RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE
■ Combination therapy for retinoblastoma. Pretreatment with a subconjunctival bleb of chemotherapy prior to intravitreal chemotherapy in patients with retinoblastoma (Figure 1) might reduce the risk of orbital tumor seeding. A small case series reported in the August 2012 issue of the British Journal of Ophthalmology had positive results.
Treating two children with retinoblastoma who had failed prior systemic chemo, doctors at the Mayo Clinic administered the patients with a single subconjunctival injection of 0.5 mL carboplatin, 0.05 mL of which was injected into the vitreous. After enucleation of the treated eyes, the eyes did not show malignant seeding, nor was there toxicity delivered to the retina or anterior segment. No orbital malignancy occurred at 37 months of follow-up.
While the article presents a rather low level of evidence, it does offer some hope for the improvement of chemotherapy protocols in children with retinoblastoma.
Figure 1. Fundus photograph of a 16-mm retinoblastoma tumor following treatment with chemotherapy.
IMAGE FROM GOMBOS DS, KELLY A, COEN PG, KINGSTON JE, HUNGERFORD JL. RETINOBLASTOMA TREATED WITH PRIMARY CHEMOTHERAPY ALONE: THE SIGNIFICANCE OF TUMOUR SIZE, LOCATION, AND AGE. BR J OPHTHAMOL. 2002;86:80-83. REPRINTED WITH PERMISSION OF BMJ JOURNALS.
■ Choroidal thickness in early AMD. To determine whether there is any correlation between the thickness of the choroid and features on fundus photography in early AMD, retinal physicians in New York undertook a study of 70 patients with the disease. They reported their findings in the July 2012 issue of Retina.
Ninety eyes of these 70 patients submitted to enhanced depth imaging OCT and multimodal imaging were retrospectively evaluated, and their charts were reviewed for refractive error, hypertension and diabetes, and other relevant factors. The mean VA of the cohort was 20/31.
The study authors found that sub-foveal choroidal thickness was inversely correlated with age and increasing myopia. Eyes with fundus tessellation subretinal drusenoid deposits, and RPE abnormalities on OCT had thinner choroids.
The study is important in that it offers evidence for certain associations that occur in the AMD disease process, particularly given the genetic associations that have been detected between thinning choroids and certain phenotypes of AMD genes.
■ Blood pressure and retinal vessels. The Beaver Dam Eye Study has offered invaluable data to ophthalmologists with its 20-year follow-up. The August 2012 issue of Archives of Ophthalmology features the latest analysis of these data, an attempt to correlate blood pressure with retinal arterioral diameter.
This particular study examined retinal arterioral diameter in 4,573 subjects over 15 years. After adjusting for image quality, refractive error, lens status, and age, systolic blood pressure was found to be associated with retinal arterioral diameter, as were smoking status, BMI, alcohol consumption, and other factors. Use of calcium channel blockers seemed to affect this relationship, but not other hypertension-controlling drugs.
With these data, doctors may be better able not only to screen patients for retinal vascular disease, but also to screen them for systemic vascular disease. Nevertheless, the authors caution that prospective studies must be undertaken to confirm their findings.
■ Triamcinolone and endophthalmitis. With widespread use of triamcinolone acetonide in the retina subspecialty, scientists in South Korea under took an investigation of the factors associated with and outcomes of cases of endophthalmitis in patients receiving such injections. Graefe's Archive for Clinical and Experimental Ophthalmology posted their findings online in July. Undertaking a retrospective evaluation of 186 patients who received 219 injections, the study authors identified six cases of presumed noninfectious endophthalmitis. Previous vitrectomy, pseudophakia, and a history of intravitreal triamcinolone injections were all significantly associated with endophthalmitis. ILM peeling during vitrectomy was also associated with infection. Five of patients recovered their pretreatment VA.
The authors believe the particular formulation of triamcinolone used in the cohort of studied patients played a role in causing endophthalmitis in the six identified patients, although the clustering of cases in a particular year of the study indicated exogenous contamination. Nevertheless, they suggested that retinal physicians using triamcinolone in their patients screen them for the identified risk factors. RP