advertisement

Editors Selection IGR 7-3

Medical treatment

Comment by Carl Camras on:

11678 Blood-aqueous barrier changes after the use of prostaglandin analogues in patients with pseudophakia and aphakia: a 6-month randomized trial, Arcieri ES; Santana A; Rocha FN et al., Archives of Ophthalmology, 2005; 123: 186-192

Find related abstracts

Arcieri et al. (277) describe some interesting results from an exceptionally well-controlled, well-designed, and well-balanced study. The authors' conclusions are supported by their results. Laudable is that the patients were followed for six months on treatment with all patients successfully completing the study except for those few who dropped out because of the development of cystoid macular edema (CME) by fluorescein angiography (FA). Although the study was not performed in a double masked fashion, it was observer masked. Although 80 patients were enrolled in the study, their distribution into the five groups led to only 15 to 17 patients per group, a relatively small number for evaluating between group differences. It is unclear how the higher prevalence at baseline of the diagnosis of secondary glaucoma (vs primary open angle glaucoma) in the unoprostone (UP) group (62%) compared with the bimatoprost (BP) group (31%) might have influenced the outcome. A breakdown of intraoperative complications among the groups was not specified, but would have been useful. Also important would have been specification of whether open posterior capsules resulted from previous Nd:YAG laser posterior capsulotomies or from intraoperative rupture with or without anterior vitrectomy. Differences in these factors among the groups at baseline might have translated into differences in the occurrence of CME. This specification is especially important since approximately one-half of the eyes in this study had open posterior capsules. Concerning the diagnosis of CME, it would have been helpful if the authors more clearly distinguished between leakage on FA without effects on visual acuity (VA) and 'clinical' CME defined as typical leakage on FA coupled with a reduction of VA. Of the six reports of 'CME' in this series, only one represented a case of 'clinical' CME. With the small number of patients in each of the four groups, no difference among the latanoprost (LP), travoprost (TP), and BP groups were demonstrated. These results are consistent with the very low incidence of 'clinical' CME developing in eyes treated with LP, even in those with risk factors.¹ These results also are consistent with another prospective, masked study demonstrating a high incidence of leakage by FA in eyes treated immediately before and after cataract surgery with LP, timolol, or vehicle with preservatives, but without the occurrence of 'clinical' CME.2,3 However, somewhat different from Arcieri et al., the Miyake et al. studies^2,3 failed to demonstrate a difference between the LP group and the vehicle with preservative group (or the timolol group) despite including over twice as many patients in each group. Many other differences among these studies might have accounted for these differing results. The study evaluating the effects of timolol, its preserved vehicle, and its non-preserved vehicle³ was not cited by Arcieri et al. Concerning the aqueous flare (AF) response determined with the sensitive Kowa laser flare meter, the results are similar to those obtained in two previous randomized, masked studies.^2,3 Miyake et al.^2,3 demonstrated that the AF response with LP at five weeks after cataract surgery was similar in the LP, timolol, and vehicle (with or without preservative) groups. These results are consistent with the AF response observed by Arcieri et al. in the LP, UP, and placebo groups. In general, multiple previous studies using fluorophotometry or the laser meter have not revealed an effect of LP on the blood-aqueous barrier, as previously reviewed.⁴ The six-month value for AF reported by Arcieri et al. was slightly, but significantly, greater in the TP or BP groups compared with either the LP, UP, or placebo groups. Whether this finding represents a real difference among the prostaglandin analogs must be verified in larger studies, especially since previous studies failed to show a prolonged effect on the blood-aqueous barrier of LP or any difference compared with timolol.^2-4 The significantly greater conjunctival hyperemia produced by BP more so than TP compared with LP is consistent with several previous large comparative clinical trials.^5-8 The reduction of conjunctival hyperemia with continued therapy¹ was not demonstrated in these previous studies^5-8 and must be confirmed. The persistently greater hyperemia in the BP group after six months of therapy is consistent with the previous publications.^6-8 Overall, this well-performed, but small study failed to demonstrate a significant difference in efficacy or CME ('clinical' or by leakage with FA) between LP, TP, and BP. BP and, to a lesser extent, TP produced more AF and conjunctival hyperemia. Some of these interesting findings must be verified in larger, controlled trials.

• ← Previous
• Next →