Abstract 

IMMEDIATE EFFECTS OF DIAMOND BURR DEBRIDEMENT IN PATIENTS WITH SPONTANEOUS CHRONIC CORNEAL EPITHELIAL DEFECTS; LIGHT AND ELECTRONMICROSCOPIC EVALUATION

C DAWSON1, C NARANJO2,3, N ESCANILLA1, G FRICKER4, DJ GOULD4, C KAFARNIK4, R LINN-PEARL4, RF SANCHEZ1, B SANCHEZ-MALDONADO2, M MATAS-RIERA1

1 Ophthalmology Service, Royal Veterinary College, University of London.
2 Departamento de Medicina y Cirugía Animal, Universidad Complutense de Madrid, Madrid, Spain 
3 Ocular Pathology Specialists, Madrid, Spain 
4 Davies Veterinary Specialists, Manor Farm Business Park, Higham Gobion, Herts

Purpose: To evaluate immediate effects of diamond burr debridement (DBD) on the cornea of canine patients diagnosed with spontaneous chronic corneal epithelial defects (SCCEDs). Methods: Nine eyes from eight client-owned dogs with SCCEDs underwent superficial keratectomy (SK). The ulcerated area was divided into four quadrants with restricted depth knife. Two of four quadrants underwent DBD for 40-60 seconds. A SK followed. One burred and one non-burred section were fixed with formaldehyde 10% and underwent light microscopy (LM). The remaining quadrants were fixed with glutaraldehyde 2.5% and underwent transmission electron microscopy (TEM). The pathologists were masked to the samples. Student’s paired t-tests were used to analyse the data. This study was approved by the Royal Veterinary College Ethics Committee (URN 2013 1234). Results: With LM all non-burred samples had a superficial stromal hyaline acellular zone (HAZ), seven of the burred samples had an intermittent HAZ and in two burred samples this zone was absent. The HAZ thickness of burred samples (1.062 ± 0.664µm) was significantly thinner than that of the non-burred samples (4.309 ± 1.348 µm) (P<0.0001). TEM showed an absence of basement membrane and the presence of an amorphous, fine fibrillar material in the superficial stroma in non-burred samples. This material was intermittent or absent in burred samples. Conclusion: DBD significantly reduces the superficial stromal HAZ in SCCEDs, which is believed to interfere with the healing of these defects. Support: Alger Company provided financial support in the form of a grant to fund the evaluation of histopathology samples.