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Effect of contralateral fog during refractive error assessment
N N Chiu1, M Rosenfield, L C Wong
1State University of New York, State College of Optometry, New York 10010, USA.
Journal of the American Optometric Association
|May 1, 1997
Summary
Higher amounts of contralateral fog during refractive error assessment using static retinoscopy cause minimal and clinically insignificant changes in the refractive state. Ensuring the nontested eye is fogged is key, as fog magnitude has little effect.
Area of Science:
- Ophthalmology
- Optometry
- Vision Science
Background:
- Conventional static retinoscopy involves fogging the fellow eye to prevent accommodative responses.
- The impact of higher levels of contralateral fog, especially in myopic individuals, remains unclear.
Purpose of the Study:
- To investigate the effect of increasing contralateral eye fog on refractive state measurements during static retinoscopy.
- To determine if higher fog levels significantly alter objective refractive error assessment.
Main Methods:
- Objective refractive state was measured in 16 myopic subjects using simulated streak retinoscopy.
- Contralateral eye fog was systematically increased from 0 to 6.00 D in 1.00 D steps.
Main Results:
- No significant changes in refractive state were observed with up to 5.00 D of contralateral fog.
- 6.00 D of contralateral fog induced a small, significant myopic shift (0.13 D mean).
- Largest observed shifts were clinically insignificant and within the repeatability limits of static retinoscopy.
Conclusions:
- Large amounts of contralateral fog in static retinoscopy produce minimal and clinically insignificant changes in refractive state.
- Practitioners should ensure the fellow eye is adequately fogged, but the precise magnitude of fog has limited impact.
- These findings support current retinoscopic practices regarding contralateral eye fogging.