Eyes with retinitis pigmentosa show reduced RNFL thickness

Patients with retinitis pigmentosa may also have retinal nerve fiber layer thinning, according to a study by researchers in Chicago.

Gerald A. Fishman, PhD, and colleagues at the University of Illinois used optical coherence tomography to investigate peripapillary retinal nerve fiber layer (RNFL) thickness in 25 eyes of 25 retinitis pigmentosa patients who averaged 48.6 years of age. They published their results in the October issue of Investigative Ophthalmology and Visual Science.

The researchers acquired circular scans of the optic nerve measuring 3.46 mm in diameter, which were obtained for the temporal, superior, nasal and inferior quadrants of each eye, according to the study.

Three smaller segments were also measured within each quadrant, the authors noted.

Investigators found that 10 patients had abnormal thinning of the peripapillary RNFL in two or more segments. In addition, seven of these 10 patients had abnormal thinning in at least one 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," the authors said.

The researchers found no association between the remaining visual field and presence of an RNFL defect, they noted.

"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," the authors said.