A cataract is a clouding of the normally clear and transparent lens of the eye which is located behind the pupil. When the lens becomes cloudy from age, injury or a birth defect, less light reaches the interior of the eye and vision gradually fails. Symptoms of cataracts range from a barely noticeable loss of vision to virtual blindness. The first symptom may be difficulty in performing routine tasks. Fuzzy or blurred vision, frequent changes in glasses, double vision in one eye, problems reading, decreased color perception and poor night vision are common symptoms. Night driving in particular may be a problem. Vision may fluctuate from normal to almost complete blindness under bright light or glare conditions. The image below is a slit-lamp photograph of an advanced cataract.
In the early stages of cataract development, a change in glasses may be all that is necessary to improve vision. The usual test for visual acuity, the Snellen letter eye chart, may not reflect the true extent of your visual loss. Other tests which measure glare sensitivity, contrast sensitivity, night vision, color vision and side or central vision may be useful. Some of these tests may help predict the degree of visual recovery after cataract surgery. In addition, A-Scan Biometry is performed to determine the power of the intraocular lens (IOL) needed to replace your cloudy natural lens, which has become the cataract. If you have previously undergone PRK or LASIK Surgery measurements of the front and back surfaces of the cornea using the Pentacam are entered into formulae and nomograms to determine the correct power of the IOL to be implanted. Surgery is the only way to remove a cataract. When cataracts cause enough loss of sight to interfere with your work or lifestyle, it is time to remove them. Most patients choose to have an intraocular lens that attempts to achieve a post-operative vision for either distance or near. However, another option is the Tecnis Multifocal IOL (video here) that offers multifocal vision. Although many patients achieve this visual goal, the architecture of this lens causes halos that may require many months for acclimation. Occasionally, this side effect is sufficiently irritating that the lens is removed and replaced with a standard implant.
You and Dr. Rubman will decide together when surgery is desirable. The ability to safely operate a motor vehicle is a consideration for some people. Surgery is not necessary just because a cataract is present. Symptoms may be mild and well tolerated. On the other hand, there is seldom a need to delay surgery when vision loss from a cataract interferes with your daily activities. It is a misconception that cataracts need to be ripe before removing them. Surgery can be performed whenever visual needs require it. Cataract surgery is a highly successful procedure. Useful vision is restored in over 90% of the cases. There may be other reasons for visual loss in addition to the cataract, particularly problems involving the retina or optic nerve. If these conditions are severe, removal of the cataract may not result in any visual improvement.
There are two circumstances in which removal of a cataract should be considered even though improvement in vision may not be expected. A cataract may be so advanced that diagnosis or treatment of other disease cannot be performed properly. In this situation it may be best to remove the cataract to allow the interior of the eye to be adequately examined. It is also possible for a cataract to become so advanced that the cataract itself causes other eye disease, particularly inflammation or glaucoma. These rare situations are the only ones in which cataract removal may be considered an emergency. Cataracts are removed using the small incision technique of Phacoemulsification, which has evolved over the past 25 years and represents the gold-standard for cataract extraction. The Cataract Video Consent is located here . The quiz associated with the video can be found here. The Surgical Consent Form can be found here. As an adjunct to standard Phacoemulsification, Laser Assisted Cataract Surgery has become available to facilitate and sometimes dramatically improve upon the traditional technique (click here for a discussion of its advantages).
The first stage of Phacoemulsification, after initial incisions have been made in the anesthetized eye, is the Capsulorhexis. The cataract is enveloped in a capsular bag. The anterior aspect of this capsular bag is opened by a continuous tearing maneuver as shown below:
When the anterior capsule has been opened and removed, access to the cataract is now possible. The Phacoemulsification instrument is then introduced into the eye. Using a combination of ultrasonic energy waves and mechanical fracture, the cataract is broken into small fragments and aspirated from the eye. The illustration below shows the cataract in the process of being divided into sections.
Each section is then emulsified by high energy sonic waves and aspirated from the eye.
After the cataract has been removed, the empty capsular bag remains.
A folded Intraocular Lens having the appropriate dioptric power, is then implanted into the capsular bag, restoring vision to the patient.