Macropalpebral fissure
Synonym(s): Euryblepharon, Lagophthalmos
Introduction
- Cause: congenital and often associated with entropion Entropion and/or ectropion Ectropion in breeds like the St Bernard St Bernard , Bloodhound Bloodhound and Cocker Spaniel English Cocker Spaniel.
- Signs: an excessively large eyelid opening (palpebral fissure).
- Can → exposure keratitis Keratitis in brachycephalics.
- Diagnosis: clinical signs, breed.
- Treatment: surgery - permanent partial tarsorrhaphy or lid shortening techniques.
- Prognosis: good.
Presenting signs
- Exposure keratitis in brachycephalics.
- Eyelids do not close over globe.
- Exaggerated proptosis in brachycephalics.
- Combined entropion/ectropion ('diamond eye') Combined entropion / ectropion.
Age predisposition
- 6 months-3 years.
Breed/Species predisposition
- Bloodhound Bloodhound.
- Cocker Spaniel English Cocker Spaniel.
- St Bernard St Bernard.
- Brachycephalics:
- Lhasa Apso Lhasa Apso.
- Boston Terrier Boston Terrier.
- Shih Tzu Shih Tzu.
Cost considerations
- Surgical treatment, cases may require referral.
Pathogenesis
Etiology
Congenital- Overlarge palpebral fissure along with underdeveloped lateral canthal ligament → eyelid laxity.
- Exaggerated proptosis.
- Gross disparity between the size of the globe and the length of the lid.
Predisposing factors
General- Brachycephalic conformation.
Pathophysiology
Congenital- Large palpebral fissure +/- underdeveloped lateral canthal ligament → laxity of the eyelids → combined entropion/ectropion Combined entropion / ectropion.
- Large palpebral fissure plus prominent globe due to shallow orbit or gross disparity between the size of the globe and the length of the lid → lagophthalmos → exposure keratitis Keratitis.
- Exposure of eye and abnormal tear production → corneal dryness → reduced sensation of cornea and increased risk of damage.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Bedford P G (1998) Technique of lateral canthoplasty for the correction of macropalpebral fissure in the dog. JSAP 39 (3), 117-120 PubMed.
Other sources of information
- Petersen-Jones S M & Crispin S M (eds)Manual of Small Animal Ophthalmology.Cheltenham: British Small Animal Veterinary Association, 1993.