Physical absence of one eye.
The central piece of evidence for this condition is a formal visual acuity measurement of your remaining eye. Medical records showing a Snellen chart test result — the fraction such as 20/40 or 20/200 — directly map to the rating criteria, so any eye examination that documents corrected or best-corrected distance visual acuity in the remaining eye is critical.
Records from an ophthalmologist or optometrist are the most direct source. A VA Compensation and Pension examination will also test and record visual acuity. If your remaining eye has a condition that affects your vision, treatment records for that condition help show the current level of acuity.
Statements from you or people who know you can describe how reduced vision in your remaining eye affects daily activities such as reading, driving, or working, which supports the overall picture of how the loss of one eye affects your life.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.
