|
Frequently Asked Questions
1. What is shortsightedness?
2. What is long-sightedness?
3. What is astigmatism?
4. When should my child have his/her first eye examination?
5. How often should I have my eyes tested?
6. What are cataracts?
7. What sorts of symptoms can indicate an eye problem in my child?
8. What happens during an eye examination?
9. What can an optometrist offer me?
10. What is a lazy eye?
11. What normal vision changes can I expect with age?
12. Why do most people over the age of 40 need reading glasses?
What is shortsightedness?
Shortsighted people do not see distant objects clearly. The eye normally focuses light into an image on the retina. In a shortsighted eye the light reaches a focus in front of the retina and so the image on the retina is blurred. Your optometrist calls shortsightedness myopia. Common symptoms include squinting and difficulty distinguishing details on the blackboard, road signs and scoreboards. Myopia is easily corrected with either contact lenses or spectacles.
What is long-sightedness?
The eye normally focuses light into an image on the retina. In a longsighted eye, the light is not yet focused when it reaches the retina and so the image reaching the retina is blurred. Your optometrist calls long-sightedness hyperopia. Slight hyperopia is not usually a problem because the lens compensates easily by exerting some extra focusing, providing a clear image on the retina once again. The greater the amount of hyperopia however the harder it is to maintain a clear focus and this can lead to symptoms of eyestrain. While vision may be clear in the distance it tends to become blurry for close objects, because the closer the object, the more focusing required. Typically, hyperopic people get tired eyes or headaches after extended periods of close work, even if their vision is clear. Prescription spectacles often work to relieve these symptoms of eyestrain and blurry near vision.
What is astigmatism?
Astigmatism occurs when the surface of the eye is not perfectly spherical. To use an anology – instead of being shaped like a soccer ball it is shaped more like a rugby ball. In order to create a sharp image the eye requires a single point of focus on the retina. In an eye without astigmatism the curvature of the surface is identical in all directions measured. Therefore light entering the eye is focused the same amount in all different directions of entry and creates a single point of focus which in turn creates a clear image if located on the retina. In an astigmatic eye (like a rugby ball) there are two different curvatures on the surface one being steeper and the other at right angles to it, is shallower. Therefore depending on which direction the light enters the eye from, it will be focused at 2 separate points. The eye can only create a sharp image if it receives a single focus point. As such, an astigmatic eye receives a blurry image. Objects at all distances are indistinct or blurred and the eye cannot focus. Even slight degrees of astigmatism may cause headaches, fatigue and reduce concentration. This is because the eyes may try without success to correct the blur. Spectacles and contact lenses can correct astigmatism.
When should my child have his/her first eye examination?
Normally at birth your child’s eyes are examined by a paediatrician , for signs of major defects as part of the routine post-partum examination. This examination is extremely important because the earlier defects are detected, the greater the likelihood of effective treatment. Although initially your child may have no signs of eye or vision problems difficulties may develop later. It is therefore essential that a child should be examined by an optometrist before reaching school age. Should you have any concerns about your childs eyes or vision you should consult your optometrist as early as possible. The earlier a problem is detected and diagnosed the greater the likelihood of successful treatment, minimizing any permanent vision damage.
How often should I have my eyes tested?
Normally your eyes should be examined by an optometrist at least every 2 years even if you don’t wear spectacles. There is much more to a healthy set of eyes than just clear vision. When an optometrist examines your eyes not only will the clarity and comfort of your vision be assessed but also the general health of your eyes will be checked. For certain conditions (eg. contact lens wearers or patients with cataracts) your optometrist may wish to see you more frequently and will inform you as such. Many of the changes caused by eye disease occur slowly, and sometimes without obvious signs or symptoms. Regular check ups make detection more likely, enabling prompt treatment with a better chance of preventing any further damage or vision loss.
What are cataracts?
