Anterior segment angiography utilising a novel spectral domain optical coherence tomography system

Session Details

Session Title: Cornea - Medical

Session Date/Time: Monday 07/09/2015 | 08:00-10:30

Paper Time: 09:45

Venue: Room 17

First Author: : S.Shahipasand UK

Co Author(s): :    D. Sim   M. Wilkins   P. Keane   C. Egan   A. Tufail   M. Ang     

Abstract Details

Purpose:

Current techniques for visualising the vasculature of the anterior segment rely on subjective imaging techniques, which may be invasive. This study evaluates a novel, non-contact optical coherence tomography (OCT) imaging system to perform advanced qualitative and quantitative analyses of the normal vascular anatomy of the cornea and anterior segment. The purpose of the study was to determine the metrics of the marginal corneal vascular arcades from 40 images obtained from 20 normal subjects (10 men, 10 women; mean age, 25.25 ± 7.87 years).

Setting:

Moorfields Eye Hospital NHS Foundation trust, UK

Methods:

We developed a method in which to acquire non-invasive angiographic images of blood vessels in the anterior segment. All scans were performed using the Avanti Angiovue spectral domain OCT (Optovue, Inc. Fremont, CA, USA) by 2 trained operators. Five contiguous squares (100 pixels, 850 micrometers) were aligned beyond the inner row of vessels extending approximately 700 micrometers into the limbal region and spanning an arc length of approximately 4 mm of the peripheral cornea. Metrics of the corneal vessels (loops, segments, segment to loop ratio and loop area) were determined using programmes written in a numerical computing environment.

Results:

We found good inter observer agreement by calculating intraclass correlation (ICC) which were 0.938 for loop number and 0.831 for segment-to-loop ratio. Statistical significance existed between nasal (2.89±0.98) and temporal images (3.57±0.99), (P< 0.001), but not between superior (3.34±1.16) and inferior (3.123±0.90) images (P=0.768) in terms of the number of loops. No significant difference was found in segment to loop ratio between superior (4.18±0.71) versus inferior (4.32±0.87) and nasal (3.94±0.69) versus temporal (4.55±0.78) with P values of 0.129 and 0.897 respectively. Vascular loop area (mm2) between superior (25.9x10-3±14.5x10-3) versus inferior (25.9x10-3±10.7x10-3) and nasal (29.7x10-3 ±15.7x10-3) versus temporal (22.1x10-3±7.1x10-3) quadrants showed no statistically significant difference (P=0.21 and 0.38 respectively).

Conclusions:

In summary, we describe a method of rapid, non-contact anterior segment angiography using a novel spectral domain OCT with good repeatability and image quality.

Financial Interest:

NONE