Talk:Hyperopia

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you actually got it wrong. Longsighted means you can see further away than normal people. please correct this sight immediately! cf —Preceding unsigned comment added by 82.23.15.235 (talk) 20:25, 2 October 2007 (UTC)


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[edit] Lens correction diagrams are incorrect

The lens correction diagrams in this article and the Myopia article are incorrect. They show the outer light rays passing into and out of the lenses without being refracted. The light rays then 'magically' focus on the retina after they pass through the cornea. 80.177.217.228 23:40, 8 August 2007 (UTC)

I agree, the diagram is very poor. It seems to be intended as a purely symbolic diagram showing "Hyperopic eye = Incorrect focus" vs "Convex lens + Hyperopic eye = Correct focus". Because the rays of light are traced on the diagram as going straight through the convex lens however, it ends up being very misleading and confusing. A corrected diagram should depict the rays bent a small amount by the convex lens, then bent again by the eye's lens, resulting in the proper focus. --Cecilkorik (talk) 21:48, 20 November 2007 (UTC)

[edit] Article Improvement Drive

Contact lens is currently nominated to be improved on Wikipedia:Article Improvement Drive. Please support the article with your vote. --Fenice 10:51, 16 January 2006 (UTC)

[edit] Hyperopia and presbyopia

Regarding: "Hyperopia is closely related to, or a typical symptom of, presbyopia (literally, old vision, and also sometimes called farsightedness), the inability to change focus of the eye sufficiently in older people.[1]" I initially removed this remark as "not really accurate", but it was restored with the comment, "please make it more accurate if you can, rather than deleting it; the ref'd book is on google books". It may be possible to make an inaccurate remark accurate, but an inaccurate remark cannot be made "more accurate". This is why this particular remark is beyond salvaging:

  1. The statement does not make clear exactly how hyperopia and presbyopia are "closely related."
  2. Hyperopia is not a "symptom" of anything. "Trouble focusing" or "blurry vision" are symptoms, but hyperopia is a physical condition of the eye. Presbyopia is a different physical condition.
  3. Those who call presbyopia "farsightedness" are generally misinformed laymen. I do not see where the authors of the cited book call presbyopia "farsightedness".
  4. The referenced book addresses similarities in the surgical correction of certain hyperopes and certain presbyopes. The examples that come to mind are a 35-year-old +2.75 hyperope (who will probably report blurriness far and near) and a 50-year-old +0.50 hyperopic presbyope (who will probably report blurriness only at near). Conversely, a 35-year-old +0.50 hyperope would likely not be symptomatic at far or near, and a 50-year-old -2.75 myopic presbyope would likely report only blurriness at far. -AED 03:56, 19 September 2006 (UTC)
It would be useful if someone like you who has a clear understanding of the relationship could explain it better. I know something about optics, and a bit about medical terminology, and I know that both conditions are sometimes called farsightedness (yes, mostly by lay people) and are often addressed with positive lenses. In both cases, people focus more easily on far things than no near things. And yes I know they are different things. But for the article to be silent on the relationship is inappropriate, especially since they are so often confused or used interchangably by lay people. That's why I put it back with a request for you to make it "more accurate", by which I probably meant "more nearly accurate" if that suits you better. Thanks. Dicklyon 13:03, 19 September 2006 (UTC)
Done. The new citation might help to explain some of the confusion. -AED 06:31, 20 September 2006 (UTC)
"Often confused with" is not a sufficient statement of the relationship. I'll try to put some in. Dicklyon 12:37, 20 September 2006 (UTC)
What is the "relationship" that you are claiming exists? It seems that you are attempting to establish one based on the presentation of symptoms. Near blur is a symptom that occurs in some presbyopes, some hyperopes, and some myopes. Similarly, far blur is a symptom that occurs in some presbyopes, some hyperopes, and some myopes. Observing the symptomatic similarities of certain hyperopes and certain presbyopes is not a "relationship".
Regarding the addition: "Presbyopia is also sometimes referred to as farsightedness, since in otherwise normally-sighted persons it makes it more difficult to focus on near objects than on far objects." I do not see where "presbyopia is also sometimes referred to as farsightedness" in the book that was cited. The essence of the statement is that "otherwise normally-sighted persons" (i.e. emmetropes) see well far-away. -AED 19:42, 20 September 2006 (UTC)
The intro paragraph to chapter 2, p.17, says its about "the interrelationships between hyperopia and presbyopia." I have no doubt you'll be able to summarize it better than I have. Dicklyon 20:03, 20 September 2006 (UTC)
The "interrelationship" is that uncorrected hyperopes experience near blur as they become presbyopic. It does not say that presbyopia is synonymous with "farsightedness". -AED 20:55, 20 September 2006 (UTC)
Of course not. Nor did I. But uncorrected emmetropes also experience near blur as they become presbyopic, somewhat like younger hyperopes do. Dicklyon 21:27, 20 September 2006 (UTC)
You did not explicitly state "presbyopia is synonymous with 'farsightedness'" but you did write "Presbyopia is also sometimes referred to as farsightedness". I fail to see how that comment is "a sufficient statement of the relationship", particularly if the authors in the citation it links to did not state it. I'll try to add something they did say and you can let me know if it's providing the information you want it to provide. -AED 00:37, 21 September 2006 (UTC)

