About Refractive Errors:

Glasses (or spectacles) and contact lenses are two of the most common ways of correcting refractive errors. In eyes with normal vision, light focuses on the light-sensitive retina at the back of the eye. Once the retina senses light, it converts the light into the image that you see.

In refractive errors, the eyes are unable to focus light on the retina. This results in blurred vision. The solution is glasses or contact lenses. These bend the beam of light so it focuses properly on the retina. This should restore clear vision.

Normal vision: In normal vision, light rays from an object focus on the retina.

Refractive error: A refractive error is when the light rays focus either in front of or behind the retina. This causes blurred vision.

Types of Refractive Errors:

The four most common types are:

Short-Sight (Myopia)

Close objects look clear, but distant objects are blurry. This happens when light focuses in front of the retina because the cornea is too curved or the eye is too long.

Long-Sight (Hyperopia)

Distant objects look clear, while nearby objects look blurry. Sometimes, this can be hard to notice. In extreme cases, objects are blurry at any distance. Hyperopia is when light focuses behind the retina because the eye is too small.


With this disease, light focuses unevenly on the retina. This distorts the image and makes it blurry. It is due to changes in the curve of cornea.


Presbyopia is a natural part of ageing. Over time, the lens in your eye loses its ability to change shape. Light cannot focus as well as it did before, so nearby objects look blurry.

Risk Factors:

Near-sightedness, far-sightedness, and astigmatism can occur at any age. The risk of presbyopia increases with age. Adults older than 35 are most commonly affected.

Those with a family history of refractive errors are at a greater risk.

The most common sign is blurry vision. Other symptoms include:

  • Double vision
  • Difficulty reading
  • Seeing rings around bright lights
  • Squinting or squeezing your eyes to see better
  • Headaches
  • Eye strain

The three main treatments are Spectacles, Contact lenses, and LASIK Surgery . In all cases, follow-up treatment may be necessary.

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



    • 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

Contact Lenses:


    • 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 Aravind

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.