Abstract
Purpose: :
To assess the asymmetry in the average retinal nerve fiber layer (RNFL) and visual field indices in glaucoma patients that demonstrate a relative afferent pupillary defect (RAPD).
Methods: :
The author reviewed the last consecutive 50 patients seen with a diagnosis of primary open angle or low tension glaucoma at a tertiary referral center. Patients who had their pupils examined by the author prior to dilation and who had a reliable Humphrey visual field test and Optical Coherent Tomography analysis of the RNFL in both eyes were included. The author did not have any clinical information prior to his exam of the pupils. The presence or absence of a RAPD was recorded.
Results: :
Of 50 patients reviewed, 35 patients met the inclusion criteria. The mean RNFL of all eyes of the included patients was 73.2 ± 7.2 microns with no significant differences between the right and left eyes (p = 0.88). The Humphrey visual field of all eyes in the included patients had a mean Mean Deviation of –5.9 ± 7.2 decibels and a mean Pattern Standard Deviation of 3.8 ± 2.9 decibels with no significant differences between the right and left eyes (p = 0.37, p = 0.45). A RAPD was found in 51% (18 of 35) of the patients including 8 right eyes and 10 left eyes. The mean RNFL difference between eyes in patients without a RAPD was 7.2 ± 5.3 microns (range 1 to 16 microns). The mean RNFL difference between eyes in patients with a RAPD was 14.4 ± 13.6 microns (range –2 to 38 microns). Patients with a RAPD had more asymmetry in their RNFL than those without a RAPD (p = 0.024). Four of the eyes with a RAPD had a greater RNFL than the contralateral eye with a mean difference of – 1.8 microns. In the group of patients with a RAPD, the average Mean Deviation in the eye with the RAPD was –9.2 ± 7.9 decibels and in the contralateral eye, –4.0 ± 4.2 decibels (p = .00012). The average Pattern Standard Deviation in the eye with the RAPD was 5.5 ± 3.7 decibels and in the contralateral eye, 3.2 ± 2.7 decibels (p = .0026). The average RNFL in the eye with the RAPD was 64.0 ± 13.3 microns and in the contralateral eye, 78.5 ± 16.4 microns (p = .00016).
Conclusions: :
A RAPD can be found in glaucoma patients with more severe and asymmetric RNFL and visual field loss in the eye demonstrating the RAPD.
Keywords: pupillary reflex • nerve fiber layer • imaging/image analysis: clinical