Stereopsis outcomes for aphakic infants similar with IOL or contact lens correction
Age at the time of surgery and vision in the treated eye influenced outcomes.
Stereopsis outcomes were comparable at 4.5 years of age in infants with unilateral congenital cataract who underwent cataract surgery and optical correction with either a primary IOL or a contact lens in the Infant Aphakia Treatment Study.
“We found that the visual outcomes were the same if an infant was treated with an IOL or a contact lens after unilateral cataract surgery, but the children treated with an IOL had more intraoperative and postoperative adverse events and require more additional intraocular surgeries to treat these adverse events,” study chairman Scott R. Lambert, MD, said.
The stereopsis results, which appeared in the American Journal of Ophthalmology, were based on the study of 114 patients who underwent surgery between 1 month and 7 months after birth and were randomized equally to either an IOL or a contact lens (either a Bausch + Lomb SilSoft or a rigid gas-permeable lens).
A masked examiner evaluated each patient at 4.5 years of age using three tests — the Frisby Stereotest, the Randot Preschool Stereoacuity test and the Titmus Fly test — to assess gross stereopsis.
Twenty-eight patients (25%) had measurable stereopsis with at least one of the three stereopsis tests; however, only about 4% of patients had high-grade stereopsis.
“The children with the best stereopsis [outcomes] had early cataract surgery at 4 to 5 weeks after birth and excellent visual acuity,” Lambert told Ocular Surgery News. “High-grade stereopsis is the hardest visual outcome to achieve in these patients.”
Specifically, 12% of patients showed some stereopsis with the Frisby test, 3.7% with the Randot test and 19.3% with the Titmus test. These results did not differ significantly between the two treatment groups.
Based on the child’s behavior and cooperation, the examiner also assigned a confidence rating for each test: “very confident,” “somewhat confident” or “not confident.” The examiner felt 90% “very confident” using the Frisby test compared with 96% for the Randot test and 93% for the Titmus test.
Visual acuity outcomes
Despite similar outcomes in stereopsis between the two treatment groups, the median age at surgery for patients with stereopsis was younger (1.2 months) than for those without stereopsis (2.4 months). The median visual acuity for patients with stereopsis at 4.5 years was also better (20/40) than for those without stereopsis (20/252).
“I was surprised, though, that some children who had cataract surgery after 6 weeks of age still had good visual outcomes,” Lambert said. “I was also surprised how well some of the children ended up seeing at age 5. In fact, one child was able to see 20/12 in both eyes and had normal stereopsis, showing that it is possible for these children to have normal vision if treated appropriately.”
All four patients who showed a stereopsis response to the Randot test had at least 20/32 visual acuity in the treated eye and underwent surgery before reaching the age of 1.2 months. Visual acuity was 20/40 or better in the eight patients who had positive stereopsis responses to both the Frisby and Titmus tests.
Lambert said he prefers to leave infants aphakic and treat them with contact lenses if parents can afford the lenses and if he feels they can manage contact lenses.
“Otherwise, I would still recommend implanting an IOL, even though significantly more secondary surgeries were performed in patients who received an IOL,” he said.
Lambert has been interested in trying to develop more evidence-based treatments for congenital cataracts since entering the field of pediatric ophthalmology.
“We hope to obtain funding so we can examine these children one additional time, when they are 10 years old,” he said. – by Bob Kronemyer
Reference:Hartmann EE, et al. Am J Ophthalmol. 2015;doi:10.1016/j.ajo.2014.09.028.
For more information:Scott R. Lambert, MD, can be reached at Emory Eye Center, 1365B Clifton Road, Atlanta, GA 30322; 404-778-3709; email: firstname.lastname@example.org.
Disclosure: Lambert has no relevant financial disclosures.