What is LASIK & REFRACTIVE SURGERY?
Laser-assisted in situ keratomileusis (LASIK) eye surgery is the best known and most commonly performed laser refractive surgery to correct vision problems.
Lasik & Refractive Surgery
- What are refractive errors:
- What is Contoura Vision?
- What is Trans PRK:
- What Is FemtoLASIK?
The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. The bending and focusing of light is also known as refraction. The imperfections in the focusing power of the eye due to the shape of the cornea and the eye results in blurred or distorted image formation on the retina. These are called refractive errors.
There are three primary types of refractive errors: myopia, hyperopia and astigmatism.
- People with myopia, or near-sightedness, have more difficulty seeing distant objects as clearly as near objects.
- People with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects.
- Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye.
Combinations of myopia and astigmatism or hyperopia and astigmatism are common.
How refractive errors are corrected?
Glasses or contact lenses are designed to compensate for the eye’s imperfections. Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery.
Refractive eye surgery is non-essential eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea, lens implantation or lens replacement.
Refractive surgery might be a good option for you if you:
- Want to decrease your dependency on glasses or contact lense
- Have an appropriate refractive error
- Are free of eye disease
- Understand that you could still need glasses or contacts after the procedure to achieve your best vision
Contoura Vision TopoGuided LASIK is a new technology designed to enhance the effects of LASIK (Standard LASIK/ Femto-LASIK). It corrects the vision based on the corneal topography (corneal curvature maps) and topolyser, as against the correction of vision in a standard LASIK surgery which is only based on glasses or contact lens prescription. It is a customized LASIK
What makes Contoura Vision so unique?
Corneal topography along with Topolyser has the capabilities to record the minutest irregularities in the corneal curvature. It provides the measurement of 22000 points as compared to the currently available wavefront-guided LASIK that measures approximately 200 points. These measurements are then combined with the patient’s glass prescription and customized treatment is planned and programmed into the laser.
Since Contoura Vision combines refractive prescription with corneal topography maps it provides improved quality of vision to the patients. Food and Drug Administration (FDA) results reveal that the patients who opted for this technology had a significant improvement and were able to see even more clearly without corrective eyewear. As per the clinical trials statistics, almost 90% of patients post-operatively saw as well or better without glasses than they ever did with glasses or contact lenses.
How does it help?
- Specifically suitable for patients with Astigmatism > 1D
- Decrease in difficulty during night driving
- Lesser sensitivity towards light, less glare
- Better quality of vision
How is it done?
Preparation:
A complete preoperative screening is done by clinical examination and corneal topography (Pentacam) to assess the eligibility and safety of the LASIK procedure for the patient. If any retinal lesions (like thinning/ hole/ tear) are found during the evaluation, they are treated first using barrage laser and LASIK is performed only after 1 to 4 weeks.
On the day of the procedure:
On the day of the procedure, the topographic images of the patient are captured using topolyser and the same is transferred to the treatment planning station to generate the customised treatment profile. Contoura Vision Femto-LASIK is done on WaveLight Refractive Suite, the fastest laser available in the world. A thin corneal flap is created first using the Bladeless Femtosecond technology on the FS 200 laser. Topoguided laser ablation for refractive correction is performed on the EX500 laser.
After the procedure:
The patient can leave the hospital 30 minutes after the procedure. Eye drops are prescribed to prevent infection and to facilitate the healing process. The patient is assessed the next day after the procedure and then 1 week and 1 month later.
TransPRK (Transepithelial Photorefractive Keratectomy) is a no-touch laser vision correction procedure in which a specialised (Excimer) laser is used for precise corneal skin layer removal and reshaping of the superficial layers of the cornea beneath. Corneal reshaping is computer controlled, and is based on the results of optical and corneal shape mapping tests carried out at your preoperative consultation. The rapid firing laser will emit 1050 pulses of laser energy per second, and at the same rate will track any eye movements that may occur during the procedure, resulting in a very quick and accurate treatment. A bandage contact lens is placed over the eye to assist epithelial regeneration/healing, which is usually removed 2-4 days following your treatment
Benefits of TransPRK:
Touchless: no suction, no flap, no incision. Truly all-laser procedure Safe, gentle and precise: Treatment takes place directly on the upper surface of the cornea. There are no cut or flap complications. This non-invasive method leaves a very stable cornea and thus provides high corneal stability and more safety for the patient
Fast: In just one step, the epithelium is removed and the refractive correction performed. This shortens the treatment time considerably; healing is faster than with manual method Versatile: TransPRK is suitable for all laser candidates wishing to see clearly. It is ideal for active and athletic people, and for professions where sharp vision is needed. TransPRK is also a good treatment option for patients with thin, pathological or irregular corneas.
Risks of Trans PRK:
Dry eye: Like Lasik flap procedures dry eye can occur with TransPRK laser surgery but is typically less severe and for a shorter duration. The condition is a result of nerve endings being lasered. With recovery and nerve regeneration, sensation returns and the dry eye improves.
Corneal haze: This is a fine haze sometimes seen on the cornea at about 6 weeks and typically recedes over the following 6 weeks. With modern low energy excimer lasers and low levels of laser correction, this is not seen as often. To avoid haze some surgeons use Mitomycin C.
Infection: In the early postoperative period, the eye is at a slightly higher risk of infection than Lasik laser eye surgery. This is because the top protective epithelium needs to regenerate. It is important that patients maintain good hygiene and follow instructions provided by your doctor.
FemtoLASIK (Femtosecond assisted laser in-situ keratomileusis) is a form of LASIK used to correct vision problems like nearsightedness (myopia), farsightedness (hyperopia) and astigmatism by way of deploying laser on the cornea.
What is FemtoLASIK?
The FemtoLASIK procedure is slightly different from Standard LASIK in the first step of LASIK surgery. The Standard LASIK involves a blade (microkeratome) to create a flap on the corneal surface and uses lasers to reshape the cornea. The use of mechanical blades may make irregular flaps or incomplete cuts which might potentially lead to post-surgery complications and irregular astigmatism. Whereas FemtoLASIK, also known as bladeless LASIK or all-laser LASIK does not use the blade, instead it substitutes blade for a femtosecond laser and uses an excimer laser to correct the refractive conditions thereby increasing efficiency, achieving optimum treatment results and the rapid recovery of vision.
Advantages over Standard LASIK
Enhanced safety:
By using Lasik, the risk of complications, which might occur while using a corneal flap, reduce drastically. There is also reduced risk of infection and inflammation. There is a larger treatable surface for increased stability, and thus a reduction in retreatment rates
Thinner flap:
The Femto-Lasik allows for such a thin, uniformly cut corneal flap that complications are practically non-existent. With these thinner flaps, more corneal tissue is left behind, meaning not only an increase in long-term corneal stability, but also the opportunity to correct higher refractive errors.
Even flap thickness:
When using the Femto-Lasik, the surgeon knows beforehand which form, thickness, measurements and capacity each flap entails. This is an important issue when considering treatment for higher refractive errors. When using a microkeratome, a surgeon can only know how the flap will look after the cut has been made.
Other benefits:
Eyeball measurements are of little importance for Femto-Lasik laser eye surgery. You will heal in a shorter span of time and your sight will improve much more quickly. Visual results are excellent. During the procedure, the Femto-Lasik laser exercises less pressure on the eye. This means the patient will experience very little discomfort.
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Disclaimer: The services mentioned and Photographs used are for representational and education purpose. The actual procedure & Result may vary from patient to patient. For more details on the topics and treatment plan, please consult with our experts at Bhalanetra Superspeciality Eye Hospital to know more.