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Frequently Asked Questions • General• Contact Lenses • Spectacles • Sunglasses • Sight Conditions |
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GENERAL 1. How often should I have an eye exam? At 20-20, we recommend that you have a full Eye Examination once every 2 years, but this may vary depending upon the nature of your prescription. Since the Section 60 Optician's Act 1989, was revised in 2005, contact lenses cannot be supplied until a full contact lens consultation has been conducted every year. This is why we recommend that contact lens wearers should have a full Eye Examination once every 12 months. Some contact lens types may require more frequent assessments and these recommended intervals assume that you are not experiencing any symptoms of visual change. 2. Will my sight become worse if I start wearing spectacles or contact lenses? Wearing a prescription does not make your vision worse. Often when someone wears spectacles for the first time, the visual improvement is so amazing that vision without them seems much worse. This is because the brain can now compare two images directly: one with spectacles and one without. Prior to this the brain had nothing to compare and therefore the vision did not seem quite so fuzzy, when in fact it was. Both nature (your genes) and nurture (life's influence on you) decide the way your eyes will change with time. 3. How long will the Eye Exam take? The Eye Exam should not take longer than 20 minutes, assuming no extra tests or contact lens fittings are required. We endeavor to have completed our service to you within an hour. Our comprehensive pre-testing service includes an Optomap photo and pressure testing, so our customers should allow 10 minutes for these tests to take place before seeing their optometrist. 4. What does the 20-20 Eye Exam involve? Refer to Eye Exams for detailed information. 5. What is the Optomap? Refer to Optomap Retinal Scan for detailed information. 6. Am I entitled to a free NHS Sight Test and NHS Vouchers? Your eligibility is subject to certain conditions. Please see our NHS section for more information. 7. What are your opening hours? Refer to Opening/Closing Hours, since these are subject to change throughout each season. 8. How do I get there? Closest Tube: Goodge Street Station Tube Line: Northern Click here for Street Map 9. What is the difference between 20/20 Vision and 6/6 vision? There is no difference! Both of these fractions denote perfect sight. 20/20 Vision is the imperial version measured in feet, whereas 6/6 is the metric equivalent in meters. For more information on perfect sight click on Eye Conditions. 10. What is the difference between an ophthalmologist and an optometrist? Ophthalmologists are sometimes known as eye surgeons or eye specialists as they concentrate on diagnosing and treating eye diseases. They are essentially medical doctors that specialize in eyes and may perform surgery and prescribe medication as they see fit. Optometrists will screen for eye and associated diseases, and refer to ophthalmologists if necessary. However, they concentrate on spectacle and contact lens prescriptions. Some specialize in eye exercises to improve eye muscle conditions, pediatrics, sports vision or low vision where help may be given in the form of telescopes and magnifiers. 11. What is LASIK surgery? LASIK stands for Laser In Situ Keratomileusis. It is a form of refractive surgery, which corrects short or long-sightedness and astigmatism. It cannot correct presbyopia, but treatment is sometimes aimed at leaving one eye slightly short-sighted in order to account for this condition. For more information on presbyopia, see Eye Conditions. LASIK can only be performed by an eye surgeon. A microsurgical instrument is used to create a flap through the cornea (front part of the eye). Once the flap is moved out of the way, the exposed tissue is reshaped using a laser. This reshaping is what corrects the vision. The flap is then replaced over the cornea and the eye is allowed to heal. To find out if you are suitable for LASIK you would need to attend a pre-operative assessment at which your corneal thickness will be measured and your prescription verified for stability. If your cornea is too thin or your prescription is still changing, you will probably be advised against LASIK. Pre-operative assessments are offered by all the leading companies involved in laser eye surgery. 20-20 is happy to inform you that we are associated with LASIK surgery provider, ULTRALASE.  CONTACT LENSES 1. Do I still need spectacles if I wear contact lenses? Absolutely! 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 of spectacle 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 medication that is not compatible with lens wear. • If you are about to take a trip in an airplane. 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. Generally, daily disposable soft lenses are the best type for occasional wear. The responsibility of cleaning them is removed since they are discarded immediately after use. 3. Is my prescription the same for both spectacles 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. 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. It is not wise to change from a multipurpose solution to a peroxide type where neutralization 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 20-20 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. Our patient contact lens fitters will spend as much time as you need in order to make sure you are comfortable, so don't feel pressured and take your time as you are introduced to the new world of 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 not safe or healthy for your eyes. 20-20 optometrists generally allow overnight wear only if you are using a silicone-hydrogel type of lens. For more information, see Overnight Wear. 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 it is strongly suggested to pop a few strips of contact lens comfort drops or fill your contact lens container with fresh solution into your back pocket. Tap water and saliva are extremely unhygienic sources of fluid and dangerous bugs can find their way to your corneas if these forms of solutions 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 with you at all times. The preservative-free single use drops are best recommended and may be used when required for extra comfort. Take care to only use drops specified for use with contact lenses and ask your optometrist if you are unsure. 10. 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, which extends 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 no matter how many pairs you choose to wear! 11. What types of colors does 20-20 offer for color contacts? 20-20 offers a wide range of different colours for those that would like a change from their natural eye colour. Not to mention that 20-20 also has a variety of novelty contact lenses that can change the shape of the eye, for example, Novelty Contact Lenses for more information. SPECTACLES 1. How quickly can you make my glasses? As our spectacles are made on site, they only take an hour to make up. Sometimes this can be done in as little as 20 minutes as our cutting machines are extremely fast. Lenses and frames that need to be ordered will take a little longer. Prescription sunglasses are made in about 3 hours. Your 20-20 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 minimized with high index lenses. As a general rule the smaller the lens for short-sighted individuals. Smaller frames always mean fewer lenses, so significant weight advantages are gained when choosing 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). More information on lens thickness and frames can be found in the Spectacle Lenses section. 