refractive Error Review 1 ...

2024 OPTOMETRY II OPTO 5272 January 3, 2024 Lecture 1 - Course Intro & Spherocylindrical Retinoscopy Lucy Kehinde Darnell, OD, PhD, FAAO Refractive Error Review 1  2024 Spherical refractive error possibilities f) (t) Spherocylindrical classifications Simple astigmatism retina one behind Simple hyperopic astigmatism – one emmetropic principal meridian, one hyperopic Simple myopic astigmatism – one emmetropic principal meridian, one myopic one in front retina Compound astigmatism behind both retina Compound hyperopic astigmatism – both principal meridians hyperopic Compound myopic astigmatism – both principal meridians myopic retina both in front of ________ astigmatism Mixed One hyperopic principal meridian, one myopic principal meridian 2  2024 Spherocylindrical refractive error possibilities Astigmatism "not football" phrasing - a could be construed as kentosones flat Steep W __TR: __TR: A vertical The ___________ meridian of the The ___________ horizontal meridian of the eye is steeper (has more optical eye is steeper (has more optical power) than the ________meridian. horizontal vertical meridian. power) than the ________ 3  2024 Retinoscopy of an eye with regular astigmatism will have two different powers in the principal meridians; One stronger meridian 90° from the weaker meridian. In _________ irregular astigmatism, the principal meridians are not 90° apart (this is rare). In _________ oblique astigmatism, the principal meridians are not oriented horizontally or vertically. Astigmatism Classifications With-the-rule: meridian of greatest refractive power is within ___⁰ of 30 vertical defining vertical as 900 Correcting cyl lies between 0 and 030 (or between 150 and 180) Against-the-rule: meridian of greatest refractive power is within 30⁰ of horizontal defining horizontal as 1800 Correcting cyl lies between ____ 660 and ____ 1200 Oblique: meridian of greatest refractive power is oblique with respect to the vertical or horizontal meridians Correcting cyl lies between 030 and 060 (or between ___ 120 and ___) 150 In other words, correcting cyl is +/- ___ 150 from 45 and 135 4  2024 * not on exam ignore Astigmatism Classifications Ex: OD: -1.75 -1.50 x 167 OS: -1.50 -2.00 x 011 Symmetrical astigmatism: weakest meridians (or strongest meridians) of both eyes sum up to 180⁰ Homologous symmetrical astigmatism: if WTR Example: x 175 in OD, x 005 in OS --> 175 + 005 = 180 Heterologous symmetrical astigmatism: if ATR Example: x 080 in OD, x 100 in OS --> 080 + 100 = 180 Asymmetrical astigmatism: weakest (or strongest) principal meridians of both eyes do not sum up to 180⁰ Homonymous: both eyes are WTR (or both are ATR); meridian pairs are within 30 degrees of parallel to one another (see example above) Heteronymous: one eye WTR, one eye ATR Astigmatism Classifications Total manifest astigmatism – measured in subjective refraction (JCC) Jackson Cross Corneal astigmatism – results from meridional variation in refractive cy) power of anterior surface of the cornea Measured with keratometer Internal/_______ residual /physiological astigmatism – in posterior cornea or crystalline lens (about 0.50 DC) Measured with Lenstar or Pentacam Vertical axis Ret - lens + cornea refractive power 5  2024 Sphero-cylindrical Retinoscopy Steps 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ with motion. Pushing it down - with " "down with G A C (outer wheel) B (inner knob) 6  2024 Spherocylindrical Retinoscopy Steps 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ with motion. **Neutralize the MOST PLUS (least minus) meridian FIRST Weaker (most PLUS = least minus) meridian Stronger (least PLUS = most MINUS) meridian 7  2024 Spherocylindrical Retinoscopy Steps 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ motion. **Neutralize the MOST PLUS (least minus) meridian FIRST You should only have _________ against motion remaining 90° away from the MOST PLUS meridian Spherocylindrical Retinoscopy Steps 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ motion. **Neutralize the MOST PLUS (least minus) meridian FIRST You should only have _________ motion remaining 90° away from the MOST PLUS meridian 3. Set the cyl axis of the phoropter and the _________________ beam to scope the MOST MINUS (least plus) meridian. 8  2024 Use the outer CYL AXIS wheel to align the minus cylinder lens with most minus meridian. Rotate your retinoscope beam to be parallel with the CYL AXIS Spherocylindrical Retinoscopy Steps 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ motion. **Neutralize the MOST PLUS (least minus) meridian FIRST You should only have _________ motion remaining 90° away from the MOST PLUS meridian 3. Set the cyl axis of the phoropter and the _________________ to scope the MOST MINUS (least plus) meridian. minus 4. Add _______ cylinder power until you have neutralized the against motion. 9  2024 Use the inner CYL POWER knob to neutralize the remaining against motion Spherocylindrical Retinoscopy Steps 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ motion. **Neutralize the MOST PLUS (least minus) meridian FIRST You should only have _________ motion remaining 90° away from the MOST PLUS meridian 3. Set the cyl axis of the phoropter and the _________________ to scope the MOST MINUS (least plus) meridian. 4. Add minus cylinder power until you have neutralized the against motion. Take distance 5. _____________________________________! out your working 10  2024 -6.00 165 -1.50 075 - 4 50. x165 -6.00 165 -1.50 075 -1.50 -4.50 X 165 11  1/7/2024 OPTOMETRY II Lecture 2 – Retinoscopy on a Patient & Direct Ophthalmoscopy January 8, 2024 Spherocylindrical Retinoscopy Review 1. Align Purkinje images! 2. Scope all meridians and determine the two major (principal) meridians. Get rid of all _____ with motion. **Neutralize the MOST PLUS (least minus) meridian FIRST You should only have _________ against motion remaining 90° away from the MOST PLUS meridian 3. Set the cyl axis of the phoropter and the _________________ retinoscope to scope the MOST MINUS (least plus) meridian. 4. Add minus cylinder power until you have neutralized the against motion. 5. Remove your working lens power! 