Evaluation of the Inter–Eye Symmetry Parameter Using the Scanning Laser Polarimeter With Variable Corneal Compensation in the Diagnostic Innovations in Glaucoma Study

Abstract

 

Abstract:

 

To evaluate the ability of the Inter–Eye Symmetry parameter of the scanning laser polarimetry with variable corneal compensation (GDx VCC) to discriminate between individuals with normal visual fields (VF) and normal optic disc photographs and individuals with abnormal VFs and/or abnormal optic disc photographs.

 

85 control subjects with normal visual fields and optic disc photographs in both eyes without regard to their intraocular pressure level were included in the study. In addition, 168 subjects with either two consecutive abnormal visual fields (SITA–SAP) in either eye and/or an abnormal optic disc photograph by consensus in either eye were included. All subjects had been tested with the GDx VCC in both eyes. ROC curves were calculated for Inter–Eye Symmetry, TSNIT average, Superior average, Inferior average, TSNIT standard deviation, and Nerve Fiber Indicator (NFI) to assess discrimination between subjects with different combinations of VF and/or optic disc abnormalities and control subjects. For each parameter, the control group was compared to 1) subjects with abnormal VFs in both eyes (n=61), 2) subjects with abnormal VFs in only one eye (n=63), 3) subjects with abnormal optic disc in both eyes (n=102), and 4) subjects with abnormal optic discs in only one eye (n=29). In subjects with two abnormal eyes, ROC curves were calculated for each eye separately.

 

The NFI parameter ranked best compared to the other parameters. For subjects with two abnormal eyes, the ROC curves are presented for the right eye only in the table.

 

Discriminating between the control eyes and eyes with abnormal VFs and/or abnormal optic discs was not improved with the Inter–Eye Symmetry parameter compared to other available eye specific parameters. Overall, the NFI performed better than the other parameters.

 

 

 

Keywords: nerve fiber layer • optic disc • imaging/image analysis: clinical