Morphofunctional state of the retina in pilots according to the results of optical coherence tomography

Introduction. For the first time, researchers performed optical coherence tomography with retinal angiography (OCTA) in pilots, and they also performed a correlation analysis of OCTA results with the pilot's age and flight load.

The study aims to research the condition of the retina based on the results of OCTA in the studied group of pilots in correlation with age and flight load.

Materials and methods. The main group of the study consisted of 120 pilots in the age range of 24–45 years, whose total flight time ranged from 52 to 1600 hours. The authors divided this group into 2 subgroups depending on the flight load (no more than 60 hours per year and more than 60 hours per year). The control group consisted of 79 men aged 24 to 45 years, whose professional activity is not associated with extreme types of work. To analyze the morphometric state of retinal ganglion cells, scientists divided the main and control groups into 3 age subgroups (24–30, 31–35, 35–45 years). The results of OCTA were evaluated based on the results of examination of each eye. The scientists have performed morphological structural analysis of the areas of the central, paracentral retina and optic disc using the OCTA protocols "ONH", "RNFL", "3D Disk" and "GCC". The state of the blood supply to the retina was assessed according to the OCTA protocols "ND Angio Retina", "HD Angio Disk 4.4", "Fovea Density". The authors have conducted a statistical analysis using StatTech software version 3.1.8 (developed by Stattech LLC, Russia). "Statistics 10".

The comparison of the two quantitative groups with a normal distribution, provided that the variances were equal, was carried out using the Student's t-test, and with unequal variances, using the Welch t-test.

The comparison of the two groups by a quantitative indicator, the distribution of which differed from the normal one, was performed using the Mann-Whitney U-test.

Results. The analysis of optical coherence tomography of the retina in pilots for the first time revealed morphometric destruction (the presence of acquired increased curvature of retinal vessels, areas of reduced blood supply, local destruction of pigment epithelium, the presence of areas of retinal disorganization (DRIL)) in a certain percentage of cases, which was not related to flight load or age. These changes in pilots can be both a consequence of chronic stress and the result of hypoxia during flight.

The analysis of the blood flow status of the central and paracentral retinal zones revealed a statistically significant decrease in blood flow levels according to the indicator: Fovea VD (Vessel Density) in 70% of the pilots, where increased vascular tortuosity was diagnosed compared with the control group (p>0.001).

An analysis of the morphometric status of retinal ganglion cells in pilots based on the results of the evaluation of the OKTA "GCC" protocol revealed a significant difference in the GLV% indicator (global ganglion cell losses) compared with the control group.

Limitations. The study has professional (pilots) and gender (men) limitations. Persons with ophthalmological pathology and with an ametropia of more than 3.0 diopters are also excluded.

Conclusion. The changes in the morphofunctional state of the retina in pilots revealed by the results of optical coherence tomography reflect the individual characteristics of adaptation to extreme factors of flight load.

Morphological destructions of the retina, such as the presence of acquired increased curvature of retinal vessels, areas of reduced blood supply, local destruction of the pigment epithelium, and the presence of areas of retinal disorganization (DRIL) may indicate a decrease in the activity of autoregulatory adaptation mechanisms both at the retinal and central nervous system levels. An increase in the OCTA index (GLV%) in pilots in the age group of 25–30 years may indicate a decrease in the functional activity of the central nervous system due to stress response factors.

Ethics. The study was conducted in compliance with Ethical principles. All subjects signed a voluntary informed consent to participate in the study in accordance with the Helsinki Declaration of the World Medical Association "Ethical Principles of conducting scientific medical research involving humans as subjects." The study was approved by the local Ethics Committee of the N.N. Burdenko State Medical University (Protocol No. 262 dated 04/26/2022).

Contributions:
Podyanov D.A. — concept and design of research, collection and processing of material, final editing;
Gracheva M.A. — collection and processing of material, statistical data processing, text editing;
Kazakova A.A. — collection and processing of material;
Osetsky N.Y. — collection and processing of material, statistical data processing;
Koneva D.A. — collection and processing of material, statistical data processing;
Fomin A.V. — collection and processing of material;
Manko O.M. — research concept and design, material processing, text writing, editing.

Funding. The funding was provided as part of a research project (R&D RAS FVFR-2024-0034 (1023022700092-0-3.1.4.; 1.9; 5.1.1)).

Conflict of interest. The authors declare no conflict of interest.

