Abstract
Purpose: :
. To compare the ability of time-domain and spectral-domain optical coherence tomography (OCT) to discriminate between normal and glaucomatous eyes.
Methods: :
. Normal volunteers and glaucoma patients underwent complete eye examination, standard automated perimetry (SAP), optic disc photography, and time and spectral-domain OCT. One eye per subject was enrolled. Inclusion criteria consisted of best corrected visual acuity of at least 20/40, refractive error between -8.00D and +4.00D, age between 40 and 79 years, and reliable standard automated perimetry (SAP). Glaucomatous eyes had neuroretinal rim atrophy and corresponding SAP defect. OCT scans were acquired using a 3.4-mm scan diameter. The average of two scans was used for the analysis. For each of five retinal nerve fiber layer (RNFL) thickness parameters (average, temporal, superior, nasal and inferior) areas under the receiver operator characteristic curve (AUROC) were calculated to compare the discriminating ability between normal and glaucomatous eyes.
Results: :
. Thirty-two normal (mean age 62.63±10.3 years) and 33 persons with glaucoma (mean age 67.2±8.4 years, average SAP mean deviation -8.6±6.7 dB) were enrolled. There was no difference (p=0.53) in age between the normal and glaucomatous groups. Normal eyes had significantly greater (p<0.001) mean average RNFL thickness using spectral domain OCT (105.5±12.7) compared to time-domain OCT (97.5±9.6), and significantly lesser (p=0.002, p<0.001 respectively) mean superior and inferior RNFL thickness using spectral domain OCT (108.4±15.8; 103.0±12.5 respectively) compared to time-domain OCT (117.0±17.3; 127.5±16.2 respectively). No differences were observed in glaucomatous eyes (p>0.05) for superior and inferior, but the average RNFL thickness was significantly greater (p<0.001) using spectral domain OCT (77.0±17.8) compared to time domain OCT (70.2±18.3). AUROC values for average, superior, inferior, nasal and temporal sectors were similar (p=0.80, p=81, p=0.38, p=0.70, p=0.93 respectively) for spectral-domain OCT (AUROC 0.90, 0.81, 0.93, 0.79, 0.71 respectively) and time-domain OCT (AUROC 0.91, 0.81, 0.95, 0.77, 0.70 respectively).
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • discrimination