Legally Blind

“Pt is legally blind”

What does it mean when a patient is legally blind? Technically, to be legally blind, one’s visual acuity in the best correction is less than 20/200. Here is a great simulator to help one imagine what that would look like. But functionally, how does being “legally blind” affect the patient?

We need more information

A patient can be legally blind for several reasons. Diseases such as cataracts, macular degeneration, and diabetic retinopathy all leave a patient with reduced visual acuity but leave the patient with very different residual vision and different functional problems as a result of the specific condition.

A patient with macular degeneration will have reduced vision in the central field affecting reading and the ability to see faces like the below picture.


Glaucoma will result in reduced peripheral vision that could affect balance and peripheral awareness.


With retinopathy, the areas of reduced vision may be more random and will have different effects depending on just where these damaged areas are.


How bad is it?

Is the patient’s vision truly 20/200 or is it worse? Visual acuities can be 20/400 or even 20/1000. A patient may have an acuity described as “NLP” or no light perception. In this case, the patient would see nothing but blackness.

A patient that was 20/400 and now is improved to 20/200, will find their vision to be much improved and very happy about that.

Is the described acuity with glasses in place? Specialized low vision refraction from a low vision optometrist could get the patient improved visual acuity optimizing their residual vision.

Ask the Right Questions

Why does this patient have a low vision? How bad is their acuity? Are they wearing the best possible glasses for their diagnosis? With this information, we will be better able to assess the functional implications of these patients reduced vision and come up with the most effective strategies to keep them independent and safe.