Answers to Common Questions
Click one of the following topics to jump to its entry on this page:
- Symptoms of Vision Problems
- Myopia (Short-sightedness)
- Hyperopia (Long-sightedness)
- Macular Degeneration
- Amblyopia (Lazy Eye)
- Eye Muscle Inco-ordinations
- Spots and Floaters
- Laser Surgery
- Colour Vision and Colour Blindness
- What is “Normal” in my vision?
- How Often Should I Have My Eyes Examined?
Symptoms of Vision Problems
Following is a partial list of symptoms in children and adults which indicate the need for a complete vision analysis:
- headaches, nausea or dizziness after visual concentration
- blurred or double vision at any time
- crossed or turned eyes
- blinking or eye rubbing after visual concentration
- dislike or avoidance of close work
- short attention span
- placing head close to book when reading or writing
- frowning while looking at the TV or blackboard
- difficulty reading small print
- difficulty adjusting focus between near and far objects.
Myopia is a condition in which near objects are seen more clearly than objects which are far away.
The main symptom is blurred distance vision. Short-sighted people often report difficulty distinguishing details on road signs and scoreboards.
Another common symptom is “squinting” the lids together in an attempt to see clearer. This works by narrowing the aperture they are looking through and therefore reducing the size of the blur circle on the retina inside the eye.
Myopia tends to first develop during adolescence as the eye grows to full adult size. Myopia occurs either due to hereditary factors or due to environmental stress and a subsequent spasm of the eye focussing muscles.
Myopia is corrected with either contact lenses or spectacles. Since these lenses are thickest at the edge, new spectacle lens technologies have been developed to produce thinner and lighter lenses.
For more information on Myopia, including an animated example of the condition, please click here.
Hyperopia causes a person to see clearer at far than at near.
Extra effort is required to try to clear the focus at all distances, resulting in eye strain and fatigue. This “strain” can manifest itself as headaches after close work, blurred near vision, tired eyes, difficulty adjusting focus from distance to near and near to distance, avoiding close work and short attention span for near tasks.
Common symptoms are associated with tasks which require continued visual concentration. It becomes a problem to maintain a clear focus on near objects; causing headaches and tired or aching eyes.
In some age groups a prescription for hyperopia often works to relieve the strain, rather than clearing the vision.
For more information on Hyperopia, including an animated example of the condition, please click here.
Astigmatism is an out-of-roundness of one or more surfaces in the eye’s optical system.
An eye with no astigmatism is spherical in shape, like a marble. On the other hand an eye with astigmatism has a distorted shape, slightly like a grape.
In lesser degrees this can cause strain and discomfort after visual concentration; while in higher degrees astigmatism causes images at all distances to be distorted or blurred.
For more information on Astigmatism, including an animated example of the condition, please click here.
Presbyopia is a gradual loss in the focussing ability (accommodation) of the eye and is part of the normal vision changes we all experience.
This is caused by a natural hardening of the eye lens, so that by the early 40’s it does not respond as well to the muscles intended to change the focus of the eye. As a result, people in this age group start to have difficulty with near tasks like reading small print, threading a needle, etc.. This is especially true at the end of the day when lighting levels are poorer and the individual is more likely to be tired. Correction consists of reading spectacles, bifocals or the newer progressive lenses.
For more information on Presbyopia, including an animated example of the condition, please click here.
Macular Degeneration (MD) is a disease associated with aging that gradually destroys central vision. Central vision occurs at the macula on the retina, at the back of the eye. Because it is the central part of vision, it is needed for seeing objects clearly and for common everyday tasks such as reading and driving.
In some cases, MD advances so slowly that people fail to notice the gradual deterioration of their vision. In others, the disease progresses faster and may lead to a permanent loss of central vision.
While there is presently no cure for Macular Degeneration, there are steps that you can take to prevent or slow the progress of the disease.
MD is present in 15% of people between the ages of 70-75 and is now the leading cause of blindness and severe vision loss in Australia.
For more information on Macular Degeneration, including an animated example of the condition, please click here.
Amblyopia (Lazy Eye)
Amblyopia is a reduced vision, generally in only one eye. The condition usually results from poor eye co-ordination, from having a turned eye, or after having one eye which requires a far greater lens power.
The reduced vision occurs because, for one or more of the above reasons, one eye is being used less than the other. When detected early enough, patching, vision training and lenses may help to reverse or prevent permanent damage to the vision.
For more information on Amblyopia, including an animated example of the condition, please click here.
Eye Muscle Inco-ordinations
Eye muscle inco-ordinations occur when the eyes do not align or focus together as a team. This improper control of the eye muscles can result in crossed-eyes, poor focussing ability, or simply discomfort and headache from the extra effort required.
Common remedies are vision training, prisms, therapeutic spectacles, bifocal or progressive lenses.
For more information on phorias, including an animated example of the condition, please click here.
Glaucoma is a disease where the pressure within the eye is typically increased (although not always). This can damage parts of the eye, and if left untreated may result in blindness.
