3.2 Core Workflows and Decision Points

3.2 Core Workflows and Decision Points

Visual Assessment questions reward the technician who chooses the right chart and technique for the patient in front of them. Memorizing one routine is not enough; the COA must adapt for distance vs near, literate vs pre-literate, and refractive vs pathologic findings.

Distance vs near acuity

Distance VA is taken at 20 feet with the Snellen chart or the research-grade ETDRS (Early Treatment Diabetic Retinopathy Study) logMAR chart. Near VA is taken with a handheld card held at the patient's normal reading distance, conventionally 14-16 inches (35-40 cm). Always record the near distance used, because changing it changes the result.

The Jaeger scale runs J1 (smallest) up through J10+ (largest). J1 is roughly the near equivalent of 20/20. Presbyopic patients over ~40 will need their reading add to reach J1 at near, so always test near VA with the reading correction in place.

The pinhole occluder

The pinhole occluder is a disc with a 1.0-2.4 mm aperture. It admits only the central, paraxial rays, so it bypasses most refractive blur. Interpretation is high-yield:

• VA improves with pinhole → the deficit is refractive (the patient needs glasses or an updated prescription).
• VA does not improve (or worsens) → suspect a non-refractive cause: cataract or other media opacity, macular disease, or optic-nerve pathology.

Use the pinhole whenever uncorrected VA is worse than 20/30 and no current refraction is available. Record it as, for example, "ph OD 20/25."

Occlusion technique

Test OD first, then OS, completely occluding the non-tested eye with an opaque occluder or the patient's palm cupped (never pressing on the globe, which blurs the next reading). Never let the patient peek; covering with fingers that have gaps is a classic real-world error the exam may describe.

Pediatric and non-verbal patients

Letter charts assume literacy. For children or non-readers, step down this ladder by developmental age:

1. Fixation behavior / CSM (central, steady, maintained) in infants
2. Teller / preferential-looking cards in pre-verbal infants
3. LEA symbols or Allen pictures (apple, house, circle) in toddlers
4. HOTV matching test in young children
5. Tumbling-E chart for children who know directions but not letters

For every population, the COA's job is the same: obtain a reliable, reproducible acuity and document the method, distance, correction, and any cooperation issues so the physician can interpret it correctly.

A reproducible distance-acuity routine

A defensible distance-VA workflow runs the same way every time. Seat the patient at the calibrated distance, confirm room lighting is even and the chart is fully illuminated, and ask whether they normally wear glasses for distance. Test OD first with the left eye fully occluded, then OS, then OU if needed, and finish with the pinhole on any eye worse than about 20/30. Encourage the patient to read the next smaller line even if they think they cannot, because guessing recovers letters and yields a truer endpoint.

Stop at the smallest line where the majority of optotypes are correct, and note any partial letters with the plus/minus convention. Record the correction state explicitly so the next reader knows whether the value was sc, cc, or ph.

Reading the result clinically

The sequence of values tells a story. If uncorrected acuity is poor but corrected or pinhole acuity is good, the eye is healthy and simply needs the right lens. If corrected and pinhole acuity stay poor, an optical fix will not help and the physician must look for disease. A large discrepancy between the two eyes, a value that fails to improve with the patient's own current glasses, or a drop from a prior visit are all findings worth highlighting in your note. The COA does not diagnose, but organizing the acuity data so the pattern is visible is part of competent technician work and is exactly what scenario questions reward.

Documentation discipline

Every acuity entry should be self-explanatory months later: eye, correction, distance if non-standard, the value, and any caveats such as poor cooperation, a patched fellow eye, or dim lighting. A bare "20/40" without context invites misinterpretation. When in doubt, write more, not less, because the chart is the legal record of the encounter and the basis for the physician's plan.

Choosing the correction to test

A recurring decision point is which lenses to test through. The general rule is to record both uncorrected (sc) and best-corrected or habitual-corrected (cc) acuity at the first visit, because the physician needs to know both how the patient sees naturally and how well they can be corrected. Test distance acuity through the patient's distance prescription and near acuity through the near (reading) add, never the reverse. If the patient brings progressive or bifocal lenses, use the distance portion for the 20-foot chart and the reading segment for the near card.

Document exactly which glasses were worn, since "cc" is meaningless if the chart does not say with what.