Follow Us on Social Media

HomeEye OverviewRefraction Errors & Correction

Refraction Errors & Correction

Slight alterations in vision should never be neglected. It’s very important to get yourself checked by trained optometrists and specialist and get your eyes evaluated. Uncorrected refractive errors can lead to impaired development of vision in children leading to amblyopia or lazy vision and squinting of eyes.

Refractive errors in the eye are of 3 types

Myopia or short-sightedness

Refers to a state of the eye, wherein the rays of light coming from a distant target, get focused at a point in front of the retina. In this situation, minus powered glasses or contact lenses are necessary to focus this image onto the retina.

 Hyperopia or long-sightedness


Refers to a state of the eye, wherein the rays of light coming from a distant target, get focused at a point behind the retina.

In this situation, plus powered glasses or contact lenses are necessary to focus this image onto the retina.

Astigmatism or cylindrical power


Refers to a state of the eye, wherein the rays of light coming from a distant target, cannot focus at a single point on the retina. In this situation, special lenses of different curvature are required to focus the light onto the retina.

Various methods to correct refractive errors

Spectacles Contain lenses that alter the incoming rays of light to enable them to focus on the retina.

Contact Lenses perform the same function as spectacles but are placed in the cornea. They provide improved cosmesis and better quality of vision, especially for higher refractive errors.

In the Apollo Eye clinic trained optometrists to perform refraction aided with autorefraction, keratometry and corneal topography. Contact lens fitting is done for both soft and semi-soft lens.

Refractive errors can be corrected through surgery

LASIK is an exciting surgical procedure that is capable of correcting a wide range of nearsightedness (myopia), farsightedness (hyperopia) and astigmatism. LASIK is the acronym for laser-assisted in-situ keratomileusis. The name refers to the use of a laser to reshape the cornea without invading the neighbouring cell layers. Lasik is currently the most commonly performed refractive procedure in the United States and in India. Lasik has been performed internationally for approximately 10 years.

It was first performed in clinical trials in the US in 1991. It was officially approved in 1996 in the U.S. It is important to note that the major components of the procedure have a long history. Ophthalmologists have been reshaping the cornea for over 50 years creating a protective layer of tissue for over 35 years and using the excimer laser since the 1980s.

Photo Refractive Keratectomy (PRK)

In this procedure, the laser treatment is directly performed on the surface of the cornea to
reshape it for correction of refractive errors. This is usually performed for people with smaller refractive errors. The surface layer usually takes 3-4 days to heal and the vision gradually improves thereafter.

Laser in Situ Keratomileusis (LASIK)

This procedure involves first creating a thin flap of the cornea with an instrument called the microkeratome. Followed by the lifting of the flap and laser treatment to reshape the cornea. The flap is then repositioned in its original place. Improvement in vision is noted right from the next day.

The beam profile of Wave light laser has been wavefront-optimized, hence it removes a lesser amount of corneal tissue when compared to other laser machines, thus making the treatment safer for your eyes. Wavefront optimization also ensures that you do not experience any

glare or halos during the night while looking at bright lights. Wavelight laser allows multiple options for customized treatments, such as wavefront-guided, topography-guided, Q factor guided treatments. Such treatment modalities are far superior when compared to those with other lasers such as zyoptix, custom vue, or custom cornea.

Both PRK and LASIK procedures are absolutely painless and are performed as an outpatient procedure using topical anaesthetic eye drops. The entire procedure lasts for only 10 –15 minutes and you will be awake during the entire procedure. During the treatment, you are required to look at a fixation light while the laser is performed and you will also hear the noise of the laser machine during the treatment.

The actual laser treatment only lasts for 15 to 45 seconds. Following the treatment, you can return home immediately. However, you should make arrangements for a friend or relative to take you home after the procedure.

