Potential Acuity Estimation
Potential acuity estimation can be helpful in assessing lenticular contribution to vision loss. The potential acuity pinhole test is a simple but accurate method of evaluation for patients who do not have other ocular pathology and whose visual acuity is better than 20/200. For this test, the patient is asked to read a brightly illuminated near card through a pinhole aperture. The Retinal Acuity Meter, or RAM (AMA Optics), functions in a similar manner.
The Potential Acuity Meter, or PAM (Mentor Graphics/Marco), is one of several instruments that project a numerical or Snellen vision chart through a small entrance pupil. The image can be projected onto the retina, around lenticular opacities, allowing for an estimate of what the BCVA would be if the media abnormality were absent.
It is important to note that these tests can be misleading in patients with certain disorders, including age-related macular degeneration, amblyopia, macular edema, glaucoma, small macular scars, and serous retinal detachment. An accurate clinical examination of the eye is often the best predictor of visual outcome.
Melki SA, Safar A, Martin J, Ivanova A, Adi M. Potential acuity pinhole: a simple method to measure potential visual acuity in patients with cataracts, comparison to potential acuity meter. Ophthalmology. 1999;106(7):1262–1267.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.