What happens as the eyes adapt to new RGP lenses?

I am currently on day 3 of wearing my new RGP lenses, after having
worn soft lenses on a daily-wear basis previously. The RGPs feel
awful, like there is grit in my eyes, but I understand that this is to
be expected with this type of lens and that my eyes will adapt over
the course of a few days. They do feel a little better after they've
been in my eyes for several hours, and they do seem better than they
were on day 1. I can see okay and my eyes are not the slightest bit
red--they just feel very irritated. My question is, what exactly is
happening to my eyes as they "adapt" to these lenses? Am I simply
becoming more desensitized to the discomfort, or is there some
physiological change happenings in the cornea that makes the lenses
less irritating?

Lothar

 

Did you just go straight into wearing them full time? I would have thought that
there would be a time build-up regime, as there was for hard - used to increase
those by 30 minutes a day from 30 minutes, if I recall correctly ...

J

 

According to the package insert for these lenses (Menicon Z), this is
the maximum suggested wearing time for these lenses for a new user:

DAY HOURS
1 4-8
2 6-10
3 8-14
4 10-15
5 12-all waking hours
6+ all waking hours

My doctor told me, without referring to the insert, that I should be
up to a full day's wearing time within 4-5 days (because I was already
used to wearing soft lenses), so his advice seems more or less
consistent with the insert. I wore them for 4 hours on day 1, and 10
hours on day 2 because they didn't feel too bad toward the end of the
day. Today though (day 3, now at 8+ hours), they feel worse than they
did at this time yesterday, although I've been out driving with the
windows open and shopping in air conditioned buildings, so they may
just be dry.

Incidentally, these lenses are approved for 30-day continuous wear
(like Focus Night and Day, to compare to a soft lens counterpart),
with extremely high oxygen permeability. They are an entirely
different animal than old-style "hard" lenses.

Lothar

 

Oh yes, I know that, but they are much more of a foreign object in the eye than
soft lenses. I would have taken minimum wear times and increases / day rather
than jumping from low to high hours / day.

Jim

 

Yes, that is probably what I should have done. I guess I was just too
impatient to stretch the adaptation period over too long a time, so I
went with the maximum recommended wear time for days 2 and 3. I
figured the discomfort was just normal for a new RGP lens and
something I simply had to tolerate as part of the adaptation process.
I suppose that was the point of my original question--I wanted to know
if the adaptation period was simply my eyes being desensitized to the
sensation of a foreign body in my eye, or alternately if there is some
physiological change happening to my eye that makes the lens more
compatible with my cornea. Anybody have any idea?

Lothar