Last year Tyler Trafford noticed he was having trouble reading. The Calgary writer thought he just needed stronger glasses. When he went to his optometrist, he was in for a surprise.

“[He] told me I had rapidly growing cataracts – rapidly,” recalls Trafford. “I was only 59 at the time, and it was very unusual to get these cataracts and for them to grow so quickly. And basically at the rate they were growing more than likely I would lose most of my vision within a year.”

Just nine months earlier, at his previous check-up, Trafford had been told he had a “cataract situation” but that it wasn’t a big deal. The disease’s quick progression was a shock. His optometrist referred him to Dr. Robert Mitchell at the Mitchell Eye Centre, who told him about intraocular lenses (IOLs). Within a couple of weeks, Trafford was reclining in a chair, fully awake, as his cataractous natural lenses were replaced with artificial lenses.

Procedures like Trafford’s are not unusual. Cataract surgery is one of the most common surgeries in the world, and the most common type of eye surgery. But IOLs can be used to treat a variety of vision problems beyond cataracts.

Though different lens types exist, the implantation procedure is generally the same. After the patient is given a local anesthetic, an opthamologist inserts the IOL, usually made of silicon, acrylic and hydrogel, into the eye through a two- to three-millimetre incision in the cornea. Plastic side struts hold the lens in place. The procedure usually takes less than 30 minutes, and the patient can return to normal activities such as driving within two to three days.

Patients have several options of IOL procedures. With the Intraocular Collamer Lenses (ICL), the patient’s natural lens is left in the eye and the ICL is placed in front of it, just behind the iris. “In a younger person you don’t want to take their [natural] lens out because that’s what gives them reading vision,” says Dr. Sheldon Herzig, co-founder and medical director of Toronto’s Herzig Eye Institute. The candidates for these lenses are those aged 18 or above who have extreme nearsightedness, farsightedness or astigmatism, or who have a weak or very thin cornea the surgeon would not be able to do laser on. “The results are basically immediate. The next day, their vision is almost perfect.”

Alternatively, patients may have their natural lens removed and replaced by a lens implant that compensates for the eye’s refractive problems. This procedure is called Refractive Lens Exchange (or Clear Lens Exchange). Suitable patients are those with very high levels of nearsightedness or farsightedness, or with early lens opacities. During the procedure, which is the same as modern cataract surgery, a delicate instrument is inserted through an incision in the eye to create an opening in front of the lens capsule. A suction tip is inserted, the gel-like natural lens is gently suctioned out and a lens implant is inserted into the capsule.

Middle-aged patients may find refractive lens exchange a particularly attractive option, since it both corrects nearsightedness or farsightedness and prevents any future need for cataract surgery. “Once you get over 60, the quality of the human lens starts to drop off dramatically, and it becomes better to just do a lens exchange rather than just sticking a lens in [over the natural lens],” says Herzig, who performs about 100 phakic lens procedures and 2,000 lens exchange procedures a year.