Presbyopia happens naturally in people as they age, usually from about 35 years onwards. The eye is no longer able to focus light directly onto the retina due to hardening of the natural lens. Ageing also effects muscle fibres around the lens making it harder for the eye to focus on up close objects. By the age of 55 most people have completely lost the ability for the eye to accommodate hence you need glasses to do any tasks close up such as reading, sewing and computers. When you are younger the lens of the eye is soft & flexible allowing tiny muscles inside the eye to easily reshape the lens to focus on close & distant objects. This is known as accommodation. A bit like a camera lens can focus on the background or the foreground depending how it is adjusted.
Symptoms of Presbyopia
Difficulty to read small print especially in poor light
Having to hold reading materials further away
Problems seeing objects close up
Individuals with a myopic (short sight minus prescription), find it easier to see close up without their spectacles or contact lenses.
Spectacles are the simplest & safest means of correcting presbyopia. These can be in the form of near vision spectacles, bifocals or varifocals. Alternatives are presbyopic contact lenses or eye surgery but these carry some risk and it is sensible to discuss these with your optician first. Presbyopia is corrected using a positive power lens. Individuals with plus power spectacles (hyperoperia or long sight) already will need additional plus power adding to their prescription. Individuals with a negative power spectacle prescription (myopia or short sight) will need a weaker prescription or may prefer to read without spectacles or contact lenses. The presbyopia part of the prescription is noted as an “Add” and is usually between +0.50 and +3.50 in power measured in diopters.