Retinal nerve fiber layer defects in RP patients

PURPOSE. TO determine, with the use of optical coherence tomography (OCT), the peripapillary retinal nerve fiber layer (RNFL) thickness among patients with retinitis pigmentosa (RP) of different degrees of disease severity. METHODS. One eye in each of 25 RP patients was included. All patients underwent complete ocular examination, including the measurement of intraocular pressure, corneal thickness, and detailed fundus examination. Visual fields were evaluated by Goldmann perimetry. An RNFL thickness protocol was used to acquire circular scans of 3.46 mm in diameter around the optic nerve. For each eye, RNFL thickness was studied in the temporal (316°-45°), superior (46°-135°), nasal (136°-225°), and inferior (226°-315°) quadrants. Three smaller segments were also measured within each quadrant, all automatically calculated by the existing OCT software. The severity of damage to the peripapillary nerve fiber layer was compared with the clinical appearance of the optic disc, severity of field loss, and mode of inheritance for RP. RESULTS. The mean age of patients included in the study was 48.6 years (range, 23-73 years). Of the 25 patients examined, 10 had abnormal thinning of the peripapillary RNFL in 2 or more segments, and 7 of those had abnormal thinning in at least 1 quadrant. The number of patients with abnormal thinning of the RNFL was considerably greater in those with clinically observed moderately severe or severe pallor of the optic disc than in those with normal appearance or mild pallor of the optic disc. No consistent association was noted between the remaining visual field and the presence of a RNFL defect (P > 0.05). CONCLUSIONS. Patients with retinitis pigmentosa may have a measurable degree of RNFL thinning as determined by OCT. These observations could have an impact on future treatment strategies and imply that patients considered for various treatment options would benefit by an evaluation of nerve fiber layer thickness.