Purpose:
Pigment epithalium detachment (PED) is a common finding in age-related macular degeneration (AMD); RPE tears are a rare but well-documented sequela, which occur either spontaneously or following treatment. The aim of this study is to identify tomographic features which could be predictive of PED rip predisposition.
Methods:
92 patients were examined retrospectively; every patient presented with a diagnosis of serous or vascular PED secondary to AMD. Of these patients, 42 (45.6%) had been treated with intravitreal bevacizumab (Avastin®), and received a mean of 1.38 ± 0.65 injections (range, one to three). The remaining 50 subjects (54.3%) had been followed closely without any treatment. The mean follow-up was 12.3 ± 10.3 weeks (range, 4 to 28 weeks). We examined the OCT scan at baseline (diagnosis), measuring the PED height, the base diameter of the PED, the position of the CNV relative to the PED, volume index (defined as PED height multiplied by PED surface area in mm3), and amount of subretinal fluid (defined as none, mild, moderate, and marked).
Results:
Of the whole 92 patients, 12 (13%) developed a rip of the PED (Group 1), 8 (19 %) in the treatment arm and 4 (8%) in the control arm, with subsequent massive drop in visual acuity. Significantly greater mean PED height was found in Group 1 in comparison to non-complicated eyes (Group 2) (624.9 ± 216.0 µm vs. 312.1 ± 201.9 µm; P = 0.001, t test), while the base diameter was >5000 µm in Group 1. There was higher mean volume index for Group 1 eyes compared with Group 2 eyes (8.9 ± 5.7 vs. 3.1 ± 4.0 mm3; P = 0.001, t test); as far as the position of the CNV in respect to the PED is concerned, in the non-complicated group 87% of the CNV (either type 1,type 2 or type 3) were located at least 70 µm inside the PED, whereas in the RPE tear group, 94% were located at the margin of the PED and the remaining 6% were located inside the PED within 50 µm to the margin. Chi-square analysis showed significantly more SRF in Group 1 in comparison to Group 2 eyes (P = 0.002).
Conclusions:
Univariate analyses in this study showed increased PED height, PED base diameter and greater amount of SRF in PED eyes that developed RPE tears (Group 1) in comparison to PED eyes without RPE tears (Group 2). Increased volume index associated with a tendency for RPE tears is an interesting finding too.The presence of a CNV at the margin of the PED is associated with an increased risk of postinjection tear due to the enhanced mechanical contraction of the membrane.In conclusion, SD-OCT measurement of a PED might help in decision-making.
Keywords: age-related macular degeneration • retinal pigment epithelium • imaging/image analysis: clinical