THE LATEST PUBLISHED RESEARCH

IVTA for Refractory DME: Two-Year Results
Researchers in Australia reported two-year results from a prospective, double-masked, placebo-controlled, randomized clinical study of intravitreal triamcinolone acetonide (IVTA) for diabetic macular edema and impaired vision that persisted or recurred after treatment with laser. Of the 69 eyes of 43 patients in the study, 34 were randomized to receive active treatment (4 mg/0.1 mL IVTA) and 35 were randomized to receive placebo.

Mean baseline visual acuity was 20/60 in both groups. Patients in the treatment group received an IVTA injection at baseline. Retreatment was considered at each visit provided treatments were at least six months apart. Eyes with a decrease in visual acuity of five or more letters from previous peak level and persistent central macular thickness of more than 250 µm were retreated with IVTA. If visual acuity did not improve by five or more letters four weeks later and macular thickening persisted, patients received additional laser treatment if the investigator thought it would be beneficial. Eyes treated with placebo or eyes in which IVTA was not effective received laser treatment when appropriate.

Two-year data were available for 60 of 69 (87 percent) eyes. IVTA-treated eyes received significantly more treatments with study drug than eyes receiving placebo (mean 2.6 vs. 1.8). However, only one eye treated with IVTA vs. 16 eyes treated with placebo needed further laser treatment (p=0.0001).

In 19 of 34 (56 percent) eyes treated with IVTA, best-corrected logMAR visual acuity improved by five or more letters compared with nine of 35 (26 percent) eyes receiving placebo (p=0.006). Mean visual acuity improvement was 5.7 letters more in the IVTA group.

The study authors reported that cataract progression and intraocular pressure increase were common but manageable. Two eyes treated with IVTA underwent trabeculectomy. One case of infectious endophthalmitis occurred in the treatment group.

Source: Gillies MC, Sutter FKP, Simpson JM, et al. Intravitreal triamcinolone for refractory diabetic macular edema: Two-year results of a double-masked, placebo-controlled, randomized clinical trial. Ophthalmology 2006;113:1533-1538.

Patient Perceptions of IVTA
In response to a telephone survey, patients who had undergone IVTA injection reported no significant difference between pre- and post-injection ocular pain. Fifty patients treated between June 2003 and February 2005 answered questions on a 1 to 5 scale 10 to 12 weeks after injection. The level of pain they expected (2.9) was higher than the actual pain level they said they experienced (1.6; p<.001). They also reported that their vision improved from 2.7 to 3.7 (p<.001). Sixty percent of the patients said their vision improved, and 40 percent said they experienced no change. Sixty-six percent said their vision improved more than they had expected it to improve.

Sources: Roth DB, Scott IU, Gulati N, Prenner J. Patient perceptions of discomfort and changes in vision and functional status associated with intravitreal triamcinolone injection. Am J Ophthalmol 2006;142(3):492-494.

Complement Factor H Gene Associated with Geographic Atrophy
According to the results of a retrospective case-control study, the rs1061170 single-nucleotide polymorphism of the complement factor H gene increases the risk of developing geographic atrophy in addition to increasing the risk of developing neovascular age-related macular degeneration (AMD). The data set for the study consisted of 647 AMD cases (grades 3, 4 or 5) and 163 controls (grades 1 or 2). Each grade was independently compared with the controls, and odds ratios were determined using logistic regression models. A significant association with AMD was found when grades 3, 4 and 5 were compared with controls. The highest odds ratio (3.217) was found when the grade 4 cases were compared with the grade 1 controls (p<0.0001).

Source: Postel EA, Agarwal A, Caldwell J, et al. Complement factor H increases risk for atrophic age-related macular degeneration. Ophthalmology 2006;113:1504-1507.

Focal Laser for RAP
The results of a retrospective, interventional case series indicated that focal laser photocoagulation may be a safe way to manage leakage from retinal angiomatous proliferation (RAP) lesions in patients with AMD. Investigators identified 16 consecutive eyes of 15 patients with AMD and leakage from a stage 1 or stage 2 RAP lesion. High-speed indocyanine green imaging was used to identify the intraretinal component of the lesions, which were treated with a green or yellow wavelength laser to completely ablate the intraretinal component. The subretinal component of stage 2 lesions was not treated.

