Scanning laser polarimetry with enhanced corneal compensation and optical coherence tomography in normal and glaucomatous eyes

Abstract

Purpose: To examine the association between scanning laser polarimetry (SLP), using enhanced (ECC) and variable corneal compensation (VCC) with optical coherence tomography (OCT), and to compare their discriminating ability in the diagnosis of glaucoma.

Methods: Normal and glaucomatous eyes enrolled from four clinical sites underwent complete examination, automated perimetry, SLP-ECC, SLP-VCC, and OCT. Eyes were characterized in two groups based on the typical scan score (TSS): Normal birefringence pattern (NBP) was defined as a TSS of 80 to 100 and abnormal birefringence pattern (ABP) as TSS <or= 79. For each of the six SLP parameters and five OCT parameters the areas under the receiver operating characteristic curve (AUROCs) were calculated to compare the discriminating ability of each imaging modality, to differentiate between normal and glaucomatous eyes.

Results: Ninety-five normal volunteers and 63 patients with glaucoma were enrolled. Average visual field mean deviation was -4.2 +/- 4.3 dB in the glaucoma group. In eyes with NBP, SLP-ECC had significantly (all P <or= 0.001) greater correlation with OCT average, superior, and inferior retinal nerve fiber layer (RNFL; r = 0.79, 0.67, 0.74) compared with SLP-VCC (r = 0.71, 0.43, 0.37). In eyes with ABP, SLP-ECC had a significantly greater (all P <or= 0.001) correlation with OCT average, superior, and inferior RNFL (r = 0.75, 0.73, 0.83) compared with SLP-VCC (r = 0.51, 0.22, 0.18). The AUROC for OCT inferior average thickness (0.91) was similar (P = 0.26) to the TSNIT (temporal, superior, nasal, inferior, temporal) average obtained using SLP-ECC (0.87) and significantly (P = 0.02) greater than SLP-VCC (0.81).

Conclusions: Compared with SLP-VCC, SLP-ECC has significantly stronger correlations with OCT and may improve the discriminating ability for early glaucoma diagnosis.