Basic Eye Anatomy


Basic Eye Anatomy
Light enters the eye through the cornea, the clear layer covering the front of the eye. The cornea works with the lens of the eye to focus images on the retina. The upper and lower eyelids protect the eye from injury, with the eyelashes forming a protective barrier.

External and Internal Eye Anatomy
The cornea allows light to enter the eye. As light passes through the eye, the iris changes shape by expanding and letting more light through. Or, it constricts and lets less light through to change the size of the pupil. The lens then changes shape to allow the accurate focusing of light on the retina. Photoreceptors in the eye transmit nerve signals through the optic nerve to the brain. The brain processes these nerve impulses into sight.



Lateral Eye Anatomy

The cornea is the clear watch glass covering in the front of the eye. The cornea works with the lens of the eye to focus images on the retina. The retina captures the image and sends it to the brain to be developed. The retina is normally red due to its rich blood supply.


Anatomy of the Eye Lens
The lens is responsible for making sure light rays come to a sharp focus on the retina. The lens of the eye is normally clear. If the lens becomes cloudy or is opacified, it is called a cataract.

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Retinoscope

Retinoscope

An eye doctor looks into your eye with a retinoscope.
A retinoscope is used to shine light into a patient's eye for an eye doctor to observe the reflection off the retina. The light is moved back and forth across the pupil. A retinoscope is especially useful in prescribing corrective lenses for patients who are unable to give oral feedback to the eye doctor. It is also useful for determining how well the eyes work together, or accommodate, to see clearly.

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Direct Ophthalmoscope

Direct Ophthalmoscope

A direct ophthalmoscope is a hand-held instrument.
A direct ophthalmoscope is a hand-held instrument used for examining the interior structures of the eye, especially the retina. It consists of a mirror that reflects light into the eye and a central hole through which the eye is examined.

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Lensometer

Lensometer


A lensometer determines the prescription of a pair of eyeglasses.


A lensometer is an instrument used to measure the power of an existing lens. An optician uses a lensometer to determine the prescription of a patient's eyeglasses.

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