Contact Lenses

ur Eye Test at Seventeen The Opticians of Esher in Surrey, United Kindom


1. Do I still need specs if I wear contact lenses?

Absolutely YES! The key to successful contact lens wear is to allow your eyes a rest without them, at least one day per week. This is why no contact lens wearer should be without a pair of spectacles. Furthermore, an average of 12 hours wear per day is recommended. There will always be times when you cannot wear contact lenses. Examples include: when you have Hay fever causing the eyes to itch; if you have a bad cold or flu; if you have a mild conjunctivitis; if you are taking a course of medication which is not compatible with lens wear or if you are about to take a trip in an aeroplane. Perhaps you simply need to see your way to the kitchen in the middle of the night in order to grab a glass of water. As a parent of a newborn infant, you will understand the demands placed upon you throughout the night – no time for contact lenses when your baby needs you. Your spectacles should also be updated so that the prescription matches that of your contact lenses. All too often contact lens wearers have spectacles that they cannot see with, as the prescription is so old. In order to overcome any dislike for your spectacles also ensure that you are aesthetically happy with the frames. Look good, see good and feel good!

2. Is it possible to get contact lenses for occasional use only?

Yes. Many spectacle wearers are happy using their glasses but want the option of contact lenses for certain occasions. Examples include partaking in a sporting activity once or twice per week or weekend or holiday use. At Seventeen The Opticians your optometrist will help you decide on the best contact lens system to meet your requirements. Generally, daily disposable soft lenses are the best type for occasional wear as they are so easy to use. The responsibility of cleaning them is removed since they are discarded immediately after use.

3. Is my prescription the same for both specs and contact lenses?

No. A contact lens prescription is only 100% complete when the details of their fit are included. This means that although the powers may seem similar to your spectacle prescription, the powers alone are not sufficient when specifying a contact lens prescription. Additional parameters like lens type, diameter and base curve must also be included.


Mr Smith’s Spectacle prescription is:

R) – 6.50

L) – 6.00/-0.25 x 180

However his contact lens prescription is:

R) 8.60/14.20/-6.00/F55

L) 8.90/14.20/-5.50/F55

Mrs Thompson’s Spectacle prescription is:

R) +4.50

L)+2.50/-1.00 x 90

Her contact lens prescription is:


L)8.70/14.40/+2.50/-0.75 x 90/Excel Toric

4. Can my contact lenses get ‘lost’ behind my eyeball?

No, this can NEVER happen as the eyeball has a ’safety net’ situated underneath both eyelids. This ’safety net’ is a membrane called the conjunctiva. The conjunctiva is a continuous membrane enveloping the outer portion of the eyeball as well.

5. Can I use any contact lens solutions or fluids for my lenses?

No. Always discuss your solutions with your optometrist if you are thinking of changing types. Whilst it is quite possible to change from one brand of multipurpose solution to another, it is not wise to change from a multipurpose solution to a peroxide type where neutralisation is required. Many contact lens wearers have made the mistake of using 3% hydrogen peroxide as a multipurpose solution.

6. How soon can I get contact lenses?

At Seventeen The Opticians our ample stock range allows us to fit and supply most established contact lens wearers in an hour. If you are new to contact lenses then more time is required in order to teach you how to insert, remove and take care of the contact lenses.

7. Is it okay to sleep with my contact lenses in?

Unless your optometrist has specifically said that you can, sleeping with your contact lenses in is a no-no. Our optometrists generally allow overnight wear only if you are using a silicone-hydrogel type of lens.

8. Is it okay to use saliva or tap water to clean or re-wet my contact lenses?

Absolutely not! Always carry a travel-size solution pack with you if you can. If you are not able to do this then pop a few strips of contact lens comfort drops or your contact lens container filled with fresh solution into your back pocket. Tap water and saliva are extremely unhygienic sources of fluid and many dangerous bugs can find their way to your corneas if they are used with your lenses. Don’t forget to wash your hands before handling your contact lenses.

