Eye Care Q & A: Getting Your First Glasses or Contacts
Sight is probably the most important of all the senses. People with imperfect eyesight need glasses or contact lenses to help them see clearly.
Q: What are the Signs of Eye Problems?
A: If you are having trouble reading letters beyond a distance of 10 feet in normal light, it’s almost a sure chance that you need glasses. The eyes are designed to focus the light coming from an object on the retina located at the back of the eye. The lens of the eyes is very flexible and it can adjust the light coming in from a distant object. The lens helps to focus the light on the retina perfectly so that you can see the image. If the eyes are affected, the muscles which normally relax and contract in a healthy eye cannot function as intended. This is when people start to have difficulty seeing objects either at a distance or close by. These various conditions have different names assigned to them and they demand different types of glasses to correct the condition.
Q: What are Near-Sightedness and Far-Sightedness?
A: The eye muscles or ciliary muscles are normally flexible in a healthy eye. They contract and flex depending on the distance the light is coming from. In an eye where the muscles are affected, they cannot contract and relax so the light cannot be focused onto the retina causing either myopia or hypermetropia. Myopia (nearsightedness) is a condition in which the person cannot see properly beyond a distance. Hypermetropia (farsightedness) is a condition in which the vision is limited to seeing objects at a greater distance and the person cannot see properly at a close distance. In all these conditions, glasses are prescribed to correct the vision.
Q: What is Astigmatism?
A: Astigmatism is a condition which is due to the incorrect shape of the cornea. In a healthy person, the cornea is shaped like a sphere. If the shape deviates, the light gets refracted (bent) in different directions which cause it to land in different positions on the retina. This causes a blurry image of the object.
Q: How Do Contact Lenses and Glasses Work?
A: Contact lenses and glasses are used to correct the problems of farsightedness, nearsightedness, and astigmatism. All conditions of hypermetropia, myopia, and astigmatism are conditions in which the lens of the eye cannot focus the light correctly. Both glasses and contact lenses work by focusing the light on the retina correctly. Glasses can be either concave or convex. Concave lenses are used for correcting the problem of myopia. These glasses are thin in the middle and thicker around the edges. For hypermetropia, convex lenses are used. These glasses are thick in the middle and thin around the edges. For astigmatism, the glasses are more curved in one direction than in the other. They are used for correcting the problem of astigmatism or irregular shape of the cornea.
Contact lenses are used as an alternative to wearing glasses and they function in the same way as glasses to correct the problems of hypermetropia, myopia, and astigmatism. Unlike glasses, contact lenses are worn directly on the cornea of the eye. There are various types of contact lenses available like:
- Rigid gas permeable lenses
- Rigid contact lenses
- Water absorbing lenses
- Non water absorbing soft lenses
Wearing contact lens can result in lack of oxygen to the eyes, resulting in redness and infection. Other problems can be inability to have them removed on their own, blurring vision due to the lens getting worn out, and also irritation due to improper fitting. Some lenses like the overnight lenses are recommended to be worn for about 1 week and then replaced by a new lens.
Q: What Do the Numbers on Prescriptions Denote?
A: You may have noticed the letters RE or LE on prescriptions. Some ophthalmologists would prefer using OD or OS instead. OS (Oculus sinister) or LE means the left eye, whereas OD (Oculus dextrous) or RE means the right eye. Usually the LE or the OS is denoted by a (-) sign and the RE or OD is denoted by a (+) sign.
Q: What Types Of Glasses Fit Which Face Shapes?
A: Not all types of glasses fit all face shapes. To find the best glasses for your face shape, follow these simple guidelines:
- The frame and glass shape needs to fit the shape of your face.
- Ensure that they enhance the best features of your face.
- The frame should be of the same scale as your face. The five common face shapes are oval, round, oblong, heart, and square.
Q: How Do I Care For Contacts and What Are the Different Kinds?
A: There are various types of contact lenses available ranging from daily disposable lenses, to biweekly and monthly disposables to conventional lenses that you can use for a year.
Before handling your lenses, wash your hands with soap, and ensure that you dry them with towel. Don’t let water come in contact with the lenses. They should never be cleaned in water. Not all saline solutions and rewetting drops are ideal for disinfecting lenses. It’s best to use specially recommended solutions for cleaning your lenses. This prevents your cornea from getting infected, which may cause problems. Never touch the tip of the disinfecting solution bottle, it can contaminate the contents. Ensure that you wear the lenses only for the duration they are recommended.
Q: What are the Different Types of Glasses?
A: Convex and Concave- Convex lenses are thicker in the middle and thinner on the edges. Both or one of the surfaces can be curved outwards. Concave lenses are curved inwards. They are thinner in the middles with thicker edges. These lenses refocus the light from the front of the retina to the back of the retina to ensure that the affected person can see properly.
Photochromatic - Photochromatic lenses are designed to react to light and turn darker. Modern plastic photochromatic lenses are designed to not only block the UV lights, but also prevent the wearer from the harmful light of a computer screen.
Varifocals - Varifocals are the modern day solutions for bifocals which are slowly becoming obsolete. They have no distinguishing lines and smoothly transition from one region of the correction to the other without any problem.
Q: How Do I Clean My Glasses?
A: Always use a soft cloth to clean your glasses. You can also use warm water and then dry it with a soft cloth. If you spend a few minutes to clean your glasses, they can serve you for years.
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