Eyeworld

EW NEWS & OPINION 18 S ickle cell disease (SCD)— often found in popula- tions of African descent but also appearing in non- black populations of Saudi Arabia and India—can have signifi- cant ocular manifestations, accord- ing to new research. Citing the incidence of prolifer- ative sickle retinopathy at 18% in the United States among those with SCD, a recent study further explored the ocular morbidity of patients with the disease. The study, published online in November 2010 in the European Jour- nal of Ophthalmology, investigated patients presenting with sickle cell disease for a routine follow-up at the Sickle Cell Clinic in Korle-bu Hospi- tal, Accra, Ghana. "Visual impairment was found in 5.6% of eyes examined," reported study co-author Martin M. Nentwich, M.D., ophthalmology department, Ludwig-Maximilian University, Munich, Germany, and colleagues. "Causes were cataract, proliferative sickle retinopathy [PSR], optic atrophy, phthisis bulbi, and central retinal artery occlusion." Vision loss is relatively uncom- mon in those with SCD, but ocular morbidity can be unique. "Although vision loss is uncommon in SCD, it is very important to those who end up with reduced visual acuity," Dr. Nentwich noted. Ocular problems Dr. Nentwich analyzed 201 patients (114 with the genotype HbSS and 87 with the genotype HbSC). "All patients had normal vision with their own correction or with pinhole in the better eye," Dr. Nentwich reported. "In patients with HbSS genotype 2/228 (0.9%) eyes had abnormal visual acuity, compared to 8/174 (4.6%) HbSC eyes. The difference in the number of visually impaired eyes in the two genotypes was statistically signifi- cant." Notable findings included the following: • Typical anterior segment SCD signs—even more common in HbSC patients—included tortuous corkscrew conjunctival vessels, iris atrophy, and cataract. • Eyes experiencing iris atrophy or depigmentation were found to be 1.8 times more at risk of PSR than eyes not affected by those condi- tions. • Of the subjects, 12.9% had PSR (3.5% of HbSS, 25.3% of HbSC; 15.9% of males and 11.2% of fe- males). • PSR prevalence increased with age and also with increased systemic severity of SCD. • Of the patients, 63% showed con- junctival signs. This is low com- pared to data from Kenya (87%) and Nigeria (77%–81%). • Cataracts occurred at a younger age (mean 39.9 years, range 32– 65) than in the general popula- tion. • Appearance of the black sunburst sign occurred more frequently in HbSC patients than in HbSS pa- tients and also correlated with in- creasing age. It's important to note that PSR prevalence varies in different coun- tries, largely depending on the geno- type and life expectancy of SCD patients, Dr. Nentwich noted. At least in Ghana, Dr. Nentwich is recommending a screening pro- gram. "In an environment with lim- ited resources, our analysis supports a PSR screening program which should consider HbSS adults with admissions per year >0.6 and all HbSC adults," Dr. Nentwich re- ported. "This protocol would leave out children, who have a PSR preva- lence of 1.5%, and HbSS adults with admission per year of life ≤0.6, who have a PSR prevalence of 3.6%. How- ever, all sickle cell patients with frank iris atrophy on anterior seg- ment examination should have a screening funduscopy to rule out PSR." Such a screening program is likely to succeed diagnostically, but then again, it likely would not pre- vent much blindness because these patients tend not to go blind. "By applying the screening pro- tocol as described above, only 78 of 201 patients, i.e., about 40%, would have to be examined and 24 out of the 26 PSR subjects would be diag- nosed," Dr. Nentwich reported. "Only two out of the 26 subjects with PSR (2 HbSS subjects) would not have been diagnosed correctly. However, the risk of blindness for these two patients is still very low due to the higher rate of a self-limit- ing course of disease in HbSS pa- tients." Mohan Rajan, M.D., medical director, Rajan Eye Care Hospital, Chennai, India, reported that sickle cell disease is rarely treated in India. However, the clinic does treat a vari- ant of SCD called Eales disease, he said. "Originally, people thought this disease was actually tuberculo- sis," Dr. Rajan said. "It appears com- monly in India. All clinical features are similar to sickle cell disease. It occurs more commonly in males than females." Of the patients that are coming to his clinic, at least one or two pa- tients a day have this disease. "They come with a sudden drop in vision like vitreous hemorrhage," Dr. Rajan said. "They come with floaters and very rarely have involvement of the macula. They can also have central retinal vein occlusion." EW Editors' note: Dr. Nentwich has no fi- nancial interests related to this study. Dr. Rajan has no financial interests re- lated to his comments. Contact information Nentwich: martin.nentwich@ med.uni-muenchen.de Rajan: rajaneye@vsnl.com May 2011 by Matt Young EyeWorld Contributing Editor Ocular problems can occur with sickle cell disease tact epithelium." Patients were fol- lowed for 26 months. "There was stabilization of the keratometry readings, and for some patients [these readings] even decreased," Dr. Kullman said. Overall, Dr. Kullman thinks that there's a lot of exciting femtosecond technology on the horizon. How- ever, she pointed out that there are still some logistics that need to be addressed. "I'm imagining doing cataract surgery with a laser and lo- gistically how that would work with transporting a patient from the laser to the OR suite or if it's possible to put the laser in the OR suite," Dr. Kullman said. "If we can get around those issues, I think that it's very promising and exciting for a certain subset of patients." EW Editors' note: Dr. Kullman has no financial interests related to her comments. Contact information Kullman: 508-842-3995, gkullman@ochsner.org Femtosecond continued from page 16

• Cover