Reduced metabolic function and structural alterations in inherited retinal dystrophies: investigating the effect of peripapillary vessel oxygen saturation and vascular diameter on the retinal nerve fibre layer thickness.
OBJECTIVE
To evaluate the relationship between the peripapillary metabolic alterations [retinal vessel Oximetry (RO)] and the structural findings [retinal vessel diameter and retinal nerve fibre layer thickness (RNFL)] in patients with inherited retinal dystrophies (IRD).


METHODS
Patients with IRD [24 patients with rod-cone dystrophy (RCD), 15 patients with cone-rod dystrophy, 13 patients with inherited maculopathy] and 18 age-matched controls, who underwent RO imaging and spectral domain optical coherence tomography, were included. The average and quadrant oxygen saturation in all four major peripapillary retinal arterioles (A-SO2) and venules (V-SO2) were measured, and their difference (A-V SO2) was calculated. The corresponding retinal vessel diameter of these arterioles (D-A) and venules (D-V) was measured. The data were compared to the peripapillary RNFL thickness within the IRD subgroups and to the data obtained in the controls.


RESULTS
In general, patients with IRD had higher average V-SO2values when compared to controls (p ≤ 0.029). Rod-cone dystrophy (RCD) patients differed from controls, but also from patients with other IRDs, when the average and quadrant oxygen saturation values (A-SO2and V-SO2) were evaluated (p ≤ 0.026). Within the RCD group, the correlations of RNFL thickness to V-SO2, A-V SO2, D-A and D-V were significant (p ≤ 0.030), thus indicating a different relationship between the RNFL thickness and the examined parameters, when compared to the other groups.


CONCLUSIONS
It becomes evident from our combined metabolic-structural approach that a prediction model, to identify which individual is at risk of developing a photoreceptor degeneration of RCD type, can be proposed. It will take into account the peripapillary retinal oxygen saturation, the retinal vessel diameter and the RNFL thickness values.
Department of Ophthalmology, University of Basel, Basel, Switzerland.|McGill University, Montreal, Canada.
Rossiana I
RI
Bojinova
Department of Ophthalmology, University of Basel, Basel, Switzerland.
Cengiz
C
Türksever
Department of Ophthalmology, University of Basel, Basel, Switzerland.
Andreas
A
Schötzau
Department of Ophthalmology, Cantonal Hospital, St. Gallen, Switzerland.
Christophe
C
Valmaggia
IRO - Institute for Research in Ophthalmology, Sion, Switzerland.|Department of Ophthalmology, University of Lausanne, Lausanne, Switzerland.|School of Life Sciences, Federal Institute of Technology, Lausanne, Switzerland.
Daniel F
DF
Schorderet
Department of Ophthalmology, University of Basel, Basel, Switzerland.
Margarita G
http://orcid.org/0000-0001-8326-1449
MG
Todorova
D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology; D010092:Oximetry; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011446:Prospective Studies; D058499:Retinal Dystrophies / Q000151:congenital / Q000175:diagnosis / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012171:Retinal Vessels / Q000000981:diagnostic imaging* / Q000378:metabolism; D013997:Time Factors; D041623:Tomography, Optical Coherence
D010100:Oxygen
cone-rod dystrophy; inherited maculopathy; inherited retinal dystrophy; peripapillary retinal vessel diameter; retinal nerve fibre layer thickness; retinal vessel oxygen saturation; rod-cone dystrophy