Intro to Binocular Vision Treatment

single, clear comfortable, binocular vision, cosmesis

The goal of visual treatment is ____. If this is not obtainable, _____ is of concern

absence of sensory fusion

asymptomatic heterophoria

monofixation syndrome

three examples of binocular vision cases that may not require any treatment

divergence, exo

Over minusing a patient can be used to correct a ____ excess ____

convergence, eso

Over plusing a patient can be used to correct a ____ excess ____

latent hyperope

a Patient may be under plused if they are a....

5

Place the bifocal segment height at the mid pupil for children under ____ years old

6-7

Place the bifocal segment height at the pupil margin for children ____ years old

8

Place the bifocal segment height at the lower lid margin for children above ___ years old

4

A PAL segment height should be placed ____ mm above the mid pupil in young patients

base, apex

Light bends towards the prism's ____ displacing the image towards the prism's ____

Relieving prisms

prescribed prisms that have a power that is less than the ocular deviation. Function to reduce fusional vergence demand.

Corrective prisms

prescribed prisms that have a power that is equal to the ocular deviation. Function to eliminate fusional vergence demand. Are most effective for a recent onset deviations that will not resolve voluntarily.

Over corrective prisms

prescribed prisms that have a power that is more than the ocular deviation (usually by about 10 PD). Function to enhance diplopia awareness as an anti-suppression technique or disruption of anomalous correspondence.

Inverse prisms

prescribed prisms that increase the compensating vergence range. Function as a passive therapy to improve fusional vergence ability.

Yoked prisms

prescribed prisms that have their bases and apexes oriented in the same direction in order to shift the visual system. Can be used to move the null point of nystagmus to central gaze, correct head posture, or shift image in patients having hemianopsia or midline shift syndrome.

Rotating prisms

prescribed 10 PD Fresnel prism whose base direction is rotated weekly.

Regional prisms

prescribe Fresnel prism that is applied only to parts of a lens. Is useful in non-comitant deviation eliminating diplopia in certain gazes.

5

Ground in prism >___ PD has cosmetic concerns and this should be explained to the patient

Prism adaptation

occurs when prism is prescribed to correct an eye posture. Cover test results then match precious sc results, but now with prismatic correction. The sc cover test results then reveal a larger phoria than initially measured. Most commonly occurs in patients having anomalous correspondence. Rarely occurs in standard heterophores. If this occurs remove prism correction and improve visual skills with VT.

4-6 PD

residual vergence demand criterion for an eso deviation

10-15 PD

residual vergence demand criterion for an exo deviation

2-4 PD

residual vergence demand criterion for a hyper deviation

(2xphoria-compensating vergence reserve)/3

Sheard's criterion

(greater limit BI or BO) - 2(lesser limit BI or BO)/3

Percival's criterion

Associated phoria

the amount of prism required to reduce fixation disparity (small misalignment of the visual axis under binocular conditions) to zero.

Treat amblyopia

Differentiate monocular versus binocular causes

Disrupt sensory anomalies

three goals of occlusion therapy

direct occlusion

occlusion treatment involving patching the better seeing eye. Breaks down binocularity. Can be used to temporarily treat diplopia or to treat amblyopia.

inverse occlusion

occlusion treatment involving patching the amblyopic eye in order to disrupt steady eccentric fixation. Poses a risk of inducing amblyopia and is therefore not commonly done in practice.

alternating occlusion

occlusion treatment involving full time occlusion that is alternated daily between the two eyes. Is used to promote alternation of a constant unilateral strabismus or to disrupt other sensory anomalies (AC, suppression). Not commonly done in practice.

partial occlusion

occlusion treatment used to eliminate diplopia in certain gazes. Binasal for esotropia, bitemporal for exotropia may be used in order to promote alternation. Bitemporal occlusion is less accepted due to reduction of peripheral vision.

Occlusion amblyopia

induced amblyopia due to prolonged patching which can occur when the amblyopic eye is patched, or when the preferred eye is patched for too long.

Strabismic diplopia

diplopia occurring after suppression or anomalous correspondence is eliminated and the patient lacks the ability to fuse under these conditions. Is resolvable with prism if motor fusion is lacking. Is unresolvable if sensory fusion is lacking.

Vision therapy (orthoptics, visual training)

a sequence of neurosensory and neuromuscular activities individually prescribed and monitored in order to develop, rehabilitate, and enhance visual skills and processing.

Sensory fusion

the combination of two images seen by the two eyes into a single unitary percept

Motor fusion

the relative movement of the two eyes in order to maintain sensory fusion.

Convergence insufficiency

the only binocular vision condition that will warrant payment by insurance for vision therapy

esotropes

Maximize plus for...

exotropes

Minimize plus for...

vision therapy

plus

primary and secondary treatment for ocular motor dysfunction

plus

vision therapy

primary and secondary treatment for accommodative insufficiency

plus

vision therapy

primary and secondary treatment for ill sustained accommodation

vision therapy

primary and secondary treatment for accommodative excess

vision therapy

primary and secondary treatment for accommodative infacility

vision therapy

prism

primary and secondary treatment for convergence insufficiency

prism

vision therapy

primary and secondary treatment for divergence insufficiency

plus

vision therapy

primary and secondary treatment for convergence excess

vision therapy

over minus

primary and secondary treatment for divergence excess

vision therapy, plus lenses

prism

primary and secondary treatment for basic eso

vision therapy

over minus, prism

primary and secondary treatment for basic exo

vision therapy

primary and secondary treatment for fusional vergence dysfunction

prism

vision therapy

primary and secondary treatment for vertical phoria