Predictors of visual outcome in eyes with choroidal neovascularization secondary to age related macular degeneration treated with intravitreal bevacizumab monotherapy

Abstract

Aim: To evaluate the predictors of visual improvement in eyes with naive choroidal neovascularization secondary to age-related macular degeneration (CNV -AMD) treated with intravitreal bevacizumab (IVB) monotherapy.

Methods: Fifty eyes with naive CNV- AMD with pretreatment best-corrected visual acuity (BCVA) better than 20/200 and treated with IVB monotherapy were evaluated. Several variables including age, sex, pre-treatment BCVA, CNV type and lesion size on fluorescein angiogram as well as SD-OCT parameters including pre-treatment central macular thickness (CMT), inner-segment/outer-segment (IS/OS) junction integrity, and external limiting membrane (ELM) integrity were analyzed to predict visual outcome.

Results: On univariate regression, pretreatment ELM damage was associated with less visual improvement after treatment (P=0.0145). However, ELM damage predicted only 10% of the visual outcome. On multivariate regression, pretreatment BCVA, IS/OS junction, and ELM integrity on SD-OCT were the significant predictors for the treatment effect and together predicted 37% of visual improvement.

Conclusion: Pretreatment BCVA, ELM and IS/OS junction integrity on SD-OCT are of significant value in predicting the visual improvement in naive wet AMD patients treated with IVB monotherapy.

Keywords: age-related macular degeneration; avastin; choroidal neovascularization; external limiting membrane.

Figure 1. Assessment of external limiting membrane (ELM) (arrow) and inner segment / outer segment (IS/OS) junction integrity in eyes with choroidal neovascularization prior to treatment using spectral-domain optical coherence tomography (SD-OCT)

A: ELM (arrow) and IS/OS (arrow-head) are preserved in the central 1 000 microns over a fibrovascular pigment epithelium detachment (PED) with subretinal fluid (SRF); B: Preserved ELM (arrow) but completely disrupted IS/OS (arrow-head) in the central 1 000 microns with small PED and thickened retinal pigment epithelium (RPE) complex; C: Disruption of both ELM (arrow) and IS/OS junction (arrow-head) in the central 1 000 microns with thickened retina and intraretinal fluid with fibrovascular PED; D: Minimal disruption (10%) (Thick arrows) of ELM (arrow) with complete disruption of IS/OS junction (arrow-head) in the central 1 000 microns with subretinal fluid and bumpy retinal pigment epithelium.

Figure 2. A and B: Case 1: Intact ELM and IS/OS at baseline. Eighty-one year old female with pretreatment BCVA of 44 ETDRS letters (20/63⁻¹) presented with intact ELM (arrow) and IS/OS (arrow-head) junction in the central 1000 microns as seen on spectral-domain optical coherence tomography (SD-OCT) (A) BCVA improved to 67 letters (20/25⁺²) following four monthly intravitreal Bevacizumab injections (B): C and D: Case 2: Completely disrupted ELM and IS/OS at baseline. Eighty-year old female with pretreatment BCVA of 29 ETDRS letters (20/125⁻¹) presented with completely disrupted ELM (arrow) and IS/OS (arrow-head) junction in the central 1000 microns seen on spectral-domain optical coherence tomography (SD-OCT) (C) BCVA improved to 35 letters (20/100) following seven monthly intravitreal Bevacizumab injections (D).

Figure 3. Graph showing association of ELM damage (in percentage) with change in BCVA (in ETDRS letters) after treatment (ELM = External limiting membrane, BCVA=Best corrected visual acuity).

Figure 4. Graphs showing statistical analysis of predictive factors for visual outcome in multivariate regression analysis (Red dotted lines are 95% confidence interval of the regression line, blue dotted line is the line of mean of all data points).