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Subjective refraction
Anatomy & Optics
Key Points
- •Fogging technique relaxes accommodation by adding excess plus; reduce in −0.25 steps to find the most plus for best VA
- •Duochrome test: Red clearer → add plus (RAF); green clearer → add minus; equal = correct refraction. Invalid in colour-blind patients.
- •JCC axis refinement: handle at axis → flip → rotate axis 5° towards JCC minus axis in preferred position
- •JCC power refinement: JCC minus axis at cylinder axis → flip → add/remove −0.25 DC (with compensating sphere) based on preference
- •Binocular balancing equalises accommodation between eyes - essential before finalising the prescription
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17 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Risk factors and associations