Recently, 50-year-old Mr. Ye noticed his vision becoming blurry while reading the newspaper. When he put on his nearsighted glasses, distant objects appeared clear, but close-up objects remained hazy.A friend suggested he might be developing presbyopia, but Mr. Ye firmly dismissed the idea. He argued that as a myopic person, he wears concave lenses, while presbyopia requires convex lenses. Since the positive and negative powers cancel each other out, why would he still experience blurred vision?
Many people share Mr. Ye's belief that those with myopia cannot develop presbyopia in old age.Is this really the case? Furthermore, many seniors who develop presbyopia don't visit an optician to get glasses; instead, they buy a random pair on the street as long as they can see clearly. Is this approach correct? Our reporter interviewed Dr. Zhang Xianmei, an ophthalmologist at the Second Municipal Hospital, on this issue.
Presbyopia is an inevitable part of aging
Dr. Zhang explained that to understand whether myopic individuals develop presbyopia later in life, one must first grasp the nature of presbyopia. Using a camera's functionality as an analogy:
When taking a photo, a camera must adjust its lens focus to capture a clear image. The focal length needed for a 5-meter subject differs from that for a 1-meter subject, and this adjustment is performed by the photographer. The human eye operates on a similar imaging principle.
To see objects at varying distances clearly, the human eye must constantly adjust its focus. This adjustment is achieved by altering the curvature of the eye's lens."When young, the lens possesses excellent elasticity, enabling clear vision at various distances. With age, the lens gradually loses elasticity, and the muscles controlling eye movement also weaken. The range of lens adjustment shrinks, making it difficult to see nearby objects clearly," Dr. Zhang explained. This decline in the eye's natural focusing ability is a normal part of aging and degeneration, leading to the onset of presbyopia—a condition no one can avoid.
Myopic Individuals Also Develop Presbyopia
The saying "Presbyopia strikes at forty-eight" holds true for most people, with the condition typically emerging around age 48. Dr. Zhang addressed a common misconception that myopic individuals avoid presbyopia in old age, based on some myopes seemingly managing close-up tasks without reading glasses later in life. This view is actually incomplete.In reality, nearsighted individuals still develop presbyopia, though the required lens strength differs.
Dr. Zhang explains that nearsightedness involves clear vision for near objects but blurred vision for distant ones, whereas presbyopia causes blurred near vision while distant vision remains unaffected. Seniors without myopia who develop presbyopia need glasses only for near tasks, not distance.For those with pre-existing myopia who develop presbyopia, distance vision still requires myopic glasses, but near vision may not. This is because myopia and presbyopia can partially offset the "near vision" component. For example, someone with 600 degrees of myopia and 250 degrees of presbyopia would need 350 degrees of myopic correction for near vision after the 250 degrees of presbyopia are offset.Someone with 200 degrees of myopia and 200 degrees of presbyopia can read books and newspapers without reading glasses, yet they still have "presbyopia"—it's just that the lens power perfectly offsets it. Professional examination required before purchasing glasses Most seniors with blurred vision skip hospital checks and directly order glasses or even buy ready-made ones, which is actually very harmful."Dr. Zhang explains that prolonged use of improperly fitted glasses can not only cause serious eye diseases but also lead to symptoms like memory loss, dizziness, headaches, and poor sleep. "Elderly individuals must undergo an eye examination by an ophthalmologist to rule out age-related eye diseases before getting an accurate prescription. Based on the results, they should select reading glasses that suit their specific needs."
Presbyopia is partly linked to how eyes were used in youth; excessive eye strain can accelerate its onset. No one wants to wear reading glasses prematurely, so daily precautions are crucial to avoid chronic eye fatigue. Dr. Zhang recommends ensuring adequate sleep for thorough eye rest. Additionally, after about 50 minutes of close-up work, take a 10-minute break.Look away from computer screens or books and gaze into the distance. Perform office exercises or eye exercises, and move your neck. Consistent practice will yield benefits. 【Related News】 At 29, She Could No Longer Do Needlework—Turns Out She Had Presbyopia Liu, a 29-year-old employee at a knitting and embroidery workshop in Hangzhou, often worked late into the night doing needlework.A few days ago, she suddenly noticed her vision deteriorating—she couldn't even see the needle hole when threading. After a hospital examination, the doctor diagnosed her with mild congenital hyperopia. Due to this preexisting condition, her eyes' accommodative ability deteriorated significantly after frequent overuse, leading to premature presbyopia.
Cases like Liu's, where young adults develop presbyopia, have increased in recent years.Previously, presbyopia typically appeared in people over 45 to 50 years old, but now it has advanced by 10 to 15 years, with 35 becoming a threshold age.
In modern society, the prevalence of computers and televisions, coupled with extensive reading for work and daily life, keeps the eyes in a state of prolonged strain. This depletes the reserve energy of the eye muscles, ultimately leading to a decline in the eye's focusing ability. The result is premature presbyopia.
Pupil
Lens
Retina
Myopia
Concave lens correction
Excessively long anterior-posterior eye axis
A normal eyeball is roughly spherical. Its posterior wall houses the light-sensitive retina, while the front contains a biconvex lens.When focusing on near objects, the ciliary muscle contracts forcefully, causing the lens to become more convex due to its elasticity. Conversely, when viewing distant objects, the ciliary muscle relaxes, flattening the lens. This mechanism allows the eye to adjust its focal length, ensuring that images at varying distances converge precisely on the retina. Presbyopia Convex lens correction>Short Axial Length
During presbyopia, both the ciliary muscle's contraction ability and the lens's elasticity diminish. The lens can only maintain a relatively flattened state. Consequently, when viewing nearby objects, the focal point consistently falls behind the retina. What appears on the retina is merely a blurred circle of light that hasn't yet converged into a sharp image.