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The Never-ending Evolution of Cataract Surgery
Keep up with a growing list of cataract instrument options.
Wayne Bizer
Publish Date: April 3, 2008   |  Tags:   Ophthalmology

A whole new category of micro-ophthalmic instruments has arrived on the scene in the last several years to accommodate new phacoemulsification techniques and their smaller incisions. Two decades ago, a surgeon could have more than 20 instruments in his tray for cataract surgery. Today, most have fewer than a dozen, many of which, such as the Utrata forceps for tearing the capsulorhexis, have become smaller along with the phaco incision. Here's a review of the tools your surgeons pass through the 1mm side-port incision.

My, How Things Have Changed

Things have changed a great deal since I performed my first cataract surgery in 1974. For starters, today's procedure is dramatically safer and less stressful for both the patient and surgeon. Phacoemulsification, in which the central nucleus is broken into tiny pieces by ultrasound and aspirated out of the eye, is the biggest change in the last three decades.

Before phacoemulsification, which requires only a small incision, extracapsular cataract extraction (ECCE) was the most common method of removing cataracts. In ECCE, the whole hard nucleus is removed in one piece within its surrounding capsule or outer skin of the lens. This requires a large 8mm to 10mm incision and wound closure with sutures.

Since phacoemulsification became widely adopted, incision sizes have become smaller and smaller, first to 3.2mm, then to 2.8mm. Some ophthalmologists perform surgery with two 1.2mm phaco incisions in the bimanual micro-incision phaco technique.

But this technique requires widening the incision to accommodate the intraocular lens (IOL) and its insertion device. In Europe and Canada, lenses that will fit through a 1.8mm-incision are now on the market, but they've yet to be approved for use in the United States.

Over the years, these smaller incisions have let surgeons perform sutureless cataract surgery, which has shortened the procedure time, contributed to shorter healing times and decreased post-surgical astigmatism. Still, developing IOLs that can be folded into smaller sizes is a constant challenge as the length of the phaco incision continues to decrease.

— Wayne Bizer, DO, FAOCO

  • Speculums. The speculum shouldn't exert any downward pressure on the eye. It should also be dependable and easy to clean. Each surgeon likely has his preference in speculums. Some are spring-controlled, others are screw-controlled or a combination of both. I prefer the Lancaster speculum, which has a screw-controlled locking mechanism. It gives me more control because I can adjust the amount of force used to separate the eyelids, unlike a wire speculum which, because of its spring, creates the same amount of force in each case. Over the years, I've had problems with wire speculums, which tend to bend easily and can break at the welded joints.
  • Knives. Stainless steel, diamond, ruby or sapphire? The key to making an appropriate incision is being able to replicate it in every case. I find that diamond blades, because they're so sharp, make an incision with very little resistance, which can lead to better outcomes. These blades come in several different configurations, such as trapezoid, triangle and spear-like. Some have single bevels and some have double bevels to create a self-healing wound.

Diamond blades cost a lot more than steel blades ($500 to $3,000 each), but I feel that they are worth it, as long as you take proper care of them. Many companies offer diamond blade repair services. However, a diamond blade can become so dull, chipped or broken that it can't be repaired. With diamond blades, it's important that everyone who might handle the knife — nurses, techs and sterilization staffers — know proper handling and care of these delicate instruments. Stainless steel blades offer a less expensive ($16 to $25) option.

  • Capsulotomy needle. The capsulorhexis (rhexis is from the Greek, meaning "to tear") is a circular tear in the lens capsule or skin of the lens. I use a 26-gauge bent needle to incise the capsular bag in order to create the continuous curvilinear capsulorhexis. Once the tissue is torn, the flap can be advanced to create a circular opening into the lens and then removed with forceps. The capsulorhexis makes removing the crystalline lens safer and helps with positioning of the IOL.
  • Utrata forceps. Developed by Peter Utrata, MD, of Columbus, Ohio, these tiny forceps perform double duty. The sharp, angled tip can be used to begin the capsulorhexis in the same manner as with a bent needle. Afterwards it can be used to advance the tear in the capsule into a more or less round opening. The angled shafts allow for greater mobility in the capsule and their size makes them ideal for small incisions.

  • Choppers. In 1993, Kunihiro Nagahara, MD, of Japan, introduced horizontal chopping of the nucleus to the phacoemulsification process. The chopper is inserted through the side port. Chopping breaks the nucleus into "bite-size" pieces and requires less ultrasound energy to emulsify the nucleus. Since then, several instruments specially designed for chopping have been introduced. Some choppers have a tip offset at an angle, with a semi-sharp edge to break up the nucleus. Others have an irrigating cannula so that the surgeon can chop and irrigate at the same time.
  • Phaco tips. The surgeon's choice of phaco tips grows each year. They have different calibers, offset angles, bevels and shapes. Some tips are rounded with no sharp edge, while others have a tapered barrel. How the tip works has changed as well. Traditionally, the tip pulses back and forth. Some new designs have oscillating tips that move side to side. The goal of the oscillating design is to break up the lens material with less repulsion and less heat, which may prevent burning the cornea. When deciding on a phaco tip, it's important to factor the recommended lifespan of the tip. Some can be used as many as 20 times, while others are designed for fewer uses.
  • Lens injectors. Using an injector rather than forceps to insert an IOL has helped shorten procedure time in cataract surgery. The ophthalmologist's choice of IOL usually determines which injector will be used. Most manufacturers have a recommended injector for each IOL. Often the IOL manufacturer sells an injector designed especially for the lens. As the phaco incision size has become smaller, injectors have been designed to insert the lens through smaller tunnels. On the horizon in the United States is a preloaded injector for IOLs packaged in a pre-sterilized, disposable injector. These products have been available abroad for about five years and should hit the U.S. this year.
  • Lens cutters. When complications arise, you may need to explant the IOL. Foldable IOLs can sometimes be refolded and removed through a 3mm to 4mm incision. Otherwise, since an unfolded lens is much larger than the incision, it needs to be cut into pieces for removal. Surgeons have invented dozens of instruments to grab and cut the lens. Some are scissors, others are hybrid scissor-forceps. Most cutters have at least one serrated edge to grab the slippery IOL before cutting.

The duty to keep up
If there's one constant in eye surgery, it's change. Whatever we do today will ultimately find its way into the history book of eye surgery as newer and better instruments are developed. Keeping up with change is the duty of the ophthalmologist as well as the surgical facilities where the latest procedures are performed.

Why Titanium?

Because of the lights and magnification required for microsurgical procedures, it's best to use instruments that create as little glare as possible. Today, many instruments are made from anodized titanium with low-glare surfaces. Titanium's strength and light weight make it ideal for ophthalmic surgery instruments.