Reducing the need for postoperative eye drops

Take-home

One ophthalmologist proposes a practice-changing opportunity to eliminate the use of eye drops after cataract surgery.

Subtenon retrobulbar kenalog injection at the equator: Conjunctiva and tenons picked up at the caruncle and injection is made under the tenons to a depth of 7 mm. (Photo courtesy of James P. Gills, MD)

Tarpon Springs, FL-In a common scenario, eye drops prescribed for patients following cataract surgery typically include antibiotics, steroids, and non-steroidal anti-inflammatory drugs (NSAIDs).

The eye drops may be prescribed for up to 6 or 8 weeks, or longer in certain cases. In addition, adherence may be difficult for patients in regard to getting the drops into the eye(s), as well as monetary considerations.

Up until recently, the majority of telephone calls we received from postoperative patients were related to eye drop schedules-how and when to use them and refilling prescriptions.

Now, we seldom receive calls from patients regarding their eye drop schedule or refill requests.

A Korean study by Kim, Yang, Lee, and Park showed the effect of retrobulbar sub-Tenon’s injections of triamcinolone acetate (TA) on the progression of diabetic retinopathy after cataract surgery.1

A single dose of 40 mg/1 ml of TA decreased macular edema postoperatively for about 3 weeks and reduced the thickness of the retina to less than preoperative thickness for 6 weeks. This suggests that the effectiveness of the medicine is about 6 weeks.

None of the patients in this study had an elevation in IOP with the retrobulbar TA injections being placed behind the equator/retrobulbar space. This suggests that sub-Tenon’s injected posteriorly are not associated with IOP rises.

Many people have injected out of the 6 mm zone of the limbus and have not had pressure rises.

For years, drug-delivery implants have been studied by various companies in an effort to eliminate the need for postoperative drops. Though these implants are available, they are expensive and not reimbursable by Medicare.

We currently have a study in South Africa that consists of a 1 × 2 mm implant that is inserted into the capsule at the time of cataract surgery which will allow an NSAID to be slowly released through the eye over 7 weeks.

Other companies have used various forms of biodegradable delayed drug delivery systems to treat many forms of eye diseases. Although it appears that intraocular drug delivery implants may be preferred, they are not approved by the FDA or reimbursable by insurance companies.

Therefore, my protocol consists of 1.2 cc of triamcinolone acetate injected sub-Tenon’s equatorial/retrobulbar. I have done this in more than 10,000 cases since August 2009, which is the basis of this article.

Data

Patients receive medical screening to determine whether they were taking anticoagulants, have retinal disease, or have any other conditions or considerations.

If patients have diabetic retinopathy or macular degeneration, they may have the additional use of non-steroidals along with the retrobulbar kenalog. These patients are followed and checked with photo stress tests, optical coherence tomography (OCT), and visual acuity. About 1% of patients need added eye drops after the initial kenalog.

Thus, 85% to 95% of patients will receive 1.2 cc of subconjunctival kenalog in the superior nasal quadrant right above the medial rectus muscle going through the upper edge of the conjunctival fold or caruncle. This allows the kenalog to be placed essentially at the equator of the eye 1 mm above the medial rectus muscle.

Prior to instilling this, we use Xylocaine gel once before surgery and again just prior to the injection.

We also give a mixture of vancomycin, ceftazidime, and dexamethasone (1/10th of the therapeutic dose) in the anterior chamber at the end of the case.

Both the Mackool Eye Center and St. Luke’s have done 75,000 cases without endophthalmitis with the use of intraocular antibiotics.

Comment

This method does shift a greater responsibility upon the physician. Injecting the sub-Tenon’s area requires the surgeon to be able to pick up the conjunctiva and tenons, know exactly where the sub-Tenon’s area is, and inject under it.

Precision is of the utmost importance as it is easy to penetrate the globe if you are not used to doing this type of work. Several extremely good surgeons have started doing this but they ended up penetrating the globe so they gave up the injections.

