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Gradual reductions in the amount of patching from 3 to 4 hours at 1 year of age showed significantly better outcomes in children who undergo unilateral congenital cataract surgery.
Reviewed by Scott R. Lambert, MD
The amount of patching is an important predictive factor of visual outcomes and stereopsis in children who undergo unilateral cataract surgery. Gradual reductions in patching from 3 to 4 hours at 1 year of age showed significantly better outcomes in these patients.
There is no gold standard regarding the amount of patching of the “good eye” in children who underwent removal of a cataractous lens, according to Scott R. Lambert, MD.
“There is a great deal of evidence regarding the amount of patching to use in children with strabismus and esotropic amblyopia from various studies,” said Dr. Lambert, national chairman of the Infant Aphakia Treatment Study (IATS) and professor of ophthalmology, Stanford University Medical Center, Palo Alto, CA. “However, no good studies have provided data on patching children with visual deprivation amblyopia.”
This absence of guidance for this subpopulation of children prompted Dr. Lambert and colleagues to perform an analysis of data from the IATS (JAMA Ophthalmol. 2014;132:676-682), a multicenter clinical trial sponsored by the National Eye Institute that compared visual outcomes after unilateral cataract surgery in children with and without an IOL.
More about the study
The IATS enrolled 57 aphakic infants with contact lens correction and 57 patients with an IOL and spectacle correction. All parents of children in both study arms were instructed to patch the good eye for 1 hour/day per month of age until children were 8 months old, and 50% of the children’s waking hours thereafter until they reached the age of 5 years.
When children were 4.5 years, a masked examiner traveled to each of the study’s clinical sites and tested HOTV acuity and stereopsis using the Randot, Frisby, and Titmus test.
The IATS results indicated that 30 children had 20/40 or better HOTV acuity at 4.5 years of age. Half of these children had a stereopsis response on one or more of the three tests, and the other half did not.
This finding raised the question about the specific differences in their baseline or postoperative factors between these children with good vision in the two groups that resulted in the differences in stereopsis.
Dr. Lambert recounted the results of a study that found that the vision (median vision, 0.90; 20/160 Snellen) in treated eyes of 4.5-year-old children was the same in those treated with a contact lens and those with an IOL.
“While there was a wide range of acuities in both groups, some children in both groups had very good vision,” he said.
These were the patients on whom the investigators focused.
Baseline factors considered were age at cataract surgery, type of cataract, type of insurance (private/public), corneal diameter, axial length, race, and gender, but none was significant.
Postoperative factors examined were visual acuity of the treated eye, type of optical correction, adverse events, additional intraocular surgeries, glaucoma, orthophoria, and strabismus surgery.
Only the last two reached statistical significance (p = 0.003 and p = 0.002, respectively), according to Dr. Lambert.
“This result was not unexpected, because in order to have stereopsis the child would have to have good ocular alignment and good visual acuity,” he said.
Investigators also examined contact lens use by contacting the parents every 3 months to determine the amount of patching and if the children were wearing contact lenses or glasses. A diary also was completed annually.
When children were subdivided by age, no difference was seen in daytime contact lens use, which was adhered to almost 100% of the time, Dr. Lambert noted.
When use of glasses was evaluated among the different age groups, the findings were similar again and no significant differences were identified.
Importance of patching
Patching was the factor that proved to be highly relevant, according to Dr. Lambert.
“We found a significant difference between the two groups in the hours of patching per day,” he said.
“The children without stereopsis were patched more in each age group compared with the children with stereopsis,” he added. “During the first year of life, the children with no stereopsis were patched more than 5 hours a day, while the children with stereopsis were patched about 3.5 hours a day.”
When the children were 4 to 5 years of age, the difference between the groups increased even more. In this age group, the children without stereopsis were patched about 5 hours a day and those with stereopsis were patched less than 2 hours a day.
This finding regarding the beneficial effect of less hours of patching is consistent with a published study (Jeffrey et al. JAAPOS. 2001;5:209-216) that reported better stereopsis or fusion with 25% to 50% patching during waking hours versus 80% patching during waking hours following unilateral cataract surgery.
“It is possible that there is a patching threshold,” Dr. Lambert said. “Exceeding this threshold might not result in improved visual acuity but might impair binocularity.”
Up until 1 year of age, about 3 to 4 hours of patching daily seems adequate to achieve a good visual outcome, he concluded.
The amount of patching can be reduced gradually after 1 year of age if the vision remains good.
Intensive patching might interfere with the development of stereopsis and not improve the visual outcome following unilateral congenital cataract surgery.
“This is important information to give to parents of children with unilateral congenital cataract,” Dr. Lambert said.
Scott R. Lambert, MD
This article was adapted from Dr. Lambert’s presentation at the 2016 meeting of the American Academy of Ophthalmology. Dr. Lambert has no financial interest in any aspect of this study. The study was funded by a grant from the National Eye Institute.