Photoreceptor layer thickness measurement in normal and glaucomatous eyes with spectral domain OCT / 中华实验眼科杂志

ABSTRACT

Background Glaucoma is primarily characterized by the damage of retinal ganglion cells in the inner layer.Whether the outer retinal layers are involved is controversial.Although the functional abnormality of the outer retinal layers have been determined,structural studies present difierent outcomes.Objective This study measured and compared photoreceptor layer thickness between normal and glaucomatous eyes using spectral domain optical coherence tomography(OCT). Methods A case-control study was designed.The macular area of 38 eyes from 38 normal volunteers and 48 primary open-angle glaucomatous eyes(POAG)were imaged by spectral domain OCT(SD OCT).The outer nuclear layer(ONL)and inner and outer segments(IS/OS)layer thicknesses in fovea and parafovea(1.5 mm from the fovea) were measured by a single masked observer using an image analysis software (SigmaScan Pro version 5.0).Retinal nerve fiber layer(RNFL)thicknesses of the 86 eyes were measured by Stratus OCT.The photoreceptor layer thicknesses between normal and glaucomatous eyes were compared.The correlation of photoreceptor with RNFL thicknesses was evaluated with linear and non-linear regression models. Results The outer nuclear layer(ONL)thickness in the fovea in normal and glaucomatous eyes were 96.7±10.7μm and 103.7±13.3 μm,respectively,with a significant difference(P=0.011).The inner and outer segments(IS/OS)layer thicknesses in the fovea in the two groups were 59.3±5.5 μm and 59.5±5.5μm,respectively,without significant difference(P=0.890).The outer nuclear layer(ONL)thicknesses in the parafovea in normal and glaucomatous eyes were 70.9±14.0μm and 68.7 ±10.7μm,respectively,(P=0.410).The inner and outer segments(IS/OS)layer thicknesses in the parafovea in the two groups were 45.2±6.4 μm and 43.6±5.5μm,respectively(P=0.228).The relationship between ONL and RNFL thickness was best described with a second order polynomial regression model assoeiation(Y=-0.019X2+2.73X+10.34,R2=0.211,P=0.005). Conclusion The foveal ONL thickness is increased in glaucomatous eyes.The alteration of foveal ON L thickness is associated with the severity of the disease.