Scanning laser polarimetry using variable corneal compensation in the detection of glaucoma with localized visual field defects.
OBJECTIVE
To evaluate the ability of scanning laser polarimetry parameters and a novel deviation map algorithm to discriminate between healthy and early glaucomatous eyes with localized visual field (VF) defects confined to one hemifield.


METHODS
Prospective case-control study.


METHODS
Seventy glaucomatous eyes with localized VF defects and 66 normal controls.


METHODS
A Humphrey field analyzer 24-2 full-threshold test and scanning laser polarimetry with variable corneal compensation were used.


METHODS
We assessed the sensitivity and specificity of scanning laser polarimetry parameters, sensitivity and cutoff values for scanning laser polarimetry deviation map algorithms at different specificity values (80%, 90%, and 95%) in the detection of glaucoma, and correlations between the algorithms of scanning laser polarimetry and of the pattern deviation derived from Humphrey field analyzer testing.


RESULTS
There were significant differences between the glaucoma group and normal subjects in the mean parametric values of the temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and TSNIT standard deviation (SD) (P<0.05). The sensitivity and specificity of each scanning laser polarimetry variable was as follows: TSNIT, 44.3% (95% confidence interval [CI], 39.8%-49.8%) and 100% (95.4%-100%); superior average, 30% (25.5%-34.5%) and 97% (93.5%-100%); inferior average, 45.7% (42.2%-49.2%) and 100% (95.8%-100%); and TSNIT SD, 30% (25.9%-34.1%) and 97% (93.2%-100%), respectively (when abnormal was defined as P<0.05). Based on nerve fiber indicator cutoff values of > or =30 and > or =51 to indicate glaucoma, sensitivities were 54.3% (50.1%-58.5%) and 10% (6.4%-13.6%), and specificities were 97% (93.2%-100%) and 100% (95.8%-100%), respectively. The range of areas under the receiver operating characteristic curves using the scanning laser polarimetry deviation map algorithm was 0.790 to 0.879. Overall sensitivities combining each probability scale and severity score at 80%, 90%, and 95% specificities were 90.0% (95% CI, 86.4%-93.6%), 71.4% (67.4%-75.4%), and 60.0% (56.2%-63.8%), respectively. There was a statistically significant correlation between the scanning laser polarimetry severity score and the VF severity score (R2 = 0.360, P<0.001).


CONCLUSIONS
Scanning laser polarimetry parameters may not be sufficiently sensitive to detect glaucomatous patients with localized VF damage. Our algorithm using the scanning laser polarimetry deviation map may enhance the understanding of scanning laser polarimetry printouts in terms of the locality, deviation size, and severity of localized retinal nerve fiber layer defects in eyes with localized VF loss.
Kook
Michael S
MS
Department of Ophthalmology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea. mskook@amc.seoul.kr
Cho
Hyun-soo
HS
Seong
Mincheol
M
Choi
Jaewan
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001718:Birefringence; D016022:Case-Control Studies; D003315:Cornea / Q000502:physiology; D003941:Diagnostic Techniques, Ophthalmological; D005188:False Negative Reactions; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D007834:Lasers; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009798:Ocular Hypertension / Q000175:diagnosis; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis*; D014794:Visual Fields