The mydriatic effect of 3 curare-like neuromuscular blocking agents was tested in European kestrels (Falco tinnunculus) after topical application. Alcuronium chloride (5 mg/ml) was found to be effective at a dose of 1 drop (20 drops = 1 ml) administered twice at a 15-minute interval. Mydriasis was achieved at t = 26 +/- 11 minutes, maximal effect was reached at t = 60 +/- 39 minutes, and sufficient mydriasis ended at t = 364 +/- 134 minutes. Nevertheless, side effects, including temporary full paralysis in 1 bird, indicated that this drug should not be used. Pancuronium bromide (2 mg/ml) had an inconsistent effect on each bird at a dose of 2 drops administered twice at 15-minute intervals, and total mydriasis was not reached in 5 of 8 birds. Mydriasis was achieved at t = 34 +/- 11 minutes, maximal effect was reduced and reached at t = 43 +/- 13 minutes, and sufficient mydriasis ended at t = 90 +/- 39 minutes. Vecuronium bromide (4 mg/ml) was administered at a dose of 2 drops, 3 times, at 15-minute intervals. Mydriasis was achieved at t = 23 +/- 8 minutes, maximal effect was reached at t = 65 +/- 12 minutes, and sufficient mydriasis ended at t = 253 +/- 65 minutes. Side effects were not detected. Vecuronium bromide should be used in raptorial birds whenever retinal examination requires fundoscopy.

Topically administered tissue plasminogen activator (tPA) was evaluated for its penetration into aqueous humor of clinically normal dogs. Two concentrations of tPA (5 mg/ml and 10 mg/ml) were evaluated in a single-dose study, and a concentration of 5 mg of tPA/ml was used for a multiple-dose study. The contralateral eye served as a nontreated control. Enzyme substrate analysis of aqueous humor was used to determine tPA activity. The activity of tPA in aqueous humor was significantly (P < 0.05) greater in treated eyes of all dogs, compared with that in control eyes. Significant differences in activity of tPA were not detected at different doses in treated eyes.

The association between ocular squamous cell tumors and various measures of solar radiation was evaluated for 2,775 contemporaneous Hereford cattle. The animals were from 34 herds located in 21 states in the United States and in one Canadian province. Examinations and photographs were made of the eyes of all cows and heifers in a herd; 33 herds were examined between June and August 1957 and 1 herd was examined in 1958. Solar radiation was measured by altitude and mean annual hours of sunshine applying to an individual herd, and global radiation, a cloudiness index, and elevation of nearby National Weather Service stations. All measures of solar radiation provided evidence of a significant association between increasing risks of developing cancer eye and increasing levels of radiation; adjustments were made for possible confounding effects of age and corneoscleral pigmentation. Associations were evident whether affliction was defined as the occurrence of any type of tumor (ie, plaque, papilloma, or carcinoma), or as the occurrence of only papilloma or carcinoma. Average ages of affected cattle also tended to be lower at high radiation levels than at low levels, further supporting the hypothesis that solar radiation has an important role in the development of this disease. In view of the heritability of eye pigmentation and its inhibitory effect on lesions, cancer eye may be controlled by selective breeding for increased pigmentation in and around the eye to afford protection against the harmful effects of incident UV radiation.

