The colored part of the eye that helps regulate the amount of light that enters is called the:
The colored part of the eye that helps regulate the amount of light that enters is the iris. Other parts of the eye and their functions are:
Cornea: the transparent, protective front part of the eye that refracts (or bends) light and helps you focus
Pupil: the hole in the center of the iris that regulates how much light is let into the eye
Lens: a transparent, biconvex (curved outward on both sides) that helps light focus onto the retina
Retina: a nerve layer at the back of the eye that is light-sensitive, taking light and converting it into signals that are sent to the brain via the optic nerve
Macula: a small area in the center of the retina that helps us see fine detail
Optic nerve: located in the back of the eye, this nerve transmits electrical signals from the retina to the brain
Vitreous: a transparent gel that fills the interior of the eye, helping it keep its shape
_____________ occurs when a gland in or on the eyelid becomes plugged or blocked.
A stye (also spelled "sty") occurs when a gland in or on the eyelid becomes plugged or blocked. It appears as a pimple or abscess on or in the eyelid. When a stye occurs on the inside of the eyelid, it is called a hordeolum. A chalazion is a type of stye that occurs when an oil-producing gland in the eyelid becomes clogged.
Which term describes a group of symptoms that occur after extended use of the eyes?
Eye strain, or eye fatigue, describes a group of symptoms that occur after extended use of the eyes. Causes of eye strain include staring for an extended time at digital devices (computers, cell phones, or video games), reading, driving, or activities in low light. Symptoms of eye strain include irritated eyes, headaches, blurred vision, increased sensitivity to light, or eye dryness. Eye strain is usually not serious, but if it occurs frequently it may be a sign of an underlying medical condition. See your doctor if your eye strain does not go away after you remove the eye stressors.
What is the name for the tiny spots that appear in your field of vision?
The tiny spots that appear in your field of vision are called floaters. They are usually most noticeable when you look at a bright background such as a sky, and they seem to move as you move your eyes. Floaters can appear as spots or straight or curvy lines or strings, or even as small blobs. You may see just one floater, or many. Floaters are caused when collagen fibers break away from the vitreous part of the eye and accumulate.
Most floaters are annoying, but benign and many will improve or disappear over time. In some cases, floaters can be a sign of a serious eye condition such as retinal detachment, retinal tear, eye tumors, or bleeding in the eye.
See an eye doctor (ophthalmologist) if you have eye pain, floaters that worsen over time or change suddenly, if you experience any other disturbances in your vision such as flashes of light, or if your floaters develop after surgery or trauma to the eye.
Sensitivity to light is the inability to tolerate light, medically known as phototropism.
Photophobia is a sensitivity to light that causes a person to have discomfort or even pain in bright light. For some, even normal indoor lighting can cause a sensitivity reaction of squinting or a need to close the eyes. People with light-colored eyes are more likely to have this problem. If you have sensitivity to light accompanied by pain, headache, nausea or vomiting, or blurred vision, see your doctor as you may have an underlying medical condition that needs to be addressed.
Worldwide, what is the leading cause of irreversible blindness?
The leading cause of irreversible blindness worldwide is glaucoma. This disease damages the optic nerve, which can lead to blindness. Everyone over 40 should be tested for glaucoma because if it is detected early, treatment can often prevent or slow vision loss.
Clouding of the lens of the eye, this disease or condition is usually a result of aging.
A cataract is the clouding of the lens in the eye. The most common cause of cataracts is the aging process. Cataracts can usually be treated with surgery.
This visual impairment occurs in almost everyone.
Astigmatism is a common visual condition that causes blurred vision. It is caused by an irregularly shaped cornea or a curvature of the lens inside the eye. It often accompanies nearsightedness (myopia) or farsightedness (presbyopia). Minor astigmatism usually does not cause visual problems, but more severe astigmatism can result in symptoms including distorted or blurred vision, headaches, or eye discomfort. Eyeglasses or contact lenses can be prescribed to treat this condition and help you see clearly. Laser eye surgery may also treat some forms of astigmatism by reshaping the cornea.
The terms "ectropion" and "entropion" describe eyelids which…
Ectropion is a condition where the eyelids turn outward. This can leave the eye exposed and cause dryness and irritation. Entropion is when the eyelids turn inward and rub against the eye causing irritation, redness, and eye sensitivity. Both conditions are often caused by weakening of muscles due to aging, and both can be treated with surgery to restore the eyelids to their normal positions.
If you have _____________, your eyes are unable to produce a sufficient amount of tears.
Dry eye syndrome (DES) (also called keratoconjunctivitis sicca [KCS], dry eye disease, and dysfunctional tear syndrome) develops when the eyes are unable to produce a sufficient amount of tears to keep the eyes lubricated. Women are more likely to develop this condition than men, and it becomes more common as we age. Symptoms include irritated or burning eyes, a feeling of something in the eye, and blurred vision. Artificial tears can help relieve symptoms in many cases. There are also procedures that can block tear ducts to keep more tears in the eye, or use of prescription eye drops that help increase tear production.
If one of your pupils (the dark center of the eye) is larger than the other, you have __________________.
Adie Syndrome (also called tonic pupil or Adie's tonic pupil) is a neurological disorder that is characterized by one pupil that is larger than the other (dilated) that reacts (constricts) slowly in the presence of bright light. The condition is usually harmless and often does not require treatment. In some cases, prescription eye drops or glasses may help restore impaired vision. If a dilated pupil is associated with a recent history of head trauma, headache, weakness in an arm or leg, or slurred speech, seek medical care immediately.
Images provided by:
MedicineNet. Picture of Eye Anatomy Detail.
MedicineNet. Sty (Stye).
UpToDate. Eyelid lesions.
MedicineNet. Eye Strain.
MedicineNet. Six Common Eye Complaints.
UpToDate. Patient information: Glaucoma (The Basics).
MedicineNet. Image Gallery: Picture of Astigmatism.
American Optometric Association. Astigmatism.
WebMD. Quiz: Drooping Eyelids – Description.
American Society of Ophthalmic Plastic and Reconstructive Surgery. Ectropion.
American Society of Ophthalmic Plastic and Reconstructive Surgery. Entropion - Eyelids That Turn In.
MedicineNet. Dry Eye Syndrome.
UpToDate. Dry Eyes.
American Optometric Association. Dry Eye.
WebMD. Adie Syndrome.
UpToDate. Tonic Pupil.
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