Questions tagged [eye]

Questions related to diseases that affect the eye, visual acuity, lenses and glasses.

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19 views

What is the use of this green and red lines on Snellen/Eye chart?

Eye read that in eye tests red and green colors are used. For example: But in Snellen/Eye chart, these are not background colors. These are lines only. What is the purpose of it?
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1answer
20 views

What would be visual acuity of a person if he can can read all letters of 20/25 and most of 20/20 on Snellen chart?

Suppose this is the Snellen chart: And you measure your normal visual acuity using correct rules (i.e., placing it at 6 meters distance, in observation of an examiner in hospital. And suppose you can ...
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27 views

Is there an objective method to know the degrees of nearsightedness or farsightedness?

Is there an objective method to know the degrees of nearsightedness or farsightedness? The current method for eye tests is to ask the patient to read numbers/letters, then the ophthalmologist puts ...
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6 views

Corneal wavefront measurement using Hartmann-Shack sensor

When using a Hartmann-Shack sensor to measure wavefronts from the eye, what is precisely measured? The cornea topography only or also information about other eye components like lens, retina, and so ...
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1answer
171 views

Why do optometrists recommend dilation when the power of a lens can be measured even by a ruler?

I don't understand why optometrists dilate your eyes, which is a very annoying thing, when eye power can be measured by just a ruler at your home as suggested by this, which just uses a 100/(distance ...
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17 views

Home eye sight test for myopia patients? [closed]

I am a 16 year old and have been diagnosed with myopia since I was 8. I apologise for using wrong terms in advance, since I am not too familiar with medical terms. I wish to become a software engineer,...
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18 views

Is the common saying that sitting close to a screen regularly can cause short-sightednes backed by medical science?

How true is this? Should I be cautious as I spend too much time in front of a laptop screen? I already have glasses with power 0.5 and 0.25, ( this was 3 years ago, I haven't tested recently) but I ...
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23 views

Is it safe to see smartphone first thing in the morning? [closed]

Well, I'm a student and have many interesting things to learn, but not enough time. So, one thing I'm trying is that I pick one of the things that I really want to learn, but can't make time for, then ...
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25 views

Hyphema type that doesn't pool?

I'm gonna be honest here, I'm writing a story where a guy has the classical evil red eyes you can find everywhere, and I want to base it in science. I've thought about posting this on worldbuilding, ...
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1answer
45 views

Can colorblind people see any types of images that normally sighted people have a hard time with?

Could one devise a first image that contained a "hidden" sub-image where said sub-image is such that colorblind people would typically have an easier time seeing said sub-image embedded ...
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1answer
27 views

Why is monocular diplopia a symptom of astigmatism in some cases?

I have read that patients suffering from astigmatism sometimes experience monocular diplopia but I don't understand why this is. Do we have an idea of why this occurs?
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25 views

Light adaption of pupil. When is a size adaption normal? [closed]

If an eye gets lighted with a flashlight or other light sources the pupils will decrease their width. This pupillary response is a typical indicator in diagnostics. Is there any specific value which ...
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27 views

What is this procedure for eyes using electic impulses?

I am wondering what this device is called and what it is supposed to do. When I was a kid I was short-sighted (still am) and my parents tried a few treatments that could possibly improve my sight. One ...
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9 views

Which part of lens is involved in refraction?

I'm reading about cataract and various morphologies related to it. Some of them are visually significant cataract some are not. I'm unable to understand why it is like that. For example punctate ...
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8 views

How viral corneal ulcers due to HSV produce loss of sensation but painful at same time?

HSV= Herpes Simplex Virus So, while reading about HSV keratitis I've come across a confusion, Dendritic ulcers of HSV produce extremely irritating ulcer (Parson 22ed pg180) dendritic ulcers of ...
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27 views

Is it harmful to touch/inhale soaked/liquid printer ink? [closed]

I have been printing a lot of work last night, but I accidentally placed my printed stack of paper (5 pages back to back filled printer ink) on top of a shelf below my air conditioner, next to me and ...
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1answer
71 views

Why do the eyes need to be closed during sleep to regain moisture?

