Vitreoretinal Surgery
Perfluorocarbon Liquids in Vitreoretinal Surgery
EDWARD QUINLAN, MD, & JULIA A. HALLER, MD

The use of perfluorocarbon liquids as an intraoperative tool is widely recognized as a significant advancement in the field of vitreoretinal surgery. Stanley Chang, MD, Edward S. Harkness Professor and chairman of Ophthalmology at Columbia University, has been honored for his pioneering work in this area. He published the initial reports of the use of perfluorocarbon fluids in humans in the late 1980s. Dr. Chang demonstrated that their use in complex retinal detachments increased the success rate of retinal reattachment in these cases.

These initial reports concerned retinal detachments associated with proliferative vitreoretinopathy,¹ trauma,² and giant retinal tears.³ The usefulness of perfluorocarbon liquids has led to an expansion in their indications for use and reports have cited their benefit in patients with posteriorly dislocated lenses, submacular hemorrhage, and suprachoroidal hemorrhage. This article will review some of the uses of perfluorocarbon liquids in our practice.

Initially designed for use as a blood substitute due to their high oxygen-carrying capacity, perfluorocarbon fluids have also been investigated for use in liquid ventilation in preterm infants with respiratory complications and in adults with acute respiratory distress syndrome. Perfluorocarbon liquids possess a number of characteristics that make them quite useful in vitreoretinal surgery. They have a high specific gravity (1.6-2.1) relative to saline, which results in their excellent retinal tamponade effect. They have a high interfacial tension that makes them cohesive enough to remain as a single large bubble. They are optically clear fluids with refractive indices only slightly different than saline. This slight difference in refractive index allows for easy visibility of the different fluid interfaces. Their boiling point is greater than saline such that endophotocoagulation can be performed without resulting in intraocular vaporization. And they also have low viscosity (2cSt-3cSt at 25Þ C), allowing for easy injection and removal with microsurgical instruments.

A number of commercial perfluorocarbon liquids are available for use in vitreoretinal surgery. Perfluoro-n-octane (Perfluoron, Alcon, Fort Worth, Texas) and perfluoroperhydrophenanthrene (Vitreon, Vitrophage, Lyons, Ill) are 2 perfluorocarbon liquids that have been tested in separate multicenter clinical trials and have been shown to be safe and effective. In a study in which the 2 were compared to each other, the efficacy in terms of retinal reattachment and final visual outcome was similar; however, postoperative retention was found to be greater in the Vitreon group compared with the Perfluoron group.⁴ Although Perfluoron is the perfluorocarbon liquid most commonly used in the United States, Vitreon is also available and has been used with success.

FOR DIFFICULT REATTACHMENTS

At the Wilmer Eye Institute of Johns Hopkins University, we encounter a number of complicated cases where we routinely use perfluorocarbon fluids, most commonly with recurrent retinal detachments associated with proliferative vitreoretinopathy. These cases require meticulous membrane dissection and occasionally
retinotomy or retinectomy in order to achieve retinal reattachment. The ability of perfluorocarbon fluids to provide retinal tamponade and countertraction significantly improves our ability to repair these complex retinal detachments. In cases with proliferative vitreoretinopathy, we begin with removal of posterior membranes and proceed anteriorly to relieve traction. Perfluorocarbon liquid is then instilled over the optic nerve to flatten the retina. The perfluorocarbon liquid will help to identify residual preretinal or subretinal membranes that appear as persistent traction or elevation of the retina. After removal of all membranes, if the retina does not flatten on the existing scleral buckle, a relaxing retinotomy or retinectomy is performed. Additional perfluorocarbon liquid is instilled to flatten the edge of the retina and to allow for placement of endophotocoagulation along the retinotomy/retinectomy edge.

Subretinal hemorrhage that migrates into the subfoveal space generally results in significantly poor vision. In retinal detachment cases with proliferative vitreoretinopathy where retinectomy is being performed, we have found that an added benefit to perfluorocarbon fluid tamponade of the posterior retina is protection of the subfoveal space should there be significant hemorrhage that may arise from severed retinal vessels or the choroid. In a recent case in which we were performing an inferior retinectomy, an adhesion of the retina to the underlying choroid from prior endophotocoagulation was disrupted, resulting in a focal site of choroidal hemorrhage that pooled in the subretinal space. Fortunately, there was perfluorocarbon liquid tamponading the macular region that did not allow the subretinal hemorrhage to migrate into the subfoveal space. After a short period of intraocular pressure elevation, the hemorrhaging subsided and the majority of the subretinal blood was evacuated using a soft-tipped extrusion cannula. There remained a small crescent of subretinal hemorrhage in the temporal macular region; however, no blood reached the subfoveal space.

