What worsening vision is and how it shows up
Worsening vision means objects look blurry or double, are hard to see far away or up close, or your field of view has narrowed. The cause can lie in the eye itself, the optic nerve or the brain, so how it happened and how fast matters. Vision that fades over months is more often a matter of glasses and age. A sudden drop, especially in one eye, calls for urgent care. A diagnosis cannot be made from a text.
Vision gets worse gradually
The most common cause is a refractive error: nearsightedness, farsightedness or astigmatism. After 40 to 45, almost everyone develops age-related farsightedness and has to hold small print at arm's length. Slow blurring with halos around lights and glare from headlights at night points to a cataract, a clouding of the lens. Glaucoma, raised pressure in the eye that damages the optic nerve, can go unnoticed for a long time and narrows the field of view first, so it is found at an exam rather than from complaints. With age-related changes in the retina, straight lines look bent. It is better to catch all of these before your vision drops.
Vision got worse suddenly
Sudden blurring, loss of part of the field of view or a curtain across the eye is a reason not to wait: go to the emergency department or call 112. Retinal detachment, a blocked retinal vessel, an acute glaucoma attack, inflammation of the optic nerve and sometimes a stroke can look like this. If vision changes come with weakness in an arm or leg, a drooping face or trouble speaking, it is an emergency. The sooner treatment starts, the better the chance of saving sight.
Blurry vision after screens and in the evening
If your vision blurs in the evening or after long computer work, the cause is often tired, dry eyes: you blink less and the eye tires quickly. Breaks and moister air usually help. But if it persists, check whether you need glasses. For redness and burning, see Red eyes, and for general weakness, see Fatigue.
Blurry vision with headache and dizziness
Migraine sometimes starts with visual effects such as flashes, zigzags or blind spots, and they usually pass within an hour. But vision changes with a headache that happen for the first time should be checked by a doctor. Blurring together with a sudden severe headache, dizziness or numbness is a warning sign. More on Headache and Dizziness.
Vision changes with diabetes and pregnancy
In diabetes, sharp swings in blood sugar can blur vision for a while, and over time damage the vessels of the retina, so people with diabetes need regular eye checks. In pregnancy, sudden blurring with a headache or swelling needs urgent assessment, because it can be a sign of high blood pressure.
Worsening vision in a child
A small child will not say that they see badly. Look for squinting, sitting close to the TV, tilting the head, rubbing the eyes, headaches after reading, crossed eyes and poor school results. A child should see an eye doctor even before complaints, especially if the parents have poor vision. If vision drops suddenly or there is pain, help is needed urgently.
What you can do before the visit
- If your vision dropped suddenly, do not wait for it to "pass": go to the emergency department or call 112. It is better not to drive yourself.
- Write down when it started, whether it is one eye or both, gradual or sudden, and what else bothers you.
- Bring your glasses or lenses and a list of your medicines.
- Take breaks from screens, blink more often and light your workspace well.
- Do not pick glasses or drops yourself by guesswork.
How an eye doctor finds the cause
The doctor checks visual acuity on a chart and fits a correction, then examines the eye under a microscope and the back of the eye, usually after widening the pupil, after which it is better not to drive for a few hours. The pressure in the eye may be measured, the visual fields checked and an optical scan of the retina done. If the cause may lie outside the eye, you may be sent to a neurologist or an endocrinologist. Treatment depends on the cause: sometimes glasses are enough, sometimes drops, laser or surgery are needed.