9. What should I do if my contact lenses feel dry?

It is always wise to carry contact lens comfort drops in your handbag or back pocket. The preservative-free single use drops are best recommended and may be used as and when required for extra comfort. Environments to watch out for are smoky, dusty places, gyms, where working out causes your body temperature to rise and eyes to dry out as a result, air-conditioned and heated offices, especially when coupled with staring at a computer all day and long-distance driving. Take care to only use drops specified for use with contact lenses and ask your optometrist if you are unsure.

10. Can I wear contact lenses?

Yes – in most cases you will be able to use contact lenses. Certain individuals with unusual prescriptions or poor eye health may not be suitable. Ask

our optometrist to advise on the options available.

11. How long can I wear my contact lenses in a day?

You should never exceed an average of 12 hours of lens wear per day. If you require longer wearing times because of your lifestyle, speak to your optometrist about lenses that allow more oxygen to your eyes. Some individuals mistakenly believe that it is okay to wear one pair of lenses for some of the day and then change over to another pair for the rest of the day and so extend their wearing time. The suggested 12 hour wearing period is not specific to one pair of lenses. It means that in a day your eyes should never have more than 12 hours of lens wear irrespective of how many pairs you choose to wear!


1. How quickly can you make my glasses?

As our spectacles are made by a specialist lab, they can take on average a couple of days to make up. Lenses and frames that need to be custom ordered will take a little longer. Prescription sunglasses are made in about 3 days. Your specialist dispenser will be able to advise you on the length of the wait.

2. How thick will my spectacle lenses be?

This depends on your prescription, the type of lenses you choose, and your frame. The higher the prescription the thicker the lenses, but this can be minimised with high index lenses. Should you opt for plastic over glass lenses in a prescription over +/- 4.00 the thickness of the plastic will still be greater. In the lower prescription ranges, the type of lens does not matter as much. Ultra-thin 1.74 index plastics are now available which make plastic lenses much more feasible in more moderate prescriptions. As a general rule, the smaller the frame the thinner the edges of a lens for short-sighted individuals. Smaller frames always mean less lens, so significant weight advantages are gained when opting for something smaller. Ask your 20/20 dispenser about smaller diameter lenses. This means that the original lens size is smaller and the overall thickness is therefore less. Long-sighted individuals can have thickness reductions by asking to have their lenses “metzed” (Minimum Edge Thickness reduction).

3. What are the advantages of glass lenses over plastic lenses?

Plastic lenses are lighter and have 3 x the impact resistance of glass so are therefore more advantageous.

4. Does the price on the frame include the lenses?

No, the price on the frame relates only to the frame. Lens prices vary depending on the material and design of the lenses required. Ask your Seventeen The Opticians optometrist or dispenser to advise on the most suitable lens type for your prescription.

5. How difficult is it to adapt to varifocals?

The first time any spectacles are worn some adjustment time is required mainly because the new, clear vision needs to be accepted by your brain. Once it has learnt to recognise the images seen through the spectacles and become familiar with them, the initial “WOW” effect should have worn off. Varifocals are slightly trickier than single vision specs since they change in power as the eyes look from the top to the bottom of the lenses. Your eyes need to learn which parts of the lens to use when looking either close-up, far-away or in-between. Our optometrist can advise you on tricks to help you get started and in no time you should be well on your way to successful varifocal wear. A few individuals may struggle with varifocals simply because they cannot tolerate the changes in power which is inherent in the design of these. We advise that a period of 4 weeks be allowed before deciding that varifocals are not for you.