REMOVING TRAPPED SILICONE OIL

Perfluorocarbon fluids may also be useful in the rare case where silicone oil migrates into the subretinal space. Some weeks following a scleral buckling procedure combined with vitrectomy in which silicone oil was used for postoperative tamponade, silicone oil migrated into the subretinal space through a large open break posterior to the buckle. The break opened and expanded due to contraction of epiretinal proliferation. When the silicone oil was removed from the vitreous cavity at the beginning of the case, the retinal detachment became more bullous and the silicone oil remained entrapped in the bullously detached retina. Perfluorocarbon fluid was instilled over the optic nerve, pushing the subretinal fluid and eventually the silicone oil globule through the open break. The epiretinal proliferation was removed and the retina settled nicely into place, allowing laser retinopexy to be applied around the break. The need for a large retinectomy to remove the silicone oil from the subretinal space was avoided.

STABILIZING RETINA

Patients with proliferative diabetic retinopathy and marked fibrovascular proliferation provide another setting in which perfluorocarbon fluids may be highly useful. This is especially true when the fibrovascular proliferation extends peripherally and involves areas of atrophic retina. Even with careful segmentation and delamination techniques in these cases, retinal breaks may develop due to the atrophic nature of the retina. In this setting, the retina may start to become bullously elevated due to increasing fluid passing into the subretinal space. This makes further membrane removal difficult.

Perfluorocarbon fluid instilled over the macular region will stabilize the retina. It will also provide countertraction that assists with fibrovascular proliferation removal. We find that it is imperative in these cases to relieve traction on posterior breaks before infusing the Perfluoron and to infuse it only in limited quantity and quite cautiously to avoid subretinal migration of the heavy liquid.

FOR LESS COMPLEX CASES

In addition to their utility in complex vitreoretinal cases, perfluorocarbon fluids can also be quite useful in more standard cases. In selected cases of primary vitrectomy for retinal detachment, the use of perfluorocarbon liquids has virtually eliminated the need for a posterior drainage retinotomy. After performing a meticulous vitrectomy, perfluorocarbon fluid is instilled into the eye. This will displace the subretinal fluid anteriorly through peripheral breaks. The perfluorocarbon fluid is instilled up to the posterior edge of the most posterior peripheral retinal break. The retina anterior to the perfluorocarbon generally remains elevated. A fluid/air exchange is performed, removing the aqueous layer first and aspirating subretinal fluid through the peripheral breaks, resulting in flattening of the anterior retina. Once all of the aqueous fluid has been removed, the perfluorocarbon fluid is subsequently removed. Endophotocoagulation can then be applied to create a chorioretinal adhesion around the retinal breaks.

CONCLUSION

Since their introduction in the 1980s, perfluorocarbon liquids have revolutionized vitreoretinal surgery. They have improved surgical outcomes in complex retinal detachments as well as routine cases and have resulted in shortened operating times. Perfluorocarbon liquids remain an invaluable tool for the vitreoretinal surgeon. RP

REFERENCES

1. Chang S, Ozmert E, Zimmerman NJ. Intraoperative perfluorocarbon liquids in the management of proliferative vitreoretinopathy. American Journal of Ophthalmology. 1988;106: 668-674.

2. Chang S, Reppucci V, Zimmerman NJ, Heinemann MH, Coleman DJ. Perfluorocarbon liquids in the management of traumatic retinal detachments. Ophthalmology. 1989;96:785-91.

3. Chang, S, Lincoff H, Zimmerman NJ, Fuchs W. Giant retinal tears. surgical techniques and results using perfluorocarbon liquids. Arch Ophthalmol. 1989;107:761-766.

4. Loewenstein A, Humayun MS, de Juan E Jr, Campochiaro PA, Haller JA. Perfluoroperhydrophenanthrene versus perfluoro-n-octane in vitreoretinal surgery.Ophthalmology. 2000;107:107-1082.

Edward Quinlan, MD, and Julia A. Haller, MD, are retina specialists at the Wilmer Eye Institute of Johns Hopkins University. Dr. Quinlan may be reached via e-mail at equinlan@jhmi.edu. The authors have no financial interest in any of the products mentioned in the article.