Pinhole test is an effective tool to determine if distance visual acuity can be corrected with glasses or contact lenses.
The pinhole disk admits only central rays of light, that do not need to be refracted by the cornea or lens to fall to a point on the retina as opposed to a circle of blur. A single pinhole of not more than 2.4mm or a multiple circular arrangement of 1.0mm pinholes can be used.
Upon reevaluation with the pinhole, if a patient’s visual acuity improves two or more lines, there is probably a refractive error present, and refraction (evaluation for corrective lenses) should be performed before any further testing.
If the acuity is not improved with pinhole evaluation, it is likely that the cause of the decreased visual acuity is not refractive, and further ophthalmologic evaluation is indicated.
Performance of the Pinhole Acuity should include the following steps:
- Position the patient with corrective lenses.
- Occlude the eye not being evaluated and position the pinhole(s) in front of the eye being evaluated.
- Instruct the patient to look through the pinhole(s) at the distance chart.
- Instruct the patient to use small movements of the paddle to align the pinhole(s) so they can read the optotypes from right to left.
- Have the patient begin reading on the last line that was seen without the pinhole(s)
- The smallest line read from the distance Snellen chart is recorded in the patient’s medical record following the already recorded distance acuity.
- Repeat above procedure for the fellow eye.
Optometry Notebook 