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Association of height, body weight, age, and corneal diameter with calculated intraocular lens strength of adult horses

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  • 1 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 2 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 3 Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Abstract

Objective—To determine whether differences exist in the calculated intraocular lens (IOL) strengths of a population of adult horses and to assess the association between calculated IOL strength and horse height, body weight, and age, and between calculated IOL strength and corneal diameter.

Animals—28 clinically normal adult horses (56 eyes).

Procedures—Axial globe lengths and anterior chamber depths were measured ultrasonographically. Corneal curvatures were determined with a modified photokeratometer and brightness-mode ultrasonographic images. Data were used in the Binkhorst equation to calculate the predicted IOL strength for each eye. The calculated IOL strengths were compared with a repeated-measures ANOVA. Corneal curvature values (photokeratometer vs brightness-mode ultrasonographic images) were compared with a paired t test. Coefficients of determination were used to measure associations.

Results—Calculated IOL strengths (range, 15.4 to 30.1 diopters) differed significantly among horses. There was a significant difference in the corneal curvatures as determined via the 2 methods. Weak associations were found between calculated IOL strength and horse height and between calculated IOL strength and vertical corneal diameter.

Conclusions and Clinical Relevance—Calculated IOL strength differed significantly among horses. Because only weak associations were detected between calculated IOL strength and horse height and vertical corneal diameter, these factors would not serve as reliable indicators for selection of the IOL strength for a specific horse.

Contributor Notes

Supported by Accutome.

Presented in abstract form at the 42nd Annual Meeting of the American College of Veterinary Ophthalmologists, Hilton Head, SC, October 2011.

Address correspondence to Dr. Townsend (townsenw@purdue.edu).