Peripapillary Retinal Nerve Fiber Layer and Ganglion Cell–Inner Plexiform Layers Thickness in Ankylosing Spondylitis

Abstract

Objective: To assess the thickness of the retinal nerve fibril layer (RNFL) in cases with ankylosing spondylitis (AS).Materials and methods: The study included 40 AS patients who had no history of acute and/or previous uveitis and 50 healthy controls. After detailed ocular examination, the thickness of the peripapillary RNFL, the macula, and the ganglion cell–inner plexiform layers (GCIPL) were measured by spectral domain optic coherence tomography (SD-OCT). The correlation between the duration of the disease and the thickness of the RNFL, the macula, and the GCIPL were analyzed in the patients who had AS. These patients were then placed into 2 groups according to their BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) score: patients with BASDAI score <4 and those with BASDAI score ≥4. The correlations between the BASDAI score and the mean GCIPL and temporal RNFL thickness were evaluated.Results: No significant difference was detected in the RNFL thickness of the AS patients and that of the controls (p = 0.407). Nor was any significant difference detected in the GCIPL thickness of the AS and the control groups (p = 0.091). In addition, no significant difference was found in the macular thickness when the AS group was compared to the control group (p = 0.139). However, a negative correlation was detected between the duration of the disease and the thickness of the temporal quadrant RNFLs (r = −0.334; p = 0.035). The temporal quadrant RNFL thickness and the mean thickness of the GCPIL were significantly thinner in the AS patients with BASDAI score ≥4 (p = 0.034 and p = 0.025, respectively). Also, the BASDAI score were negatively correlated to the temporal quadrant RNFL and GCIPL thickness (r = −0.332; p = 0.036 and r = −0.348; p = 0.028, respectively).Conclusion: RNFL thickness and GCIPL thickness of ankylosing spondylitis may be affected by the severity and duration of the disease.