[Click! Health] "Presbyopia, Cataracts, Hyperopia... They Look Similar but Are Different"

Typically, when people reach their 40s or 50s, they begin to experience symptoms where distant objects are seen clearly, but nearby objects are not as sharp as before. This is because 'presbyopia' occurs in the eyes as aging progresses.

[Image provided by Pixabay]

According to Seoul National University Hospital, presbyopia naturally occurs as the human body ages. When light enters the eye through the cornea, the iris controls the amount of light, and the lens, which is convex-shaped, refracts the light and transmits it to the retina located at the innermost part of the eyeball. Among these, the lens becomes thinner when viewing distant objects and thicker when viewing close objects, adjusting the degree of light refraction.

However, as aging progresses, the contraction power of the ciliary zonules, which transform the lens into a convex shape, weakens, and the elasticity of the lens itself decreases. Consequently, the accommodative ability declines, and the lens does not thicken even when looking at close objects. This leads to presbyopia, which causes a decrease in near vision.

[Image courtesy of Seoul National University Hospital]

On the other hand, cataracts are diseases caused by problems with the lens itself. Cataracts cause the lens to become cloudy, preventing light entering the eye from passing properly through the cloudy lens. As a result, images do not form properly on the retina, causing symptoms of blurred and dim vision. Cataracts cause an overall decline in vision and are difficult to correct with glasses, whereas presbyopia only reduces near vision and can be corrected with glasses or contact lenses.

Hyperopia refers to a refractive error caused by the eyeball being too short or weakened refractive power. Like presbyopia, distant objects are seen clearly, but nearby objects are not. However, unlike presbyopia, hyperopia is not a condition that develops with age.

[Image courtesy of Seoul National University Hospital]

When presbyopia occurs, near vision is corrected by wearing multifocal glasses or magnifying glasses. For patients accustomed to contact lenses, presbyopia-specific contact lenses are sometimes recommended. If cataracts and presbyopia progress together, during cataract surgery, a 'multifocal intraocular lens for presbyopia' is implanted instead of the commonly used monofocal intraocular lens to treat presbyopia simultaneously.

Multifocal intraocular lenses can correct vision for both distant and near objects. However, compared to monofocal intraocular lenses, they cause more glare and halos, and distant vision may appear blurry. Therefore, multifocal intraocular lenses may not be suitable for professions that primarily involve night driving.

Additionally, surgeries that reshape the cornea or insert materials into the cornea are sometimes performed to treat presbyopia itself. However, if the lens function is significantly reduced due to presbyopia, the effectiveness of corneal refractive surgery may decrease, and complications such as corneal deposits may rarely occur, so caution is necessary.

Since presbyopia comes with bodily aging, efforts to slow down the overall aging process of the body are needed. The main cause of aging is oxidative stress, and to reduce it, one should mainly consume grains, beans, vegetables, and fruits while avoiding fats, meat, and alcohol. It is also important to avoid overeating and to maintain appropriate calorie intake along with moderate exercise.

Professor Kim Mi-geum of the Department of Ophthalmology at Seoul National University Hospital advised, "Living joyfully reduces stress, which can positively affect slowing down the aging process. Although presbyopia cannot be completely cured, it is a condition that can be treated enough to avoid significant inconvenience in daily life, so do not worry too much and consult an ophthalmologist."