Some abnormalities cannot be seen with the naked eye, such as “lazy eye”, or what grandparents call “blind-clear eye disease”, because the external appearance usually shows no abnormalities. However, patients will have blurred vision and unclear sight; some may have strabismus. Dr. Natsucha Wangthiranaw, a pediatric ophthalmology specialist at Phyathai 3 Hospital, said that when parents do not know their child has lazy eye, they do not take the child to see a doctor for treatment at the appropriate time.
What is “lazy eye”?
Dr. Natsucha explained that lazy eye occurs when both eyes do not see clearly equally. The body chooses to use the eye that sees more clearly, causing the development of the visual nerve to be stimulated in only one eye, resulting in clear vision in one eye only. Or it may be caused by both eyes seeing unclearly, causing the brain to develop other sensory nerves instead, resulting in blurred vision in both eyes.
In normal people, the development of the visual nerve occurs rapidly from birth to 3 months of age and continues to develop until 9 years old. Therefore, if not treated during this period, it is usually no longer treatable.
These causes lead to lazy eye
- There is an obstruction preventing the eye from seeing images (Deprivative amblyopia) – such as drooping eyelids, cloudy cornea, cataracts, or bleeding in the eye. These conditions cause the visual part of the brain not to develop according to age.
- Strabismus (Strabismic amblyopia) – causes the brain to choose to receive images from only one eye to avoid double vision. If the brain repeatedly chooses images from only one eye, the other eye may become lazy.
- Different degrees of nearsightedness, farsightedness, or astigmatism in the two eyes (Anisometropic amblyopia) – when one eye has a high degree of nearsightedness, farsightedness, or astigmatism and is not corrected with glasses, the other normal eye can see clearly. The brain then chooses to see with the clearer eye only, causing the other eye not to develop and become lazy.
- High degrees of nearsightedness, farsightedness, or astigmatism in both eyes (Isoametropic amblyopia) – without correction with glasses, neither eye sees clearly. The visual part of the brain receives little stimulation. This case may cause lazy eye in both eyes.
How to know if your child has lazy eye
Dr. Natsucha said that parents should carefully observe their children for any abnormalities, such as drooping eyelids, white spots on the cornea or in the eye, strabismus, squinting, tilting the head or face, or preferring to look closely. If these symptoms are found, they should take the child to see a doctor early. If there are no external abnormalities, try testing by covering one eye at a time and using toys to attract attention. If one eye does not react to the toy, it indicates that the eye may not see clearly and may have lazy eye.
How to treat to return to normal
Treating lazy eye patients at a young age increases the chance of returning to normal vision because there is still a period during which visual development can proceed normally. Dr. Natsucha said that after bringing the child to see a doctor, the doctor will choose the appropriate treatment method for each patient, such as correcting the cause, surgery for drooping eyelids, cataract surgery, prescribing glasses to correct vision, strabismus surgery, eye drops in the clearer eye to blur vision, or patching the clearer eye to stimulate development of the weaker (lazy) eye.
If detected after the age of 9, it is not completely hopeless. Treatment may still be somewhat beneficial, as there are reports of patients aged 11-17 years showing improvement.
Parental cooperation is crucial
Dr. Natsucha explained that the most important thing is that treating lazy eye in children requires strong cooperation from the parents because it is not easy to have the child cover the clearer eye to use the weaker eye. Most children will fuss and cry. Parents may need to spend time playing or doing activities with the child while the eye is covered. If the child is left alone with the eye covered, they often remove the patch, peek, or fall asleep, which is equivalent to not receiving treatment.
If parents can strictly follow the doctor’s advice, the treatment results are usually good, and the child’s vision can function normally throughout life.
