Transscleral Coulomb-controlled iontophoresis of methylprednisolone into the rabbit eye: influence of duration of treatment, current intensity and drug concentration on ocular tissue and fluid levels.

The major problems associated with the use of corticosteroids for the treatment of ocular diseases are their poor intraocular penetration to the posterior segment when administered locally and their secondary side effects when given systemically. To circumvent these problems more efficient methods and techniques of local delivery are being developed. The purposes of this study were: (1) to investigate the pharmacokinetics of intraocular penetration of hemisuccinate methyl prednisolone (HMP) after its delivery using the transscleral Coulomb controlled iontophoresis (CCI) system applied to the eye or after intravenous (i.v.) injection in the rabbit, (2) to test the safety of the CCI system for the treated eyes and (3) to compare the pharmacokinetic profiles of HMP intraocular distribution after CCI delivery to i.v. injection. For each parameter evaluated, six rabbit eyes were used. For the CCI system, two concentrations of HMP (62.5 and 150mg ml(-1)), various intensities of current and duration of treatment were analyzed. In rabbits serving as controls the HMP was infused in the CCI device but without applied electric current. For the i.v. delivery, HMP at 10mg kg(-1)as a 62.5mg ml(-1)solution was used. The rabbits were observed clinically for evidence of ocular toxicity. At various time points after the administration of drug, rabbits were killed and intraocular fluids and tissues were sampled for methylprednisolone (MP) concentrations by high pressure liquid chromatography (HPLC). Histology examinations were performed on six eyes of each group. Among groups that received CCI, the concentrations of MP increased in all ocular tissues and fluids in relation to the intensities of current used (0.4, 1.0 and 2.0mA/0.5cm(2)) and its duration (4 and 10min). Sustained and highest levels of MP were achieved in the choroid and the retina of rabbit eyes treated with the highest current and 10min duration of CCI. No clinical toxicity or histological lesions were observed following CCI. Negligible amounts of MP were found in ocular tissues in the CCI control group without application of current. Compared to i.v. administration, CCI achieved higher and more sustained tissue concentrations with negligible systemic absorption. These data demonstrate that high levels of MP can be safely achieved in intraocular tissues and fluids of the rabbit eye, using CCI. With this system, intraocular tissues levels of MP are higher than those achieved after i.v. injection. Furthermore, if needed, the drug levels achieved with CCI can be modulated as a function of current intensity and duration of treatment. CCI could therefore be used as an alternative method for the delivery of high levels of MP to the intraocular tissues of both the anterior and posterior segments.

Methylprednisolone concentrations in the vitreous and the serum after pulse therapy.

PURPOSE: Intravenous (i.v.) pulse of corticosteroids has been used to treat severe eye inflammation from different origins. Whether such large doses result in vitreous levels that differ either in magnitude or duration from more conventional corticotherapy remain unsolved issues. The authors therefore determined levels of methylprednisolone hemisuccinate and methylprednisolone in the vitreous and serum of patients at different times after a single i.v. perfusion of methylprednisolone hemisuccinate. METHODS: Fifty patients scheduled for a first vitrectomy received an i.v. injection of 500 mg hemisuccinate methylprednisolone at different times before surgery (from 15-24 hours). Patients were divided into two groups: those with (n = 21) and without (n = 29) retinal detachment (RD). Pure vitreous samples were analyzed by high-pressure liquid chromatography. RESULTS: Both the ester and the nonester methylprednisolone forms were sampled in the vitreous, showing a slower rate of hydrolysis compared to the serum. On average, the highest concentration of total methylprednisolone in the vitreous was found at 2.5 hours and rapidly decreased for the group of patients with RD. In the group of patients without RD, the highest concentration was reached at 6 hours and then slowly decreased. The antiinflammatory potency in the nondetached retina eyes was approximately 500 times more than in the physiologic vitreous, but despite the route of administration (i.v. or oral), only 1/10 of the corticosteroid serum concentration was measured in the vitreous. CONCLUSION: High concentration of methylprednisolone is achieved by i.v. pulse therapy without changing the kinetic of entry in the vitreous of nondetached retina eyes when compared to conventional oral corticotherapy. Hydrolysis occurs in the vitreous resulting in high rate of active form. Pulse therapy could be considered in cases of severe ocular inflammation involving the posterior segment of the eye.

[Reis-Buckler dystrophy: therapeutic photo-ablation with the excimer laser]. / Dystrophie de Reis-Buckler: photoablation thérapeutique au laser excimer.

PURPOSE: Reis-Buckler's corneal dystrophy consist of superficial reticulated opacities with recurring attacks of corneal erosion. Lamellar and penetrating keratoplasties were the traditional surgical means of improving recurrent erosions and vision but the dystrophy recurs following surgery. Phototherapeutic keratectomy (PTK) is now the standard method of managing this anterior corneal disease when intervention is required. MATERIAL AND METHODS: We have treated ten eyes with Reis-Buckler's dystrophy using Excimer laser PTK. RESULTS: All of patients achieved visual improvement (preoperative corrected visual acuity: average 0.3 +/- 0.2 SD, postoperative at one month 0.6 +/- 0.3 SD and 0.7 +/- 0.2 SD at one year. The refractive shift changed from a spherical equivalent of -0.92 D to a postoperative refraction of +1.80 D at one month and +1.65 D at one year.

