Evaluation of retinal nerve fiber layer with optic nerve tracking optical coherence tomography in thyroid-associated orbitopathy.

AIMS: To evaluate retinal nerve fiber layer (RNFL) thickness in eyes with Graves' orbitopathy (GO), in eyes with ocular hypertension (OHT) and in a control group of healthy eyes.

METHODS

Observational, controlled cross-sectional study. We evaluated all patients with primary open-angle glaucoma (POAG) and all patients with GO and intraocular pressure >23 mm Hg in primary position examined from March 2006 to June 2007. Forty apparently healthy patients (80 eyes) were enrolled as a control group. Complete ophthalmic evaluation, visual field (VF) examination with the Humphrey Visual Field Analyzer and RNFL thickness measurement with optic nerve tracking optical coherence tomography (ONT-OCT; OCT/SLO, OTI, Toronto, Ont., Canada) were performed.

RESULTS

Among 116 eyes with POAG [58 patients, 32 males, 26 females, mean age 62 (46-71) years], RNFL was reduced in 87 eyes (75%, p = 0.05) when compared with the control group, and a good correlation was found between RNFL thickness and VF abnormalities (Spearman's rho 0.822; p = 0.001). Among 60 eyes [30 patients, 12 males, 18 females, mean age 56 (50-69) years] with GO and OHT, nonglaucomatous diffuse abnormalities of the VF were detected in 44 eyes (73.3%, p = 0.03), while RNFL thinning was present in 14 eyes (9 patients, 23.3%, p = 0.03). No correlation was found between RNFL thickness and VF abnormalities (Spearman's rho 0.365; p = 0.02). No significant differences in RNFL pattern were present between the group with GO, OHT and RNFL thinning and the group with POAG.

CONCLUSIONS

In patients with GO and OHT, evaluation of RNFL thickness with ONT-OCT may represent an objective diagnostic technique for detecting optic neuropathy.