Oculomotor Diagnosis 1 & 2 Lecture 2 PDF

Oculomotor Diagnosis 1 M.H. ESTHER HAN, OD, FCOVD, FAAO, Dipl ABO ASSOCIATE CLINICAL PROFESSOR AVSF I – SPRING 2024 JANUARY 12, 2024 1 Readings: Oculomotor Diagnosis ▶ Scheiman and Wick: Clinical management of binocular vision: heterophoric, accommodative, and eye movement disorders, 5th edition...

Oculomotor Diagnosis 1 M.H. ESTHER HAN, OD, FCOVD, FAAO, Dipl ABO ASSOCIATE CLINICAL PROFESSOR AVSF I – SPRING 2024 JANUARY 12, 2024 1 Readings: Oculomotor Diagnosis ▶ Scheiman and Wick: Clinical management of binocular vision: heterophoric, accommodative, and eye movement disorders, 5th edition - 2020 ▶ Pages: 24-31*** ▶ Pages: 345-353 ▶ Pages: 460-471 OR ▶ Scheiman and Wick: Clinical management of binocular vision: heterophoric, accommodative, and eye movement disorders, 4th edition - 2014 ▶ Pages: 25-32*** ▶ Pages: 368-376 ▶ Pages: 491-504 ***Mandatory -required readings 2 Readings: Oculomotor Diagnosis ▶ Scheiman and Rouse: Optometric Management of Learning-Related Vision Problems, Second Edition – 2006 ▶ ▶ Pages: 38-43 Ciuffreda and Tannen: Eye movement basics for the clinician – 1995 ▶ Pages: 1-2; 10-32; 161-164; 206-222 ▶ Wong: Eye Movement Disorders – 2008 ▶ Chapters 7, 8 ▶ Duckman. Visual development, diagnosis, and treatment of the pediatric patient, 2nd edition - 2020 ▶ Pages: Chapter 18 (pages 336-353) ***Mandatory 3 4 Objective: Since patients (including children) have symptoms of loss of place or dizziness, we need to understand how to manage these patients. OCULOMOTOR DIAGNOSIS LECTURE 1 ▶ How do we recognize a patient who has an oculomotor (versional) dysfunction? ▶ Is nystagmus an oculomotor (versional) problem? ▶ What are the types of oculomotor problems a patient can come in with? 5 Outline for Oculomotor Diagnosis ▶ Types of oculomotor (versional) disorders ▶ Prevalence rates ▶ Neurology of eye movements development ▶ Version and ▶ Clinical tools for diagnosis ▶ Version disorders and systemic disease 6 How do we recognize a patient who has an oculomotor (versional) dysfunction? ▶ Kevin, an 8-year-old (third grader) was referred by their reading tutor. ▶ The tutor was concerned because she had observed frequent loss of place, skipping of lines, inability to sustain attention for the reading task, and poor comprehension. ▶ She wanted to rule out a vision problem as a possible cause of these behaviors. -reading to learn but child is having problems -kevin can’t move forward due to ocular-motor problems 7 How do we recognize a patient who has an oculomotor (versional) dysfunction? ▶ Kevin did not report any symptoms of eyestrain, blur, or diplopia (double vision). ▶ Academically, he was experiencing difficulty, primarily in the area of reading. The reading problems had been present to some degree since the first grade, although the problems appeared worse this year. Although his sight vocabulary and phonic skills were average to above average, he consistently scored poorly on comprehension tests. In addition, his reading speed was significantly less than expected. ▶ Because of these difficulties, his parents had initiated work with the reading tutor. 8 How do we recognize a patient who has an oculomotor (versional) dysfunction? ▶ After several weeks of working with Kevin, the tutor suggested the vision therapy evaluation because of her observations. ▶ A recent medical evaluation revealed normal health, and he was not on any medications. 9 -yes 10 Oculomotor (Versional) Terminology 11 Different terminology ▶ Version: conjugate movement of the eyes; movement of the eyes in the SAME direction to see objects*** NON-CONJUGATE EYE MOVEMENT CONJUGATE EYE MOVEMENT -both eyes move in the same direction of the object -convergence is a non-conjugate movement 12 Different terminology or ocular motor dysfunction: Refers to the condition in which there are problems in ALL areas of eye movement function; i.e. fixation, saccades, pursuit ▶ Oculomotor ▶ Note: Some texts or lecturers/scientists will include vergence eye movements as well but not in this course. NBEO does this. 13 Types of versional eye movements *know these for this course TYPE STIMULUS FUNCTION FIXATIONAL* STATIONARY To stabilize a target on the fovea. SACCADIC* STEP DISPLACEMENT (voluntary) To acquire an eccentric target onto the fovea. PURSUIT* TARGET VELOCITY (stimulus-generated) To match eye velocity with target velocity to stabilize the retinal image. READING EYE MOVEMENTS * OPTOKINETIC Text To read VESTIBULAR (VOR) TARGET OR FIELD VELOCITY To maintain a stable image during sustained head movement. HEAD ACCELERATION To maintain a stable image with the target on the fovea during the initial and transient head movement. 14 Fixation…. More complex than we think. 