The purpose of the study was to determine whether there are different patterns of retinal nerve fiber layer (RNFL) thinning as measured by spectral domain optical coherence tomography (SD-OCT) for 4 subtypes of open angle glaucoma (OAG): primary OAG (POAG), normal tension glaucoma (NTG), pseudoexfoliation glaucoma (PXG), and pigmentary glaucoma (PDG) and to compare them with normal controls.
SD-OCT RNFL thickness values were measured for 4 quadrants and for 4 sectors (ie, superior-nasal, superior-temporal, inferior-nasal, and inferior-temporal). Differences in RNFL thickness values between groups were analyzed using analysis of variance. Paired t tests were used for quadrant comparisons.
Two hundred eighty-five participants (102 POAG patients, 33 with NTG, 48 with PXG, 13 with PDG, and 89 normal patients) were included in this study. All 4 subtypes of OAG showed significant RNFL thinning in the superior, inferior, and nasal quadrants as well as the superior-temporal and inferior-temporal sectors (all P-values <0.0001) compared with normals. POAG and NTG patients had greater RNFL thinning inferiorly and inferior-temporally than superiorly (P-values: 0.002 to 0.018 and 0.006, respectively) compared with PXG patients. In contrast, PDG patients had greater RNFL thinning superiorly and superior-nasally than inferiorly compared with other OAG subtypes (ie, POAG, NTG, PXG groups, with P-values: 0.009, 0.003, 0.009, respectively). Of the 4 OAG subtypes, PXG patients exhibited the greatest degree of inter-eye RNFL asymmetry.
This study suggests that SD-OCT may be able to detect significant differences in patterns of RNFL thinning for different subtypes of OAG.
*Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Glaucoma Service
‡Schepens Eye Research Institute, Harvard Medical School, Boston
Departments of †Biomedical Engineering and Biotechnology
§Electrical and Computer Engineering, University of Massachusetts, Lowell, MA
Disclosure: The authors declare no conflict of interest.
Reprints: Teresa C. Chen, MD, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Glaucoma Service, 243 Charles Street, Boston, MA 02114 (e-mail: Teresa_Chen@meei.harvard.edu).
Received September 26, 2015
Accepted July 30, 2016