Refractive Errors and Surgery (LASIK)
Myopia and treatment
Myopia, commonly known as near-sightedness or short-sightedness, refers to a condition where the patient is unable to see distant objects. Myopia is rare before the school-going age, gradually increasing during school life and reaching its peak during the intense study years of college. It is caused by many factors, with both genes and the environment playing important roles. Though it is believed that prolonged reading harms the eyes, attempts to reduce accommodative fatigue (like introducing pauses during reading and teaching, eye exercises, etc.) have not helped to reduce myopia among children.
Myopia is classified into low, moderate and high. Persons with severe myopia are liable to have vision-threatening complications and should have a dilated eye examination at least once a year.The treatment options for myopia are spectacles, contact lenses, and refractive surgery. Spectacles are inexpensive and safe and offer clear vision, relief from eyestrain and headaches, and reduced risk of developing a squint. Patients with high power are advised to use high index glasses, which are not very thick. Plastic glasses are lighter but get scratched easily.
Those who do not want to wear spectacles can opt for contact lenses, which are mainly of two types: soft and semi-soft or rigid gas permeable. Semi-soft lenses or rigid gas permeable lenses are better, because they correct more astigmatism as compared to soft lenses. For high errors of astigmatism, surgeons may suggest toric contact lenses, or soft and semi-soft lenses.Disposable lenses (daily or weekly) are discarded as indicated, while extended wear lenses can be worn while sleeping also, though this is not recommended. Sleeping or swimming with the lenses on increases the risk of corneal ulcers and infections, which are sight-threatening complications. All types of lenses should be removed at the end of the day, cleaned and soaked in the specified solution.
Hyperopia and treatment
Hyperopia refers to the condition known commonly as long-sightedness, wherein the patient has difficulty seeing objects or reading at close distances without the aid of glasses.In general, LASIK is recommended for patients with up to +4 to +5 diopters spherical of hyperopia or far-sightedness. If the error is more than +5 diopters, in young patients contact lenses are preferable to surgery. For patients above the age of 40, refractive lens exchange (along with the removal of the clear lens) with a regular monofocal/multifocal lens is recommended.
Key Points to Remember:
• Regular eye check-up is a must! As you grow, your eyes grow too. Your lens strength may need to be updated.
• If you or your child have a refractive error, all of your children should have an eye checkup
• Whatever you choose – contact lenses or glasses – you MUST take care of them properly and wear them constantly, according to the doctor’s advice.
• Vitamin A rich foods are good for eye health, but they are not a cure
• Glasses will not make your eyes stronger or weaker. They will allow you to see better with your current eyesight.
How Strong is my Lens?
The strength of the lens will depend on how much the light needs to bend to focus on your retina. Lens strength is measured in diopters. The stronger the lens, the greater the diopter. The amount of curvature in your spectacle lens will be determined by the diopter that you need.
What to choose: Glasses or Contact Lenses?
You may choose to use contact lenses if you are over the age of 15. Depending on your eye health and lifestyle, you can choose which option is more suitable. Pros and Cons of Glasses / Contact Lenses
Myopia and treatment
Key Points to Remember:
- Relatively low maintenance
- Cheaper in the long term
- While wearing glasses, you are less likely to touch or rub your eyes. This reduces the risk of infection
- Everybody can wear glasses
- Glasses protect your eyes from dust, smoke, etc.
- Glasses are available in many shapes, sizes, and colours and are often used to make a style statement!
- Side vision may be obstructed or blurred
- Glasses fog up in cold weather. Vision can also be blocked by rain
- The lens will take the shape of your eye. This gives a wider field of vision with fewer obstructions.
- Easier to exercise and play sports
- Lenses are not affected by weather. They should not fog up in the cold.
- They are less noticeable than glasses
- Require proper lens care ad cleaning. Contact lenses are in direct contact with your eye. Without proper care, you are at serious risk for infection
- They increase the risk of dry eye
- If you accidentally fall asleep with your contact lenses, your eyes will be very irritated when you wake up.
- In some specific eye conditions, it may be unsafe to use contact lenses
How to choose Glasses?
- Choose the right frame size with the help of the optician
- Plastic lenses and frames are safer for children
- Avoid glass lenses and metal frames for young children. They may injure the child if they break.
