Evaluation of the Size of Choroidal Neovascular Membrane by Optic Coherence Tomography

Abstract

Abstract: : Purpose: In order to understand the preoperative pathological condition of the choroidal neovascular membrane (CNVM) and to predict the surgical effects of it, the estimated sizes of the CNVM based on the data of preoperative Indocyanine angiography (IA) and optic coherence tomography (OCT) were compared with the true size of CNVM which was obtained during vitreous surgery. Methods: Sixteen eyes of 16 patients (11 males and 5 females) that that undergone vitrectomy with CNVM removal from July of 2001 to August of 2002 in Kumamoto University Hospital were included in this study. CNVMs from 11 eyes were caused by age-related macular degeneration (ARMD), those from 4 eyes were due to idiopathic CNVMs, and that from the remaining eye was due to myopic maculopathy. For all of the16 eyes, IA was performed preoperatively. In addition, 8 eyes out of the 16 eyes were examined with OCT preoperatively. CNVMs specimens were removed by vitrectomy and fixed immediately in a fixative of 4% paraformaldehyde and their sized were measured under a dissection microscope. The sizes of the CNVM obtained via IA and OCT were measured and compared with those from the specimens. Results: The area of the CNVM measured by IA were significantly smaller (32 ± 27%; mean ± S.D.) than those of the CNVM specimens. On the other hand, the area of the CNVM from OCT indicated the exact size of the CNVM (124 ± 57%). Conclusions: Using IA, the size of the CNVM reveled as a vascular network might be underestimated due to the difficulty of visualizing the surrounding connective tissues. On the other hand, OCT seems to provide an exact estimation of the size of the CNVM preoperatively. Examination of OCT combined with IA provide qualitative and quantitative information in designing surgical treatment.

Keywords: age-related macular degeneration • choroid: neovascularization • pathology: human