6. My new specs make me feel slightly odd even though my vision is clearer – why does this happen?

The brain is amazing when your vision was blurry before getting your specs, you may not have been 100% happy with it, but you were comfortable. Your brain adjusts to cope with any visual situation to the best of its ability. Suddenly when new spectacles are worn, the brain is ’surprised’ by this new, clearer way of seeing and it takes a few days to learn to recognise the new image. Certain individuals who are prone to vertigo, motion-sickness or are simply highly sensitive may take longer to adjust. Often you feel that the floor is either nearer or farther than before. This is because prescriptions produce changes in magnification and magnification is associated with the perception of distance. This means that even if the distance of the floor is the same, if it is seen as smaller, it will be understood to be further away. Likewise, something larger will be perceived to be closer. The best advice is to persist with your new spectacles and ‘wear them in’. If you are still feeling odd after 3 weeks of wear then please let us know. Steps to take in this instance are outlined below. See Something is definitely not right about my new specs what do I do?

7. I feel odd in my new spectacles even though they are made to the same prescription as my old ones – is this normal?

A change in your prescription is not all that causes a new pair of specs to feel weird. The frame change requires adaptation as you may be looking through a smaller or larger viewing area and the lenses may be closer or farther from your eyes compared with before. The lenses may also be tilted at a different angle in the new frame and perhaps the frame does not wrap your face as much or as little as it did previously. The type of lens design in the new specs will also influence your vision. For example, thinner, flatter, aspheric high index lenses often seem less clear when looking through the extreme periphery of the lens. Perhaps the centres of the lenses are higher or lower than before. This can also influence your initial comfort. Perseverance is the key to adaptation, but after 3 weeks without improvement, please see our specialist staff for further assistance.

8. Something is definitely not right about my new specs – what do I do?

Perhaps you are aware that your specs are not right even after trying them for 3 weeks. Before booking a retest with the optometrist, you should do the following:

Step One: Visit our specialist staff bringing in your new specs as well as any old specs if you feel that they seem better.

Step Two: Our staff will check your new spectacles to ensure that all the measurements required are correct and as per the optometrist’s specification. Any errors found will be rectified instantly, if this is possible.

Step Three: Assuming the measurements are correct, our staff will then recheck your frame adjustment to ensure that they fit your face in a visually optimal way.

Step Four: At this stage you may already feel better and simply need to readapt to the new fitting. If you still feel uncertain and suspect the prescription to be at fault, then you would be advised to see our optometrist for a reassessment. You will always see the same optometrist that consulted you initially, so an appointment may be required should that optometrist not be present on that day.

9. Do you stock children’s’ frames?

Yes. Ask about our Lafont & Loops designs. Remember to buy your child a frame that fits snugly, but has room for lengthening of its temples and is not too narrow widthways. This way the frame can be readjusted to match your child’s facial growth. If your child is less than a year old, it would be wiser to have the frames custom-made. This can be done through the hospital or privately, through optometrists specialising in paediatrics.

10. What are polarised lenses?

These are special tinted lenses that polarise light as it passes through. This means that light from only certain planes is allowed to pass through whilst the rest is eliminated. Visually, the effect would be to get rid of unwanted stray light. This can be quite useful for the avid fisherman, for example, who wants to see just beneath the surface of the water without having to worry about distracting reflections from the surface. They can be made with or without prescription, but may take slightly longer to put together as they need to be ordered. Ask our dispenser for more information on these lenses.


1. What is the difference between a squint and astigmatism?

A squint is when one eye is turned either up, down, in or out relative to the other eye. The term ‘lazy eye’ is sometimes used when the turn is not detected at an early age and left uncorrected. It is essential that any parents noting a turn in their child’s eye have them assessed by an optometrist or eye doctor as soon as possible. The sooner it is treated the better the prognosis for use of this eye in later years. By the time the child has reached 9 years of age, it may already be too late.

Squints are sometimes confused with Astigmatism. Astigmatism is a condition where the shape of the eye is like an egg, whilst a squint refers to a turn in the eye.


Often the eye is shaped like an egg or rugby ball. This is what we call astigmatism and it is quite a normal condition which most of us have to some degree. Like an egg, two main areas of curvature are found: one is flatter and the other is steeper. This causes the light to focus in two different positions such that the steeper or more curved area focuses further forward and the less curved or flatter further back. The effect on vision is to distort shapes so similarly shaped characters become confused. The letter G may be confused with a C and the number 2 may be mistaken for the letter Z.