After going through our site there will be many doubts rising in your mind. We have tried to answer a few general questions for more details you can contact us we will be more than happy to be of assistance to you

  • Am I eligible for LASIK?
  • While most patients are eligible for LASIK, not everyone is.
  • An ideal candidate for refractive surgery?
  • Must be at least 18 years of age with stable refraction for 1 year.
  • No associated eye diseases.
  • No connective tissue disorders.

Must discontinue contact lens wear 2 weeks prior to refractive surgery. Eligibility also depends on the number of refractive errors, the curvature and thickness of the cornea and a number of other factors that an ophthalmologist must evaluate. Proper patient selection is vital for successful refractive surgery and a satisfied patient.

Will my vision improve immediately?

There is a considerable improvement in unaided vision following the treatment. Following PRK the vision improves 3-4 days later once the surface healing incomplete. Following LASIK this improvement is noted right from the next day. However, a slight fluctuation of vision may occur over the next few months as the healing process continues.

What are the possible side effects?
Usually, most patients are quite comfortable following LASIK. There is a moderate amount of pain following PRK on day 1, which reduces subsequently. There may be transient light sensitivity, glare & foreign body sensation, or dryness in the treated eye. Sometimes there may be a slight under correction or over correction following the procedure.

What are the possible side effects?
Usually, most patients are quite comfortable following LASIK. There is a moderate amount of pain following PRK on day 1, which reduces subsequently. There may be transient light sensitivity, glare & foreign body sensation, or dryness in the treated eye. Sometimes there may be a slight under correction or over correction following the procedure.

Will I need to wear glasses or contact lenses after the procedure?
Both PRK and LASIK are designed to allow you to discontinue the use of corrective lenses for routine daily work. In some patients with higher refractive errors, corrective lenses of lower power may still be required following the treatment. In some individuals, this residual refractive error can be corrected by a second refractive procedure

When can I resume normal activities?
You can return to work after 3 days if PRK has been performed. Following LASIK you can return to work the following day. While most activities can be resumed, it is better to avoid swimming, contact sports etc at least for a one-month duration.

Are the results of LASIK permanent?
LASIK permanently removes corneal tissue to reshape the eye in order to improve refraction. The physical results are permanent. However, you should be aware that since the eyes can still change with time, LASIK does not prevent presbyopia or affect this condition once it does occur.

Should I undergo LASIK?
Ophthalmologists all over the world have been reshaping the cornea using the excimer laser since the 1980s. LASIK has been performed internationally for approximately 10 years now. While refractive surgery does not promise perfect vision, it does hold the promise of reducing one’s dependence on contacts or glasses. For many people, the reduction will allow them to more freely pursue their hobbies, sports activities or career options.

Other Options of Refractive Surgery 
Phakic IOL implantation


Higher degrees of refractive errors often cannot be corrected by laser refractive surgery, in these patients, implantation of special implants such as phakic intraocular lens (Veriseye) allows correction of refractive errors with good unaided vision post-surgery

Astigmatic Keratotomy


Using a diamond knife, incisions can be placed on the cornea to correct astigmatic refractive errors (cylindrical power).

Refractive lens exchange


Very high refractive errors can be corrected by replacing the natural crystalline lens with new generation intraocular lens (Wavefront optimized anterior surface multifocal lens and posteriors square edge IOL’s) i.e. refractive cataract surgery).

Cataract Surgery

Cataract or clouding of the natural crystalline lens can be corrected surgically by removing the cataract and replacing the same with an intraocular lens (IOL) implant. Ultrasound A-Scan and keratotomy tests are used for accurate IOL power calculation.

The cataract is removed with phacoemulsification, a technique wherein ultrasonic energy is used to break and emulsify the cataract followed by removal. All this performed through an incision size of just 2.75mm. Our phaco machine, AMO Sovereign, with new white star technology allows cold phaco (minimal build-up of heat during cataract surgery)

that is much safer for the eye compared to conventional phaco machines. IOL selection is customized for each individual to ensure the best visual outcome. The surgery is painless and patients can return home the same day.

Call Us Now08069991035 Book ProHealth Book Appointment

Request A Call Back

Close