Preventing Intraocular Infection and TASS

Review these 12 risk areas with your colleagues and staff.

BY PERRY S. BINDER, MD

TOXIC ANTERIOR SEGMENT SYNDROME (TASS) can cause fixed, dilated or distorted pupils; iris atrophy; loss of best-corrected distance vision; cystoid macular edema; anterior capsular phimosis; posterior capsular opacification; and secondary glaucoma with optic nerve damage.

The best treatment for TASS is prevention. I recommend that if even one case occurs, you sit down with your staff and go through all potential risk factors one at a time.

Enzymatic cleaner: One day I was having lunch with my partners and said, “I’ve seen several instances of diffuse lamellar keratitis (DLK) with my LASIK cases in the last week. What about you guys?” They responded, “You know, we’ve noticed a lot more too.”

We sat down with the staff, who assured us that they were doing everything the same. When we asked how they handled the enzymatic cleaner, they explained, “We make up a fresh batch every month in a metal container and use it to digest the proteins on the instruments.”

When we went back and looked at it, we saw filaments floating in the enzymatic cleaner. We learned that when you keep the cleaner for more than a week, fungus starts eating the enzyme proteins. We were introducing fungus into our LASIK cases.

The bottom line: be sure that your staff prepares and maintains the enzymatic cleaner in the safest recommended way. We went through the list below together and I recommend that you and your staff do the same.

Detergents: How do your staff members mix the detergents when they clean your instruments? And are the instruments rinsed properly? Instruments usually go from detergent to several repetitions of diluent, but they carry over some detergent into the diluents. By the third or the fourth tray, you have detergents where you shouldn’t have them — something you have to carefully eliminate.

Ultrasonic baths: Ultrasonic baths can become contaminated, primarily with cell walls of gram-negative organisms, leaving endotoxin behind. You have to clean the baths thoroughly or use steam cleaning as well.

Antibiotic concentrations: Be careful not to put antibiotics into the eye in inappropriate concentrations or use antibiotics improperly mixed with diluents when you inject them into the anterior chamber. Talk to yourself and go over this three times before injecting any medicine in the eye for fear of putting in the wrong materials.

Preserved epinephrine or glutaraldehyde: Some surgeons have caused infection with contaminated unpreserved epinephrine. In other cases, surgeons have used glutaraldehyde that was not properly cleaned off the end of their instruments.

Skin prep agents: Povidone-iodine can potentially get into the eye, as clear corneal incisions may have access to the cul-de-sac that can move retrograde and get into the anterior chamber.

Gloves: Certain powdered gloves have been associated with TASS, but powder-free gloves have been reported to cause problems as well. If you touch the gloves to your instruments and the instruments go into the eye, a contaminated glove can cause infection.

pH irrigation solutions: Improper acetylcholine chloride (Miochol E) mixing is associated with TASS, as are potential endotoxin contaminants in indomethacin tromethamine salt.

Single-use products: Reuse of single-use products is very common, typically as a means of saving money. These instruments are not designed to be cleaned. Contaminants can stay inside them, and when they get cooked, those contaminants change the wall structure antigenically. If they’re put inside the eye, you’ve got trouble.

Equipment cleaning and maintenance: Insufficient cleaning, such as poor flushing of reuseable cannulas, is a very common source of contamination. In addition to cleaning adequately, be sure that your staff only uses sterile saline or sterile distilled water to rinse instruments.

Preservatives: BAK, bisulfites, metabisulfates: Any preservatives can damage the endothelium, iris, or lens capsule when used improperly, so it is best to have the injectables prepared by your staff or by a trustworthy pharmacy.

Denatured ophthalmic viscosurgical devices, intraocular lidocaine, trypan blue: These substances can be contaminated, and trypan blue can cause infection or damage the endothelium if it’s not prepared properly.

Cause unknown: The final potential case of TASS is no established cause. You can go through this entire list and not find a cause for your case. An antigen came from somewhere, but you don’t know where. Still, I recommend that you walk through this list with your staff every time you see a case.

It’s also important to tell your staff, “Please do not change any steps in what you do without discussing it with me first.”

Finally, stay on top of infection control in the literature and discuss it with your colleagues. Discuss any changes that you make in terms of medications, instruments and techniques so that everyone is ready to adopt them without any problems.