Vision naturally changes with age as eye structures gradually age. Presbyopia, a physiological process, occurs when the eye's lens progressively loses elasticity, making it difficult to focus on close objects. According to Master of Science, Doctor Le Thanh Huyen of the High-Tech Eye Unit at Tam Anh Cau Giay General Clinic, individuals with presbyopia struggle to see near objects clearly, often needing to hold books or phones further away. They also require more light for reading and experience eye strain after close-up work. This condition typically begins around 40 years old and can be corrected with reading glasses or appropriate corrective lenses.

However, if blurry vision extends beyond near vision to affect distance vision, appears in one eye, progresses rapidly, or is accompanied by other unusual symptoms, it may indicate various underlying eye conditions.

**Cataracts:** Patients may experience hazy vision, as if looking through a fog, poor vision in low light, light sensitivity, or glare, especially when driving at night. Colors might also appear yellowish or brownish, and vision gradually declines over time.

**Glaucoma:** This condition often progresses silently, damaging the optic nerve and potentially leading to vision field loss if not detected and treated early. In the early stage, patients may notice almost no abnormalities. Some cases of acute glaucoma can manifest suddenly with severe eye pain, red eyes, blurry vision, halos around light sources, headache, and nausea, requiring emergency medical attention.

**Macular Degeneration:** This disease affects the central region of the retina, making it difficult for patients to see fine details, read text, or perceive images without distortion. Doctor Huyen notes that one indicative sign is when straight lines, such as doorframes, table edges, or lines of text, appear curved or bent.

A healthcare worker is measuring a woman's vision. Photo: Thiet Tru

**Diabetic Retinopathy:** This condition can progress for a long time without causing clear symptoms. In its severe stage, patients may experience blurry vision, numerous black spots or "floaters," distorted straight lines, and reduced vision. Therefore, maintaining good blood sugar control and undergoing regular eye examinations are crucial, even if vision appears relatively clear.

Beyond these conditions, refractive errors such as myopia, hyperopia, astigmatism, dry eyes, or certain corneal diseases can also diminish vision. Dry eyes, in particular, often cause fluctuating blurry vision, a gritty, burning, or hot sensation in the eyes, or the feeling of a foreign body. Vision sometimes improves after blinking or using artificial tears.

Doctor Huyen advises individuals aged 40 and older to proactively check their vision and undergo regular eye examinations, especially if they have risk factors such as a family history of glaucoma, diabetes, hypertension, or previous eye conditions. The frequency of examinations depends on age, health status, and individual risk.

It is advisable to maintain good control over blood sugar and blood pressure, limit smoking, wear UV-protective eyewear, and adopt a balanced diet. When vision changes abnormally, patients should not delay an eye examination simply by assuming it is a sign of aging and then self-prescribing glasses for extended use.

According to Doctor Huyen, reading glasses can improve presbyopia but cannot treat conditions that damage the cornea, lens, retina, or optic nerve. An eye examination helps accurately identify the cause and determine the appropriate corrective or treatment method.

Trinh Mai