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Cataracts

Cataracts are cloudy areas in the eye's lens causing blurred or hazy vision. Some cataracts stay small and don't change your eyesight a lot. Others become large and reduce vision.

PubMed Health Glossary
(Source: NIH - National Institute on Aging)

About Cataracts

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.

A cataract can occur in either or both eyes. It cannot spread from one eye to the other.

What is the lens?

The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye.

In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain.

The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred.

Are there other types of cataracts?

Yes. Although most cataracts are related to aging, there are other types of cataract:...Read more about Cataracts NIH - National Eye Institute

What works? Research summarized

Evidence reviews

Benefits and Harms of Femtosecond Laser Assisted Cataract Surgery: A Systematic Review [Internet]

The preferred method of removing cataracts in the developed world is phacoemulsification. Using this technique, ultrasonic energy softens the dense lens material of the cataract, which is then extracted from the eye with suction and irrigation. Current practice includes creating manual corneal incisions and anterior capsulotomies, followed by phacoemulsification. Recently these three manual procedures have been performed in an automated fashion with the use of the femtosecond laser (FSL). Several FSL systems have been approved by the FDA for use in the U.S. for some or all of these procedural steps in cataract surgery. FSL technology has been widely used in various refractive surgery applications in recent years. Studies have suggested decreased phacoemulsification energy use with FSL cataract surgery and have examined the potential advantages of more precise corneal incisions and capsulotomy formation.

System evaluation of curative effects of intraocular lens implantation for treating diabetic cataract

Bibliographic details: Xu J.  System evaluation of curative effects of intraocular lens implantation for treating diabetic cataract. Journal of Clinical Rehabilitative Tissue Engineering Research 2009; 13(25): 4969-4972

Using medications (antimetabolites) to avoid scarring after cataract surgery, which might cause failure of a previous glaucoma operation

Review question: We reviewed the evidence on the effect of using medications (antimetabolites) to avoid scarring after cataract surgery, which might cause failure of a previous glaucoma operation. We did not find any trials to include in this review.

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Summaries for consumers

Using medications (antimetabolites) to avoid scarring after cataract surgery, which might cause failure of a previous glaucoma operation

Review question: We reviewed the evidence on the effect of using medications (antimetabolites) to avoid scarring after cataract surgery, which might cause failure of a previous glaucoma operation. We did not find any trials to include in this review.

Topical anaesthesia using eye drops alone compared with a combination of eyedrops and anaesthesia within the eye for cataract surgery

There are many different options for anaesthesia during cataract surgery. Using anaesthetic eye drops (topical anaesthesia) has become an increasingly popular option in modern, rapid‐turnover day case cataract surgery as it is minimally invasive, cost effective, less prone to complications and provides for faster patient rehabilitation. Many surgeons who use topical anaesthesia supplement this with anaesthetic administered within the eye (intracameral) during the surgery. This review has found that the use of intracameral lidocaine as a supplement to topical anaesthesia significantly reduces intraoperative pain perception when compared to the use of topical anaesthesia alone. No significant difference was demonstrated between the groups receiving topical anaesthesia alone and topical eye drops combined with intracameral anaesthesia in terms of the need for supplemental anaesthesia, intraoperative adverse events or corneal toxicity. We conclude that the administration of intracameral anaesthetic during surgery is an effective and safe supplementation to topical anaesthesia.

Comparison of two forms of local anaesthesia for cataract surgery

Cataracts are the commonest cause of blindness, worldwide. A cataract is the clouding of the lens that causes loss of transparency of the eye. It is treated by removing the lens and replacing it with an artificial lens. Cataract surgery is usually performed under local anaesthetic, either peribulbar or retrobulbar anaesthesia. There is debate over whether the peribulbar approach provides more effective and safer anaesthesia for cataract surgery than retrobulbar block. Peribulbar anaesthesia is performed by injecting the anaesthetic drug in the orbit around the equator of the eye ball (globe). Retrobulbar anaesthesia is performed by injecting the anaesthetic drug in the orbit further back behind the eye ball, which is near the nerves that control eye movement and sensation.

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Terms to know

Accommodative Lens
An accommodative intraocular lens implant has only one focal point, but it acts as if it is a multifocal IOL. Its design allows the focusing muscles to move it back and forth.
Intraocular Lens (IOL)
Artificial implanted lenses.
Lens in the Eye
A clear disk that focuses light, as in a camera or microscope. In the eye, the lens is a clear, curved structure at the front of the eye behind the pupil. It focuses light rays that enter the eye through the pupil, making an image on the retina (light-sensitive layers of nerve tissue at the back of the eye).
Monofocal Lens
Monofocal intraocular lenses provide vision at one distance only: far, intermediate, or near.
Multifocal Lens
Multifocal intraocular lenses allow the patient to visualize objects at more than one distance.
Ophthalmologist
A doctor who specializes in diagnosing and treating eye problems, including injury and disease.
Retina
The light-sensitive tissue lining at the back of the eye. The retina converts light into electrical impulses that are sent to the brain through the optic nerve.

More about Cataracts

Photo of an adult

Also called: Cataractous

Other terms to know: See all 7
Accommodative Lens, Intraocular Lens (IOL), Lens in the Eye

Related articles:
How the Eye Works

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