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Veterinary ophthalmology2019; 23(1); 4-15; doi: 10.1111/vop.12677

Laser scanning in vivo confocal microscopic characterization of equine immune-mediated keratitis.

Abstract: To describe the corneal in vivo confocal microscopy (IVCM) findings in horses with putative immune-mediated keratitis (IMMK). Methods: Sixty five horses with IMMK. Methods: Horses diagnosed with IMMK were examined with a modified Heidelberg Retina Tomograph II and Rostock Cornea Module. The findings from the IVCM examinations were correlated with clinical details from ophthalmic examination and diagnostic test results. Results: Eighty eyes from 65 horses were examined. Clinical IMMK lesions were categorized as epithelial (n = 17 eyes), superficial stromal (n = 38), midstromal (n = 18), and endothelial (n = 7). Epithelial, superficial stromal, and midstromal lesions were characterized with IVCM by variable corneal leukocyte infiltrates and vascularization of the approximate corneal anatomic region that was clinically affected as determined by biomicroscopy. In addition, all horses displayed a dense network of dendritic cells in the epithelial basement membrane and immediate subepithelial stroma. Less consistent IVCM findings included epithelial disorganization, corneal edema, mineral deposition, stromal fibrosis, and epithelial pigment granules. Endothelial IMMK was distinct from the other forms of IMMK and characterized with IVCM by stromal edema, endothelium disorganization, endothelial cell loss, and multifocal accumulations of highly reflective material within the endothelium. Conclusions: The distinguishing feature of epithelial and stromal forms of IMMK is a dense accumulation of dendritic cells in the epithelial basement membrane and immediate subepithelial stroma. Cellular changes in endothelial IMMK were largely confined to the endothelium and distinct from the other forms of IMMK evaluated.
Publication Date: 2019-05-02 PubMed ID: 31050168DOI: 10.1111/vop.12677Google Scholar: Lookup
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  • Journal Article

Summary

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This research discusses using in vivo confocal microscopy (IVCM), a non-invasive imaging technique, to study and describe the corneal changes observed in horses diagnosed with immune-mediated keratitis (IMMK). Features within different layers of cornea were identified and correlated with clinical conditions seen in horses and this can provide better accuracy in diagnosis and treatment of the condition.

Objective and Methodology

  • The aim of the study was to investigate the cellular changes occurring in horse corneas affected by putative immune-mediated keratitis, a group of corneal diseases, using in vivo confocal microscopy (IVCM). This technique allows for non-invasive, real-time imaging of the living corneal tissue.
  • The study involved 65 horses diagnosed with IMMK, and 80 eyes were examined in total. The IVCM was performed using a modified Heidelberg Retina Tomograph II and Rostock Cornea Module.
  • The findings were then correlated with the clinical details extracted from ophthalmic examinations and diagnostic test results.

Results

  • Based on the clinical presence of IMMK lesions, they were classified into 4 categories: epithelial (17 eyes), superficial stromal (38 eyes), midstromal (18 eyes), and endothelial (7 eyes).
  • The IVCM identified diverse corneal leukocyte infiltrates and vascularization in the affected corneal areas. These changes were spotted in the epithelial, superficial stromal and midstromal lesions.
  • All horses showed dense networks of dendritic cells in their epithelial basement membrane and immediate subepithelial stroma, irrespective of the type of lesions.
  • Other less consistent changes observed included epithelial disorganization, corneal edema, mineral deposition, stromal fibrosis, and epithelial pigment granules.
  • Endothelial IMMK differed significantly from other types. It was characterized by stromal edema, disorganised endothelium, endothelial cell loss, and accumulations of highly reflective material within the endothelium.

Conclusions

  • The dense accumulation of dendritic cells in the epithelial basement and immediate subepithelial stroma areas was identified as a characteristic feature of epithelial and stromal forms of IMMK.
  • Cellular alterations in endothelial IMMK were primarily confined to the endothelium and were distinct from the other forms of IMMK evaluated in this study.

Significance of the Study

  • This study provides valuable insights into the cellular changes occurring in the corneas of horses suffering from IMMK and could aid in the diagnosis and treatment of this condition in future.
  • The results demonstrate the effectiveness of IVCM as a tool for non-invasive and precise examination of corneal conditions in horses.

Cite This Article

APA
Ledbetter EC, Irby NL. (2019). Laser scanning in vivo confocal microscopic characterization of equine immune-mediated keratitis. Vet Ophthalmol, 23(1), 4-15. https://doi.org/10.1111/vop.12677

Publication

ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 23
Issue: 1
Pages: 4-15

Researcher Affiliations

Ledbetter, Eric C
  • Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York.
Irby, Nita L
  • Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York.

MeSH Terms

  • Animals
  • Eye / pathology
  • Female
  • Horse Diseases / pathology
  • Horses
  • Keratitis / immunology
  • Keratitis / pathology
  • Keratitis / veterinary
  • Male
  • Microscopy, Confocal

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Citations

This article has been cited 3 times.
  1. Padjasek M, Cisło-Sankowska A, Lis-Bartos A, Qasem B, Marycz K. PLDLA/TPU Matrix Enriched with Cyclosporine A as a Therapeutic Platform for Immune-Mediated Keratitis (IMMK) in Horses. Int J Mol Sci 2023 Mar 17;24(6).
    doi: 10.3390/ijms24065735pubmed: 36982806google scholar: lookup
  2. Mayes MA, Casanova MI, Park S, Steele K, Linton L, Kim S, Good KL, Moore BA, Newbold GM, Leonard BC, Li JY, Thomasy SM. Canine endotheliitis: Clinical characteristics, advanced imaging features, and treatment. Vet Ophthalmol 2022 May;25 Suppl 1(Suppl 1):185-192.
    doi: 10.1111/vop.12967pubmed: 34971485google scholar: lookup
  3. Preston JF, Mustikka MP, Priestnall SL, Dunkel B, Fischer MC. Clinical features and outcomes of horses presenting with presumed equine immune mediated keratitis to two veterinary hospitals in the United Kingdom and Finland: 94 cases (2009-2021). Equine Vet J 2025 May;57(3):598-610.
    doi: 10.1111/evj.14213pubmed: 39183684google scholar: lookup