When eye doctors check the the back of eyes. why sometimes they can not see some people's retinas  clearly?

What is the problems cause you can see a person's retinas  clearly?

 

usually the person has bad eyes, but what is the problem?

5 hours ago, PeterBushMan said:

When eye doctors check the the back of eyes. why sometimes they can not see some people's retinas  clearly?

What is the problems cause you can see a person's retinas  clearly?

 

usually the person has bad eyes, but what is the problem?

The problem is, that you don't see...

2 hours ago, dimreepr said:

The problem is, that you don't see...

!

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This is NOT the philosophy section. If you can't help, don't post.

 

When an eye doctor looks at your retina, he is looking through several different layers.

The cornea is usually transparent, but it can have scarring or uneven curvature, making for a fuzzy view.
The aqueous humor is a liquid that fills the front part of the eye, most always clear, but hi-pressure of this fluid ( due to poor drainage ) is the cause of glaucoma and loss of optic nerve function.
The lens is next, and both the lens and its capsule can become cloudy. The capsule can be cleared with a YAG laser ( see Yag laser capsulotomy ), but once the lens becomes obscured, a condition known as cataracts, it is removed and replaced by an artificial lens ( one of the most common eye operations ).
Between the back of the lens capsule and the retina is the gelatinous humor, which can sometimes be occluded by traces of blood due to trauma of the eyes. Most people have experienced these 'floaters', but sometimes excessive trauma to the blood vessels feeding the retina can dramatically increase their numbers.

All of these conditions introduce screening that prevents the doctor from getting a clear view of the retina at the back of the eye.
( yes, I have glaucoma, had cataracts removed, and YAG laser capsulotomy )

On 6/28/2021 at 11:55 AM, MigL said:

When an eye doctor looks at your retina, he is looking through several different layers.

The cornea is usually transparent, but it can have scarring or uneven curvature, making for a fuzzy view.
The aqueous humor is a liquid that fills the front part of the eye, most always clear, but hi-pressure of this fluid ( due to poor drainage ) is the cause of glaucoma and loss of optic nerve function.
The lens is next, and both the lens and its capsule can become cloudy. The capsule can be cleared with a YAG laser ( see Yag laser capsulotomy ), but once the lens becomes obscured, a condition known as cataracts, it is removed and replaced by an artificial lens ( one of the most common eye operations ).
Between the back of the lens capsule and the retina is the gelatinous humor, which can sometimes be occluded by traces of blood due to trauma of the eyes. Most people have experienced these 'floaters', but sometimes excessive trauma to the blood vessels feeding the retina can dramatically increase their numbers.

All of these conditions introduce screening that prevents the doctor from getting a clear view of the retina at the back of the eye.
( yes, I have glaucoma, had cataracts removed, and YAG laser capsulotomy )

Thank you very much.