Electroretinogram Changes in the Crew of the 12-month Isolation Experiment SIRIUS-23

The international experiment SIRIUS-23 studied the effect of long-term isolation in a closed space (hermetic object — artificial station), simulating an interplanetary flight with accompanying stress factors, on the bioelectrical activity of the retina. The aim of the study was to evaluate changes in the different types of electroretinogram (ERG), and in visual evoked cortical potentials (VEP) in the participants of the 12-month experiment. Changes in ocular blood flow were also assessed using Doppler research Methods. All diagnostic examinations were conducted before and during the week after the crew exited isolation (conditional “landing”). The results indicate the general stability of the most studied parameters after the end of isolation. A slight decrease in the amplitude of flicker ERG (F-ERG) to 30 and 12 Hz flickers and P50 and N95 components of transient pattern ERG (PERG) with characteristic changes in peak latency was revealed, which indicate a mild dysfunction of retinal ganglion cells and their axons without organic damage to the visual pathways. A positive trend towards an increase in the amplitude of the photopic negative response (PhNR) to a medium-strength stimulus and the amplitude of the P100 component of VEP to a pattern-reversal to a pattern-reversal chessboard stimuli after the crew exited isolation was found. A statistically significant increase in the peripheral resistance index and pulsatility index in the ophthalmic artery, central retinal artery and lateral posterior short ciliary arteries was recorded, which may indicate a change in vascular tone in the retinal and choroidal circulation system of the eye after a 12-month experiment.