Cataract surgery is among the most common surgical procedures performed globally. Advances in technology and improvements in techniques, such as the clear corneal incision, small incision surgery and the use of a femtosecond laser, have made this procedure safe with excellent outcomes in an overwhelming majority of cases.
Cataract surgeons are always careful to prevent postoperative inflammation and microbial proliferation through the use of steroids, nonsteroidal anti- inflammatory drugs (NSAIDs), and antibiotics. Cystoid macular edema (CME) and postoperative infectious endophthalmitis are caused by uncontrolled inflammation and microbial proliferation, respectively, which can lead to suboptimal or even devastating outcomes. Therefore, every effective measure should be taken to prevent these complications.
The standard of care after cataract surgery
Traditionally, eye drop therapy throughout the perioperative period has been the mainstay in inflammation control and infection prevention after cataract surgery. Despite the advances in other aspects of cataract surgery, this has remained unchanged as the standard of care over many years.
However, there are some major drawbacks to topical therapy, including ocular surface toxicity, high expenses, unpredictable effective dose delivery and concerns associated with instilling eye drops, especially among inexperienced and poorly compliant patients, or those who need multiple drug administrations. As a result, dropless cataract surgery has become an interesting concept in recent years.
Recently, the introduction of triamcinolone acetonide-moxifloxacin (Tri-Moxi), which contains 15 mg/mL of triamcinolone acetonide and 1 mg/mL of moxifloxacin, has made dropless surgery a new option.
A promising substitute for standard eye drop therapy
Dr. Saman Nassiri and colleagues at the Loma Linda Eye institute, California, USA, conducted a retrospective longitudinal study in which they compared outcomes of patients who underwent cataract surgery using Tri-Moxi injection along with a postoperative nonsteroidal anti- inflammatory drug versus standard eye drop therapy. Results of this study were published in the June 2019 edition of the Journal of Cataract and Refractive Surgery (JCRS) in a paper titled “Comparative analysis of intravitreal triamcinolone acetonide-moxifloxacin versus standard perioperative eye drops in cataract surgery”. *
Currently, there is a paucity of clinical data available in the literature about the effectiveness of this new compound drug in cataract surgery. The authors hypothesized that the intravitreal Tri-Moxi injection can effectively control infection and inflammation after cataract surgery and be at least comparable to standard eye drop therapy.
Dr. Nassiri and co-authors reviewed electronic medical records of patients who underwent cataract surgery using Tri-Moxi injection, along with a postoperative nonsteroidal anti-inflammatory drug drop (Group 1). Group 1 was compared with patients who received a standard eye drop (Group 2) in terms of intraocular inflammation and corneal edema severity, and the rate of high intraocular pressure (IOP), postoperatively. Overall, a total of 1,195 consecutive eyes (Group 1 [681 eyes], Group 2 [514 eyes]) of 919 patients were included in the study.
The study authors showed that postoperative intraocular inflammation decreased at a faster pace in the Tri-Moxi group versus the standard eye drop group. Hence, the degree of intraocular inflammation was lower in the Tri-Moxi group compared with the standard group at week 1 and month 1 after surgery, respectively.
According to Dr. Nassiri and colleagues, “Intravitreal injection of triamcinolone acetonide-moxifloxacin during cataract surgery was non-inferior to standard eye drop therapy in the control of inflammation and corneal edema after cataract surgery”.
The rate of postoperative high IOP was comparable between intravitreal Tri-Moxi and standard eye drop regimens. It, therefore, represents a promising substitute for standard eye drop therapy, especially for patients who have poor compliance with eye drop usage.
Improving patient’s compliance postoperatively
Prof. Jod Mehta, who heads the Corneal and External Eye Disease Service and is a senior consultant refractive surgeon at the Singapore National Eye Centre, commented on the publication by Nassiri and colleagues. “There have been good strides in reducing the risk of postoperative infection over the last decade,” he shared. “Rates have certainly dropped in most countries through various interventions. The majority of patients still require the use of topical medications after surgery to control inflammation and reduce the risk of infection. Topical drops are effective in reducing these side effects. However, they are dependent on patients’ compliance on use. IOP control immediately postop is not a major concern for most patients in routine cases.”
In addition, he explained: “People are moving away from topical steroids to NSAIDS postoperatively due to possible issues in IOP control. In Asia, an added advantage of NSAID is the low risk of cytomegalovirus (CMV reactivation. As far a combination therapy goes, antibiotic plus steroid, as in this paper, has an appeal since it reduces the postop topical regime. However, as a single shot delivery, and assuming normal clearance from the vitreous, it is unlikely to have therapeutic effect after a few days. Hence, the antimicrobial pharmacokinetics is unclear.” Commenting further on intravitreal pharmacokinetics, Prof. Mehta explained that most patients present with acute endophthalmitis three to five days after surgery. “Even though the rates of infection in this study were similar to both groups, the pharmacokinetics will also be affected by the syneresis of the vitreous cavity, in that individual patient. The main issue of intraocular delivery of steroid is the risk of raised IOP, and method to reverse it if the drug is administered directly into the posterior segment. It is noteworthy that there was no difference between the two groups in this paper, but certain population groups are more prone to steroid-induced raised IOP.”
More importantly, Prof. Mehta emphasized: “Sub- conjunctival or extra-ocular delivery devices may be more preferred choices of delivery of such drugs as long as intraocular therapeutic concentrations can be reached. Depot injections, as used in this paper, or innovative, new drug delivery systems appear to be the way forward to improve patient’s compliance postoperatively.”
*Nassiri S, Hwang FS, Kim J, LeClair B, Yoon E, Pham M, Rauser ME. Comparative analysis of intravitreal triamcinolone acetonide-moxifloxacin versus standard perioperative eyedrops in cataract surgery. J Cataract Refract Surg. 2019:45(6):760-765.