Blurred Vision

Most cases of blurred vision can be corrected with spectacles, but if you are experiencing vision changes it is important to have your eyes comprehensively examined by an Optometrist to exclude other causes such as Glaucoma, Cataract, Macular Degeneration, Retinal Complications, etc. Most of these problems appear without one noticing and can only be detected by an eye care practitioner.


Spectacles are used to correct :

  • Myopia: short sightedness which causes blurred distance vision
  • Hyperopia: far sightedness which causes blurred near vision
  • Astigmatism: astigmatism which causes distorted vision when viewing detail at distance or near
  • Presbyopia: presbyopia usually presents at age 40 – 50 and causes blurred near vision
  • Computer Vision Syndrome: causes headaches, eye discomfort, or blurred vision & often occurs in users of lap-tops, PC’s, and tablets.



A cataract is caused by a loss of clarity of the Crystalline Lens, the focussing lens of the eye – located behind the Iris. There is no discomfort, but one will sometimes experience blurred vision or haloes around bright light sources. Advanced cataracts completely disrupt the path of light into the eye and severely affect vision.

Cataracts occur mostly due to advancing age, and are usually treated using key-hole surgery . The surgeon will make a 2mm incision ( sometimes using a laser), and insert a thin probe which vibrates at a very high frequency causing emulsification ( solid into liquid ) of the Crystalline Lens.This fluid is then vacuumed from the eye and a replacement lens is rolled into a sausage and injected into the eye, resting in the envelope created by the old lens capsule or outer layer.

These implants normally last for the lifetime of the patient, but regular 2-yearly checkups at your optometrist are advised.

The original lens was flexible and able to adjust focus by the action of the ciliary muscles of the eye. The implant is inflexible, and so great care is taken by the surgeon to calculate the best possible lens power. This will allow the patient as much visual freedom as possible, taking distance and near vision into account. Spectacles will still be required for certain activities.

It normally takes about 2-3 weeks for the eye to settle post-operatively ( although most patients are able to resume normal activities within a day or 2 ); and then the eyes are re-evaluated by the Optometrist to determine the new spectacle prescription



Colour Vision Abnormalities

Your Optometrist will test your functional vision and will determine whether you have a colour vision abnormality, as well as the degree or depth of the defect. The most common form of this problem is red/green; whilst blue/yellow colour vision defects are uncommon.


The degree of the defect is important as a high degree causes confusion between red & green colours which can be very dangerous for certain situations.


Click here for a list of some occupations which are affected by colour vision defects;



Diabetes is a condition which damages the blood vessels of the body, causing complications in the surrounding tissue.Your eye has very small blood vessels at the retina which can be easily viewed with an ophthalmoscope by looking through the pupil. Early retinal changes can be seen as small areas of blood leakage onto the retina, which if untreated will result in vision loss.

Your eye examination will include this procedure, and a retinal photograph will be taken ( see included images showing a healthy retina & an eye with diabetic retinopathy ). If any visible or functional changes are detected the eye can be treated in various ways such as with LASER Photocoagulation.

These changes in the eyes often occur before other diabetic changes in the body, and so this checkup can act as an early-warning system for your general diabetic health. If you are diabetic we suggest regular visits to your eye care practitioner, who will calculate how frequently you require checkups based on the risk factors such as type of diabetes, duration of diabetes, blood glucose and dietary control, smoking & alcohol, age, and whether you have family with diabetic retinopathy.

On your appointment day it’s very important that your blood sugar is normal. Abnormal sugar values can cause errors detecting your prescription; so you will need to re-schedule you appointment if your glucometer measurement is abnormal.


Double Vision

Double vision usually occurs when the eyes do not ‘work as a team’. If you think you have this problem, then a helpful way to check is to cover one eye when you are experiencing double vision. If the ‘double picture’ goes away then the diagnosis is confirmed.

Some causes of Double Vision are:

  • muscle imbalance ( where the extra-ocular muscles of the eyes over or under-act causing misalignment )
  • uncorrected refractive error ( where uncorrected myopia or hyperopia causes a misalignment of the eyes )
  • eye strain
  • trauma ( an eye injury or stroke can affect binocular function )
  • intra-orbital or intracranial tumour ( where a growth behind the eye causes misalignment, or a brain tumor causes loss of function ).


We advise a prompt eye examination if you are experiencing any form of double vision.

Dry Eye

Mild Dry Eye will only affect the eye occasionally; whereas severe Dry Eye can cause damage to the cornea affecting vision permanently, and any symptoms should be mentioned to your Optometrist or Ophthalmologist promptly.
Dry Eye often causes the eye to look slightly red & sometimes causes a sensation of grittiness. One may find that the vision tends to fluctuate, sometimes improving on blinking. Contact lens wearers will find that lens comfort and vision quality decreases after several hours of wear.

Computer Users are very prone to tear dysfunction; as is the dry environment caused by airconditioning, heaters, fans and in aeroplanes . Certain drugs such as anti-depressants, anti-histamines, decongestants, acne medications, anti-hypertensives and fat-burners can cause this dryness. Dry Eyes are common in those over 50, post-menopausal women, diabetics, and those who have has laser eye surgery (LASIK).
Treatment for Dry Eye includes eye drops in the day and eye gels on going to sleep & waking, lid massage therapy, warm compresses & lid scrubs to improve tear gland function, oral supplementation with omega 3 gel caps and lifestyle counselling.
Your Optometrist or Ophthalmologist will evaluate you and advise on which treatments will benefit your condition.


