Middle-aged people are plagued by reading difficulties named presbyopia. As mentioned in the previous passage, near blur is a normal age-related change and currently there is no way to stop it from coming.
Also reading or wearing glasses will not speed up or slow down the presbyopia process. So once we have presbyopia, what can we do to restore our reading vision? What are the differences between various presbyopia corrections such as reading glasses and progressive glasses? Is there any refractive surgery targeting reading difficulties? Now let us take a look.
Glasses are the easiest way to correct near vision. There are different types of glasses suitable for people with various vision needs. These glasses are mainly classified into single vision, bifocals and progressives.
1. Single vision glasses
Single vision reading glasses can correct vision at a single distance only. For example, a pair of single vision reading glasses allow you to read at 40cm but will not work for walking or watching television.
Even worse, if you have several near tasks with different working distances, such as needle work at 30cm, reading at 40cm and using computer at 50cm, you probably need few pairs of single vision reading glasses.
2. Bifocal Glasses
Bifocal lenses incorporate distant and near prescription into a single pair of glasses. Generally the majority portion of the bifocal lens is corrected for distant and there is a small segment at the bottom of the lens corrected for near vision.
It is more convenient than single vision lenses but the reading segment looks obvious and cosmetically does not look good. Also, the intermediate vision usually remains uncorrected when you wear bifocal glasses, such as the vision for computer, painting and reading musical notes.
3. Progressive Glasses
Progressive lenses are similar to bifocal lenses that the majority portion of the lens is corrected at far distance and a small reading area at the bottom. However, there is a corridor which progressively changes its power and allow a gradual transition from distant prescription to near prescription. Therefore besides far distance and near, it also corrects wearers’ intermediate distance vision.
Also, there is no obvious segment on progressive lenses which makes them cosmetically better than bifocal lenses. But progressive glasses require longer adaptation time than single vision and bifocal glasses. Despite that, according to the American Optometric Association, many people with presbyopia still prefer progressive glasses more than the other types of glasses due to the convenience. In addition, currently there are new generation of progressive lenses which have better lens designs to widen the wearers’ field of view and make it easier to adapt.
For contact lens wearers correcting presbyopia, they can correct one eye for distant prescription and one eye for near so that they can see both at the same time. But this will sacrifice their binocular vision especially when their presbyopia is more established.
They can also choose for multifocal contact lenses which can correct both distant and near vision for both eyes at the same time. Nevertheless, the visual outcome is limited by environmental light intensity and the majority of multifocal contact lenses do not correct astigmatisms.
Patients can also undergo refractive surgery such as LASIK to correct reading difficulties, and the correction will be similar to that of contact lenses — one eye for distant and near vision respectively. Another surgical approach will be leaving both eyes with low degree of shortsightness.
The near vision after surgery will be acceptable but the distant vision will be blurry which the patient may need glasses at far distance. On the other hand, unlike contact lenses, refractive surgery is an irreversible process. Patients also have to bear the surgery risks such as overcorrection, under-correction, induced astigmatism and regression. Patients are advised to try contact lenses to mimic the correction outcome before doing the surgery.
No matter which options you consider for your reading difficulties, it is still important to date your optometrist, at least once a year, for comprehensive eye examinations.
By Jeff Tang, Registered (Part I) Optometrist
Eyecare information by Swisscoat Vision Centre
Address : G/F Yuen Yick Building, 27-29 Wellington Street, Central, Hong Kong .
Appointment :+852 3579 4763
Website : www.swisscoat.com