Alteration Ocular Motility in Retinitis Pigmentosa: Case-Control Study

To evaluate ocular motility (OM) disorders and strabismus in a sample of patients with retinitis pigmentosa (RP) and a control sample.

In this cross-sectional retrospective analysis, we studied a sample of RP patients with a mean age of 48.74 years and an average visual acuity of 7/10 based on Snellen optotype and a sample of control patients with similar mean age (49 years [men], 47 years [women]) and sex and an average visual acuity of 9.9/10, with the aim of assessing correlations between alteration of OM and strabismus in RP patients based on age, high refractive defect, or severely impaired binocular vision. The examination followed a protocol of testing for anamnesis and best-corrected visual acuity, as well as a complete eye examination, corneal reflex, cover test, OM, Hess screen, and Lang test.

At the first orthoptic evaluation, 45.16% of patients showed strabismus, 41.93% exotropia (25% of cases intermittent), 3.22% esotropia, and 6.45% vertical deviation. Later evaluation showed strabismus in 25.80% of patients, exotropia in 19.35% (9.67% intermittent), esotropia in 3.22%, and vertical deviation in 3.22%. Assessment of eye motility study showed 51.6% overaction of the inferior oblique and hypofunction of the superior rectus, and 18% overaction of the lateral rectus and hypofunction of the medial rectus. According to our results, alterations in OM and strabismus in RP patients are not correlated with age or high refractive defect. Therefore, motility disorders and strabismus are attributed to a genetic factor to which men are more susceptible.

The incidence of OM disorder was 77.42%, and strabismus was present in 45.16% of patients.