Anatomic Relationships Between Disc Hemorrhage and Parapapillary Atrophy

Abstract

Purpose: : Parapapillary atrophy (PPA) and disc hemorrhage (DH) are associated with glaucoma. The current project seeks to determine if an anatomic relationship exists between them.

Methods: : We reviewed all digital stereodisc photographs obtained on 1559 glaucoma patients obtained between 10/1/2006 and 9/30/2007 and evaluated them for the presence, extent, and location of DH and PPA. The location of the maximal PPA width as defined by the radial distance between the scleral rim and the outer border of the beta zone was determined in each eye with DH. The clock hour location of the DH and the point of maximum PPA were recorded. For each patient with DH, baseline central corneal thickness (CCT), intraocular pressure (IOP) on the day that the DH was detected were obtained for both eyes by chart review. Vertical cup to disc ratio (VCDR) was determined for each eye by an expert examiner who was masked to the study protocol.

Results: : We identified and analyzed 46 eyes with photographically documented DH. Asymmetric PPA was identified in 38 eyes (82.6%). Disc hemorrhages occurred more frequently in the eye with the greater PPA (29/38 eyes (76.3%); kappa=0.611, p<0.001). The average distance between the DH and maximal PPA was 1.7 ± 1.6 (range, 0 to 6) clock hours. The DH fell on the point of greatest extent of PPA from the disc margin in 10/42 eyes (23.87%; p < 0.05, FET) and within 2 clock hours of the greatest PPA in 31/42 eyes (73.8%; p < 0.001, chi square). Using univariate logistic regression analysis, PPA but not IOP, CCT, or VCDR significantly predicted the laterality of the disc hemorrhage (odds ratio [OR] = 17.50; 95% CI 3.31, 92.48; p = 0.001).

Conclusions: : Disc hemorrhages tend to occur in the eye with the greatest PPA and are usually found within the region of the greatest extent of the PPA. Further research is necessary to determine whether the PPA predisposes to disc hemorrhage or vice versa or whether an underlying mechanism predisposes to both.

Keywords: anatomy • optic nerve • retinal pigment epithelium