- Rimless frames are delicate and break more easily than rimmed frames
- Avoid nose pads. They may misalign the glasses and cause scarring
Glasses at Drishti Eye Hospitals
Aravind has an optical shop, where patients can select a new pair of spectacles. We have quite a large selection, with glasses for both you and your child. Please ask any of the Aravind staff if you would like more information.
Taking Care of Your Glasses
- Use both hands to wear and remove the spectacles.
- Place the glasses in a spectacle case when you are not using them. You may also place them on a clear surface, with the lenses facing up or sideways.
- Wash your glasses regularly with tap water and dry them with a soft cloth.
- Do not dry your lens with your apparels like shirt, saree, chudithar, or any other material that may scratch the lens.
LASIK (or Laser-Assisted In-Situ Keratomileusis) is the most modern surgical procedure for correcting vision problems like myopia, hyperopia, and astigmatism. Lasik is a laser eye surgery used to correct refractive errors. In this procedure, a thin laser beam is used to cut the front surface of your eye (the cornea) and change its shape. The new shape of the cornea will allow light beams to once again focus on the retina. Vision should be improved.
For adults with stable eye power, LASIK provides an alternative to glasses and contact lenses.
LASIK is an optional surgery for adults (patients should be at least 18 years of age) with stable vision. If your eye power has not changed for 1-2 years and you no longer want glasses or contact lenses, LASIK can be used to give your eyes clear vision.
Who is an Ideal Candidate for LASIK?
To be eligible, you must:
- Be at least 21 years
- Have a stable eye power for at least 1 year
- Have a healthy cornea and retina
- You should not have any ocular surface abnormality such as dry eyes.
- Your cornea should have adequate thickness for it to be operated upon.
Persons who typically opt for LASIK are those who find spectacles visually unacceptable, those who are intolerant to lenses, those who would like to participate in outdoor sports or opt for professions demanding excellent uncorrected vision.
However, though doctors strive to make the refractive error zero after LASIK, this may not always be possible. The main purpose of surgery is to offer sufficient good vision to patients so that they are not dependent upon glasses most of the time. Some of the possible side effects of LASIK are undercorrection, overcorrection, glare, halos, and reduced contrast sensitivity. Therefore patients must have a detailed eye examination before surgery, followed by a realistic discussion with the surgeon on the expected outcome of surgery.
Defects or aberrations that can be corrected with LASIK
Myopia or short-sightedness occurs when light rays are focused in front of the retina causing blurred vision, particularly when viewing distant objects. Objects that are near may be seen clearly, but not those that are far away. Myopia is often hereditary, usually due to an abnormally large eyeball or steeply curved cornea. Because the eyeball grows with age, myopia tends to progress, usually stabilizing by the time the person is 20 years old.
Hyperopia or far-sightedness is the opposite condition of myopia, where the light rays converge at a point beyond the retina. Initially objects that are near seem blurred, though distance vision remains clear. However, with age, objects at all distances become blurred.
Astigmatism is an irregularity in the shape of the normally spherical cornea. The cornea is shaped like an egg or the back of a spoon, causing distortion of both distant and near vision.
Why would you be interested in LASIK?
- You do not want to wear spectacles or contact lenses.
- You feel visually and socially restricted by spectacles or contact lenses.
- You are intolerant to contact lenses.
- You want to participate in certain outdoor sports where using spectacles or contact lenses may be a problem.
- You plan to join certain professions wherein excellent uncorrected visual acuity is a prerequisite.
Before the laser procedure?
The patient undergoes a normal eye examination after which the ophthalmologist may suggest a vision corrective procedure. Thereafter, information about the patient’s eye structure and function – including corneal thickness, corneal curvature, optical aberrations etc. – will be ascertained. This is done at Drishti Eye Hospitals by the latest diagnostic equipment. The eye test reports are studied by the ophthalmologist before making a final decision, in consultation with the patient.
What to expect during laser surgery?
At Drishti laser surgery is done on an out-patient basis; this means you go home immediately after surgery. A relative or friend, who can take you home after the surgery, should accompany you. Usually, one eye is treated at a time. The procedure is performed under topical anaesthesia.
