Preliminary findings of the ophthalmologic exam of owls
Eugenia Bermúdez-Jiménez, Randall Arguedas
Costa Rica has 17 owl species recorded and the Simon Bolivar Zoo holds seven of these species that came from different reasons including trauma and orphaned individuals. Around 54% of the incoming cases are related to general trauma and pupillary light responses to different light frequency may help the initial diagnosis when head trauma is suspected. After a cranioencephalic trauma event, ocular inflammation can lead to secondary ocular hypertension that, if left untreated, can cause blindness. Thirty-seven individuals from seven species: Ciccaba virgata (n=8), Ciccaba nigrolineata (n=2), Pseudoscops clamator (n=6),, Megascops choliba (n=7) and Glaucidium brasilianum (n=5),Pulsatrix perspicillata (n=3) and Tyto alba (n=6) were examined. The evaluation was performed in the morning, using tetracaine ophthalmic drops, slit lamp, applanation tonometry (Tonopen), blue and red light source and the panoptic. The ophthalmic evaluation consisted of checking the anterior segment, posterior segment, light responses and finally intraocular pressure was measured. The mean and standard deviation of intraocular pressure per species were: C. virgata (12.07 ± 1.67), C. nigrolineata (12.0 ± 0), P. clamator (10.46 ± 1.66), , M. choliba (12.42 ± 1.60), G. brasilianum (11.66 ± 1.73), P. perspicillata (11.50 ± 2.81) and T. alba (14.41 ± 0.79). Only two owls had apparent elevated intraocular pressure (18 and 20 respectively). The light response was fast and similar on all the species except the C. virgata that reacts slower to the red light. C. virgata individuals must have further analysis like ERG (electroretinogram) to investigate possible anatomical or physiological mechanisms that might explain the apparently slow light response within the rods on the retina that can be causing some blindness.