Examination of the patient with decreased vision requires performing a full neuro-ophthalmic evaluation.
Visual Acuity Testing
Corrected distance visual acuity (CDVA; also called best-corrected visual acuity) should be obtained with refraction. Vision improvement with pinhole viewing indicates a refractive error. For patients with visual acuity levels worse than 20/400, the clinician should quantify CDVA using a standard 20/200 E optotype chart. The clinician records the distance at which the patient is able to discern the letter orientation using standard Snellen notation (eg, “5/200”). This test provides a more accurate and reproducible measurement than does the finger-counting method.
Distance and near corrected visual acuity should be similar; a disparity may suggest a specific pathology. The clinician should document the presence of eccentric fixation (possible central scotoma), tendency to read half of the eye chart (possible hemianopic field defect), or improvement in CDVA when reading single optotypes (which may suggest amblyopia).
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.