Understanding Cataract

A natural effect of aging

When talking about their vision, most people over the age of 45 "focus" on the loss of near vision. The eye's natural crystalline lens helps us focus on people and things at varying distances. Unfortunately, as we grow older this lens often stiffens and hardens, and without its youthful suppleness, it loses its ability to focus, creating vision problems. This condition — for most, a natural consequence of aging - is called presbyopia. What they may not realize is that this the inevitable progression of presbyopia weakens the ability of the lens to focus in the field of vision that begins at our fingertips – known as intermediate vision. And, until now, this field of vision that has become the most important for today's active Boomers was severely compromised. As we age, these changes occurring to the natural crystalline lens can lead to the development of cataracts. By age 65, a large percentage of us will develop a cataract, most often typified by cloudy/fuzzy vision. With a cataract you may have difficulty seeing in extremely bright light or low-lighted conditions.

How does the eye WORK?

When you see an object, the cornea acts as a clear window on the front of your eye, transmitting and focusing light into the eye. The cornea performs two thirds of the focusing. The lens in the eye performs the remaining third of the focusing by working in a similar way to a camera lens, focusing light rays onto the retina at the back of the eye. The retina then reads the light rays and sends the focused image the brain via the optic nerve to allow you to see.

When a cataract develops, the lens, which is normally transparent, becomes cloudy or opaque. The lens contains proteins and water which are clear in a healthy lens. As the cataract forms, the protein clusters together, resulting in the cloudiness or frosting of the lens. This results in dull, blurred vision which deteriorates over time.

What causes a cataract?

The most common cause of cataracts is due to the ageing process in later adult life, causing the lens to harden. Often cataracts develop in both eyes at the same time. Age-related cataracts called senile cataracts can occur in people aged 40 years and over. Less common causes of cataracts include congenital cataracts in babies born with cataracts, chronic diseases such as diabetes, and traumatic cataracts caused by injuries to the eye. What are the symptoms of a cataract? The symptoms of a cataract may include: Blurred, fuzzy or hazy vision Night vision affected by glare or halos Reduced vision in bright surroundings or sunlight Faded colour vision Frequent changes in eyeglass prescription

How does a cataract affect eyesight?

The cloudiness interferes with the way light passes through the lens to the back of the eye. This causes patients to have blurred vision, or possibly “see double”, colour vision may be affected, or patients may experience difficulty to see in bright light. These symptoms often develop gradually over months or years. As the cloudiness spreads across the lens, it becomes more difficult to see clearly.

Improving Your Vision

Developing a cataract doesn't mean a permanent loss of vision quality, or having to give up the things you love, because cataract surgery is a safe, effective way to improve your vision. Cataract surgery is the most commonly performed surgery in India, with well over 5 million Indians having the procedure every year. Performed almost exclusively on an outpatient basis, cataract surgery is microsurgery, whereby the natural lens is removed and replaced with what is called an intraocular lens (IOL). The procedure is highly successful and most people regain very good distance vision.

During cataract surgery, your Surgeon will replace your natural lens with an IOL. Today there are multiple types of IOLs, each delivering a different performance profile based on how the lens is designed. Here are the basics about the three main types of IOLs:

A. STANDARD MONOFOCAL – SINGLE FOCUS SIMULATION

A monofocal IOL is a fixed lens (it doesn’t move) that is designed to deliver improved vision at just one distance (usually far). Is generally implanted for distances vision. For intermediate or near vision glasses will be needed. This lens can be implanted so one eye is for distance vision and the other eye is set for near (mono-vision). The potential drawback is that after surgery, you will probably need to wear glasses for near vision, even if you didn’t wear glasses before surgery.

B. MULTIFOCAL – BIFOCAL SIMULATION

A multifocal lens uses multiple visual zones that are built into the lens itself to provide vision at various distances. It’s almost like the rings of a target, with some rings being dedicated to distance vision, while others are used for near vision, similar to having a bifocal or trifocal lens inside the eye. Some patients have difficulty adjusting to seeing this way. Additionally, intermediate vision (subject’s at arm’s length) can be compromised because the technology is designed mainly for near and distance vision, at the exclusion of intermediate vision.

C. ACCOMODATING – NATURAL (EYE) SIMULATION

As the name implies, an accommodating lens “flexes” or “accommodates” to focus on subjects at various distances, delivering a continuous range of vision – near, intermediate and far. The focusing muscle in the eye moves the Lens forward (from the resting position or distance vision) which enables the eye to automatically focus vision and does not split light rays! Crystalens® is the one and only FDA-approved accommodating lens now available in India. More than twice the number of patients implanted with the crystalens could see at all distances compared to a standard IOL.

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