Ahead of print

Original article

Optical Coherence Tomography Angiography Findings in Patients with New-Onset Type 2 Diabetes and No Signs of Diabetic Retinopathy

Bahadır Özelbaykal
Fikret Ünal

Full Text links

Keywords: new-onset type 2 diabetes; foveal avascular zone; optical coherence tomography angiography; inner retinal layer; outer retinal layer

Summary

Aim: This study aims to assess and compare by means of optical coherence tomography angiography (OCTA) early modifications in the retinal layer of new-onset type 2 diabetic patients without clinical signs of diabetic retinopathy (NDR).

Materials and Methods: A total of 51 NDR patients and 53 normal individuals’ retinal capillary foveal density, superficial and deep capillary plexus, foveal avascular zone area (FAZ) parameters were evaluated with OCTA. Inner retinal layer (IRL) thickness and outer nuclear layer thickness (ONL) at the temporal and nasal margin of FAZ were measured in 26 NDR and 26 healthy subjects, using ImageJ 1.46r software.

Results: Vascular density in the superficial and deep whole image (SWIVD and DWIVD) was significantly lower in patients than in controls for right eyes (RE) and left eyes (LE), (RE SWIVD: p < 0.001, LE SWIVD: p = 0.004, RE DWIVD: p < 0.001, LE DWIVD: p = 0.028). There was no significant difference in the values of the FAZ area in the right and left eye between patient and control groups (RE: p = 0,652; LE: p = 0.509). No significant difference was found in the T/N IRL thickness between study and control groups (p = 0.552, p = 0.094, respectively). The AUC analysis for vascular densities ranged from 0.625 to 0.751.

Conclusion: Our study found that the density of blood vessels decreases before clinical signs of retinopathy appear in newly diagnosed type 2 diabetic patients.

References

  1. International Diabetes Federation. IDF Diabetes Atlas. 10th. Brussels, Belgium: International Diabetes Federation 2021.p.2.
  2. Yau JW, Rogers SL, Kawasaki R, et al. Meta-Analysis for Eye Disease (META-EYE) Study Group. Global prevalence and major risk factors of diabetic retinopathy. Diabetes Care. 2012;35(3):556-564.
  3. Das A, Mc Guire PG, Rangasmay S. Diabetic macular edema: pathophysiology and novel therapeutic targets. Ophthalmology. 2015;122(7):1375-1394.
  4. de Carlo TE, Chin AT, Bonini Filho MA, et al. Detection of microvascular changes in eyes of patients with diabetes but not clinical diabetic retinopathy using optical coherence tomography angiography. Retina. 2015;35(11):2364-2370.
  5. Dimitrova G, Chihara E, Takahashi H, Amano H, Okazaki. Quantitative retinal optical coherence tomography angiography in patients with diabetes without diabetic retinopathy. Invest Ophthalmol Vis Sci. 2017;58(1):190-196.
  6. Simonett JM, Scarinci F, Picconi F, et al. Early microvascular retinal changes in optical coherence tomography angiography in patients with type 1 diabetes mellitus. Acta Ophthalmol. 2017;95(8):751-755.
  7. Cao D, Yang D, Huang Z, et al. Optical coherence tomography angiography discerns preclinical diabetic retinopathy in eyes of patients with type 2 diabetes without clinical diabetic retinopathy. Acta Diabetol. 2018;55(5):469-477.
  8. Zhang B, Chou Y, Zhao X, Yang J, Chen Y. Early detection of microvascular impairments with optical coherence tomography angiography in diabetic patients without clinical retinopathy: a meta-analysis. Am J Ophthalmol. 2021; 222:226-237.
  9. Hogg RE, Wright DM, Dolz-Marco R, et al. Quantitative parameters from OCT angiography in patients with diabetic retinopathy and in those with only peripheral retinopathy compared with control participants. Ophthalmol Sci. 2021;1(2):100030.
  10. Palochak cmA, Lee HE, Song J, et al. Retinal blood velocity and flow in early diabetes and diabetic Retinopathy using adaptive optics scanning laser ophthalmoscopy. J Clin Med 2019;8(8):1165.
  11. Rask-Madsen C, King GL. Vascular complication of diabetes: mechanisms of injury and protective factors. Cell Metab. 2013;17(1):20- 33.
  12. Dai Y, Zhou H, Chu Z, et al. Microvascular changes in the choriocapillaris of diabetic patients without retinopathy investigated by swept-source OCT angiography. Invest Ophthalmol Vis Sci. 2020;61(3):50.
  13. Goudot mm, Sikorav A, Semoun O, et al. Parafoveal OCT angiography features in diabetic patients without clinical diabetic retinopathy: a qualitative and quantitative analysis. J Ophthalmol. 2017;14.
  14. Lee D-H, Yi HC, Bae SH, Cho JH, Choi SW, Kim H. Risk Factors for Retinal microvascular impairment in type 2 diabetic patients without diabetic retinopathy. PLoS ONE. 2018;13(8): 0202103.
  15. Temel E, Demirel S, Batıoğlu F, Özmert E. Association between optical coherence tomography angiography findings and inner retinal thickness in diabetic patients. Turk J Ophthalmol. 2022;52(5):331-
  16. Cuk J, Stanisavljevic D, Vasilijevic J, et al. Predictive vascular changes in OCTA in diabetic patients. Biomedicines. 2025;13(6):1486.
  17. Isaac DLC, Pires ACF, Neves LL, et al. Effect of disease duration on foveal microvasculature assessed by OCTA in type 2 diabetes mellitus without clinical diabetic retinopathy. Int J Retina Vitreous. 2025;11:66.
  18. Kim K, Kim ES, Yu SY. Optical coherence tomography angiography analysis of foveal microvascular changes and inner retinal layer thinning in patients with diabetes. Br J Ophthalmol. 2018;102(9):1226-1231.
  19. Torres-Villaros H, Timoumi R, Fajnkuchen F, Klokner A, Giocanti-Auregan A. Macular thickness fluctuations and visual acuity outcomes after intravitreal dexamethasone implant for diabetic macular edema. Retina. 2024;44(11):1937-1944.
  20. Wei Q, Wang W, Qiu Q. Central macular thickness and foveal avascular zone are indicators of early diabetic retinopathy. Clin Ophthalmol. 2025;19:3505-3514.
  21. Murugesan S, Jha KN, Krishnagopal S, Ezhumalai G. Central Macular Thickness in Diabetics without Retinopathy. TNOA J Ophthalmic Sci Res. 2018;56(3):150-154.
  22. Shah J, Tan B, Wong D, et al. Evaluation of thickness of individual macular retinal layers in diabetic eyes from optical coherence tomography. Sci Rep. 2024;14:17909.
  23. Demir M, Oba E, Dirim B, Ozdal E, Can E. Central macular thickness in patients with type 2 diabetes mellitus without clinical retinopathy. BMC Ophthalmol. 2013;9;13:11.
  24. Chui TYP, Van Nasdale DA, Elsner AE, Burns SA. The Association between the foveal avascular zone and retinal thickness. Invest Ophthalmol Vis Sci. 2014;55(10):6870-6877.
  25. Shiihara H, Terasaki H, Sonoda S, et al. Objective evaluation of size and shape of superficial foveal avascular zone in normal subjects by optical coherence tomography angiography. Sci Rep. 2018;8(1):10143.
  26. Arthur E, Papay JA, Haggerty BP, Clark CA, Elsner AE. Subtle changes in diabetic retinas localised in 3D using OCT. Ophthalmic Physiol Opt. 2018;38(5):477-491.
  27. Kaizu Y, Nakao S, Arima M, et al. Flow density in optical coherence tomography angiography is useful for retinopathy diagnosis in diabetic patients. Sci Rep. 2019;9:8668.