OR WAIT null SECS
Surgeon uses medium-term perfluoro-n-octane without a scleral buckle for inferior, nasal, and temporal giant breaks as well as inferior retinal detachments.
This article was reviewed by Steve Charles, MD
Medium-term perfluo-N-octane (PFO) without a scleral buckle is the preferred treatment of Steve Charles, MD, for inferior, nasal and temporal giant breaks as well as inferior retinal detachments. He uses the PFO after vitrectomy as a tamponade and leaves it in place in eyes completely filled with the substance for 14 days.
According to Dr. Charles, clinical professor ophthalmology, University of Tennessee, Memphis, this approach, which he has used in excess of 1,000 cases over almost 20 years, eliminates the need for postoperative prone or face-down positioning and does not limit the patients’ activities or positioning such as is associated with the use of gas bubbles as a tamponade.
Related: Central subfield thickness only partially responsible for changes in acuity
“I use this for inferior detachments and not for detachments above the horizontal meridian,” he said. “Without the use of scleral buckles, no myopia or strabismus is induced, and there is no pain, ocular surface disorder such as poor conjunctival closure, or corneal damage. This treatment is ideal in phakic and in those with intraocular lenses.”
He also discounted the notion that this tamponade is associated with toxicity.
“In my series of eyes, I have seen no evidence of toxicity associated with the Alcon product which is used off-label,” he stated.
When performing peripheral vitrectomy to repair inferior detachments, Dr. Charles emphasized the importance of removing residual vitreous at the top of the bubble.
“Surgeons must be meticulous about removing vitreous at the point at which the top of the bubble interacts with the superior retina,” he explained. “Don’t be casual about scleral depression and wide-angle visualization to remove superior vitreous.”
Related: Managing irregular cornea with scleral contact lenses
Dr. Charles injects PFO, which was developed by Stanley Chang, MD, to treat giant breaks, using a dual-bore cannula (MedOne Surgical Inc.).
He advises using the following procedure: Keep the tip of the cannula in contact with the initial bubble made over the optic nerve head, carefully focus and follow that bubble upwards as it expands.
“If method is used, a single bubble will result,” he said. “If multiple small bubbles are created, the chances are higher of one of them going through the break and into the subfoveal space.”
Regarding treating retinal breaks with laser, Dr. Charles has always used confluent laser around the breaks.
“You should never apply multiple rows of spots because of the potential for creation of under lapping, over lapping and larger peripheral field defects,” he said.
Dr. Charles also advises draining subretinal fluid if it persists after PFO is injected.
“If the break is carefully cannulated, the subretinal fluid drainage can be initiated,” he said. “Internal drainage techniques can still be used even in the presence of PFO."
Related: AAO 2019: Encouraging results revealed from early trial of subretinal gene therapy for wet AMD
Dr. Charles noted that if this is done carefully, usually going anteriorly can be avoided as the fluid is forced anteriorly. He uses medium term PFO for all inferior, nasal, and temporal giant breaks as well as all inferior retinal detachments.
If the breaks are nasal and temporal, the patients lies on his or her side postoperatively. Dr. Charles emphasized that the cavity is filled with PFO, using less is not as effective. A full fill results in less formation of small bubbles and the advantage, he noted, is that there is no exchange and, therefore, no slippage when managing giant breaks.
“The retina is put back where it belongs,” he said, adding that he has used this technique in pediatric patients with inferotemporal breaks, in whom the PFO was left in the eye for two weeks. In these patients, the lenses remained clear after 15 to 20 years.
An associated point is that vitrectomy does not cause cataracts, vitrectomy causes nuclear sclerotic cataract progression.
“The idea that medium-term PFO should not be used in phakic patients is nonsense,” Dr. Charles stressed.
Related: Pearls for managing tricky cataracts in post-vitrectomy eyes
Removing the PFO in 14 days is mandatory, because of development of a foreign-body reaction in some patients. He uses topical difluprednate twice daily in these cases unless the patient is a steroid responder.
Dr. Charles pointed out that he always excises the anterior flap in giant break cases to avoid its moving forward and causing epiciliary tissue and hypotony.
He again reemphasized the importance of completely filling the eye with PFO.
“To do this carefully in a phakic eye, the contact lens must be removed,” he said. “Go to the highest magnification right behind the lens, and very carefully remove the last layer of subretinal fluid, infusion fluid, and liquid vitreous that floats up to the top of the PFO to achieve a full fill.”
Dr. Charles also advises a PFO/gas exchange or a PFO/silicone oil exchange for a superior giant retinal tear; he uses silicone oil in eyes with proliferative vitreoretinopathy.
“The technique for the exchange is extremely important,” he said.
Related: Case study: Complex retinal detachment in presumed genetic vitreoreinopathy
Under chandelier illumination, the silicone oil injection VFC is held in one hand and the extrusion cannula without a soft tip in the other hand to remove the PFO. Dr. Charles advises not using the soft-tipped cannula on the optic nerve head to avoid slippage; the cannula should be positioned at the top surface of the outer margin of the PFO.
This position at the periphery facilitates skimming off of any aqueous liquid and not PFO at the top surface. In a phakic eye, care must be taken to not touch the lens with the cannula. The surgeon must remain focused on the cannula tip during the exchange posteriorly to get the best view of the interface. This technique allows all the residual fluids to be removed before the PFO.
A novel tamponade
When performing an autologous macular patch graft, Dr. Charles uses a procedure developed by Tamer Mahmoud, MD, PhD, to address a macular hole that is under medium-term PFO. The PFO is removed after seven days. The PFO provides better oxygenation than silicone oil and enables the oxygenation from the anterior surface, not just the choriocapillaris.
Read more by Lynda Charters
Steve Charles, MDE: email@example.com
This article is derived from Dr. Charles' presentation at the Academy of Ophthalmology 2019 annual meeting. Dr. Charles is a consultant to Alcon.