Long-term changes in retinal layers in patients undergoing intravitreal ranibizumab for neovascular age-related macular degeneration

Abstract

Purpose: To analyze long-term changes in individual retinal layers (RLs) after intravitreal injections of ranibizumab (IVRs) in patients with neovascular age-related macular degeneration (n-AMD). Methods: The patients were treated with 0.5-mg IVRs based on an as-needed protocol after the first three monthly doses over a 12-month follow-up period. Patients underwent optical coherence tomography and best-corrected visual acuity (BCVA) evaluation at each visit. The ETDRS grid with central subfield (R1) (r 0.5 mm) and the inner ring (R2) (r 0.5–1.5 mm) was used for calculation of the mean thickness of each RL. Changes in the thickness of segmented RLs within the R1 and R2 of ETDRS circles at months-3, -6, and -12 were compared to baseline. Results: The mean age was 72 ± 7.4 years. The mean number of injections was 9.08 (range 6–11). Mean BCVA improved from 49.7 ± 22.1 to 60.1 ± 19.8 letters. Central macular thickness decreased from 390.25 ± 149.6 to 312.74 ± 118.4 μm. Thicknesses of GCL (from 23.93 ± 13.73 to 19.50 ± 9.50 μm in R1; p 0.001, and from 44.5 ± 12.6 to 39.6 ± 10.6 μm in R2; p 0.005), IPL (from 28.90 ± 14.36 to 22.35 ± 6.23 μm in R1; p 0.001, and from 39.34 ± 8.53 to 35.58 ± 7.93 μm in R2; p 0.004), and total inner RL (ILM to ELM) (from 222.93 ± 93.09 to 180 ± 53 μm in R1; p 0.001, and from 255.06 ± 42.74 to 240.25 ± 40.37 μm in R2; p 0.003) in the central and parafoveal rings decreased statistically at month-12. Decrease in INL was limited to month-6 (from 34.80 ± 15.33 to 27.60 ± 12.59 μm in R1; p 0.001), while decreases in total outer RLs (ELM to RPE) (from 128.32 ± 26.92 to 115.54 ± 43.98 μm in R1; p 0.001, and 103.81 ± 16.73 to 96.38 ± 16.22 μm in R2; p 0.014) and RPE (from 39.12 ± 22.33 to 29.70 ± 22.05 μm in R1; p 0.001, and from 31.27 ± 13.11 to 24.40 ± 9.99 μm in R2; p 0.001) were limited to month-3. Conclusions: Significant changes were observed in the thickness of the inner RLs after 1-year treatment with IVRs for n-AMD. A significant decrease in RPE thickness confined to the first months disappeared at month-12.