Abstract:
To determine and compare the accuracy of GDx VCC scanning laser polarimetry (SLP), HRT I confocal scanning laser ophthalmoscopy (CSLO), and clinical assessment of stereoscopic optic disc photographs for diagnosing glaucoma.
One eye each of 40 healthy subjects, 48 glaucoma patients, and 6 patients with ocular hypertension were measured with SLP and CSLO. In addition, simultaneous stereoscopic optic disc photographs were obtained in these eyes. Sixteen photographs of healthy and glaucomatous eyes were duplicated for assessing intraobserver agreement. Four glaucoma specialists, 4 general ophthalmologists, 4 residents in ophthalmology, and 4 optometrists classified the photographs as normal or glaucoma. For SLP, the Nerve Fiber Indicator (NFI) was analyzed. For CSLO, the Moorfields Regression Analysis (MRA) and the Bathija linear discriminant function (LDF) were used.
As has been shown in the Table, SLP had the highest diagnostic accuracy, followed by CSLO Bathija LDF. Glaucoma specialists had a similar accuracy for diagnosing glaucoma as CSLO MRA. Residents had the lowest diagnostic accuracy. The intraobserver agreement (kappa) for classifying the photographs ranged between 0.48 (within residents) and 0.78 (within glaucoma specialists). The interobserver agreement ranged between 0.45 (between residents) and 0.74 (between glaucoma specialists). The agreement between observers and CSLO MRA (kappa, 0.68) was statistically significantly higher (P < 0.001; paired t test) than between observers and SLP NFI (kappa, 0.60) and CSLO Bathija LDF (kappa, 0.62), suggesting that the latter two may be of added value to the clinician.
Automated analysis of measurements with GDx VCC and HRT I had a higher diagnostic accuracy for glaucoma than classification of stereoscopic optic disc photographs by glaucoma specialists, general ophthalmologists, residents in ophthalmology, and optometrists. The intra– and interobserver agreement for optic disc analysis was only moderate to good. We think imaging techniques may assist clinicians in managing glaucoma.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • optic disc