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.