Over the years, many advances have taken place in the field of cataract surgery. The newest techniques have become so refined that cataract surgery is now considered a refractive procedure, with the goal of not only removing the cataract, but also decreasing the patient’s dependency on glasses.
- Topical Anesthesia for Cataract Surgery
- Clear Corneal Incision
- Premium Lenses
- Limbal Relaxing Incision
- ORA Intraoperative Aberrometer
- The Callisto Eye
- Educational Videos
A cataract is a lens that has become cloudy. Many times, patients will say looking through a cataract is like looking through a dirty window. During cataract surgery, a small ultrasound device is used to remove this cloudy lens and a new, clear intraocular lens is inserted.
Prior to surgery, Dr. Yang will evaluate the cataract and the eye using a variety of different instruments. Here at the San Jose Eye Institute, we utilize the latest in technologies to ensure the best outcome possible. For example, although ultrasound can be used to measure the axial length of the eye to calculate which intraocular lens power to use, the most accurate refractive results are obtained when using optical biometry, such as the IOL Master 700.
Dr. Yang also exclusively use the Signature Phacoemulsification System with the new WHITESTAR™ Technology. It is this machine that creates the ultrasound which breaks up the cataract into tiny pieces. The WHITESTAR™ upgrade reduces the total amount of energy used during the cataract extraction, resulting in a much quicker recovery time for the patient.
Topical Anesthesia for Cataract Surgery
The technique of using only eye drops to anesthetize the eye is a significant advance in cataract surgery compared to using a needle. With a needle injection, a long needle is inserted just underneath the eyeball and the anesthetic is then injected behind the eye. There is a risk for bruising of the eyelids, bleeding around the eyeball, droopy eyelids and injury to the muscles and other tissues around the eye. Patients are also heavily sedated. With topical anesthesia, only eye drops are used to numb up the eye. There is an anesthesiologist to keep patients comfortable and relaxed, but there is no risk for bleeding and there is no chance that a needle could inadvertently penetrate the eye. Following cataract surgery, patients with a needle are required to have their eye patched until the next day, whereas those with topical anesthesia can go home without any eye patch. Dr. Yang routinely uses topical anesthesia in order to achieve these optimal results.
Clear Corneal Incision
There are many techniques used to enter the eye in order to remove the cataract. The size and location of the incision can affect the curvature of the cornea and potentially induce astigmatism. This can be minimized by having a smaller incision. Incisions in the sclera (the white part of the eye) are typically larger in length, whereas incisions in the clear part of the cornea tend to be very small. Dr. Yang typically uses a 2.4 mm incision in the cornea, resulting in an incision that does not require sutures to close.
Furthermore, unlike cutting in the sclera, there is no bleeding associated with making an incision in the cornea. As a result, without using a microscope, it is difficult to tell that surgery was even performed.
Premium Intraocular Lenses
Traditionally, a mono-focal lens is placed in the eye during cataract surgery. Following surgery with a mono-focal lens, the patient will typically need glasses to fine-tune the vision, allowing the patient to see far, intermediate and near. Lens technology has grown significantly, and today, there are many different lens options. Besides the standard mono-focal lens, there are now special Premium Lenses that offer unique features designed to help patients become less dependent on glasses.
Toric Lenses: Toric lenses are designed to eliminate or significantly decrease the amount of astigmatism, or warping of the cornea surface. The amount of astigmatism reduced is extremely accurate and stable. By using a toric lens, the vision without glasses is improved because the distortion from astigmatism is improved. Toric lenses can remove upwards of 4 diopters of astigmatism. Ask Dr. Yang about the Alcon AcrySof IQ Toric IOL and the Tecnis Toric IOL.
Multi-focal Lenses: Multi-focal lenses allow images at different distances to be seen in focus. Working distances can be broken down into far (driving, TV), intermediate (cell phones, computers), and near (reading). Multi-focal lenses can bring two working distances in focus: either far and intermediate, or far and near, depending on the patient’s desire. Multi-focal lenses include the ReSTOR Multifocal lens and the Tecnis Multifocal lens. The ReSTOR Multifocal also comes in a toric version to help patients who also have astigmatism.
Accommodating Lenses: Accommodating lenses dynamically change their shape inside the eye to allow patients to see far, intermediate and near. The Crystalens is the first accommodating lens approved by the FDA. In 2013, Trulign was introduced, which is essentially a combination of the Crystalens with a toric lens to correct for astigmatism as well.
