Orhan Elibol

The effect of povidone iodine on the corneal endothelium.

Purpose. Povidone iodine has been proven to be a valuable antiseptic solution in preparing the eye for surgery and is an alternative to postoperative topical antibiotics. No study has addressed the intraocular toxicity of povidone iodine after injection into the anterior chamber. We investigated the potential toxicity of povidone iodine on the corneal endothelium after injections into the anterior chamber in a rabbit model. Methods. In this study we used 24 eyes of 12 albino rabbits. The eyes were divided into the following three groups according to the drugs tested: group A, 5% povidone iodine; group B, 10% povidone iodine; group C, balanced salt solution. The injected eyes were evaluated by biomicroscopy, specular microscopy, corneal pachymetry, and transmission and scanning electron microscopy. Results. Corneal edema was observed in all eyes of groups A and B. In groups A and C, the endothelial cell morphology was not significantly changed and the mean endothelial cell count of the eyes did not change significantly (p = 0.5054). There was no significant difference in corneal thickness between groups A and C (p = 0.3823), but there was a significant difference between groups B and C (p = 0.0002). Transmission and scanning electron microscopy results were normal in group C but not in groups A and B. Conclusion. Povidone iodine in both 5% and 10% concentrations demonstrates severe toxicity when one drop of either concentration is placed directly in the anterior chamber. When povidone iodine is used in preparing the eye for intraocular surgery and as an alternative to postoperative antibiotics, the inadvertent leakage of povidone iodine into the anterior chamber must definitely be prevented.

Apraclonidine and clonidine: a comparison of efficacy and side effects in normal and ocular hypertensive volunteers

We performed a prospective, randomized double blind study comparing the cardiovascular and intraocular pressure (IOP) effects of unilateral therapy with clonidine 0.125% and apraclonidine hydrochloride 1.0% in 15 normal and 15 ocular hypertensive volunteers. Baseline values were obtained prior to instillation. One drop of test medication (clonidine, apraclonidine or placebo) was instilled unilaterally, and the postinstillation measurements were taken at 1, 2, 4, 6 and 8 hours. Apraclonidine 1% produced a maximum 31.4%±6.9% (4.83±1.17mmHg) decrease in mean IOP in ocular normotensive volunteers and 33.9%±6.9% (10.10±2.45 mmHg) in ocular hypertensive patients (p<0.001).These values were 22.1%±6.9% (2.90±1.94 mmHg) and 22.7%±6.9 (6.80±2.31 mmHg), respectively in clonidine group (p<0.001).In apraclonidine group, there were no changes in contralateral IOP, blood pressure or pulse rate. Clonidine produced a significant decrease in contralateral IOP, but this reduction was not statistically significantly different than that of placebo. In clonidine group, there was no change in pulse rate, but a significant decrease in blood pressure.Eyelid retraction, conjunctival blanching and mydriasis were noted in eyes treated with apraclonidine. However there were no statistically and clinically significant changes in pupil size or interpalpebral fissure width with clonidine.This study suggests that apraclonidine appears to be safer and more effective ocular hypotensive agent than clonidine in treatment of glaucoma.

Penetrating corneal fish-hook injury.

A healthy 13-year-old female was struck in the left eye by a fish-hook while fishing. The fish-hook penetrated the cornea, passed the anterior chamber and exited from a second corneal site near the limbus. The fish-hook was removed by cutting its shank and pushing it out of the wounds. Visual acuity was 20/20 OS after surgery. Mild corneal scarring was present at the penetration sites. We would like to report this case because there is a limited number of patients with penetrating corneal fish-hook injuries and this case presents the only female patient in the ophthalmological literature who suffered corneal fish-hook injury.

The effects of dopamine, haloperidol and bromocriptine on intraocular pressure.

In a double-blind randomised, prospective single dose study, we measured intraocular pressure (IOP), pupil diameter, systemic blood pressure and heart rate in 43 ocular normotensive subjects before (baseline) and 2, 4, and 6 hours after topical instillation of the following drugs: dopamine 2% (n=11), a dopamine receptor blocking drug, haloperidol 0.5% (n=11), a dopamine receptor stimulating drug, bromocriptine 0.05% (n=11) and 0.1% (n=10).In the groups receiving dopamine or haloperidol, there were no significant differences in IOP compared with baseline values (p>0.01). But, a significant decrease in IOP compared with the baseline values was found in both bromocriptine groups (p<0.001). With the 0.05% and 0.1% concentrations, maximum reductions in intraocular pressure were 22.0%±5.8% and 28.4%±9.8%, respectively.No significant differences in mean pupil diameter, systemic blood pressure and heart rate were detected in all of these groups.In addition, in the group receiving bromocriptine 0.1%, there was no change in serum prolactin levels.These results suggest that topically administered bromocriptine has satisfactory intraocular pressure lowering capacity without serious ocular or systemic side effects. Consequently we conclude that, an ophthalmic formulation of bromocriptine may have substantial clinical potential for the treatment of glaucoma.

The determination of additive effect and intraocular pressure lowering effects of 0.05% bromocriptine and 0.25% timolol

It has been confirmed that topically applied bromocriptine has a satisfactory intraocular pressure (IOP) lowering effect without serious ocular or systemic side effects. We compared the IOP lowering effects of 0.05% bromocriptine and 0.25% timolol and determined whether they have an additive effect in lowering IOP in normal volunteers.In a double-blind, randomised, prospective, single-dose study, we measured IOP in 24 ocular normotensive subjects before (baseline) and 2, 4 and 6 hours after topical instillation of the following drugs: timolol and bromocriptine alone (n : 14), timolol + bromocriptine, timolol + placebo, bromocriptine + placebo (n : 10).Both bromocriptine and timolol have a significant IOP lowering effect (p < 0.01) compared with the baseline value during the study period. There were no significant differences in IOP lowering effect between timolol and bromocriptine at 2 and 4 hours (p > 0.05), but timolol was more efficacious than bromocriptine at 6 hours (p < 0.05). An additive effect in lowering IOP was not found.Although timolol and bromocriptine have no additive effect in lowering IOP, topically applied bromocriptine may be used in the treatment of glaucoma.