Non-invasive method of anterior segment vasculature assessment by optical coherence tomography angiography

Purpose
To present optical coherence tomography angiography as a new, non-invasive assessment method of anterior segment vasculature.

Methods
Eighteen patients (4 women, 14 men, mean age of 59.11 ± 17.83 years) with neovascularization in the anterior segment were enrolled in the study carried out between November 2016 and January 2017. All subjects were scanned with a commercially available AngioVue OCT-A system (Optovue, Inc., Fremont, CA) using an anterior segment lens adapter. Scans were taken in each quadrant of the eye with pathological vessels. Further analysis based on SSADA (Split-spectrum Amplitude-decorrelation Angiography) algorithm was carried out with internal system software.

Results
Pathological vessels in the anterior segment were visualised in each subject. The main factor affecting the quality of the scans was patient cooperation during the assessment.

Conclusions
Optical coherence tomography angiography is an effective method to visualise pathological vasculature within the anterior segment. The advantages include its non-invasiveness and acquisition speed, along with the ability to assess the depth of vessels invading the cornea. The main disadvantages to the new imaging method include technical difficulties during the assessment, small scanning area, low scanning resolution and the lack of dedicated software. However, most of these limitations will likely be eliminated by next generation devices, and optical coherence tomography angiography can become a valuable, additional examination for assessment of pathological vasculature within the anterior segment.