Cataracts occur when the lens inside the eye becomes cloudy. This cloudiness interferes with the light entering the eye, resulting in poor vision. Most cataracts are the result of the ageing process and exposure over time to UV light. Some are caused by injury, exposure to certain chemicals or particular systemic diseases. Occasionally a baby will be born with cataracts and this may be due to the mother’s illhealth during pregnancy or due to genetic defects. Most cataracts progress slowly, and result in a gradual deterioration in vision over time. If untreated however, cataracts can cause blindness. The good news is that cataracts can be easily removed surgically. Early detection is therefore crucial in avoiding blindness.
What sorts of symptoms can indicate an eye problem in my child?
- One eye turns in or out while the other points straight ahead
- Tilts head noticeably when looking at things
- Covers or closes one eye when reading
- Screwing up eyes while watching television
- Does not recognize familiar people in the distance
- Blinking frequently
- Eyes are often red
- Watery eyes
- Sensitivity to light
- Frequently rubbing eyes
- Burning or itchy eyes
- Close reading distance
- Poor concentration span
- Losing place when reading
- Skips or confuses words when reading
- Frequent headaches
- Blurred or double vision
- Slow at learning to read
What happens during an eye examination?
When an optometrist examines your eyes, the clarity and comfort of your vision as well as the general health of your eyes will be checked. After discussing any symptoms you may be experiencing, your optometrist will determine whether you need prescription lenses. Your optometrist will also test whether your eyes are working together efficiently and also assess your ability to focus on close objects. Using a slit lamp microscope the cornea, conjunctiva, iris, lens and lids will be inspected. The optometrist will then use an ophthalmoscope to examine the inside of the eye including the lens, the retinal blood vessels and the optic nerve head. The appearance of these tissues can indicate problems involving the eye, for example cataract or glaucoma, or other diseases such as high blood pressure or diabetes. Sometimes medication will have side effects that disturb vision. Assessments of intraocular pressure, fields of vision and colour vision may also be done. If your optometrist finds any sign of eye disease or general health problems, arrangements can be made for you to see an eye doctor (ophthalmologist) or general medical practitioner.
What can an optometrist offer me?
Your optometrist offers comprehensive vision care and will help you to obtain the best from your vision. It is important to have your eyes examined regularly. The sooner eye health and vision problems are discovered the sooner you can be helped. Your optometrist is qualified and registered to:
Examine your eyes for vision disorders
Prescribe, supply and repair spectacles
Detect and diagnose signs of health disorders involving the eyes
Prescribe and supply contact lenses
Analyse and treat eye co-ordination disorders
Prescribe other specialised optical aids
Advise on lighting
What is a lazy eye?
A lazy eye occurs when there is reduced vision in one eye compared with the other. Your optometrist calls this condition amblyopia. It usually results from poor eye co-ordination, a turned eye or one eye requiring a far greater vision correction. The reduced vision occurs because the eye in question is being used less than the other. When detected early enough, patching, vision training and lenses can help to reverse or prevent permanent damage to the vision.
What normal vision changes can I expect with age?
Most eyes are long-sighted at birth. This usually reduces as the eye grows to full adult size during adolescence. It is then, in the teens that short-sightedness tends to develop if at all. After relatively stable period in the 20’s and 30’s another significant time for change begins in the 40’s. This involves a gradual loss in the ability to finely focus with the lens inside the eye. The result is a totally normal and expected change called presbyopia which continues into the early 60’s. During this period it is normal to require spectacle prescription changes every 2-3 years.
Why do most people over the age of 40 need reading glasses?
In order to focus on objects up close, the lens inside the eye needs to change its shape to become fatter and bring the light rays into focus on the retina. As the eye ages, the lens becomes more brittle and less flexible. As such, the distance to which we can bring objects in and still keep them in focus drops off as the lens becomes more and more brittle and less and less able to change its shape with increasing age. Reading spectacles focus the light at the retina and make the image sharp again.
|