1  1/7/2024 Retinoscopy on a Patient Patient Set-up  Room lights should be OFF (or very dim) E see both fusing eyes - not  Patient must be bi-ocular and able to view the distant target with - the eye not being scoped  Block eye being scoped with your head completely block  Patient's accommodation must be relaxed. This is accomplished by: Using cycloplegic eye drops - tripacamide OR cyclopentolate adding (t) lens "Fogging" the patient (fog the eye NOT being scoped) Dial in 1.50 or 2.00 of additional plus beyond the patient's refractive error Obtain obvious _______ against motion in all meridians * adding too much (+) > - induce myopia 2  1/7/2024 You Patient Scoping the right eye Patient Scoping the left eye You Patient 200 > - diopter of cyl 𝜀 = 𝑜𝑏𝑙𝑖𝑞𝑢𝑖𝑡𝑦 𝑜𝑓 𝑜𝑏𝑠𝑒𝑟𝑣𝑎𝑡𝑖𝑜𝑛 𝜀 vertical As 𝜀 increases, the amount of cyl power measured in the ____________ axis increases. 3  1/7/2024 Retinoscopy on a Patient - Steps 1. Give the patient instructions (p. 15 of lab manual) 2. Fog the patient’s left eye (add enough plus to eliminate all WITH motion) 3. Position yourself at your working distance in front of the patient’s right eye, being careful not to block the left eye 4. Neutralize OD 5. Neutralize OS both 6. ________________________________! Take out working lens eyes 7. Record your net findings After retinoscopy: Check visual acuity 4  1/7/2024 Checking VA after retinoscopy 1. Keep the room lighting dark/very dim 2. 20/50 to _____ Display the ______ 20/20 lines 3. Occlude OS and encourage patient to read the lowest line possible 4. Document the acuity - Continued in Lecture 3 – Subjective Refraction Part 1 - Intro to Refraction 5  1/7/2024 Manifest Refraction Sequence Overview over minus - > have to accommodate at distance Determine Sphere Power Starting Point Monocular at hear cause HA *JCC to Refine Cylinder Axis , *JCC to Refine Cylinder Power Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere *JCC = Jackson Cross Cylinder Manifest Refraction Goal: to create artificial emmetropia using corrective lenses Light from infinity focuses on the retina when accommodation is relaxed Use the maximum amount of plus (least minus) for best visual acuity (BVA) ______ 3 25 +0 DS over distance BVA causes ________. blur Patient cannot relax accommodation further ideal end point ______ 25 - 0. change DS over distance BVA results in __________________ no Patient accommodates to move retinal image on to the retina 6  1/7/2024 Direct Ophthalmoscopy vs Advantages of D.O. Disadvantages of D.O. Easier to learn (relatively) Limited field of view High magnification (__ 15 X) Monocular procedure no depth perception Allows for evluation of Dim image (swollen edeia) or structures in front of the Close working distance retina No image reversal 7  1/7/2024 Direct Ophthalmoscopy Set-up 1. Reduce ambient light Thumb here 2. Grasp like a microphone with index finger extended to reach the wheel and thumb on the thumb-rest  If examining ___ OP hold in right hand and hold the DO to your right eye  If examining ___ OS hold in left hand and hold the DO to your left eye (or else...) 3. Give patient an appropriate fixation point "Is that okay wf you... " up in corner and away 4. Set power wheel to ~ ______BS + 10 00. towards you Direct Ophthalmoscopy Procedure 1. Shine light into patient's pupil __________ 25cm away from the patient, slightly temporal from line of sight 2. Examine optical media (look for opacities) 1. If the opacity moves with the beam (same direction) it is in front of the posterior lens capsule 2. If the opacity moves in the opposite direction, it is behind the posterior lens 8  1/7/2024 Direct Ophthalmoscopy Procedure 3. Reduce the plus power as you approach the patient (steady yourself) 4. Continue to approach until your finger contacts their cheek 5. Examine the optic disc Color Margins Cup-to-disc ratio around ~ 0 7. pallor swollen large Cup-to-disc blurred rativ margins hemmorrhage "When in doubt, 0 3". 9  1/7/2024 Direct Ophthalmoscopy Procedure 6. Examine vasculature macula maculopathy 7. Examine the macula hemorrhage nothing normal torchoors Course exudate leakage (windy, not Smooth) ~ white-nerve fiber layers ! * discoloration the macula in 10  1/7/2024 Auxiliary features Half light Polarized Slit Cobalt blue Red free Grid ("hemispot") filter Pass light Reduce Corneal Retinal Approximate ________ Contour thru clear corneal defects bleeds distances portions reflections Bend in beam- not flat dodge Blood / opacity hemorrhage "Something in way" Cobalt blue filter Need to instill vital dye (sodium fluorescein) to illuminate defects 11  1/7/2024 Getting started with EyeSi Simulator Email from VRmNet Web Portal [email protected] Complete online orientation before Lab 2 Set a new password (keep it simple!) 12  OPTOMETRY II Lecture 3 - Subjective Refraction Part 1 Monocular Subjective January 10, 2024 Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis Part 1 JCC to Refine Cylinder Power Monocular Subjective Sphere Part 2 Binocular Balance Binocular Binocular Subjective Sphere 1  Manifest Refraction Goal: to create artificial emmetropia using corrective lenses Light from infinity focuses on the retina when accommodation is relaxed Use the maximum amount of plus (least minus) for best visual acuity (BVA) +0.25 DS over distance BVA causes blur Patient cannot relax accommodation further, resulting in blur -0.25 DS over distance BVA results in no change Patient accommodates to move retinal image on to the retina - Retinoscopy - Habitual/previous Ry Autorefraction - Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis JCC to Refine Cylinder Power Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere 2 Sphere Power Starting Point Goals: Control accommodation (ensure it is relaxed) Refine sphere power to adjust location of Interval of Sturm so that Circle of Least Confusion is on the retina. dioptic midpoint - on the retina JCC to collapse interval …Refine sphere power to adjust location of Interval of Sturm so that Circle of Least Confusion is on the retina. 