The Modern Automated Vitrector: A Good Friend to Have Around
Maurice J. Oakley, Lorie A. Logan · Journal of Cataract & Refractive Surgery · 2000
Holes and tears in the posterior capsule are probably more common than we want to admit. When these are treated properly, the visual outcome will not be compromised and our skills as cataract surgeons will be greatly enhanced. Our older patients often delay having their cataracts removed. This can lead to a hard, dense cataract. When the density of the cataract increases, phacoemulsification time is increased and more stress is put on the posterior capsule. The removal of this type of cataract, even in the best of hands, can cause tears in the posterior capsule. Some holes and tears go undetected, but most are readily seen. The hole in the capsule is not the problem. Vitreous that seeps through the hole and into the anterior chamber can lead to postoperative complications such as a peaked pupil, a slightly decentered intraocular lens (IOL), and decreased visual acuity. As long as the vitreous face remains intact, a hole in the posterior capsule can be covered with viscoelastic material and converted to a posterior capsule capsulorhexis, with an IOL positioned. How often, though, does the vitreous face remain intact? Vitreous is not always readily visible at the time of the initial surgery or even on the first postoperative day. Cortical remnants, corneal haze, or vitreous under the iris can and does cause the vitreous to evade detection. All of us have been taught that an iris sweep, gently moved over the capsule defect, can sometimes detect vitreous, but even this is not foolproof and only works a small percentage of the time. The best precaution I have found to ensure no vitreous is left in the anterior chamber is to gently pass an automated vitrector through the anterior chamber. This can be done before or after the IOL is placed. The modern automated vitrector, when used by an experienced cataract surgeon, is not an instrument to be feared. It can even give clues to where unseen vitreous resides. The pulsating action of the instrument will cause the edges of the posterior capsule hole to move “in time” with the instrument's pulsation. The iris will also move in a similar manner if vitreous is on or under it and the vitrector is engaged. When this action stops, you can be assured the vitreous has been removed. Remember, the automated vitrector is basically an irrigation/aspiration handpiece that has chopping ability. When used gently, it has less potential for complications than the phacoemulsifier. In our clinic, this technique has enabled our patients to have the same postoperative acuity they would have if no capsule hole were present the day following surgery. To accomplish vitreous removal from the anterior chamber in a gentle and harmless way, the infusion must be at a very low rate. Too much infusion will force more vitreous through the break in the capsule into the anterior chamber. Too little will collapse the chamber. The vacuum setting is also critical. Remember, less is better. Low infusion and low vacuum combined with high cutting speed will greatly decrease the possibility of enlarging the capsule defect or forcing more vitreous into the anterior chamber. To remove it, move the vitrector handpiece slowly through the anterior chamber, keeping the port up, and slide the handpiece gently over the iris and capsule. With clear corneal incisions the wound is also gently swept. With the use of the vitrector in this way, capsule defects and vitreous in the anterior chamber need not be the foreboding omen they once were. The gentle use of the automated vitrector will add to your proficiency as a cataract surgeon and keep your visual outcomes to predicted levels. Maurice J. Oakley MD Lorie A. Logan OD aAshland, Kentucky, USA