Effects of different monochromatic LED light colours on tear production, intraocular pressure and corneal thickness in broilers

1. This study investigated the effects of different monochromatic light-emitting diode (LED) light colours on tear production, intraocular pressure and corneal thickness in broiler chickens, and to identify any correlations among these ocular parameters.2. A total of 72 male broilers (144 eyes) were used. One-d-old chicks were randomly assigned to six experimental groups (white, blue, green, blue-green-blue, green-blue-green and white-blue-green LED light; <i>n</i> = 12). Lighting was provided using LED bulbs under identical environmental and management conditions.3. At 42 d of age, 12 birds per group were randomly selected for ophthalmological examination, including the Schirmer tear test I (STT I), intraocular pressure measurement (IOP) and central corneal thickness assessment. At the animal level, without distinguishing between right and left eyes, a significant difference was observed in central corneal thickness between birds in the white LED group and the other treatments.4. Monochromatic LED light colours affected only central corneal thickness, while tear production and intraocular pressure remained unaffected. The changes in corneal thickness observed under different light colours were within normal physiological limits, which indicated no adverse effect on ocular health in broiler chickens.