Macular Ganglion Cell Layer Imaging in Preperimetric Glaucoma with Speckle Noise-Reduced Spectral Domain Optical Coherence Tomography

Objective: To visualize the macular ganglion cell layer (GCL) and measure its thickness in normal eyes and eyes with preperimetric glaucoma, using speckle noise-reduced spectral domain optical coherence tomography (SD-OCT). Design: Retrospective consecutive case series. Participants: Thirty-seven eyes of 37 patients with preperimetric glaucoma and 39 normal eyes of 39 volunteers. Methods: Vertical and horizontal SD-OCT B-scan images were acquired with minimal speckle noise by using eye-tracking to obtain and average 50 B-scans at each identical location of interest. B-scan images were manually analyzed for GCL, retinal nerve fiber layer (RNFL), and inner plexiform layer shapes and thicknesses in the macula. Main Outcome Measures: Macular GCL images and thickness in normal eyes and in eyes with preperimetric glaucoma. Results: The macular GCL was clearly seen on speckle noise-reduced SD-OCT images in normal eyes and eyes with preperimetric glaucoma. In each eye with preperimetric glaucoma, thinning of the macular GCL was visually apparent, particularly on vertical scans. The mean regional macular GCL was most severely thinned in the inferior perifoveal region, where its thickness was <70% of its normal thickness in 30 (81.1%) of the 37 eyes and <50% of its normal thickness in 13 (35.1%) of the 37 eyes. When the sensitivity and specificity for detecting abnormal thinning (outside the lower limit of 99% confidence interval [CI] for the means in the 39 normal eyes) in at least one 0.5-mm segment or sector were compared, the macular GCL on vertical B-scans exhibited higher sensitivity (81.1%) than the other layers on vertical B-scans (99% CI, 5.4%-59.5%; P = 0.00075-0.02100), the macular GCL (99% CI, 40.5%; P = 0.00027) on horizontal B-scans, the other layers (99% CI, 5.4%-48.6%; P<0.00048-0.00400) on horizontal B-scans, and circumpapillary RNFL automatically measured on SD-OCT (54.1%; P = 0.021), and scanning laser polarimetry with variable corneal compensation (24.3%; P = 0.00095). All the macular layers on both the vertical and horizontal B-scans and circumpapillary RNFL thickness exhibited comparable specificity (91.4-100.0%, statistically not different). Conclusions: Speckle noise-reduced SD-OCT imaging allowed clear visualization and measurement of the macular GCL, which was severely thinned in eyes with preperimetric glaucoma. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2011; 118: 2414-2426 (C) 2011 by the American Academy of Ophthalmology.