Diamond keratomes are my favorite instrument for creating the main phaco incisions because they are exquisitely sharp and they make the absolute cleanest incision that seals the best. But the downside is that the diamond keratomes are expensive, several thousand dollars each, and surgeons often have a dozen or more of them spread across multiple surgical trays. The technique of using diamond keratomes is different than using steel blades, so there is a bit of a learning curve. The most important difference is that there is virtually no tactile feedback when using the diamonds because they have such an incredibly fine edge which makes them many times sharper than steel.
The angle of approach for a diamond keratome will generally determine the tunnel length of the incision. Remember the 3 basic rules of corneal incisions states that the tunnel length must be appropriate in order to provide good access, water-tight sealing, and an astigmatically neutral effect. For nearly all cases where I use a diamond keratome, the goal is to make a single-plane incision.
Diamond keratomes are incredibly thin in order to be exquisitely sharp. This means that they are also fragile: the edge is brittle and touching it with a metal instrument will cause it to chip and dull. Special methods must be used to clean diamond keratomes between uses. If care is taken during their handling, the diamond keratomes can stay sharp for thousands of surgeries. If they dull, they can be re-sharpened or re-honed a finite number of times.
I encourage you to try using a diamond keratome for your cataract surgeries. You will find that they are a pleasure to use and they can provide benefits that steel blades simply cannot. Do keep in mind, I still use steel blades for some of the surgeries that I do, and the results are still great.
And how do diamond keratomes compare to the femtosecond laser? As of now, 2018, the diamond keratomes create a far better incision than the femtosecond lasers. Even in cases where I use a femtosecond laser for part of the cataract surgery, I will still use a diamond keratome for the main phaco incision. Ultimately, the choice of blade depends on the surgeon’s preference and the clinical situation.
Click below to see a diamond keratome in action:
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