Abstract
Purpose:
To assess cystoid spaces appearing in retinas of patients with retinitis pigmentosa (RP) with or without transcorneal electrical stimulation (TES) demonstrated in spectral domain-optical coherence tomography (SD-OCT).
Methods:
52 patients with RP (27m, 25w, age 19-74) were treated with TES (5 ms + 5 ms biphasic pulses at 20 Hz). TES was applied for 30 minutes weekly for 51 consecutive weeks with transcorneal electrodes and an OkuStim®-Device (OkuVision GmbH, Germany). SD-OCT (Spectralis®-OCT, Heidelberg Engineering GmbH, Germany) images were obtained at baseline and at eight following visits (week 10, 16, 22, 28, 34, 40, 46, and 52) in patients receiving TES (150 % (n = 15) or 200% (n = 17) of the individual electrical phosphene threshold (EPT) current at 20 Hz) or being in the sham group (n = 20) of the controlled TES study.
Results:
In 25 individuals we found small unspecific cystoid spaces. The diameter varies between 30 und 200 µm, and the area is up to 0,02 mm2. Spaces were located in the inner and outer nuclear layer of the retina. In 11 patients we found these pseudocysts in different sizes all along the study. In 14 patients they appeared and disappeared several times during the trial, in average we detected them for 6 to 12 weeks. The cystoid spaces were ascertained in 14 stimulated as well as in 24 non stimulated eyes. The appearance of these retinal changes in the study eyes was detected in 5 sham eyes, 2 eyes with 150%-TES and 7 eyes with 200%-TES. The frequency of appearance of these cystoid spaces in OCT in eyes under treatment with TES shows no statistically significant difference compared to the eyes without TES (non-treated and sham eyes; p = 0,275).
Conclusions:
To the best of our knowledge, we have collected a previously undescribed large series of SD-OCT images as part of a longitudinal study in RP patients. In these patients small cystoid spaces appeared. As they were completely independent of electrical stimulation it must be concluded that they must be considered a feature of the degenerative process in these retinas.
Keywords: 702 retinitis •
688 retina