Can LASIK Cure Cylindrical Power? What Indian Ophthalmologists Say
What is Cylindrical Power?
Cylindrical power in the eyeglass prescription is generally referred to as astigmatism, where light focused on the retina is improper. Cylindrical power indicates the degree of astigmatism and represents the additional lens power required to correct an astigmatic refractive error.
Astigmatism is a condition where multiple focal points are created due to irregularity in the shape of the lens or the corneal layer of the eye. It leads to blurred vision at all distances, formation of stretched or distorted images, excessive strain in the eyes and head, difficulty seeing objects at night, and the need to squint the eyes to focus on objects.
Irregularity in the shape of the cornea, irregularity in the shape of the lens, several genetic factors, trauma, injuries to the eye, and certain eye conditions are some of the causes of astigmatism.
There are two types of astigmatism:
- Regular astigmatism refers to the condition where the cornea curves more in one direction than the other.
- Irregular astigmatism refers to curvature that varies across multiple meridians.
Ways to Manage Cylindrical Power
There are several ways to manage cylindrical power, ranging from traditional corrective lenses to advanced surgical procedures. Here is a list of different approaches to manage astigmatism:
- Corrective eyewear or eyeglasses is the most common method to manage astigmatism. Cylindrical lenses are usually used for irregularities in the cornea or eye lens. High-index materials are used for stronger prescriptions. To reduce glare and halos, anti-reflective coating glasses are also available.
- Contact lenses, along with eyeglasses, are also available to maintain proper orientation of the eyes. The most commonly used contact lenses are toric soft contacts.
- Surgical interventions involve the use of LASIK (Laser-Assisted In Situ Keratomileusis). This procedure involves the creation of a corneal flap before reshaping the cornea to improve vision and provide a long-term solution for refractive errors due to astigmatism.
- Surgeries such as astigmatic keratotomy or limbal relaxing incisions are also performed for higher levels of astigmatism.
How does LASIK Work to fix Cylindrical Power?
Before opting for any surgical procedure, ophthalmologists evaluate patients struggling with astigmatism through a thorough eye examination to assess various parameters, such as:
- Measurement of corneal thickness using methods like corneal topography and pachymetry.
- Examination of prescription strength through a refraction test.
- Checking for dry eyes using a tear film evaluation test.
- Examination of the retina and surrounding cells via pupil dilation.
If the health parameters of the eyes are optimal, the patient is advised on LASIK surgery. After finalising the LASIK procedure, rapid pulses of laser energy are used to create precise corneal flaps, which are about the thickness of human hair, using small circular equipment. To break the bonds between the cells of the eyes, an ultraviolet light beam is supplied for 20 to 90 seconds, depending on the correction needed. After that, the flap is carefully repositioned over the treated area. Post-LASIK care measures are used to allow the natural healing process and secure the flap in place without sutures.
Who Is Eligible to Correct Astigmatism via LASIK?
As discussed, LASIK is a minimally invasive and precise eye surgery designed for individuals seeking permanent vision correction. Below are the key factors that determine an ideal candidate for the LASIK procedure to correct Astigmatism:
- The individual must be 18 years or older with stable vision for at least one year before surgery.
- There are specific prescription ranges for different vision issues that must be met. For astigmatism, up to ±6D cylindrical power is permissible.
- Candidates should have good corneal health, meaning sufficient corneal thickness and no history of keratoconus or severe corneal scarring.
- The individual must not have any active eye infections or conditions such as glaucoma or cataracts.
- Candidates should not have autoimmune disorders such as lupus or rheumatoid arthritis.
- Individuals must be free from retinal diseases or uncontrolled diabetes-related eye conditions.
- Pregnant or breastfeeding individuals are not eligible, as hormonal changes can affect vision stability.
For more on LASIK and its treatments, check our LASIK treatment solutions.
After-care Measures post LASIK for Astigmatism
The aftercare within 24 to 48 hours of surgery is extremely crucial to ensure adequate healing and vision correction. Just after the surgery, you will experience sensitivity in your eyes. Below are the immediate post-operative care tips that you should follow:
- The LASIK surgery involves creating a thin corneal flap that takes time to reattach. During this time, it is crucial to avoid rubbing or touching the eyes, as it carries the risk of dislodging or wrinkling the flap. If the flap wrinkles, complications such as blurry vision may arise.
- Use prescribed eye drops at regular intervals as directed by the ophthalmologist to prevent bacterial infections, avoid dry eyes, and reduce swelling or redness due to surgery.
- Keep your eyes closed for the first few hours after the surgery, as it helps accelerate the healing process of the cornea. Eye movements may put unnecessary strain on the healing tissues, leading to discomfort. That is why you should avoid reading or using gadgets.
- After LASIK surgery, it is advisable to avoid any strenuous activity that can put pressure on and disturb the healing of the corneal tissue. Moreover, sudden jerky movements such as bending down or lifting heavy objects can lead to displacement of the flap created during surgery.
- After LASIK surgery, your eyes become sensitive to light. It is mandatory to protect them from UV rays and bright light, as exposure can damage the corneal lining and may even lead to regression. Additionally, protective eyewear prevents dust particles from entering the eyes.
Potential Risks of SMILE LASIK Surgery
Being an advanced and minimally invasive procedure, LASIK is considered an extremely safe vision correction surgery. However, it does carries some potential risks and side effects, which are outlined below:
- Some individuals may experience temporary blurry or hazy vision in the first few weeks after surgery. This typically resolves as the eyes heal and vision stabilizes. Temporary dryness is common post-surgery which can be effectively managed with lubricating eye drops prescribed by the doctor and used at regular intervals.
- Light sensitivity may occur after surgery. This is usually temporary and can be managed by wearing UV-protective sunglasses. Extremely rare complications include infection, inflammation, corneal irregularities, or epithelial ingrowth.
- Some individuals may also notice halos around lights, especially at night. In rare cases, the laser may not achieve the desired vision correction, leading to undercorrection (not enough vision improvement) or overcorrection (blurry vision).
An experienced best eye doctor in Mumbai can confirm LASIK suitability for cylindrical power.
Frequently Asked Questions (FAQs)
Is LASIK permanent for cylindrical power?
LASIK results for astigmatism are long-lasting, but that does not mean they are always permanent. Natural ageing of the eyes, along with changes in hormonal levels, can lead to regression or the development of new astigmatism over time.
Can LASIK remove cylindrical power completely?
Yes, with the LASIK procedure, complete elimination of cylindrical power is possible, especially in individuals struggling with mild to moderate astigmatism. However, it should be noted that complete correction is not guaranteed for everybody. While modern-day technologies have improved the LASIK technique significantly, absolute correction is not medically guaranteed.
Is LASIK better than glasses for astigmatism?
There are several advantages that LASIK offers over glasses for astigmatism. Glasses can cause peripheral visual distortion, discomfort due to fogging or glare, and dependence on corrective eyewear. On the other hand, LASIK provides ease from such issues and potentially delivers natural-quality vision.
What is the minimum cylindrical power for LASIK?
No minimum criteria for cylindrical power correction are required for LASIK. Mild astigmatism ranging from 0.5D to 0.75D can also be corrected via the LASIK procedure. The correction of cylindrical power via LASIK depends on a comprehensive evaluation of overall eye health and the visual needs of the patient.
Are results for astigmatism the same as for myopia in LASIK?
Both conditions, myopia and astigmatism, can be effectively corrected via LASIK procedures. However, it should be noted that astigmatism correction via LASIK is slightly less predictable than myopia due to age-related and hormonal changes.
