A retrospective comparative analysis of the efficacy of Fresnel prisms, botulinum toxin injection and strabismus correction surgery in the treatment of acute acquired comitant esotropia
This retrospective comparative study of 101 children with acute acquired comitant esotropia demonstrates that while all three treatments (Fresnel prisms, botulinum toxin injections, and surgery) are safe, strabismus correction surgery offers the most rapid and stable long-term functional recovery, whereas botulinum toxin and Fresnel prisms serve as viable alternatives for specific patient profiles based on strabismus severity and individual needs.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine your eyes are two tiny, hardworking cameras that usually work together to take perfect, 3D pictures of the world. But sometimes, especially in kids and teens, these cameras suddenly decide to look inward at the same time, crossing their lenses. This is called Acute Acquired Comitant Esotropia (AACE). It's like a glitch where the cameras stop syncing, causing double vision and making it hard to focus on schoolwork or play.
A team of researchers at the Children's Hospital of Hebei Province decided to run a "race" to see which of three different repair kits works best to fix this glitch. They looked back at the records of 101 children (aged 2 to 14) who had this problem between 2020 and 2023. They split the kids into three teams, each trying a different method:
- The "Sticky Lens" Team (Fresnel Prisms): These are special plastic stickers you put on glasses. They bend the light so the eyes look straight without actually moving the muscles. It's like putting a filter on a camera to trick it into seeing straight.
- The "Muscle Sleep" Team (Botulinum Toxin Injection): This involves a tiny shot of medicine (Botox) right into the eye muscle. It temporarily puts the muscle to sleep so it can't pull the eye inward too hard. Think of it as hitting the "pause" button on a muscle that's pulling too tight.
- The "Surgery Team" (Strabismus Correction): This is the big fix. Doctors gently loosen the tight muscles and tighten the loose ones under general anesthesia. It's like a mechanic physically adjusting the cables on the camera to make them pull in the right balance forever.
The Race Results
The researchers checked the kids' eyes at 1 month, 3 months, and 6 months to see who won. Here is what they found:
The Winner: The Surgery Team
The surgery group was the clear champion for getting the eyes straight and keeping them that way.
- One month after treatment: The surgery group had the straightest eyes, with a leftover "crossing" angle of just 2.01±1.59 PD (prism diopters). This was significantly better than the Botox group (2.56±1.71 PD) and way better than the Prism group (4.18±1.82 PD).
- Three months later: The surgery group was the only one where 100% of the kids got their "fusion" (the ability to blend two images into one) back, and 100% got their sharp, central 3D vision (stereopsis) back. No one in this group had their eyes cross again.
The Runner-Up: The Botox Team
The injection team did a great job in the short term, but they had some hiccups.
- Their eyes were quite straight at one month (2.56±1.71 PD), almost as good as surgery.
- By three months, 86.5% of them had good fusion, and 94.6% had good 3D vision.
- The Catch: Because the medicine wears off, there is a risk the eyes could cross again. Also, the "sleep" shot sometimes accidentally made the eyelid droop (ptosis) in 13.5% of kids or caused the eyes to look up/down (vertical strabismus) in 10.8% of kids.
The "Wait-and-See" Team: The Prism Group
The plastic stickers were safe and easy, but they weren't the strongest fix.
- At one month, their eyes were still the most crossed, with a leftover angle of 4.18±1.82 PD.
- By three months, only 59.4% had good fusion and 62.5% had good 3D vision.
- The Catch: A quarter of the kids (25.0%) felt uncomfortable because the stickers made the world look a bit blurry or wobbly. The researchers noted these are best for mild cases or as a temporary fix while waiting for something else.
The Verdict
The study suggests that if a child has a moderate to high degree of eye crossing (between 20 and 40 PD) and really wants their 3D vision back, surgery is the most reliable way to get it done quickly and keep it stable.
If surgery isn't an option (maybe the family is worried about anesthesia or the crossing isn't too bad), Botox injections are a good, less invasive backup, but the family needs to know the eyes might cross again later.
Fresnel prisms are a safe, non-invasive tool, but the paper suggests they are mostly useful for very mild cases or as a temporary bridge to help a child see clearly while waiting for the right time for surgery. They aren't a magic cure-all for everyone.
What the Study Rules Out
The researchers were very careful to check the kids first. They ruled out that this problem was caused by brain tumors, nerve damage, or other serious diseases in these children (unlike in some adults). They also confirmed that the kids didn't have a history of eye injuries or previous eye surgeries.
How Sure Are They?
The authors are confident in these numbers because they measured them directly over a 6-month period for 101 real patients. However, they admit their study has limits: it was a "look back" at records (not a new experiment they controlled from day one), the group size was relatively small, and they only followed the kids for 6 months. They suggest that future studies need to watch even more kids for over a year to be absolutely sure about long-term results. But for now, the data points clearly to surgery being the most stable fix for this specific eye problem.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.