Abstract
Purpose: :
To compare diagnostic ability in glaucoma detection between retinal nerve fiber layer (RNFL) thickness measurements obtained by spectral domain optical coherence tomography (OCT) and time domain OCT. Patients and
Methods: :
105 eyes of 105 patients (36 Normal, 33 Ocular Hypertensive and 36 Glaucomatous) underwent a complete examination, standard automated perimetry, TD-OCT (Stratus OCT;Carl Zeiss Meditec) and FD-OCT (RTVue;Optovue Inc.). Areas under the receiver operating characteristic curves (AUROCs) and sensitivity values at a fixed specificity of 95% were calculated and compared for RNFL parameters obtained by both instruments. We also evaluated the diagnostic ability in glaucoma detection of the "ganglion cell complex " parameter (GCC) available on SD-OCT. Agreement between RNFL measurements was evaluated by means of Bland-Altman plots.
Results: :
The average (AUC, 0.94 SD-OCT and 0.92 Stratus OCT), superior (AUC, 0.90 and 0.90, respectively), and inferior (AUC, 0.92 and 0.87, respectively) RNFL thicknesses showed the best AUROCs with no significant difference between the two OCT devices (P>0.05). FD-OCT showed higher sensitivity at 95% specificity (64% to 81%) than TD-OCT (61% to 69%). The FD-OCT parameter GCC thickness showed AUROCs 0.93 to 0.95 and sensitivities at 95% specificity 75% to 81%. Average, Superior, Inferior, Nasal and Temporal RNFL thicknesses measurements were significantly higher in FD-OCT than in TD-OCT measurements in the Bland-Altman plots (P<0.001).
Conclusions: :
While FD-OCT and TD-OCT have comparable diagnostic performance in glaucoma detection, Fourier domain technology seems to be a better diagnostic tool in a clinical setting, because it is user-friendly, repeatable and in most of patients examination does not require pupil dilatation. GCC thickness measurements show excellent diagnostic validity and may be a promising parameter in the clinical assessment of glaucoma. RNFL thickness measurements obtained from the two OCT technologies may not be used interchangeably.
Keywords: imaging/image analysis: clinical • optic disc • nerve fiber layer