An enhancement module to improve the atypical birefringence pattern using scanning laser polarimetry with variable corneal compensation.
OBJECTIVE
To examine the repeatability and effect of an enhancement module on the severity of atypical birefringence patterns (ABP) using scanning laser polarimetery (SLP) with variable corneal compensation (VCC).


METHODS
16 patients with perimetric glaucoma (PG), 24 glaucoma suspect and pre-perimetric glaucoma (GSPPG), and 12 normal volunteers (N) were included. One randomly selected eye of each volunteer was scanned three times using VCC and enhanced corneal compensation (ECC) at the same session by the same examiner. Typical scan scores (TSS) were calculated to evaluate the ABP. Coefficients of variability (CoV), coefficients of repeatability (CoR), and intraclass correlation coefficients (ICC) were calculated.


RESULTS
The mean TSS using ECC (n = 97.3 (5.5), GSPPG = 98.3 (3.5), PG = 99.2 (2.3)) was significantly higher (p = 0.02, 0.01, and 0.006, respectively) compared with VCC (86.5 (14.4), 88.2 (18.2), and 83.4 (2.2), respectively). VCC parameters had a CoR of 1.2-6.5, CoV of 1.9%-8.6%, and ICC of 0.8-0.9. ECC parameters had a CoR of 0.5-4.0, CoV of 0.3%-5.1%, and ICC of 0.2-0.9. TSNIT average was the overall best performing parameter with the highest repeatability and least variability using both techniques (CoR<2.1, CoV<2%).


CONCLUSIONS
The enhancement module significantly reduced the severity of ABP and maintained a high level of repeatability of retardation measurements.
PhD, Bascom Palmer Eye Institute, 7108 Fairway Drive, Suite 340, Palm Beach Gardens, FL 33418, USA. msehi@med.miami.edu
M
M
Sehi
D C
DC
Guaqueta
D S
DS
Greenfield
D000328:Adult; D000368:Aged; D000465:Algorithms; D001718:Birefringence; D003315:Cornea / Q000473:pathology; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007834:Lasers; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods; D011446:Prospective Studies; D015203:Reproducibility of Results; D058609:Visual Field Tests; D014794:Visual Fields