PEDIG data: Patching reaches target visual acuity quicker than atropine

Patching was also associated with better visual acuity outcomes. Experts say the key to amblyopia management is customization for each patient.

Newly released data from the Pediatric Eye Disease Investigator Group showed that while atropine may be comparable to patching for moderate amblyopia, penalization takes significantly longer to achieve target visual acuity.

In a journal article published in Ophthalmology, PEDIG concluded that both patching and atropine benefit children ages 3 to 7 with a visual acuity range of 20/40 to 20/100.

However, visual improvement is significantly more rapid in children with amblyopia who have visual acuities of 20/80 to 20/100 who were aggressively patched than those who were treated with atropine, according to the study. The study said that after 6 months, the amount of improvement was not related to the number of patching hours prescribed.

The study also showed that 56% of patients who were patched reached the study’s target visual acuity of 20/30 at 5 weeks, whereas only 33% of patients on atropine achieved 20/30 at 5 weeks (P = .001).

Longer treatment not desired

“The authors gloss over the difference by stating the results even out by the 6-month examination. However, this unduly minimizes the importance of this issue,” Burton J. Kushner, MD, wrote in an accompanying editorial for the study.

Dr. Kushner’s comments point to the clinical and practical advantages of an amblyopic patient being treated in 5 weeks as opposed to 6 months.

“The difference between a patient being cured of amblyopia after 6 months of treatment, versus only 5 weeks, can mean a difference of four or five additional trips to the doctor’s office,” Dr. Kushner wrote. “This translates to more time off work, more inconvenience, greater expense, a prolongation of the difficulties that may be encountered with treatment, and more frustration for parent and child.”

Robert S. Gold, MD, Ocular Surgery News Pediatrics/Strabismus section editor, agreed with Dr. Kushner’s statement. “The faster you get this done the better. If a patient reaches your goals after 5 weeks, your future treatment course is made easier. It just makes more sense to go with an effective therapy that gets results quicker. In my practice, patching is still preferred 10 to 1.”

Study, re-examination of data

The recent data released by PEDIG come on the heels of the group’s other studies, which solidified the 30-year-old penalization method as a comparable treatment to occlusion in young patients with moderate amblyopia.

In 2002, PEDIG published “A randomized trial of atropine versus patching for treatment of moderate amblyopia” in Archives of Ophthalmology. This study presented 6-month data from 419 children at 47 U.S. clinical sites. The study concluded that atropine and patching drew comparable scores in visual improvement. However, the study noted that there was a greater and faster initial improvement in the patching group throughout the follow-up period up to 6 months.

In the newly released study, investigators further examined this outcome in the same cohort and determined quicker improvement was present up to 6 months in patched patients with greater numbers of patching (10 hours or more per day) and vision of 20/80 to 20/100. After 6 months, visual acuity was similar in both groups; however, there was a slightly greater improvement in baseline visual acuity at all levels in the patching group. No factors associated with age, depth of amblyopia or cause of amblyopia influenced treatment in either group.

The study authors set aside these findings for atropine by noting that it was consistently the favored method of treatment throughout both studies. In follow-up questionnaires, parents and children favored atropine “hands down” for easier compliance and lack of social stigma associated with the patch.

Better VA for patching

In his editorial, however, Dr. Kushner takes issue with the survey, which was taken by uninformed parents, he said.

“I wonder how many parents who preferred atropine in the survey used in these studies would have voted differently had they been aware of the relative disadvantages of atropine?” he wrote.

According to Dr. Kushner, the majority of parents may have changed their minds had they been aware of the most recent findings that say patching works quicker.

Dr. Kushner also questioned the target visual acuity for the 6-month follow-up results of the studies. Target visual acuity was 20/30 in the study, as opposed to 20/25 or 20/20.

“Had the authors chosen a higher level of visual acuity as their criteria for success, patching clearly would have produced better results,” he wrote. According to Dr. Kushner, 40% of patients in the patching group achieved a final visual acuity of 20/25 or better, while just 28% of atropine patients achieved 20/25 or better (P = .01).

“This is an interesting observation,” Dr. Gold said in an interview with Ocular Surgery News. “Study authors don’t explain why criteria for success was 20/30 vision instead of 20/20 or 20/25. Had this parameter been changed, patching would have been revealed as the superior treatment.”

Good work, mixed messages

In the past year, media response to the initial reported outcomes of the study overshadowed physicians’ doubts concerning the equality of penalization compared to occlusion.

There was “an unprecedented amount of misleading lay media coverage suggesting that atropine was superior to, and should replace patching as a treatment for amblyopia,” Dr. Kushner wrote.

In addition, a second study released in Archives of Ophthalmology by PEDIG this year (“A randomized trial of patching regimens for treatment of moderate amblyopia in children”) said that 2 hours of patching with 1 hour of near work may be as effective as 6 hours.

“These messages are confusing to pediatric ophthalmologists,” Dr. Gold said. “First we are told that atropine and patching are equally effective, then we are told that 2 hours of patching is equivalent to 6. But now it comes out that atropine is indeed less desirable from a clinical standpoint, and the greatest number of hours for patching is most effective in treatment.”

While both Drs. Gold and Kushner commend PEDIG for its “good science” in reviving a nearly lost amblyopia treatment, they believe there is confusion in the pediatric ophthalmological community.

Customizing treatment is key

“We are getting many messages, but the key to the whole thing is to individualize your treatment,” Dr. Gold said. “We’ve got a lot of choices here, and what the PEDIG gave us was food for thought. It’s given us the opportunity to be a little more flexible with our treatments.”

Dr. Kushner wrote: “In my mind, these studies show us that atropine does work, perhaps better than any of us had anticipated … atropine is a reasonable alternative to patching for the noncompliant child.”

“It’s another tool you can use to treat moderate amblyopia,” said Dr. Gold, who said he has been using atropine more in the last year than he ever has in his 20 years of practice. “It’s an alternative for noncompliant children and parents. Sometimes it’s used as a last resort when the patient and family are not following through with occlusion therapy.”

Further study needed

Despite all the data, there is still no clear consensus on the ideal treatment for amblyopia.

“Patching definitely works much more quickly, results in a better final visual outcome and is a more known quantity with respect to adverse effects on binocular vision and fusion,” Dr. Kushner said.

Dr. Gold said that atropine expands the pediatric ophthalmologist’s armamentarium. “Knowing your patient and their family is key to customizing your treatment for every patient. What works for some children doesn’t work for others,” he said.

Both doctors agree that future study by PEDIG calls for a further evaluation of atropine in acute amblyopia — above levels of 20/100 — and in the preverbal or noncompliant child, where atropine has been most useful.

Additionally, Dr. Kushner said, studies assessing the outcomes of binocular vision and fusion in a child treated with atropine are needed to fully understand the treatment’s short- and long-term safety on vision.

For Your Information:

• Burton J. Kushner, MD, can be reached at the Department of Ophthalmology and Visual Sciences, University of Wisconsin, 2870 University Ave., Suite 206, Madison WI 53705; (608) 263-6414, (800) 323-8942; fax: (608) 263-4247.
• Robert S. Gold, MD, can be reached at 225 W. State Road 434, Suite 111, Longwood, FL 32750; (407) 767-6411; fax: (407) 767-8160; e-mail: rsgeye@aol.com.

References:

• The Pediatric Eye Disease Investigator Group. A comparison of atropine and patching treatments for moderate amblyopia by patient age, cause of amblyopia, depth of amblyopia, and other factors. Ophthalmology. 2003;110:1632-1638.
• Kushner BJ. Discussion. Ophthalmology. 2003;110:1637-1638.