Since 1999 the maximum term a licence can be issued for is 10 years. Up until the age of 75 vision is screened at the driver licensing agent when applying for renewal. If the applicant fails the screening they are required to have a further vision assessment at their optometrist. Vision screening machines are designed to detect as many drivers with insufficient vision as possible, in doing so some drivers fail the screening test but will latter pass at the optometrist or GP’s.
Drivers 75 or older can only renew licences for between 2 and 5 years and also require a medical certificate from their GP.
The standard of vision required to drive is complex and varies with the type of vehicle being driven, with higher standards required for trucks, buses and dangerous goods vehicles. Vision standards include minimum requirements for single vision, monocular and binocular acuity, fields of vision and night vision. All drivers require a minimum horizontal binocular field of vision of 140 degrees and no significant pathological field defect within 20 degrees of straight ahead.
For car and motorbike licence classes 1 and 6 (includes endorsements D, F, R, T or W) a minimum binocular acuity of 6/12 is required. For truck classes 2,3,4 and 5 (includes endorsements P, V,I or O)the requirement is 6/9. If this standard is only reached with the use of correcting lenses, then this condition will be recorded on the licence.
If acuity in the worse eye is between 6/18 and 6/60, correcting lenses should be used if a substantial improvement in acuity can be achieved. For these drivers applying for class 1 or 6 no general restrictions apply. For classes 2,3,4 and 5 the applicant would not meet the required standard and would need to apply to the NZ Transport Agency for exemption.
Drivers are regarded as monocular when they have only one eye or acuity in the worse eye is less than 6/60. As long as acuity reaches 6/12 in the best eye the driver passes classes 1 and 6 standards. Class 2, 3, 4 and 5 drivers will again fail to meet the standard or will need to apply for exemption.
The condition of “external mirrors fitted on both sides” is generally applied to licences where corrected acuity in the worst eye is less than 6/18. For these drivers a thorough eye examination is generally recommended.
This is a simplified outline of visual requirements for driving and more details are available by calling us or at www.nzta.govt.nz
We use our eyes on a daily basis without realising it, so whats actually happening inside our eyes that enable us to see?
Let’s follow the path of light as it moves through the eye. Firstly light enters our eyes through the cornea. The cornea is a clear and spherical structure that sits in front of the iris, the coloured part of your eye, and is the major focusing structure of the eye. Vitally important to the cornea is the tear film which protects, nourishes and provides an optically smooth surface for the cornea to function properly. Without a functioning tear film, the cornea becomes compromised.
Light then passes through a hole in the middle of the iris which we call the pupil. In everyday situations the amount of light varies significantly between places and time of day. The iris changes the size of the pupil (e.g. larger at night) to control the amount of light entering your eye, therefore the role of the iris is crucial in helping us see in all conditions.
The lens is the next structure light passes through on its way to the retina. The lens provides the eye’s adjustable focusing power enabling us to see at different distances. The brain sends signals to the lens in response to a blurry image on the retina within milliseconds, to make the lens change focus and clarify the image!
The retina contains over 150 million cells that send information to your brain. It is a complex light sensitive layer responsible for processing light into a message that the brain can interpret. The macula is the area on the retina responsible for detailed central vision.
All these structures work together to produce a final signal that is sent to the brain to help you perceive the world around you. These structures are very delicate! Even though a majority of people may not have any problems with their eyes, it is vital to be aware of and care for your eyes appropriately, especially when something does go wrong. You only have two eyes, and there have been no successful eye transplants as of today.
If you feel something is wrong with your vision, do not hesitate to see an optometrist. At Optik Eyecare we pride ourselves in clinical excellence. We are here to provide you with the highest quality eye care service available.
A 50 year old with normal vision is said to require about twice as much light as a child for comfortable reading, rising to about ten times more light for someone in their 80s or older.
Conditions that affect the retina at the back of the eye such as Macular Degeneration, the optic nerve such as Glaucoma or Parkinson’s disease, or clouding of the lens in the eye (cataract) will create changes in the amount of light required for efficient and comfortable vision and the amount of glare produced.