Early-phase fluorescein angiography shows intraretinal hemorrhage (arrow) in a patient with retinal angiomatous proliferation and 20/60 visual acuity. A horizontal OCT scan shows cystoid macular edema and serous pigment epithelial detachment. (Image courtesy of T. Mark Johnson, MD.) Six months following focal laser application to the retinal angiomatous proliferation lesion, the patient's visual acuity is 20/25. The late-frame fluorescein angiogram shows no evidence of leakage, and the horizontal OCT scan shows resolution of cystoid macular edema and pigment epithelial detachment. (Image courtesy of T. Mark Johnson, MD.)

Mean follow-up time was 15.5 months. Ablation was successful in all eyes (mean number of treatment sessions 1.9). Visual acuity stabilized or improved in 94 percent of eyes. Six percent of eyes lost three or more lines. Retinal edema and subretinal fluid decreased in 87.5 percent of eyes and completely resolved in 69 percent. Fourteen percent of the eyes progressed to retinal choroidal anastomoses.

The investigators reported that treating only the intraretinal component of the lesion might be adequate for controlling leakage and that visual acuity results were better for patients with early-stage lesions.

Source: Johnson TM, Glaser BM. Focal laser ablation of retinal angiomatous proliferation. Retina 2006;26(7):765-772.

Modified PDT for CNV in Pathologic Myopia
Hypothesizing that subthreshold activation of verteporfin might be inadvertently occurring with standard photodynamic therapy (PDT) in highly myopic eyes because of their axial length, investigators compared standard PDT with a twofold illumination regimen for treating choroidal neovascularization (CNV) in patients with pathologic myopia.

They randomized 16 patients with subfoveal CNV caused by pathologic myopia 1:1 to receive either standard PDT (50 J/cm2) or twofold illumination PDT (50 plus 50 J/cm2). The patients had best-corrected visual acuity (BCVA) of 20/320 or better at baseline. If fluorescein angiography showed leakage at week 12, patients received an additional treatment as assigned at baseline.

At the end of the 24-week study period, median change in BCVA from baseline was +0.5 lines for patients undergoing standard PDT and + 2.4 lines for patients undergoing the twofold illumination regimen. An additional PDT session was performed in seven of eight patients assigned to standard PDT and in four of eight patients assigned to the modified regimen.

The investigators reported that larger studies of the twofold illumination regimen with longer follow-up times are warranted.

Source: Costa RA, Williams GA, for the Twofold Illumination Scheme for Photodynamic Therapy Study Group. Twofold illumination photodynamic therapy scheme for subfoveal choroidal neovascularization in pathologic myopia: Results from a randomized pilot study. Retina 2006;26:757-764.

20-Ga. vs. 25-Ga. Vitrectomy for Macular Pucker
The results of a prospective, randomized clinical study involving 67 eyes of 67 patients suggest that vision recovers more quickly after 25-ga. vitrectomy (control group) than after 20-ga. vitrectomy for macular pucker. In the 20-ga. group, mean logMAR BCVA was 20/78 at baseline, 20/62 at one month, and 20/42 at six months. In the 25-ga. group, mean logMAR BCVA was 20/85 at baseline, 20/45 at one month, and 20/40 at six months.

There was a significant difference (p<.001) in change in BCVA between the two groups at one month (-0.10 in the 20-ga. group compared with -0.269 in the 25-ga. group). The difference in BCVA was not significant (p>.01) at six months (-0.327 in the 20-ga. group compared with
-0.276 in the 25-ga. group).

Source: Kadonosono K, Yamakawa T, Uchio E, et al. Comparison of visual function after epiretinal membrane removal by 20-gauge and 25-gauge vitrectomy. Am J Ophthalmol 2006;142:513-515.

Randomized Study of Radiotherapy Plus TTT for Large Uveal Melanomas
Results of the first prospective, randomized study comparing proton beam radiotherapy alone and combined with transpupillary thermotherapy (TTT) for large uveal melanomas were recently published. One half of the 151 patients treated with radiotherapy between February 1999 and April 2003 for melanomas 7 mm thick or 15 mm in diameter received radiotherapy alone (60 Gy in 4 fractions); the other half received the same dose of radiotherapy followed by TTT at one, six and 12 months.

Median follow-up was 38 months. Patients treated with TTT had a greater reduction of tumor thickness (p=0.06), less retinal detachment at the latest follow-up (p=0.14), and a lower secondary enucleation rate (p=0.02).

The investigators recommended that further studies be performed to test the combined treatment in smaller tumors and to determine the optimal dose.

Source: Desjardins L, Lumbroso-Le Rouic L, Levy-Gabriel C, et al. Combined proton beam radiotherapy and transpupillary thermotherapy for large uveal melanomas: a randomized study of 151 patients. Ophthalmic Research 2006;38:255-260.