Many times the symptoms are not noticeable until damage to the eye has already occurred. Diagnosis consists of having regular eye examinations which include a pressure measurement (usually every 2 years for patients over 40), to enable early detection of possible problems.
For more information on Glaucoma, including an animated example of the condition, please click here.
Cataract is an opacity or clouding of the lens inside the eye, then distorting the light as it enters. Cataract is often confused with pterygium but cataract cannot be seen on the surface of the eye.
Symptoms of cataract may include a gradual painless decrease in clear vision, hazy vision, increased sensitivity to glare, and even double vision.
Special tints or filters can often improve vision and UV protection can help to slow development of this condition.
The eventual “cure” is surgical removal of the lens with cataract and replacement with an artificial lens (intra-ocular lens implant).
For more information on Cataract, including an animated example of the condition, please click here.
Pterygium is a triangular growth of degenerative tissue on the white of the eye (sclera), usually on the nasal side, that may extend onto the clear window of the eye called the cornea.
A pterygium results from irritation due to long term exposure to ultra-violet light (UV), wind, glare or dust. Treatment is by eliminating the irritation with protective eyewear, eye-drops or surgery.
Spots & Floaters
Spots and floaters are semi-transparent specks of natural materials inside the eye, which sometimes can be seen floating in the field of vision.
Some patients comment that they look like cobwebs or threads, and most usually notice floaters when looking at a bright clear background like a ceiling or plain coloured wall.
They can be caused by debris left over from before birth, injury or eye disease. A full eye examination will determine the cause and whether any follow-up is needed.
Refractive surgery describes a group of procedures where surgery is used to correct the focus of vision rather than spectacles or contact lenses.
The most modern techniques use computer controlled lasers to remove a layer of the cornea (window at the front of the eye) and to reshape it to correct vision. Our practice is involved in the assessment of suitable candidates, referral of patients for this procedure, and follow up after the surgery.
Refractive surgery is best suited for patients who wear spectacles or contact lenses all the time. Most patients do not need spectacles for general wear after the surgery but it is likely that a prescription will often be needed for fine work or as focussing problems (presbyopia) develop naturally in the 40’s.
Originally, laser surgery could only correct short-sightedness. Now it offers hope to those suffering astigmatism (distorted vision) and long-sightedness. Laser surgery gives speedy results with minimal pain. But this procedure is not suitable for everyone. If you are under 18 years old, pregnant, or have had changes to your prescribed corrective lenses in the past year, we usually do not recommend laser surgery.
Cost is an important factor: laser surgery costs up to $2000 per eye and is not covered by Medicare or any other private health fund (though in some cases it is partially tax deductible). Most laser clinics offer finance plans or interest-free terms.
While laser techniques in refractive eye surgery have been years in the making, only in this decade has laser surgery become truly widespread. It is estimated that up to one and a half million people worldwide had such operations, many thousands of those in Australia.
Reputable eye surgeons emphasise that not all laser patients will attain 20/ vision. This depends on various factors, including the severity of the patient’ original vision problem. Some patients may still require glasses or after laser surgery.
Those with presbyopia or “ageing eye” which often occurs in one’s early 40’cannot generally be treated by laser surgery, although in some laser treatment may be used for one eye only.
Colour Vision and Colour Blindness
A routine part of our eye examinations is an assessment of colour vision, especially for children.
Colour blindness is almost always inherited, although it can be acquired condition as a result of some diseases or injuries.
The abnormality is sex linked, recessive, and carried on the X chromosomes. This means that males need only have their one X chromosome affected to be colour blind while females must carry the condition on both their X chromosomes to be colour blind. If females have it only on one X chromosome they will carry the condition but still have normal colour vision themselves.
As a result, about 8% of males and 0.5% of females have colour vision deficiencies. Almost all colour deficient people do see most colours but they will have difficulty identifying particular ones, confusing certain shades of red and green for example.
As children, few of these people will be aware that they have a colour vision deficiency but the detection of these problems is important, especially when career choices are affected.
For more information on Colour Blindness, including an animated example of the condition, please click here.
What is “Normal” for my vision?
It is normal for most eyes to be 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 a relatively stable time 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 the lens inside the eye. The result is a totally normal and expected change called “presbyopia”, which continues into the 60’s.
After 60, the eye will tend toward less long-sightedness or more short-sightedness as the inner part of the eye lens hardens. Sensitive vision drops and the retina’s fine discrimination of colours is dulled. By 70 most eyes show signs of cataract and the older, harder, clouded eye lens scatters light so that glare often becomes more of a problem.
How often should I have my eyes checked?
Your optometrist will advise you of the interval between your full eye & vision examinations which is appropriate for your vision and eye health needs. This time interval does vary for different situations, so we contact our patients when their next routine check is due. Changes in vision and eye health are often quite slow and subtle, and can easily go unnoticed if not checked regularly.
Of course if a problem arises sooner, please make an appointment so that we can assess the situation for you.