"Roger Chapman" wrote in message
...
On 21/07/2010 19:06, Dave Baker wrote:
Went for a free eye test at Tesco in Slough today cos my 20 year old
frames
are broken and I need a new pair. Surprisingly my prescription hasn't
changed much more than a jot in nearly 35 years. Back in 1977 I was
minus
1.75 dioptres in both eyes (short sighted) with a touch of astigmatism.
The
astigmatism moved around a bit over the various tests over the years but
the
basic sphere correction has stayed the same. My old specs work just as
well
as they ever did. I thought eyes might get worse over time but apparently
not. I'm still minus 1.75 in both eyes and can still read the smallest
print
on the charts despite the inevitable eye lense hardening over the years.

Do other people find the same or do eyes generally get worse over time?

I am short sighted. When I was young I could use the same glasses for
reading and for distance. About 5 years ago I found that I had to take my
glasses off for reading and got myself a pair reading glasses purely for
wearing at the computer as the screen was just that little bit too far
away for perfect focus. I am not sure I need the reading glasses any more
which is a good thing as one of the arms has broken off. I do have trouble
reading small print.

As to my normal glasses my prescription has apparently got slightly weaker
over the years. I keep my newest pair for driving and use whichever is the
most available of several old pairs from years past. I think the oldest
pair is over 15 years old but memory being what it is it could just as
easily be over 25 years old.

As I understand it eyeballs tend to lengthen with age which helps the
short sighted but not the long sighted.

Other way round: myopia is when eyeball is too long for lens and focus point
comes before the retina:
http://en.wikipedia.org/wiki/Myopia

Presbyopia is the loss of visual accommodation with age and in 'normal'
persons this can make you need glasses for anything closer than a metre by
age 60. It is thought to be due to changes in the lens with age, and if you
were already short sighted your nearest accommodation moving out a little
can help: however, you may then find you can't thread a needle when you
could before. Us 4 eyes really can't win it seems.

http://en.wikipedia.org/wiki/Presbyopia

S