Effect of light intensity on the tear production, central corneal thickness, and intraocular pressure in broiler chickens.

Abstract

The objective of the present study was to examine the effect of different light intensities on tear production, corneal thickness, and intraocular pressure in broilers. Both eyes of 72 male broilers were evaluated in this study. Broilers were divided into the following three groups: low light intensity (n=24, 5 lux), moderate light intensity (n=24, 20 lux), and high light intensity (n=24, 80 lux). The eyes of all birds (n=72) underwent a complete ophthalmic examination, which included the Schirmer tear test (STT-I), intraocular pressure (IOP), and the central cornea thickness measurement (CCT). The effect of light intensity on the Schirmer test, intraocular pressure, and central corneal thickness values was examined at eye and animal level (right and left eyes separately and cumulatively/no distinguishing left or right) by using one-way ANOVA. At the animal level, without discrimination of left and right eye measurements, statistically significant differences were found between 5-20 and 20-80 lux groups on IOP measurements (p < .05). The difference in CCT measurements between the 5 and 20 lux groups was statistically significant (p < .05), and the corneal thickness of the 5 lux group animals was found to be statistically significant and higher than the 20 lux group (p< .05). In conclusion, light intensity has an influence on eye health in broilers. Present results may attribute to the future studies as a reference value for broilers raised under different light intensities.