Abstract
Purpose: :
To evaluate the sensitivity and specificity of spectral-domain optical coherence tomography (SD-OCT) to detect localized retinal nerve fiber layer (RNFL) defects in eyes with primary open-angle glaucoma.
Methods: :
Forty-eight patients with open-angle glaucoma who were examined in the glaucoma clinic of Teikyo University School of Medicine Hospital from July 2008 to September 2009 were studied. All patients had RNFL defects which was clearly visible on fundus photographs and were examined with the Optic Disc Cube 200X200 program of the Cirrus high-definition OCT (Cirrus OCT). In addition, fundus photography and standard automated perimetry (SAP) were performed within three-months of the Cirrus OCT examination. The exclusion criteria were; best-corrected visual acuity <0.8, spherical equivalent refractive error > ± 6.0 D, and other diseases known to affect the RNFL thickness or visual field. One eye was randomly chosen when both eyes were eligible. The fundus photographs were used to classify eyes into those with a RNFL defect ≤30 degrees and those with a RNFL defect >30 degrees. When a 30 degree or more abnormality was detected at ≤5% level at the corresponding position of the "clock hours" by the Disc Cube program, the RNFL defect was considered to have been detected by Cirrus OCT.
Results: :
In the 48 eyes, 32/37 (86.5%) hemi-retinas with a RNFL defect ≤30 degrees and 32/32 (100%) hemi-retinas with a >30 degree defect were judged abnormal by Cirrus OCT. Seven of 27 (25.9%) hemi-retinas without a RNFL defect were judged abnormal by Cirrus OCT. Sixty-four of 75 (85.3%) and four of 21 (19.0%) hemi-retinas with a RNFL defect or a SAP abnormality and with neither a RNFL defect or a SAP abnormality were judged abnormal by Cirrus OCT. Based on these results, Cirrus OCT had a sensitivity of 92.8% and a specificity of 74.1% when the RNFL defect was considered to be the standard.
Conclusions: :
The high sensitivity and specificity of the Cirrus OCT to detect RNFL defects especially large defects indicate that SD-OCT can be used for the diagnosis glaucoma.
Keywords: imaging/image analysis: clinical • nerve fiber layer • visual fields