It is important to develop a technique where you can pick up the tenons and have the needle go so the sharp part is vertical to the sclera and let the needle ride right along the crest of the sclera without catching or obstruction in the “feel” of the needle as it passes over the sclera. After the needle is mostly embedded to the area of the equator, the kenalog can be administered.

It has been known for years that if steroids are injected away from the trabecular meshwork, it will not cause an IOP rise. We have had fewer pressure rises with kenalog equatorially/retrobulbarly than we had with drops (less than one-fourth of 1%).

It has become a rarity to expect either endophthalmitis or pressure rises in our postoperative period. This added benefit of cataract surgery falls on the surgeon and is something that should only be done by those who feel they can actually benefit the patient more by this. Some physicians will not want to do this because of the time and the associated risk.

We have had fewer problems with kenalog injections than with local drops. With drops we have seen keratitis, corneal melts, and many other problems that we rarely observe anymore. We rarely see a medication keratitis with the equatorial/retrobulbar triamcinolone acetate and the postoperative period is extremely uneventful for both patient and physician.

This is presented as a continuation of use of retrobulbar injections of steroids that began more than 50 year ago. At that time, depomedrol was used. Kenalog injections are the “in-between” stage of delivery of medicine.

Most ophthalmologists would prefer an implant be available that can be inserted in the eye at the time of surgery to deliver medications; one with exactly the right dose and one that is reimbursable from insurance.

In the first years that we were doing sub-Tenon’s injections of kenalog we tried injecting various ways. We found that patients who were taking anticoagulants had the potential to bleed more than those who were not. Therefore, we do not perform injections on patients taking anticoagulants.

For patients with diabetic retinopathy and macular degeneration we review OCT images for any evidence of significant elevation of the retina due to either condition. The use of intraocular anti-vascular endothelial growth factor drugs and/or steroids may be used in the week prior to surgery to decrease the elevation, OCT images may be repeated and reviewed before and after surgery, and medications given accordingly. The exact way to treat patients with chronic diabetic retinopathy is yet to be ascertained; whether with injections or photocoagulation.

Another option that has been thought beneficial is chronic non-steroidal medications given over a period of years. This needs to be worked out and shown to be a significant return on investment capital. Time will tell whether intravitreal injections, photocoagulation or topical drops is the best form of therapy for each parameter.

At this point, patients have accepted the treatment of subconjunctival triamcinolone acetate because they save about $400 per eye on postoperative medications.

The next important factor is compliance. Patients do not have to worry about putting the drops in their eyes on time. There are many elderly patients that have a disability or live alone and do not have anyone to help them with this task so the kenalog injections allow them to have the medication they need without the added stress of adhering to a drop regimen.

The popularity of this among the patients has slowly grown. I call my patients the day after surgery to check on them and it is interesting that one of things they always marvel at is the fact that they do not have to use drops for several weeks after surgery like many of their neighbors did.

Summary

We have done 10,000 routine cataract surgery cases with sub-Tenon’s triamcinolone acetate 1.2 cc injections-mostly superior nasally in patients who are not taking blood thinners at the time of surgery-and thus, have eliminated the need for eye drops.

The only drops we use are lubricants to help with dry eyes after surgery.

Therefore, we will continue to use this regime until intraocular implants are available that will have a non-steroidal and eliminate the need for postoperative drops. It is also possible that the implant can be incorporated with an antibiotic so that we will not have to use our concoction for anterior chamber antibiotics as well. 

Reference

1. Kim SY, Yang J, Lee YC, Park YH. Effect of a single intraoperative sub-tenon injection of triamcinolone acetonide on the progression of diabetic retinopathy and visual outcomes after cataract surgery. J Cataract Refract Surg. 2008;34:823-826.

James P. Gills, MD, is founder and director of St. Luke’s Cataract and Laser Institute, Tarpon Springs, FL. He did not indicate a financial interest in the subject matter. Readers may contact Dr. Gills at jgills@stlukeseye.com or 727/938-2020.