Weekend Eye Drop Effectively Treats Most Common Eye Disorder of Childhood

Study funded by the National Eye Institute on amblyopia, or lazy eye, the most common cause of visual impairment in childhood, finds that a drop of atropine given 2 days per week works as well as the same drop given 7 days per week. This research finding should lead to better treatment and improved quality of life for children with amblyopia.

Novemeber 1, 2004 -- A study conducted by the Pediatric Eye Disease Investigator Group (PEDIG) has found that a drop of atropine in the unaffected eye of children with moderate amblyopia each weekend day (two days per week) works as well as the same drop given every day. This research finding should lead to better compliance with treatment, more overall improvement in vision, and improved quality of life for children with amblyopia, or lazy eye, the most common cause of visual impairment in childhood. These results appear in the November issue of Ophthalmology. The study was funded by the National Eye Institute of the National Institutes of Health and coordinated by the Jaeb Center for Health Research in Tampa, Florida.

After four months of treatment, children with moderate amblyopia who received the drop of atropine each weekend day to their unaffected eye showed the same improvement in vision as those who received the drop every day. Daily atropine drops as well as placing an opaque adhesive patch over the unaffected eye are considered the standard treatments for moderate amblyopia.

Amblyopia, which usually begins in infancy or childhood, is a condition of poor vision in an otherwise healthy eye because the brain has learned to favor the other eye. Although the eye with amblyopia looks normal, there is interference with normal visual processing that limits the development of a portion of the brain responsible for vision. The most common causes of amblyopia are crossed or wandering eyes or significant differences in refractive error, such as farsightedness or nearsightedness, between the two eyes.

Amblyopia is the most common cause of monocular (one eye) visual impairment among children and young and middle-aged adults.

The daily burden of administering treatment for amblyopia falls on the parent. The findings may make it easier for parents to successfully comply with treatment. Timely and successful treatment for amblyopia in childhood can prevent lifelong visual impairment.

Patching the unaffected eye has been the mainstay of amblyopia treatment. In March 2002, the PEDIG researchers reported that a daily atropine drop was as effective as patching for moderate amblyopia. These eye drops dilate the pupil of the unaffected eye temporarily blurring vision, encouraging the child to use the weaker eye. Both patching and atropine treatments force the child to use the eye with amblyopia, stimulating vision improvement in that eye by helping the part of the brain that manages vision to develop more completely. In 2003 the PEDIG investigators found that 2 hours of patching every day was as effective as 6 hours. These studies together have shown that there are a number of effective treatments for amblyopia. This allows the parents and the eye care provider to select the treatment or perhaps series of treatments that fits best with each patient.

In this study, 168 children less than seven years old with moderate amblyopia were randomly assigned to receive either weekend or daily atropine. The average age of the children was 5.3 years. Patients in both groups showed substantial improvement in the eye with amblyopia, averaging 2.30 lines of improvement following treatment. After four months, 72 percent of children in the weekend group and 73 percent of the patients in the daily group could read at least two more lines on the standard eye chart.

Vision in the unaffected eye decreased by two or more lines in about 2 percent of patients in the weekend group, and about 3 percent of patients in the daily group. Vision in the unaffected eye is expected to return to normal when treatment is completed.

Researchers noted that the amount of vision improvement after four months in the eye with amblyopia should not be considered to be the maximum amount of improvement that can occur with atropine. Fifty-three patients had their study treatment continued beyond 4 months because they had improved, but the acuity was not equal to the unaffected eye. The extended treatment averaged 10 weeks, with an average improvement of 0.8 lines in each treatment group. Sixteen (52%) of the 31 patients in the weekend group and 10 (45%) of the 22 patients in the daily group improved at least one additional line of acuity in the amblyopic eye.

These results do not necessarily apply to all children with amblyopia. Children with more severe amblyopia, older children, and children who have amblyopia from causes other than crossed eyes or refractive error, may need a different treatment regimen. The Pediatric Eye Disease Investigator Group (PEDIG), which conducted this study, conducted a trial of patching in severe amblyopia and found that 6 hours per day produced an improvement that was the same as patching every waking hour each day. The research group is currently conducting a clinical trial on older children with amblyopia as well as a study of patching and eyeglasses and expects the results will be available in 2005.

The Eye Care Center at the Southern California College of Optometry located in Fullerton, CA was one of the 30 PEDIG clinical sites throughout North America that participated in the study. The PEDIG focuses on studies of childhood eye disorders that can be implemented by both university-based and community-based eye care practitioners as part of their routine practice.

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