AAO: Drop-free prophylaxis regimen before cataract surgery lowers treatment burden with caveats

Reviewed by Neal H. Shorstein, MD

Physicians at Kaiser Permanente have been using a prophylactic drop-free drug regimen before cataract surgery for more than a decade.

Their regimen is so streamlined that the only drop that patients receive in anticipation of cataract surgery is a supplemental dilation drop instilled preoperatively while they are still in the holding area, according to Neal H. Shorstein, MD, who discussed the topic at the American Academy of Ophthalmology’s virtual 2020 annual meeting.

Dr. Shorstein is an ophthalmologist, researcher and associate chief of quality at Kaiser Permanente Medical Center in Walnut Creek, CA.

This more efficient approach seems highly beneficial for patients because drop instillation is associated with a few risks, i.e., prescription error, failure to pick up the prescription, failure to adhere to the instillation instructions, and stopping the drops prematurely.

If only the correct instillation is considered, 93% of drop-naive patients have been reported to instill drops incorrectly. In addition, the bottle tip can become contaminated and it can cause microtrauma.

The resistance of bacteria to topical antibiotics is another issue, such that instillation periods that are too short or too long or repeated over time can result in bacterial resistance. Finally, and not to be overlooked, the drugs can be expensive.

Drop-free prophylactic regimen
The regimen begins with an injection of LidoPhen 1%/1.5% (cyclopentolate/tropicamide, VNH Pharmaceuticals Pvt, Ltd.) at the beginning of the surgery.

The surgery ends with an injection of at least 0.5 ml of intracameral moxifloxacin 0.1%.

However, 0.1 ml of cefuroxime 1% can be substituted in place of the moxifloxacin. Moxifloxacin also can be used for stromal hydration because recent data have indicated that the antibiotics remain in the wound for about 24 hours.

Finally, at least 4 mg of subconjunctival triamcinolone acetonide is injected at least 5 mm inferior to the inferior limbus. No perioperative topical nonsteroidal anti-inflammatory drug (NSAID) or steroid is used, Dr. Shorstein explained.

The rationale
The use of moxifloxacin in the manner described for stromal hydration and in an intracameral injection has been associated with low endophthalmitis infection rates.

This was supported by a meta-analysis that concluded that there was no supporting evidence that any postoperative use of topical antibiotics lowered the risk of endophthalmitis.

Another study found no difference in the endophthalmitis rates with or without the use of short-term topical antibiotics in conjunction with a regimen of intracameral antibiotics, according to Dr. Shorstein.

A look at the studies that evaluated triamcinolone injections during cataract surgery showed that similar or better control of inflammation was achieved with subconjunctival injection compared with topical steroid instillation or with a steroid plus an NSAID in the 2017 PREMED Study.

In the latter, the inflammation was well controlled in patients with diabetes who did not develop cystoid macular edema, but the intraocular pressure (IOP) was higher because of a higher subconjunctivally injected steroid dose, he pointed out.

That result leads to consideration of the importance of dose and injection site.

“Location is everything,” Dr. Shorstein said. “Injecting steroid closer to the limbus produces a higher concentration of the steroid in the aqueous and a higher mean IOP at 3 months compared with the same dose injected more posteriorly resulting in a lower aqueous concentration and a lower mean IOP.”

There is a tradeoff when injecting the drug more anteriorly. Pain and iritis are addressed but it carries the increased risk of higher IOP. Injecting more posteriorly should be more beneficial to the macula with less chance of IOP spikes ,but perhaps at the expense of enhanced pain and iritis control.

Initially, Dr. Shorstein reported, the drop-free regimen included the concentrated form of triamcinolone that resulted in some IOP spikes; with the same dose but injecting a greater volume (0.4 mL) of the dilute form of drug (10 mg/mL), fewer IOP spikes occurred and the physicians adhere to this practice.

“The most common problem associated with steroid injections is conjunctival hemorrhage that results from nicking a blood vessel during the injection,” he said. “This can be minimized by visualizing the needle tip and avoiding large vessels.”

Rarely, self-limited late hemorrhages months after the injections have been observed.

Drug reflux is another problem that can be avoided by tunneling the needle 2 to 4 mm under the conjunctiva and injecting slowly.

Dr. Shorstein also advises physicians to educate patients about the presence of the depot white spot and that it generally resolves in about 1 to 2 months and that, while IOP spikes occur infrequently, patients should have a checkup 1 month postoperatively.

Finally, when adhering to the dropless regimen, Dr. Shorstein noted the importance of instilling povidone-iodine 5% solution for 3 to 5 minutes, careful wound construction, leaving a relatively firm eye at the end of the surgery, and use of stromal hydration with an antibiotic.

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Neal H. Shorstein, MD
E: neal.shorstein@gmail.com​
Dr. Shorstein has no financial interest in this subject matter. The drugs mentioned are used off-label.