“As we move into the winter months, the days are not only shorter but the light is duller. Older people often struggle to see clearly particularly when trying to read poor quality print such as newsprint. Most people assume that daylight is sufficient, but it really isn’t and we have no ability to control the intensity or direction of daylight.” says Optometrist Naomi Meltzer. “People tend to think it is the size of the print which makes reading difficult, but often it is the lack of light and the poor contrast of the greyish print which does not stand out against the off-white or coloured background, which actually makes it difficult to read. This is particularly a problem to people who have some loss of vision due to Macular Degeneration or other age-related problems.”
Naomi Meltzer specialises in helping people with low vision, when changing their spectacle prescription no longer helps sufficiently. “So much of my work is teaching people to use a reading lamp correctly placed directly onto their reading or work bench to get better light onto the task to help them to see better. Lights in the ceiling, regardless of the type or wattage of the bulb, are not sufficient to help with reading either, because the light is so far away that by the time it falls on the book it is somewhat diluted and too weak for reading.”
She advises placing a light close to the task which then throws a strong light onto the task and makes it much easier to see. The light needs to be placed so that it does not reflect back into the eyes causing hot, dry tired eyes from glare, or cast shadows over the page. There are many magnifiers available which have the light built in as well as electronic magnifying aids which also convert grey print to bold black print to help people with low vision.
Naomi Meltzer is a low vision consultant. Her practice Magnifiers + More is located in Remuera. She is also available for low vision consultations once a month at Optik Eyecare, 20 Hall Street, Pukekohe. Independent optometrist John Kelsey is pleased to offer this service in the range of specialist optometric services provided by Optik Eyecare.
Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method ophthalmologists and optometrists use to determine the IOP and this is usually recorded in millimeters of mercury (mm Hg). It is normally measured as part of a comprehensive examination for all adults.
IOP is an important component in the evaluation of patients at risk from glaucoma and in determining the effect of treatments used in patients with glaucoma. Increased IOP above a normal range increases the risk of glaucoma but some patients can have high IOP levels without having damage to their optic nerves and fields of vision. These patients are called ocular hypertensive. Equally some patients can be diagnosed with glaucoma even with IOP in normal ranges, these patients have what is called low tension glaucoma.
The IOP is created from the balance between the rate of fluid production inside the eye and the rate at which this fluid drains from the eye. This balance can be affected by many factors including medications particularly steroids, genetic factors and by trauma to the eye. IOP varies throughout the day and night but is most commonly in the range of 10 and 20 mm Hg. IOP can also vary between a persons two eyes.
There are a number of different types of tonometers used to measure IOP. The reliability of all measures can be influenced by many factors including poor tear film quality, corneal thickness and scarring and previous laser refractive surgery. The most commonly used types are-
-applanation tonometry measures the force required to flatten a fixed area of the cornea. The higher the IOP the greater the force required. As the probe touches the eye anesthetic drops are required.
-air puff tonometry involves measuring the force required to flatten a certain area of the central cornea using a rapid pulse of air. This does not require any anesthetic drops but many patients find the puff of air disconcerting
-rebound tonometry involves a small light weight probe that makes momentary contact with the cornea. Soft wear within the instrument measures how the motion of the probe is altered by the cornea. As the touch of the probe is very gentle no anaesthesia is required and patients find this new instrument much preferable to the air puff tonometer. Due to these factors we now use this method as our first choice for routine IOP screening.
Do you struggle to see your computer screen with your current glasses? Are you forever peering over your glasses when you are reading and talking to people at the same time?
If so then a pair of occupational progressive glasses could be the solution to your problem.
Although normal progressive glasses are great for every day vision, allowing you to drive, walk around and still do some reading, they are not the best lens option for doing large amounts of desk and omputer work.
Likewise reading glasses are not always the best option for intermediate vision. People who try to do computer work wearing their reading glasses often complain of having to get very close to the screen, leading to poor posture and back problems.
Occupational progressive lenses offer a solution with improved intermediate and near zones, and can reduce the potential for headaches and visual fatigue with concentrated work.
This is particularly important for people who use multiple screens or are on a VDU screen all day in administrative or customer service environments. Occupational progressive lenses give a much wider intermediate zone set higher in the lens, allowing a more natural head position than in normal progressive lenses.
These lenses are ideal for computer work, reading, cooking, reading music, offering an extended range of clear near and intermediate vision. They are also useful at restaurants and in dimly lit areas so you can read the menu whilst talking across the table.
