In his letter, Spencer explores the value of postoperative patching as a strategy to reduce the incidence of infection after surgery. This question was, in some fashion, also raised by Faulkner.1 He suggests by allowing the patient to fully blink after surgery, topical anesthesia might contribute to a greater risk for infection, as lid “squeezing” might be associated with emptying the anterior chamber, subsequent ocular hypotony, and resultant influx of surface microbes into the anterior chamber. Faulkner suggests that we consider returning to injection anesthesia to avoid the above sequence of events.
Conversely, Spencer suggests that 24 hours of patching might obviate the need to consider injection anesthesia. A study by Wallin et al.2 suggests a statistical relationship between the use of an eye patch and the reduced likelihood of postoperative endophthalmitis. Could this be true?
Would eye patching and/or use of injection anesthesia by themselves protect against infection? I think not. However, consider the following scenario: Topical anesthesia allows the patient to blink, making it potentially more difficult to properly retract the eyelids and carefully drape the lid margins in preparation for surgery. It has been well established that the lid margins and eyelash follicles are the sources of the microbes that cause sporadic endophthalmitis in most cases,3 underscoring the need for careful draping. Furthermore, a patch is generally applied following injection anesthesia but not topical anesthesia. Hence, poor draping may be associated with the use of topical anesthesia, which, in turn, requires no patch. Conversely, injection anesthesia generally requires an eye patch but allows more careful draping.
In a guest editorial about the Wallin study,4 I observed that it was unfortunate that the study did not consider the relationship between the anesthesia type and the risk for postoperative infection. Nevertheless, in my view, the central issues are to establish a method of appropriate draping, irrespective of anesthesia type, and to create a clear corneal incision that is physically stable and will resist deformation in the early postoperative period. Toward that end, Belani and I5 investigated incisional stability in the early postoperative period. We demonstrated that clear corneal incisions that are square in their surface architecture and not distorted during surgery are physically stable, do not leak, and are not associated with ocular hypotony in the early postoperative period. It is my firm belief that incisional architecture and appropriate handling of the incisional tissue are the key elements in preventing microbial influx early postoperatively. An eye patch will not prevent eyelid squeezing unless the patient has also been subjected to injection anesthesia. Furthermore, use of a patch will not allow the patient to apply topical antibiotic and antiinflammatory agents during the crucial initial postoperative period.
I appreciate the comments of Spencer and Faulkner. However, I submit that rates of infection are, at best, only indirectly related to injection anesthesia and eye patching.
1. Faulkner HW., 2007. Association between clear corneal cataract incisions and endophthalmitis [letter], J Cataract Refract Surg, 33, 562.
2. Wallin T, Parker J, Jin Y, et al. Cohort study of 27 cases of endophthalmitis at a single institution. J Cataract Refract Surg. 2005;31:735-741.
3. Speaker MG, Milch FA, Shah MK, et al. Role of external bacterial flora in the pathogenesis of acute postoperative endophthalmitis. Ophthalmology. 1991;98:639-649. discussion by J Baum, 650.
4. Masket S., 2005. Is there a relationship between clear corneal cataract incisions and endophthalmitis? [guest editorial], J Cataract Refract Surg, 31, 643-645.
5. Masket S, Belani S. Proper wound construction to prevent short-term ocular hypotony after clear corneal incision cataract surgery. J Cataract Refract Surg. 2007;33:383-386.