The term Presbyopia refers to a medical condition that is caused from the eye aging causing poor ability to focus on closer objects. Because it is caused by aging, it only gets worse over time. There are some symptoms to look out for, including having a hard time reading smaller print, headaches or strained eyes, and change in how close you must hold reading material. Additionally, this condition varies between individuals and the level of clarity issues. Also, there could be multiple forms of refractive errors along with the presbyopia.
Unfortunately, this is a natural and expected result of the aging process which occurs because the lens begins to harden over time, preventing light from focusing behind the eye, instead of the retina while viewing objects up close. It falls under the category of refractive errors, including astigmatism, farsightedness and nearsightedness, requiring eye examinations to be diagnosed properly.
Generally, the treatment simply requires prescription eye glasses that provide the individual with the ability of increased focus to the lower section of their lens. In mild cases, individuals may find reading glasses over the shelf to be efficient enough to correct their vision.
Those who are age 35 or higher have a higher risk to develop presbyopia. However, as we age everyone eventually gets affected by this condition at some degree. The first documented mention of this medical condition dates back to 4th century BC, in the writing by Aristotle. However, the first glass lenses were not introduced as a treatment option until late in the 13th century.
Signs and Symptoms
Difficulties with reading is often the first thing people will begin to notice, especially within areas with lower lighting. Additionally, there can eyestrain during longer periods of reading, close objects appear blurred (temporarily or constantly) when the distance of view is changed. Those with more extreme cases have reported it feeling like their arms have become “too short” for holding things at a distance they can comfortably read at.
Similar to the other types of focal conditions, the sunlight can make the defect less noticed because the light reduces the pupil’s size. The reason this happen is, as the lens size gets smaller the focal ratio increases our perception of depth and results in a reduced number of blurred objects.
Furthermore, onset corrections depend on the individuals profession or if they have miotic pupils. For instance, homemakers and famers often wait until later in life to begin correction treatment. However, those in construction, service workers, or any profession heavily dependent on clear vision tend to seek correction much earlier.
Fun fact, it is possible for underwater photography divers to first notice their change in vision while being under the water, prior to noticing it within a regular routine above ground. This is because of the lack of light under water.
Those who suffer with nearsightedness commonly read without glasses just fine, even as they’ve aged. Although, the longer distance vision still produces difficulties, and never goes away. For those thinking of refractive surgery are suggested to doing so prior to age 40 to correct nearsightedness, as waiting can be more of a disadvantage as the risks of both eyes losing focus from presbyopia increases. At this point, glasses will be required for reading anyway. Meanwhile, myopes that have mild astigmatism often notice closer objects better with aging eyes, but higher levels of astigmatism encounter worse near vision without correction.
Monovision is one surgical method that can help correct this issue, sometimes referred to as “distance vision eye” or “reading eye” techniques.
The hardening of lenses lower crystallin levels, and increased temperatures are believed to raise the rate of hardening.
The ‘eye’s near point’ is a term referring to the closest objects come into focus. Standard NPD (near point distance) is 25cm, and commonly the distance used for optical instruments and devices. However, there’s confusion regarding the way focus mechanisms work. Some publications refer to the lens being suspended within a membrane called zonula. When the zonula’s tension gets released, it enables lenses to take a rounder shape.
The ciliary muscle provides this tension, and is believed to be circumferential with a contraction design similar to that of the sphincter, increasing and decreasing tension levels, enabling focus to change between near and far.
The eye transfers images into electrical signals received by the brain, then interpreted by the individual. Therefore, two key aspects must be overcome to avoid issues from presbyopia: the brains visual processing and the eye’s optical system.
This is by far the easiest and cheapest approach to correct your vision, but may only work for mild to moderate conditions. Using eye glasses or contact lenses can improve vision up to +4.0 diopters. Some options commonly used include bifocal or varifocal lenses for eliminating the necessity of spectacle style lenses.
A popular option, but can be more expensive than corrective lenses as they can easily be lost, torn, or dry out, and require being refilled periodically. However, multifocal contact lenses are able to correct an individual’s vision surfing from near and/or far sightedness. Monovision contact lens treatment is when patients use two different lens strengths to correct a different condition in each eye.
This should be the last option as eye surgery is usually a permanent reshaping of the eye. However, for those who no longer want to wear corrective lenses, there are new procedures available.
Laser blended vision is one procedure that can be conducted to correct a range of vision impairments. It uses lasers for correcting the distance difficulties within the eye.
Corneal inlay implants is a treatment where patients receive implants to reduce effects of distance issues.