Comparison between fixed-angle and customised corneal-polarisation compensation methods in scanning laser polarimetric measurement of the retinal nerve fibre layer in glaucoma.
OBJECTIVE
To investigate the differences between the results of scanning laser polarimetric (SLP) measurements of the retinal nerve fibre layer thickness (RNFLT) made using two different corneal-polarisation techniques; customised (SLP-C), and fixed-angle (SLP-F) compensations.


METHODS
Both SLP-C and SLP-F were performed on 37 consecutive phakic patients with chronic open-angle glaucoma, and on 14 healthy control subjects. One randomly selected eye per subject was evaluated.


RESULTS
Both SLP-C and SLP-F parameters were able to discriminate between the glaucoma group and the control group, except in the case of the ellipse modulation, which differed significantly between the two groups with SLP-C (P=0.017), but not with SLP-F (P=0.056). When SLP-C and SLP-F values were compared, inferior maximum thickness and ellipse standard deviation were significantly lower with SLP-C in both groups (P<0.05 for each parameter). Superior maximum thickness was significantly lower in glaucoma with SLP-C than with SLP-F (P=0.006) and tended to be lower with SLP-C than with SLP-F in the control group (P=0.053). In the glaucoma group, it was only with SLP-C that a significant (positive) correlation between the superior maximum thickness and the inferior hemifield mean sensitivity (MS) (r=0.653, P<0.001), and between the inferior maximum thickness and the superior hemifield MS (r=0.420, P=0.023) was found. The other global and sectoral SLP parameters showed significant correlation with the corresponding visual field parameters with both techniques.


CONCLUSIONS
Our findings suggest that SLP measurements with customised compensation provide more realistic results for RNFLT than those made with the conventional fixed-angle compensation.
Katsanos
A
A
1st Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
Kóthy
P
P
Holló
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000503:physiopathology; D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007834:Lasers; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D058609:Visual Field Tests / Q000379:methods; D014794:Visual Fields