I echo Mel's response, you are a gem. Thanks for your patience with all our questions. : )
thanks sooo much doctor for putting up with my incessant questioning ... you're a gem!
mel: thats what i've been thinking about you...some sort of entopic phenomenon.
heartygirl: what could cause a 1 D change? in someone over say 20 years old (like you), probably nearpoint stress. do you do a LOT of reading/studying/computer use? that would be one of the best-case scenarios, b/c it would mean there was no disease process causing the change. it is unlikely that as an adult your eye is "still growing" (juvenile myopia progression).
other (less likely but certainly possible) things that could cause refractive error change in adults:
-keratoconus (inherited corneal degenerative process)
-diabetes or other systemic or blood volume disorders
-thyroid eye disease
there are many more...
Thank you for your answer. I will probably go ahead and go thru with the dilating, I feel much better about it after reading your comments.
If you read this, what could be the causes of a 1 diopter change in vision?
hmmm, not sure ... i had my head resting on/against something, i definitely wasn't looking down, but i can't recall whether it was a flat screen or dome-shaped. pretty sure the dots were green and instead of just hitting the button when i saw a light, i had to hit it the corrresponding number of times ... (between one and four). does that sound familiar???
it was negative, but didn't seem to be a very "sophisticated" VFT - brief, just a few largish green lights, as opposed to numerous little white pinpricks of light ... would that matter terribly???
we have such interesting banter! i tell you!
"large-ish green lights"...havent seen THAT one. i know most types of visual fields out there, and i dont recognise that type.
there is a very common one called a frequency doubler (FDT) that you lean down and look into that has large-ish GREY lights...could that be the one you had?
if it was just a screen, a threshold (longer, more detail) wouldnt hurt in someone complaining of visual symptoms
if the visual field was CLEAN (no defects) then no, no matter where it was or who did it, you probably dont need another one.
if the visual field showed defects, then yes, you need another one to determine if the defects are "repeatable" or not
YES!!! thats the machine i own! a dicon. great machine, seriously. what threw me was the "large-ish" part of your description.
yes, the only machine where you "count the number" of green lights between 1-4 is on a dicon. you followed a red light around and counted green lights that flashed? thats a great machine. if you passed any of the dicon tests, you are fine. you do not have a visual field defect.
yay for me!!! so it's a good test? that's reassuring - maybe it is some kind of entoptic thing then ... the spot is there all the time but kind of flashes in a streak when i blink. it is also more noticeable when i squint or push against my eye (I can even see it with my eye shut when i do that) ....
thanks, doctor. sorry, i posted that question in the wrong place ... i shoud have made my question more specific also .... i had a VFT at the optometrist's, so i am wondering if there is any need to have another one with the specialist???
the original post was about dilation eye drops, not visual field tests. those are different.
a dilation uses eyedrops to make the pupil larger so the doc can see otherwise-unseen peripheral retina.
a visual field test is usually undilated and asks the patient to click a button when they see lights that the machine projects into their peripheral vision.
but i guess to try and answer your question: YES most visual fields are very similar no matter who performes it. the doc hardly ever performs a visual field test...most of the time a tech does it. a doc *must* perform a diliated eye exam, no tech is qualified.
is the visual field test done by an optometrist the same as the one that would be done be a specialist?
1) no, the most common dilation eyedrop is tropicamide...it is not a stimulant. it temporarily and harmlessly paralyzes a specific muscle in your eye (iris sphincter)
2) tiny amounts of tropicamide may be absorbed in your bloodstream (but may not be). it is not dangerous. we dilate people on those types of medications on a daily basis and no one ever has a problem
3) YES you need to be dilated if your rx really did jump 1 diopter. you are at little or no risk of tachycardia IMO
4) it is in the realm of possibility that your Rx jump is b/c of some retinal or disease problem. w/o dilation no one would know one way or the other.