What Is A Cataract?
Our clinic's ophthalmologists, Dr. Ashenhurst and Dr. Hill, can assist with different medical eyelid surgeries in Calgary. Medical eyelid surgery can help with eye conditions like ptosis and blepharoplasty. Depending on the surgery and the severity of your condition, Alberta Health may cover the surgery.
Your eye's lens functions much like the lens in a camera and focuses incoming light rays onto the retina. The lens is contained in a very thin membranous bag called the capsule. The capsule is held in place by tiny filaments called the zonules. The retina acts like the film in a camera. It gathers the visual information and sends it to the brain. The lens must be clear and have the correct power to focus images on the retina properly.
Common symptoms of a cataract:
- Painless Blurring Of Vision
- Glare & Light Sensitivity
- Poor Night Vision, Especially When Driving
- Doubling Of Vision In One Eye
- Fading Or Yellowing Of Colours
- Needing Brighter Light To Read
A cataract is not:
- A Film Over The Eye
- Spread From One Eye To The Other
- Caused By Overusing The Eyes
- A Cause Of Irreversible Blindness
What Causes Cataracts?
Cataract formation is part of the normal aging process. The formation of cataracts may be accelerated by ultraviolet light exposure, smoking, laser eye surgery, diabetes and steroid-containing medications. Sometimes infants are born with cataracts called "congenital cataracts." Trauma to the eye can also cause a cataract in a previously normal eye. There is no current medical therapy such as eye drops or diets available to prevent or treat cataracts. Fortunately, cataract surgery has a high success rate.
When Should Cataracts Be Removed?
The decision to remove cataracts is made when vision blurring becomes significantly symptomatic and when surgery would be expected to be the best option for improving the vision.
Based on your symptoms, you and your ophthalmologist should decide together when surgery is appropriate. It is not true that cataracts need to be "ripe" before they can be removed. Cataract surgery can be performed when your visual needs require it. Sometimes it is medically necessary to remove cataracts for the overall health of your eyes. You must decide if you can see well enough to do your job, enjoy hobbies and activities, drive safely*, and read or watch TV in comfort.
*Driving standards exist as to the MINIMUM visual acuity required (20/40 in one eye), but you may not feel comfortable driving even if you have this vision.
How Is Cataract Surgery Performed?
Cataract surgery is usually done as an outpatient procedure at a surgical clinic under topical anesthetic (drops). You must be able to co-operate fully with your surgeon during the procedure if the topical anesthetic is used. Please request a local needle anesthetic if you feel you will be unable to hold your eye steady, relax your eyelids open or are very nervous about your eyes and the procedure.
Dilating eye drops are placed in the eye by a technician approximately a half-hour before the surgery. Using a microscope for magnification, a small hole is made in the eye, and an ultrasound probe is used to break up the cataract into tiny fragments. These fragments are then vacuumed out of the eye leaving behind the thin clear lens capsule. An artificial intraocular lens implant (IOL) is then placed in the c capsule.
A refractive error means that the eye does not focus light sharply on the retina, and the image that is seen is blurred. Refractive errors include myopia "near-sighted," hyperopia "far-sighted," and astigmatism (Warping of the corneal surface). We treat refractive errors with either glasses, contact lenses, corneal or implant surgery.
There are two ways to measure eyes for IOL power, ultrasound (A-scan) and laser (IOL Master). We sometimes need to perform and compare both of these methods for the most accurate results possible. The accuracy of both tests is affected by patient co-operation. Eye measurements will take about an hour. Your co-operation is essential to obtain accurate measurements. The IOL Master uses advanced laser technology to precisely measure the eye before cataract surgery.
Previous refractive surgery such as Lasik, RK or PRK can seriously affect the measurements for implants. Please let us know if you have ever had this type of refractive surgery.
You cannot wear contact lenses for testing. If you use hard/gas permeable lenses, these need to be removed for one week before testing to gain accurate readings. Soft lenses need to be removed 24 hours prior.
How Do We Select Lens Implants (IOLS)?
These are designed to correct vision at ONE distance. You can correct simple myopia and hyperopia with standard IOL's. Using present technology, we can reliably achieve this goal within one diopter 95% of the time.
Usually, the focus for distance vision is chosen, and reading glasses are worn when needed. Sometimes focus for near is chosen, and distance glasses are worn. The lenses covered by Alberta Health are high-quality injectable lenses. These lenses do not correct all post-operative refractive concerns.
Premium Lens Calculations
Premium IOL's offer more post-operative refractive options, as outlined below. The costs of these lenses vary according to the manufacturer and clinic providing the implant. Alberta Health Care funds the standard high-quality foldable IOL cost and will credit this amount to you if you select a premium IOL (we have already subtracted this amount from the prices). Unfortunately for non-Albertan's, some other provinces do not even cover the cost of a foldable IOL and patients are required to pay for these. There is no GST for IOL implants.
With all upgraded lenses, there are extra charges involved above the cost of the lenses. These charges cover pre-operative patient counselling, corneal mapping, corneal vector assessment, administration fees, online calculations, pre-operative markings, and intra-operative adjustments, as well as post-operative presbyopia management.