3 Checking VA after retinoscopy 1. Keep the room lighting dark/very dim 20120 lines 20/50 to _____ 2. Display the ______ 3. Occlude one eye and encourage patient to read the lowest line possible Change the letters The next steps depend on the patient’s acuity… If monocular acuity after ret is 20/20 Add ____ 0 50 plus sphere in ______+ DS steps until the patient. inducing myopia loses letters (i.e., loses at least 3 letters on the 20/20 line), then remove the last _____ 50 DS. +0. (tog) ↳ Do not offer minus e untilAt - los 4 Clinical Note for Sphere Power Starting Point: You MUST have the patient re-read the lowest line possible - after each lens change. Even if the patient says it “looks worse”, have them re-read the lowest line they can. Often, they will say it “looks worse” but will still be able to read the same size letters as before. If monocular acuity after ret is 20/25 to 20/30 Add _____ plus sphere in ____0 50 DS steps until the patient can no +. longer read letters on the lowest line they can see, then remove the last ____DS. +50 0. If the patient can no longer read some of the letters after the first +0.50 DS step, remove the +0.50 DS and try -0.50 DS and see if VA improves. If VA improved with -0.50 DS, leave it…if not, remove it. - - If the patient’s vision improves when you add +0.50 DS, keep adding plus in +0.50 DS steps until the patient loses letters (at least 3 or more) on the smallest line that they were ever able to read, then remove the last +0.50 DS step. 5 If monocular acuity after ret is 20/40 or worse Perform Monocular bichrome procedure (red-green test) one eye Add +0.50 DS to your net retinoscopy finding Ask patient if which side has sharper, darker and/or blacker letters (red vs green) If red, add ____DS - 25 0. If green, add _____DS + 0 25. Or Endpoint: Both sides look equal to the first green & response. This is the stopping point for the monocular bichrome procedure and is the sphere power starting point for subjective refraction for this eye. Monocular bichrome procedure (Red Green Test) Uses chromatic aberration of the eye - The red and green side will look equal when the green focus is anterior to the retina the same amount that the red focus is posterior to the retina. green-shorter red-longer Wavelength waveleng th in back of retina front of refina 6 Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis JCC to Refine Cylinder Power Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere "struddle" define cy) axis Jackson Cross Cylinder JCC is a lens with plus cylinder in one meridian, minus cyl in the other White dots = axis of the plus cylinder Red dots = axis of the minus cylinder In the figure below, the eye had no astigmatism and the JCC induced astigmatism (Interval of Sturm) Circle of Least Confusion is the same size in both flip positions 7  V( showing" , "or "2 Jackson Cross Cylinder Straddle Position (____) axis cyl Parallel Position (____) - Dots “straddle” the axis -Dots “parallel” to the axis O- parallel no 8  20/30 JCC to Refine Cyl Axis JCC in the straddle position Show patient two choices (flip positions) Ask which choice makes the letters look better Note that both choices may be blurry Always begin choices with a flip of the JCC - If axis is off, patient will choose option with red dot in the direction of the preferred axis use the red" Resultant axis created by phoropter cyl and JCC minus cyl in the chosen flip position is in the direction of the patient’s true axis Endpoint: both choices look “about the same” "What Looks better " I or ?? axis change JCC to Refine Cyl Axis Two flip choices: “1 or 2” 9  JCC to Refine Cyl Axis “Chase the red dots” If _____ - 1 00 DC or less: move axis ___˚. 20 If _____ - 25 1 DC or greater: move axis ___˚. 10 Decrease axis change with subsequent choices to bracket down to the endpoint Endpoint: both choices look the same - "I 2 or about · , " the same Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis JCC to Refine Cylinder Power - Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere 10 JCC to Refine Cyl Power Two flip choices: “1 or 2” JCC to Refine Cyl Power 11 JCC to Refine Cyl Power JCC to Refine Cyl Power red If patient reports letters look better when ______dots are parallel to the axis, add -0.25 DC If patient reports letters look better when ______ white dots are parallel to the axis, remove -0.25 DC To maintain circle of least confusion: Add ____ + 0 25 D sphere for every two clicks of cyl added. Add ____ 0 25 D sphere for every two clicks of cyl removed -. 12 Exceptions to checking JCC cyl axis first first !! erI n parallel position 1. Retinoscopy cyl power is low (______ 0 25 D or _______) -. 0 50.. C -. D C.. Check cyl power first to see if patient wants the cyl, then check axis, then do a final recheck of cyl power 2. No cyl found during retinoscopy or patient “kicks out” all cyl from retinoscopy Fish for cylinder: in FIRST, _______________ put -0 25 cyl. Then, set JCC to parallel position and see if cyl is accepted in four major meridians (axis _____ 180 , _____ 45 , _____ 90 , and _____ 135 ) If cyl is accepted (patient says “about the same” or prefers ‘red’), - check axis, then re-check power If cyl is rejected, remove the cyl - Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis JCC to Refine Cylinder Power Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere 13 Monocular Subjective Sphere Add ___ 6 clicks of plus sphere to blur eye "fogging" Ensure patient is unable to read the 20/20 line If the patient can read 20/20, add more plus! Isolate a single line of 20/20 letters Use a new 20/20 line for each eye Reduce plus (increase minus) in ____25 steps until the patient - 0. can read only 1 or 2 letters on 20/20 line Add additional -0.50 DS and check VA (patient should be able to read 20/20) Monocular Subjective Sphere If patient does not have equal acuity in each eye (e.g., amblyopic), refine sphere power: Try +0.25 DS: letters should look ________ worse If +0.25 DS does not make the line worse, try more plus Try -0.25 DS: letters should look __________________ the smaller same or Do not offer more minus than this if the patient already saw 20/20 BE CAREFUL NOT TO OVER MINUS 14  Monocular Subjective Sphere Young patients (including optometry students) will continue to accept more minus sphere if it is offered Letters look smaller when you over minus Patient must constantly accommodate to see clearly at distance BE CAREFUL NOT TO OVER MINUS Patient must demonstrate improved VA to receive extra minus Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis JCC to Refine Cylinder Power Monocular Subjective Sphere Binocular Balance Binocular Next lecture Binocular Subjective Sphere 15  OPTOMETRY II Lecture 4 - Subjective Refraction Part 2 Binocular Balance & Binocular Subjective January 17, 2024 Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis* JCC to Refine Cylinder Power* Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere 1 Binocular Balance > - Bincur- eyese opennee one Binocular = both eyes open and fixated on a single target Balance = balancing out the___________ Stimulus __________________________ to accommodate Why balance? Patients may accommodate during the monocular subjective and