We can also make prescription safety glasses with occupational lenses, making them perfect for the workshop as well!
Some of the modern occupational glasses not only give you good near and intermediate vision, but also allow for comfortable mid distance vision across the office. This makes them useful for meetings and presentations, as well as walking around in your home, office or at the shopping centre. Often people use occupational progressives at work then switch to full progressives for driving and general outside use.
There are many types of occupational lenses available, each suited to particular visual requirements. These can be individually adjusted to match the patient’s prescription and visual needs. The staff at Optik Eyecare are able to recommend to you the best lens options for your requirements, and help you to choose a frame that will suit your prescription and your style.
In New Zealand we have the benefit of having relatively easy access to a high standard of eye care from optometrists and ophthalmologists in both the public and private sector. But in many poorer countries around the world including many of the Pacific Islands, the availability of eye care is very restricted. Generally eye examinations and any eye surgery is only available in the larger population centers, and then only to a limited degree. Complex eye surgery including retinal and glaucoma surgery is often not available at all.
To help alleviate this need volunteer teams of New Zealand ophthalmologists, optometrists and eye care workers regularly go up to the Pacific Islands, often travelling to remote areas. They screen large numbers of people providing spectacles and surgery for conditions such as cataracts and pterygium at no charge. The benefits to the individuals and the whole community are huge. With improved vision many children are able learn more easily at school and others are able to go back to work with their sight restored.
In cases of people requiring complex prescriptions, spectacles are made specifically for them in New Zealand. In most other cases the teams take up a large selection of recycled spectacles that have been donated by the public. Lions Clubs of New Zealand have for many years ran projects to reduce the levels of blindness and promote good sight in communities throughout the Pacific Islands.
As part of this commitment by Lions a project has been running for many years to collect and recycle used spectacles. Papakura Lions collects spectacles for recycling from throughout the North Island. In 1996 they purchased optical equipment allowing them sort out spectacles powers suitable for reuse. They also check for scratches and any frame damage then ultrasonically clean the spectacles ready to be packing. A team of volunteers from the club meets weekly to process the donated spectacles sent to then directly by the public and from optometrists.
To help this valuable Lions project we collect used spectacles and will process them ready to be transferred to Lions Papakura. Many people have old spectacles sitting around in draws at home, which are no longer of any use as spare pairs. This is a great chance to use these to help others get improved sight. So bring in your old spectacles to Optik Eyecare.
We are all aware these days how important it is to protect our skin from the sun and its damaging effects. Many people do not realize however that it is equally important to protect our eyes. Research shows that the sun’s ultra violet and infra-red rays contribute to eye diseases such as cataracts, pterygia and macula degeneration.
In the past providing sun protection to patients who wear glasses has posed a problem with many sunglasses being the wrong shape or curvature to fit optical lenses. Now those problems are over. With new lens milling technology we are now able to provide prescription sunglass lenses into almost any sunglass frames, including the wrap-around and blade sports frames. These include Bolle, Oakley and Adidas frames with the clip-in and out lenses, so popular with the cyclists, runners and golfers. Sports enthusiasts who require a prescription are no longer at a disadvantage, because most prescription lenses can now be fitted directly into these types of frames doing away with the prescription insert that clips in to the back of the frame, making it more convenient and with an increased field of vision.
There are also many options for the type of sun protection we can provide. Whether you are into fishing and water sports requiring a polarized lens, high contrast drive wear or a changing tint option there is a lens to suit every need. Specialized tints and coatings for the outdoors are very popular including mirror coatings for skiing, and high contrast tints and filters for shooting. The reduced weight and impact resistance of our modern lenses means prescription sunglasses are now safe for rigorous activity so your eyes can remain protected.
Some eye conditions make patients prone to being glare sensitive and in these circumstances protective sunglasses are a must. Just as some people get sunburnt more easily than others, some people are more sensitive to eye sun damage too. A regular eye health examination will enable the optometrist to assess your sun protection needs
With the improvement in lens designs now available, tinted progressive lenses are also an option for those who would like to read in the sun or sign the score card at golf! With so many options newly available please call in and talk to us about what sunglass options might be best for your needs.
