New findings from a study published in Ophthalmology evaluated the role of early patching in children with a unilateral congenital cataract (UCC) and whether early visual acuity (VA) measures can predict final visual outcomes.
Give me some background.
The standard of care for children born with a visually significant UCC is early cataract extraction followed by ongoing correction of residual refractive error and part-time occlusion therapy.
Further: To minimize the development of deprivation amblyopia, pediatric patients with unilateral UCC are prescribed occlusion therapy of up to 50% of waking hours with opaque adhesive patches throughout the amblyogenic period.
What has previous data reported on patching for pediatric unilateral UCC?
The Infant Aphakia Treatment Study (IATS) was a multicenter, randomized controlled clinical trial of treatment for UCC that compared visual and adverse outcomes in children receiving an intraocular lens (IOL) at the time of cataract extraction relative to those left aphakic.
The findings: IATS demonstrated that visual acuity (VA) at age 4.5 years was associated with the amount of time that children were patched between 12 and 54 months of age, but this association was not as strong as the link with patching in the first year after surgery.
And what did this mean?
Early patching was determined to be an important predictor of visual outcomes in children born with a UCC, likely because it:
- Establishes enduring patching habits
- Improves visual outcomes, which makes it easier for children to be patched later
I sense a but…
Even so, parents report difficulties maintaining patching regimens, and consistent patching can be challenging for families.
For example: In the IATS, on average, parents reported patching their children fewer than 4 hours per day through the first 54 months of life, even though patching 5-6 hours would be closer to the prescribed 50% of waking hours.
- Moreover: Only 25% of children achieved a VA of 20/40 or better—and 44% had a VA of 20/200 or worse.
Bring it back to this study.
As such: The research team sought to elucidate the extent to which early VA measures are predictive of final visual outcomes and how much patching modifies this association.
The purpose: With this data, parents and providers may better understand at what age patching no longer has benefits for the child and if patching can be safely discontinued.
Got it. Now let’s get into the study.
Investigators analyzed data from the IATS and included 105 children who participated in the IATS and did not have a vision-threatening adverse event.
To evaluate the relationship between VA at age 10.5 years and average daily hours of patching reported by caregivers, the research team reviewed quarterly 48-hour recall interviews and annual 7-day patching diaries obtained between 48 and 60 months of age.
The main outcome measures: Monocular VA was assessed at the clinic visit closest to 48 months of age using the Amblyopia Treatment Study HOTV protocol
- Further: Final VA was measured at age 10.5 years using the electronic Early Treatment of Diabetic Retinopathy Study (ETDRS) testing protocol.
Findings?
Optotype acuity measurements obtained at age 4 years were reliable, with a single-measure intraclass correlation coefficient (ICC) of 0.83 (95% confidence interval [CI] 0.78-0.88), and predictive of those obtained at age 10.5 years (P < 0.01).
- Meaning: ICC is a number between 0 and 1 that refers to correlations within a class of data, and ICC values above 0.8 or 0.9 are regarded as a sign of good or excellent reliability.
Go on …
As such: More than 66% of children remained in the same VA group at age 10, and in 38% (n = 40) of the cohort, the VA measured at age 10.5 years was within ±0.15logMAR (20/25) of the measurement obtained at age 4.
The amount of patching that was received between the fourth and fifth birthdays was unrelated to changes in VA.
Expert opinion?
The study authors reported that in children with good VA, those who had some evidence of stereopsis received less patching than those who were patched more hours per day.
Consequently: “It may be prudent to reduce the amount of time that patching is prescribed for children with near normal VA to maximize the amount of binocular input they experience without compromising their VA,” they stated.
Limitations?
These included:
- A relatively small sample size, particularly in some of the subgroups
- The amount of patching that was prescribed after 5 years of age was left to the discretion of the clinician
- Visual field (VF) testing was not performed, so the potential impact of patching on the expansion of VFs was not measured
- For 10% of children, testers were only somewhat confident or not confident about the VA measurements obtained in the fifth year of life, but testers were very confident in the acuity measurements collected for all children with good vision
- It is unclear what factors, beyond patching, adherence to refractive correction, and age of surgery, determine the final visual outcome for children with a UCC
- While some children were able to complete optotype acuity testing at earlier ages, the research team could not ensure that VA at earlier time points were as stable as VA at or after age 4
Tie it all together for me.
These findings suggest that VA measures obtained early in the fifth year of life are reliable and predictive of final visual outcomes.
Additionally: Less-aggressive patching protocols, or discontinuing patching altogether, may be justified in some children—particularly those with poor vision, once optotype acuity can be measured.
However: The potential impact of latent nystagmus on uniocular VA measurement and the effect of patching on the child’s quality of life, family relationships, and binocular visual field need to be considered before discontinuing occlusion therapy.