Effects Of Sun On The Eye

Ultraviolet Light is the dangerous portion or wavelength of sunlight which causes degenerative changes on the skin and the eye.
Frequent exposure to UV light may lead to the formation of pingueculas, pterygiums, cataract development, retinal degenerations, and lesions or growths on the soft skin around the eye that is often too sensitive for sunscreen application.
We advise the use of a good sunscreen, quality sunglasses, headwear, and avoiding sunshine between 11 00 and 3 00 wherever possible.
Special care should be taken with babies in ‘prams” when they are facing direct sunlight as their eyes have far less natural protection. Care should also be taken when children are involved in sport or outside activities at school – don’t trust that the teachers are all aware of the dangers; and sports or occupations that require looking up at the sky such as power line engineers, model aircraft & kite enthusiasts, sailors, and those who play cricket.
We stock special sunglasses for babies, toddlers & children; & our entire Sunglass Collection is guaranteed to screen all forms of UV A,B & C as well as infrared radiation without compromising on binocularity & sharp focus.


Eye Injuries

Any injury involving the eye can be a very traumatic experience and should best be attended to as soon as possible.

Sharp injuries from power tools or plants can easily penetrate the eye and hold a high risk of infection and further complications to the initial injury. Injuries of this kind should be treated as a medical emergency. Blunt trauma to the eye such as a golf ball or boxing glove strike may seem less serious by comparison, but can develop into retinal detachment or other complications long after the time of injury




Glaucoma is caused by irregular pressure in the eyeball, causing damage to the Optic Nerve at the back of the eye which results in vision loss. Normally there is no discomfort and most people are diagnosed with Glaucoma without being aware of any problem as the vision loss affects peripheral vision at first.

Although Glaucoma is so destructive, it is usually managed just by using medicated eye drops.

The way that we assess for Glaucoma is to measure the eye pressure, examine the Optic Nerve, measure the Optic Nerve thickness using a special laser-assisted tomography, and measuring the visual field of the eye to assess for vision defects.

Glaucoma assessment is part of our comprehensive eye examination routine at Allen & Dutton Optometrists and we encourage all to have routine checks; and we especially encourage those over 40 & those who have family with Glaucoma to plan regular checkups.




Asthenopia or eyestrain is one of the main triggers for Headaches, especially those originating in the area of the temples, eyebrows, or the lower area of the back of the head. It is very important not to ignore persistent headaches, and ipsilateral (one-sided) headaches should be checked urgently.

Unfortunately some headaches can be caused by systemic conditions such as high blood pressure, food intolerance,blood sugar fluctuations, brain tumors,etc. A comprehensive eye examination is recommended, which may detect a visual trigger amongst other possible causes of the headaches.



High Blood Pressure causes changes in the vascular system, and your Optometrist will examine the retina with an ophthalmoscope to detect changes in the small retinal blood vessels which may cause vision loss. An image of your retina called a Fundus Photograph is also used for the examination, and kept on record for future comparisons.

The small blood vessels of the Retina often show visible change before the condition manifests in other organs of the body, they can show changes before the condition manifests in other area’s of the body. An eye examination is thus an early warning system for vascular conditions such as hypertension.

Risk factors for hypertension are age, duration of the condition, degree of control with medication, family with hypertensive retinopathy, and lifestyle factors such as stress, diet, smoking & alcohol. Your eye care practitioner will use these factors to determine how frequently you will need to have your eyes examined.

Macular Degeneration

Macular Degeneration affects a significant portion of people over 60 years, causing changes in the area of the retina used for fine focus. This results in a gradual deterioration of central vision affecting reading, facial recognition, etc.
Age Related Macular Degeneration is detected by your Optometrist using an ophthalmoscope to examine the fundus at the back of the eye. The diagnosis can also be assisted with the use of new fundus cameras & scanning laser ophthalmoscopes which also help to monitor changes over time, as well as a simple test shown below called an amsler grid which can also be taken home by the patient to monitor changes.
Once detected, some forms of Macular Degeneration can be treated with special anti-angiogenic intra-ocular injections, laser treatment, photodynamic laser treatment, oral nutrient supplementation, and adjusting diet and lifestyle .Some risk factors for ARMD are age, a family history of the condition, and smoking.
It is interesting to note that until a few years ago there was no known treatment for Macular Degeneration.



Painful Red Eye

Injection or redness of the eye normally indicates that something is wrong, and can only be ignored if the redness clears after a few hours. Otherwise we advise that you visit your your Optometrist or Ophthalmologist soon, even when there is no discomfort.

Be sure to report any pain, especially if the ache is deep within the eye. Otherwise; try to determine if there is a mild scratchy or itchy sensation when blinking. Consider it urgent if you notice any blurred vision with a red eye.

Be aware of whether there is a mattery or watery discharge from the eye, or if you notice one or more pimples on the eyelash follicles. Note any swelling of the eyelid or eyeball, or drooping of the lids. Also look for any particles in the eye, ingrown eyelashes scratching the eyeball, or redness of the eyelid margins.

Contact lens wearers should discontinue wearing their lenses at the first sign of a red or uncomfortable eye.



A pterygium is a growth on the conjunctiva or ‘white part of the eye’ and usually starts as a small discolouration. The growth usually enlarges in size and thickness, forming a wedge shape with notable blood vessels.

A pterygium is caused by ultraviolet light, a component of normal sunlight. It is worsened by exposure to wind, water splashing, and is worsened by expo-sure to wind and water splashing on the eye, dry conditions, and rubbing the eye.

An Optometrist or Ophthalmologist will evaluate whether the Pterygium is growing into the cornea, the part of the eye used for vision, to decide whether surgery is nescessary. In most cases treatment with eye drops, quality sunglasses, and some counselling are effective.
Your eye care practitioner will usually photograph the lesion for future comparative analysis to assist with treatment and management.

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