AMBLYOPIA:
The condition is also known as lazy eye. It is an eye disorder affecting children where nerve pathways between the eye and brain don’t stimulate together, which results in improperly developed vision in one of the eyes. Rarely does it affect both the eyes.
Etiological factors:
Refractive errors: myopia, hypermetropia, and astigmatism early in childhood can lead to amblyopia.
Ptosis: also known as drooping eyelids, can affect vision and lead to amblyopia.
Strabismus: a condition where both eyes point in different directions, affecting the child's vision and contributing to amblyopia
Cloudy eyes: sometimes children born with cataracts have hazy lenses and blurred vision, which can lead to amblyopia.
Treatment:
The various treatment options should involve making the child use the weaker eye, as strengthening the weaker eye is the only option for amblyopia. This can be done by:
Wearing eyeglasses with blurred lenses in stronger eyes
Putting eye drops in stronger eyes to blur the vision
Wearing an eye patch over the stronger eye
Sometimes, surgery is also recommended to treat the cause of amblyopia.
A virtual reality (VR) headset can make children watch videos using weaker eyes.
A study titled “High-adherence dichoptic treatment versus patching in anisometropic and small angle strabismus amblyopia: a randomized controlled trial," published in the American Journal of Opthalmology was carried out to compare the effectiveness and safety of a novel binocular eye-tracking-based home treatment (CureSight) to patching for the treatment of amblyopia.
For the study, about 149 children aged between 4 and 9 years suffering from either anisometropic, small-angle strabismic, or mixed-mechanism amblyopia were enrolled, and the study was carried out for 16 weeks.
CureSight is an eye tracking-based system approved by the FDA in 2022, designed to improve visual and stereo acuity by training the visual system to use both eyes simultaneously. The CureSight system blurs the image corresponding to the center of vision of the dominant eye according to the severity of amblyopia while keeping the rest of the image sharp. The blurring is done in real-time according to the momentary gaze position of the dominant eye while the amblyopic eye receives a normal, sharp video stream. The visual system in the CureSight takes details from the amblyopic eye and simultaneously integrates them with information from the stronger eye. This way, visual acuity is improved in the amblyopic eye, and when two eyes are working together, stereo acuity is simultaneously increased.
The YouTube video posted by NovaSight demonstrates how the CureSight technology works.
Randomly, the participants were divided into two groups. One group used the CureSight system for 90 minutes a day, 5 days a week for 16 weeks (120 hours), and can be named a binocular treatment group. The other group received 2-hour patching for 7 days a week (224 hours) for 16 weeks and can be titled as the patching group.
For the results, two analyses were carried out: modified intent-to-treat (mITT) dataset analysis and per protocol (PP) dataset analysis.
In the modified intent-to-treat (mITT) dataset analysis, an improvement from baseline to week 16th in the binocular treatment group was non-inferior to the patching group. Whereas in the per-protocol (PP) dataset analysis, the mean improvement from baseline to week 16th in the binocular treatment group was superior compared to the patching group. Concerning stereo acuity, by the 16th week, both groups showed median improvement. However, when compared, both groups showed no significant difference, which means that both treatment options are equally effective for improving stereo acuity. And VA improved in both groups, reflecting the effectiveness of both treatments in amblyopia. Regarding adherence, the binocular treatment group showed a median adherence rate of 94%, whereas the patching group showed 83.9% adherence, which shows that the binocular treatment group is more preferred among children.
In a video shared on the Facebook page of EagleEye Performance Vision, Dr. Neil Renaud, behavioral optometrist and owner of EagleEye Performance Vision, shared his thoughts on treating amblyopia. In the video, he discussed various treatment options, in which first he mentioned about a 500-year-old traditional treatment option patching. He discussed how it works and can be used to improve visual acuity. He said it is important that we advance from the patching, as the problems associated with patching are that its treatment targets only affected eye. It mostly involves training the patient to use only one eye.
In the patching, nowhere does the treatment involve training depth perception. It's not training to use both eyes together. There is no ability to use eyes together as a team. Vision therapy helps in every area of life—binocular vision therapy—where kids are trained to use both eyes together. We can train on how to develop depth perception ability in the brain. We can improve acuity, break suppression, and learn how to see in 3D depth perception. We can also learn how to use both eyes together as a team so that we can see a single and clear picture with both eyes. Not that patching is bad, but just that vision therapy can do so much more.Dr. Neil Renaud, Behavioral Optometrist and Owner of EagleEye Performance Vision
He mentioned that vision therapy can be viewed as a long-term option. He also mentioned that irrespective of age, amblyopia can be treated, whether it is a 10 or 15-year-old child or a 35 or 50-year-old man; there is no critical period for treatment. He also stressed the fact that some level of amblyopia stays for the rest of his life, as it’s a condition hard to get rid of completely. The goal is to get better than where you are and get better vision.
The study findings suggest that the binocular eye tracking-based amblyopia treatment is as effective as patching and is more acceptable to children.
REFERENCES:
1. Nova-Sight. (2024b, June 10). CureSight amblyopia treatment. https://nova-sight.com/curesight-amblyopia-treatment/
2. Amblyopia: What is Lazy Eye? (2023, November 13). American Academy of Ophthalmology. https://www.aao.org/eye-health/diseases/amblyopia-lazy-eye
3. Wygnanski-Jaffe, T., Kushner, B. J., Moshkovitz, A., Belkin, M., & Yehezkel, O. (2024). High-adherence dichoptic treatment versus patching in anisometropic and small angle strabismus amblyopia: a randomized controlled trial. In American Journal of Ophthalmology. Elsevier BV. https://doi.org/10.1016/j.ajo.2024.08.011
4. Sylvia, J., Kohli, K. K., Sylvia, J., Kohli, K. K., & Dialogues, M. (2024, September 5). Medical dialogues. Medical Dialogues. https://medicaldialogues.in/amp/ophthalmology/news/new-eye-tracking-based-treatment-as-effective-as-patching-for-amblyopia-in-children-claims-study-134331