Quantitative Analysis of Ocular Microcirculation Images in Human Health and Disease

The vascularized ocular tissues are conjunctiva which covers the outer layer of the eye and the retina which is located in the back of the eye. Conjunctival microvascular hemodynamic alterations due to systemic and vascular diseases have been reported. However, previous qualitative or semi-automated methods were limited for quantifying hemodynamics in a large number of vessels within the microvascular network. Due to the high physiological variability and vessel density, there is a need for an automated image processing technique for quantitative and comprehensive assessment of hemodynamics in the conjunctival microvascular network. Additionally, assessment of alterations in the conjunctival and the retinal vascular pattern provides a means for computerized disease diagnosis and discrimination. Techniques have been developed for discriminating systemic and ocular diseases using retinal vascular images. Nevertheless, a method for discriminating stages of disease based on conjunctival microvascular images has not been reported previously. Finally, increased retinal vessel tortuosity is known to be among early indicators of various retinopathies. However, previous techniques for quantitative assessment of retinal vessel tortuosity are limited in that their findings are not always consistent with the visual perception of tortuosity or might be scale dependent. Therefore, the goal in this research study was to develop and apply image processing techniques for detection of hemodynamic, vascular pattern, and morphological alterations due to systemic and vision-threatening diseases.