Broader range of retinal detachments benefit from laser more than surgery

More patients can have demarcation laser photocoagulation as an alternative to retinal detachment surgery.

ByBob Kronemyer

PHILADELPHIA — Demarcation laser photocoagulation is an effective alternative to both observation and surgical repair in select cases of macula-sparing rhegmatogenous retinal detachments (MSRRDs), according to one study.

“Retinal detachments do not need to be small. They can be all different types, sizes and locations,” said Tamara R. Vrabec, MD, an associate surgeon at Wills Eye Hospital and assistant professor of ophthalmology at Thomas Jefferson University here. “The size and location of the detachment, age of the detachment, presence or absence of acute symptoms — none of those appear to be a contraindication to using this technique, so long as the detachment does not involve the focusing point and the detachments are shallow.”

Dr. Vrabec is first author of a retrospective, noncomparative case series of 34 eyes (31 patients) that was recently published in Ophthalmology. In 1997, Dr. Vrabec also published in Ophthalmology results of laser in patients with cytomegalovirus (CMV). “These patients were too ill for surgery, and laser was an alternative. The results were good,” she said. “Based on that success, we expanded our investigation to patients without CMV in certain situations.” Patients with shallow retinal detachments that do not involve the macula and are asymptomatic appear to achieve the best results with demarcation laser photocoagulation.

The authors noted that laser photocoagulation for retinal detachment was introduced back in the 1960s, at which time it was recommended for “limited” retinal detachments defined by size (width at least two times but not greater than five times the diameter of the largest break, and less than 2 clock hours in size with the posterior extent not beyond the equator). “But those investigators did not state whether detachments were acute or chronic, or whether symptoms or demarcation lines were present,” Dr. Vrabec said.

Study parameters

For the current series, the two authors reviewed the clinical records of all patients treated with demarcation laser photocoagulation at their institution between November 1992 and May 1999. MSRRDs were located in all quadrants and affected 10% to 45% of the retina.

Findings associated with MSRRDs included lattice degeneration (12 of 34 eyes), vitreous hemorrhage (four eyes) and demarcation lines (nine eyes). Symptoms (photopsias or floaters) also were associated with 14 MSRRDs. In addition, eight eyes were myopic and 11 were pseudophakic. In total, 32 MSRRDs were shallow, two were dome-shaped and all were smooth without corrugations.

Follow-up ranged from 1.5 months to 80 months (mean 15.8 months; median 17 months). All but one detachment remained stable after laser photocoagulation. The sole patient who had a progression of her retinal detachment 6 weeks after laser treatment “was not considered an appropriate candidate, but she refused the recommended treatment of surgery,” Dr. Vrabec said. For laser, “three rows of confluent laser treatments from ora to ora is necessary. If you do less than three rows — which we had to do for this patient — you can’t expect the treatment to work.”

Encouragingly, three detachments flattened spontaneously after laser. Best corrected visual acuity also was either unchanged or improved by one to four lines (median one line) in all but one eye, in which a cataract developed. “So if patients came in asymptomatic with good visual acuity, then they remained asymptomatic with good visual acuity,” Dr. Vrabec said.

Risks of other options

Surgical repair of MSRRDs has several risks. “These include infection, hemorrhage and blindness, none of which is a risk with laser,” Dr. Vrabec said. In a select subgroup of patients, “I feel that the risks of surgery are greater than the risk of laser.” Likewise, observation for subclinical or asymptomatic rhegmatogenous retinal detachments “has a small risk of progression to retinal detachment, which we did not experience with laser,” she said. Previous studies have documented that even low-risk detachments may progress.

Laser treatment falls about midpoint between observation and surgery. “You are doing something more than observation, but not quite as invasive as surgery,” Dr. Vrabec said. “You avoid some risks, but then again, you give someone a little bit of security against progression. In our follow-up period, there was no evidence of a progression to date.”

For laser to be effective, though, adequate and correctly placed treatment is essential. “Three confluent rows of laser photocoagulation burns in a healthy retina must completely surround the entire detachment and extend to the ora serrata,” Dr. Vrabec said. However, “neither the extent nor the location of the detachment need to be exclusion criteria.” Nonetheless, “detachments in the posterior pole should be treated only if three confluent rows of laser can be placed in the attached retina between the subretinal fluid and the fovea or optic disc without damaging these structures,” she said. Insufficiently confluent or incomplete laser demarcation will likely increase the odds of a breakthrough of subretinal fluid.

“The main reason I will continue to use laser is because it offers a patient a lower risk option. The patient does not have the risk of a serious surgical complication,” Dr. Vrabec said. “If, by chance, the patient progresses or something else occurs, I still have the option of performing surgery.”

For Your Information:

Tamara R. Vrabec, MD, can be reached at Wills Eye Hospital, Retina Service, Second Floor, 900 Walnut St., Philadelphia, PA 19107 U.S.A.; e-mail: trvrdmd@aol.com.

References:

Vrabec TR, Baumal CR. Demarcation laser photocoagulation of selected macula-sparing rhegmatogenous retinal detachments. Ophthalmology. 2000;107:1063-1067.

Vrabec TR. Laser photocoagulation repair of macula-sparing cytomegalovirus-related retinal detachment. Ophthalmology. 1997;104:2062-2067.