Consideration of growth (age)-related effects on globe size and corneal thickness of ovine eyes for use in laboratory studies

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Original languageEnglish
Pages (from-to)380-384
Number of pages5
JournalClinical and Experimental Optometry
Volume100
Issue number4
Early online date3 Nov 2016
DOIs
StatePublished - Jul 2017

Abstract

PURPOSE: The aim was to assess differences in eyeball mass, corneal diameter and central corneal thickness in slaughterhouse-procured ovine eyes.
METHODS: Over a 12-year period, measurements of eye globe mass, horizontal corneal diameter and central corneal thickness were routinely undertaken within two hours post-mortem. Only eyes free of obvious mechanical damage or disease were used.
RESULTS: From measurements on 736 quality-selected and trimmed eyes, globe wet mass ranged from 10.4 to 25.2 g, horizontal corneal diameter from 19.0 to 26.5 mm and central corneal thickness measured by ultrasonic pachymetry from 0.543 to 0.836 mm (with an overall average of 690 ± 0.056 mm). The ocular globe mass was strongly correlated to horizontal corneal diameter (r 2 ¿=¿0.829). Central corneal thickness correlated with globe mass (r¿=¿0.543) and to horizontal corneal diameter (r¿=¿0.402). Based on the different anatomical measurements, a lamb's eye would be expected to have a thinner cornea (average 0.640¿mm) than that of an adult outbred ewe (average 0.730¿mm). In freshly procured eyes showing signs of slight corneal oedema, central corneal thickness was greater (average 0.856¿±¿0.052¿mm) and up to 24 hours of cold storage resulted in predictable increases in central corneal thickness of six to 24 per cent, especially in eyes showing signs of corneal oedema before storage.
CONCLUSIONS: Based on the correlations obtained, differences in ovine eyes can be attributed to growth-related differences in the animals and thus, indirectly to their expected ages. A simple measure of the horizontal corneal diameter in ovine eyes used for laboratory studies would be a useful indicator in reporting these studies.

Keywords

  • corneal thickness, optometry