Cone Dystrophies: An Optical Coherence Tomography Angiography Study.

BACKGROUND

This study investigates the relationship between retinal vascularization and macular function in patients with cone dystrophies (CDs).

METHODS

Twenty CD patients (40 eyes) and 20 healthy controls (20 eyes) were enrolled in this prospective case-control study. Patients underwent full ophthalmological examination, microperimetry, full-field, pattern and multifocal electroretinogram (ERG, PERG, mfERG) and optical coherence tomography angiography (OCTA). Main outcome measures were as follows: foveal and parafoveal inner and outer retinal thickness; microperimetry sensitivity in the central 4° and 8°, ERG b wave amplitudes and peak times, PERG P50 and N95 amplitudes and latencies, and mfERG N1 to P1 amplitudes; and superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillary (CC) plexus vessel densities, divided into foveal and parafoveal region.

RESULTS

Retinal thickness, SCP and DCP densities were significantly related to PERG. A significant relationship was found between foveal and parafoveal retinal thicknesses and foveal SCP density ( < 0.001 and = 0.018, respectively) and between parafoveal retinal thickness and parafoveal SCP density ( = 0.002). Foveal and parafoveal retinal thicknesses were significantly related to parafoveal DCP density ( = 0.007 and < 0.001). Foveal and parafoveal retinal thicknesses, foveal SCP and parafoveal DPC densities were significantly reduced in CD patients compared to controls ( < 0.001; = 0.010 and = 0.008, respectively). PERG and mfERG amplitudes were significantly reduced in CD patients compared to controls ( < 0.01).

CONCLUSIONS

CD eyes showed reduced retinal thickness significantly related to reduced vessel density, possibly caused by a decreased metabolic demand. In addition, vessel density significantly correlated with loss of function.