Purpose:
To compare the retinal morphologic characteristics using optical coherence tomography (OCT) of eyes with choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) and eyes with pathologic myopia using quantitative and qualitative subanalysis.
Methods:
Fifteen eyes with CNV secondary to pathologic myopia and fifteen eyes with CNV secondary to AMD were randomly, retrospectively selected between 2008-2009. Inclusion criteria for the pathologic myopia group were subfoveal CNV and a refractive error >-6.00 diopters. All patients in the AMD group were >60 years of age, had drusen and subfoveal CNV. In both groups there was no other apparent cause of CNV. All eyes had newly diagnosed CNV and had not previously received treatment. In all patients, Zeiss CirrusTM HD-OCT images were available for analysis, allowing for calculation of the thickness and volume of the neurosensory retina, and thickness of subretinal fluid (SRF), subretinal tissue (SRT), and pigment epithelial detachments (PEDs) at the foveal center point (FCP).
Results:
The total macular cube volume of the neurosensory retina in the AMD group was significantly greater than in the pathologic myopia group (10.36±2.23 mm3 vs. 8.29±2.17 mm3, p=0.016). The thickness of the neurosensory retina at the FCP was significantly higher in the AMD group than the pathologic myopia group (377.6±140.73 µm vs. 251.07±92.56 µm, p=0.008). The thickness of the SRF at the FCP in the AMD group was greater than in the pathologic myopia group, but the difference was not significant (12.46±35.11 µm vs. 0.27±0.70 µm, p=0.199). The thickness of SRT at the FCP in the AMD group was greater than the pathologic myopia group, but this difference was also not significant (102.85±73.0 µm vs. 86.73±60.24 µm, p=0.560). The height from the choroid to internal limiting membrane was also not significantly different (729.6±372.32 µm vs. 582.93±110.74 µm, p=0.160). There was a significantly higher frequency of PEDs in AMD compared with pathologic myopia (Χ2=10.159, p=0.001), with an average volume of 1.39±1.19 mm3 in the AMD group. The volume of PEDs was too small to quantify in the pathologic myopia group.
Conclusions:
Newly diagnosed CNV lesions in AMD were associated with a greater thickness and volume of the neurosensory retina, and thickness of SRF and SRT than in pathologic myopia. The presence and volume of PEDs in pathologic myopia were negligible compared to AMD. This study is consistent with prior angiographic descriptions of CNV in pathologic myopia, as well as prior Zeiss StratusTM OCT comparisons.
Keywords: choroid: neovascularization • myopia • age-related macular degeneration