DEFINITIONS (of conditions often associated with nystagmus)

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Transcript DEFINITIONS (of conditions often associated with nystagmus)

Vicki Leung, O.D.

23161 Ventura Blvd, Suite 201 Woodland Hills, CA (818) 591-8860 [email protected]

The Optometric Examination

 Visual Acuity

Measuring Visual Acuity

 Whole Chart – Standard E S L T O Z B P L O D F G A D A O S E G N U S F Z B D R

Measuring Visual Acuity

 Line T O Z F Z B D R D E F O A E

Measuring Visual Acuity

 Letter F G E A

The Optometric Examination

 Basic Binocular Vision Testing – Cover Test – – Near Point of Convergence Stereopsis If Strabismus is present, a Strabismus Evaluation is indicated and should be performed by an eye doctor who evaluates and treats strabismus patients.

The Optometric Examination

 Refraction – Objective methods: Retinoscopy and auto refraction – Subjective methods: Interactive with the patient, “Which is better, one or two?” Nystagmus patients may have high amounts of astigmatism that can go uncorrected. It is important to correct it.

The Optometric Examination

 Eye Health Examination External Eye Examination Internal Eye Examination

Treatment of Idiopathic, Congenital Nystagmus

The comprehensive management for the nystagmus patient should include treatment of all associated conditions, as well as improve the characteristics of the nystagmus wave form.

Considerations for treatment: 1.

Proper refraction and full correction Glasses Prisms Contact Lenses

Treatment of Idiopathic, Congenital Nystagmus

2. Addressing binocular vision concerns Glasses Prisms Contact lenses Vision therapy

Treatment of Idiopathic, Congenital Nystagmus

3. Surgery Strabismus Surgery Nystagmus dampening surgery

Treatment of Idiopathic, Congenital Nystagmus

4. Vision Therapy - The Goal of Vision Therapy is not to dampen the nystagmus, but rather to improve visual acuity.

DEFINITIONS

ASTIGMATISM

A refractive condition in which light rays do not focus at a single point, rather focus at 2 lines. Therefore, it requires 2 separate powers to bring both lines in focus to a single point.

AMBLYOPIA

Any eye that doesn’t see 20/20, or for certain cases, a difference between eyes that is greater than 2 lines of acuity.

LAZY EYE

Laypersons term for amblyopia but many mistakenly use it to describe an eye turn.

DEFINITIONS

STRABISMUS

Any eye turn, in or out, up or down, intermittent or constant. Can have a combination of directions (i.e. in and up) – – –

ESOTROPIA

turn.

- Right or left eye turning inward (or alternating between eyes), can be a constant or intermittent

EXOTROPIA

turn.

- Right or left eye turning outward (or alternating between eyes), can be a constant or intermittent

HYPERTROPIA

– Right or left eye turning upward.

DEFINITIONS

DEPTH PERCEPTION

Perception of relative or absolute difference in distance of objects from the observer. Can occur with or without binocular vision. Perception of a third dimension.

STEREOPSIS

Binocular

visual perception of three dimensional space, based on retinal disparity.

BINOCULAR VISION

Pertaining to using both eyes simultaneously, so that each eye contributes to the image seen.

VISION THERAPY / ORTHOPTICS

The teaching and training process to improve visual perception and coordination of the 2 eyes. Goals include improving visual acuity, elimination of strabismus, comfortable binocular vision.

Vision Therapy

 Traditional Vision Therapy (can be done both at home and at the doctor’s office) – Fusional Vergence Training – Anti-suppression Training  Brock String  Tranaglyph  R/G trainers – Accommodation (focusing) Training

Vision Therapy

 Foveation Tasks – Vertical line counting (may start at oblique angles)

Vision Therapy

Vision Therapy

 Foveation Tasks – Letter Counting Tasks

Vision Therapy

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Conclusions

 Home Vision Therapy can be used to supplement or replace office-based therapy.

 Home VT is designed to address binocular vision deficiencies as well as increase foveation, which generally leads to increased visual acuity.

 A decrease in amplitude , frequency or intensity of the nystagmus does not necessarily lead to increased visual acuity.

Conclusions

 Patients report successful treatment based on improved quality and comfort of vision.

 Subjective improvement seems to be greater than the measured visual acuity.