Refractive Errors: Types and Treatments

Refractive Surgery

Refractive Surgery: Types of Treatment And Risks

Refractive Surgery refers to any surgical procedure used to fix vision problems. It is also known as Vision correction surgery and laser eye surgery because most of these surgeries are performed with the help of laser. Refractive and laser eye surgery allow patients to get back their 6 by 6 vision. If you have any refractive error, such as Myopia (nearsightedness), Hyperopia (farsightedness), Astigmatism, or Presbyopia. Refractive Surgery is the method for correcting or improving your vision. These surgeries are basically performed for specs removal.


Types of Refractive Errors

The Refractive Errors are usually addressed through prescription eyeglasses or lenses. Refractive surgery treats these conditions and eliminates or reduces the need to use glasses or lenses.


Myopia (Nearsightedness)

Nearsightedness is a common eye disease, in which the image of a distant object becomes focused ahead of the retina, instead of on it. It happens either because the refractive power of the eye is too strong, or because the eyeball axis is too long. It makes distant objects appear blurry and out of focus. This condition may cause headaches and/or eye strain.

Eyeglasses or contact lenses are prescribed to help correct myopia by adjusting the focusing power to the retina. For some patients, correct refractive surgery may also help by changing the shape of the cornea. surgery reshapes the cornea to a more spherical, round shape and reduces the curvature of a cornea. This way the eye’s focusing power is reduced. Images that are focused ahead of the retina, are pushed closer to or directly onto the retina after the refractive surgery.


Hyperopia (Farsightedness)

 Commonly known as farsightedness, hyperopia is the opposite of myopia. It is also a common refractive error in which an image of a distant object becomes focused beyond the retina. Making close objects appear out of focus. This happens either because the refractive power of the eye is too weak, or because the eyeball axis is too short.

People with Hyperopia will have refractive surgery that makes the cornea steeper and increase the eye’s focusing power. Images that are focused behind the retina, will be drawn closer to or directly onto the retina after surgery.



 Presbyopia is another type of farsightedness. It is caused when the centre of the eye lens hardens. This makes it unable to see nearby objects. This is typically an age-related condition. It eventually affects almost everyone from 35-40 onwards. It may even affect patients who have myopia. Eyeglasses or contact lenses may be prescribed to correct or improve the condition. But surgery is the permanent cure to presbyopia.




Astigmatism is when objects up close and at a distance appear blurry. It is caused by an abnormal curvature of the cornea that makes two focal points fall in two different locations. Astigmatism may cause eye strain and may be combined with myopia or hyperopia.

It can be corrected with refractive surgery. It reshapes selected parts of an irregular cornea to make it smooth and symmetrical. With the result that images focus clearly on the retina.



Types of Refractive Surgery

There are several surgical procedures for correcting or adjusting the focusing ability of the eye by reshaping the cornea. There have been huge advances in recent years in the field of eye surgeries. And most types of vision correction surgery reshape the cornea. This lets light travel through it and focus properly on the retina. Other procedures replace the natural lens of the eye with an artificial lens.

The main types of refractive surgeries use a laser or an artificial lens. These are explained as:


 LASIK,  or laser in-situ keratomileusis, works for people who have MyopiaHyperopia, or Astigmatism.

The best Eye Doctor in Delhi will reshape the underlying corneal tissue to focus light on the eye and reach the retina. In the surgery, a flap will be cut in the outer layer of the cornea to get to the tissue underneath. Then underneath tissue is exposed to laser beams.

What makes LASIK surgery different from other procedures is its methodology. It creates a flap of the outside layer of the cornea to access the underlying tissue. The surgery requires precision, calmness, and focus. Various advancements in computer imaging wavefront technology are really helpful. It allows LASIK specialists to generate detailed images of the cornea and guide the treatment.


PRK (Photorefractive Keratectomy)

 PRK is a procedure that uses a laser to sculpt the surface of the cornea. It’s ideal for correcting mild to moderate nearsightedness, farsightedness, or astigmatism. PRK can also work with computer imaging technology. Unlike LASIK, PRK only affects the surface of the cornea, not the tissue underneath. Your doctor may also use computer imaging of the cornea. Before the laser can do its work, a blunt microkeratome is used to remove the epithelial layer of the cornea.

Nowadays an advanced technique has evolved, known as Surface Ablation. It cools the cornea before and after the surgery to reduce the discomfort the patient may experience. You may be given a special contact lens to act as a bandage to facilitate the healing of the epithelial layer. The healing usually takes around 4 days. Antibiotics, anti-inflammatory medication, as well as pain killers, may also be prescribed.


LASEK (Laser Epithelial Keratomileusis)


 This surgery is a slight variation of PRK and LASIK. Your Eye Doctor will create a flap during the surgery. Under LASEK a trephine blade is used, which is much finer than the one used in LASIK, to make the flap. An alcohol solution is used to loosen and lift the epithelial cells. After this, an excimer laser sculpts the cornea through ablation. And the flap is set and secured with a soft contact lens so that it can heal.

The complete process takes about 15 minutes for one eye. The recovery takes around 4-7 days. Vision improves within 6-8 weeks.

LASEK treats nearsightedness, farsightedness, and astigmatismLASEK is a great choice for people who have less corneal tissue. Because compared to LASIK, LASEK possesses less risk of causing Dry Eyes and causes no stromal trauma.


