Abstract
Purpose: :
To examine the relationship of abnormal optical coherence tomography (OCT) measurements of the retinal nerve fiber layer (RNFL) in exudative and non-exudative age-related macular degeneration (AMD).
Methods: :
We performed a retrospective medical record review of our own clinic population to identify patients with either exudative or non-exudative AMD in both eyes who also had Cirrus HD-OCT scans of the macula and RNFL on the same day. Subjects were excluded if they had been identified as a glaucoma suspect, had ocular hypertension, or had a prior diagnosis of glaucoma. Central foveal thickness (CFT), as well as the presence or absence of global RNFL thickening, temporal sector thickening, or any clock hour thickening (defined as greater than 95% of the value for the normative population) were recorded. The presence or absence of geographic atrophy (GA) based on clinical exam and imaging was also recorded.
Results: :
We identified 66 eyes of 33 patients with a mean age of 79.3 years (SD 7.49). 30.3% were female. Exudative AMD was present in 66.7% of eyes, and GA was present in 21.2% of eyes. The mean CFT was 313 microns (SD 109). Two eyes were excluded from the RNFL analysis due to RNFL scan segmentation failures. Global RNFL thickening was present in 4.54% of eyes with non-exudative AMD and in 22.5% of eyes with exudative AMD. Temporal sectoral thickening was present in 18.1% of eyes with non-exudative AMD and in 27.5% of eyes with exudative AMD. At least one clock hour with thickening was present in 36.4% of eyes with non-exudative AMD and in 52.5% of eyes with exudative AMD. A generalized estimating equation logistic regression model was used to determine 95% confidence intervals. Male gender was negatively related to global RNFL thickening (OR 0.0988, p = 0.0007 [95% CI: 0.0184 - 0.531]) and presence of exudative AMD was positively related to global RNFL thickening (OR: 3.9065, p = 0.014 [95% CI: 1.3209 - 11.553]). Central foveal thickness was weakly related to the presence of temporal RNFL thickening (OR: 1.009, p = 0.014 [95% CI: 1.0018 - 1.02]). Male gender was negatively related to the presence of at least one clock hour of RNFL thickening (OR: 0.148, p = 0.034, [95% CI: 0.0256 - 0.788]).
Conclusions: :
Female gender and the presence of exudative AMD were strongly associated with global thickening of the circumpapillary RNFL. CFT appears to have a much smaller effect on RNFL thickening. Exudative AMD-associated RNFL thickening may be due retinal edema extending to the circumpapillary region, but the precise relationship has yet to be determined.
Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer