Cataract Surgery - Grendahl Eye Associates ~ LASIK, PRK, laser vision correction, eye care, hyperopia - farsightedness, myopia - nearsightedness, astigmatism and excimer laser information.

CATARACT SURGERY

THE NEWEST TECHNOLOGY

Now we will describe the specific surgery we use for most cataract and lens implant operations. It uses the most recent technology and surgical techniques to restore your vision at the time of cataract surgery.

This new procedure is called REFRACTIVE CATARACT SURGERY

The goal of this surgery is not merely to remove the cataract but to allow you to see distant objects without glasses. Although we cannot guarantee that you won't have to wear glasses to fine tune your distance vision, at the very least, you will be able to get around without relying on glasses. Wearing glasses for reading will be necessary though, unless a multifocal lens is used or one eye is set for distance vision and the other eye is set for near vision. The goal is to make you less dependent on glasses.

If you are nearsighted, farsighted or have astigmatism, our goal is to correct this at the time of surgery. We try to correct your nearsighted or farsighted eyes by choosing the appropriate power of the intraocular lens implant. We do this by accurately measuring the curvature of your cornea and the length of your eye.

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A keratometer and corneal topography computer is used to precisely measure your curvature of your cornea.

We have chosen the immersion technique to measure your cornea to retinal distance, which assures the most accurate axial length measurement. This information is combined in three separate highly sophisticated computer third generation formulas which provide the specific intraocular lens correction for your eye surgery as well as determining the style of the intraocular lens to be used.

The surgery itself involves inserting a phacoemulsifier probe through a very small 3 millimeter incision, about 1/8 to 1/4 of an inch, made on the sclera (or through the clear cornea). The probe vibrates at 40-50 thousand cycles per second and turns your cataract into liquid, which is then aspirated out through the probe. The small incision, made possible by this probe, is a marked advantage over the older 11-14 millimeter incision still used by many eye surgeons. All surgical wounds larger than 3.2 millimeters creep, that is the healed tissue moves over time. The smaller the incision the smaller the amount of wound creep. The smaller the wound creep the less tendency to cause astigmatism. The old, larger incision procedure can cause severe astigmatism in approximately 25 % of the cases.

The small 3 millimeter incision used for phacoemulsification can creep a very small amount over 2-4 years. From a practical standpoint, this is hardly perceivable by the person who has undergone surgery. This is why we have chosen to use the smallest possible incision procedure to remove your cataract and insert your intraocular lens. The cost of the phacoemulsifier is $40,000.

The final step in refractive cataract surgery is to shape your cornea to near perfect round so that any preexisting astigmatism is corrected. This is done with a special $18,000 device called a surgical keratometer. It attaches to the operating microscope (costing $40,000) and is used to monitor the roundness of the cornea.

We want to make the cornea shaped like the back surface of a soup spoon or basketball (spherical), not like the back surface of a teaspoon or football (astigmatism). The surgical keratometer, along with very small relaxing incisions, allows us to reshape the cornea. Corneal topography (costing $31,000) is used as an integral part in the surgical planning for placement of the astigmatic cuts in the cornea and for placement of the cataract incision.

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If you have no preexisting astigmatism, care is taken not to cause any significant astigmatism. If there is little or no astigmatism prior to the cataract surgery, we use a 3 millimeter incision called a self sealing scleral pocket or clear corneal incision and no suture at all, along with phacoemulsification and employing a soft foldable intraocular lens. This lens is folded up much like a taco and inserted through the 3 millimeter phaco incision and then unfolded inside the eye or the lens is placed inside a small tube and injected into the capsular bag. This incision is very, very small and rarely requires a stitch to close the incision.

The end result, after applying this new technology during your cataract surgery, results in 50 percent of the people seeing well the day after surgery, and 40 percent seeing well 6 to 10 days after surgery. The remaining 10 percent have a slow, gradual improvement in vision.

We have noticed a much earlier visual recovery compared to the old technology involving the cutting of the sutures 1 to 12 weeks after surgery. Sutures dissolve over 3 to 4 years. With the newer technique, we don't use sutures. After having cataract surgery you can resume all of your normal activity within the week of surgery.

We do not recommend that you wait until your cataracts are hard or hypermature before you have cataract surgery because the longer you wait the harder the cataracts become. When the cataract is hard it makes it more difficult to phacoemulsify. There is a greater risk of rupturing the posterior capsule and then we can't use the foldable posterior chamber lens, which is the most desirable. If the capsule is broken, we then have to use an anterior chamber lens or an oval lens. Sometimes we have to place this lens in the sulcus.

We have chosen to use these techniques and instruments to assure the best possible results from cataract surgery. It has been estimated in 1992 that only 1 percent of the cataract surgeons use these new techniques (astigmatic keratotomy) and not all day surgery facilities have this expensive and sophisticated equipment. Currently about 20-30% of ophthalmologist are attempting to correct only the larger amounts of astigmatism by using nomograms. The facility we use has this equipment on hand so you may obtain the best possible results that technology offers today.

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What is corneal topography?

Corneal topography is a special test (computer analysis) that gives us a full analysis of the curvature of the cornea. A series of concentric circles are projected onto the cornea and the reflex off the cornea is captured and analyzed by a computer. This is like a topographical map of a mountain with elevation contour lines that show a detailed map of the surface contours of the mountain. The contour lines of corneal topography are arranged in special color coded areas of the same curvature. Instead of being elevation lines or areas these are in diopteric powers with a given color representing a given curvature. The hot colors (red, orange, and yellow) represent steeper curvatures and cool colors (green, blue, and purple) represent flatter curvatures. This map is used to plan the exact placement of the scleral pocket or a clear corneal incision and astigmatic cuts in the cornea to correct astigmatism.

What is a nomogram for astigmatism correction?

This is simply a table that lists how long and how many corneal cuts are needed to correct a given amount of astigmatism. This table is constructed from previous astigmatic cuts placed in 100-400 cases and represents the average response of a cornea to astigmatic cuts. This results in a predictability of plus or minus 1.25 diopters of correction in 80 percent of cases. Using a nomogram to plan these cuts is not the most accurate way to plan this type of surgical correction of astigmatism. This is because not all corneas respond like the nomogram suggests due to individual characteristics of different corneas. This is why we don't use nomograms.

What is tonometric control?

The intraocular pressure in the patient's eye is set to their average normal preoperative intraocular pressure at the time of surgery. This is done to allow accurate measurement of the curvature of the cornea for the correction of astigmatism.

What is keratometric control?

This is the intraoperative measurement of corneal curvature done with a special keratometer that fits onto a surgical microscope. This measurement is done in real time several times during the course of correcting corneal astigmatism with cuts in the cornea.