15 Fixation… ▶ During steady fixation, the eye does NOT remain perfectly motionless. ▶ Both SLOW and RAPID small-amplitude eye movements occur. ▶ The image remains within the “functional” fovea (+/30 min of arc). ▶But is more typically concentrated within a few min of arc from the central fovea. -there is always a slow natural movement so that the image remains on fovea 16 Gaze Stability Considerations ▶ Head movements of 0.75 degrees may occur ▶ This will decrease GAZE STABILITY, and this will increase RETINALIMAGE MOTION. ▶NORMALS: This increased retinal motion is generally BELOW the threshold and will not adversely affect visual acuity. -understand that there is always slight head and eye movement 17 Fixation Characteristics… ▶ Fixation away from primary gaze affects fixation accuracy. ▶ No major difference between monocular and binocular viewing conditions. ▶ Stability of fixation: No age-related changes ▶ Range of fixation: With elevation or upward gaze does decrease with advancing age. -will age effect fixation and the answer is NO! 18 Fixation and visual feedback… Consideration for VT ▶ Visual feedback greatly enhances the accuracy of fixation… Important point for VT. ▶ In the absence of visual feedback, saccades are seen to attempt to re-center the eye towards the “remembered” target position. ▶ Proprioception information ▶ Tactile information: cornea, lids, and surrounding tissue provide “extra-retinal” signals for eye movement control. -feedback is impt for fixation to allow pt to remember where to look at the target 19 OCULOMOTOR DIAGNOSIS: Part 2 M.H. ESTHER HAN, OD, FCOVD, FAAO, Dipl ABO ASSOCIATE CLINICAL PROFESSOR AVSF 1 –SPRING 2024 JANUARY 19, 2024 20 21 -answer: D 22 Objective: Since oculomotor (saccadic and pursuit) skills are important for school-age children, we need to understand what oculomotor or eye tracking skills are needed for adequate oculomotor function. OCULOMOTOR DIAGNOSIS ▶ What are the specific skills needed for good oculomotor function? ▶ What are the characteristics of oculomotor skills during development? What type of oculomotor skills should be we expect when we evaluate them? How is the development of oculomotor skills different from accommodative/vergence skills development? ▶ Where in the brain is oculomotor function located? ▶ How do we evaluate for deficits of fixation, saccades, pursuit, and reading eye movements in clinic? 23 Case Example… Oculomotor Deficits Remember… Subjective Objective Assessment Plan 24 Entering symptoms: 12 yo Male • • • • Case Behran: Subjective Skips lines Sees double Re-reads same line Every now and then loses place while looking at the board • Headaches every day on forehead; happens after school • Reports he is good at sports • Mom reports sometimes he bumps into things Pertinent History: • C urrently in 6th grade; had to repeat 3rd grade • (+) ADHD • NICU x 9 days when born; lungs were not fully developed LAUNCH POLL EVERYWHERE 25 -he repeated third grade 26 Types of versional eye movements *know these for this course TYPE STIMULUS FUNCTION FIXATIONAL* STATIONARY To stabilize a target on the fovea. SACCADIC* STEP DISPLACEMENT (voluntary) To acquire an eccentric target onto the fovea. PURSUIT* TARGET VELOCITY (stimulus-generated) To match eye velocity with target velocity to stabilize the retinal image. READING EYE MOVEMENTS * OPTOKINETIC Text To read VESTIBULAR (VOR) TARGET OR FIELD VELOCITY To maintain a stable image during sustained head movement. HEAD ACCELERATION To maintain a stable image with the target on the fovea during the initial and transient head movement. 27 -pt looking at a marsan ball horizontally moving back and forth -left esotropia with a slight nystagmus looking to the left -pt is suppressing one eye so that’s why he doesn’t see double 28 My patient Daniel… ▶ Imet Daniel when he was 10 years old… ▶ Chief Complaint: h/o longstanding constant esotropia OS presents for strabismus VT evaluation. Patient's mother would like to pursue vision therapy because she is concerned about the patient's depth perception and eye teaming ability due to his history of an eye turn Mother reports that they put the patient in a basketball program that meets several times per week to help stimulate his depth perception and coordination. She noticed a big difference when patient was not in this program over the summer, and he started bumping into objects more and seemed to struggle with his peripheral vision. These skills seemed to improve when patient was placed back in the basketball program in the fall. In the end, mother is mainly interested in maximizing the patient's visual potential and promotion spatial awareness and depth perception. Patient denies diplopia, headaches, eyestrain, or blurred vision. 29 Eye movements during fixation… Tremor: Drift: Microsaccade: Error producing Error producing Error correcting 30 During normal fixation: Tremor ▶ Represents the “noise” in the oculomotor system ▶ Error produced does not affect VA or retinal error. ▶ Not correlated between the two eyes. 31 During normal fixation: Drift ▶ Movement Hz) is irregular and of a variable low frequency (<0.5 ▶ Hertz (Hz): number ▶ Drift makes up of oscillations or cycles per second) more than 95%of one’s fixation time. ▶ Not correlated between the two eyes. ▶ Also believed to be “noise” in the oculomotor system and therefore error producing. 32 During normal fixation: Microsaccade ▶ Frequency ▶ Large of 1-2 saccades per second dynamic overshoot component ▶ Always BINOCULAR and has a high amplitude correlation between the two eyes. This suggests that they are under central (CNS) neurological control. ▶ Believed to be error correcting: drift-induced position errors are reduced and will re-center the fovea. -when both eyes are involved and move at the same time à it is under neurological system -this is under normal eye movement -tremor and drift are error producing while microsaccades are error correcting 33 Fixation Eye Movements Demo… • • Drift: slow movements Microsaccades: rapid jerky movements 34