RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE
■ AMD literature review. Doctors at the University of Colorado School of Medicine reviewed 244 articles in the medical literature on AMD, finding that the disease is more common and widespread than ever.
Among the authors’ findings were that the factors most strongly associated with progression to advanced AMD were smoking, previous cataract surgery, and age >60 years, while darker iris pigmentation demonstrated protective effects.
While Europe and North America have always had higher rates of AMD due to the predominance of people of European ancestry on those continents, rates in much of the developing world have increased despite the protection melanin affords, due to greater life expectancy in the developing world.
As a result, the authors concluded the economic burden of the disease will increase with time, unless more effective treatments emerge.
Velez-Montoya R, Oliver SCN, Olson JL, Fine SL, Quiroz-Mercado H, Mandava N. Current knowledge and trends in age-related macular degeneration. Retina. 2014;34:423-441.
■ More AMD data. A retrospective review of the fundus photographs of German patients found that more than one-third had small, hard drusen. By examining photos from the Gutenberg Health Study, the review authors also found early AMD in nearly 12% of the enrolled patients.
This rate of early AMD was found when examining all of the subjects as a single group. When examining age-specific subgroups, the authors found a rate of early AMD of 3.8% in subjects ages 35 to 44 years. However, no cases existed in this age group of geographic atrophy or wet AMD. Not surprisingly, the rate of advanced AMD increased with age.
The study provides additional data demonstrating that drusen are a normal part of the aging process and are not always associated with AMD. The study is limited by the homogeneity of its sample, although it might have implications for the United States, where a plurality of people are of German descent.
Korb CA, Kottler UB, Wolfram C, et al. Prevalence of age-related macular degeneration in a large European cohort: Results from the population-based Gutenberg Health Study. Graefes Arch Clin Exp Ophthalmol. 2014 Feb 25. [Epub ahead of print]
■ Microbial resistance and intravitreal injections. It’s well known that overtreatment with antibiotics results in microbial resistance, but is infection prophylaxis with intravitreal injections contributing to the problem?
To answer this question, a team of ophthalmologists at the Wills Eye Institute in Philadelphia, PA, conducted a prospective case series in 13 eyes of 13 patients receiving serial anti-VEGF injections for a variety of retinal diseases.
The authors obtained monthly conjunctival cultures to test for bacteria that had become resistant, despite not administering pre- or postoperative antibiotics and using only a topical anesthetic and povidone-iodine.
Seventy-seven percent of the cultures obtained were positive for microbes, but none of the samples was antibiotic-resistant.
The study authors concluded that povidone-iodine alone does not cause antibiotic-resistant flora to emerge, although they conceded that a longer study might have resulted in some resistance.
Hsu J, Gerstenblith AT, Garg SJ, Vander JF. Conjunctival flora antibiotic resistance patterns after serial intravitreal injections without postinjection topical antibiotics. Am J Ophthalmol. 2014;157:514-518.
■ OCT comparison study. Retinal physicians collaborating between Spain and the United States compared spectral-domain OCT to new swept-source OCT in the measurement of choroidal thickness.
The authors examined 82 healthy eyes of 46 patients, submitting all of the eyes to both imaging modalities. While three-quarters of eyes yielded choroidal thickness measurements using SD-OCT, the choroidal thickness of all eyes could be measured with SS-OCT. No significant differences emerged between thickness measurements between the two OCT types.
Based on their finding, the authors stated that SS-OCT is superior for the measurement of choroidal thickness. They recommended data be extrapolated with caution between the devices.
Copete S, Flores-Moreno I, Montero JA, Duker JS, Ruiz-Moreno J. Direct comparison of spectral-domain and swept-source OCT in the measurement of choroidal thickness in normal eyes. Br J Ophthalmol. 2014;98:334-338.
■ RVO treatments compared. Researchers at the University of York in the United Kingdom have found that the two most widely used pharmacotherapies for RVO are more effective than standard-of-case laser.
The researchers undertook a systematic review of 14 randomized, controlled trials. Both ranibizumab (Lucentis, Genentech, South San Francisco, CA) and the intravitreal dexamethasone implant (Ozurdex, Allergan, Irvine, CA) outperformed laser in terms of BCVA improvement. These improvements included patients with both branch and central RVOs.
Although these results are promising, the authors were quick to mention that without direct head-to-head comparisons, their findings are inconclusive. They urged the launch of such trials as soon as possible.
Glanville J, Patterson J, McCool R, Ferreira A, Gairy K, Pearce I. Efficacy and safety of widely used treatments for macular oedema secondary to retinal vein occlusion: a systematic review. BMC Ophthalmol. 2014;14:1-15.
■ Initial observation for VMA. Retinal physicians from practices in Florida, California, and Oklahoma found that vitreomacular adhesion could be managed favorably with initial observation.
