Refractometry
Retinoscopy and subjective refinement — cross cylinder, balancing, and cycloplegic refractions.
Retinoscopy: Working-Distance Arithmetic and Reading the Reflex
Retinoscopy is the objective half of the refraction, and at technician level you are expected to produce a usable starting point on a patient who cannot answer questions at all. Everything rests on two skills: getting the arithmetic right, and reading what the reflex is telling you.
The working-distance correction. Your own eye sits at a finite distance from the patient, so the neutrality point you find is the refraction for that distance, not for infinity. The correction is simply the reciprocal of the working distance in meters, and it is subtracted from the gross finding.
In the full COT guide
- Retinoscopy: Working-Distance Arithmetic and Reading the Reflex
- Artifacts, Difficult Media, and What the Reflex Reveals
- Cycloplegia and Controlling Accommodation
- Subjective Refinement, the Near Add, and the Instruments
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