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Intravitreal injection technique

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In this issue, we will explore the controversial subject of intravitreal injection technique. There are a number of different methods for administering intravitreal injections. Some controversial areas include: the use of sterile drapes and gloves, the use of topical vs subconjunctival anesthesia, and use of a lid speculum.

While we are not recommending any particular treatment for your patients, this column will be a nice exercise in exploring pro and con aspects of treatment decisions that we face daily. This column should be interpreted in the spirit of a debate society. I hope that you will find the column interesting, entertaining, and educational.


1. The use of sterile gloves and drapes during intravitreal injections

2. Topical vs subconjunctival anesthesia

3. The use of a lid speculum during intravitreal injections

Sterile Gloves and Drapes During Intravitreal Injections


Colin McCannel, MD: When performing intraocular injections, I am of the opinion that everything should be done to minimize risk. In my practice, I accomplish this by utilizing a full sterile prep, drape, lid speculum, and sterile gloves such as I would in surgery. Additionally, I administer antibiotic drops (oflaxacin or moxifloxacin). It is hard to assess the incremental risk reduction of adding any of the procedure steps. However, I think that Eyetech's VISION trial's reduction in endophthalmitis after changing, or improving, the intraocular injection procedure suggests that technique does matter. If the risk of endophthalmitis is approximately 1 in 1000, then it is almost impossible for any given practitioner to tell if their technique is better, the same, or worse compared to any other technique.

When in doubt, err on the side of patient safety. The only consideration is the best interest of the patient. The patient's emotional, socioeconomic, and real cost of vision loss from endophthalmitis outweighs any small incremental cost of the slightly more complex procedure.


Z. Nicholas Zakov, MD, FACS: In my opinion, sterile drapes and sterile gloves play a very small part in decreasing the risk of endophthalmitis during intravitreal injection. Key steps to avoiding complications when administering intravitreal injections are to use betadine on the cornea, conjunctiva, and lid margins, and to have a sterile needle enter the globe. Betadine produces a clean, but not necessarily sterile, external environment, not dissimilar to what is achieved in the OR during a "sterile" surgical procedure.

Informally, we have not seen an increased endophthalmitis rate by abandoning the use of sterile drapes and gloves when administering intravitreal injections in the manner described above.

Topical vs Subconjunctival Anesthesia for Intravitreal Injections


Joseph I. Maguire, MD: With any therapy, and its delivery, we look for effect, safety, convenience, cost, and patient comfort and satisfaction. In the delivery of intravitreal pharmacologic agents, topical anesthesia with 2% lidocaine gel delivers. Both topical and subconjunctival pre-intravitreal injection of anesthesia is effective. However, I feel topical anesthetic application is superior for the following reasons:  

Safety. Anytime an additional needle is in proximity to the eye, risk of inadvertent globe perforation is a small risk, but a risk nonetheless.

Convenience. Application of topical agents on a cotton swab pledget is fast and easy.

Cost. A sterile swab is less expensive than a disposable syringe.

Patient Satisfaction. Beyond the clinical effects of an intraocular injection, patient satisfaction is dependent on the comfort of the injection and post-injection cosmesis. Topical anesthesia provides superior comfort. In addition, conjunctival and episcleral vessels are better visualized and avoided, reducing risk of post-injection subconjunctival hemorrhage. A normal feeling and appearing eye is important to patients, especially when injections may be a monthly event for an indefinite period.


Keith A. Warren, MD: The proliferation of pharmacologic advances for the treatment of retinal disease and the need for intravitreal delivery of these drugs has given us the opportunity to debate over the method of anesthesia that is most effective for delivery of these drugs.

Subconjunctival injection is clearly a more effective and safe method for patients undergoing intravitreal injection when compared to topical application. The goal of anesthesia is pain control and subconjunctival injection provides a higher and more consistent level of drug to the ciliary body, which is the intended target site. Topical anesthesia delivers less drug due to variability in absorption of the drug through the conjunctiva. My observation has been one of inconsistent pain control with the application of topical anesthesia, but uniform pain control with subconjunctival injection.

In addition to reliable pain control, subconjunctival anesthesia is safer. It is not as toxic to the epithelium as topical lidocaine and is not a potential reservoir for
bacteria as is viscous lidocaine, thereby reducing the risk of infection.

While topical anesthesia is certainly quicker, if your goal is consistent pain control and safety, subconjunctival injection is your best bet.

Use of a Lid Speculum During Intravitreal Injections


Dennis M. Marcus, MD: Endophthalmitis is the major vision-threatening complication from intravitreal injections. The VISION study with Macugen alerted the retinal community to the need for meticulous sterile technique and use of a lid speculum to significantly reduce the endophthalmitis rate in patients undergoing repeated intravitreal injections. The key to endophthalmitis prophylaxis is to reduce the ability of normal periocular flora to gain entry into the eye. The eye lashes and lid margins harbor much of this flora. Use of a lid speculum decreases exposure of the lashes and lid margins to the entry site of intravitreal injections.

We use the lid speculum for vitrectomy, scleral buckle, and cataract surgery. Particularly in light of the VISION study data, why would anyone not use a lid speculum for intravitreal injections?


Moderator's Comment: While there are a number of retina specialists who do not routinely use the lid speculum during intravitreal injections, we have been unable to obtain a brief statement from any 1 physician. The typical reasons for not using a lid speculum include greater patient comfort, less conjunctival irritation, lower chance of corneal or conjunctival abrasion, and greater overall satisfaction of the patient during the intravitreal injection experience.

If patients are queried about the most uncomfortable portion of the intravitreal injection procedure, many may respond that the placement and removal of the lid speculum is the most uncomfortable part of the entire procedure. However, the use of the lid speculum serves to keep the lids and lashes out of the pathway of the needle and helps to give appropriate surgical exposure to the injection site. Due to the potential risk of endophthalmitis and the potential risk reduction of using a speculum,
it is understandable that the con position would be imprudent.

Although many years ago I tried performing intravitreal injections without using a lid speculum, I do not feel comfortable doing these injections without it, and always use a lid speculum during intravitreal injections.

Abdhish R. Bhavsar, MD, is an attending retina surgeon at the Phillips Eye Institute, director of clinical research at the Retina Center, P.A., in Minneapolis, Minn, and adjunct assistant professor at the University of Minnesota. He also serves as state chair of the Minnesota Diabetes Eye Exam Initiative. E-mail him about Face Off at