Intra-ocular concentration-time relationships of subconjunctivally administered gentamicin.

Eighty-nine patients scheduled for cataract removal or lens implantation were divided randomly into three groups. Each received 5, 10 or 20 mg gentamicin subconjunctivally at times varying between 0.2 and 19 hours pre-operatively. At surgery a sample of aqueous humour was obtained and analysed for gentamicin concentration. The data for each group were subjected to non-linear regression analysis to fit an open one-compartment pharmacokinetic model with first-order kinetics. A statistically acceptable fit was obtained. The average values of the pharmacokinetic parameters obtained from the single doses were used to simulate multiple-dose kinetics. The average target intra-ocular gentamicin concentrations and dosage interval were specified in the computer program, which subsequently allowed calculation of the dose required. This allowed the construction of a simple linear nomogram that can be used to read off the dose needed for handling specific clinical situations.

Outpatient treatment of retinal detachment.

Outpatient treatment of retinal detachment is a new concept. The first 20 cases treated in the Department of Ophthalmology at Tygerberg Hospital are discussed. After an inert gas has been injected into the vitreous cavity the patient is allowed to go home, where he must remain in the therapeutic position. When the patient returns the next day the retina will usually be reattached around the breaks, and laser photocoagulation or cryopexy is performed. The success rate is high, and this procedure should be considered in all cases in which it is indicated.

The organisation of an ophthalmological service for diabetics in a teaching hospital.

A new system of ophthalmological evaluation of diabetic patients in a teaching hospital has been devised. All the patients attending the diabetic clinic were screened by ophthalmologists. Any patient with a problem was then referred to a diabetic ophthalmology clinic where a full evaluation was done and treatment given where necessary. In an 18-month period 1,015 new ophthalmological diabetic patients were screened. Of these patients 13.6% had background retinopathy, 8.4% pre-proliferative retinopathy and 3.4% proliferative retinopathy, while 8.6% had maculopathy. These results show that even in a teaching hospital a significant percentage of patients already have pre-proliferative or even proliferative retinopathy when seen by an ophthalmologist for the first time. The importance of organising an ophthalmological service for the diabetic patient is stressed.

[Brucella keratoconjunctivitis]. / Brucella-keratokonjunktivitis.

A case is described in which the rubber cap of a vial containing Brucella abortus vaccine came off accidentally and some of the contents splashed in the eyes of a veterinarian. A uni-ocular keratoconjunctivitis developed. The other eye was similarly affected 1 week later. Brucella tests were negative. Two months later the Br. abortus titre was 1/640 and the Br. melitensis titre 1/320. Systemic treatment with tetracyclines, co-trimoxazole and streptomycin and local treatment with chloramphenicol and atropine had no effect. Two attacks of acute keratoconjunctivitis subsequently occurred within two hours of handling Brucella vaccine. In the right eye a corneal abscess developed, as well as uveitis and cataract. Extracapsular lens extraction was performed. Panophthalmitis followed and the eye was enucleated. The literature is reviewed and the possibility of a Brucella keratoconjunctivitis indistinguishable from viral keratoconjunctivitis is discussed.

Implants for draining neovascular glaucoma.

The implant design, surgical technique, and pharmacological methods of controlling bleb fibrosis, used to treat neovascular glaucoma, are described, together with the results of 14 operations performed on 12 eyes.