Definition

Amblyopia is reduced vision in one or both eyes due to abnormal development of vision in infancy or childhood (1).

There are a variety of factors that lead to amblyopia, both structural (e.g. cataract, droopy eyelid, etc.) and non-structural (e.g. relatively large uncorrected refractive error). Vision loss occurs because the neural pathways between the brain and the eye are not properly stimulated (1). The brain "learns" to see only blurry images with the amblyopic eye. Later on this cannot be improved even when corrective lenses are used. As a result, the brain favors one eye, which is usually due to poorer vision in the fellow eye (1).

Prevalence

Amblyopia affects between 1% and 5% of all children (1), which makes it the most common cause of visual impairment in children and young adults. Occlusion therapy with patching is an effective, well-known, and frequently used therapy (1). Compliance with prescribed patching regimens is the main barrier to successful treatment. Studies demonstrate that only 50% of caregivers achieve the recommended patching times for their children (2).

Importance

Visual acuity, simultaneous use of both eyes (i.e. fusion), and depth perception (i.e. stereopsis) are major parameters measured in determining visual function in the pediatric patient. If a child's visual function is not optimized, his/her learning ability, occupational potential, and psychosocial well-being can be negatively impacted (3, 4). For this reason it is critical that caregivers leave the clinic with clear knowledge of how and why patching is being recommended, along with an understanding of its value (5, 6).

What to Do

A. Instruct caregivers:

1. Where to acquire the patches (including benefits and drawbacks of different types)
2. How to apply the patch
3. How long to maintain the patch each day/week

B. Reinforce the benefits of patching:

1. Provide caregivers with an informational brochure
2. If the child is aged 3 or above, provide an informational cartoon

How to Do It

A. Explain the benefits of patching to caregivers

1. If there is a language barrier, involve an interpreter
2. Work with caregivers to accommodate their need.
   1. We prefer to prescribe patching full-time (i.e. all waking hours). If caregivers feel this is not their preferred treatment, then fewer hours can be prescribed.
   2. If part-time patching is preferred, prescribing a certain number of hours per week and allowing the caregivers to choose the pattern of these hours may improve compliance (6). Caregivers should understand the importance of a routine and a steady effort.  Families are more successful if they have a set number of hours to patch each day with a consistent starting time.
3. Provide informational leaflets to caregivers; these have been shown to increase compliance (7) Important educational information should include:
   1. Instructions about conditioning and reward systems
   2. Instructions about possible complications of patching (e.g. localized skin reactions to adhesives, occlusion amblyopia of the patched eye)
   3. Instructions about the "endpoints" of patching so caregivers understand what they are working toward and when it can be achieved. Our end point of patching is equal vision or 3 patching intervals without improvement (14)

B. Involve the children in their own patching

1. Encourage caregivers to reward children by letting them put a sticker on a calendar for each day they wear the patch (7).
2. Educational cartoons for children have been shown to improve compliance even more so than informational brochures for caregivers (8). This is especially true if there is a language barrier between the caregivers and eye care provider.

C. Utilize a team approach to offer options for patching

1. A Pediatric Eye Disease Investigator Group (PEDIG) study showed that 2 hours of prescribed patching a day led to final visual outcomes that were equivalent to prescribing 6 hours per day; however, compliance was not directly measured in this study (13). Patching for longer periods of time has been shown to lead to faster visual improvement (9).
   1. For this reason, we prescribe full-time patching if possible.
   2. Advantages of full-time patching:
      1. The patient arrives at the end point of patching sooner
      2. The child complains about the patch for fewer days as he/she becomes accustomed to it sooner. This is partially because the vision improves faster but also because the child becomes conditioned to always have a patch on.
2. This allows caregivers (and children, if old enough to participate) to decide which approach will be most tolerable, and thus most likely to be successful. In our experience, most caregivers have remarked that full-time occlusion is easier than part-time, for the reasons stated above.

D. Emphasize all improvements at follow-up appointments

1. It can be discouraging to caregivers if no improvements are seen, as there is often a significant burden to employing occlusion therapy.
2. Any improvements should be explicitly stated; the caregivers and child should be complimented on their efforts.

E. Future directions

1. Smartphone applications to improve compliance (12)
   1. Reminders
   2. Daily check-in with physician office
2. With a dose occlusion monitor (i.e. patch with electrodes and a battery-powered logging unit), personalized patching regimens may be possible.