Here's one that does refer to "presbyopia...farsightedness due to aging" [1] They are not hard to find, though in a minority. Here's one that says "Hyperopia is different from Presbyopia, which is far-sightedness which develop as you grow older." [2] (I am not making this up) Dicklyon 01:37, 21 September 2006 (UTC)

The primary difference from those references to what we have here is the addition of "...due to aging" or "...which develops as you grow older". Given that up to 25% of presbyopes have myopia (i.e. they see better close than they do far away) and another 15 to 25% have enough hyperopia to blur distance vision, it's still not an accurate way to describe presbyopia. I think you'll find in your search that most eye care professionals will not describe presbyopia as farsightedness or they will point out why the two should not be confused. -AED 03:40, 21 September 2006 (UTC)
Yes, I agree. My guy told me I have myopia with a little presbyopia, which was the first time I realized that presbyopia was not the proper term for farsightedness, even though it is often called that. The point is to point out that hyperopia and presbyopia both have farsightedness (or near blur) as a typical symptom, and they both are (sometimes) called that, in spite of the important difference between them. Plenty of books make the connection, so we should be able to do so here, too. No shortage of verifiable sources. Dicklyon 11:39, 21 September 2006 (UTC)

Thanks, AED, you've done a good job of it. Dicklyon 13:17, 23 September 2006 (UTC)

[edit] Longsightedness?

I was just doing a bit of casual reading about eyesight, and I noticed that Longsighted doesn't exist yet Farsighted redirects to this article. From what I understand, the two refer to the same thing (like Nearsighted and Shortsighted that are both synonyms that redirect to Myopia) so would it perhaps be a good idea to get Longsighted to redirect here? Zephonith 14:43, 7 June 2007 (UTC)

Longsightedness is not really that common. I never learned about the term until I went to see an optician for the the first time in my late 30s, to hear her tell me that the fact that I could see very well far and badly close was "longsightedness", sometimes a side-effect of hyperopia (a lot of people are diagnosed with hyperopida later in life). People with longsightedness seem to be able to see very well very far and to have to strain close. I guess we need confirmation of this fact. It is my case. For instance my 19-in screen is at 4-feet from my eyes and that's just fine. --WhiteEcho (talk) 01:16, 26 December 2007 (UTC)

[edit] underwater vision for humans

http://www.deepocean.net/deepocean/index.php?science02.php: (...this means under water, we are extremely far sighted...)

Does one know if wearing highly corrective contact lenses could restore a correct underwater vision without a mask? (free-divers do use special devices because they cannot expel the mask air).

See also: Underwater vision, Diving mask, Free-diving

Skwa 16:46, 26 August 2007 (UTC)