3. What are the advantages of glass lenses over plastic lenses? Plastic lenses are lighter and have 3 x the impact resistance of glass, whereas glass is thinner. See Glass vs. Plastic for more information. 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 20-20 optometrist or dispenser to advise you 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. The reason behind this is because the new, clear vision needs to be accepted by your brain. Varifocals are slightly trickier than single focal spectacles since they change in power as they 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 close-up, far away or in-between. 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 spectacles make me feel slightly odd even though my vision is clearer. Why does this happen? 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 recognize the new image. Certain individuals who are prone to vertigo, motion-sickness or are simply highly sensitive may take longer to adjust. You may 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. 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 contact us and we will help with your situation. 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 spectacles to feel strange and different. 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 spectacles 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 centers 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 contact our store for further assistance. 8. Something is definitely not right about my new spectacles. What do I do? If your eyes are still not becoming comfortable with your new spectacles after 3 weeks, please proceed with the following steps: Step One: Visit our sales team by bringing in your new spectacles as well as any old spectacles if you feel that they seem better. Step Two: Our team will check your new spectacles to ensure that all the measurements required are correct with the optometrist's specification. Any errors found will be rectified instantly, if this is possible. Step Three: Assuming the measurements are correct, our team 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 your 20-20 optometrist for a reassessment. It is generally better to see the same optometrist that consulted you initially. 9. Do you stock children's' frames? Yes. Ask about our Fisher Price and Barbie designs. Remember to buy your child a frame that fits snugly, but has room for lengthening of its temples and is not too narrow width wise. 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 Great Ormond Street Children's Hospital or privately, through optometrists specializing in pediatrics. 10. What are polarized lenses? These are special tinted lenses that only allow certain planes of light to pass through and the rest are eliminated. Visually, the effect would be to get rid of unwanted stray light. They can be made with or without prescription, but may take slightly longer to put together as they need to be ordered. Ask your 20-20 dispenser for more information on these lenses. SUNGLASSES 1. Is it really important to wear sunglasses? Yes, yes, yes! Having your eyes exposed to UV rays can be extremely damaging and increases the risk of developing macular degeneration and cataracts. This is because ultraviolet light can damage your eye's retina and cornea. Wearing sunglasses on sunny days also offers a benefit of improved vision at night. For optimum protection we recommend to wear sunglasses that are 100% UV absorbent. 2. Can I have my prescription in my sunglasses? Absolutely! Ask your optometrist on how you can have your prescription lenses made into sunglasses, because we know how important it is to make sure you are able to see and be protected when facing the sun. 3. How do I know which type of sunglasses will suit my face? With such a wide variety of designer glasses at 20-20, it helps to know what frame shape suits your face. The shape of your face can really impact on what types of frames would look best on you. Refer to Sunglasses to see a guide on all types of facial structures and the correct sunglasses to match them. SIGHT CONDITIONS 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 parent 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. Squints are sometimes confused with astigmatism. Astigmatism is a condition where the shape of the eye is like an egg, whereas a squint refers to a turn in the eye. See Sight Conditions for more information on astigmatism. 2. What are short-sightedness, long-sightedness and presbyopia? Please refer Eye Conditions for detailed information. 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 it is similar to long-sightedness in its effect, these two conditions are not identical. Please see long-sightedness and presbyopia for more information. 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 long-sightedness, but they are not the same. See Sight Conditions for more information. 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. 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 more easily seen against a white or bright background. This is why they are more visible in the sunshine, against white walls or while flying and looking out at the clouds. Sometimes floaters are an indication of retinal tears and possible detachment of the retina, and if this is the case it is better to be safe than sorry. Look into Emergencies for more information. 6. Sometimes I see flashing lights, my vision goes 'watery' and I get a headache. Is this an eye problem? No, you've 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. For more information on where to get help, see Emergencies. 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 can become worse by the fact that the Ozone Layer is constantly thinning. Our advice is to take care when in the sun and always wear a hat and a good pair of UV-blocking sunglasses. If you develop or are developing a cataract, don't worry. A simple operation can be performed by an ophthalmologist (eye doctor) whereby the cataract 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. If the sight is adversely affected and is not picked up early, the long-term effect could be a progressively worsening tunnel vision. It is essential to have your eyes screened for glaucoma once you are over 40 years of age 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 because my eyes itch. Why is this? You are probably suffering from an eye allergy. Spring often brings about more sneezing and increased pollen counts. 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 to 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. 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 allergies. These drops have a longer-term effect and are called mast-cell stabilizers. 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 (eye doctor) opinion if this is the case. |
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