Corneal astigmatism is a condition where the cornea is warped, causing blurring of vision. Standard IOL's do not correct corneal astigmatism. Toric™ IOL's may be implanted at the time of routine cataract surgery instead of the standard IOL. Presently Alberta Health Care does not cover the cost of this lens and the additional assessment. You will still require simple reading glasses.
Toric™ lenses are designed to reduce astigmatism significantly BUT may not ELIMINATE all astigmatism. You will not benefit from a Toric™ lens if you do not have astigmatism. If you have a scarred or thinned cornea, the Toric™ lens may not significantly he+- lp your vision.
Alcon® PanOptix ™ Trifocal Lens
The Alcon® PanOptix ™ is a new Trifocal lens, providing correction for near (20cm), intermediate (40cm), and distance (100cm+). It was designed to create higher clarity of correction at functional distances without glasses. E.g. Looking at your phone, reading a book, working on the computer, or watching TV.
However, we can make no guarantee, and you may still require reading glasses for fine print. We find this lens is clearer for near vision, such as using a cell phone. There can be some halos around lights at night, specifically when driving. This can take around six months to settle but will never completely go away.
This lens also has a Toric counterpart to correct astigmatism.
Bausch + Lomb Finevision ™ Trifocal Lens
The Bausch + Lomb is another trifocal lens correcting for distance, intermediate, and near vision. It features a patented innovative trifocal structure designed to improve performance for intermediate vision.
We find this lens is better suited for the patient who uses computers regularly. Some halos around lights can take a few months to settle down, but these will never completely go away. You may need reading glasses for fine print even after surgery.
Risks Of Cataract Surgery
As with any surgery, there are risks associated with cataract surgery. Fortunately, these are rare. The least common is the loss of the eye. If you have concerns, feel free to contact your ophthalmologist.
Certain medications that reduce bladder neck spasm and help urination can have serious effects on the eye during cataract surgery. The most frequent offender is FLOMAX™. This medication causes poor pupil dilation and a floppy iris during surgery that can interfere with the surgeon's ability to remove the cataract and significantly increase the likelihood of intraoperative complications. Please let us know if you are currently on this type of medication or have EVER taken it. You must take certain special precautions before and during the surgery.
Rupture of the delicate capsule can occur in some eyes. This can result in the need for a second surgery and may make it impossible to implant the desired IOL.
After surgery, infection in the eye can be the most serious complication and can result in total blindness and eye loss. (0.1% risk) Symptoms include pain and increasingly blurry vision. The most common time to develop an infection is between two and seven days after surgery. Infections are treatable in most cases but MUST be brought to our attention RIGHT AWAY for the best possible outcome.
Despite our best efforts, significant myopia, hyperopia or astigmatism may exist following cataract surgery. This may be corrected with glasses, contact lenses, and refractive surgery or may require an IOL exchange. Differences in the post-operative lens power between both eyes may be particularly difficult to tolerate even with glasses and may require IOL exchange. IOL exchange is a separate surgical procedure and carries with it significant risks.
Cataract surgery may cause temporary double vision (around 10% of people will get this). In less than 1% of cases, double vision will be permanent. It may then require prism glasses or muscle surgery to correct the double vision. Anesthesia with topical drops/gels rather than a needle is much less likely to cause double vision.
Corneal swelling and astigmatism can reduce vision after surgery. The swelling is usually temporary (lasting several days up to several weeks), but some are prone to prolonged or permanent swelling.
Ptosis (Droopy Eyelid)
The upper eyelid has a delicate tendon that may be stretched as a result of any eye surgery. Patients who have previously weakened this muscle by minor injury such as prolonged contact lens wear may be at increased risk. Post-operative ptosis will sometimes improve spontaneously but often requires an eyelid "tuck" procedure, which is performed under local anesthetic. Ptosis will occur in about 1% of patients.
One of the most common complications is scar tissue formation on the capsule behind the artificial lens. This is called a "secondary" cataract and is sometimes referred to erroneously as the cataract "growing back." A routine laser treatment called a "YAG Capsulotomy" quickly treats this capsule opacification. This laser treatment is painless, quick and required in about 25% of patients. It carries with it a small risk of eye pressure rise and retinal detachment.
It is not unusual for the eye's pressure to rise after surgery, resulting in some discomfort. This is usually temporary and may require medication on a short-term basis. Pressure problems are more frequent in patients with glaucoma or in patients who are prone to glaucoma.
Retinal detachment can be associated with cataract surgery and cause severe vision loss (1% risk). Retinal detachment symptoms are floating dots, flashing lights, and a curtain of vision loss approaching from the outside into the central vision. Retinal detachment should be treated as soon as possible.
Retinal swelling may reduce vision after cataract surgery (macular edema). This may require additional tests on the eye, eye drops, oral medications or rarely injections of medication into or around the eye.
Cataract surgery can help improve the quality of your vision and life. If you're wondering if it's time to pursue cataract surgery, having your family physician refer you to an ophthalmologist for eye tests is essential. If you have other questions about your upcoming cataract surgery, please contact our office.Contact Us