Having trouble focusing on near objects, usually as we head into our 40s & 50s, you probably are developing presbyopia. It is a condition that affects everyone as they get older. Why presbyopia happens is not clear. When we are young we have a crystalline lens that is very flexible and the muscles within the eye can manipulate it so that it changes its shape, and therefore its power, so we can focus over a range of distances. This is a reflex and is done automatically without thought or effort. As we age, the lens becomes a stiffer, more rigid structure and it becomes harder for the muscles to get the lens to increase in thickness to become more powerful. As such, focusing up close becomes more problematic.
Globally, the prevalence of presbyopia continues to rise, in fact according to Jama Ophthalmology, about 1.04 billion people suffered from presbyopia globally in 2015 and this number was predicted by the National Eye Institute to rise to 1.37 billion in this year.
How does Presbyopia occur?
Presbyopia happens gradually. First, people start to put near objects a bit far, or increase the size of the font at the computer. It can work for few years but finally, the need for glasses to perform near activities appears. These glasses are magnifiers that can be used only for near in case the patient has good far vision, or may be added to the far glasses if the uncorrected far vision is not good. Presbyopia has been long time corrected with glasses but for those who don’t want to wear glasses, we have some surgical techniques available to correct this problem.
Treatment options for Presbyopia
Presbyopia surgery is not new. Monovision techniques are long time performed. They can be done either with laser or with intraocular lenses. The aim of monovision is to use the ability of the brain to process both eyes’ individual images to create the image we see. We call it binocularity. One eye is focused in far distance and the other eye is focused in near distance. Depending on the distance we focus, the brain chooses the best image as the principal image and uses the other eye as supporter of the main image. This combination is very useful in most of the daily activities and only in extreme far or small near activities, occasional use of glasses may be required. Monovision works quite well in myopic patients.
For those patients where monovision doesn’t match their expectations, we have multifocal intraocular lenses. These lenses are implanted after removing the natural lens. This is called refractive lens exchange. The multifocal intraocular lenses have different focuses to see in the most used near distances (mobile, books or computer screen) and also for far distances. They can be used in only one or both eyes, depending on the case. They can be implanted in cataract patients as well. Hypermetropic patients are most frequently implanted.
There are also some other techniques as corneal inlays, extended focus lenses or accommodative lenses. They may be used in some other cases but less frequently.
We select the technique depending on the age of the patient, the kind of glasses they are wearing, the current visual performance and the visual requirements. A complete eye check must be done to rule out any other pathology so the best results are obtained in healthy eyes. The results are excellent and most of the patients need no glasses at all. In few cases, it is possible some occasional use of glasses for specific activities. Even in these cases, we can provide high satisfaction levels to our patients and a change in their quality of life, where the continuous use of glasses before the surgery was very annoying for them.
*By Miguel Morcillo, Consultant Ophthalmologist, Specialist in Cataract, Cornea and Refractive surgery at Moorfields Eye Hospital Dubai