Author: Mahima Jhingan
Co-authors: Wiiliam Freeman, Jay Chhablani
Abstract
Purpose: To study the impact of long term use of intravitreal anti vascular endothelial growth factors (anti-VEGF) on the choroid in poor responders versus good responders in neovascular AMD(nAMD).Methods: A retrospective review of patients undergoing treatment for nAMD at a tertiary institute were reviewed at presentation. Poor responders(PR) were eyes on long-term anti-VEGF(vascular endothelial growth factor) treatment with inability to extend beyond a month without a relapse and needed double the dose of medication(n=20). Good responders(GR) were eyes that went into long-term remission after at least three injections and remained dry for more than a year until the last visit(n=20). Patients underwent comprehensive ophthalmological evaluation, fluorescein angiography(FA) and optical coherence tomography(OCT) at presentation and last visit. Choroidal vascularity index(CVI), subfoveal choroidal thickness(SFCT), choriocapillaris thickness(CC) and Haller’s and Sattler’s layer thickness(HSL) were analyzed for statistical significance, besides demographic factors.
Results: Mean age at presentation was 76.9 (± 7.2) years in the poor responders, which was similar to mean presenting age in good responders at 79.07 (± 6.15). Slight female preponderance was noted in the poor (61.1%) and good responders (72.2%). Mean follow-up was 72.5 (± 26.1) months in poor responders, and it was statistically insignificant in its difference at 84.5 (± 28.1) months in good responders(p=0.17). The mean number of injections (poor-50.35 months versus good-18.9 months) and average treatment free interval (poor-6.75 months versus good-49.25 months) differed significantly in the two groups(p<0.0001). Both groups demonstrated a statistically significant reduction in CRT, CC, HSL, SFCT, CVI and increase in size of geographic atrophy(GA) from baseline to last visit. The two groups at the final visit differed significantly in their SFCT[PR =185.3 (80.11); GR =139.95 (57.46), p=0.037], HSL[PR =167.40 (77.92); GR =139.95 (57.46), p=0.046], CVI [PR =63.77 (3.06); GR=61.70 (3.21), p=0.04], size of GA in mm2[PR =1.28 (2.49); GR =5.2 (6.6),p=0.01]and rate of growth of GA in mm2 per year[PR =0.133 (± 0.2); GR =0.579 (± 0.7),p=0.009]. BCVA did not show a statistically significant difference between the two, and from baseline to last visit.
Conclusion: Long term follow shows us statistically significant thinning of the choroid with its components, along with a corresponding reduction in CVI in both good and poor responders. The rate of growth of GA is higher in GR compared with PR. Vision is well maintained despite prolonged high dose therapy.
