Comparison of scanning laser polarimetry and optical coherence tomography in quantitative retinal nerve fiber assessment

Abstract

Purpose: To investigate the relationship between retinal nerve fiber layer (RNFL) measurements in corresponding areas obtained with scanning laser polarimetry and optical coherence tomography and to compare their discriminating ability in the diagnosis of preperimetric and perimetric glaucoma.

Patients and methods: Three hundred eighty-six subjects-57 healthy controls, 145 ocular hypertensive patients, 89 with preperimetric glaucoma, and 95 with perimetric glaucoma-were recruited from the Erlangen Glaucoma Registry. Perimetry, 24-hours intraocular pressure profile, stereographic optic disc slides, optical coherence tomography StratusOCT, and scanning laser polarimetry GDx VCC (Carl Zeiss Meditec, Inc, Dublin, CA) were performed in all patients. Receiver operating characteristic (ROC) curves were constructed for mean RNFL values, sector data, and indices. Sensitivity was estimated at >or=90% and >or=80% of specificity to compare the discriminating ability of each imaging modality.

Results: For discrimination between glaucomatous and healthy eyes in GDx VCC the nerve fiber index demonstrated the largest area under the ROC curve (AUROC) (0.962+/-0.013), whereas in StratusOCT the largest AUROC (0.986+/-0.006) was found in the inferior quadrant. For preperimetric glaucoma detection the nerve fiber index achieved the largest AUROC (0.783+/-0.037). In contrast, the total RNFL average obtained using StratusOCT showed the largest AUROC (0.904+/-0.025). Bland-Altman plots showed good agreement between both instruments.

Conclusions: Both the GDx VCC and StratusOCT demonstrate increasing RNFL loss with advanced glaucomatous damage and were comparable in the diagnosis of perimetric glaucoma. Preperimetric glaucomatous damage may be better assessed by StratusOCT.