the amount of accommodation may differ between the eyes Example: Patient is a +2.00 hyperope in each eye - While testing OD, the patient accommodates +0.50, so you come up with +1.50 as the Rx for OD - While testing OS, the patient accommodates +1.00, so you come up with +1.00 as the Rx for OS 2  Why balance? (Example continued) Now with both eyes open, the patient’s Rx is “unbalanced” by 0.50 DS Accommodation is linked between the two eyes and it is NOT POSSIBLE accommodate different amounts with both eyes open. Now, one eye will ALWAYS be 0.50 DS out of focus. +1.00 OS Accommodate +0.50DS OU. OD now in focus. OS is still 0.50D out of focus. +1.50 OD Ex: +2.00DS hyperope OU The Goal of the Binocular Balance Ensure that both eyes will have equally clear retinal images simultaneously If the stimulus to accommodation is not balanced, then the two eyes will NEVER have equally clear retinal images at the same time 3 Why Worry about an Unbalanced Rx? Reduced ____________ Stereo acuity Central suppression asthenopia _____________ eye strain - (maybethey aia A significant imbalance (1D or more) may be amblyogenic in a child X Binocular Balance Techniques Prism Dissociated Balance  This is what we will do in lab Vectographic Balance  Requires a special projector slide Other variations exist, but these are the two most common 4  Prism Dissociated Balance 20/40 1. Display the ______ 10/15 rows of letters through ______ ↳ 2. Add _____ DS in front of both eyes + 0 50. Moves the images in front of the retina Helps you avoid over-minusing the patient 3. Instruct the pt to close eyes and use the Risley prisms to introduce 4 ___ BD ___ OD and 4 ___BU ___ OU Prism Dissociated Balance F Z B D E O F L C T A P E O T F T Z V E C L BU O H P N T Z P F Z B D E O F L C T A P E O T F T Z V E C L O H P N T Z 4 BD OD – Right eye sees the image ____ en The horizontal alignment of the targets may differ depending upon 4 BU OS – Left eye sees the image ______ de the patient’s phoria 5 Prism Dissociated Balance Patient Instructions “Now I would like for you to open your eyes and look to the end of the room. You should see two groups of letters, one up and one down. They both should be a little blurred. Is that correct?” “I want you to look back and forth at the top chart and the bottom chart and tell me which one looks better to you. Or do they look about the same?” Prism Dissociated Balance Procedure We want to equalize the blur between the two images, without over-minusing the patient. The endpoint is when both images look equally blurry (the same). If the patient reports the two targets look the same initially, then STOP. Otherwise… Add +0.25 DS to whichever eye’s image appears to be clearer or “better”. Ex: Top image is clearer: add +0.25 DS to the right eye Ask the patient to compare again after making the change. matches the blur of the other 6  Prism Dissociated Balance Procedure * Ifadding the patient reports one target looks clearer than the other and +0.25 DS causes a reversal, stop at the choice that makes the two charts look most similar. It is unlikely to take more than one or two clicks of plus to equalize the two images if the patient easily read the same threshold line with each eye during the monocular subjective. shouldn't take more than 2 clicks If you find yourself adding more than a couple clicks of plus to one eye to equalize the two images, first back up and re-do the monocular subjective. If you still cannot balance with one or two clicks, it is possible your astigmatism correction is off in the worse seeing eye. You may want to go back and check JCC. Prism Dissociated Balance Final Steps Once you equalize the targets, NEVER change the sphere power of just one eye again. This will undo your balance. Remove the Risley prisms and proceed to the binocular subjective. 7 Vectographic Balance Procedure Can be used instead of the prism dissociated if you have the equipment. Only do ONE! May be more accurate for some patients Includes fusion locks so that the patient is not dissociated With prism dissociated balance, patients with larger phorias may not perform as well as the targets drift apart horizontally A dissociated condition is not the normal viewing environment Vectographic Balance Procedure 1. Display the vectographic balance target 2. Dial in +0.50 DS over each eye 3. Dial in the Polarizing filter on the auxiliary wheel over each eye. 8 Equipment Needed Vectographic Balance Procedure Set-Up DZVN DZVN HOSR HOSR Z O D K Z O D K Left eye sees Right eye sees Put in polarizing filter these letters these letters over EACH eye Fusion Lock Seen by both eyes 9 Vectographic Balance Procedure Patient Instructions “Now I would like for you to open your eyes and look to the end of the room. You should see two groups of letters, one to the right of the vertical bar and one to the left of the vertical bar. They both should be a little blurred. Is that correct?” “I want you to look back and forth at the left and right side of the chart and tell me which side looks better to you. Or, do they look about the same?” Vectographic Balance Procedure …the same as prism dissociated. The endpoint is when the two sides of the target look equally blurred (the same). Add +0.25DS to the side which appears clearer until you equalize the targets. If the patient reverses between two choices, ask which of the choices makes both sides look the most similar. 10  Vectographic Balance Final Steps Once you equalize the targets, NEVER change the sphere power of just one eye again. This will undo your balance. Remove the polarizing filters and proceed to the binocular subjective. # When NOT to do a balance Patient has reduced best corrected acuity in one eye due to things such as: ______________ amblyopia ______________ pathology - cataract surgery In this case, you will spend more time refining your monocular subjective of each eye and prescribe that. 11 Manifest Refraction Sequence Determine Sphere Power Starting Point Monocular JCC to Refine Cylinder Axis* JCC to Refine Cylinder Power* Monocular Subjective Sphere Binocular Balance Binocular Binocular Subjective Sphere Binocular Subjective This is the final sphere determination for the patient’s prescription Procedure is the same as the monocular subjective except… Both eyes are open at the same time ALWAYS change the sphere power of both eyes together so as not to undo your balance 12 Binocular Subjective Steps 2 + 4 = 6 al 1. 