A cataract is a clouding or opacification of the natural lens of the eye. Cataract is often part of the aging process or may be associated with trauma, diabetes, or use of steroid medications. Early or minimal cataract may not require treatment other than observation and any necessary change in eyeglass prescription. When poor vision due to cataract affects the quality of life, cataract surgery is recommended.
Cataract Surgical Procedure
Cataract surgery is performed as an outpatient procedure in an ambulatory surgical center or in a hospital operating room. The surgical eye is dilated with eye drops or by placement of a small drop-soaked sponge. In most cases, eye drops alone will be used to numb the eye. Local anesthesia, supplemented with intravenous sedation, may also be used. An anesthesiologist or anesthetist is present during the surgery to monitor vital signs and administer any medications needed to make the patient comfortable. A feeling of pressure may be noted, but there is no pain during the procedure.
A microscope is positioned and an eyelid holder is placed between the eyelids to prevent blinking during the surgical procedure. Two small incisions (measuring 1mm to 3mm, or 1/24 inch to 1/8 inch) are made on the edge of the cornea. The central front portion of the lens capsule is removed and saline solution is used to separate the cataract layers. A probe is inserted, which bathes the eye with cooling fluid, applies high frequency ultrasound energy to emulsify (liquefy) the cataract, and provides gentle suction to remove the emulsified particles. This process is known as phacoemulsification.
An intra-ocular lens (IOL) is then folded, inserted through one of the incisions, and unfolded into its permanent position. The normal pressure of the eye seals the small incisions, which usually require no stitches. Because of the small size and shape of the incisions, healing and stabilization occur very quickly. A mild foreign-body sensation may be perceived when the anesthetic drops wear off. This may last for several days.
Many different types of intraocular lenses (‘implants’ or ‘IOL’s) are available now, with new implant types in development. The choice of implant depends on factors such as astigmatism, pupil size, anatomical considerations, presence of macular degeneration, and the patient’s desires. Standard, or monofocal, implants are usually used for good distance vision and reading glasses are needed (see Deluxe Implants below). Some of the monofocal implants used more commonly by Dr. Fuerst are:
- Alcon Acrysof™ and Alcon Acrysof™ natural – These are foldable acrylic lenses. The Alcon Acrysof™ natural blocks certain light wavelengths which may contribute to causing or worsening macular degeneration.
- Alcon Acrysof™ Toric – This foldable acrylic lens can correct certain amounts of astigmatism.
The choice of implant power is based on the patient’s individual desires. Traditionally, implant power is selected to create the best possible distance correction without needing spectacles. In this case, spectacles are needed primarily for near and intermediate tasks. Some patients opt instead for blended vision or monovision.
In blended vision, implant powers are selected for each eye to provide a range of functional vision. Near/intermediate or far/intermediate ranges can be planned, with spectacles needed for tasks outside of the achieved range. In monovision, one eye is corrected for distance and the other eye is corrected for near. This approach works best in patients who have used contact lenses to achieve monovision and are comfortable with this. With blended vision or monovision, spectacles may be necessary for some tasks such as prolonged reading or driving.
While precise measurements to determine implant power are performed, planned results are not always achieved, usually due to anatomical variations of the eye. In most cases where the patient is not satisfied, the implant can be exchanged or a second implant called a ‘piggyback lens’ can be placed to attain the desired visual result. Refractive surgery, such as LASIK or PRK, may also be used to fine-tune the result.
Cataract Surgery and Deluxe Implants
Cataract surgery, removal of the lens of the eye and replacement with an artificial intraocular lens implant (IOL), has been performed for over 50 years. The results of this outpatient surgical procedure are generally excellent. In fact, almost 3 million cataract surgical procedures are done in the U.S. each year. Until recently, however, spectacles were almost always required after cataract surgery for many – even most – tasks. With the introduction of deluxe IOLs that allow multiple focal points, and techniques which reliably correct astigmatism, it is now possible to achieve good vision for most tasks without the necessity of spectacles.
Presbyopia is the condition which results when the natural lens of the eye loses its flexibility. It is a normal aging process which frequently becomes noticeable around the age of 40, when near vision tasks become difficult, especially in dim light. Reading glasses, bifocal or progressive glasses, or monovision contact lenses are the traditional solutions.
Cataract surgery with the use of a presbyopia-correcting IOL is now possible for patients with visually significant cataracts. In the absence of cataract, PRELEX, or PREsbyopia Lens Exchange, is performed just like cataract surgery. PRELEX with a presbyopia-correcting IOL is a solution for presbyopes who wish to minimize their dependence on glasses but do not have visually significant cataracts.
