Plus +1.00 Blur Test

The verification of refraction (post) with +1.00 D is performed towards the end of a subjective refraction to determine if a young patient with accommodative ability has been over-minused or under-plussed, meaning they have accommodated during the course of their refraction. The blur test is usually conducted after the best subjective evaluation of the sphere of vision.

Procedure:

1. Occlude one eye.

2. Place a +1.00 DS trial lens over the best sphere of vision of the test eye.

3. If the original visual acuity is 6/6 (the average for a young patient), it should be reduced by four lines to approximately 6/18 with the blur lens.

4. If the visual acuity is better than 6/18 with the blurry lens, it suggests that the patient has been under-minused, meaning accommodating.

5. Adjust your refraction until or unless VA on 6/18