[Biocompatibility of a porous alumina orbital implant. Preliminary results of an animal experiment]. / Biocompatibilité dans la cavité orbitaire d'une bille en alumine poreuse. Résultats préliminaires de l'expérimentation animale.

PURPOSE: Evaluation of clinical tolerance and scanning electron microscopy study of the bio-colonisation of a porous ceramical alumina implant after evisceration of the rabbit. Preliminary results. METHODS: Sixteen white New Zealand rabbits were eviscerated. A porous hydroxyde alumina ball was implanted in the opened sclera and explanted 15, 30, and 90 days after implantation. Clinical tolerance was assessed and implant tissular ingrowth was analyzed by scanning electron microscopy. RESULTS: One infection was observed and there was no conjunctival breakdown. Fibrovascular ingrowth occurred as soon as 15 days after implantation, and was full at one month. CONCLUSION: Porous alumina implant orbital tissue tolerance and fast fibrovascular ingrowth in the rabbit socket suggest promising result in the human anophthalmic socket.

[Combined phacoemulsificaion/membrane resection and macular edema]. / La chirurgie combinée phacoémulsification/pelage de membrane épirétinienne et oedème maculaire.

PURPOSE: To evaluate the occurrence of macular edema (ME) after epiretinal membrane resection, managed either with simple vitrectomy or with combined vitrectomy and phacoemulsification. MATERIAL AND METHODS: Two groups of 12 patients had a vitrectomy for epiretinal membrane associated or not to a phacoemulsification. A fundus fluorescein angiography was performed pre and postoperatively and at least 3 months after the surgery. RESULTS: In the group of patients who had a simple vitrectomy, a ME was observed in 50% of the cases preoperatively and in 25% of the cases at the end of follow-up. In 3 cases, preoperative ME was worsened after the surgery. In the group of patients who were treated by a combined vitrectomy and phacoemulsification, a ME was observed in 25% of the cases preoperatively and in 50% of the cases at the end of follow-up. A de novo ME was observed in 3 cases. CONCLUSION: Combined vitrectomy and cataract surgery could allow a rapid recovery of visual acuity but might increase the occurrence of ME.

[Uncommon corneal hydrops. Apropos of a case]. / Hydrops cornéen inhabituel. A propos d'un cas.

We report a case of corneal hydrops in a young patient with unremarkable ophthalmologic history or intercurrent identified pathology. Different etiologies of corneal hydrops are discussed.

[Retinal vasculitis]. / Les vascularites retiniennes.

PURPOSE: The purpose of this study is to determine aetiologies of vasculitis of retina in Morocco. MATERIAL AND METHODS: This is a retrospective study on 108 cases of vasculitis of retina admitted in the ophthalmology department, for a 5-year period (1987-1993). Our patients had a complete ophthalmological examination : fluorescine angiography, colour vision, general examination and biological study. RESULTS: Many aetiologies have been found, predominantly Behcet's disease. The neovascularization of retina which complicates the vasculitis was detected in 30 % of our patients. A laser photocoagulation was performed on these cases, sometimes a vitrectomy was necessary when a haemorrhage of vitreous body occurred, complicating the neo-vessels of retina. The therapeutics received by our patients was based on the corticotherapy. An immunosuppression treatment was prescribed in most cases of Behcet's disease and in severe vasculitis. Outcome after treatment has been satisfactory, but many patients relapse very frequently, mainly those with Behcet's disease. CONCLUSION: Causes of vascular retinitis are variable, most of them are due to Behcet's disease.

[Outcome of Behçet disease in ophthalmologic practice in Morocco]. / Devenir de la maladie de Behçet en milieu ophtalmologique marocain.

We treated 123 patients with Behçet's disease during a period of 10 years (1984-1993). The ocular lesions include uveal lesions especially the posterior lesions and vascular retinal. Uveitis was total in 72% of cases. Periphlebitis occurred in 51% of cases, vein occlusion in 10% of cases, macular oedema in 16% and papillary oedema in 10%. Clinical course and prognosis were studied. The functional prognosis is poor as such lesions may lead to blindness, particularly due to papillary oedema maculopathy. The treatment used is based on immunosuppressive and corticoid steroid drugs.

[Outcome of Behçet disease in ophthalmological milieu in Morocco]. / Devenir de la maladie de Behçet en milieu ophtalmologique marocain.

We treated 123 patients with Behçet's disease during a period of 10 years (1984-1993). The ocular lesions include uveal lesions especially the posterior lesions and vascular retinal. Uveitis was total in 72% of cases. Periphlebitis occurred in 51% of cases, vein occlusion in 10% of cases, macular oedema in 16% and papillary oedema in 10%. Clinical course and prognosis were studied. The functional prognosis is poor as such lesions may lead to blindness, particularly due to papillary oedema maculopathy. The treatment used is based on immunosuppressive and corticoid steroid drugs.