The authors conducted a nonconsecutive case series of 106 eyes in 81 patients with VMA, detected via spectral-domain OCT. They also graded the VMAs on the basis of severity.
Over time, nearly one-third of the cases of VMA released spontaneously, while only five eyes were submitted to pars plana vitrectomy. Mean BCVA improved from 20/37 to 20/35 during the study.
Interestingly, the rate of spontaneous release was similar to that seen in the MIVI-TRUST trial of ocriplasmin (Jetrea, ThromboGenics, Iselin, NJ), suggesting that ocriplasmin may not be the optimal treatment for eyes with VMA but good vision.
Although the study was limited by its lack of patients with concurrent macular holes, the authors suggested that milder cases of VMA could be managed with observation.
John VJ, Flynn HW Jr, Smiddy WE, et al. Clinical course of vitreomacular adhesion managed by initial observation. Retina. 2014;34:442-446.
■ CMV retinitis without HIV. To examine the outcomes of patients with cytomegalovirus retinitis with HIV who were treated with ganciclovir (Cytovene, Genentech, South San Francisco, CA), ophthalmologists in India and Saudi Arabia performed a retrospective cohort study of 10 patients with the infection.
The patients enrolled in the study, six of whom were men, received an average of 5.54 ±3.36 injections and were completely healed at a mean of 1.81 ±1.25 months.
In addition, the study group reported one recurrence, while the rest of the patients remained disease-free with a mean follow-up of 9.46 ±12.42 months.
The authors concluded ganciclovir can safely and effectively treat CMV retinitis. The study fills an important gap in the literature because the vast majority of studies of CMV retinitis using antiviral drugs have focused on patients with HIV.
Agarwal A, Kumari N, Trehan A, et al. Outcome of cytomegalovirus retinitis in immunocompromised patients without Human Immunodeficiency Virus treated with intravitreal ganciclovir injection. Graefes Arch Clin Exp Ophthalmol. 2014 Feb 21. [Epub ahead of print]
■ Diagnosing uveitis vs lymphoma. Because some retinal disorders can masquerade as others, differential diagnoses can be challenging. Doctors at the NIH have responded to this difficulty with research showing how microRNA profiles may help distinguish uveitis from primary vitreoretinal lymphoma.
The samples were submitted to RT-PCR to detect genetic profiles. Seven lymphoma patients and 12 uveitis patients had ocular fluid samples taken. The samples were submitted to RT-PCR to detect genetic profiles. While several microRNAs appeared in both samples, only microRNA-155 was significantly more common in the samples from uveitis patients. While microRNA testing does not currently offer significant advantages over cytokine levels, the current measure, the study authors believe the use of microRNA-155 levels could play a role in the differential diagnosis.
Tuo J, Shen D, Yang HH, Chan C-C. Distinct MicroRNA-155 expression in the vitreous of patients with primary vitreoretinal lymphoma and uveitis. Am J Ophthalmol. 2014;157:728-734.
■ Side effects of retinoblastoma treatment. An ocular oncology team in upstate New York sought to determine the side effects of intravitreal injection therapy for retinoblastoma by conducting a literature review.
Identifying 10 studies on the topic in four databases, the authors obtained a total of 1,287 injections administered to 306 eyes of 295 patients over a mean follow-up period of 74.1 months.
Of these patients, 38 experienced ocular side effects, 17 of which were significant. These effects included iris atrophy and chorioretinal atrophy, vitreous hemorrhage, and retinal detachment.
Moreover, 61 of the patients had received injections using a safety-enhanced technique. In these patients, all side effects were caused by either the chemotherapy dose or other treatments.
In addition to the adoption of safer injection techniques, the authors recommended the use of electroretinography to track potential ocular toxicity to treatment.
Smith SJ, Smith BD, Mohney BG. Ocular side effects following intravitreal injection therapy for retinoblastoma: a systematic review. Br J Ophthalmol. 2014;98:292-297.
■ AMD and falls. The likelihood of both AMD and falls increases with age, and studies have shown the two are related. A study team from the Wilmer Eye Institute in Baltimore, MD, undertook a study to determine if AMD was correlated with fear of falling also.
One hundred twenty-five subjects with either AMD or suspected glaucoma completed the University of Illinois Fear of Falling questionnaire, and the authors submitted the responses to statistical analysis.
Subjects with AMD reported worse fear of falling than glaucoma suspects. They also suffered from worse VA and contrast sensitivity.
The authors suggested the need exists to address the fear of falling in elderly adults with AMD. RP
van Landingham SW, Massof RW, Chan E, Friedman DS, Ramulu PY. Fear of falling in age-related macular degeneration. BMC Ophthalmol. 2014;14:1-9.