4 clicks of plus over the endpoint Dial in an additional ___ of the balance + 1 50 DS in each eye) (The patient should now be blurred by about ______. 2. Ensure the patient cannot read the 20/20 line – otherwise add more plus 3. Display a single 20/20 size line that the patient has not seen before Binocular Subjective Patient Instructions "I now have a new line of letters in place which you haven't seen before. It should be so blurred that you can't make out any of the letters. Is that correct?" “I'm going to be doing a test like we did earlier. Only now, you will be seeing with both eyes instead of one at a time. I want you to look at the line of letters and tell me just as soon as you can make out any letter. Again, don't wait until you can read them all, but let me know just as soon as you can get one or two." 13 Binocular Subjective Procedure 1. Decrease the plus over both eyes simultaneously, one- click at a time, pausing several seconds on each one. - 2. Remind the patient to tell you when they can guess at one or two letters. - 3. Stop when the patient says they can guess and then verify that they correctly identify 1 or 2 letters, but don’t read - the entire line. 4. Decrease the plus by 2 more clicks and ask the patient to read the entire line. Binocular Subjective Procedure – Confirming the Endpoint 1. 20/40 to Confirm the endpoint by projecting a new _____ 20/15 chart and asking the patient to read the lowest _____ line they can. 2. Add 1 click of plus and ask, “What happens when I do this?” The patient will likely report it gets worse. 3. Go back to your original endpoint and tell the patient to observe the letters. Then add 1 click of minus and ask, “What happens when I do this?” The patient will likely report it looks the same. 14 Binocular Subjective Endpoint The endpoint is the spherical lenses that when +0.25 DS is added to each eye, causes the best visual acuity line to get slightly blurred. Taking out or subtracting a +0.25 DS has little effect or possibly causes the letters to look slightly smaller and darker. (This is the most plus, least minus sphere power that yields best visual acuity.) Be Careful Not to Over-minus! Never give the patient the additional click of minus unless they read more letters with it, or they state that it makes a significant improvement. i.e. make them earn or prove it Only ever offer 1 additional click of minus. Finish your refraction by projecting 20/40 down to 20/15 and taking OD, OS, and OU acuities with the final refraction. 15 Avoiding Accommodation During Refraction Perform a cycloplegic refraction - cycloplegia paralyzes accommodation Tropicamide – “damp” refraction; some accommodation may remain active Cyclopentolate – “wet” refraction; accommodation is completely paralyzed after 30 minutes - no binocular Perform a Binocular Refraction balance Both eyes are viewing throughout the entire refraction This refraction procedure still includes a binocular balance step Binocular Refraction Both eyes are open throughout the entire refraction sequence – mimics the “real world” Parts of the field of view will always be fused Helpful for patients with: Cyclophoria 2 – 20% of pts have a 10° or more shift in axis under binocular vs monocular conditions Nystagmus* Fluctuations in accommodation get more plus with binocular because accommodation relaxes 16 Pton exam Techniques for Binocular Refraction Septum – Turville Infinity Balance Physically block a portion of the target to each eye by placing a septum midway between the patient and the target Fogging – Humphriss Technique Slightly blur the central vision of the eye not being tested – such as with +0.75DS fog Polarization – Vectographic Slide, Borish Card Perform refraction with a vectographic slide in which some letters are present to one eye and not the other, and vice versa 17  OPTOMETRY II Phorometry Part I - Distance Testing January 22, 2024 Phorometry = Binocular Vision Testing Tests of accommodation and vergence performed with the phoropter Performed after the manifest refraction These are all SUBJECTIVE tests Not for patients with strabismus Today, we will discuss testing on non-presbyopic patients only 1  Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) Phoria Measurement E Not a replacement for the cover test (nolikeLabor e CANNOT identify strabismus (both ene Subjective testing – it is the amount of deviation the patient perceives The magnitude of the phoria can vary with a change in refraction (ex: an uncorrected hyperope who is now corrected) May be important to measure phoria through the new refraction before prescribing for the patient Large phorias may cause asthenopia or intermittent diplopia 2  Where would the patient see the targets? 6 BD - 12 BI - Horizontal Phoria Target: An isolated letter 1-2 lines above pt’s BVA in the poorer-seeing eye Patient sees: E OD E OS 6BD is the dissociating prism - separate the - - eyes 12BI is the measuring prism ~ we will adjust - - “You should see two groups of letters: one up and to the right, and one down and to the left. I’m going to be covering the lower set of letters and moving it. As soon as I show it to you again, tell me where it is: still to the left, to the right, or just underneath the top letters. Our goal is to line the two sets of letters up like buttons on a shirt.” 3  Flash the target, do not let them view with both eyes for long periods of time Always ask the patient to report the location of the lower target immediately after the uncover Change the prism by 3 to 4 pd each time to be efficient Horizontal Phoria Endpoint Patient sees: E OD E OS Example: Measuring prism landed on 3BI Patient has 3XP Horizontal Phoria Review isolated letter (1-2 lines above It's BVA in poorer-seeing eye) Target: ____________________________________________________ an 1. Place __________ 6 base down over the right eye 2. Place __________ 12 base over the left eye in 3. The “measuring prism” is the prism over the _____ left eye 4. Tell the patient you will be lining up the targets like buttons _____________________________________ on a shirt 5. YouOn do / do not need to “flash” the target 4  Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) Target: An isolated letter 1-2 lines above pt’s BVA in the poorer-seeing eye Vertical Phoria Patient sees: E OD E OS 6BD is the measuring prism - 15BI (12BI + Horizontal Phoria) is the dissociating prism - “You should see two groups of letters: one up and to the right, and one down and to the left. I’m going to be moving the upper set down. Tell me when the two sets line up, side-by-side like headlights on a car.” 5  If you measure a vertical, ALWAYS double check the alignment of the phoropter and that the patient is not tilting their head. No need to flash the target. Pts will not try to fuse vertical - - deviations. Change the prism SLOWLY. Vertical Phoria Endpoint Patient sees: E E OS OD Example: Measuring prism = 1BD OD Patient has 1pd Right hyperphoria Vertical Phoria Review an isolated letter (1-2 pt's lines above BVA in the poorer-seeing Target: ____________________________________________________ eye" 1. The prism over the right ______ eye is the “measuring prism”. 