pISSN: 1011-8942 eISSN: 2092-9382 Korean J Ophthalmol 2010;24(1):16-22 DOI: 10.3341/kjo.2010.24.1.16 Original Article Diabetic Retinopathy and Peripapillary Retinal Thickness Hee Yoon Cho1, Dong Hoon Lee2, Song Ee Chung2, Se Woong Kang2 1Department of Ophthalmology, Hanyang University College of Medicine, Seoul, Korea 2Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea Purpose: To assess the diagnostic efficacy of macular and peripapillary retinal thickness measurements for the staging of diabetic retinopathy (DR) and the prediction of disease progression. Methods: In this prospective study, 149 diabetic patients (149 eyes) and 50 non-diabetic control subjects were included. Baseline optical coherence tomography was employed to measure retinal thickness in the macula (horizontal, vertical, and central) and the peripapillary zone (superior, inferior, nasal, and concentric to the optic disc). Seven baseline parameters were correlated with the DR stages identified by fluorescein angiography. Baseline retinal thickness was compared between groups of patients requiring panretinal photocoagulation (PRP) within 6 months (PRP group) and patients not requiring PRP (No-PRP group). Results: Macular and peripapillary retinal thicknesses in diabetic subjects were significantly greater than that in normal controls (p<0.05). All retinal thickness parameters, and particularly peripapillary circular scans, tended to increase with increasing DR severity (p<0.05). The baseline thicknesses of the peripapillary circular scans were greater in the PRP group than in the no-PRP group (p<0.05). Conclusions: Peripapillary retinal thickness may prove to be a useful criterion for DR severity and may also serve as an indicator of disease progression. Key Words: Diabetic retinopathy, Laser photocoagulation, Retina, Mass screening A principal pathogenic mechanism in diabetic retinopathy (DR) is the compromise of the blood-retinal barrier (BRB), leading to retinal edema. Subsequent increases in retinal vol- ume and retinal thickness are relevant quantitative parameters for BRB damage [1]. Traditional methods for evaluating macular thickening, including slit lamp biomicroscopy and stereo fundus pho- tography, are relatively insensitive to small alterations in retinal thickness [2]. Although fluorescein angiography is highly sensitive for the qualitative detection of fluid leak- age, the technique provides no quantitative measure of ei- ther BRB alteration or retinal thickening [3]. Optical coher- ence tomography (OCT), a non-invasive imaging technol- ogy that can generate micrometer resolution cross-sectional imaging of intraocular structures in a few minutes, allows for a quantitative measurement of alterations in retinal Received: September 12, 2008 Accepted: December 28, 2009 Reprint requests to Se Woong Kang. Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, #50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. Tel: 82-2-3410- 3562, Fax: 82-2-3410-0074, E-mail: swkang@skku.edu thickness with good reproducibility [4-6]. Given the increasing diabetic population, a cost-effective and reliable screening program for DR is essential [7-10]. However, interobserver agreement is merely fair for DR grading using fundus photography [11, 12]. Interobserver agreement is even worse for proliferative diabetic retinop- athy (PDR), for which diagnostic accuracy is even more important [13]. In this study, we employed easy-to-use and -reproduce OCT to compare the retinal thicknesses of the macula and the peripapillary zone in order to determine the relation- ship between retinal thickness and DR severity. We also evaluated the validity of baseline retinal thickness for pre- dicting disease progression in DR patients. In particular, we studied which retinal location was best for evaluating the severity of DR and for predicting possible disease progression. Materials and Methods This study was a prospective observational case series, with a study group of type II diabetic patients with or with- ⓒ 2010 The Korean Ophthalmological Society This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses /by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 16