Purchase this article with an account.
Muhammad Hassaan Ali, Juan Pablo Davila Gonzalez, Federico Velez, Andrea Estefania Diaz, David Sarraf, Stacy L. Pineles; QUANTITATIVE ASSESSMENT OF NORMAL IRIS VASCULAR DENSITY USING ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2883. doi: https://doi.org/.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Optical coherence tomography angiography (OCTA) is a novel, non-invasive technique that has recently been used to evaluate vascular changes seen in iris, retina and choroidal capillaries in different ocular conditions like amblyopia, tumors, and diabetes. A normative database of quantitative analysis of normal iris vascular density does not exist due to a lack of appropriate commercial software for iris analysis. We conducted this cross-sectional observational study to analyze normal iris vasculature and quantitatively assess normal iris vascular density using OCTA.
We imaged irides of 8 eyes of healthy participants using Optovue RTVue XR 100 Avanti Spectral Domain-OCTA (Optovue Inc., Fremont, CA) using an anterior segment lens. Due to the lack of dedicated iris analyzing software, the retina split spectrum amplitude decorrelation angiography (SSADA) algorithm was used to analyze normal irides but was manually modified for focusing of the irides in different layers and vascular planes. Iris images were taken in 3 x 3 and 6 x 6 millimeter cubes, reconstructed in three dimension and overall iris vascular density calculated in nasal, superior, inferior and temporal quadrants.
The mean age of the participants was 56.2 ± 20.3 (range: 32 – 83) years. Interpretable good quality OCTA signals were best recorded in light colored irides than darker ones, the latter requiring instillation of 1% pilocarpine drops. OCTA grossly showed iris architecture with radially oriented arteries located in superficial and veins in deeper planes in iris stroma. Maximal vascular projections were seen at the level of posterior iris pigment epithelium. The mean iris vascular density was found to be 58.9 ± 7.9, 56.7 ± 7.0, 54.4 ± 10.3 and 46.7 ± 8.8 % in the inferior, nasal, superior and temporal iris sectors respectively. The variations in age and gender of the subjects did not significantly affect normal iris vascular density (p-value > 0.05).
This pilot clinical study showed that OCTA can be used to objectively and quantitatively study the anatomic structure and vascular density of irides. Larger studies are needed to establish normative database of iris vascular density that can help in subsequent non-invasive detection of pathological iris vascular changes in various ocular conditions like anterior segment ischemia, iris tumors, ischemic retinopathies and glaucoma.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
This PDF is available to Subscribers Only