Quantitative estimation of retinal nerve fiber layer height in glaucoma and the relationship with optic nerve head topography and visual field

Purpose: The authors estimated the retinal nerve fiber layer height (RNFLH) measurements in patients with glaucoma compared with those in age-matched healthy subjects as obtained by the laser scanning tomography and assessed the relationship between RNFLH measurements and optic and visual field status. Methods: Parameters of optic nerve head topography and RNFLH were evaluated in 125 eyes of 21 healthy subjects and 104 patients with glaucoma using the Heidelberg Retina Tomograph ([HRT] Heidelberg Engineering GmbH, Heidelberg, Germany) for the entire disc area and for the superior 70°(50°temporal and 20°nasal to the vertical midline) and inferior 70°sectors of the optic disc. The mean deviation of the visual field, as determined by the Humphrey program 24-2 (Humphrey Instruments, Inc., San Leonardo, CA, U.S.A) was calculated in the entire field and in the superior and inferior Bjerrum area. Result: Retinal nerve fiber layer height parameters (mean RNFLH and RNFL cross-sectional area) were decreased significantly in patients with glaucoma compared with healthy individuals. Retinal nerve fiber layer height parameters was correlated strongly with rim volume, rim area, and cup/disc area ratio. Of the various topography measures, retinal nerve fiber layer (RNFL) parameters and cup/disc area ratio showed the strongest correlation with visual field mean deviation in patients with glaucoma. Conclusion: Retinal nerve fiber layer height measures were reduced substantially in patients with glaucoma compared with age-matched healthy subjects. Retinal nerve fiber layer height was correlated strongly with topographic optic disc parameters and visual field changes in patients with glaucoma.