Received: 01.11.2025 / Accepted: 14.11.2025 / Published: 20.12.2025

1. Ushakov I.B., Shalimov P.M. Functional reliability and functional reserves of the pilot. Vestnik Rossijskoj akademii medicinskih nauk. 1996; 7: 26–31. https://elibrary.ru/zhfimr

2. Timme E.A., Bubeev Ju.A., Pisarev A.A. Monitoring and forecasting of the functional state of military specialists in conditions of mountain training. Voenno-medicinskij zhurnal. 2009; 330(1): 13. https://elibrary.ru/stkvyr

3. Kolosov S.V. Issues of information and psychological readiness of flight personnel to perform their intended tasks. Novaja nauka: Ot idei k rezul'tatu. 2016; 1–3: 51–55. https://elibrary.ru/xbtqxr

4. Buhtijarov I.V., Denisov Je.I., Lagutina G.N., Pfaf V.F., Chesalin P.V., Stepanjan I.V. Criteria and algorithms for establishing a relationship between health disorders and work. Med. truda i prom. ekol. 2018; (8): 4–12. https://doi.org/10.31089/1026-9428-2018-8-4-12

5. Smirnova N.N., Solov'ev A.G., Korehova M.V., Novikova I.A. Professional stress and stress tolerance of specialists in extreme activities: A textbook. Arhangel'sk: Severnyj gosudarstvennyj medicinskij universitet; 2017. https://elibrary.ru/zutkcn

6. Suhanova G.A., Serebrov V.Ju. Cell Biochemistry. Tomsk: Charodej; 2000. https://elibrary.ru/vjeubt

7. Gao X.M., Chen X., Cui G.Yu. et al. Mechanism of blood-brain barrier damage and progress in its treatment after ischemic stroke. Cell Biosci. 2023; 13: 196. https://doi.org/10.1186/s13578-023-01126-z

8. David J. Bonda, Xinglong Wang, George Perry, Akihiko Nunomura, Massimo Tabaton, Xiongwei Zhu, Mark A. Smith. Oxidative stress in Alzheimer disease: A possibility for prevention. Neuropharmacology. 2010; 59(4–5): 290–294. https://doi.org/10.1016/j.neuropharm.2010.04.005

9. Lamirel C., Newman N.J., Biousse V. Optical coherence tomography (OCT) in optic neuritis and multiple sclerosis. Revue neurologique. 2010; 166(12): 978–986. https://doi.org/10.1016/j.neurol.2010.03.024

10. Fuglo D., Kallenbach K., Tsakir A., et al. Retinal atrophy correlates with MRI response in patients with recovered optic neuritis. Neurology. 2011; 77(7): 645–651. https://doi.org/10.1212/WNL.0b013e3182299e36

11. Capper E.N., Linton E.F., Anders J.J. et al. MOG35−55-induced EAE model of optic nerve inflammation compared to MS, MOGAD and NMOSD related subtypes of human optic neuritis. J. Neuroinflammation. 2025; 22(1): 102. https://doi.org/10.1186/s12974-025-03424-4

12. Gordon-Lipkin E., Chodkowski B., Reich D.S., Smith S.A., Pulicken M., Balcer L.J., Frohman E.M. et al. Retinal nerve fiber layer is associated with brain atrophy in multiple sclerosis. Neurology. 2007; 69(16): 1603–1609. https://doi.org/10.1212/01.wnl.0000295995.46586.ae

13. Abdallah M., Hunter A., Al-Diri B. Quantifying retinal blood vessel tortuosity — a review. In: 2015 Science and Information (SAI) Conference. London: IEEE: 2015: 687–693. https://doi.org/10.1109/SAI.2015.7237216

14. Moss H.E. Vascular changes in the retina are a marker of cerebrovascular diseases. Curr. Neurol. Neurosci. Rep. 2015; 15(7): 40. https://doi.org/10.1007/s11910-015-0561-1

15. Zenkov N.K., Lankin V.Z., Men'shhikova E.B. Oxidative stress: biochemical and pathophysiological aspects. Moskva: MAIK "Nauka/Interperiodika"; 2001. https://elibrary.ru/ruqssz

16. Kravchuk E.A. The role of free radical oxidation in the pathogenesis of eye diseases. Vestnik oftal'mologii. 2004; 120 (5): 48–51. https://elibrary.ru/tunyzn

17. Mironova Je.M. Retinal pigment epithelium: structure, functions, role in the pathogenesis of eye diseases. Glaz. 2005; 41(1): 4–8.

18. Onishi A.S., Ashraf M., Soetikno B.T., Fauzi A.A. Multilevel ischemia in disorganization of the inner retinal layers according to projection-resolved optical coherence tomography angiography. Retina. 2019; 39(8): 1588–1594. https://doi.org/10.1097/IAE.0000000000002179

19. Sun J.K., Radwan S.H., Soliman A.Z., et al. Neural retinal disorganization as a robust marker of visual acuity in current and resolved diabetic macular edema. Diabetes. 2015; 64(7): 2560–2570. https://doi.org/10.2337/db14-0782

20. Rzaeva N.M., Dmitrenko A.I. The visual cortex and its involvement in the regulation of retinal function. Vestnik oftal'mologii. 2013; 129(1): 4–9. https://elibrary.ru/pxzqwn