Calculation of the power of anterior chamber implants.

Ninety seven eyes with anterior chamber implants and a best corrected visual acuity of at least 6/12 were studied, firstly, to compare the predictive accuracies of the commonly used formulas for intraocular lens (IOL) power calculation and, secondly, to determine the effect of optimising the 'A' constant on the predictive accuracies of the empirical Sanders-Retzlaff-Kraff (SRK) formulas. The accuracies of the empirical formulas (SRK and SRK II) were generally similar to those of the theoretical formulas (Binkhorst II and Colenbrander-Hoffer). However the original SRK formula was more accurate than the two theoretical formulas in long eyes and in all eyes overall. Optimisation of the 'A' constants did not improve the predictive accuracy of the empirical SRK formulas.

Metipranolol-induced adverse reactions: I. The rechallenge study.

Previously unreported adverse drug reactions can be difficult to detect and it may be even more difficult to establish a cause and effect relationship, particularly if the adverse reactions mimic naturally occurring disease. In a previous paper we reported 29 patients with granulomatous anterior uveitis, blepharoconjunctivitis, periorbital dermatitis, marginal keratitis and elevation in intraocular pressure (IOP), suspected to be caused by metipranolol (Glauline). With the approval of the District Ethics Committee 7 of those patients were rechallenged with metipranolol 0.3% compared to timolol maleate 0.5% in a double blind trial. The 7 metipranolol treated eyes developed an adverse reaction within 14 days. Metipranolol (Glauline) has been conclusively proven to cause granulomatous anterior uveitis, blepharoconjunctivitis and elevation in IOP, adverse effects never previously reported with any of the ophthalmic topical beta-blockers. The multidose preparations of metipranolol (Glauline) in all three strengths 0.1%, 0.3% and 0.6% and the single dose minim preparation of metipranolol 0.6% have now been withdrawn from clinical use in the United Kingdom.

Metipranolol-induced adverse reactions: II. Loss of intraocular pressure control.

This paper reviews the behaviour of intraocular pressure (IOP) in glaucomatous eyes treated with metipranolol with and without drug-induced adverse reactions (ADRs). Two hundred and forty seven patients with open angle glaucoma who were receiving the three different strengths of metipranolol (0.1%, 0.3%, and 0.6%) in our Department and the 7 patients who participated in the metipranolol rechallenge trial were included in this study. Out of the 247 patients, there were 52 eyes of 29 patients who showed 78 episodes of ADRs associated with metipranolol. Forty five of these 78 episodes (57.6%) were associated with loss of IOP control. Two of the 7 eyes treated with metipranolol in the rechallenge trial showed loss of IOP control, 1 of them without any signs of ocular inflammation. We further studied all the glaucomatous eyes controlled with metipranolol 0.6% only and 22 eyes were identified with loss of IOP control but without recognisable signs or symptoms of ADR. Five other eyes in this group later developed metipranolol-induced ADRs. The possible pathophysiological mechanisms for the loss of IOP control are discussed and it is suggested that the active drug, metipranolol, could be directly implicated.

Metipranolol-associated granulomatous anterior uveitis.

This paper presents for the first time documented evidence, clinical details, and photographic illustrations of metipranolol-associated granulomatous anterior uveitis in 26 eyes of 15 patients being treated for glaucoma. There were 56 episodes of granulomatous anterior uveitis, all associated with large (mutton-fat) keratic precipitates, flare, cells, and 'white eyes' (except in seven episodes). In 30 (53.6%) of these episodes there was loss of control of intraocular pressure. Metipranolol 0.6% was implicated in 54 of the 56 episodes and metipranolol 0.3% in the remaining two. Fifty-one other cases of metipranolol-associated granulomatous anterior uveitis have so far been reported from other parts of the country to the Committee on Safety of Medicines. As a result multidose metipranolol in 0.1%, 0.3%, and 0.6% strengths has been withdrawn from clinical use in the United Kingdom. The pathogenesis of this adverse drug reaction is uncertain.

Clinical evaluation of automated refraction in anterior chamber pseudophakia.

Automated refraction with the Canon RK-1 Autoref keratometer was evaluated in 85 eyes of 85 patients with an anterior chamber intraocular lens implant and a best corrected visual acuity of at least 6/12. Autorefraction readings were obtained in 80 (94%) of these eyes. The agreement between autorefraction and clinical refraction data was 89% for spherical equivalence less than 0.51 dioptres (D), 91% for sphere power less than 0.51 D, 82% for cylinder power less than 0.51 D, and 91% for cylinder axis less than 11 degrees. Autorefraction provides acceptably accurate postoperative refraction values in anterior chamber pseudophakia.

Objective autorefraction in posterior chamber pseudophakia.

Automated refraction with the Canon RK-1 Autoref keratometer was evaluated in 110 eyes (110 patients) six to eight weeks after they had undergone extracapsular cataract extraction with posterior chamber intraocular lens implantation and achieved a best corrected visual acuity of at least 6/12. Autorefraction readings were obtained in 100 (91%) of these eyes. The agreement between autorefraction and clinical refraction data was 98% for spherical equivalence less than 0.51 dioptres (D), 95% for sphere power less than 0.51D, 94% for cylinder power less than 0.51D, and 85% for cylinder axis less than 11 degrees. Autorefraction can provide acceptably accurate postoperative refraction values in pseudophakic eyes.

Double-blind controlled trial to compare anti-inflammatory effects of tolmetin 2%, prednisolone 0.5%, and placebo in post-cataract extraction eyes.

This paper compares the efficacy of tolmetin, prednisolone, and placebo (vehicle only) in controlling post-cataract extraction inflammation in a double-blind trial involving 120 patients. Seventeen patients were excluded from analysis. The results of the 103 patients analysed showed that 94% of the prednisolone treated group was judged to have been successfully treated as compared with 53% of the tolmetin treated group and 46% of the vehicle treated group. The differences between the prednisolone treated group and the other two groups were statistically significant (p less than 0.001). No statistical significance was found between the tolmetin and vehicle groups.

Double-masked controlled clinical trial of 5% tolmetin versus 0.5% prednisolone versus 0.9% saline in acute endogenous nongranulomatous anterior uveitis.

A double-masked controlled clinical trial of 5% unpreserved tolmetin versus 0.5% prednisolone versus 0.9% saline in acute endogenous nongranulomatous anterior uveitis was carried out on 100 patients. 69% of the prednisolone-treated patients were judged "cured" at the end of the 3-week study. This is compared with a cure rate of 47% for the tolmetin-treated patients for 53% for the placebo (saline) group. No statistically significant difference was established between the 3 groups.