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Veterinary ophthalmology2026; 29(5); e70243; doi: 10.1111/vop.70243

Complications Following Nictitating Membrane Resection in Horses: 92 Eyes (2015-2024).

Abstract: The goal of this retrospective study is to evaluate the complications following nictitating membrane resection in horses with the aim of providing valuable information on the risks of this surgical procedure. Methods: 83 horses (92 eyes). Methods: Medical records for 83 horses that underwent nictitating membrane resection in 92 eyes between February 2015 and June 2024 were reviewed. Horses were included if they had at least 1 month of follow-up data available. Owners were contacted via telephone or email questionnaire to obtain follow-up information. Complications were recorded only when present in the surgical eye and not in the contralateral eye. Owner-reported findings were included only when they were persistent at the time of follow-up or noted beyond the immediate postoperative period (> 1 week). Results: The overall owner reported complication rate was 28.2% (26/92). Complications that occurred within 1 week of surgery were fat prolapse (n = 4; 4.3%) and hemorrhage (n = 1; 1.1%). Long-term complications noted by owners included epiphora (n = 21; 22.8%) and conjunctivitis (n = 9; 9.8%). The incidence of fat prolapse was low, with no cases reported when sutures were placed (p = 0.80). There were follow-up examinations performed for 39 horses and 23.1% had complications. These included epiphora (n = 4; 10.3%), conjunctival adhesion (n = 1; 2.6%), fat prolapse (n = 2; 5.1%), and enophthalmos (n = 2; 5.1%). Conclusions: Overall complications reported by owners and found on examination were minor and easily managed. Chronic mild epiphora is the most common complication that persists after the nictitating membrane resection procedure and should be reviewed with owners.
© 2026 The Author(s). Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.
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Publication Date: 2026-08-06 PubMed ID: 42559850DOI: 10.1111/vop.70243Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study retrospectively analyzed complications following surgical removal of the nictitating membrane (third eyelid) in horses to assess the risks associated with the procedure.
  • The research involved reviewing medical records and owner reports for 83 horses (92 eyes) treated between 2015 and 2024.

Study Purpose and Methods

  • Objective: To evaluate complications after nictitating membrane resection surgeries in horses to inform veterinary care and owner expectations.
  • Data source: Medical records from 83 horses that underwent surgery on 92 eyes from February 2015 to June 2024.
  • Inclusion: Horses with at least 1 month of postoperative follow-up data.
  • Follow-up: Obtained through owner questionnaires (phone or email) and clinical examinations when available.
  • Complication criteria: Only recorded if present in the operated eye and not in the opposite, non-operated eye; owner-reported issues included only if persistent beyond 1 week post-surgery.

Key Findings – Complication Rates and Types

  • Overall complications reported by owners occurred in 28.2% of eyes (26 out of 92).
  • Early (within 1 week) complications included:
    • Fat prolapse in 4 cases (4.3%)
    • Hemorrhage in 1 case (1.1%)
  • Long-term complications noted by owners included:
    • Epiphora (excessive tearing) in 21 cases (22.8%) — the most common long-term complication
    • Conjunctivitis (inflammation of the conjunctiva) in 9 cases (9.8%)
  • Impact of suture placement: Fat prolapse was rare and no cases were reported when sutures were placed during surgery, although this was not statistically significant (p = 0.80).

Follow-up Clinical Examinations

  • Follow-up examinations were available for 39 horses; 23.1% showed complications on examination.
  • Observed complications included:
    • Epiphora in 4 horses (10.3%)
    • Conjunctival adhesion (scar tissue) in 1 horse (2.6%)
    • Fat prolapse in 2 horses (5.1%)
    • Enophthalmos (sunken eye appearance) in 2 horses (5.1%)

Conclusions and Clinical Implications

  • Complications following nictitating membrane resection in horses are generally minor and manageable.
  • The most common long-term issue is mild chronic epiphora, which should be discussed with horse owners before surgery to set realistic expectations.
  • Early complications like fat prolapse and hemorrhage are infrequent and do not significantly impact overall patient outcomes when managed appropriately.
  • The study provides veterinarians and horse owners with practical information on risks, aiding in surgical decision-making and postoperative care planning.

Cite This Article

APA
Wu T, Stefanovski D, Scherrer NM. (2026). Complications Following Nictitating Membrane Resection in Horses: 92 Eyes (2015-2024). Vet Ophthalmol, 29(5), e70243. https://doi.org/10.1111/vop.70243

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 29
Issue: 5
Pages: e70243

Researcher Affiliations

Wu, Tiantian
  • Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA.
Stefanovski, Darko
  • Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA.
Scherrer, Nicole M
  • Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA.

MeSH Terms

  • Animals
  • Horses
  • Nictitating Membrane / surgery
  • Horse Diseases / surgery
  • Retrospective Studies
  • Postoperative Complications / veterinary
  • Female
  • Male
  • Eye Diseases / veterinary
  • Ophthalmologic Surgical Procedures / veterinary
  • Ophthalmologic Surgical Procedures / adverse effects

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