Evaluation of Retinal Nerve Fiber Layer Thickness in Retinitis Pigmentosa Patients Using Spectral-Domain OCT

PURPOSE: To measure the peripapillary retinal nerve fiber layer (RNFL) thickness using spectral-domain optical coherence tomography in patients with retinitis pigmentosa. METHODS: Fifty eyes of 30 patients with retinitis pigmentosa underwent a complete ocular examination, including best-corrected visual acuity using a Snellen chart, slit-lamp biomicroscopic examination, and Goldmann applanation intraocular pressure measurement. Dilated fundus examination was performed using both direct and indirect ophthalmoscopy. In addition, all patients underwent peripapillary RNFL thickness measurements using an OPKO spectral-domain optical coherence tomography (OPKO Instrumentations, Miami, FL). RESULTS: The mean (± SD) age of the study cohort was 45.8 (± 16.3) years. Of the 50 eyes, 18 (36%) showed a thinning of the peripapillary RNFL in 1 or more quadrants and 21 (42%) showed a thickening of the peripapillary RNFL in 1 or more quadrants. Four eyes (8%) showed both thinning and thickening of the peripapillary RNFL thickness. The overall circumferential RNFL thickness of the 14 eyes that showed only thinning in at least 1 quadrant was 78.78 μm. For the 17 eyes that showed only thickening in at least 1 quadrant, the RNFL thickness was 119.69 μm. The values of the eyes with thinning and the eyes with thickening were significantly different from normal (t = 6.31 and P < 0.01 for thickening; t = 3.62 and P < 0.01 for thinning). CONCLUSION: Using spectral-domain optical coherence tomography testing, we demonstrated in the current study that the peripapillary RNFL thickness in patients with RP can be decreased, increased, or maintained within normal limits. Assessment of the RNFL thickness seems prudent in these patients, particularly for identifying notable degrees of RNFL thinning in those being considered for future therapeutic trials.