text is very blurry

Frances:

The question that you’re asking is quite general in nature.

People on the Adobe Community forums will interpret your question differently, and will give a range of responses. Most of those responses will probably have to do with computer hardware or software configuration.

However, I suspect that you may be asking about something else: why does it become more difficult to read text the older we get? If that’s what you’re asking about, the answer below describes the major reason: an eye condition that everyone develops called ‘pres·by·o·pi·a’.

Presbyopia literally means ‘old man eye’: from the two classical Greek–Latin words ‘presbus’ (old man) and ‘ops’ (eye). It’s a normal part of life, although most people start noticing it in middle age. The simple reason: you can no longer comfortably hold and read standard text, because your arms aren’t long enough to keep it in focus.

The human eye is marvellous and sophisticated. Two of its critical parts are a flexible clear lens, and a ring of ciliary muscles that surround the edge of the lens. When these ciliary muscles are relaxed, the lens is flattened, and your vision focuses far away to the horizon. When the ciliary muscles contract, they force the lens to bulge, allowing you to focus on close objects.

Throughout your life, your body grows, adapts, and changes. So does the eye and all of its components. The eye’s lens is filled with a combination of organic compounds, mostly clear proteins. As you age, these proteins change in structure, making the lens less flexible. The ciliary muscles that surround the lens also weaken.

The result: it becomes increasingly difficult for the lens to bulge – that is, focus on nearby objects – an you progressively lose your near-focus vision. That’s why standard body text held at arm’s length becomes more blurred, the older you get.

How does your near-focus vision change with age? Everyone’s slightly different, but here’s a general guide:

• 0–10 years ≈ 20–10 dioptres* = 5–10 cm
• 10–20 years ≈ 16–8 dioptres = 6¼–12½ cm
• 20–40 years ≈ 12–4 dioptres = 8⅓–25 cm
• 40–50 years ≈ 8–2 dioptres = 12½–50 cm
• 50–70 years ≈ 4–1 dioptres = 25–100 cm
• 70+ years ≈ less than 1 dioptre = 100+ cm

[* Optics professionals use a measurement unit called the ‘dioptre’, which is an inverse-metre. If you’ve been given a prescription by an eye doctor, the numbers are typically in dioptres.]

The average person in their mid-forties can focus as close as 2 dioptres (50 cm). By their mid-fifties, the average person’s close focus is down to 1 dioptre (100 cm): just beyond arm’s length.

When your near-focus vision drops below 1 dioptre, you lose the ability to clearly see anything closer than one metre from you: an immensely frustrating experience, especially that phones with tiny screens and tiny text have become the norm. Rest assured: anyone older than sixty years will experience this, so you’re not alone.

What can you do about it? Fortunately, the solution is simple and inexpensive. If you visit any optician, wholesale warehouse, supermarket, pharmacy, bookstore, news agent, arts and crafts store, hardware store, et cetera, chances are good that there’ll be a rack of reading glasses on a counter somewhere. A decent pair of reading glasses should cost no more than a few dollars, and they should be available in a wide range of strengths.

How do reading glasses work? They’re simply magnifying glasses, disguised as eyeglasses. Reading glasses strength is normally measured in dioptres, starting at around +1.00 dioptre, and stepping up in strength by 0.25-dioptre increments.

How do you choose which strength of reading glasses is best for you? That’s a matter of personal choice. For example, let’s say that your current near-focus vision is 1 dioptre (100 cm = 1 m):

• If you choose reading glasses with a strength of +3.00 dioptres, you’ll be changing your near-focus vision from 1 dioptre (100 cm = 1 m) to 4 dioptres (25 cm = ¼ m).

• If you choose reading glasses with a strength of +2.00 dioptre, you’ll be changing your near-focus vision to 3 dioptres (33⅓ cm = ⅓ m).

• If you choose reading glasses with a strength of +1.00 dioptre, you’ll be changing your near-focus vision to 2 dioptres (50 cm = ½ m).

Please note that presbyopia is the most obvious cause of blurred vision as you get older. But it isn’t the only cause. There are other conditions – like cataracts and glaucoma – that have different consequences. Some of these conditions can be quite serious, and may cause permanent blindness. That’s why it’s recommended that you visit an eye doctor for regular examinations, just like you’d visit your dentist.

I hope that answers your question. If not, please let me know.

Best regards
Andrew

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We need more information. In what app or where is the text blurry? A screen shot may help.