Phakic Intraocular Lens Implants

 Phakic intraocular lens implants are designed for patients who are too nearsighted for PRK or LASIK. For this surgery, the doctor makes a small incision at the edge of the cornea, first. Then he/she would either attach the implant lens to your iris or insert it behind your pupil. Unlike RLE, the natural lens of the eye is left in place. Visian ICL is the main type of phakic lens implant used.


Limbal Relaxing Incisions (LRI)

Limbal relaxing incisions are made on the cornea to treat astigmatism. When you have astigmatism, the eye protrudes, like a football, instead of being round. Astigmatism is caused by corneas that are either too elongated in one axis and too flat in another. The doctor makes one or two incisions at the steepest part of the cornea. Or the Limbus, the junction between the sclera and the cornea. This helps it deflate and makes it more rounded.

The procedure required very precise planning on where the cuts will be made. It doesn’t use lasers. Despite all that, the procedure is rather painless and eliminates the need for distance glasses.

This procedure can be done as a standalone, or with other laser eye surgeries like PRK and LASIK.


RLE (Refractive Lens Exchange)

Other names include Clear Lens Exchange or Extraction (CLE), and refractive lens replacement (RLR). The procedure in this refractive surgery is the same as cataract surgery. The doctor makes a small incision at the edge of the cornea. Then removes your natural lens and replaces it with an artificial lens implant.

This surgery can correct severe farsightedness or nearsightedness. It is ideal for people who have thin corneas, dry eyes, or other minor cornea problems. RLE can be undertaken along with a LASIK or LASIK-related procedure to correct astigmatism.


PRELEX (Presbyopia Lens Exchange)

This refractive surgery is performed on patients with presbyopia. Presbyopia, as explained above in the blog, is when the eye’s lens loses its flexibility. Patients with presbyopia have difficulty focusing on close objects, such as reading or threading a needle. PRELEX is a method where the Eye Doctor implants a multifocal lens to improve flexibility and recover focus.


ICR (Intracorneal Ring Segments)

It is also known as Intacs. The doctor cuts a small incision in the cornea and plants two crescent-shaped plastic rings at the outer edge. The rings help to flatten the cornea and change the way light rays focus on it. ICR was, earlier, used to treat nearsightedness, but has been replaced by advanced laser-based procedures. Now it’s used to treat keratoconus, a condition of an irregular-shaped cornea that causes the cornea to thin out and results in vision loss.


Radial Keratotomy (RK)

Radial keratotomy surgery is performed to improve or remove nearsightedness. This is done by making small incisions in the cornea to flatten it. If you also have astigmatism, you may need more incisions.

The surgery can take between 10 to 15 minutes, per eye. But generally, the other eye is operated on after waiting for around 6-weeks, to prevent infection and strain. Recovery will take a few days. Meanwhile, you may have to make frequent visits to the surgeon after the surgery.

With recent advances in refractive surgery, such as LASEK and PRK, RK is not much common now. Among patients as well as Ophthalmologists.


ALK (Automated Lamellar Keratoplasty)

ALK can help people with extreme nearsightedness and some farsightedness. For this procedure, the Eye Doctor creates a flap in the cornea to access the underlying tissue. She will make an incision in the sub-layer of the cornea to reshape and correct vision. No laser is used. However, nowadays, LASIK has replaced ALK as a method of correction.


Risks of Refractive Surgery

The good results of the above-listed refractive surgeries are well-researched and documented. But like all surgeries, there can be some side effects. It’s essential to keep them in mind. some of these risks could be:

  • Infection and delayed healing

Some people may get infected after PRK or LASIK. It generally means a longer healing process and added discomfort. Sometimes the effects of surgery go away over a period of few months after healing. A second surgery may be required to improve your vision.

  • Under-Correction or Over-Correction

You may still need glasses or contacts after the surgery. There is no way to assess how well the surgery worked until the eye has healed suitably. If your eyesight and vision haven’t improved much, a second laser surgery, called laser enhancement, can help.

  • Worse Vision

It’s quite rare, but the vision for some people gets worse than before the surgery. Excess corneal haze or irregular tissue removal are the usual culprits.

  • Excess Corneal Haze

This can be a part of the natural healing after PRK surgery. It can only be seen through an eye examination. It usually has no effect on the vision. If it does affect your vision, you may need a second procedure. Also, a medicine called mitomycin C (MMC) during PRK surgery has proved effective in its prevention.  A hinged flap is created under LASIK on the center of your cornea. It may need to be repositioned within the first few days following the surgery or after a severe direct eye injury.

Refractive surgery has evolved beyond simple laser refractive techniques over the past few years. Laser refractive surgery procedures, surface ablation techniques, and PRK is now established as safe and convenient procedures that produce excellent visual outcomes for patients with low-to-moderate amounts of Refractive Errors. Additionally, a wide variety of options is now available to treat the extensive range of these errors.

Small Incision Lenticule Extraction (SMILE) uses a femtosecond laser to shape a refractive Lenticule, which is removed through a small wound. The advantages of this procedure include better tectonic strength and less dry eye. In the coming days, intracorneal (ICL) implants could be used to treat hyperopia or presbyopia.

Thus, eye surgeons have now quite good options to provide patients with the appropriate refractive correction based on their condition.

There is no best method for correcting refractive errors, that has been universally accepted. The best option for you should be decided and discussed after a thorough examination with your Eye Doctor.



If you are considering refractive surgery, consult Eye Mantra Now. There you can discuss your lifestyle and vision to determine the most appropriate procedure for you.

Call Now at +91-9711115191 to book an appointmentOr mail us at [email protected].

Our other services include Cornea SurgeryGlaucoma SurgeryComputer Vision Syndrome, and many more.


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