2. Tell the patient you will be lining up the targets like ________________________________________________ headlights on a car 3. You do /G - do not need to “flash” the target 4. phoropter alignment If you find a vertical phoria, recheck ____________________ before you believe the finding phoropter is Crooked 6 Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) Vergence Amplitudes (Ranges) Vergence: movements of the eyes… ~ Convergence | positive, base-out …in opposite Divergence | negative, base-in directions …to maintain Supravergence | base-down binocular fixation Infravergence | base-up Different types of vergence (we will discuss 2 today) maintaine Fusional Vergence target single - eye movements that are made to keep the fovea of both eyes directed at the target to maintain single vision Accommodative Vergence Increasing accommodation causes convergence Decreasing accommodation causes divergence ↳(t) 7 Vergence Amplitudes (Ranges) Uses BI and BO prisms Three endpoints Blur occurs when the patient runs out of fusional vergence and changes their accommodation to maintain single vision instead - - Break occurs when patient runs out of both fusional and accommodative vergence and sees double Recovery occurs when prism is decreased enough that the patient can fuse and regain single vision BI is performed before BO BI is “relaxing”. Patient relaxes accommodation to gain additional divergence. BO is “stimulating”. Patient increases accommodation to gain additional convergence. “Concerned” Vergence Amplitudes (Ranges) - The entire sequence (of BI and BO ranges) is not always performed during phorometric testing We are only concerned about the fusional vergence ability (ranges) necessary to keep both eyes fixated on a target Exophoria: Positive Fusional Vergence (Convergence) = ____ Bo Ranges BO - converge Esophoria: Negative Fusional Vergence (Divergence) = ____ BI Ranges BI-diverge 8  Horizontal Vergence Ranges Target: Vertical column of 20/20 – 20/50 letters Patient sees: D F O A T “I want you to concentrate on keeping the letters as clear as you can and tell me when they first start to get a little blurry or when they first break into two.” first Introduce BI simultaneously over each eye at a slow pace of 1pd / second. Patient sees: DD 5 + S FF O O Example: Patient reports double first. A A T T Break equals = 10pd BI Horizontal Vergence Ranges continued “Now, tell me when the letters first go back into one.” Decrease BI prism slowly until patient reports “single”. Patient sees: D Example: Pt reports single. BI Recovery = 4pd BI F Document findings: “Distance BI: X / 10 / 4” O A u T no blur You do NOT expect to get a blur reported on DISTANCE BI ranges. (If you did your refraction correctly, the patient is not accommodating to see at distance, and thus there is no accommodation to relax.) If you get a blur at distance during BI ranges, you have OVER- MINUSED the patient during your refraction. 9  Horizontal Vergence Ranges continued Target: Vertical column of Now, repeat the testing for BO ranges 20/20 – 20/50 letters BO Blur = ___pd 14 You do often get a blur on BO at distance. Patient increases accommodation to maintain single vision after fusional vergence runs out. BO Break = ___pd 16 10 BO Recovery = ___pd Document findings: “Distance BO: 14/16/10” Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) ↳ Vertical Vergence Amplitudes (only if a vertical phoria was found) - n 10  Vertical Vergence Amplitudes (Ranges) Only done if the patient had a vertical phoria Do not ask for blur – the patient CANNOT vary - accommodation to gain more vertical vergence Much smaller values than horizontal vergence amplitudes BD prism tests Supravergence BU prism tests Infravergence Vertical Vergence Ranges primitin *Take out Target: Horizontal line of letters 1-2 lines above the patient’s best VA in the poorer-seeing eye Place vertical prism over one eye only. Patient sees: APEOT F “For this test, I want you to concentrate on looking at the line of letters and keeping it clear. Tell me just as soon as the letters first start to double.” Introduce prism very slowly. Patient sees: APEOT F APEOT F Right Supravergence break = 2BD 11  Vertical Vergence Ranges continued “Now tell me when the letters first go back into one.” Decrease the prism very slowly. Patient sees: APEOT F Right Supravergence recovery = 1pd BD Then, repeat this testing for Infravergence – introduce BU prism. Asymmetric Supra and Infra vergence findings may confirm a vertical phoria Example: Right Supravergence = 2pd BD/1pd BD Right Infravergence = 4pd BU/2pd BU Midpoint of break = 1pd BU OD…this is suggestive of a right hypophoria - - - Asymmetric Vergence Ranges Example Asymmetric Supra and Infra vergence findings may confirm a vertical phoria - Example: Right Supravergence = 3pd BD/1pd BD ↳ Midpoint = 1 BU Right Infravergence = 5pd BU/2pd BU - Midpoint of break = 1pd BU OD Infra (BU) Interpretation: The patient has a R HypoP Alternative method (using above example): Supra (BD) Take the difference: 5 – 3 = 2 Divide difference by two: 2 ÷ 2 = 1 Assign prism direction of greater range: BU  midpoint = 1 pd BU OD 12  Horizontal & Vertical Vergence Ranges Review 70/50 20/70 (12 abble the poorer-seeing eye) to - lines a vertical like of letters horizontal line of letters (1-2 Target: _______________________________________________________ a lines above pi's BVA in the poorer-speils) - 70/50 to 70120 Horizontal For horizontal ranges, set both prisms to ______ zero Tell the patient to let you know when the targets 1. ______, bluw 2. ___________, break into two and 3. _____________________________ come back together Vertical For vertical ranges, place prism over ____________ one eye only Tell the patient to let you know when the targets break into two 1. _________________ and when they Come back together 