Comparison between GDx VCC parameter and achromatic perimetry in glaucoma patients.
OBJECTIVE
To evaluate the correlation between polarimetry parameters and standard threshold perimetry indices.


METHODS
One hundred and eight consecutive glaucomatous patients were recruited in this study. Glaucomatous patients were classified when an abnormal visual field and/or an abnormal optic nerve head were present. One eye was chosen randomly from all the subjects. All optic nerve heads were examined with the GDx variable corneal compensator (VCC) (Laser Diagnostic Technologies, Inc, San Diego, CA) and visual fields were assessed by Humphrey Perimeter, program 24-2, SITA standard (Humphrey Instrument, Inc, San Leandro, CA). GDx VCC parameters and visual field indices were considered. Correlation coefficient was used to compare the 2 sets of data. A linear regression model was also used to calculate the independent contribution of each GDx VCC parameter and to determine which parameter was the most predictive of visual field damage.


RESULTS
The mean age (+/-standard deviation) was 61+/-10.3, the average of the mean deviation (MD) was -2.31+/-3.2 dB and the mean pattern standard deviation (PSD) was 3.32+/-2.83 dB. Significant (P<0.05) correlation was found between MD and the nerve fiber indicator (NFI) (r=-0.35), the superior average (r=0.28), the Temporal-Superior Nasal-Inferior Temporal average (r=0.24) and the inferior average (r=0.21). The linear regression model found NFI to be the predictor variable of MD. Significant (P<0.05) correlation was found between PSD and the NFI (r=0.39), the superior and the inferior average (r=0.30), and the Temporal-Superior Nasal-Inferior Temporal average (r=0.29). The linear regression model found NFI to be the predictor variable of PSD.


CONCLUSIONS
Some of the GDx VCC indices were significantly correlated to visual field indices in glaucomatous patients, but NFI was the best indicator of visual field damage.
Iester
Michele
M
Department of Neurological Sciences, Ophthalmology, Genetic, Clinica Oculistica, University of Genoa, Genoa, Italy. iester@unige.it
Perdicchi
Andrea
A
De Feo
Fabio
F
Fiesoletti
Enrica
E
Amodeo
Stefano
S
Sanna
Giuseppe
G
Leonardi
Antonella
A
Calabria
Giovanni
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007834:Lasers; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D011446:Prospective Studies; D012372:ROC Curve; D012029:Refraction, Ocular; D012160:Retina / Q000473:pathology*; D012720:Severity of Illness Index; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields