Consider sources of bias when using OCT angiography
October 15, 2023

Consider sources of bias when using OCT angiography

The Science behind the Tip

OCT angiography (OCTA) has gained great interest in glaucoma diagnosis (1, 2) and follow up(3). However, several condiBons and diseases can impact its results and should be considered, especially when performing longitudinal analyses(4). The following systemic diseases have been idenBfied as potenBal sources of bias (even when no visible fundus changes exist): arterial hypertension, Diabetes Mellitus, coronary artery disease, caroBd artery stenosis, chronic kidney disease (as well as being under haemodialysis), obstrucBve sleep apnea syndrome, and several neurodegeneraBve diseases, such as Alzheimer’s Disease, mulBple sclerosis and Parkinson’s Disease(5). Overall, these diseases led to reduced vessel density (VD) and an increased foveal avascular zone (FAZ) area and perimeter. Other condiBons, such as performing regular high-intensity interval exercise (VD decrease) or being pregnant (VD increase) can also impact the results. Many of the published studies on this topic did not perform adjustment for relevant confounders and this should be improved in future studies.

Contributor: João Barbosa Breda MD PhD FEBOS, Porto, Portugal


  1. Van Melkebeke L, Barbosa-Breda J, Huygens M, Stalmans I. OpBcal Coherence Tomography Angiography in Glaucoma: A Review. Ophthalmic Res. 2018:1-13.
  2. Miguel AIM, Silva AB, Azevedo LF. DiagnosBc performance of opBcal coherence tomography angiography in glaucoma: a systemaBc review and meta-analysis. The BriBsh journal of ophthalmology. 2019;103(11):1677-84.
  3. Miguel A, Silva A, Barbosa-Breda J, Azevedo L, Abdulrahman A, Hereth E, et al. OCTangiography detects longitudinal microvascular changes in glaucoma: a systemaBc review. The BriBsh journal of ophthalmology. 2022;106(5):667-75.
  4. Monteiro-Henriques I, Rocha-Sousa A, Barbosa-Breda J. OpBcal coherence tomography angiography changes in cardiovascular systemic diseases and risk factors: A Review. Acta ophthalmologica. 2022;100(1):e1-e15.
  5. Tsokolas G, Tsaousis KT, Diakonis VF, Matsou A, Tyradellis S. OpBcal Coherence Tomography Angiography in NeurodegeneraBve Diseases: A Review. Eye Brain. 2020;12:73- 87.

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