Combined Atropine & Patching bests patching alone for improving amblyopic eye Visual Acuity: JAMA
Amblyopia is one of the most common causes of monocular vision impairment in children, young adults, and middle-aged adults. Severe amblyopia refers to the best-corrected visual acuity (VA) of the amblyopic eye of 20/ 100 or worse. Although patching therapy is the first choice for treating severe amblyopia, it is often found to be less effective as a result of poor adherence, as patients may remove the eye patch earlier than recommended owing to the poor residual acuity when the fellow eye is occluded especially in children adherence may be even worse.
Adherence to atropine treatment, an alternative treatment for amblyopia, has been shown to be better than adherence to patching, but the use of atropine without patching was considered to be insufficient for severe amblyopia. When combined atropine and patching therapy (CAPT) was applied to treat severe amblyopia, it could potentially solve the problem of treatment failure due to poor patching adherence, without the concern of insufficient blurring effect in the fellow eye by atropine.
To study the treatment of severe amblyopia, Shu Wang and team conducted a randomized clinical trial to compare the efficacy of CAPT vs patching alone therapy in children aged 3 to 12 years with severe amblyopia as published in JAMA Ophthalmology.
This single-center randomized clinical trial was conducted from November 2018 to May 2020. The visual acuity (VA) examiner was masked to the treatment groups. The follow-up visits were at 3 months and 6 months. Participants aged 3 to 12 years with severe amblyopia (20/100 to 20/500) resulting from strabismus, anisometropia, or both were randomly assigned to CAPT or patching therapy.
Children in the patching group received patching of the fellow eye for 6 hours per day and the patching time should have been continuous. Participants were instructed to do near visual activities such as painting or playing video games for at least 1 hour when wearing the patch. Children allergic to the eye pads were prescribed a cloth patch mounted on the eyeglass frame.
Children in the CAPT group were prescribed patching of the fellow eye as mentioned above and 1 drop of atropine sulfate, 1%, eye gel once a day for the first 3 days and then once every 2 days. Parents were reminded that children should wear sunglasses or a hat when outdoors to avoid sunlight exposure.
If the amblyopic eye VA improved to be 1 line lower than the fellow eye VA at 3 months, the patching time would be decreased to 2 hours per day, and the use of atropine would be reduced to twice a week.
The primary outcome was the change of amblyopic eye VA from baseline to 6 months. The secondary outcomes were: (1) the change of amblyopic eye VA from baseline to 3 months, (2) the proportion of participants with amblyopic eye VA of 20/32 or better at 6 months, and (3) the proportion of participants with an fellow eye VA decrease of 1 line or more at 6 months.
- Among 108 participants, the mean (SD) age was 5.2 (1.8) years, and 54 (50%) were female.
- Overall, 53 participants (49%) were randomized to CAPT and 55 (51%) were randomized to patching therapy.
- At baseline, the mean (SD) amblyopic eye VA was 0.95 (0.22) logMAR (approximately 20/200 [2.2 lines]).
- At 6 months, the CAPT group's mean improvement in amblyopic eye VA was 0.72 logMAR (7.2 lines) compared with 0.58 logMAR (5.8 lines) in the patching alone group (difference, 0.14 logMAR [1.4 lines] greater in the CAPT group; 95% CI, 0.05-0.22 logMAR [0.5-2.2 lines]; P = .002).
- The amblyopic eye VA improvement in the CAPT group also was greater than that in the patching alone group at 3 months (difference in the means, 0.13 logMAR [1.3 lines]; 95% CI, 0.04-0.22 logMAR [0.4-2.2 lines]; P = .004).
- No participants were withdrawn because of adverse effects.
- While the CAPT group mean amblyopic eye VA improvement was superior to the patching group at 3 months and 6 months, the differences were relatively small.
The subgroup analysis showed no significant interaction between interventions and baseline VA subgroups (VA, ≤20/200 or >20/ 200), which suggested that CAPT achieved more improvement in amblyopic eye VA than patching in the initial 6-month treatment, even when baseline VA was as poor as 20/200 or lower. Authors speculated that atropine, as a cycloplegic that can prevent accommodation, could induce blurred vision in the fellow eye at near fixation to force participants to use the amblyopic eye more when the fellow eye was not covered.
In this study, participant adherence with patching time was similar in both groups. It indicated that the difference in VA change between the 2 groups was attributed to the effect of atropine treatment.
Participant adherence to the use of atropine was excellent in 75% of participants in the CAPT group. Moreover, there were 7 participants in the patching group with an improvement in amblyopic eye VA of 3 lines or less and none in the CAPT group at 6months. These findings suggest that the CAPT would be more helpful for children who have poor adherence with patching.
The current study indicated that both the CAPT and patching alone therapy were efficacious for children aged 3 to 12 years with severe amblyopia. CAPT resulted in more mean improvement of amblyopic eye VA than patching alone, although the differences were relatively small and the clinical relevance of this difference cannot be determined by this trial.
Source: Shu Wang, Wen Wen, Wenqing Zhu et al; JAMA Ophthalmol.
doi:10.1001/jamaophthalmol.2021.2413
