Tear production, intraocular pressure, and central corneal thickness in white-tailed deer (Odocoileus virginianus).

Abstract

To evaluate the tear production, intraocular pressure, and central corneal thickness in healthy white-tailed deer (Odocoileus virginianus) and assess for seasonal variability. Nineteen healthy fawns (3-10days old) and 8 healthy adult white-tailed deer (164-280days old) were studied. All fawns were manually restrained for the study, while adult animals were immobilized with an intramuscular injection of combined xylazine (2.2mg/kg), tiletamine (1mg/kg), and zolazepam (1mg/kg). Tear production (STT-1) was evaluated in both eyes of all fawns. Intraocular pressure (applanation and rebound tonometry) and central corneal thickness (ultrasound pachymetry) were determined in both eyes of all fawns and adult deer. Mean±SD tear production in fawns was 12.32±4.46mm/min. Mean±SD IOP values in the fawns were 16.21±4.97mmHg (TonoPen® ) and 14.05±5.03mmHg (TonoVet® ). In adult deer, mean±SD IOP values were 15.57±2.88mmHg with TonoPen® and 12.87±2.57 with TonoVet® , and TonoPen® significantly overestimated the IOP, compared to TonoVet® (P<0.005). The IOP was not significantly different between young and adult animals (P=0.22). A significant difference (P<0.005) in CCT values was observed between fawns (528.42±27.65μm) and adult deer (747.55±41.60μm). This study reports normal values of tear production in healthy fawns, and intraocular pressure and central corneal thickness in healthy young and adult white-tailed deer.