Treatment Effects of Ranibizumab (LucentisTM) in Patients With Pigment Epithelial Detachments Due to Neovascular Age Related Macular Degeneration Using High Definition Optical Coherence Tomography

Abstract

Purpose:: Ranibizumab has proven clinical efficacy in patients with neovascular age related macular degeneration (nAMD). However, its effect on pigment epithelial detachments (PED) has not been evaluated in detail. This study analyzes the effects of Ranibizumab on PED using high definition raster scanning optical coherence tomography (HD-OCT) in combination with semi-automatic segmentation software. Time course and changes in retinal microstructure, i.e retinal volume (RV) subretinal fluid (SRF), intraretinal cysts (IRC), affected area (AA) and subpigmentepithelial volume (PEDV), were evaluated.

Methods:: 15 eyes of 15 patients with PED due to nAMD were imaged using a frequency domain HD-OCT system (Prototype of Cirrus^TM HD-OCT) with an axial resolution of 6 µm and 20 k A-scans/second resulting in a 5.8x5.8x2 mm³ retinal volume block. Two-dimensional quasi-histologic section analysis and three-dimensional topographic reconstructions were performed using 3D-Doctor^TM, Able Software Corp. Ranibizumab was administered at baseline, month 1 and 2. Follow up time was 3 months.

Results:: Specific information about distribution of fluid accumulation and volumetric measurements can be obtained in all compartments. Errors in segmentation are avoided due to the controlled, semi-automatic mode. Changes in reflectivity are demarcated within the outer nuclear/plexiform layers in close relation to subretinal fluid or PEDs. Volumes of IRCs, PED and RV are displayed separately and three-dimensionally.Treatment succeeded in an immediate decrease of RV within the first weeks(p<0,01) followed by a slower reduction of PEDV (p<0,01). The decrement of PEDV continues up to month 3. The basis of the PED is less influenced in the first weeks but is significantly (p<0,05) reduced after month 2.

Conclusions:: RV and height of the PED reacts faster to Ranibizumab than the basal area of the PED. Distinct changes in the retinal microstructure can be visualized and may play a role in the early recognition of nAMD relapse in future. The different time course of the parameters evaluated in this study might give new insights into restitution of sensory retina and pigment epithelium after Ranibizumab treatment. HD-OCT clearly improves the clinical monitoring of disease progression and analysis of treatment benefit in anti-angiogenic therapy.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age-related macular degeneration • imaging/image analysis: clinical