Astigmatism is a simple refractive error or an eye condition casing blurry or distorted vision.
In Astigmatism refraction of light is not normal as light usually passes to retina. Brain translate the impulses from optic nerves into the eyesight.
Cornea and lens behind it refract light on the retina. Sometimes images do not focus on retina properly, If there are any abnormalities in the curvature of cornea or lens resulting in distorted or unclear images as perceived by brain .
Apart from Myopia i.e. nearsightedness and Hyperopia i.e. farsightedness, Astigmatism is also a common kind of refractive error.
A dome like structure covering front surface of the eye, cornea is transparent if perfectly curved focuses light signals on retina to form an image. In Astigmatism, corneas and lenses have imperfect curves which generates distorted vision due to error in refraction. Astigmatism also occurs due other structural defects within the eye.
Symptoms of astigmatism
Common signs and symptoms of astigmatism include:
- Squinting
- Blurred or distorted vision at all distances
- Poor night vision
- Double vision in one or both eyes
- Eyestrain
- Headaches
Diagnosis
While testing, eyeball is scanned to measure its surface in three dimensions,these sections of the eyes known as meridians help doctor to identify spots on cornea that generates astigmatism. Diopter estimates the amount of refraction happening in each meridian.
Eye doctor usually does retinoscopy to check the eyesight. Meridians of the eye are similar to a clock, where a vertical line between 12 to 6 and horizontal line between 9 to 3 are two different meridians, he verifies the difference between the meridians so an appropriate prescription can be given for clear vision.
Astigmatism in children
Newborns frequently exhibit astigmatism, but this condition typically resolves itself within the first year of life. By the age of 5 to 9, only a small number of children display signs of astigmatism. However, some kids might not outgrow their astigmatism, and if left uncorrected, it can hinder their learning and development. Therefore, it’s crucial to arrange regular eye examinations for children to identify astigmatism and any other uncorrected refractive issues.
Read more: Astigmatism in children
Types of astigmatism
Astigmatism has three primary classifications, defined by the principal meridians (the steepest and flattest meridians of the eye).
- Myopic astigmatism: Principal meridians of the eye are nearsighted (myopia + astigmatism).
- Hyperopic astigmatism: Principal meridians are farsighted (hyperopia + astigmatism).
- Mixed astigmatism: Principal meridians are both near and farsighted (astigmatism is the primary refractive error).
You may also see astigmatism described as:
- Corneal: Defects in the cornea.
- Lenticular: Defects in the lens of the eye.
- Regular: Principal meridians are perpendicular (90 degrees apart).
- Irregular: Principal meridians are not perpendicular (sometimes caused by injuries and scarring of the cornea). Keratoconus, a long-term thinning of the cornea, and some forms of eye surgery also can cause irregular astigmatism.
Treatments for Astigmatism
Eyeglasses, contact lenses, and certain eye procedures like LASIK can address astigmatism. **Eyeglasses** Prescription lenses are designed to fix refractive issues in the cornea and lens of the eye. According to the American Academy of Ophthalmology, a typical astigmatism can usually be corrected to a vision of 20/20, although in some cases, the severity of the astigmatism may prevent normal vision correction. An irregular astigmatism often cannot be improved to 20/20. **Contact Lenses** Many individuals opt to manage their astigmatism with contact lenses, which are available in three main types:
- Toric These soft contact lenses can possess varying degrees of refraction that correspond to the specific meridians of the eye, facilitating accurate vision corrections. Due to their intricate designs, toric contact lenses intended for astigmatism are frequently more costly than other varieties.
- Gas Permeable. These rigid lenses possess a consistent shape that effectively substitutes the cornea’s refraction effect. They frequently offer clearer vision compared to their softer toric equivalents. It is important to note that certain gas-permeable lenses utilize toric designs. Initially, gas-permeable lenses may be less comfortable than toric lenses; however, they deliver excellent vision correction and comfort over time.
- Hybrid. These lenses feature a rigid center to enhance visual clarity while maintaining a softer edge for increased comfort. They frequently offer an optimal combination for correcting astigmatism with contact lenses. It is important to consider that hybrid and gas permeable lenses necessitate additional time and expertise for an accurate fitting, so keep this in mind when making your purchasing decisions.
Astigmatism Surgery
Procedures aimed at reshaping the cornea and eliminating cataracts can effectively address astigmatism. For example, LASIK surgery employs high-precision lasers to enhance the symmetry of the cornea, thereby providing a permanent solution for moderate levels of astigmatism. Additionally, an ophthalmic surgeon has the option to insert a toric intraocular lens (IOL) to rectify astigmatism while simultaneously removing a cataract. It is important to note that if your health insurance does not cover the procedure, a toric IOL may incur significantly higher costs. Since surgery is a permanent solution, it is essential to consider the associated risks and ensure that your physician confirms your suitability for the procedure. Each individual’s vision is distinct, indicating that every type of astigmatism can have a different effect. Consequently, it is crucial to pay close attention to the fit and performance of your eyeglasses or contact lenses. Furthermore, refrain from proceeding with surgery until you have thoroughly researched the subject and consulted with your eye care professional.
FAQs
Q: How does astigmatism affect night driving?
A: Driving at night with uncorrected astigmatism can prove to be a challenging endeavor. This difficulty arises because astigmatism leads to the scattering of light within the eye instead of concentrating it on a singular point (the retina). Individuals with astigmatism may experience distracting glare, halos, or streaks from street and traffic lights. Such visual disturbances can adversely impact night driving.
Q: Can you get contact lenses for astigmatism?
A: Indeed, it is possible to obtain contact lenses designed for astigmatism. There are three primary types available: soft toric lenses, gas permeable lenses, and hybrid lenses. Each type of lens provides distinct advantages, therefore it is advisable to consult with your eye care professional to determine which contact lenses for astigmatism are most suitable for your needs.
Q: How are astigmatism glasses different from other glasses?
A: Astigmatism glasses differ from standard glasses due to an additional specification regarding lens power. The cylinder measurement (abbreviated as CYL on a vision prescription) indicates if a lens requires extra power to correct astigmatism. Individuals with astigmatism will also have an AXIS specification, which indicates the orientation of the astigmatism correction. Conversely, individuals without astigmatism will not possess a CYL or AXIS specification.
Your eye doctor will evaluate all possible treatment options with the aim of achieving clear, comfortable, and effective vision. For more details logon to our website www.lasikvision.in