- Is a simple and safe surgery
- Causes almost no pain or discomfort
- Leaves no scar
- Has fast recovery periods
- Has very few complications
- Can be enhanced, if necessary
However, please keep in mind that the surgery may not correct your vision 100%.
After the surgery, you may still need to wear spectacles of a lower power. Please discuss all concerns with an eye doctor before deciding on LASIK.
Types of LASIK:
- PRK (Photo Refractive Keratectomy): Usually advised for patients with very weak power
- Standard vs Personalized LASIK: Both reshape the cornea to correct the refractive error. The standard laser applies a uniform correction to the entire reshaped area. In personalized LASIK, measurements are taken from the entire eye to create a customized map of your refractive error. The laser is used to apply a correction specifically for your refractive error.
- FEMTO: Blade-free LASIK. The cornea is not cut manually, but by a special laser machine.
Preparing for Surgery:
You will need to complete a few things before your LASIK surgery.
You will need to get a pre-surgery eye examination to make sure you are fit for the surgery. This examination typically takes 4-5 hours and can be done at Aravind on any working day. The best time to come is at 8 am. Based on the examination, around 70% of patients will be approved for LASIK surgery. The remaining 30% are ineligible and cannot have the surgery.
You should NOT wear contact lenses for a minimum of 7 days before coming for the pre-surgery exam
When deciding if LASIK is right for you, keep in mind that there is no absolute guarantee that it will correct your vision 100%. You will see much better without glasses than you did before. But, you may still need to wear glasses at times to perform certain tasks.
After the surgery, your eyes may itch and water. Vision will also be blurry. Keep in mind that your eyes are still healing, so it will take time (about 2-3 months) for the vision to clear completely.
For a few weeks after surgery, you should avoid:
- Contact sports
- Swimming in pools or hot tubs
The doctor will tell you if and when it is necessary to come for a follow-up visit.
Results – How good will my vision be?:
LASIK is intended to provide clear vision without glasses or contact lenses. Most patients who get LASIK will have very good vision and will not need to wear spectacles. However, the results may vary from person to person. LASIK does not guarantee a 100% correction of vision. If your refractive error is very severe, your vision may not improve as well as expected. However, it will likely be better than it was before surgery.
Your vision will become clear within a few days. Sometimes you may require another round of treatment with laser, particularly with higher degrees of refractive error.
Although LASIK is an excellent procedure for low and moderate refractive errors, it may not totally remove the need for using glasses in everybody. However, it definitely decreases the dependence on glasses for day to day work.
Risks & Complications:
Laser surgery is very safe and effective. But in some patients there could be side effects. Your doctor at Drishti Eye Hospitals will be happy to discuss these with you and clear your doubts before surgery.
After surgery, you may have dry eyes or occasional blurry vision for a few weeks. Long term complications are very rare. They include:
- Glare or rings around bright lights
- Double vision
- Watery eyes
- Under-corrections: Under-corrections are unpredictable. But when they occur, they may not give the clear vision you expected. This can be fixed with another LASIK procedure.
- Your vision may not be as clear as anticipated.
- Astigmatism: Though uncommon, astigmatisms are another possible complication. You may need another surgery to correct the condition.
If you have a corneal eye disease, severe near-sightedness, or age-related eye diseases, LASIK is not advisable. The same goes for people who play contact sports or work in areas that increase the risk of eye trauma. If you have good vision without spectacles, there is no reason for you to get LASIK.
Alternatives to LASIK
For patients where the corneal thickness is not sufficient for doctors to perform LASIK, there are other alternatives. (Generally we do not do LASIK if the thickness is less than 470µm for spherical errors and less than 490µm for cylindrical errors). In such cases the options are:
- Photorefractive kertectomy (PRK)
- Phakic intraocular lens
- Clear lens extraction (Refractive lens exchange) with negative intraocular lens implantation
- Astigmatic cataract surgery and multifocal lenses
A new technique, SMILE produces virtually the same visual acuity as LASIK for the correction of nearsightedness, without the need to create a LASIK-style corneal flap.
We are planning to offer this option at Drishti Eye Hospitals in the near future.
For more Information, Kindly schedule an appointment with one of our Experienced Ophthalmologists at Drishti Eye Hospitals in Hyderabad who will guide to making the right choice for you.
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