{
  "abstract": "Background\n\nTo compare corneal epithelial thickness (CET) profiles among different types of regular astigmatism and early keratoconus (KCN) using the MS-39 anterior segment optical coherence tomography (AS-OCT) and to identify disease-specific epithelial asymmetry patterns, regional epithelial thickness, and ROC performance.Methods\n\nThis comparative cross-sectional study included 96 eyes from 55 participants: with-the-rule astigmatism (WTR, n = 34), against-the-rule astigmatism (ATR, n = 19), oblique astigmatism (OBL, n = 13), and early keratoconus (KCN, n = 30). Corneal epithelial thickness maps and central corneal thickness (CCT) were obtained with the MS-39 AS-OCT. Because some participants contributed both eyes and group sizes were unequal, eye-level comparisons used participant-clustered robust standard errors. Multivariable models additionally adjusted for age, sex, cylinder power, and CCT. ROC 95% confidence intervals were estimated by participant-level cluster bootstrap.Results\n\nRegular astigmatic eyes showed the expected superior-to-inferior epithelial thickness gradient, whereas early KCN eyes showed relative superior epithelial thickening and attenuation of this gradient. CCT was lower in early KCN than in regular astigmatism (499.9 ± 29.3 μm vs. 555.7 ± 39.5 μm; P < 0.001). After adjustment for age, sex, cylinder power, and CCT, superior epithelial thickness remained greater in early KCN in the 2-5 mm annulus (adjusted B = + 2.78 μm; 95% CI, 1.15 to 4.41; P < 0.001) and 5-7 mm annulus (B = + 3.17 μm; 95% CI, 1.30 to 5.04; P < 0.001). The superior-inferior difference in the 2-5 mm zone also remained attenuated (B = + 2.10 μm; 95% CI, 0.51 to 3.68; P = 0.010). Superior ET at 2-5 mm had an AUC of 0.75 (95% CI, 0.62-0.87); a combined epithelial model yielded an AUC of 0.79 (95% CI, 0.67-0.90).Conclusions\n\nEarly KCN showed region-specific epithelial thickness differences characterized by relative superior epithelial thickening and attenuation of the normal vertical epithelial gradient. These differences persisted after adjustment for overall CCT, suggesting that the principal findings were not explained solely by differences in total corneal thickness. Diagnostic performance was moderate, so epithelial mapping should be considered an adjunct to established tomographic assessment.",
  "abstract_shown": true,
  "affiliations": [
    "Eye Research Center, Five Senses Institute, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.",
    "Department of Ophthalmology, School of Medicine, Urmia University of Medical Science, Urmia, Iran. paryaabdolalizadeh@gmail.com.",
    "Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran.",
    "Bina Eye Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Yasaman Hadi",
      "orcid": "0000-0001-8332-2950"
    },
    {
      "affs": [
        0
      ],
      "name": "Farideh Kheimeh Kabood"
    },
    {
      "affs": [
        1
      ],
      "name": "Parya Abdolalizadeh",
      "orcid": "0000-0002-7420-7448"
    },
    {
      "affs": [
        0
      ],
      "name": "Leila Ghiasian",
      "orcid": "0000-0002-0692-4488"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Marjan Mazouchi",
      "orcid": "0000-0002-3048-0258"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5he3ej6rk9zwj.bib",
  "cited_by": 0,
  "doi": "10.1186/s12886-026-05412-5",
  "fulltext_url": "https://europepmc.org/articles/PMC13651415",
  "id": "5he3ej6rk9zwj",
  "issns": [
    "1471-2415"
  ],
  "landing_url": "https://europepmc.org/article/MED/42850600",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2741|Corneal surgery and disorders"
    ]
  ],
  "openalex": "W7221012886",
  "pdf_url": "https://europepmc.org/articles/PMC13651415?pdf=render",
  "pmcid": "PMC13651415",
  "pmid": "42850600",
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5he3ej6rk9zwj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:02Z",
      "native_id": "MED:42850600",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42850600"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2741|Corneal surgery and disorders",
      "subfield": "imaging"
    }
  ],
  "title": "Regional corneal epithelial thickness and asymmetry patterns in early keratoconus versus regular astigmatism using MS-39 anterior segment OCT: a comparative cross-sectional study.",
  "title_text": "Regional corneal epithelial thickness and asymmetry patterns in early keratoconus versus regular astigmatism using MS-39 anterior segment OCT: a comparative cross-sectional study.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:02Z",
  "url": "https://research.draconitic.com/paper/5he3ej6rk9zwj",
  "venue": "BMC ophthalmology",
  "versions": []
}