Reduced vessel density in deep capillary plexus correlates with retinal layer thickness in choroideremia

Area of Science:

• Ophthalmology
• Medical Imaging
• Genetics

Background:

• Choroideremia (CHM) is a rare X-linked genetic disorder.
• CHM leads to progressive vision loss due to degeneration of the retinal pigment epithelium (RPE) and photoreceptors.
• Understanding retinal layer changes and vascular alterations in CHM is crucial for disease management.

Purpose of the Study:

• To assess retinal layer thickness in patients with choroideremia (CHM).
• To investigate the correlation between optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) findings in CHM.
• To analyze vessel density (VD) changes in superficial capillary (SCP), deep capillary (DCP), and choriocapillaris (CC) plexuses.

Main Methods:

• Observational, cross-sectional clinical study involving 14 CHM eyes and 14 age-matched controls.
• Multimodal imaging using OCT and OCTA to analyze retinal layers and vascular networks.
• Separate analysis of apparently preserved retinal islets and atrophic regions.

Main Results:

• Significant thinning observed in ganglion cell layer (GCL), outer nuclear layer (ONL), ellipsoid zone-retinal pigment epithelium (EZ-RPE), and choroid in CHM eyes, especially in atrophic areas.
• Inner retinal layers (INL, IPL) were thinned in both preserved and atrophic regions; outer plexiform layer (OPL) was unaffected in preserved areas.
• Deep capillary plexus (DCP) was severely affected in both regions, while choriocapillaris (CC) was altered only in atrophic regions; significant correlations between OCT and OCTA parameters were found.

Conclusions:

• CHM causes severe alterations in both outer and inner retinal layers.
• The extensive retinal involvement may result from reduced neuronal and vascular trophic factors due to RPE dysfunction.
• Secondary Müller glial cell reactions may also contribute to the observed retinal changes in CHM.