Binocular Refraction I

What are the advantages of binocular refraction in comparison to monocular refraction and binocular balancing ?

• greater relaxation of accommodation

• light adaptation equal

• eye is in a more ‘normal’ situation that when one eye occluded (care must be taken the cyl axis is not incorrect as this will create unnatural visual axis)

• can be slightly quicker than monocular refraction, because no binocular balancing required

• in latent nystagmus patient, occlusion in monocular refraction may cause nystagmus to manifest

what patients is binocular refraction ideal for?

• latent hypermetropes → hypertrope who is constantly accommodating

• Pseudomyopes →accommodation spasm, but present as myope

• Latent nystagmus →if you occlude could make vision worse

What are the contraindications to subjective binocular refraction?

• patients who don’t have binocular vision

What is the procedure for Subjective Binocular refraction?

• with ret result in place measure VA

• occlude right eye + blur left eye using +0.75DS or +1.00DS → check vision blurred 3 or 4 lines on chart & remove occluder

• Find BVS and then check cyl axis and power using JCC method

• use duo chrome to determine the best sphere endpoint

• Measure + record VA

• Remove fogging lens in left eye + place in front of right eye

• Find BVS for left eye + check cyl axis and power using JCC method → use duochrome to determine end result sphere

• Measure VA and then record