Clinical variables associated with glaucomatous injury in eyes with large optic disc cupping

BACKGROUND AND OBJECTIVE: To characterize the range of retinal nerve fiber layer (RNFL) and standard automated perimetry damage in eyes with large vertical cup-disc ratio (VCDR). PATIENTS AND METHODS: Complete examination, standard automated perimetry, scanning laser polarimetry with variable corneal compensation, and optical coherence tomography (OCT) of the RNFL and optic nerve head were performed. Large VCDR was defined as ≥ 0.80 using stereoscopic disc examination and OCT optic nerve head analysis. Structural and functional characteristics were assessed separately in eyes with a disc area of less than 2 mm², 2 to 2.5 mm² and greater than 2.5 mm². RESULTS: Fifty-seven eyes of 57 subjects were enrolled. A broad range in mean deviation (2.0 to -32.8 dB) and mean RNFL thickness with OCT (24.3-100.4 μm) and scanning laser polarimetry with variable corneal compensation (24.0-61.7 μm) was identified. Predictors of standard automated perimetry severity using multiple linear regression were mean RNFL thickness using OCT (P = .001) and scanning laser polarimetry (P = .001), OCT-vertical cup diameter (P = .003), temporal, superior, nasal, inferior, temporal standard deviation (P = .03), and OCT-disc area (P = .04). Eyes with an OCT-disc area of less than 2 mm ² demonstrated significantly greater standard automated perimetry damage, RNFL loss using OCT and scanning laser polarimetry, and OCT-rim area (P = .002, .0007, .03, and < .0001, respectively) compared with eyes with a disc area of greater than 2.5 mm². CONCLUSIONS: Eyes with large VCDR have a wide range of RNFL atrophy and standard automated perimetry damage. Small optic discs are associated with more advanced glaucomatous injury.