AAPOS offers information on ROP incidence, IOL implantation

Highlights include a report on a 5-fold increase in IOL implantation.

WAIKOLOA, Hawaii — Several hundred pediatric and general ophthalmologists enjoyed education in paradise here at the annual meeting of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS). Topics included retinopathy of prematurity (ROP), treatment of esotropia and IOL implantation.

One physician in particular presented on an increase in use of IOLs in pediatric cataract surgery. According to M. Edward Wilson, MD, and colleages, pediatric ophthalmologists are implanting IOLs at five times the rate they were in 1993, according to a survey of AAPOS members.

The 2001 survey reported an increase in IOL implantations in children under age 2. The AAPOS Pediatric Cataract Surgery and Intraocular Lens Implantation Survey was described in a poster presentation here.

Dr. Wilson found that as implantation rates increased, the minimum age for unilateral implantation dropped from 4 years in 1993 to 1 year in 2001.

Similarly, in 1993, the minimum age for bilateral IOL implantation was 7 years. In 2001, the minimum age had dropped to 2 years.

Twenty-eight percent of the 402 AAPOS members who responded to the survey said they do not perform pediatric cataract surgery. Of surgeons who perform pediatric cataract surgery, 61% used a manual anterior approach, and 11% used a manual posterior approach. Of the respondents, 85% said they would not consider an anterior chamber IOL for a young child.

Early curtailment of oxygen therapy lowers incidence of ROP

In topics regarding ROP, Kenneth W. Wright, MD, presented on how the incidence of severe ROP in low birth weight and premature infants significantly decreased after surgeons reduced the use of oxygen therapy.

“Before the early curtailment of oxygen supplements to premature babies, our center had a high incidence of severe retinopathy of prematurity (ROP),” Dr. Wright said here.

In March 1998, researchers at Cedars-Sinai Medical Center in Los Angeles implemented a new oxygen protocol for infants weighing less than 1,500 g. Dr. Wright and colleagues performed a retrospective study comparing the outcomes of infants’ ROP and threshold ROP before and after the new oxygen protocol.

“We evaluated the charts of 80 patients before the new protocol and 221 patients after the new protocol,” Dr. Wright said. “After the new therapy, ROP significantly decreased.” He noted a significant decrease in the incidence of stage 3 and stage 4 ROP was seen from 1999 to 2001 (P = .0118). A significant decrease in the incidence of laser therapy use for threshold ROP was also noted (P = .006).

While a decrease of oxygen therapy in premature infants has been shown to increase mortality rates, Dr. Wright said that infant survival at his center improved slightly after the new oxygen protocol. The new protocol resulted in a survival rate of 89%, compared with 80% with the previous protocol.

Near-confluent laser photocoagulation effective

Near-confluent laser photocoagulation produced excellent visual acuity results in children with severe retinopathy of prematurity, according to a study.

Researchers from the Department of Ophthalmology, Alberta Children’s Hospital, Canada, retrospectively reviewed the charts of 42 patients treated with near-confluent diode laser photocoagulation for severe ROP.

Near-confluent diode laser photocoagulation was defined as laser therapy with no greater than half the width of space between burns. Researchers presented results in a poster.

Study participants were between 31 and 133 days old during the time of the surgeries, which occurred between 1995 and 2001. Patients who had zone 1 ROP had earlier values for their chronological age and post-conceptional age.

Twenty-four males and 18 females underwent the procedure. The mean birth weight of patients was 756 g, with a range of 471 to 1240 g. Mean follow-up period for patients was 37 months. The postoperative visual acuity of patients was 20/30.3, with a spherical equivalent of –2.41 D.

While results were positive, strabismus occurred in 30% of patients, the authors wrote.

Botulinum toxin successful treats patients with small angle esotropia

A long-term study found botulinum toxin to be a successful and well-tolerated therapy for small angle esotropia, according to a poster presentation.

Emma L.M. Dawson, DBO, and researchers at Moorfields Eye Hospital, London, retrospectively reviewed the hospital’s toxin clinic database over an 18-year period. They identified 68 patients (47 females and 21 males) with esotropia who were treated with prisms under 20 D. Patients averaged 34 years of age during treatment.

Forty-seven percent (n = 32) of patients had residual esotropia, while 29% (n = 20) had primary esotropia. Of the remaining patients, 16% had consecutive esotropia, 6% had secondary esotropia, and 1.5% had decompensating esophoria. Patients received an average of six injections of botulinum toxin (Novartis).

Of all patients, 66% underwent continued toxin treatment at an interval of 3 to 31 months, while 19% of patients benefited from just one injection, with long-term results.

Following initial injections, 13% of patients required surgery. Seven patients unable to demonstrate binocular vision before injections gained binocular vision after botulinum toxin therapy.

AcrySof foldable lens safe, effective for secondary pediatric IOL implantation

Alcon’s AcrySof foldable lens was found to be safe and effective in treating aphakic pediatric patients who underwent secondary IOL implantation, according to a study.

“This is really the first study of its kind,” Tracy C. Crnic-Rein, MD, told attendees of the annual meeting of the American Association for Pediatric Ophthalmology and Strabismus. Dr. Crnic-Rein said previous studies on secondary pediatric IOL implantation reported good results with rigid IOLs. However, Dr. Crnic-Rein said no study has accessed the safety and efficacy of soft, foldable and injectable IOLs for the procedure.

This study reviewed the records of 55 eyes of 36 patients with a minimum of 6 months’ follow-up. “All children had congenital or developmental cataract, and many had no contact lens compliance,” Dr. Crnic-Rein said. Records were analyzed for the age of the child at surgery, preoperative and postoperative refraction and visual acuity, anisometropia and complications.

“Since most children had poor vision prior to the procedure, we looked to see if there was a visual acuity change, rather than an improvement in visual acuity,” Dr. Crnic-Rein said.

Outcomes showed 7% of patients lost 3 lines of visual acuity. The mean postop refractive error of all patients was –0.1 D (SD 3.2 D); anisotropia was 2.01 D.

Opacification of the visual axis after cataract surgery in the first year of life occurs more frequently when ocular abnormalities are present, according to one surgeon.

Visual axis opacification after cataract surgery increases with ocular abnormalities

“Postoperative opacification was most common in patients with anterior segment dysgenesis and persistent fetal vasculature,” Rupal H. Trivedi, MD, said here.

Dr. Trivedi retrospectively reviewed the charts of 64 eyes that underwent cataract surgery and acrylic IOL implantation during the child’s first year of life. Of those eyes studied, 27 eyes underwent a single acrylic IOL implantation. “All eyes had primary posterior capsulectomy and anterior vitrectomy,” Dr. Trivedi said.

One-third of the patients who developed postoperative opacification required a secondary surgical intervention at a mean of 5 months. The mean age of patients whose eyes opacified was 3.8 months, compared with a mean age of 5 months for patients whose visual axis remained clear for a longer duration.

“Of those eyes operated on before 6 months of age, 43.7% opacified. Just 18.2% of patients older than 6 months during the time of surgery experienced visual axis opacification,” Dr. Trivedi said.

Opacification was most significantly due to dysgenesis and persistent fetal vasculature. Other factors, such as microcornea, continuity of rhexis and in-the-bag fixation were not found to significantly influence the development of opacification, Dr. Trivedi said.