Aim: To compare the retinal morphological characteristics of eyes with choroidal neovascularisation (CNV) secondary to pathological myopia versus eyes with CNV secondary to age-related macular degeneration (AMD), using quantitative optical coherence tomography (OCT) subanalysis.
Methods: Twenty-one eyes of 21 patients newly diagnosed as having CNV secondary to pathological myopia, and 43 consecutive cases of eyes with newly diagnosed subfoveal CNV secondary to AMD were retrospectively collected. In all patients, StratusOCT images and fluorescein angiograms (FA) were available for analysis. StratusOCT images were analysed using custom software (termed “OCTOR”), which allowed calculation of the thickness/volume of the neurosensory retina, subretinal fluid (SRF), subretinal tissue (SRT) and pigment epithelial detachments (PEDs). FA images were used to calculate CNV leakage area and CNV lesion size for each eye.
Results: The total volume of neurosensory retina in the pathological myopia group was significantly less than in the AMD group (7.10 (SD 0.50) mm3 vs 7.76 (0.93) mm3, p = 0.004). The total volume of SRF in the pathological myopia group was less than in the AMD group, but the difference was not statistically significant (0.33 (1.38) mm3 vs 0.55 (0.82) mm3, p = 0.434). The total volume of SRT in the pathological myopia group was less than in the AMD group, but the difference was not statistically significant (0.16 (0.15) mm3 vs 0.36 (0.60) mm3, p = 0.144). The total volume of PED in the pathological myopia group was markedly less than in the AMD group (0.01 (0.03) mm3 vs 1.09 (1.89) mm3, p<0.001). On FA, the total leakage of CNV in the AMD group was significantly greater than in the pathological myopia group (4.17 (3.29) DAs vs 0.53 (0.58) DAs, p<0.001).
Conclusions: CNV lesions in pathological myopia were associated with considerably less retinal oedema, SRF and SRT compared with CNV associated with AMD. PEDs were almost negligible in myopic lesions compared with AMD. These findings are consistent with previous clinical and angiographic descriptions of myopic CNV as relatively small lesions with modest exudation.
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Funding: Supported in part by NIH Grant EY03040 and NEI Grant R01 EY014375.
Competing interests: ACW and SRS are co-inventors of Doheny intellectual property related to spectral domain optical coherence tomography that has been licensed by Topcon Medical Systems. However, it is not related to the article’s subject matter.
Ethics approval: Ethics approval was obtained.