PRECIS: Two novel, quantitative metrics, and one traditional metric, were able to distinguish between many, but not all healthy and glaucomatous eyes in the bottom 5th percentile of global circumpapillary retinal nerve fiber layer (cpRNFL) thickness. PURPOSE: To test the hypothesis that objective OCT measures can distinguish between a healthy control with global circumpapillary retinal nerve fiber layer (cpRNFL) thickness within the lower 5% of normal and a glaucoma patient with an equivalent cpRNFL thickness. PATIENTS METHODS: 37 healthy eyes from over 700 normative eyes fell within the bottom 5th percentile in global cpRNFL thickness. The global cpRNFL thickness of 35 glaucomatous eyes from 188 patient eyes fell within the same range. For the traditional methods, the global cpRNFL thickness percentile and the global ganglion cell layer (GCL) thickness percentile, for the central±8°, were calculated for all 72 eyes. For the novel cpRNFL method, the normalized root-mean-square (RMS) difference between the cpRNFL thickness profile and the global-thickness-matched normative thickness profile was calculated. For the superior-inferior (SI) GCL method, the normalized mean difference in superior and inferior GCL thickness was calculated for the central ±8°. RESULTS: The best quantitative metric, the RMS cpRNFL method, had an accuracy of 90% compared to 81% for the SI GCL and 81% for the global GCL methods. As expected, the global cpRNFL had the worst accuracy, 72%. Similarly, the RMS cpRNFL method had an area under the curve (AUC) of 0.93 compared to 0.83 and 0.84 for the SI GCL and global GCL methods, respectively. The global cpRNFL method had the worst AUC, 0.75. CONCLUSION: Quantitative metrics can distinguish between most of the healthy and glaucomatous eyes with low global cpRNFL thickness. However, even the most successful metric, RMS cpRNFL, missed some glaucomatous eyes.
Department of Psychology, Columbia University, Schermerhorn Hall, 1190 Amsterdam Ave #406, New York, NY, USA 10027 Department of Biomedical Engineering, Duke University, Durham, NC, USA, 27798 Bernard and Shirlee Brown Glaucoma Research Laboratory, Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Medical Center, 635 W 165th St, New York, NY, USA 10032 Einhorn Clinical Research Center, New York Eye and Ear Infirmary of Mount Sinai, 310 E. 14th Street South Building, 5th Floor New York, NY, USA 10003.Full article