JOURNAL CLUB

RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE

■ Coffee and the choroid. A single cup of coffee can decrease choroidal thickness for as long as four hours, according to a Turkish team of retinal physicians.

In a prospective study, 62 healthy subjects drank a 100-mL cup of Turkish-style coffee containing 57 mg of caffeine and then underwent enhanced depth imaging (EDI)-OCT seven times over the course of the subsequent six hours. Another 54 subjects who served as controls drank water.

Choroidal thickness was significantly lower in the study group at five minutes and at one, two, three, and four hours after drinking coffee. By six hours, however, the difference disappeared.

In addition, the authors found that the changes in choroidal thickness were positively correlated with age and negatively correlated with height, which the authors believe is linked to general circulatory factors.

Vural AD, Kara N, Sayin N, Pirhan D, Ersan HBA. Choroidal thickness changes after a single administration of coffee in healthy subjects. Retina. 2014;34:1223-1228.

■ Fellow eyes in macular hole. Ophthalmologists in India and Bangladesh sought to determine the features on spectral-domain OCT of the fellow eyes of eyes diagnosed with idiopathic macular hole.

The authors conducted a retrospective analysis of 101 fellow eyes of 101 patients with full-thickness macular holes, comparing the findings on SD-OCT with those from 101 age-matched controls.

Only seven of the fellow eyes had macular holes. However, the incidences of vitreomacular traction, epiretinal membranes, lamellar holes, and inner foveal splits were all higher in the fellow eyes, while posterior and perifoveal vitreous detachments were more common in the control eyes.

The study authors concluded that a need exists to perform SD-OCT on the fellow eyes of patients with idiopathic macular holes, and they identified a link between vitreoretinal interface abnormalities and hole formation.

Chhablani J, Kumar K, Ali TR, Narayanan R. Spectral-domain optical coherence tomography features in fellow eyes of patients with idiopathic macular hole. Eur J Ophthalmol. 2014;24:382-386.

■ Predicting retinal thickness. Patients have undergone long treatment durations as OCT technology has changed, making it difficult in some cases to track retinal thickness accurately. Doctors in Singapore compared retinal thickness measurements on time-domain (TD) and SD-OCT to determine whether the parameter could be predicted.

The authors prospectively submitted 200 eyes of 100 healthy subjects to measurements with both OCT types. They generated four mathematical formulas with data from the first 60 eyes, which they then applied to the data from the subsequent 140 eyes. Their goal was to determine whether TD-OCT measurements could be used to predict thickness on SD-OCT.

Of the four computational methods applied, three of them predicted retinal thickness on SD-OCT with intraclass correlation coefficients >0.88. In 60% of the eyes, the predicted measurement and actual measurement differed by 5 µm or less.

While the authors cited the standard study limitations inherent in studying healthy volunteers, they concluded that it is possible to predict SD-OCT data mathematically on the basis of TD-OCT data.

Tan CS, Li KZ, Lim TH. Calculating the predicted retinal thickness from spectral domain and time domain optical coherence tomography – comparison of different methods. Graefes Arch Clin Exp Ophthalmol. 2014 May 27. [Epub ahead of print]

■ LUCIDATE data. The one-year data from the LUCIDATE trial, conducted in London to compare ranibizumab (Lucentis, Genentech, South San Francisco, CA) to laser for treatment of DME, indicated a clear advantage of ranibizumab.

Thirty-three eyes of 33 patients with center-involving DME were randomized at a 2:1 ratio to three monthly doses of ranibizumab or macular laser therapy every 12 weeks. The authors measured several outcomes at 12, 24, and 48 weeks, including visual acuity and OCT measurements of retinal thickness.

While the patients who received ranibizumab gained an average of 6.0 letters of VA, the laser-treated patients lost an average of 0.9 letters. Ranibizumab was also more effective in reducing retinal thickness on OCT.

The study adds to the growing body of evidence suggesting that anti-VEGF therapy is superior to laser for treating DME. Ranibizumab has been FDA-approved for this indication since August 2012.

Comyn O, Sivaprasad S, Peto T, et al. A randomized trial to assess functional and structural effects of ranibizumab versus laser in diabetic macular edema (the LUCIDATE study). Am J Ophthalmol. 2014;157:960-970.

■ Colored perfluorocarbon for surgery. Scientists in Sao Paulo, Brazil, recently developed and tested a colored perfluorocarbon liquid, to be used as a tamponade in vitreoretinal surgery.

The scientific team colored perfluorohexyloctane (F6H8; Fluoron GmbH, Ulm, Germany) by adding 0.3 g/L of blue anthraquinone dye. The colored perfluorocarbon was then mixed with one of two other perfluorocarbons and applied to a mouse cell line and injected into pig eyes. Finally, a pilot prospective study examined the liquid in nine eyes of human patients.

