Effect of alfentanil on the blood flow of rabbit eye

The selective u agonist, alfentanil [10 ug/kg i.v.], increased the blood flow in albino rabbits, to the ocular tissues [iris root, ciliary body, retina, and choroid] through its respiratory depressant effect. The depressant effect of alfentanil, and the subsequent increase in ocular tissue blood flow were blocked by pretreating animals with the K agonist/u antagonist, nalbuphine [0.6 mg/kg i.v.], which alone has no effect on ocular blood flow. These results might indicate that the use of the narcotic analgesic alfentanil has a potential for use in patients with insufficient retinal blood flow undergoing ophthalmic or general surgery

Glaucoma a clinico-experimental study of the effect of interaction of some anti-glaucoma drugs on the intraocular pressure

Many drugs are used in the management of glaucoma, each exerting its effect through a certain mechanism. The interaction of two or more of these drugs administered concomittently is of importance to the ophthalmologist. Such interaction may reduce the intraocular pressure [IOP], or may antagonize the intended therapeutic effect of any of them. The effect of pilocarpine, timolol, eserine and diamox, each alone and in different combinations was studied clinically in 149 eyes of chronic simple glaucoma, and experimentally in albino rabbits. The results showed that pilocarpine remains the most effective and safest topical drug for prolonged use in open angle glaucoma. The use of timolol is accompanied by two phenomena "the short term escape" and the "long term drift". Combining it with another drug after one year of its use is essential to keep its efficiency. Pilocarpine-acetazolamide is the most effective combination in reducing IOP compared to all other combinations

effect of pyrrolizidine alkaloid heliotrine on the structures of the eye of rabbits

The work was carried out to study the effect of pyrrolizidine alkaloids on the structures of the eye. A dose of 40 mg/kg heliotrine HCL was injected intravenously in ten rabbits which were sacrificed after two weeks. Sections were prepared from enucleated eyeballs for light microscopic study.Histopathological changes were observed particularly in the vascular coat of the eye in the form of dilatation and congestion of the blood vessels of the iris, ciliary body, choroid and retina. Neovascularization of the retina and hyalinosis of the choroidal blood vessels were observed and edema in the nerve fiber layer of the retina was noted. These changes might seem innocent but considering the ability of progression of the lesions impairment of ocular function could result in the form of rise in intraocular pressure, choroidal atrophy and infarction and vitreous hemorrhage