Lenses have the ability to bend light or change its direction. A minus-powered lens causes light to diverge once it has passed through, whilst a plus-powered lens does the opposite by converging the light towards a point. A minus lens is generally thicker at the outside edges than at the centre and a plus lens is thicker at its centre than at the edge. This applies to both spectacle and contact lenses.

2. What are short-sightedness, long-sightedness and presbyopia?


Also known as Near-sight or Myopia, short-sighted individuals have trouble seeing things in the distance whilst anything close-up is clearer. This occurs because light from the objects being viewed focuses in front of the retina and not on it. It is believed that this mostly happens as a result of the eyeball being slightly too long. The scientific term for this is Axial Myopia.


Also known as Far-sight or Hyperopia, long-sighted individuals have difficulty with anything close-up whilst their general distance vision is not as bad. Light from objects viewed will theoretically focus behind the retina and not on it. However because the eye is able to naturally fatten the lens and cause light to bend more, this error in focus is overcome, which explains why distance vision is generally pretty good. When the same individual tries to look at something up close, much more effort is required, as light from a near object will fall much further back behind the retina. Vision at near is therefore worse.


As our eyes grow older the ability to focus clearly on anything close-up starts to diminish. This occurs because we lose our ability to accommodate or make the lens of the eye fatter in shape. One popular way of explaining how this happens likens the natural lens of the eye to a pillow with feathers inside. The lens contains many fibres (feathers) which grow throughout life in the same way that hair and skin continues to grow. This is not surprising considering that these tissues all come from the same founding cells. When the lens is younger and has fewer fibres it is more flexible and can change its shape more easily just as a pillow with fewer feathers can. When the lens is older and has many more fibres this flexibility is obviously lost which causes the near vision to blur.

Minus Lenses and Short-sight

As the short-sighted eye focuses light in front or short of the retina it makes sense to use a minus lens to take the focus back to the retina. It changes the direction of light before it enters the eye by making it more divergent. This, coupled with the normal focusing of the short-sighted eye, serves to place the focal point back on the retina assuming the correct strength of prescription has been used.

Plus Lenses and Long-sight

The long-sighted person’s focus is too far back so a plus-powered lens is ideal in order to create more bending of light. This convergence of light occurs in front of the eye and when the effect is coupled with that of the eye’s normal focusing the focal point is brought forwards onto the retina.

Plus Lenses and Presbyopia

The visual experience of presbyopia is the same as that for long-sight such that near objects are blurry. The difference is that long-sighted individuals have a prescription for their distance as well as near vision and that prescription is always plus-powered. Presbyopes have a more plus-powered prescription up close only, whilst their distance vision could be perfect, short-sighted or even astigmatic. So whatever the individuals distance prescription may be, the near prescription is invariably always different.

Toroidal Lenses and Astigmatism

The astigmatic eye possesses two main areas of curvature causing light to focus shorter along one curve and further back along the other. Since minus lenses push the focus of light further back and plus lenses bring focal points forwards, a combination of the characteristics of these lenses in a single lens would solve the problem of astigmatism. This lens form is termed toroidal and in contact lenses the term toric is often used.

3. Why do we become more “long-sighted” as we grow older?

This is due to a progressive change that occurs within the natural lens of the eye and is called presbyopia. Although similar to long-sightedness in its effect, these two conditions are not identical.

4. My close-up vision is not as good as it used to be – is this normal?

Yes – this change in your near vision focus happens to everyone and is called presbyopia. The effect of presbyopia is similar to that of longsightedness, but they are not the same.

5. I see black spots floating around in my vision especially when the sun is out – what are these and should I be worried?

