Basic Cataract Info

Cataracts and Cataract Surgery

Cataract symptoms

Your eye works a lot like a camera. Light rays focus through your lens on the retina, a layer of light sensitive cells at the back of the eye. Similar to film, the retina allows the image to be "seen" by the brain. But over time the lens can become cloudy and prevent light rays from passing clearly through the lens. This cloudy lens is called a cataract.

The typical symptom of cataract formation is a slow, progressive, and painless decrease in vision. Other changes include: blurring of vision; glare, particularly at night; frequent eyeglass prescription change; a decrease in color intensity; a yellowing of images; and in rare cases, double vision.

Ironically as the lens gets harder, farsighted or hyperopic people experience improved distance vision and are less dependent on glasses. However, nearsighted or myopic people become more nearsighted or myopic, causing distance vision to be worse. Some types of cataracts affect distance vision more than reading vision. Others affect reading vision more than distance vision.

Cataract

A cataract is a loss of transparency, or clouding, of the normally clear lens of the eye. As one ages, chemical changes occur in the lens that make it less transparent. The loss of transparency may be so mild vision is hardly affected or so severe that no shapes or movements are seen, only light and dark. When the lens gets cloudy enough to obstruct vision to any significant degree, it is called a cataract. Glasses or contact lenses cannot sharpen your vision if a cataract is present.

The most common cause of cataract is aging. Other causes include trauma, medications such as steroids, systemic diseases such as diabetes and prolonged exposure to ultraviolet light. Occasionally, babies are born with a cataract.

Reducing the amount of ultraviolet light exposure by wearing a wide-brim hat and sunglasses may reduce your risk for developing a cataract but once developed there is no cure except to have the cataract surgically removed. Outpatient surgical procedures can remove the cataract through either a small incision (phacoemulsification) or a large incision (extracapsular extraction). The time to have the surgical procedure is when your vision is bad enough that it interferes with your lifestyle.

Cataract surgery is a very successful operation. Millions of people have this procedure every year and 95% have a successful result. As with any surgical procedure, complications can occur during or after surgery and some are severe enough to limit vision. But in most cases, vision, as well as quality of life, improves.

Cataract Surgery

Phacoemulsification is the most common surgical method used in the USA to remove a cataract, which is a clouding of the eye's naturally clear lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the back of the eye. Having a cataract can be compared to looking at the world through a foggy window.

In phacoemulsification, an ultrasonic oscillating probe is inserted into the eye. The probe breaks up the center of the lens. The fragments are suctioned from the eye at the same time. A small incision that often does not require sutures to close can be used since the cataract is removed in tiny pieces. Most of the lens capsule is left behind and a foldable intraocular lens implant, or IOL, is placed permanently inside to help focus light onto the retina. Vision returns quickly and one can resume normal activities within a short period of time. For more information, please watch our cataract surgery channel.

Intraocular lens (IOL) implant choices

Although the intraocular lens was first implanted in 1949 by Sir Harold Ridley, intraocular lenses (IOLs) were not widely implanted during cataract surgery until the 1970s. Cataract surgery techniques and lens designs needed to evolve to permit their use such as foldable IOLs. The first IOLs were all monofocal or single focus lenses that could focus at a single focal point that could be near or far. Therefore, early IOLs were limited in their ability to be able to reduce the need for glasses and/or correct astigmatism.

In the mid-2000s, the development of newer IOL designs with astigmatism and presbyopia correction capabilities as well as the separate reimbursement of intraocular lenses (IOLs) from the global surgical fee spurred research and development into lens designs that could greatly reduce the need for glasses. Prior to this time, manufacturers had little incentive to create new IOL designs since they were not well reimbursed for the research and development costs associated with creating and approving new IOLs. Today, there are many IOL manufacturers and designs that we use, and some of the most popular choices are listed below:

The non-peer reviewed publication Review of Ophthalmology published a well-written article in January 2023 summarizing the state of IOL technology and the challenge of matching the right lens with the right patient. The main points in the article are that 1) there is no single perfect IOL but there is likely a best fit IOL that will better match with your hobbies and interests, 2) all IOLs have inherent design limitations and tradeoffs, 3) while value and cost are important considerations for IOL selection so is the preop state of the eye as well as future risks since the IOL choice is fixed.