Blindness in One Eye — How Many Disability Percentage Points

Blindness in one eye is among the most common conditions at ophthalmic medical boards: after trauma, severe infection, retinal disease, or surgery that did not go well. It is also one of the conditions where the gap between the experience and the number in the schedule comes as a surprise: a person who has lost an eye sees the loss of half their vision, while the impairment schedule sees 30%. Here is how it works, and why small differences matter so much precisely here.

The data on this page comes from the same impairment schedules on which the eye disability percentage calculator is built — the same clauses, the same figures.

What the table says

The foundation is the visual acuity table: a grid intersecting the best corrected acuity of the two eyes. When the fellow eye is healthy (6/6), the relevant row provides:

• acuity of 6/60 in the damaged eye — 20%
• acuity of 3/60 — 25%
• acuity of 1/60 and below, down to no light perception at all — 30%

From the table’s point of view, then, an eye that sees 1/60 and an eye that perceives no light at all are assessed identically: 30%. The table does not distinguish between degrees of practical blindness — below 1/60, everything counts as the end of that eye’s scale.

The addition for enucleation

Where the eye is not merely blind but was removed (enucleation) or has atrophied (phthisis), the schedule adds 5% arithmetically, on top of the table percentage. A removed eye with a healthy fellow eye thus reaches 35%. This is one of the few explicit exceptions that survive even above the single-eye ceiling, so it matters that the enucleation is documented in the file.

The exception that changes entitlement: the exclusion rule

In general disability there is an “exclusion”: impairments of acuity and visual field whose combination does not exceed 25% are not counted towards entitlement to a benefit. But the rule carries an explicit exception — except where the visual acuity of one eye is 3/60 or below.

Blindness in one eye sits squarely inside that exception. The practical meaning: 25% for an eye at 3/60 sounds “modest,” but thanks to the exception it counts in full in the overall weighting — whereas a mild bilateral reduction earning the same percentage would be excluded. For someone who has lost vision in one eye, this is one of the most important lines in the schedule.

When the fellow eye is not perfect

The table is two-dimensional, so any reduction in the better eye climbs quickly. An eye with no light perception at all, against a fellow eye with acuity of:

• 6/9 — 30%
• 6/12 — 40%
• 6/21–6/24 — 55%
• 6/30–6/36 — 70%
• 6/60 — 90%
• 3/60 — 95%
• total blindness in both eyes — 100%

(For an eye seeing 1/60, the figures in the middle columns run slightly lower — 35% against 6/12, for instance; the exact intersection appears in the full table.)

This is also the medical basis for every ophthalmologist’s first concern in a one-eyed situation: protecting the seeing eye. Any change in it — a developing cataract, retinal disease, glaucoma — alters not only function but the assessment, which makes regular follow-up and consistent documentation of the better eye doubly important.

What does not accumulate

Total disability for defects of one eye is capped at the percentage that would be set were that eye completely blind — the single-eye ceiling. An eye already assessed as blind therefore receives no additional percentage points for the visual field lost on that side or for its other defects; the explicit exceptions, chiefly the addition for enucleation, sit outside this rule.

One further principle worth knowing: where there are impairments in the fellow eye or in other systems, the percentages are weighted — each further impairment is taken from the remainder, so 30% plus 10% gives 37%, not 40%.

The driving licence — a separate system

A question that comes up in almost every conversation: “And what about my licence?” It is important to keep the two apart: fitness to drive is determined by the Medical Institute for Road Safety under its own rules, and it is not derived from disability percentages nor decided by a National Insurance board. These are two separate tracks with different criteria.

Before the board

The decisive documentation in a one-eyed situation is simple but twofold: best corrected acuity for both eyes, current and stable — because the percentage derives from the intersection, and it is the better eye that determines the row. Where an enucleation was performed, the surgical records, for the addition. And for anyone preparing for a complex board or considering an appeal, the page on the expert medical opinion in ophthalmology explains the role of a specialist opinion in the process.

A particular and frequent case: when the damaged eye lost vision because of corneal disease — a scar, advanced keratoconus, or graft failure — the question is sometimes not only assessment but the possibility of rehabilitation. In suitable cases a corneal transplant can restore sight to an eye considered lost, and with it the whole picture changes.

The assessment on this page is general only and is not a medical opinion or legal advice.