Quantitative analysis of conjunctival vascular alterations: Applications in ocular and systemic disease detection

The conjunctival blood vessels are the only microcirculatory system on the body surface that can be observed non-invasively. Anatomically interconnected with multiple craniofacial circulatory systems, these vessels can indirectly reflect the blood supply to these areas and the overall state of systemic microcirculation. We synthesize findings from 48 studies spanning 2020-2025. Overall, existing research has found that the conjunctival vascular parameters can change in various diseases such as diabetes, cardiovascular diseases, and autoimmune diseases, and may even precede organic lesions. Recent advancements in conjunctival vessel imaging and analysis technologies have enabled the identification and evaluation of various ocular and systemic diseases based on conjunctival vascular parameters. However, existing studies are limited by insufficient sample sizes, covariate interference, limited disease types, a lack of investigation into the underlying mechanisms of conjunctival vascular changes, and inadequate integration with emerging technologies, such as artificial intelligence. Future research should aim to broaden the scope of investigation, delve deeper into the mechanisms governing conjunctival vascular alterations, and integrate artificial intelligence to establish a solid foundation for the clinical application of conjunctival vascular parameters.