Abstract
Purpose :
Choroideremia is a currently incurable X-linked recessive retinal degenerative condition that causes blindness. Gene therapy approaches to date target the outer retinal layers. However, the choroideremia gene is expressed in all retinal layers, and a previous study on a small cohort of patients elsewhere suggested thinning of the ganglion cell layer in choroideremia. The purpose of this study was to examine that observation in more detail, using advanced imaging techniques in a larger cohort of choroideremia patients.
Methods :
Spectral domain optical coherence tomography images of the retinal nerve fibre layer (RNFL) using the Heidelberg circular scan mode were accessed retrospectively for analysis in 41 eyes of 21 choroideremia patients. As positive controls, 20 eyes from 10 patients with retinitis pigmentosa and 56 eyes from 28 normal controls were also assessed. Automated RNFL measurements were adjusted manually to precision of RNFL delineation. A normative database was used as an external control.
Results :
Mean RNFL thickness in choroideremia was 130±3µm in the right eye (RE) and 133±3µm in the LE. This was 24% and 27% thicker than RNFL thickness in controls (P<0.001 for both). Patients with retinitis pigmentosa also had an increase in RNFL thickness, which was no different to the choroideremia cohort (P>0.05). Compared with manual analysis, the automated function of the inbuilt software was consistently inaccurate in delineation of RNFL in choroideremia.
Conclusions :
The retinal nerve fibre layer is thicker in choroideremia compared with normal controls. This is similar in magnitude to that seen in retinitis pigmentosa.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.