RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE
■ RP repair patterns. In the June 2012 issue of the American Journal of Ophthalmology
More than 20,000 RP repair surgeries were conducted in 2009, according to Medical Part B data, with the majority (16,101) performed by pars plana vitrectomy. The remaining cases were performed by either pneumatic retinopexy (3,199) or scleral buckling (2,313).
Among the trends identified by Dr. Hwang were that the Midwest had a greater preference for scleral buckling than other regions and a lower preference for pars plana vitrectomy in comparison with the South and West. Pneumatic retinopexy was more common in the Northeast, while in the same region, PPV was practiced less often, although this last measurement was not statistically significant.
Among other conclusions, Dr. Hwang notes that despite its historical association with pneumatic retinopexy (the procedure was introduced in 1986 in California), the Medicare data revealed that the West does not currently have a greater preference for this technique.
■ Lucentis data. Scientists from Australia, Europe, and the United States have collaborated on a study of the data from the RESTORE trial of Lucentis for diabetic macular edema to evaluate the drug's cost-effectiveness as monotherapy or in combination with laser in comparison to laser alone. They report their outcomes in the May 2012 issue of the British Journal of Ophthalmology.
The authors constructed a Markov model to simulate the 12-month outcomes and costs of treating DME in one eye. They measured outcomes in quality-adjusted life years (QALYs) and estimated the data out to 15 years, taking into account the costs of treatment, disease monitoring, and vision loss.
Based on their statistical analysis, the authors found that Lucentis monotherapy resulted in a gain of 0.17 QALYs at an incremental cost of £4,191 (equivalent to approximately $6,570) in comparison to laser alone, yielding a cost-effectiveness ratio of £24,028 (more than $37,000).
Subsequent analyses revealed that there was a 64% probability of the drug being cost-effective at £30,000 (~$47,000) per QALY. Combination therapy resulted in a 0.13 QALY gain at a cost of £4,695 (~$7,350) compared to laser alone, which was 42% likely to be cost-effective at the threshold of £30,000.
The authors conclude that despite its high cost, Lucentis monotherapy is cost-effective relative to laser monotherapy, while the cost-effectiveness of combo therapy is less certain. As a study limitation, it should be noted that several of the authors of the study are employees of Novartis.
Elsewhere in the recent research, a small study of Lucentis combination therapy with proton beam irradiation for wet AMD was published in May 2012 issue of Retina. The authors of that study found limited improvement but no radiation-related side effects. A more comprehensive, larger study is under way.
■ To peel or not to peel? Whether to peel the internal limiting membrane during vitrectomy (Figure 1) remains a topic of debate, and an article in the May 2012 issue of Retina adds ammunition to the pro side of the discussion. Surgeons from departments of ophthalmology in Missouri, Michigan, Minnesota, and California collaborated on this literature review.
Figure 1. ILM peeling after staining with brilliant blue G.
In the review, the authors consider several indications for ILM peeling, including full-thickness macular hole, epiretinal membrane, DME, and RVO-related macular edema. Furthermore, they review several surgical techniques, instruments, and adjunctive treatments and address the possible complications of the peeling procedure.
The authors review a total of 140 articles published on the topic of ILM peeling, so the article is sure to contribute to the ongoing discussion of this procedure.
■ Retinoblastoma study. Retinoblastoma (Figure 2) remains one of the most common malignancies in children, although it is highly curable. In an attempt to evaluate recent outcomes based on invasion of the choroid, optic nerve, and anterior segment and on pretreatment grading, a team of retinal physicians in Argentina undertook a retrospective study of four clinical trials conducted between 1989 and 2010. They report their findings in the June 2012 of Archives of Ophthalmology.
Figure 2. The left eye of a child with large macular retinoblastoma before treatment.
From the four previously executed trials, the study authors enrolled 167 children in their retrospective analysis. Of these children, 35 had massive invasion. Nevertheless, the analysis revealed that the probability of fiveyear survival among these patients was 98.1%. Overall survival was even better, at 98.7%, because of the relapse of one patient. While the 35 patients with massive invasion had significantly lower event-free survival than those with focal invasion (94.2% vs 99.2%; P = .04), overall survival between these two groups was not significantly different.
The findings on survival in these four trials was deemed excellent by the Archives authors, particularly given that no adjuvant therapy was administered. While the study confirms that extraocular relapse is more common in children with massive invasion, that there was no significant difference in overall survival between these children and those without massive invasion is good news for ocular oncology.
■ Endophthalmitis comparison study. Endophthalmitis can occur following both intravitreal injections and phacoemulsification. But for which surgery is the risk greater? To answer that question, ophthalmologists in Sydney, Australia, published a study in the June 2012 issue of the British Journal of Ophthalmology analyzing some of the available data.
In this retrospective case series, patients submitted to either phaco or an intravitreal injection between 2007 and 2010 were analyzed for the following factors: (1) pathogenic organism; (2) time to presentation of endophthalmitis; (3) odds of improvement in visual acuity; (4) odds of final VA of counting fingers; and (5) odds of enucleation.
One hundred one patients were eventually enrolled, and 48 had been operated on for cataracts, while the remaining 53 had received intravitreal injections. All of the enrolled patients were treated for endophthalmitis.
Endophthalmitis caused by Streptococcus species was more common in the intravitreal injection group (24.53% vs 6.25%). Furthermore, the cases following intravitreal injections were more likely to result in VA of counting fingers of less. Cases caused by Streptococcus species, whether post-phaco or postinjection, were more likely to result in final VA of counting fingers or less and in enucleation.
Given that Streptococcus species tend to arise from the oral flora, the authors of the BJO study review the precautions commonly used during intravitreal injections, but they caution that the data on these precautions are inconclusive.
■ Early AMD study. Scientists in Illinois have published two-year data from a pilot study of the use of optical coherence tomography to detect early exudative AMD. Their article appears in the June 2012 issue of Retina.
All of the enrolled patients underwent examinations and OCT every three months for two years. Of the 79 patients who were diagnosed with dry AMD in one eye and wet AMD in the other, 15 eventually developed wet AMD in their dry AMD eyes. Of these 15 patients, 13 demonstrated disease progression on OCT before either ophthalmoscopic and biomicroscopic examinations or fluorescein angiography detected progression from dry to wet AMD.
These results, though limited by the small sample size, indicate that OCT could emerge as a useful tool in the diagnosis and prognosis of AMD. Stressing the importance of early detection of choroidal neovascularization, the study authors urge the undertaking of larger trials, as well as extending fluorescein angiography beyond 10 minutes, the latter of which might help detect early wet AMD cases. RP