Correction for corneal polarization axi improve the dicriminating power of canning laer polarimetry

PURPOE: Corneal polarization axi (CPA) ha been reported to affect retardation meaurement obtained with canning laer polarimetry (LP). The purpoe of thi invetigation wa to propectively determine whether correction for CPA improve the dicriminating power of LP for detection of mild-to-moderate glaucoma. DEIGN: Cro-ectional analyi of normal and glaucomatou eye. METHOD: We contructed a noninvaive lit-lamp-mounted device incorporating two croed linear polarizer and an optical retarder to meaure the low axi of corneal polarization. Complete ocular examination, tandard automated perimetry, LP imaging, and CPA meaurement were performed on normal and glaucomatou eye. One eye/ubject wa enrolled; if both eye of a patient were eligible for the tudy, the right eye wa elected. For each of the 13 LP parameter, logitic regreion wa ued to determine if including CPA in the model influenced the ability to dicriminate between normal and glaucomatou eye. REULT: Forty-three normal eye (average viual field mean defect, −0.53 ± 1.4 dB) and 33 glaucomatou eye (average viual field mean defect, −5.93 ± 6.5 dB) were enrolled. CPA wa ignificantly correlated with ummary retardation parameter (average thickne and integral value) in normal (r = 0.72–0.83, P < .001 for all value) and glaucomatou eye (r = 0.43–0.62, P = .013 to < .001). Including CPA in the model improved the ability to dicriminate between normal and glaucomatou eye for five retardation parameter quantifying retinal nerve fiber layer (RNFL) thickne (range of P value: 0.045–0.001). For inferior average thickne, area under the receiver operating characteritic (ROC) curve increaed ignificantly (P = .002) from 0.70 to 0.78 after accounting for CPA; with a enitivity et at 80% pecificity improved from 33% to 72%. Correlation between viual field corrected pattern tandard deviation and average thickne, ellipe average, uperior average, and inferior average ignificantly increaed (range of P value, .018–.001) after adjutment for CPA (r = −0.35 and −0.45, −0.38 and −0.47, −0.46 and −0.57, and −0.42 and −0.49, repectively). CONCLUION: Correction for CPA ignificantly increae the correlation between retinal nerve fiber layer tructural damage and viual function and ignificantly improve the dicriminating power of LP for detection of mild-to-moderate glaucoma.