These are called floaters. As the eye ages, more of these are seen and they are due to the changes in the vitreous jelly of the eye. The vitreous is simply a clear jelly that fills up the internal space of the eyeball between the lens and the retina. Changes may occur which cause the very fine fibrils contained in the jelly to clump together and become visible as floaters. As long as these are longstanding and not associated with any flashing lights, they are generally okay and all you would need to do is notify your optometrist and keep a watchful eye on them. If however you have not seen them before and they have only recently appeared, a thorough check with your optometrist or better still, an ophthalmologist (eye doctor), is advised. Floaters are most easily seen against a white or bright background. This is why they are more visible in the sunshine, against white walls or whilst flying and looking out at the clouds. Sometimes floaters are an indication of retinal tears and possible detachment of the retina. Although this does not happen all that often it is wiser to be safe rather than sorry so if in doubt, please find out!

6. Sometimes I see flashing lights, my vision goes’watery’ and I get a headache. Is this an eye problem?

No. You have probably experienced a migraine attack. Your GP would be the best person to advise you on what to do. Flashing lights that seem fairly constant are more serious as this may indicate a problem with your retina. Fairly urgent assessment of your eyes is then required and you should see an ophthalmologist (eye doctor) as soon as possible.

7. What is a cataract?

A cataract refers to any cloudiness within the natural lens of the eye. Most often, this is age-related, but accelerated risk of cataract is now caused by over-exposure to ultra-violet light. This is worsened by the fact that the Ozone Layer is constantly thinning. Our advice is to take care when in the sun and always don a hat and a good pair of UV-blocking sunglasses. Ask your optometrist for more information. If you develop or are developing a cataract, don’t worry unnecessarily. The sky does not fall down even though it might be slightly smeary to look at. A simple operation can be performed by an ophthalmologist (eye doctor) whereby the cataractous lens of the eye is removed and replaced by a new implant. You will probably be sent home the same day!

8. What is glaucoma?

There are two types of adult-onset glaucoma and both refer to an increased abnormal pressure within the eyeball. The rarer form is when an acute attack occurs. Symptoms include a painful, red eye and possible light sensitivity and nausea. The most common form of Glaucoma is the preventable chronic type. Sight is adversely affected if it is not picked up early, the long-term effect being progressively worsening tunnel vision. It is essential to have your eyes screened for glaucoma once you are over the age of 40 years as the relative risk increases from this point. Other factors increasing the risk of glaucoma are diabetes, high levels of short-sightedness, Afro-Caribbean descent, age and family history.

9. At the start of spring I can’t wear my contact lenses comfortably as my eyes itch – why is this?

You are probably suffering from an eye allergy. Spring often brings about more sneezing and increased pollen counts along with all the daffodils. Certain susceptible individuals will experience a reaction in the eyes and an allergic conjunctivitis results. The itching is usually confined to the upper and/or lower lids and possibly the corner of the eye closest to your nose. If you wear contact lenses, the best thing to do is switch to spectacles for the duration of the allergy and buy a small supply of daily disposable lenses so that you can use them for a few hours out in the evening if you are desperate. Daily disposables would be the best lens type if your allergies are fairly chronic and you refuse to wear glasses. For relief from the itching certain anti-histamine containing drops can be bought from your local pharmacy. Most cannot be used in conjunction with contact lenses. Other types of drops can be used over a sustained period of time to strengthen the membranes of the cells that cause the symptoms of allergy. These drops have a longer-term effect and are called mast-cell stabilisers. The active ingredient is usually sodium cromoglycate. Ask your optometrist or pharmacist for more information.

10. Why is it more difficult for me to see at night?

When it gets dark, our pupils dilate and this makes everyone more short-sighted. This is usually why night-time vision is worse than during the day even if you are wearing your up-to-date prescription. Should you be driving at night, more care should be taken on the roads, as oncoming headlamp glare can be quite distracting. Any prescription found for general use should obviously be worn in these conditions. Some inherited conditions of the eye like retinitis pigmentosa also cause problems with night vision. You would be advised to seek an ophthalmologist’s opinion if this is the case.