What is Anisometropia
Anisometropia is known as a condition where both human eyes have different refractive powers that cause eyes to focus unevenly. The typical anisometropia usually occurs when one is different in size or shape from the other, leading to asymmetric near-sightedness, asymmetrical curvatures, or asymmetric farsightedness. One of the most common causes of amblyopia is anisometropia, more commonly known as "lazy eye". There are very few people who are born with two eyes of identical optical power, yet, the brain manages to compensate and makes it unnoticeable. There are three types of anisometropia:
- Simple anisometropia- Only one eye is effected while the other does not have a refractive error.
- Mixed anisometropia- Both eyes have appreciable refractive errors with one being myopic and the other being hyperopic.
- Compound anisometropia- Both eyes are short-sighted (Myopic) with a significant difference in their refractive errors.
The harm of Anisometropia
People who go through anisometropia are mostly asymptomatic, demonstrating no signs of issues with the vision. Others may feel mild problems with the vision, but none of the problems is noticeable unless properly examined. Anisometropia can affect a person's binocular vision. Anyone with anisometropia usually a larger image from one eye and a small in the other. This causes blurry vision. As a consequence, one eye may become weaker than the other eye, allowing the brain to favor the stronger eye. Upon not identifying or treating on time, anisometropia can lead to amblyopia. Individuals with untreated anisometropia may experience the following symptoms:
- Visual Discomfort
- Poor depth perception
Even though anisometropia can be present at the time of birth, it is usually not diagnosed till childhood. Various assessments have suggested that nearly 6 percent of all children from 6 to 18 years experience anisometropia.
How to promote and treat anisometropia
If there is a significant alteration in the refractive power of both the eyes, one retina receives a clear picture than the other. This causes amblyopia to develop in the eye with low image quality. As there is high brain plasticity in children, it is likely for the lesser quality image to suppress and children may usually overlook any abnormality. As per the American Academy of Ophthalmology, anisometropia will possibly be triggered if refractive alterations between the two eyes are higher than 1.50 D of hyperopia, 2.00 D of astigmatisms (cylinder diopter), and 3.00 D of myopia (minus diopter). After it is diagnosed, the approach for treatment for anisometropic amblyopia will be similar to any other amblyopic etiology. The focus will be more on refractive correction which will prevent amblyogenic anisometropia. A few children will react to refractive correction actions, while others will enjoy the addition of penalization, patching, or vision training. Generally, the prognosis is very effective if the condition is identified and addresses in the early stages. Thorough and frequent screenings are hence, important to let refractive differences unrecognized.
There are several ways to treat Anisometropia. The most common way is to use corrective lenses, however, they only work for individuals with a difference of lens and not 4D between their eyes.
For children less than 12, it is recommended that sight must be corrected with the help of contact lenses. This makes sure that both the eyes have the best possible vision, as contact lenses can facilitate development. Adults or older children can use glasses or contact lenses to fit their visions. People with severe anisometropia are opined to use contact lenses. The corrective method is a suitable method for patients with anisometropia. This method can permanently help solve all the problems. There are several typical surgical therapies which include:
- Removing the crystalline lens- The crystalline lens is the natural lens of the eye. For a few people, the overall vision can be improved by just removing the lens. The eyesight can be adjusted with additional surgeries or special glasses.
- Refractive corneal surgery – This is used to enhance the cornea's refraction of light. With the help of this surgery, astigmatism, unilateral myopia, and hypermetropia can be corrected.
- Intraocular lens implantation-IOL, most commonly known as the intraocular lens implantation in common surgery for the ones that have astigmatism or cataract in their eyes, severely impacting their quality of life. Even though there are several variations in this surgery, generally, the eye is precisely cut so that the doctor can break up the natural lens. A plastic lens is then put in place to fix the vision.
- Phakic IOL- This is intraocular lens implantation which is similar to intraocular lens implantation IOL. However, it does not remove the crystalline lens. The intraocular lens is placed along with the natural lens in the eye. The two lenses work together to fix the vision.
No surgery comes without risks. Even though the surgeries mentioned above are not dangerous, there is still a possibility of complications leading to a lack of visual clarity, blindness, or infection. You may most likely experience swelling or redness.
If you have any concerns, simply talk to your doctor. Immediately report any problem if you experience any.
Strictly follow the recovery plan your doctor gives you. Your recovery time may be vulnerable, and there are chances you may damage the eye. It is better to ask your doctor what you must avoid, what you must expect, and how long will it take for you to recover.
Do not touch your eye as it heals, although it may release fluid or itch. Your doctor will likely give you medicated eye drops that help you to recover.
Does anisometropia need to wear eyeglasses?
Typically, glasses are less suitable for individuals with huge degrees of anisometropia. As they can come with a magnification effect, a considerable effect can be created by glasses in the image size, especially, when it is seen by each eye, preventing an affective binocular vision. Contact lenses are good for people with a 4D difference in their eyes below. It is strictly advisable for young children who are under 12 with severe anisometropia to use contacts, whereas others can wear glasses for correction.