AT ARM'S LENGTH

As we get older, we find ourselves holding reading material further and further away. This is not because our arms are getting shorter! Rather, our eyes are losing their ability to focus up close, be it on reading a menu, threading a sewing needle, or tightening a small screw. This is one of the symptoms of presbyopia, the vision condition commonly associated with the aging process, and caused by the gradual loss of flexibility in the lens of the eye. Few people escape presbyopia, even if they have never had a vision problem requiring glasses before.

There are a number of treatment options for presbyopia, including glasses, contact lenses and surgery, and within these options there are various possibilities. Discuss these with your optometrist, who will guide you in terms of your specific needs.

CORRECTIVE LENSES

For those who need glasses for close work, but not for distance vision, the simplest solution is usually reading glasses, which can either be made up by your optometrist or even bought over the counter. Some people prefer to have bifocal (or progressive) reading glasses, with "plano" lenses (no prescription) in the top part of the lens and the reading prescription in the bottom, so that they're able to wear glasses full-time without having to constantly take them on and off.

If both distance and near vision need to be corrected, bifocal or progressive lenses would be the answer. Bifocal lenses have two points of focus, the main part being the prescription for distance vision, while the lower portion is for close work. While bifocal lenses correct only near and distance vision with a clear line between them, progressive lenses work for distance, intermediate and near ranges, with a continuous transition and no clear distinction between the different powers. Although vision is not necessarily better with progressive lenses, the uninterrupted transition from one distance to another is more natural, and they are cosmetically more attractive without the noticeable line. Without the image jump characteristic of bifocals, they are thought to be safer for driving. Some people think of progressive lenses as having three lenses in one, without the expense of three pairs of glasses or the nuisance of changing glasses for different vision needs.

It usually takes time to adjust to wearing bifocal and progressive lenses. During the adjustment period, wear the new glasses as often as possible, avoiding the temptation to go back to your old comfortable single vision glasses, as this can delay the process. Try to point your nose and chin at what you are looking at, whether it's a book, computer or traffic ahead. Lower your eyes rather than your head when reading. Peripheral vision may be distorted with progressive lenses, so turn your head when looking to the side. Allow up to two weeks to adjust, after which time any headaches, dizziness or other problems should be discussed with your optometrist.

CONTACT LENSES

Contact lenses can be a successful option for presbyopia. Like glasses, they are available in bifocal and multifocal alternatives, and are suitable for most prescriptions.

ALTERNATING VISION LENSES work similarly to bifocal glasses, where the top portion of the lens is used for distance viewing, and the lower third for close tasks. Most alternating vision lenses are rigid gas permeable lenses, and are slightly smaller than soft contact lenses. They float on the surface of the eye, resting just above the lower eyelid. When focusing on medium to long distances, the gaze remains level, and the middle to upper part of the lens is used. As the gaze drops for reading or other close activities, the lens remains stationary, and the view is through the lower portion of the lens. The lens can be made in a way that offers a clear, distinct line between the different powers, or there can be a gentle gradient between them that slowly transitions from one power to the other as the gaze drops.

MULTIFOCAL CONTACT LENSES or simultaneous vision lenses are made with different powers in one lens, targeting vision at varying distances, much like the progressive lenses for glasses. They are available in a wide range of styles and designs, with comfortable options for almost everybody. The different focal strengths are either arranged in concentric circles, from the centre of the eye outwards, or by a gentle gradient as the powers blend between near and distant vision.

Many people feel that multifocal contact lenses offer the best of both worlds - sharp clear vision without the need for glasses. However, as with most things, they do have disadvantages. Some people find it difficult adjusting both to wearing contact lenses and to the new vision experience. During the initial adjustment period and sometimes even longer, night time glare, shadows and starbursts poses a problem for some wearers.

MONOVISION is a variation on the standard use of contact lenses to help people with presbyopia. Even though most people have binocular vision, with the eyes working together, one eye is usually dominant over the other. With monovision, the dominant eye is fitted with a contact lens for distance vision, while the non-dominant eye is fitted with a lens for close work. The result is a compromise between distance and close-up vision. Overall, people who use monovision tend to adapt easily and see both distance and close-up items reasonably well, although some people find that their vision is not sharp enough for either. Generally, a certain amount of depth perception is lost, and some people experience difficulty with driving, particularly at night with the glare of oncoming headlights. A discussion with your optometrist will explore this as a choice for your lifestyle and vision needs.

SURGERY

The effects of monovision can be achieved with LASIK surgery, and is often the choice of people who prefer not to wear glasses or contact lenses. Using a laser, an ophthalmologist reshapes the cornea (the clear membrane in front of the eye) for distance vision in one eye and close vision in the other. The procedure is painless, healing takes place quickly, and improvement in vision is experienced almost immediately. Some people complain of compromised night vision after LASIK. It has been suggested that patients try monovision contact lenses before deciding on surgery, to ascertain that monovision is their best vision option.

No matter which option you choose, presbyopia does progress over time, and your contact lens or glasses prescription may increase to keep up with it. Regular eye examinations and consultations with your optometrist will ensure that your prescription is always up to date and providing you with the best vision possible.

DOUBLE VISION
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