Can objective parameters in optical coherence tomography be useful markers in the treatment and follow-up of type 1 and type 2 macular neovascularizations related to neovascular age-related macular degeneration?

PURPOSE: The aim of this study was to compare the responses of type 1 and type 2 macular neovascularizations (MNV) caused by neovascular type age-related macular degeneration (n-AMD) to intravitreal anti-vascular endothelial growth factor (VEGF) treatments using quantitative parameters determined by optical coherence tomography (OCT). Additionally, it was also intended to assess the connections between these quantitative parameters and changes in best-corrected visual acuity (BCVA) and the number of intravitreal anti-VEGF injections required within a year.

MATERIALS AND METHODS: In our retrospective and observational study, the data of 90 eyes of 90 patients diagnosed with n-AMD and treated with intravitreal anti-VEGF with the "Pro re nata" method were evaluated. Subtypes of existing MNVs were distinguished with previously taken optical coherence tomography angiography (OCTA) images. In spectral domain OCT examinations, central macular thickness (CMT) and central macular volume (CMV) values were recorded at baseline and 12th month. The number of intravitreal anti-VEGF injections during the 12 month follow-up period was also recorded for each patient. Obtained data were compared between MNV types.

RESULTS: Of the n-AMD cases examined in the study, 56.66% had type 1 MNV and 43.34% had type 2 MNV. The mean baseline BCVA logMAR values in eyes with type 2 MNV (1.15 ± 0.43) were higher than those observed in eyes with type 1 MNV (0.76 ± 0.42) (p = 0.001). Similarly, mean baseline CMT and CMV values in eyes with type 2 MNV were higher than those observed in eyes with type 1 MNV (respectively 424.89 ± 49.46 μm vs. 341.39 ± 37.06 μm; 9.17 ± 0.89 μm3 vs. 8.49 ± 0.53 μm3 ; p < 0.05). After 12 months of treatment, logMAR values of BCVA (0.86 ± 0.42) in subjects with type 2 MNV were higher than those in subjects with type 1 MNV (0.57 ± 0.37) (p = 0.001). Mean CMT and CMV values at 12th month in subjects with type 2 MNV (379.11 ± 46.36 μm and 8.66 ± 0.79 μm3 , respectively) were observed to be higher than those with type 1 MNV (296.95 ± 33.96 μm and 8.01 ± 0.52 mm3 , respectively) (p < 0.05). In type 2 MNVs, positive correlations were observed between both baseline and 12th month BCVA logMAR values and baseline CMV (p < 0.05). Similarly, in type 2 MNVs, a positive correlation was observed between 12th month BCVA logMAR values and 12th month CMV (p < 0.05). The total number of intravitreal anti-VEGF injections at 12 months was similar in both groups (p = 0.851).

CONCLUSION: In this study, in which we performed a subtype analysis of MNV cases, we observed that the visual function was worse at the beginning and the end of the 12th month, and the CMT and CMV values were higher in the type 2 MNV group compared to the type 1 MNV cases. In addition, we found significant correlations between BCVA logMAR values and CMV values in type 2 MNV cases. In the follow-up of these cases, CMT, which is a more widely used quantitative method, and CMV, which is a newer OCT measurement parameter, may be more useful in patient follow-up and evaluation of treatment efficacy, especially for type 2 MNV cases.