Eye patching for lazy eye: how it works

How patching works

When the stronger eye is covered, the weaker eye has to do the seeing. With regular practice, the brain gets more used to using that eye. The National Eye Institute lists an eye patch over the stronger eye as a standard treatment for lazy eye [1].

Patching is usually used together with glasses, if the child needs them [15]. The glasses correct the focusing problem, and the patch encourages use of the weaker eye.

How long and how often

The NHS describes wearing a patch over the stronger eye for a few hours a day, for several months [15]. The American Academy of Ophthalmology says patching typically lasts several months, and is sometimes part-time for years [16].

The exact plan is your eye doctor's decision. In one large trial of children aged 7 to 17, the prescription was 2 to 6 hours of patching a day, combined with close-up activities [18]. Vision is rechecked at follow-up visits, and the hours are changed if needed.

Patching or atropine drops?

Atropine drops blur the stronger eye, which has a similar effect to a patch. A trial compared the two in 193 children aged 7 to 12 with moderate amblyopia. The children had either weekend atropine or 2 hours of patching a day. After 17 weeks, vision had improved by an average of 7.6 letters with atropine and 8.6 letters with patching. The authors judged the two treatments to be equivalent, and about 1 in 5 children reached 20/25 or better in the weaker eye [17].

Which one suits your child can depend on how well they tolerate a patch, the daily routine and your doctor's advice.

Sticking with it

Patching is hard for many children, and treatment only works if it is done. In the one trial analysed by a Cochrane review, 90% of the children in the patching group completed more than 75% of the prescribed time. In the same trial, only 47% of the children using an iPad game did so [9].

These practical tips are general suggestions, not results from the studies above:

• Fix a routine, such as the same hours each day.
• Match patching time to activities your child enjoys, such as drawing or building. Close-up tasks were part of the trial plan [18].
• Use a simple reward chart and praise effort, not just results.
• Tell your eye doctor early if the patch is not staying on, if the skin is sore, or if your child is very upset. There may be another way to give the treatment.

What patching cannot do

Patching does not always bring vision to 20/20, and it does not teach the two eyes to work together [5]. A Cochrane review notes that fewer than two thirds of children reach good vision in the weaker eye with standard treatment. It also notes that depth perception improves little and that keeping up with treatment is a problem [9]. That is why researchers are testing other approaches, such as dichoptic therapy.

When patching stops

Vision can drop back after treatment is reduced or stopped. In a review of 653 patching trials in 449 children, 27% were followed by a recurrence within a year [19]. A follow-up study of children patched for 6 to 8 hours a day linked tapering treatment gradually with about four times lower odds of recurrence [20]. That study was observational, so ask your doctor how to stop and when to re-check vision.

Questions to ask your eye doctor

• How many hours a day, and for how many weeks?
• Which activities should we do while the patch is on?
• When will you re-check vision, and what result are we aiming for?
• What if the patch is not tolerated? Are drops an option?
• How should we reduce patching when vision improves?

For the wider picture, read our overview of lazy eye treatment.