2. _____________________________ Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria For next time… AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 13 Near Testing Put in the near IPD in the phoropter Move vergence levers in Place the roto card at 40cm Direct the reading lamp at the target Check near visual acuity To be continued in Lecture 6: Phorometry Part 2 – Near testing 14  OPTOMETRY II Phorometry Part II - Near Testing January 24, 2023 1 Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 2 1  Near Testing Put in the near IPD in the phoropter Move vergence levers in Place the roto card at 40cm - - Direct the reading lamp at the target Check near visual acuity - - 3 Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 4 2  Horizontal Phoria at Near Performed the same as distance, except: IPD is set for near Target: ________________________________on block of small letters the near roto card I (chart #____) set at 40 cm, under direct illumination 1. Place ____ 6 _____ dissociating BB over the right eye (this is the _______________ prism) 2. Place _____ 12 BI over the left eye (this is the ______________ _____ measuring prism) 3. Tell the patient you will be lining up the targets like buttons a shirt ______________________________________ on flash 5. You __________ need to “flash” the target 5 Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing - Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 6 3  AC/A Testing - visual discomfort AC/A = Accommodative Convergence to Accommodation Ratio How much a person’s eyes converge for every 1D increase in accommodation (or how much the eyes diverge for every 1D decrease in accommodation) Testing is performed only at near E also Do NOT perform the testing on someone who cannot - - binocular balance accommodate (i.e. pseudophakic or completely presbyopic) - Cataract SX 7 AC/A Testing You have just measured the horizontal (H) phoria for a target at 40 cm. Thus, the patient should have been accommodating about 2.50 D for that test. We will now repeat the horizontal phoria after we change accommodation by 1D either relaxing accommodation (dial in +1.00 over each eye) sph only or stimulating accommodation (dial in -1.00 over each eye) NOT _____ Both _________ !! Compare the horizontal phoria measurement to the new measurement – the difference between the two is the AC/A ratio 8 4  AC/A Testing Examples Example 1: exo is minus (-) eso is plus (+) Patient has a near H phoria of 6XP’ Dial in +1.00 over their refraction in each eye Re-measure near H phoria: 10XP’ The AC/A ratio is (-6) – (-10) = 4 / 1 i.e. The eyes diverged 4pd when accommodation relaxed 1D Example 2: Patient has a near H phoria of 2XP’ Dial in -1.00 over their refraction in each eye Re-measure near H phoria = 4EP’ The AC/A ratio is (4) – (-2) = 6 / 1 i.e. The eyes converged 6pd when accommodation was increased 1D **These were calculated by putting the value obtained during greater accommodation first and subtracting the value obtained during less accommodation.** 9 AC/A Testing You only need to measure the phoria through either +1.00 or -1.00 over the refraction, not both! The “sign” for exo is minus (-) and eso is plus (+) A negative AC/A ratio is NOT possible. This would mean the eyes diverged when accommodation was stimulated (and converged when it is relaxed). If you calculate a negative AC/A, you probably did the testing wrong, or tested someone who could not accommodate. This testing technique ASSUMES that the patient accommodates the full diopter (or relaxes the full diopter), so there is some margin for error. 10 5  Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 11 Vertical Phoria at Near Performed the same as distance, except: IPD is set for near block of small letters Target: ________________________________on the near roto card 1 (chart #____) set at 40 cm, under direct illumination 6 ____ 1. Place ___ measuring BD over the right eye (this is the _______________ prism) 2. Place ___ 12 ____ dissociating prism) BI over the left eye (this is the ______________ 3. Tell the patient you will be lining up the targets like __________________________________________ headlights on a cam 5. You _________ do not need to “flash” the target 12 6  Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 13 Horizontal Vergences Ranges at Near Performed the same as distance, except: IPD is set for near Target: “_____________________________” keep this how single on the near roto card 10 (chart #_____) set at 40cm, under direct illumination Set both prisms to ________ zere Slowly increase BI prism. Tell the patient to let you know when the targets blur 1. _________, (which may or may not happen) 2. _____________________ break into two , and It is normal to have a “blur” back together 3. ______________________________ come response when measuring BI ranges at near. Repeat with BO prism. 14 7  Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 15 Vertical Vergence Ranges at Near Performed the same as distance, except: IPD is set for near these words letter by letter Target: “_____________________________” read on the near roto card 4 set at 40cm, under direct illumination (chart #___) Place vertical prism over ___________. eye only one Start with prism set to _____. zere Tell the patient to let you know when the targets 1. _____________________ break intotwo and when they come back together 2. ________________________ 16 8  Order of Testing DISTANCE TESTING Horizontal Phoria Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NEAR TESTING Horizontal Phoria AC/A Testing Vertical Phoria Horizontal Vergence Amplitudes (BI before BO) Vertical Vergence Amplitudes (only if a vertical phoria was found) NRA/PRA (NRA before PRA) 17 NRA/PRA NRA = negative relative accommodation Plus to blur PRA = positive relative accommodation Minus to blur Directly measures accommodation (and indirectly measures vergence) - NRA is always done first (it is “relaxing”) 18 9  NRA 5 Target: Single line of letters on chart #___ Instruct the pt: “Look at the letters and try to keep them as clear as you can. Let me know as soon as the words first become slightly blurry.” Introduce plus over each eye simultaneously in +0.25DS steps, pausing at each step to give the patient time to respond. Stop when the patient reports a blur and verify that it stays a little blurry. For non-presbyopes, expect they will see a blur when you get to +2.50 over the distance refraction. You expect this because they