A cataract is the clouding of the natural lens inside the eye. As the natural lens of the eye becomes cloudy, it does not allow light to pass through it as well as it did when it was transparent. The natural lens is made of a strong, transparent outer covering or capsule filled with a clear gel material. When the gel starts to become cloudy, the incoming light rays are distorted or blocked before reaching the retina at the back of the eye. As the cataract develops, it becomes harder for a person to see.
Cataracts can progress with time. The more dense the cataracts become the more severe symptoms are.
They are usually white but can be tinted yellow or brown. This can affect the way colours appear. When cataracts first appear the changes in the lens are so mild they are called "trace cataracts". As these changes progress they will be called "mild to moderate" and once the cloudiness becomes very pronounced they are called "mature or ripe cataracts".
Symptoms first appear as looking through a frosty or dirty window. As this frost or dirt increases, it becomes more difficult to see things clearly and eventually as the cataract progresses light becomes blocked out.
Cataracts vary in the way they develop but usually progress at a slow pace therefore symptoms will progress slowly.
If your vision is blurry and you suspect that you may have a cataract you need to go and see your eye care professional and have a thorough eye exam done. A thorough eye exam will determine if a cataract is present and will give the eye care professional a look at the entire health of your eye to see if any other eye conditions are present and to also give your doctor a clear understanding of what your outcome will be after having cataract surgery. Some patients who have eye diseases, which affect the retina, may not have a good result from having cataract surgery. This must be explained to the patient prior to surgery so he or she will have a clear understanding of their outcome.
During the examination, Dr. Deans will discuss with you what difficulties you are having with your vision and how this is affecting your daily life. We will check your vision using an eye chart. Your eyes will be dilated using drops to enlarge the pupils, this allows the doctor to see more of the lens and retina and look for other eye conditions.
Once you are diagnosed with a cataract, Dr. Deans will discuss whether you should undergo surgery or wait until your vision interferes with your daily activities. Most patients have cataract surgery once they can no longer see well enough to drive, however, if you do not drive and you can still function normally you do not need to undergo surgery. In the past, doctors used to wait until the cataract was "ripe or mature" before removing it and patient's were left to live with very limited vision prior to removal. Thanks to dramatic advances in cataract surgery, it is no longer necessary to wait for the cataract to mature. Once your vision interferes with your daily activities, you can have them removed.
Measuring The Eye
The Zeiss IOL Master was approved by the United States Food and Drug Administration in March of 2000. A non-contact optical device that measures the distance from the corneal vertex to the retinal pigment epithelium by partial coherence interferometry, the IOL Master is consistently accurate to within ±0.02 mm or better. The IOL Master is the first such device to be widely used in clinical ophthalmology. Calibrated against the ultra-high resolution 40-MHz Grieshaber Biometric System, an internal algorithm approximates the distance to the vitreoretinal interface, for the equivalent of an immersion A-scan ultrasonic axial length. Considering the fact that axial length measurements by A-scan ultrasonography (using a standard 10-MHz transducer) have a typical resolution of 0.10 mm to 0.12 mm, axial length measurements by the IOL Master represent a fivefold increase in accuracy.