For those individual who have developed a cataract which is interfering with their daily activities such as driving, reading or recreational activities, some exciting options have become available. Previously when a cataract was removed, the only objective was to reduce the haziness produced by the cataract. With the advent of the intraocular lens, various optical corrections could also be achieved. The first generation lens implant could successfully improve distance optical corrections, reducing patient’s distance prescription. Second generation lens implants were developed to reduce optical conditions such as astigmatism. While these lens choices were attractive in many ways, there remained a weakness which prevented patients from seeing at near as well as at a distance.
Presbyopia is a universal eye condition which begins to manifest itself in the early to mid forties. As the eye ages the internal structure known as the lens becomes more rigid. Prior to that time, the natural lens of the eye has the ability to flex and provide good vision at distance and near. Once the process of presbyopia begins, we lose the ability to focus on near material. This process is universal but appears to affect people differently based on their baseline distance vision. For example, an individual who is near sighted will still be able to see at close without glasses well into their forties and fifties because their natural vision is at near and does not require them to focus with their lens at near. These individuals will remove their glasses at near to read when they become presbyopic. Newer technology implants can correct for this optical flaw.
The tecnis multifocal implant is among the most technologically advanced implants available. (You can skip the next science lesson if you wish and still appreciate the benefits of the lens described in the next paragraph.) The science behind this lens technology is fascinating in many ways. Eye glasses, cameras, telescopes and almost all other optical devices you will use utilize a basic physical principle of light. These lens bend light as it passes through. This process is known as refraction and is due to light having the same nature as the waves in the ocean. By refracting and bending light a point of focus is created behind the lens. So if someone is near sighted their eye focuses light in front of the retina. The lens in glasses or contacts bends light and moves the focus to the retina so they can see. But light is far more complex than a wave in the ocean. Light can also behave as a particle. Using this second principle of light as a particle diffraction is achieved. This effectively can create a second focal point of light. The tecnis multifocal was the first approved lens to use both optical systems in one lens. So in effect the tecnis works like two lenses in one.
So what is the benefit? This is what is special about this new technology. People like to think of this lens as a bifocal and they fear that similar to a bifocal they may have to look down to see near or they may feel funny walking around. This is where the new technology is far superior to any bifocal. The implant acts like two separate lenses so there is not a lower or upper. Both distance correction and near correction work through out the lens. It allows patient outstanding distance vision and instantaneously you can also see near directly in front of you. This lens implant can correct for a patient’s nearsightedness, farsightedness and presbyopia. You do not have to tilt your head to see the computer screen or a person in front of you. You do not need to refocus or use the muscles of you eye to focus at near as the natural eye does, which sometimes causes headaches. The tecnis automatically focuses because the are two optical systems are working all the time. All you need to do look at something and the lens does the focusing. There is no dizzy feeling similar to what is created by bifocal because the distance correction and the near correction are present throughout the entire lens. There is no line or transition area that creates the dizzy feeling which even the best progressive creates.
The power of the tecnis for near is available at different strengths to provide you with the optimal vision your particular lifestyle. If you like to hold things very close and see very small things the strong power is effective but if the computer, iPad or telephone represents most of your near work the lower power option would suit you.The ability to see distance and near without glasses is an attractive option for those individuals tryingto avoid glass wear.