Retina Roundup

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, 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, the difference disappeared. The authors found that the changes in choroidal thickness positively correlated with age and negatively correlated with height, thus probably linked to general circulatory factors.

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 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.

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 the predictability of the parameter.

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 predicted retinal thickness on SD-OCT with intraclass correlation coefficients >0.88 μm. In 60% of eyes, the predicted measurement and actual measurement differed by 5 µm or less. While the authors cited the standard study limitations inherent in investigating healthy volunteers, they concluded it is possible to predict SD-OCT data mathematically on the basis of TD-OCT data.

LUCIDATE data

The one-year data from the LUCIDATE trial, conducted in London to compare ranibizumab (Lucentis, Genentech, South San Francisco, Calif.) to laser in treating 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. Investigators 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.

Macular edema following PRP

Because macular edema remains a risk following panretinal photocoagulation (PRP), 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 strongly associated with post-PRP macular edema. Two of 97 eyes without cystoid spaces developed edema.

While they acknowledged the limitations of a retrospective study, the authors suggested SD-OCT could help determine before PRP whether a greater-than-normal risk exists for post-PRP macular edema. OM