DETERMINATION OF REFERENCE VALUES FOR INTRAOCULAR PRESSURE AND SCHIRMER TEAR TEST IN CLINICALLY NORMAL OSTRICHES (STRUTHIO CAMELUS)

Abstract

The purpose of this study was to establish normal physiologic reference values for intraocular pressure (IOP) and Schirmer tear test (STT) results in clinically normal ostriches (Struthio camelus). Twenty ostriches of both sexes, 10 juveniles (1.5-2 yr of age) and 10 adults, were included in this study. Complete ophthalmic examination was performed prior to this investigation. STT was performed by inserting a standard sterile STT strip over the ventral lid margin into the ventral conjunctival sac for 60 sec. Following the STT, IOP was measured using applanation tonometry with the Tono-Pen Vet TM tonometer after topical instillation of one drop of 0.5% proparacaine ophthalmic solution. The mean 6 SD and range of Tono-Pen readings of IOP for all birds was 18.8 6 3.5, with a range of 12-24. Mean IOP in juvenile ostriches was 19.7 6 3.6. Mean IOP in adult ostriches was 16.9 6 2.9. There was no statistically significant difference between young and adult birds (P ¼ 0.07). The mean STT values in the present study were 16.3 6 2.5 mm/1 min when measurements from both eyes were averaged. Mean STT in juvenile and adult ostriches was 15.4 6 1.8 and 17.2 6 2.9 mm/1 min, respectively. There was no statistically significant difference between young and adult birds (P ¼ 0.11). No statistically significant differences between genders were found for any of the results (P ! 0.41). In conclusion, this study provides normal reference range values for STT and IOP in clinically healthy ostriches.

Measurement of tear production and intraocular pressure in ducks and geese

“…21 No differences were found in measured IOP between genders and breeds or left or right eye in ducks and geese. Similar results were obtained in Humboldt penguins, 7 black-footed penguins, 19 ostriches, 13 American flamingos, 21 Screech owls, 10 and other birds of prey. 18 The effect of age was not assessed in this study because precise determination of age was not possible in our study population.…”

“…18 The effect of age was not assessed in this study because precise determination of age was not possible in our study population. In Humboldt penguins, 7 macaroni penguins, 8 rockhopper penguin, 8 Screech owls, 10 vultures, 12 ostriches, 13 and American flamingos, 21 the age and gender did not alter results of STT and/or IOP in studied animals. But as determined by Reuter and colleagues in some birds of prey (northern goshawks, common buzzards, and common kestrels), 18 younger birds had lower IOP values than did older birds.…”

“…15 Korbel and leiterstorper used modified Schirmer tear strips with 2-and 4-mm-wide to check lacrimal gland function of Psittaciformes (3.2 AE 2.7 to 7.5 AE 2.6 mm/min). 16 Mean AE SD tear production using 5-mm-wide Schirmer tear test strips was reported in European birds of prey (3.12 AE 1.92 to 12.47 AE 2.66 mm/ min), 11 vultures (6.4 AE 1.8 to 11.9 AE 3.3 mm/min), 12 ostrich (16.3 AE 2.5 mm/min), 13 Humboldt penguins (6.45 AE 2.9 mm/min), 7 Screech owls (2-6 mm/min), 10 bald eagles (14 AE 2 mm/min), 14 Accipitriformes (10.7 AE 4.0 to 11.5 AE 5.4 mm/min), 16 and Falconiformes (4.1 AE 2.7 to 14.4 AE 7.2 mm/min). 16 In our study, 5-mm-wide Schirmer tear test strips were placed easily in the conjunctival fornix of ducks and geese.…”

“…6 Reference ranges for intraocular pressure and tear productions have not been reported for any species in the family Anatidae. Measurement of tear production has been performed in different avian species including penguins, 7,8 owls 9,10 European birds of prey, 11 vultures, 12 ostrich, 13 bald eagles, 14 psittacine birds, 4,[15][16][17] Falconiformes, and Accipitriformes. 16 Intraocular pressure as measured by rebound tonometry has been reported in raptors, 18 20 and American flamingos (Phoenicopterusruber).…”

INTRAOCULAR PRESSURE IN SOUTHERN ROCKHOPPER (EUDYPTES CHRYSOCOME) AND MACARONI PENGUINS (EUDYPTES CHRYSOLOPHUS): EVALUATION OF INFLUENCING FACTORS

“…40 The use of rebound tonometry has also been reported in some penguin species and has shown higher mean IOP in penguins compared with reported ranges for other avian species in the current literature (Table 1). 4,6,[17][18][19]22,28,34,35,38,40,41 Numerous variables both intrinsic and extrinsic to the globe can affect IOP, including ocular inflammation or trauma, corneal pathology, corneal thickness, circadian rhythm, body and head position, restraint, sedative and anesthetic drugs, and age. 14 Two studies evaluated IOP in normal penguin eyes, but factors that may influence IOP were not investigated.…”