Eye Doc Question
 

I have a question for the eye docs here - optometrists, opthamologists.

I am veeery nearsighted. Without glasses, my eyes naturally focus at about 8 inches. Is it harmful to my eyes to view an iPhone screen without glasses at about 8 inches away?

No! You are simply taking advantage of your natural focal point. However, if you are using both eyes and focusing in at 8", the extra-ocular muscles involved in converging both eyes together to allow for binocular vision at that close range will suffer some strain after prolonged viewing. This is not harmful though.

John, I would suspect your RX to be in the -6.00 to -8.00 range?

Cheers!

Alex

OD -10.50 +2.00 093
OS -11.00 +2.75 092

Actually my natural focusing range might be more like 6 inches, I just checked.

I use one eye at a time when "close reading" the iPhone. The reason I do this close reading is that, on websites that are not mobile optimized, the text is quite small and at normal reading range using glasses.

My eyes have been terrible my whole life. It is interesting that, before glasses were invented, I would have been disabled.

I've been told I'm too bad for laser surgery. I'm not interested in it anyway, my presbyopia would require me to wear reading glasses regardless.

Last time I checked the research was "unclear" - you could get eye strain which means overwork of the muscles that focus by changing the shape of the lens. As you age the lens gets harder and more difficult to alter in shape.

Yeah but I'm talking about reading at a distance such that the focusing muscles are relaxed. The natural focusing distance. And using one eye only, so that the muscles that control eye direction are also relaxed.

True....I'm guessing that you're over 50 (slap me silly if I'm wrong jyl!) in which case you are also a Presbyope (age related farsightedness caused by the "hardening" of the Crystalline lens inside your eye) as well as being nearsighted (myopic) with moderate astigmatism. So at a working distance of 6" uncorrected (with no glasses on) you are not using your muscles that control accommodation (near focussing).

I think my natural focal point was more like 2 inches (uncorrected). Wore contacts for 30 years (never glasses, would have been the proverbial coke-bottle bottoms). One optometrist estimated me as 20-2000.
Had cataract surgery about 10 years ago, ended up with a distance eye and a -2 reading eye.
btw, it was a real treat to wake up in the morning and be able to see instead of stumbling to the bathroom to put the contacts in.
Jim

in that case I don't see how any damage could occur - you have a lens, an imaging area with 2 types of sensory cells, and muscles to change the shape of the lens

as always, I advise checking with a professional - your co-pay is likely 20 bucks or so

Not quite right RWebb.....

Aprox 75% of the refractive power of the eye comes from the Cornea and the remaining 25% comes from the Crystalline Lens. And in jyl's case, as he is Presbyopic, the cilliary muscles of accommodation have minimal effect.

50.9 y/o. Hanging on to that 0.1 as long as I can .

Amazing invention, glasses. Revolutionized life for many , many people. Eye docs have the highest benefit/cost ratio in the medical profession, as far as patients are concerned.

What happened to people with bad eyes, before corrective lenses were invented? In the Middle Ages and before?

Or was the incidence of bad eyesight lower then ?

They may not have lived long enough for eye problems to present.

Actually for someone with fairly high Myopia, there is an alternative to laser correction. Refractive Lensectomy could be an option. Essentially it's identical to Cataract surgery in that the Crystalline lens is removed and replaced with an IOL (IntraOcular Lens). The refractive power of this IOL would be measured such that it would essentially reduce your Myopia to a predetermined and desirable range to get it as close to Emmetropia (normal vision) as possible. You would, of course, then require glasses for reading after however.

Just another option out there.....in the end, do your due diligence however as you've only got one pair to live with jyl!

I would guess that eye shape is somewhat hereditary. My eye doctor says my optic nerve is very "interesting", and just like my fathers who she also treats. I told her I would much rather be medically "boring". You also have to watch for detached retinas with a long eye. No boxing or basketball without Kareem Abdul Jabbar glasses.
Someone with very poor eyesight probably had less of a chance to pass on their genes. So all kidding aside, the incidence was probably much lower.

I've heard of that. I heard that is what fighter pilots get. But I'm acceptably happy with my natural body and have no interest in any elective surgery. Well . . .

I was just curious jyl, with a prescription like that, your eye doctor must be a 70 year old Ophthalmologist that still uses ancient vision testing equipment....

Back in the 60's the global optical industry decided to switch to a "minus cylinder" lens design, whereby the cylindrical RX (your astigmatism correction) would be "ground" on the back of the lens, as opposed to a "plus cylinder" design which is ground on the front. This design greatly reduces lens thickness and weight. Plus cylinder lenses and the vision testing equipment that is calibrated to measure plus cylinder correction, if I recall, was pretty much obsolete by the late 60's...not that I've been practicing that long!

So your RX jyl, when transposed (converted) to a minus cylinder format would actually be:

OD: -8.50 / -2.00 X 003
OS: -8.25 / -2.75 X 002

So, in actual fact, you're not as "blind" as you think you are!:D

Alex

That's nice to know! Thanks.

John, I am up there with you in the -8s

I can recommend an ophthalmologist I think is awesome in Oakland, if that helps.

Actually you guys in the -8s will have a great advantage "optically" over the rest of us, as we age. When you remove your glasses to look at small print up close...6-8 inches away...the rest of us would need to use a 3x-5x magnifier to get the same magnification....so you guys have built-in low vision aids!:cool:

Do ya feel special now?!?

Good for close talking, too.