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Induced PVD by gas injection may slow diabetic retinopathy
Mexican study of 12 patients with 2-year follow up shows “promising” future for this treatment.
MEXICO CITY — Results from a 2-year follow-up of patients with nonproliferative diabetic retinopathy suggest intravitreal sulfur hexafluoride injection to induce posterior vitreous detachment may slow the progression of the eye disease.
However, researchers strongly caution that the study of 12 patients is too small to make definite conclusions regarding a correlation between induced posterior vitreous detachment (PVD) and progression of diabetic retinopathy.
The study
Primary investigator Daniel Ochoa-Contreras, MD, of the Association to Prevent Blindness in Mexico, and colleagues injected an intravitreal gas bubble of sulfur hexafluoride (SF6) via the pars plana into one eye of 12 patients with nonproliferative diabetic retinopathy (NPDR). The fellow eye was used as control. After 24 months of follow-up, the gas-injected eye remained stable without progression of the retinopathy, whereas more than half of the 12 eyes in the control group progressed to proliferative retinopathy or to more severe stages of nonproliferative retinopathy.
“We cannot be certain the patients would not have experienced a similar result without the procedure — that is, we do not know for certain that it was the gas injection that is responsible for the different course in one eye compared with the control eye,” Dr. Ochoa-Contreras said. He added that they have now performed the procedure in more patients, and the results are promising.
“Our main concerns and objectives were that such treatment was not dangerous or threatening to the eye, was in expensive so patients in Third World countries could have access to it and was effective in preventing progression to more advanced stages of the disease,” he said.
Intravitreal SF6
Intravitreal SF6 is widely used in the treatment of selected cases of retinal de-tachment, but Dr. Ochoa-Contreras’ study marks the first long-term follow-up of SF6 to cause PVD in patients with bilateral NPDR. The findings were published in Acta Ophthalmologica Scandinavica.
After receiving 2 cc of peribulbar lidocaine, patients were injected with 0.5 cc of SF6 at the consult office. Patients used topical antibiotic drops four times a day over the next 5 days. Patients were examined the following day and weekly for the next month. After 4 weeks, PVD was detected in all gas-injected eyes. No peripheral lesions or progression of retinopathy have been detected to date.
The gas-injected eyes were compared to the fellow eyes of the same group of patients, left untreated serving as the control group. At the 2-year mark, two eyes (16.6%) in the control group progressed to PDR, and five eyes (41.6%) progressed to more severe stages of NPDR. The other five eyes remained stable.
Akira Hirata, MD, an ophthalmologist at the Kumamoto University School of Medicine, Japan, said he has witnessed PVD after SF6 or perfluoropropane injections during the treatment of eyes with subretinal hemorrhage developing from age-related macular degeneration. He added, however, that he is unsure whether induced PVD for NPDR is necessary because of an increased risk of vitreous hemorrhage, retinal tear, rhegmatogenous retinal detachment and gas-induced cataracts.
“If there is no backup system for treating such complications, we need to carefully discuss this with patients before performing the prophylactic technique,” Dr. Hirata said.
For Your Information:
- Daniel Ochoa-Contreras, MD, can be reached at the Asociacion Para Evitar La Ceguera en Mexico, Mexico City, Mexico; +(52) 5-659-3597, ext. 51; fax: +(52) 5-659-5928; e-mail: retinamex@yahoo.com.
- Akira Hirata, MD, can be reached at Department of Ophthalmology, Kumamoto University School of Medicine, 1-1-1 Honjo, Kumamoto, Japan; +(81) 96-373-5247; fax: +(81) 96-373-5249.
Reference:
- Delsol-Coronado L, Quiroz-Mercado H, et al. Induced posterior vitreous detachment by intravitreal sulfur hexafluoride (SF6) injection in patients with nonproliferative diabetic retinopathy. Acta Ophthalmologica Scandinavica. 2000;78:687-688.