In pig eyes, the new colored perfluorocarbon neither stained the inner limiting membrane nor formed residual intravitreal droplets. In the nine human eyes, which had undergone vitrectomy of retinal detachment, the liquid enhanced visualization without causing leakage.

The authors intend to improve upon the initial formulation and to conduct long-term electroretinographic studies to determine the effects of the liquid.

Rodrigues EB, Shiroma H, Penha FM, et al. Development and initial experience with a colored perfluorocarbon liquid for intraocular tamponade in vitreoretinal surgery. Retina. 2014;34:1103-1111.

■ Macular edema following PRP. Because macular edema remains a risk following panretinal photocoagulation, ophthalmologists in South Korea undertook a medical record review to determine the risk factors for post-PRP macular edema, using SD-OCT.

Of 129 eyes with diabetic retinopathy submitted to PRP, 11 developed macular edema within one month. Baseline central retinal thickness and subretinal fluid on OCT were both significantly associated with post-PRP macular edema. Only two of 97 eyes without cystoid spaces developed edema.

While they acknowledge the limitations of a retrospective study, the authors suggested that SD-OCT could be used before PRP to determine whether a greater-than-normal risk exists for post-PRP macular edema.

Oh J-H, Kim S-W, Kwon S-S, Oh J, Huh K. The change of macular thickness following single-session pattern scan laser panretinal photocoagulation for diabetic retinopathy. Graefes Arch Clin Exp Ophthalmol. 2014 May 27. [Epub ahead of print]

■ CSC and temperament. Is there a link between central serous chorioretinopathy and personal temperament? To answer this question, doctors in Poland applied a questionnaire in patients diagnosed with CSC and in healthy controls.

Thirty-two patients with CSC and 30 healthy age- and sex-matched controls completed the Temperament and Character Inventory, a self-report inventory of personality traits developed in the 1990s.

The authors found that patients with CSC scored significant higher on the part of the questionnaire that measures harm avoidance. They also found differences in behaviors related to novelty seeking and reward dependence, but these differences were not statistically significant.

Moreover, patients with CSC had less tolerance of frustration and higher levels of insecurity and participatory anxiety. The study results add to the evidence suggesting links between psychological stress and CSC.

Piskunowicz M, Jaracz M, Lesiewska H, Malukiewicz G, Brozek-Pestka M, Borkowska A. Temperament profile in patients with central serous chorioretinopathy: a case-control study. Eur J Ophthalmol. 2014;24:392-395.

■ Nanoparticle therapy for retinoblastoma. Ocular oncologists in India recently tested polymethylmethacrylate nanoparticles loaded with carboplatin (Paraplatin, Bristol-Myers Squibb, New York, NY) to treat retinoblastoma.

Six patients, with a mean age of 26.83 years (±7.5 years) and who were scheduled for enucleation, received sub-Tenon’s injections of 10 mg/mL carboplatin. The eyes were subsequently enucleated in groups of two at six, 24, and 72 hours postinjection.

The highest level of carboplatin reaching the retina was found in the eyes enucleated at 24 hours. The choroids and lenses showed low levels at six hours and negligible levels at 72 hours. No signs of ocular tissue damage were found and the drug was not detectable in the circulation

While the study results indicated that nanoparticle delivery of carboplatin could be useful in treating retinoblastoma with minimal toxicity to surrounding tissues, further studies will need to establish clinical efficacy.

Kalita D, Shome D, Jain VG, Chadha K, Bellare JR. In vivo intraocular distribution and safety of periocular nanoparticle carboplatin for treatment of advanced retinoblastoma in humans. Am J Ophthalmol. 2014;157:1109-1115.

■ Vitrectomy for floaters. The performing of vitrectomy for vitreous floaters is controversial, but complex cases can call for the procedure. To determine how effective the surgery is in these cases, retinal physicians in Birmingham, AL, conducted a clinical study.

The authors conducted a retrospective chart review of 168 eyes in 143 patients who received vitrectomy for floaters over two years. They collected data on outcomes, as well as responses on a nine-item quality of life survey.

Mean VA improved from 20/40 preoperatively to 20/25 postoperatively. Twelve of the eyes experience iatrogenic retinal breaks, and three eyes experienced complications of cystoid macular edema (one case) or vitreous hemorrhage (two cases).

Of the nearly 90% of patients who completed the quality of life survey, 96% reported satisfaction with the procedure.

The authors concluded sutureless vitrectomy should be considered in patients with symptomatic floaters. They believe that quality of life should be a major consideration of treating physicians in such cases. RP

Mason JO III, Neimkin MG, Mason JO IV, et al. Safety, efficacy and quality of life following sutureless vitrectomy for symptomatic vitreous floaters. Retina. 2014;34:1055-1061.