I've noticed that if I don't sleep for a long time, my eyes get dry, and no amount of moisture helps to moisturize them. I moisturize every 10 minutes and it doesn't help. The answer is sleep. Our ...
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1answer
76 views

Can watching lightning be dangerous for one's eyesight (assuming not directly or indirectly hit by the lightning strike)?

Watching the sun can cause eye damage. Can watching lightning be dangerous for one's eyesight (assuming not directly or indirectly hit by the lightning strike)? The only study I have found so far, {...
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11 views

What is “adaptive optics retinal imaging”?

A paper says To validate the effectiveness of using A-GAN for data augmentation, we assessed its performance on cell analysis in adaptive optics retinal imaging, which is a rapidly-changing medical ...
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1answer
37 views

What is the difference between fundus image, fundus photography and retinal image?

I see these three terms in some papers in the field of medical images. Google gives this kind of images for any of them, which indicates they pretty much mean the same thing. Are they the same ...
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37 views

Meaning of colored ring around iris

There seem to be various conditions that affect the color of the outer edge of the iris, such as: Fleischer ring - Wikipedia Arcus senilis Kayser–Fleischer ring Limbal ring and I imagine there are ...
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1answer
34 views

Can eyes really move “in and out”?

A tutorial says outside of the globe or the orbit we can see the ocular motor muscles which control the movement of the eye those control left-right up-down in and out and allows the eye to ...
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1answer
24 views

medical meaning of “Meridian”

A video tutorial is using a spoon to explain how astigmatism occurs. the cornea ideally should be perfectly round like a ping-pong ball which is a perfect sphere and has the same curvature in ...
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42 views

How is micro debris cleaned from the eye in unusual cases?

Sometimes micro debris or "microparticles" are interacting with human's (and animals's) eyes: It can be some types of dust or hair pieces trimmed with a trimmer; I especially mean little particles of ...
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1answer
106 views

Why can't we just close our eyes periodically to reduce eye strain?

The 20-20-20 rule I've heard is to stare at something 20 feet away, for 20 seconds, every 20 minutes to help reduce the strain of looking at things up close all day for those of us who need to look at ...
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25 views

Are focus-related eye diseases like myopia and astigmatism reversible? [closed]

Are those diseases recoverable without surgeries, glasses or contact lens? Maybe by eye exercises? Edit: Once I saw on YouTube a man that managed to recover his eyes from these conditions by eye ...
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1answer
59 views

Can myopia be treated by applying pressure?

I have high myopia in my right eye (~7.00). I've noticed that unsystematically applying pressure onto certain areas of the eyelid onto the eye can actually bring the power down to about 3-5.00 (by ...
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69 views

Does the use of eye glasses prevent eye disease?

I'm turning 40 and went for my first eye test recently. They said I have nearsightedness. I work on a computer all day. They gave me three quotes for eye glasses : Option 1: (Cheapest price) 1.1 ...
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22 views

Is there a way to protect eyes from negative effects of computer and mobile screen? [duplicate]

People who work on computer and smartphone during most hours of the day are prone to impacts of the light of these screens. I have read about the negative effects of the light from screen. So I was ...
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1answer
40 views

How our brain discharge old CSF? [closed]

Our brain produces new CSF fluid every hour, so old CSF discharge from our body. My question is where is CSF discharge point? or how our brain discharges Old CSF from the brain. . There is a ...
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0answers
42 views

Does corrective eye surgery for affect the ability to focus similar to corrective lenses?

If corrective lenses adjust the point at which the eyes focus and, for a strong correction, inhibit the ability to focus at the opposing distance, will corrective eye surgery affect vision in the same ...
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2answers
45 views

What is the name of a condition where one cannot/can poorly perceive depth for objects moving towards them

I remember a case where someone apparently had great difficulty perceiving the distance of an object if it was (quickly) travelling towards them. Their depth perception was otherwise fine, but when, ...
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1answer
123 views

What are the official eye colors?

