Quantitative analysis of conjunctival microvasculature imaged using optical coherence tomography angiography

Area of Science:

• Ophthalmology
• Medical Imaging
• Microcirculation Research

Background:

• Assessing bulbar conjunctival microvascular density is crucial for ocular health.
• Traditional methods may lack quantitative precision.
• Optical coherence tomography angiography (OCTA) offers a novel approach.

Purpose of the Study:

• To quantitatively analyze bulbar conjunctival microvascular density using OCTA.
• To compare OCTA findings with vessel density measurements from functional slit-lamp biomicroscopy (FSLB).

Main Methods:

• Temporal bulbar conjunctiva of 20 eyes from 10 healthy subjects were imaged.
• Both OCTA and FSLB techniques were employed for imaging.
• Image processing involved equalization, de-noising, thresholding, and skeletonization.
• Vessel density was quantified using fractal analysis (Dbox) and pixel counting (%).

Main Results:

• OCTA yielded significantly lower bulbar conjunctival vessel density (Dbox: 1.28 ± 0.01; %: 3.31 ± 0.12) compared to FSLB (Dbox: 1.32 ± 0.01; %: 3.69 ± 0.16).
• No significant correlations were found between OCTA and FSLB measurements for either Dbox or percentage vessel density.
• Strong correlations existed between Dbox and percentage vessel density within each respective instrument (OCTA: r=0.98; FSLB: r=1.0).

Conclusions:

• Bulbar conjunctival microvascular density can be quantitatively assessed using OCTA.
• OCTA measurements of conjunctival vessel density are not directly comparable to those obtained via FSLB.
• Further research is needed to reconcile discrepancies between OCTA and FSLB in microvascular density assessment.