Extended Range of Vision Lenses: Extended Range of Vision lenses are a new category of premium lenses that allow patients to see far, intermediate and near. In contrast to multi-focal lenses, which allow patients to see two distances in focus, these lenses allow patients to see a continuous range of distances in focus. The Symfony lens and the Vivity lens are the two lenses in this category. Both of them have versions that are combined with a toric lens called the Symfony Toric lens and the Vivity Toric lens. There are also the Eyhance and the Eyhance Toric lenses. They do not officially belong in this category, but they behave very similarly to the other lenses in this category.
Tri-focal Lenses: Multi-focal lenses are essentially bifocal lenses, allowing patients to see two different working distances. The latest generation of these lenses is the trifocal lenses, allowing patients to see all three key working distances: far, intermediate, and near. The PanOptix is the first and only lens in this category, and it was approved by the FDA in 2019. The PanOptix also comes in a toric version, so pre-existing astigmatism can also be corrected at the same time.
Light Adjustable Lenses: The Light Adjustable Lens is in a new category of premium lenses that can be fine-tuned weeks after cataract surgery is performed. Using ultraviolet light, the shape of the lens can be customized to match the prescription of the patient’s eye more closely. The lens can address any residual near-sightedness, far-sightedness or astigmatism. The lens also has a range of vision similar to the extended range of vision lenses, resulting in less dependency on reading glasses and bifocals.
Dr. Yang offers all of the above premium lenses, giving patients the greatest flexibility in customizing the lens choices that are best suited to the patients’ lifestyle and visual demands.
Limbal Relaxing Incision
This is a technique similar to astigmatic keratotomy which can be used to decrease the amount of corneal astigmatism. A corneal topography is used prior to cataract surgery to map the extent and location of the astigmatism. Based on this map an incision is made on the cornea to decrease the amount of astigmatism. The effect of the incision is dependent on the patient’s ability to heal, and so the effect is somewhat variable. Reducing the astigmatism at the time of the surgery will further reduce the patient’s dependence on glasses.
ORA Intraoperative Aberrometer
This latest technology is used at the time of cataract surgery to improve the refractive outcome following cataract surgery. Traditionally, the power of the new intraocular lens is determined prior to surgery by measuring the curvature of the corneal surface and length of the eye. Because of the presence of the cataract, certain assumptions also have to be made, and the desired lens power is calculated.
With ORA, some of these assumptions can be eliminated. At the time of surgery, after the cataract is removed, ORA can be used to measure the true refractive power of the eye. Real-time calculations are then made to determine the best-fit lens power.
ORA can be used for any type of intraocular lens, whether a standard mono-focal lens is chosen or a premium lens. The result is a truly customized lens power calculation for each individual patient, resulting in improved uncorrected vision.
Also, there are certain eye conditions that lead to difficult lens power calculations, and can benefit by the use of ORA, such as having cataract surgery after LASIK surgery. During your cataract consultation, ask Dr. Yang whether ORA would benefit you in your cataract surgery.
The CALLISTO Eye
This is computer-assisted technology that allows the operating microscope to project clinical information on to the eye, and track the eye dynamically during cataract surgery, eliminating errors introduced by eye movement and rotation. This system has many applications, but there are two clinical situations that are particularly useful:
1. For patients who have astigmatism, and wish to have it reduced during cataract surgery, knowing the axis of the astigmatism is critical. The CALLISTO Eye system will project an image of the astigmatism axis on to the eye during surgery. When the surgeon looks through the microscope, the superimposed axis will rotate to compensate if the eye rotates.
2. Certain intraocular lenses are more sensitive and require centration with the visual axis. Unfortunately, the center of the visual axis does not necessarily correlate with the center of the eye or pupil. Before surgery, when the pre-op measurements are taken, the patient can look at an image, and CALLISTO Eye can determine the true visual center. This center is seen in the microscope, superimposed on the eye, and the new intraocular lens can be confidently centered.
This technology requires a significant equipment upgrade at the surgery center as well as the surgeon’s office, and Dr. Yang is pleased to be one of the few in the Bay Area to be able to offer this technology to his patients.
Accommodating Intraocular Lenses
Crystalens / Trulign