Ophthalmology News
July 2008
by Rich Daly
EyeWorld Contributing Editor
Study finds the approach avoids significant complications that could compromise the visual prognosis of these patients
An alternative approach to control bleeding after primary diabetic vitrectomy was bolstered by recent research that found anatomic success and functional stability among patients who received it.
Prolonged silicone oil tamponade was used after primary diabetic vitrectomy instead of gas in a study published in the November-December 2007 issue of the European Journal of Ophthalmology. The study, titled “Extended silicone oil tamponade in primary vitrectomy for complex retinal detachment in proliferative diabetic retinopathy: A long-term follow-up study,” found the approach avoided significant complications that could have compromised the patients’ visual prognosis.
Yun-Dun Shen, M.D., Department of Ophthalmology, Changhua Christian Hospital, Changhua, Taiwan, and colleagues studied the long-term anatomic and functional results of extended silicone oil tamponade among these patients from January 1999 to June 2005. They performed a retrospective review of the clinical records of consecutive patients who underwent primary vitrectomy with extended silicone oil tamponade for complex retinal detachment.
Among the 54 eyes of 45 patients (18 male, 27 female) that were included in the study, all underwent at least 12 months of follow up.
The authors found anatomic success in 85% at the third month post-op and 83% percent success at the last follow-up exam. Best-corrected visual acuity (BCVA) improved or remained unchanged in 89% at the third month post-op and in 78% at the last follow-up exam. Ambulatory vision was achieved in 41% of patients at the third month post-op and in 44% at the last follow-up exam. Pre-op BCVA was identified as the only variable statistically associated with final BCVA.
The investigators found that the post-op complications included peri-silicone oil proliferation in four eyes, neovascular glaucoma in four eyes, oil migration into anterior chamber in nine eyes, and papillary block-induced IOP elevation in five eyes.
The study findings appear to echo the clinical experience of Christina J. Flaxel, M.D., associate professor of ophthalmology, Doheny Retina Institute, Doheny Eye Institute, Los Angeles. She received training in the use of silicone oil during fellowship training in the U.K. and has used it in about 500 such cases over 15 years.
“The benefit of silicone oil in these situations is it usually controls bleeding, and the patient can see through the oil while the retina is stabilized, and it doesn’t require as stringent positioning as gas does,” Dr. Flaxel said.
She has found that the advantages of silicone oil over gas in these patients include the ability to takes flights or travel at high altitude, minimal required follow up, and the ability to see through the oil to some extent. The disadvantages include a need for another surgery to remove the oil, elevated IOP due to oil emulsion, and corneal decompensation if the eye is aphakic and sometimes pseudophakic. Extreme complications include extensive bleeding under the oil leading to massively elevated IOP, which requires surgery to remove the blood and—sometimes—the oil.
Dr. Flaxel noted that the complications identified by the study authors can be difficult to manage. She aims to keep the eye phakic to keep oil from migrating into the anterior chamber. If that is not possible, then Dr. Flaxel performs an inferior peripheral iridectomy (PI) and fills the anterior chamber with air at the end of the case through the PI rather than through a paracentesis.
“I do not have problems with papillary block as long as I have done an inferior PI,” Dr. Flaxel said.
When used, silicone oil is usually left in retinal detachment cases for three months. Dr. Flaxel generally leaves it in diabetic eyes and eyes with macular hole for at least six weeks.
Dr. Flaxel noted that posterior staphylomas in eyes with long axial lengths are difficult to tamponade with oil or gas, though it can be done. She prefers gas in such cases because gas seems to work better in macular hole cases. In myopic detachment cases, Dr. Flaxel has used oil with as much success as gas.
The study investigators’ finding that previous vitrectomy and previous scleral buckling procedures appeared to affect the success of the silicone oil procedure did not fit with Dr. Flaxel’s experience. However, the finding that surgical success in these cases is also impacted by the duration of silicone oil tamponade is probably important, but it did not specifically address the as-yet unanswered question of what the minimum time is that the oil should stay in the eye.
Editors’ note
Dr. Flaxel has no financial interests related to her comments.
Contact Information
Flaxel: flaxelc@ohsu.edu
