Optic Cup Slope as a Numeric Representative of Glaucomatous Cupping

PURPOSE: To objectively define the degree of cupping, the authors extracted 3-dimensional slope surface maps from Cirrus HDTM-OCT data and assessed their differentiating characteristics between normal subjects and glaucomatous patients. METHODS: One eye from each of 40 normal subjects and 1 eye from each of 39 patients with glaucoma were examined using automated visual field perimetry and Cirrus HDTM-OCT. The Optic Disc Cube 200 x 200 protocol was performed. The individual OCT data were reconstructed as the 3-dimensional surface maps of the optic disc cup and the slope of each contour was calculated using custom-developed software. Several disc cup slope parameters were derived. The parameters measuring the internal features of the optic disc cup were calculated and compared between groups. RESULTS: Sum of cup slope, sum of thresholded cup slope, and sum of thresholded cup slope / thresholded cup area parameters were differentiating factors between the normal and glaucoma groups (p < 0.05). The area under the receiver operating characteristic curve (AUROC) value of the slope parameters ranged from 0.718 to 0.753. The sum of thresholded cup slope / thresholded cup area parameter was well correlated with visual field mean deviation (r = -0.250, p = 0.028). CONCLUSIONS: The optic disc cup slope parameter obtained with OCT may be a useful parameter for representing glaucomatous cupping.

Correlation of Progression Rate between Optic Disc Cupping and Visual Field Damage in Treated Primary Open Angle Glaucoma

PURPOSE: To know the rate of optic disc cupping and visual field progression with correlation among them, and identify clinical factors associated with them. METHODS: Forty patients with POAG who treated over 10 years were evaluated, Cup progression rate was evaluated by using computer-aided planimetry and visual field declination was evaluated with Goldmann perimetry and manual grid template system. Optic disc cupping and visual field progression correlations were estimated using linear regression and all related clinical factors were evaluated using a multiple regression model. RESULTS: Optic disc cupping progression started from inferotemporal to superonasal, to superotemporal and to inferonasal portion (total 0.0067/year) and visual field loss progressed superonasal, inferonasal, superotemporal, inferotemporally (total -1.07%/year) in order with significant correlation. Incisional surgery before visit and higher yearly average higher intraocular pressure showed faster optic disc cup progression and higher initial intraocular pressure and lesser antiglaucoma medications at initial visits showed faster visual field progression. CONCLUSIONS: In treated patients with POAG, the rate of disc cupping and visual field decline showed slow progression rate with significant correlation and various clinical factors affected.