Evaluation of choroidal thickness in retinitis pigmentosa using enhanced depth imaging optical coherence tomography

To describe the choroidal characteristics of patients with retinitis pigmentosa (RP) using enhanced depth imaging (EDI) and spectral domain (SD) optical coherence tomography (OCT).

To investigate the spectral-domain ocular coherence tomography features of the choroid in patients with RP using EDI.

A prospective, case-control study of 21 patients from the Cole Eye Institute with RP imaged using the Spectralis OCT and an EDI protocol. Submacular choroidal thickness measurements were obtained beneath the fovea and at 500 µm intervals for 2.5 mm nasal and temporal to the centre of the fovea. These measurements were compared to choroidal thickness measurements from 25 healthy age-matched controls with similar refractive error range and no clinical evidence of retinal or glaucomatous disease. Statistical analysis was performed to compare choroidal thickness at each location between the two groups and to correlate choroidal thickness with best-corrected visual acuity and central retinal thickness.

Mean ages were 40.6 years for control patients and 45.1 years for RP patients (p>0.05). Mean choroidal thickness measurements were 245.6±103 µm in RP patients and 337.8.2±109 µm in controls (p<0.0001). There was no correlation between subfoveal choroidal thickness and visual acuity or retinal thickness in the RP patients when compared to the control group.

Submacular choroidal thickness, as measured by SD-OCT EDI, is significantly reduced in patients with RP, but did not correlate with visual acuity or retinal thickness in RP patients. Further research is needed to understand better  the pathophysiological significance of the choroidal alterations present in RP.