Skenirajoča laserska polarimetrija: občutljivost in specifičnost parametra "števila" v diagnostiki glavkoma
Scanning laser polarimetry: "number" parameter sensitivity and specificity in glaucoma diagnostics

slovenian

2005

volume 74, issue 10

Diagnosis   diagnostika   Glaucoma, Open-Angle   Microscopy, Confocal   Roc Curve

Slovensko zdravniško društvo
(Obvezni izvod spletne publikacije)

Background. Scanning laser polarimetry (SLP) is a method that enables quantitative assessment of retinal nerve fibre layer (RNFL) thickness surrounding the optic nerve. The commercially available device GDx (GDx, LaserDiagnostics Technologies, San Diego, CA) yields an outprint consisting ofa reflectance image, colour-coded retardation map, and the 14 parameters, ofwhich the "Number" was shown to be the single best parameter to discriminatebetween glaucomatous and normal eyes. The "Number" ia a probabitity score, ranging from 1 (low probability of glaucoma) to 100 (high probability of glaucoma). In our study we determined the sensitivity and specificity of the "Number" at cutoff values of 23 and 30. Methods. Thirty patients with different stage of glaucoma and 14 patients with typical glaucomatous changes of the ONH without visual field loss (preperimetric glaucoma) were included in the analysis. The control group was represented by 27 adults without ocular pathology with intraocular pressure of < 21 mm Hg andnormal visual fields. The sensitivity and specificity of the "Number" was determined at a cut-off level of 23 and 30. Results. The sensitivity of the "Number" at a cut-off level 30 for the glaucoma group was 74% at a specificityof 86%, at a cut-off of 23 the sensitivity increased to 83% at a specificity of 76%. The discriminating ability of the "Number" in the group with preperimetric glaucoma was low, with the sensitivities of 36% and 50% at a cut-off value of 30 and 23, respectively. Conclusions. The parameter "Number" yielded good separation between normal eyes and eyes with moderate and advanced glaucoma. However, the sensitivity of the "Number" in eyes with mild glaucoma and especially with preperimetric glaucoma was low. Because of the great interindividual variability of the RNFL, the assessment of RNFL thickness change over time would be more appropriate to detect early glaucomatous changes.

10.04.2014