Two types of IOLs are now available which focus objects at multiple distances – multifocal IOLs and accommodating IOLs. Multifocal IOLs work by presenting two or more focal points simultaneously. The eye and brain subconsciously concentrate on the desired image and ignore the undesired image. There is a period of adaptation to the IOL which can take several months, during which some glare and haloes are seen, especially at night. Most people adapt very well to these lenses. The FDA-approved multifocal lenses are the ReZoom, manufactured by AMO, and the ReSTOR, manufactured by Alcon.
The other type of IOL is the Crystalens, an accommodating IOL. This IOL allows focusing by moving a small amount in the eye to bring objects at different distances into focus. This IOL generally provides excellent distance and intermediate vision, with spectacles needed for reading fine print. There is a period of adaptation with improvement in the range of vision over several months.
Which of the available presbyopia IOLs to use is decided on based on a number of factors. The most important factor is the desired outcome, but pupil size, history of wearing glasses or contact lenses, lifestyle issues, etc. play a roll. The best results are often achieved by placing the same type of IOL in both eyes, but sometimes 2 different IOLs are used.
Presbyopia IOLs work well and provide more satisfied patients than monofocal IOLs in the vast majority of patients. Despite careful measurements and techniques, sometimes the desired outcome is not achieved and additional procedures may be required. These additional procedures include replacing the IOL with a different power, replacing the IOL with a different IOL style, and refractive surgery to fine-tune the focus.
Presbyopia-Correcting Intraocular Lenses
Alcon ReSTOR – This technologically advanced multifocal IOL combines refraction (light-bending optics), diffraction (wavefront optics) and apodization (image quality improvement) to provide a quality range of vision. A high level of spectacle freedom is achieved with the ReSTOR lens and patient satisfaction is very high.
AMO Technis Multifocal – This third-generation multifocal refractive IOL provides a full range of vision in varying light conditions. The Technis Multifocal IOL has a diffractive aspheric design. The Technis Multifocal lens provides spectacle independence in almost 90% of patients. Visual disturbances – nighttime glare and halos – may be noted initially, but usually become less noticeable over time.
Bausch & Lomb Crystalens – The Crystalens is the only accommodating IOL available, using the eye’s natural focusing muscles to provide a range of vision. The majority of Crystalens patients achieve freedom from spectacles for distance and intermediate tasks. Near (reading) vision sometimes requires reading glasses. Over time, the eye muscle focusing ability can improve, with a corresponding improvement in near visual function.
Why Dr. Fuerst?
Dr. Fuerst has extensive experience performing cataract and refractive surgery. He is certified to use all of the currently FDA-approved presbyopic IOLs, so he can use the lens that makes the most sense for each individual patient. He is also experienced in the performance of astigmatic corneal surgery.
Dr. Fuerst utilizes the latest diagnostic and treatment technology to optimize surgical outcomes. This includes MARCO computerized refraction stations, the Zeiss-Humphrey IOLMaster non-contact biometer, the ALCON Ocuscan Immersion biometer, the Zeiss-Humphrey corneal topographer, the ALCON Infiniti Cataract system, and the Holladay IOL consultant.
Costs for Deluxe (Presbyopia-correcting) Implants
Medicare and private insurance companies cover cataract surgery. An additional charge is made for a deluxe IOL. This charge includes the cost of the lens itself and the additional testing and follow-up which this new technology requires. It also includes most costs associated with additional procedures required to optimize the results of the surgery (replacement of the lens, astigmatism adjustments, LASIK touch-ups) if required.
If there is pre-existing astigmatism, there is an option to have this corrected surgically. The purpose of correcting the astigmatism surgically is to decrease the need for glasses or contact lenses postoperatively. In many cases, an IOL can correct the astigmatism. In other cases, micro-incisions can be placed in the cornea to reduce astigmatism. These incisions are called limbal relaxing incisions (LRIs). If the astigmatism is not corrected at the time of cataract surgery, LRIs may be performed in the office.
Limbal Relaxing Incisions to correct astigmatism
Eye drops are used for several weeks to help prevent infection and control inflammation. Post-operative examinations are usually scheduled within 1 day, at 1 week, and at 1 month. It is important not to rub or bump the eye and to use protective eyewear when engaged in any activity which may cause eye injury. Swimming or diving underwater should be avoided for at least one week.
Most patients return to their normal routine immediately. While everyone heals at a different rate, many patients note significant improvement in their vision right away. Depending on the rate of healing and visual needs, corrective lenses may be prescribed from between one and six weeks after surgery.
Cataract surgery is highly successful. Significant, sight-threatening complications are rare. These include intraocular infection (endophthalmitis), retinal detachment, corneal edema (swelling), retinal edema (swelling), and hemorrhage. Additional surgery may be necessary to correct implant power miscalculations, reposition a displaced implant, or remove retained cataract particles. Symptoms of glare, haloes, double vision, and ghost images may occur. Abnormalities of pupil size, shape, or function may rarely result from cataract surgery.