Optical Coherence Tomography Angiography in Myopic Patients

Evaluation of Macular Microvasculature in High Myopia Using Optical Coherence Tomography Angiography

The aim of this study is to investigate the macular microvascular network alterations in high myopic eyes using optical coherence tomography angiography.

High myopia is defined as a refractive error equal to or more than -6 D, and/or axial length equal to or more than 25.5 mm².Axial elongation of the globe and subsequent stretch of the retina leads to sight threatening complications.

Quantitative measurements of retinal vasculature in the healthy eye have been reported using several in vivo and in vitro techniques, including confocal microscopy, fluorescein angiography (FA), and swept-source optical coherence tomography (ssOCT) angiography.

The aim of this study is to investigate the macular microvascular network alterations in high myopic eyes using optical coherence tomography angiography.

This cross-sectional prospective study included 75 eyes of 54 patients, they were recruited from the outpatient clinic of ophthalmology department of El-Minia university hospital.They were divided into two groups, group A included 25 normal eyes of 25 patients. Group B included 50 myopic eyes of 30 patients.

All patients subjected to history taking and full ophthalmological examination in addition to axial length measurment before performing OCTA.

Inclusion Criteria:

• • Highly myopic subjects, defined as those with spherical equivalents (SEs) of -6 or more, with axial length greater than 26.5 mm.

Group B individuals were chosen among healthy age-matched controls.

Exclusion Criteria:

• • Patients younger than 18 years old, or older than 45 years.

  • Any patient with macular pathology (e.g. diabetic retinopathy, hypertensive retinopathy, dystrophy)
  • Myopic patients with any vitro-retinal abnormalities (e.g. choroidal neovascular membrane (CNVM), foveoschisis,macular hole)
  • Patients who underwent previous intra ocular surgical procedures.
  • Patients with previous history of intraocular injections.
  • Glaucomatous patients.

Exclusion criteria to the images that has been captured:

• - Low signal strength index (less than 50).
• - Presence of blink artefacts.
• - Poor fixation leading to motion or doubling artefacts.
• - Media opacity obscuring view of the vasculature.
• - Segmentation error due to cystoid macular oedema or epi-retinal membrane, among others.