Cataract Treatment Procedure

1) Measuring the Eye
2) Lens Implants
3) PCRI for Astigmatism
4) Phacoemulsification

1) Measuring The Eye
IOL Master: Proven technology for the best eye measurements
Before undergoing cataract surgery, it is necessary to measure the length and front curvature of the eye. This is necessary for two reasons:
1) In order to determine the type and power of lens implant to be placed in the eye, the goal being to choose the lens that will provide the best possible distance vision without glasses.
2) The measurements obtained allow the surgeon to plan the most successful procedure based on the anatomy of the eye. For example, a very short eye will require a slightly different approach than a very long eye.

In addition, preoperative eye measurements will determine whether there is any astigmatism, for those patients who wish to have it surgically corrected at the time of the cataract extraction (see PCRI for further information).

There are two types of technologies for measuring the eyes: the ultrasound-based method, and the newer, laser-based technology (IOL Master). The IOL Master uses a laser linked to a computer to scan and analyze the dimensions of the eye.

The advantages of the IOL Master are:
1- Greater precision. The more precise the measurements are before the surgery, the better the choice of lens implant power will be, and as a result the better the postoperative distance vision will be without glasses.
2- It gives information about the depth of the front part of the eye. This information is very valuable in creating a surgical plan.
3- Provides exact measurement of astigmatism. This allows the surgeon to plan the best surgical treatment for the astigmatism, if desired.
4- Selects the optimal lens style and power using computer analysis.
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2) Lens Implants
During cataract surgery, the cloudy lens, or cataract, is replaced by a man made lens implant. The eye is measured beforehand in order to determine the implant power required to provide the best distance vision. Placement of a monofocal lens implant is a routine part of the cataract procedure, and is covered by OHIP. Certain specialty lenses are also available. These include the following:

1) Array™ Multifocal Lens: This lens is designed to provide near and intermediate vision along with the distance vision. The goal of this lens is to significantly reduce dependence on glasses. Common side effects may include haloes around bright point sources of light or other light sensations.

2) Tecnis™ lens: This lens is designed to minimize distortion of light rays as they are focused on the back of the eye, thus improving a quality of vision known as contrast sensitivity. The improvement is most noticeable in low light conditions, for example during night driving. In one study, patients with the Tecnis™ lens driving at 90 miles/hour saw the red light from 45 feet further away than patients with the regular lens. The Tecnis™ lens is the only lens that has been approved by the FDA of the United States as having the ability to improve the quality of vision. For more information about the Tecnis™ lens and contrast sensitivity, please visit www.tecnisiol.com.

3) Restor™ lens: This lens has a bifocal design, providing both distance and near vision.

4) Tecnis™ Multifocal (coming soon): This lens provides all of the benefits of the Tecnis™ lens along with multifocal vision, to significantly reduce dependence on glasses.

Not all individuals will be candidates for specialty lenses. If a lens is an option for you, you will be given information about it at the time of your surgical consultation with Dr. Misra. It is important to remember that there is no medical reason to have any one of these lenses: they are technological advances that may be chosen based on each individual’s preferences and lifestyle. top



3) PCRI for Astigmatism Correction
What is astigmatism?
Astigmatism is an anatomic condition that some individuals are born with. It means that the clear windshield at the front of the eye, the cornea, is shaped more like a football than a soccer ball. As a result, light and visual images do not come to a focus at a single point, but rather at two or more points, causing the vision to be blurry and out of focus.

        An eye WITHOUT astigmatism                        An eye WITH astigmatism

What can be done about astigmatism and what are PCRIs?
Astigmatism can be compensated for with glasses and contact lenses. It can be significantly reduced and in some cases eliminated by peripheral corneal relaxing incisions (PCRIs) and laser vision correction. With PCRIs, incisions are placed along the steep part of the cornea to modify its shape and make it more spherical (right).

What are the benefits of having PCRIs placed?
Patients that undergo the PCRI procedure can expect increased clarity of vision even when not wearing glasses. In no case will PCRIs eliminate the need for reading glasses.

How does it feel to have the procedure done?
The PCRI procedure is a sophisticated one that is performed right at the time of cataract surgery. Having it done will not noticeably increase the length of time that is takes to complete the surgery and will not cause increased pain either during or after the surgery. At most, some patients notice a slightly gritty sensation in their eye as it heals after surgery. This is also the case for many patients having cataract surgery alone.

What if I don’t have the procedure done?
Patients that choose not to have the procedure done can still wear glasses to sharpen their vision. top



4) Phacoemulsification
Phacoemulsification is a surgical method used 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. Because it is the entire lens that becomes cloudy, the entire lens must be removed and exchanged when a visually significant cataract develops.
In phacoemulsification, an oscillating ultrasonic probe is inserted into the eye. The probe breaks up 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. The IOL is intended to remain in the eye for life.
                 
Intraocular Lens Implant (IOL)                        IOL in place in the eye

Eyedrops must be taken for 3 days before and 4 weeks after surgery. Vision returns quickly and one can resume normal activities within a short period of time. The main restriction after surgery is that the eye may not be rubbed. top