are accommodating 2.50D to the 40cm target If it takes more plus for them to see a blur, you have OVER-MINUSED your patient 19 PRA 5 Target: Single line of letters on chart #___ (same as NRA) Start with manifest refraction in place Instruct the pt: “Look at the words and try to keep them as clear as you can. Let me know as soon as the words first become slightly blurry.” Introduce minus over each eye simultaneously in -0.25DS steps, pausing at each step to give the patient time to respond. LIP-lens in place/lens in Stop when the patient reports a blur and verify that it stays a little blurry. phoropter For non-presbyopes, you may be able to introduce -3.00 (NET) or more before it becomes blurry This is a measure of how much accommodative ability they have They are accommodating 2.50D for the 40cm target, plus whatever you can introduce in minus power on top of their refraction 20 10  NRA / PRA What about the indirect measurement of vergence? Vergence demand is dictated by the location of the target (e.g. 40 cm will have a given vergence demand). With this test, we are changing the accommodative demand with lenses, but we are NOT changing the vergence demand (i.e., target location). As you put in plus, accommodation relaxes, the eyes diverge (according to the AC/A ratio). The patient will see double, unless they voluntarily re-converge their eyes. As you put in minus, accommodation increases, the eyes converge (according to the AC/A ratio). The patient will see double, unless they voluntarily re- diverge their eyes. 21 NRA / PRA Most patients will not see double while you perform this test. If they do see double, that may indicate difficulty with one of the directions of fusional vergence. Based on whether you were testing NRA or PRA, you can identify which direction of fusional vergence is problematic for the patient. 22 11  Indications You Have Over-Minused the Patient The patient reports a blur on BI vergence ranges at DISTANCE The NRA finding is greater than +2.50 D 23 12  OPTOMETRY II Near Targets & Refractive Error Classifications January 29, 2024 Near Targets: Chart #1 Reading chart (20/60 to 20/20) Not an accurate measure of visual acuity Reading speed slows as threshold size is approached 1 Near Targets: Chart #2 Reduced Snellen (20/50 to 20/20) Use: Measure near acuity Near Targets: Chart #3 Cross cylinder grid Use: Fused cross cylinder (FCC) test for near add determination aka binocular cross cylinder (BCC) Not useful/reliable on non-presbyopes measures accuracy of accommodation - Will cover in Lecture 9 - Presbyopia 2 Near Targets: Chart #4 Horizontal line of words Vertical vergence amplitudes (ranges) Use: ____________________________________ ask break - recovery Near Targets: Chart #5 Single row of 20/20 letters NRA/PRA Use: _____________ Will cover more in Lecture 9 - Presbyopia 3 Near Targets: Chart #6 Sunburst dial Use: Determination of cylinder axis irregular astigmatism mild Keratoconus Interval of Sturm 4  WTR ATR _________ _________ & darker lines ↑ darker lines sees lines rest) y O M All Clock Dial *not included on the roto chart 300 increments 5 Clock Dial Example You: Tell me the numbers by the lines that appear darker, thinner or clearer. Patient: 2 and 8 seem darkest. 2 is the lesser number 2 x 30 = 60 Therefore, cylinder is x 060 Near Targets: Chart #7 Reading chart (20/200 to 20/80) 6 Near Targets: Chart #8 Reduced Snellen (20/200 to 20/60) Use: Visual acuity Near Targets: Chart #9 Reduced Snellen (20/200 to 20/20) Use: Visual acuity 7 Near Targets: Chart #10 Vertical column of words Use: ______________________________ Horizontal vergence amplitudes (ranges) Near Targets: Chart #11 7-line block of 20/20 letters Uses: Horizontal phoria __________________________ AC/A Ratio __________________________ Vertical Phoria __________________________ 8 Near Targets: Chart #12 Trifocal chart Use: Refractive Error Classifications 9 Refractive Status Classifications Emmetropia – incident parallel rays of light are imaged on the retina with accommodation at rest Ametropia – incident parallel rays of light are imaged either in front or behind the retina with accommodation at rest Hypermetropia (Hyperopia) The image is formed behind the retina with accommodation at rest Simple hyperopia – hyperopia produced by the normal biological variation of the refractive components of the eye Pathological hyperopia – hyperopia resulting from abnormal conditions of the eye Examples: Microphthalmos lens at all Aphakia no uncorreyed + 15 Ectopia lentis Zohules not Strength - Marfan syndrome 10 Hypermetropia (Hyperopia) Low hyperopia: ≤ +2.00 D Moderate hyperopia: +2.25 to +5.00 D High hyperopia: > +5.00 D Hypermetropia (Hyperopia) Absolute hyperopia – the portion of hyperopia that cannot be compensated for by accommodation minimum we ent Manifest hyperopia – the portion of total hyperopia measured by the relaxation of accommodation during dry refraction maximum accepted Total hyperopia – the hyperopia that results when the ciliary muscle is completely relaxed (wet refraction) Manifest + latent hyperopia Latent hyperopia – the portion of total hyperopia compensated for by accommodation 11 Example 28 year old female with asthenopia has entering acuity of 20/50 +1.00 DS improves vision to 20/20 Absolute hyperopia Takes additional +1.50 DS in dry refraction Manifest hyperopia to maintain 20/20 Requires +3.50 DS to see 20/20 with wet refraction Total hyperopia (Cycloplegia revealed that there was +1.00 D of… latent hyperopia ) Myopia The image is formed in front of the retina with accommodation at rest Night myopia – myopia (or an increase in myopia) occurring in low levels of illumination Empty space myopia – myopia (or an increase in myopia) "Clouds" occurring in the absence of optical stimuli to e exelofcsead "lots so of accommodation Pseudomyopia – the refractive condition of myopia attributable to spasm of the ciliary muscle or incomplete spasmeventing relax relaxation of accommodation ⑦ ability - to them from NRA relaxing E NRA low DRA 12 Myopia Low myopia: < -1.50 D Moderate myopia: -1.50 D to -6.00 D High myopia: > -6.00 D or more Myopia Congenital myopia – presents throughout infancy and is present upon entering school Pathological (degenerative) myopia – axial length elongation that causes structural changes in internal structures; associated with pathology including Retinal tears, detachment and lesions Chorioretinal atrophy Cataracts Glaucoma Posterior staphyloma Macular hole 13