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Retina special report
However, the intravitreal implant was associated with a high rate of serious cat-aract progression and increased IOP when compared with standard of care, which consisted of macular laser treatment or observation, according to P. Andrew Pear-son, MD, professor and chairman, depart-ment of ophthalmology and visual science, University of Kentucky, Lexington.
Dr. Pearson presented the latest results in the ongoing trial of the implant (Control Delivery Systems and Bausch & Lomb), at the 2004 meeting of the Association for Research in Vision and Ophthalmology.
The rate of serious cataract progression was 77.4% for phakic patients who received the implant, while the rate among patients randomly assigned to standard of care was 13.3%. Rates of cata-ract extraction were 74.2% for the treatment group and 13.3% for the standard of care group.
The latest results from the six study sites also revealed that none of the standard of care patients experienced increased IOP, compared with 31.7% in the 0.5-mg treat-ment group.
However, most patients were able to con-trol their IOP with eye drops, Dr. Pearson said. Eight patients (19.5%) in the treatment group required trabeculectomy within the first 730 days following treatment.
In addition, 87.2% patients in the treat-ment arm had stable or improved diabetic retinopathy severity scores compared with 62.9% in the standard of care group.
"We know that worsening of this score puts the patient at higher risk for visual loss," Dr. Pearson said. "It's unclear exactly what an improvement in this score means for the patient's long-term visual outcome. We'll have to follow this to see what occurs."
The multicenter, randomized, controlled, masked study with an enrollment of 80 patients also produced a statistically significant resolution of macular edema at the center of the macula. There was no evidence of this type of edema in 53.7% of the treat-ment group versus 28.6% of the standard of care patients.
The overall change in total area of retinal thickness for all subfields was not statistically significantly different (p = 0.105). The mean change for the 0.5-mg treatment group was -4.75 ± 3.735 disc area (DA) and -3.28 ± 3.305 DA for the standard of care treatment arm. Measurement of change in retinal thickness was based on a five-step grading system in which 0 represented no edema and 4 represented edema greater than two times the thickness of the retina adjacent to the fovea.
The most recent results show a marked difference from earlier outcomes, Dr. Pearson said. Twelve-month results last fall also showed a reduction in retinal thickness, but there was no improvement in visual acuity among patients receiving the implant compared with those randomly assigned to standard of care.