Amblyopia is one of the common reasons for the visual problem in children. It is also known as ‘lazy’ eye and occurs when the nerve pathways between the brain and the eye don’t function properly. Individuals with amblyopia may have blurry vision even with glasses. This abnormal development of vision occurs in infancy or childhood. There are several types of amblyopia with different causes, but all exhibit poor vision of the affected eye.
Causes Some of the various causes associated with the different types of amblyopia include strabismic, deprivation and refractive.
- Strabismic amblyopia
This is one of the common causes of amblyopia. This occurs with the misalignment when the eye is not straight and may turn in, out, up or down resulting in double vision. This happens when the brain ‘turns off’ the visual input of the affected eye creating amblyopia.
- Deprivation amblyopia
This occurs when the certain condition causes problems affecting the line of vision. It can include the presence of cataract, droopy eyelid and an eyelid lesion. Early treatment is required to enable the development of normal vision.
- Refractive amblyopia
This develops with an unequal refractive error between the two eyes and can consist of farsightedness or nearsightedness. The brain may ‘turn off’ the eye producing blurred vision causing amblyopia from the disuse of the eye.
Symptoms: As amblyopia affects the infant’s vision, the symptoms can be difficult to identify. Generally, strabismus is the common cause of amblyopia. Hence, children identified with eye misalignment should have an eye examination. An indication of amblyopia includes children who may become irritable when one eye is covered during a visual task such as reading.
Diagnosis: It is usually not easy to detect the presence of amblyopia. Unless there is an obvious abnormality such as misaligned eye, it is often difficult for parents to understand the condition. However, during the eye examination, the eye specialist (ophthalmologist) may estimate the visual acuity by observing how the baby follows objects with single eye while the other one is covered. The tests may also include examining the inside of the eye to detect if other disorders may be the cause of vision problems which could include tumors, inflammations and cataracts.
Treatment Early treatment is always advised. Children with refractive errors can be corrected with glasses or contact lenses. Those with the cataract require prompt treatment to minimize the risk of developing amblyopia. The other forms of treatment involve in enabling the children to use the weaker eye. This may involve the patching or eye drops to blur the better vision eye. The patching may be effective when started early allowing the weak eye to get stronger over time. This may require several hours a day for weeks or months. When the child is unable to wear the patch, the atropine drops will be used to temporarily blur the vision of the strong eye. However, the pediatric ophthalmologist can select the appropriate treatment regime. Children affected with strabismic amblyopia can have a surgery to straighten the misaligned eye, followed by eye patching and vision therapy to assist the normal function of both eyes.
References http://www.allaboutvision.com/conditions/amblyopia.htm http://www.strabismus.org/amblyopia_lazy_eye.html http://www.aao.org/eye-health/diseases/amblyopia-lazy-eye-diagnosis http://www.visionaware.org/info/your-eye-condition/guide-to-eye-conditions/amblyopia-6143/125