Near Retinoscopy, Subjective & Binocular
Refraction, Phoropter
Learning Objectives
● List indications for near retinoscopy.
● Explain and perform the Mohindra Technique for near retinoscopy.
● Interpret near retinoscopy findings, applying correction factors and working distance
adjustments.
● Discuss assumptions, problems, and sources of error in near retinoscopy.
● Apply subjective refraction methods to determine an accurate, balanced endpoint.
● Evaluate when to perform binocular refraction and understand phoropter vs. trial
frame use.
1. Near Retinoscopy (Mohindra Technique)
Overview
● Variation of static retinoscopy, mainly for infants/young children.
● Allows refractive error estimation without cycloplegia.
● Distance target fixation often not possible in children.
● Safer alternative when:
○ Cycloplegia is not
○ tolerated.
○ Previous adverse reaction to cyclopentolate.
○ Requires frequent follow-ups.
○ Parent or guardian do not consent to cycloplegia
Principle
● Determines refractive error under controlled accommodation.
● Done in darkness → removes accommodative stimulus.
● Tonic accommodation (~+0.75D) still present → must be corrected. - rx will appear
less positive/ more negative
, Correction Factor
● Near retinoscopy differs by ≈ –0.75D from standard distance retinoscopy.
● Add +0.75D correction factor (for tonic accommodation).
● Add +2.00D for 50cm working distance → total +1.25D adjustment.
○ Example: –2.00D (at 50cm) → –2.00 + 1.25 = –0.75D final result.
Procedure
1. Set-up:
○ Patient faces practitioner (child may sit on parent’s lap).
○ No phoropter/trial frame.
○ Room must be completely dark.
2. Testing:
○ Direct attention to retinoscope light.
○ Scope along major meridians; neutralise movements.
- Using sphere - sphere
○ Use lens rack for infants.
3. Calculation:
○ Transpose result into minus cylinder form.
○ Subtract +1.25D from result for final distance Rx.
Performing the technique:
● On a young child, neutralise the two meridians separately
● Record as sphero-cyl
● Horizontal slit +1.00 (scoping vertical)
● Vertical slit +1.50 (scoping horizontally)
Examples
● Emmetrope: Appears myopic by 0.75D (due to tonic accommodation).
● Hyperope: May be underestimated due to closer tonic accommodation.
● Myope: Result closer to true value.
Assumptions
Refraction, Phoropter
Learning Objectives
● List indications for near retinoscopy.
● Explain and perform the Mohindra Technique for near retinoscopy.
● Interpret near retinoscopy findings, applying correction factors and working distance
adjustments.
● Discuss assumptions, problems, and sources of error in near retinoscopy.
● Apply subjective refraction methods to determine an accurate, balanced endpoint.
● Evaluate when to perform binocular refraction and understand phoropter vs. trial
frame use.
1. Near Retinoscopy (Mohindra Technique)
Overview
● Variation of static retinoscopy, mainly for infants/young children.
● Allows refractive error estimation without cycloplegia.
● Distance target fixation often not possible in children.
● Safer alternative when:
○ Cycloplegia is not
○ tolerated.
○ Previous adverse reaction to cyclopentolate.
○ Requires frequent follow-ups.
○ Parent or guardian do not consent to cycloplegia
Principle
● Determines refractive error under controlled accommodation.
● Done in darkness → removes accommodative stimulus.
● Tonic accommodation (~+0.75D) still present → must be corrected. - rx will appear
less positive/ more negative
, Correction Factor
● Near retinoscopy differs by ≈ –0.75D from standard distance retinoscopy.
● Add +0.75D correction factor (for tonic accommodation).
● Add +2.00D for 50cm working distance → total +1.25D adjustment.
○ Example: –2.00D (at 50cm) → –2.00 + 1.25 = –0.75D final result.
Procedure
1. Set-up:
○ Patient faces practitioner (child may sit on parent’s lap).
○ No phoropter/trial frame.
○ Room must be completely dark.
2. Testing:
○ Direct attention to retinoscope light.
○ Scope along major meridians; neutralise movements.
- Using sphere - sphere
○ Use lens rack for infants.
3. Calculation:
○ Transpose result into minus cylinder form.
○ Subtract +1.25D from result for final distance Rx.
Performing the technique:
● On a young child, neutralise the two meridians separately
● Record as sphero-cyl
● Horizontal slit +1.00 (scoping vertical)
● Vertical slit +1.50 (scoping horizontally)
Examples
● Emmetrope: Appears myopic by 0.75D (due to tonic accommodation).
● Hyperope: May be underestimated due to closer tonic accommodation.
● Myope: Result closer to true value.
Assumptions