In reading the wikipedia article on eye color, I noticed that the colors listed there seemed a bit arbitrary. Tangentially, I know that even the words we use today to recognize colors are neither old ...
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0answers
35 views

Does wearing UV blocking glasses worsen myopia in children?

I have found this article which claims (for chicken) that blocking outdoors UV light made myopia worse. Some kids require glasses from a young age, e.g. 6 years old. Most of these glasses do have UV ...
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23 views

Eyelid thickness variation

I am working on a project in which I have to measure inter ocular pressure (IOP) of the eye. Currently, the gold standard to measure IOP is using goldmann applanation tonometer, in which anesthesia is ...
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0answers
30 views

Does playing wind instruments cause damage to the eyes overtime?

Found some studies that investigated the IOP's relation to wind instrument playing: one two three. I'm curious because I thought wind instrument playing (as over time it takes endurance to control ...
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563 views

What are those circles and lines I see when I squint at light?

what are those things I see? It happens when I look at a light source (Such as a light bulb) and the circles are supposed to be smaller on the picture. (I recreated what I see)
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1answer
54 views

Does staring at a screen for long periods of time cause myopia?

My uncle once told me "the real reason myopia happens because you look at a PC monitor non stop for hours. When you look to the same object for hours, the eye muscles gets used to the focusing close ...
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0answers
90 views

Is the increased intraocular pressure from playing wind instruments damaging to the eye?

People who play wind instruments often practice for hours every day. Some studies (this one as well) mentioned that intra-ocular pressure (IOP) raises during play. Some other studies measured a raise ...
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1answer
79 views

How to reduce the side effects of wearing contact lens? [closed]

This explains a lot of side effect of wearing contact lens. The type of contact lens Iam talking about is silicon hydrogel lenses. Questions: 1) Till how many hours can lens be worn continuously? 2)...
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1answer
185 views

Abnormal shrinkage of the eyeball

Is there a condition which describes an abnormal shrinkage of the eyeball? That is, a counterpart to buphthalmos (an abnormal enlargement of the eyeball).
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33 views

Is it normal for it to take more than 3 weeks to get used to astigmatism correcting glasses?

Is it common or realistic in the optometry industry to suggest to someone that it may take 6 weeks to adjust to new glasses?
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2answers
102 views

Which one is better? Reading on a computer, on a tablet, or on paper?

I'm a graduate student and I have to spend a lot of time on reading research papers everyday. My question is which of the following is the best choice for eye health? I can either read them directly ...
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2answers
42 views

Is there an antagonistic pair of muscles in the eye? [closed]

One to shorten the lense for near focus, one to lengthen it for far focus? Or is there a single "ciliary" muscle that is either engaged or not?
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62 views

Does wearing glasses while on the computer increase myopia?

Nearsightedness is prevalent in demographic groups that look at screens for most of their time, such as office workers or students. (Saw et al., 2002) Glasses correct the defocusing of the lens in the ...
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1answer
30 views

How to diagnose myopia in a 2-year old?

Is there an exam that clearly diagnoses a child myopia level without the need of this child's feedback (as he is not going to give it, given his age (2))? Like, is there a laser exam or something ...
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16 views

Factors Scientifically Shown to Affect Myopia

What are the main factors that have been reasonably established to affect myopia? For example, here is a study which shows that children who spend a lot of time outside have far better eyesight than ...
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2answers
46 views

Can spine misalignment be responsible for eye conditions?

Can some eye conditions be explained by a problem in a given spine vertebra? We know that the spine is connected to the nervous system, I already saw some charts connecting each vertebra to an organ ...
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1answer
141 views

The next generation of contact lenses

My eyes have the problem of keratoconus and the last 10 years I live using rigid gas contact lenses. The last years piggy-backs. But I am not so satisfied with the precision and accuracy. To be more ...
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25 views

Eye Chart Lighting for Consistency?

If the goal is consistent test results and controlling for distance is a given, then would a backlight in a dark/darkened room guarantee the most consistent results? Is there any other way to control ...