Visual acuity software

Visual acuity software is clinical software that displays calibrated eye charts — Snellen, ETDRS/LogMAR, pediatric optotypes and related tests — on a monitor, tablet or wall display instead of a chart projector or printed chart. Optotype sizes are calculated from the patient-to-screen distance the clinician enters, letters can be randomized between presentations, and a single system replaces a cabinet of physical charts. It is used in ophthalmology and optometry practices by physicians, optometrists, technicians and orthoptists.

Last updated: August 20, 2026

One category, several names

The same software is searched for under many names: visual acuity software, digital eye chart, computerized eye chart, electronic eye chart, Snellen chart software, eye chart software, and acuity testing system. These are not different products — they are the same category seen from different starting points. The clinical distinction that actually matters is calibration: a consumer “eye chart app” that does not calculate optotype size from a verified testing distance is a toy, not an instrument. For the full picture of how digital testing works clinically, see our guide to digital visual acuity testing.

What it replaces, and why practices switch

Most practices adopting acuity software are replacing one of two things: a chart projector (bulbs burn out, mirrors drift, the chart set is fixed at whatever slides shipped with it) or printed wall charts (patients memorize them, and one chart is one test). The trade-offs are covered honestly in digital eye chart vs. projector — including the cases where a working projector is still fine to keep.

The clinical features that separate systems

The chart set

• Snellen — the everyday clinical chart, in US, metric or decimal notation.
• ETDRS / LogMAR — five letters per row, equal spacing, LogMAR scoring; the standard for clinical trials and for tracking change over time. The two chart families disagree systematically on the same eye — Snellen vs. ETDRS explains why.
• Pediatric optotypes — HOTV, Tumbling E, Landolt C and picture optotypes, with crowding bars for amblyopia work. See the pediatric optotypes guide.
• Binocular and refraction-support tests — Worth 4-Dot, fixation disparity, astigmatic dial, red-green duochrome.
• Color vision screening and reduced-contrast optotypes. Vendors differ genuinely here: some systems offer scored contrast-sensitivity testing; others (including AcuityMaster) offer reduced-contrast acuity at fixed contrast levels, which is a different measurement.

Calibration and display discipline

Optotype size must be computed from the actual patient-to-screen distance, and the display must be bright enough: the ANSI Z80.21 standard calls for a background luminance of 80–320 cd/m², which most modern LCD monitors can produce but which depends on the monitor and its settings, not on the software. Randomized letter presentation prevents memorization; single-letter, single-line and multiline modes support different testing styles; mirror mode halves the physical distance a compact lane needs. Setup discipline matters as much as the software — our digital eye chart setup guide covers verification steps and re-check schedules.

Delivery model

How to choose — five questions that settle it

• Does it run on the hardware you already have? Platform is the fastest filter: several systems are Windows-only, and a Mac or iPad practice narrows the field quickly. See Mac and iPad specifics.
• Does the chart set cover your caseload? A heavy pediatric or binocular-vision caseload needs crowding bars, picture optotypes and Worth 4-Dot; a clinical-trial site needs ETDRS.
• Is the pricing published? Some vendors publish prices; others quote per conversation. A published price is checkable; a quote is not. Our comparison table marks “quote only” wherever a vendor publishes nothing.
• Can you trial the real product? A full-featured trial on your own hardware, with your own patients, answers questions no comparison page can.
• What happens when a workstation dies? Per-computer licenses can mean transfers and re-activation; browser-based seats follow the sign-in, not the machine.

Where AcuityMaster fits

AcuityMaster Cloud is the browser-based entry in this category: it runs in Safari, Chrome, Firefox or Edge on Mac, Windows or iPad with no installation, provides Snellen, ETDRS/LogMAR, color vision, reduced-contrast, Worth 4-Dot and pediatric charts, is designed to ANSI Z80.21 and ISO 8596, and publishes its pricing in full — $249 per year for a first seat, with graduated band rates above that. The 7-day free trial needs no credit card. It is not the right fit for every practice — the alternatives page lists every competing system we know of, and says plainly when another model suits better, including our head-to-head comparisons such as vs. AcuityPro and vs. PVVAT.

Common questions

What is visual acuity software?
Visual acuity software displays calibrated eye charts — Snellen, ETDRS/LogMAR, pediatric optotypes and related clinical tests — on a computer monitor, tablet or wall display instead of a chart projector or printed chart. Optotype sizes are calculated from the patient-to-screen distance the clinician enters, and letters can be randomized between presentations so patients cannot memorize the chart.

Is visual acuity software the same as an eye chart app?
The terms overlap. Computerized eye chart, electronic eye chart, digital eye chart, Snellen chart software and eye chart software all describe the same category. The clinical distinction that matters is calibration: a consumer eye chart app that does not calibrate optotype size to a verified testing distance is not suitable for clinical measurement.

What should a practice look for when choosing visual acuity software?
The main decision points are the chart set (Snellen, ETDRS/LogMAR, pediatric optotypes, binocular and refraction-support tests), distance calibration, the delivery model (browser-based, installed desktop software, or an integrated hardware system), the platforms it runs on, whether pricing is published, and whether a full-featured trial is offered.