An experimental model of keratoconjunctivitis sicca (KCS) was produced by removing the lacrimal gland and the gland of the third eyelid from the left eye of 6 cats. The right eye of each cat was left intact and used as a control. After 2 weeks, cats were euthanatized and the central portion of the upper eyelid from both eyes of each cat was excised. Histologic sections were stained with either hematoxylin and eosin or with a battery of biotinylated lectins including concanavalin A (conA), soybean agglutinin (SBA), wheat germ agglutinin (WGA), succinylated wheat germ agglutinin (S-WGA), Ulex europaeus agglutinin I (UEA), Dolichos biflorus agglutinin (DBA), Ricinus communis agglutinin (RCA), peanut agglutinin (PNA), and PNA pretreated with neuraminidase. Consistent differences in histologic features were not observed between conjunctivas with KCS and control conjunctivas. A variable degree of mononuclear cell infiltration of the substantia propria was observed in control conjunctivas and those with KCS. In both groups, conjunctival goblet cell density decreased and epithelial stratification increased as the degree of submucosal inflammatory cell infiltration increased. Lectin binding sites for DBA, WGA, S-WGA, UEA, PNA, and PNA pretreated with neuraminidase were detected on conjunctival goblet cells of conjunctivas with KCS and control conjunctivas. The mucus/glycocalyx layer of conjunctival epithelial cells in both groups of conjunctivas bound lectins RCA, WGA, UEA, and conA, but inconsistently bound S-WGA. In both groups, DBA principally bound to the mucus layer overlying normal epithelium, whereas PNA pretreated with neuraminidase consistently bound to the mucus layer of stratified epithelial surfaces free of goblet cells. Binding of SBA to goblet cells and the mucus/glycocalyx layer was variable.

The effect that topical administration of cyclosporine would have on the number and type of microorganisms isolated from the corneal surface of dogs with keratoconjunctivitis sicca was studied. Schirmer tear tests were performed on and corneal swab specimens were collected from 61 eyes of 31 dogs with keratoconjunctivitis sicca prior to and after 3, 6, and 12 months of treatment with cyclosporine. In eyes that responded to cyclosporine treatment (Schirmer tear test value increased by greater than or equal to 5 mm/min, compared with pretreatment value), the percentage of eyes from which bacteria were isolated after 3, 6, and 12 months of treatment was significantly (P < 0.001) less than the percentage from which bacteria were isolated prior to treatment. However, among eyes that did not respond to treatment, we did not detect a significant change over time in prevalence of bacteria or type of bacteria isolated. The percentage of eyes from which fungi were isolated decreased during treatment; however, the small number of eyes in which fungal culture results were initially positive precluded demonstration of a significant change. For all eyes, we did not detect any significant differences over time in the frequency with which specific bacterial genera were isolated, with the exception of beta-hemolytic Streptococcus spp. Opportunistic corneal infections were not detected even though none of the dogs received antibiotics. An increase in production of tears, which contain anti-infection proteins, was believed to be the primary factor responsible for the decrease in the percentage of eyes from which microorganisms could be isolated.

Uveitis was induced in dogs by intracameral injection of canine lens protein. The lipoxygenase inhibitors phenidone and norhydroguaiaretic acid, and dimethyl sulfoxide decreased fibrin production at 0.5 and 1 hour after induction uveitis. Phenidone and norhydroguaiaretic acid also inhibited the initial increase intraocular pressure early in the course of inflammation. Leukotriene B4 in the aqueous was measured by use of radioimmunoassay at 1 hour after inflammation. In control dogs, 230 to 1,700 pg of leukotriene B4/ml was measured; in dogs treated with phenidone, leukotriene, B4 was not measured.

Intraocular pressure (IOP) was measured by use of Mackay-Marg applanation tonometry in 8 normal, manometrically controlled, enucleated, canine eyes with and without 1 of 2 piano therapeutic soft contact lenses (1 and 2) covering the cornea. Differences were not significant between measurements made without a contact lens and those made through either lens at manometer IOP < 30 mm of Hg. At manometer IOP greater than or equal to 30 mm of Hg, use of a contact lens tended to result in a statistically greater (P < 0.05) estimate of IOP than when a lens was not used. This difference, however, achieved only a maximum of 2.6 mm of Hg at the 80 mm of Hg value, and was not regarded as clinically important. Measurements obtained through lens 1 were not significantly different from those obtained through lens 2. The IOP can be accurately estimated in dogs; using the Mackay-Marg tonometer, without removing either type of bandage soft contact lens, thereby avoiding potential disruption of an already compromised cornea.