Surgery

Post-op cataract medications primer

Understand the common methods of preventing infection and controlling inflammation.

BY ELIZABETH YEU, MD

During cataract surgery, we remove a dysfunctional, clouded lens and replace it with a clear, man-made lens. To ensure optimal outcomes, we focus on two basic medical goals: preventing post-operative complications (namely endophthalmitis) and promoting recovery from post-operative inflammation, in all forms, as efficiently as possible. We want to be mindful of patient satisfaction throughout the surgery process, which is linked to high quality post-operative vision, ease of compliance, faster healing, and the absence of pain.

Preventing infections

While rare, endophthalmitis can have devastating consequences, including permanent vision loss. To prevent endophthalmitis, one tactic is the use of povidone iodine before surgery. Studies have shown that preoperative antisepsis with povidone-iodine 5% is helpful in eliminating approximately 45% of bacterial concentrations.¹ More often in the United States, the standard of care includes post-operative antibiotic drops. A few popular choices can be utilized as off label between two and four times a day, and third- and fourth-generation fluoroquinolones are commonly used. Some compounding pharmacies have combination drops (Ocular Science, Imprimis) by incorporating two or three of the post-op medications within one bottle, which can be easier and less expensive for the patient.

Intracameral and intravitreal antibiotic and/or steroid injections at the end of surgery appear to provide a promising alternative to post-operative antibiotic eye drops. Intracameral antibiotics are standard of care in some European countries, and some studies demonstrate superiority to peri-operative drops. In one recent study, none of the 25,920 patients who received intracameral cefuroxime developed endophthalmitis. By contrast, patients who received topical or systemic preoperative antibiotics or postoperative subconjunctival injection had only a 40% to 50% reduction in occurrence.²

Controlling inflammation

Any kind of surgical trauma stimulates the inflammation cascade. The risk increases with age, cataract density, iris pigmentation, increased surgical time, diabetes, autoimmune diseases, and ocular comorbidities.

Persistent inflammation can lead to cystoid macular edema (CME), which can significantly impact visual acuity, cost of care, and patient satisfaction.

We can treat the top of the inflammation cascade using topical steroids to inhibit phospholipase A2, inhibiting the release of arachidonic acid and arachidonic acid metabolites, including prostaglandins. Further down the cascade, we can use non-steroidal anti-inflammatories (NSAIDs) to shut down formation of prostaglandins with Cox-1 and Cox-2 inhibition.

Topical NSAIDs can be used pre-operatively in order to prevent meiosis, a clinical manifestation of prostaglandins, and maintain a more dilated pupil. Topical NSAIDs are not specifically indicated on-label to prevent CME but are commonly used for this reason. Post-operatively, topical NSAIDs have been shown to effectively decrease anterior chamber inflammation and changes to the macular thickness. Literature on this topic shows less alignment on whether adding NSAIDs in addition to steroid therapy can more effectively reduce the incidence of macular edema as compared to topical steroids alone. A review published by the AAO in 2015 concluded that, based on the available literature, there was no added benefit of NSAID plus steroids vs. steroids alone to prevent CME.³ In contrast, a more recent prospective study demonstrated topical bromfenac 0.1% and ketorolac 0.45% plus a topical steroid was more effective at treating post-operative anterior chamber inflammation and preventing macular thickening than topical steroids alone.⁴ Newer anti-inflammatories are potent and effective with less frequent dosing. Once-daily dosing will likely improve compliance and prevent discomfort.

Injection delivery options

Injection as a delivery method reduces the burden of post-op drugs. It might allow patients to apply just one drop once a day, compared to using three drops upwards of four times a day (between antibiotics, steroids, and NSAIDs).

Some clinicians are exploring the use of intravitreal injections at the end of surgery, administering combinations of steroids and antibiotics in one syringe using a sterile preparation from a large national compounding pharmacy (Imprimis). Popular choices are moxifloxacin and triamcinolone with or without vancomycin.

Risks of this approach include bleeding, zonular damage, capsular rupture, vitreous manipulation, retinal toxicity or detachment, steroid-induced IOP rise, need for additional steroids, and postoperative floaters. However, clinical results are promising, with only a 1.2% incidence of post-op clinically significant CME, as reported by Dr. Jeffrey Liegner from his prospective study performed on 975 patients.⁵ Potential advantages include better compliance, greater convenience, reduced cost, greater patient satisfaction, and less confusion for co-managing physicians.

This is a new delivery method, but personal correspondences with John Berdahl, MD, suggest that a low incidence of complications could lead to use for prophylaxis of endophthalmitis and decreasing inflammation.

We also have branded vs. generic options. More branded medications used after cataract surgery are indicated at less frequency, specifically within the NSAID class. They can be used once daily versus generics that are indicated for four times daily use. In comparing the adverse events of the medications, from a corneal specialist perspective, the ocular surface looks better with less frequent use, and the vehicle in branded options can be friendlier to the ocular surface than with generics.

New approaches

Post-operative endophthalmitis is closely linked to skin flora, with gram positive staphylococcal and streptococcal species among the most common.⁶

Of the S. aureus endophthalmitis rates, MRSA is on the rise and may comprise upwards of 41%.⁷ Similar to the sterilization provided by betadine pre-operatively, it may be possible that pre-operatively decontaminating the skin and lid margins could lower endophthalmitis rates. A relatively new treatment indicated for blepharitis is topical hypochlorous acid spray, which was introduced to the market in 2015. One promising approach is to decontaminate the naturally existing skin flora prior to surgery by using topical hypochlorous acid applied to the lids. Hypochlorous acid is currently available, and its strengths include a high bacteriocidal rate, including against MRSA.⁸

Some measures currently taken will likely phases out over time, because using these medications before, during, and after surgery may not necessarily be preferable. Sustained-release medications should continue to reduce the burden on patients, and dropless cataract surgery is becoming a reality for an increasing number of practices.

Alternative drug delivery devices are also under development. For example, a sustained-release dexamethasone punctal plug (Dextenza, Ocular Therapeutix) is a promising newer technology to help the burden of post-operative medications. Between new delivery methods and compounded meds, inflammation management may look vastly different in five to 10 years.

Current measures are effective for the most part, but we must keep our patients’ compliance and comfort in mind. Beyond surgical anatomical success, functional success is measured by patients’ satisfaction. One study looked at 306 cataract surgery patients’ experiences in the recovery room and asked them to rank moderate to severe pain. Approximately one third of patients had enough pain to require oral pain medication. For this group, post-operative pain was a significant predictor of patient dissatisfaction.⁹

If there are ways we can improve the recovery process, and make it easier for patients, then we need to strive toward that outcome. OP

For references, see the online version of this article at www.ophthalmicprofessional.com

	Elizabeth Yeu, MD, is assistant professor of ophthalmology at Eastern Virginia Medical School and in private practice at Virginia Eye Consultants in Norfolk, Va. Contact her at 757-622-2200 or eyeu@vec2020.com.
	Disclosures: Dr. Yeu is a consultant to Allergan, Alcon, AMO Bausch + Lomb, Ocular Science, Ocular Therapeutix, and Ocusoft.