April 2008

 

OPHTHALMOLOGY NEWS

 

Implant complication manageable


by Rich Daly EyeWorld Contributing Editor

 

 

Findings confirm previous reports that these devices provide a viable uveitis treatment alternative to systemic medication

Fundus images of in vitro fluocinolone acetonide intravitreal implants Source: Quan Dong Nguyen, M.D.

Uveitis treatment with fluocinolone acetonide (FA) intravitreal implants frequently results in elevated intraocular pressure (IOP), but such increases are “manageable” with medication and IOP-lowering surgery, according to a recent study.

Pooled data from three multicenter, double-masked, randomized, controlled, clinical trials of 2.1 mg and 0.59 mg Retisert (fluocinolone acetonide, Bausch & Lomb, Rochester, N.Y.) FA intravitreal implants compared with standard uveitis therapy were published in the November 2007 issue of the Archives of Ophthalmology.

The results, including a three-year follow-up, showed 71% of implanted eyes had an IOP increase of 10 mm Hg or more than baseline, and 55% of eyes reached an IOP of 30 mm Hg or more.

Seventy-five percent of the eyes received topical IOP-lowering medication and 37% underwent IOP-lowering surgery—usually trabeculectomy.

The study authors found that IOP-lowering procedures were successful at establishing post-op IOPs of 6 to 21 mm Hg in 85% of eyes after one year.

Further findings included a similar hypotony rate in both eyes that underwent IOP-lowering surgery (43%) and implanted eyes not subjected to surgery (36%).

“When surgery was required, rates of complete or qualified surgical success were high,” wrote the authors, led by Debra A. Goldstein, M.D.

They concluded that ophthalmologists should balance the need to manage elevated IOP as an adverse event following treatment with the FA intravitreal implant against the “excellent efficacy of the FA intravitreal implant in reducing uveitis recurrence.”

Treating physicians should discuss with prospective FA implant recipients the very real possibility of marked elevation in IOP secondary to the implant, and be prepared for the medical and surgical treatments that likely will be needed.

It’s a conclusion that was shared by Quan Dong Nguyen, M.D., assistant professor of ophthalmology, Vitreous-Retina Service, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore.

“The important thing is that one has to consider the risk of this complication versus the complications of not using this implant,” Dr. Nguyen said, about problems that can arise from the more commonly used uveitis treatment of systemic administration of corticosteroids. Targeted biological agents also are increasingly used as corticosteroid-sparing therapies.

A discussion with candidates for the FDA-approved implant should assess their willingness to put up with the risk for developing cataracts or ocular hypertension that might require surgical or medical management.

The discussion should weigh those concerns with the benefits of FA implants, which include elimination of daily medication, fatigue, sickness, and potential facial hair growth, against the potential complications from the use of systemic uveitis medications. “Unfortunately there is no perfect solution in the management of uveitis yet,” said Dr. Nguyen, who has implanted about 100 such devices noted, “In the meantime, the fluocinolone acetonide—when used in appropriate situations—is a very worthy approach.”

An ideal candidate for the implant, according to Dr. Nguyen, has unilateral uveitis that is non-infectious. Another good candidate is a patient with asymmetric uveitis in which one eye is much more severely inflamed than the other. In such cases surgeons could put an implant in the more diseased eye, while providing a low dose of systemic medications for the fellow eye.

Uveitis has long been associated with elevated IOP. Previous research has found elevated IOP occurs in up to 26% of patients with acute uveitis and up to 46% of patients with chronic uveitis, and the risk of elevated IOP has been shown to increase over time, the study authors noted.

The study supports previous research that found all corticosteroid administration routes are associated with elevated IOP, and local ocular administration is associated with a greater risk. The extent of IOP elevation, the study authors noted, depends on the potency of the corticosteroid, the dose and duration of treatment, the route of administration, and the patient’s susceptibility to corticosteroid-induced ocular hypertension.

“Hence, in patients with uveitis with corticosteroid treatment, elevated IOP may be the result of the corticosteroid treatment and/or the uveitis itself,” the authors said.

The study noted that although few eyes required explantation of the FA device, the incidence of elevated IOP with the implant was higher than that of other published studies. The authors said the higher incidence of elevated IOP with the FA intravitreal implant may be related to constant exposure to corticosteroid throughout the implant’s 30-month lifespan, which differed from previous research with eyes exposed to fluctuating corticosteroid levels through injections every three months.

Dr. Nguyen said ophthalmologists should expect the development of elevated IOP, look for it, and then treat it aggressively in its early stages. Dr. Nguyen photographs the optic nerve, documents patient IOP, and obtains a baseline visual field before implanting patients with the device to provide the basis for later assessment.

“I prepare myself and prepare the patient by obtaining baseline estimates so there will be no surprises,” he said.

The future use of FA implants, Dr. Nguyen said, would benefit from further research on best locations for the implant, shortened terms of implantation, and the use of lower doses than the lowest (.95 mg) used in this study.

Editors’ note: Dr. Nguyen is a member of the uveitis advisory board of Bausch & Lomb (Rochester, N.Y.). He notes that the views expressed are his and not those of Johns Hopkins.

Contact Information

Nguyen: 410-502-5383, qnguyen4@jhmi.edu

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