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Vessel detection using deep-learning approaches could enable more objective measures. We aimed to evaluate vascular metrics derived from automated vessel detection and compare these metrics with manual severity gradings. Methods: Slit lamp images from 139 glaucoma patients were included. Images from 103 participants were used as the primary development dataset and the remaining as a validation subset. The images were independently graded by two graders for conjunctival hyperemia using the Efron Grading Scheme. Conjunctival vessels were detected using an automated vessel detection pipeline based on semi-supervised learning. Vessel density, fractal dimension and tortuosity were calculated and compared with the manual Efron grades. Results: Grading of conjunctival hyperemia between the two graders were consistent (Spearman\u2019s rho: 0.79; ICC: 0.79 [95%CI: 0.72\u20130.84]) but showed significant differences with a higher proportion of differences in the moderate grades. Of the vascular metrics, vessel density showed significant associations with the individual Efron grading and against the mean Efron grading (0.78, p &lt; 0.001). Fractal dimension was significantly associated with the mean Efron grading (0.55, p &lt; 0.001). Agreements were similar in the subset (vessel density, 0.80, p &lt; 0.001; fractal dimension 0.62, p &lt; 0.001). Vessel tortuosity showed lower agreements (&lt;0.23). Conclusions: Vessel density and fractal dimension showed significant associations with manual Efron gradings. These metrics could be potentially used to enable more objective and interpretable measures of conjunctival hyperemia severity.<\/jats:p>","DOI":"10.3390\/diagnostics16132066","type":"journal-article","created":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T16:50:33Z","timestamp":1782924633000},"page":"2066","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Conjunctival Vascular Metrics Using Automated Vessel Detection from Slit Lamp Images for Hyperemia Severity Assessment"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4601-9121","authenticated-orcid":false,"given":"Damon","family":"Wong","sequence":"first","affiliation":[{"name":"Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore"},{"name":"SERI-NTU Advanced Ocular Engineering (STANCE) Program, Singapore 308232, Singapore"},{"name":"Ophthalmology and Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore 169857, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yvonne","family":"Ng","sequence":"additional","affiliation":[{"name":"SERI-NTU Advanced Ocular Engineering (STANCE) Program, Singapore 308232, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9336-8941","authenticated-orcid":false,"given":"Leila Sara","family":"Eppenberger","sequence":"additional","affiliation":[{"name":"Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eduard","family":"Toma","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-2429-7936","authenticated-orcid":false,"given":"Radu","family":"Bucsan","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dan George","family":"Deleanu","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"},{"name":"Department of Ophthalmology, Emergency University Hospital, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alina Popa","family":"Cherecheanu","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania"},{"name":"Department of Ophthalmology, Emergency University Hospital, 050474 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gerhard","family":"Garh\u00f6fer","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology, Medical University of Vienna, 1090 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leopold","family":"Schmetterer","sequence":"additional","affiliation":[{"name":"Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore"},{"name":"SERI-NTU Advanced Ocular Engineering (STANCE) Program, Singapore 308232, Singapore"},{"name":"Ophthalmology and Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore 169857, Singapore"},{"name":"Department of Clinical Pharmacology, Medical University of Vienna, 1090 Vienna, Austria"},{"name":"Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore"},{"name":"School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459, Singapore"},{"name":"Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria"},{"name":"Fondation Ophtalmologique Adolphe De Rothschild, 75019 Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.jtos.2021.05.003","article-title":"Ocular redness\u2014I: Etiology, pathogenesis, and assessment of conjunctival hyperemia","volume":"21","author":"Singh","year":"2021","journal-title":"Ocul. 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