• Written By: Alan S. Crandall, MD

    This prospective study published in December in the Journal of Glaucoma compares the standard swinging flashlight method of testing for a relative afferent pupillary defect (RAPD) with two novel techniques: the magnifier-assisted swinging flashlight method and the ophthalmoscopic swinging flashlight method. The authors found the magnifier-assisted method to be the most sensitive. These results confirm their earlier study suggesting that this method can provide a simple, inexpensive, reproducible way of detecting an RAPD.

    The two new assessment techniques using a magnified view of the pupil are easy to perform, reproducible and something all ophthalmologists will find useful. This article also provides a good review for general ophthalmologists on RAPD in glaucoma patients. These patients sometimes have small pupils from chronic miotic medication usage, or irregular pupils from pressure-related iris ischemia or prior glaucoma surgery.

    The ophthalmoscopic swinging flashlight is identical to the standard swinging flashlight method except that the observer looks at the pupil through a direct ophthalmoscope and uses the light beam of the ophthalmoscope as the light source.

    This study enrolled 101 consecutive patients (68 diagnosed glaucoma patients, 20 glaucoma suspects including ocular hypertensives, and 13 controls). Pupils were screened by three masked examiners for the presence or absence of an RAPD using the three methods.

    The magnifier-assisted method was performed in the same way as the standard method except that a high plus +20 D magnifying lens was held in front of the eye being observed, as close to the eye as possible without touching it. Light was then shined into each eye in the same manner as in the standard method: three seconds in each eye and repeated until the nature of the pupillary response in each eye was clear. The plus lens was then moved to the other eye and the procedure repeated.

    Weighted κ scores revealed substantial agreement between tests for the same method and moderate to substantial agreement among the observers. However, the authors found a significant improvement in test sensitivity with the magnified-assisted method for both advanced and more subtle RAPD disease.