A cataract is an opacity or cloudiness inside the natural lens of the eye. This cloudiness scatteres and reduces thelight passing through the eye, affecting vision. The most common cause of cataract is aging and UV exposure.
Common symptoms of cataracts include cloudy vision, increased glare, poor night vision and a rapid change of glasses prescription. When glasses can no longer provide adequate vision for driving or other important daily activities then cataract surgery is often necessary.
Cataract surgery is a very refined procedure where an Ophthalmologist removes the eye’s clouded natural lens and replaces it with an artificial, intraocular lens (IOL) implant. The new lens stays in the eye for the lifetime of the patient. The patient returns home immediately after the operation.
Cataract surgery techniques and intraocular lenses (IOLs) have evolved significantly over recent times. New technology provides better ways to correct vision after cataract surgery. People now have more choice in what type of IOL they may have fitted in their eye, depending on needs and lifestyle.
Types of IOLs include:
- Monofocal lenses (traditional IOL) which correct vision at a set distance but require the wearing of glasses for close-up tasks. In some cases one eye is set for far distance and the other eye for intermediate distances.
- Multifocal lenses correct vision at all ranges (near, intermediate and distance). These are a compromise lens and are used in a small number of patients.
- Toric lenses correct larger degrees of astigmatism.
- Lenses which have increase UV protection.
The most recent advances in IOL lens technology involves being able to customize the optical characteristics of implants to minimise any irregular optical distortions present in the patients eye. Additional surgical and laser procedures to reduce the amount of astigmatism in the cornea can also be carried out. These procedures can significantly enhance the quality of the vision achieved after cataract surgery, especially in low light levels .
Generally a month after the surgery patients return to their optometrist so that new glasses can be prescribed to correct any residual distance blur if needed, and to find the most appropriate correction for the patients near and intermediate requirements.
3D vision is important in helping you judge depth, distances and speeds.
Because your eyes are set a small distance apart, what your left eye sees, is slightly different to what your right eye sees.
Your brain combines these two images and looks for the differences between them. These very small differences are what make things seem 3 dimensional.
Film makers take advantage of this when they make 3D movies. If you look at a 3D movie without the special polarized glasses the picture is doubled up and unclear. When you put on your 3D glasses the image is separated into two different pictures, one for each eye. The slight differences between the images allow you to perceive depth instead of a flat screen.
People who only have one good eye cannot fully experience 3D movies and have more trouble judging depths than people with two good eyes.
The sudden onset of double vision whether constant or intermittent, large or small can be a serious sign that needs prompt evaluation. It generally causes disorientation and makes complex visual tasks like driving too dangerous. Most cases of double vision are not serious, but an eye exam as soon as possible to determine the cause is necessary.
There are many causes of double vision, which range from being minor and easily treated, to being associated with life threatening conditions. Fortunately most causes of double vision are easily treated.
It is initially important to determine whether the double vision is monocular (still present with one eye closed) or binocular (not present when one eye is closed) and whether it is of recent onset or long standing, intermittent or constant.
In the case of monocular double vision uncorrected astigmatism, cataracts or corneal irregularity are common causes. Quite often an update of spectacles will solve the problem. In some cases a referral to an ophthalmologist may be warranted, particularly in the case of cataracts.
The causes of binocular double vision are more varied. Common causes are associated with a reduction in the ability to keep the eyes aligned, particularly with age or recent illness. Some people have a tendency for their eyes to be misaligned and under normal circumstances our eyes can compensate for this, however this requires muscular effort and when the system becomes fatigued, the body is unable to cope and double vision occurs. We also see this occurring when a change in occupation causes increased visual demands leading increased fatigue of the visual system. In these cases glasses often will correct the double vision. Eye exercises by themselves or in tandem with glasses can also be helpful.
More serious causes that require urgent investigation include trauma, stroke, diabetes, tumours and thyroid disease. Assessment includes determining which eye is involved and whether the double vision is present in all directions of gaze or only some. This helps determine the causes of the double vision and if any other additional neurological or vascular assessments are required. Temporary relief from double vision canoften be achieved by patching one eye or using a stick on prism over a spectacle lens.
By far the majority of causes of double vision are benign, but a prompt assessment from an optometrist is important to determine the cause and organise any for referral at the appropriate urgency.