Dr. Mayank Bansal
Associate Consultant,
Medanta-The Medicity, Gurugram
1. Is proper site preparation necessary for intravitreal injections?
Intravitreal injections are an integral part of ophthalmic practice and are now considered more office than OT procedures. However, the sterile precautions and proper preoperative site preparation and disinfection is still as important as for OT surgeries. Nentwich M et al evaluated the needle tip bacterial contamination (conjunctival bacteria) during the intravitreal injection procedure when following standard protocols. 550 intravitreal injections were evaluated for needle contamination after the procedure and compared with 200 sterile unused needles as controls. Standard preoperative preparation of the eye included 10% povidone iodine scrub on the eyelids, eyelashes, and forehead and irrigation of the conjunctival sac with 1% povidone iodine before the injection. Immediately 
after the injection, the needle points were rinsed three times in thioglycolate broth, which was then cultured at 35 degrees C for 5 days. The control needles were also dipped in the broth which was later cultured under similar conditions. The authors found that with a good site preparation, only 2 out of 550 (0.36%) needle points were contaminated after intravitreal injection. Staphylococcus epidermidis and Corynebacterium sp were isolated. All 200 unused needle points proved to be sterile. They concluded that even though the risk of infection/contamination was low, a very real possibility for introducing infection into the eye existed and that proper disinfection protocols should not be compromised.
Nentwich M, Yactayo-Miranda Y, Weimann S et al. Bacterial contamination of needle points after intravitreal injection. Eur J Ophthalmol. 2009;19(2):268-72.
2. Is it better to sterilize instruments at the OT premises and transfer them directly to the table or sterilize them at a distant CSSD facility and transfer them to the OT in a wrapping?
A retrospective study was published in American journal of Ophthalmology a few years ago which aimed to answer exactly this question. To determine if wrapping instruments in conjunction with full-cycle stea
m sterilization affects the incidence of postoperative infection in patients undergoing ophthalmic surgery in a dedicated eye center. The study evaluated 2 groups of approximately 19000 ophthalmic surgical patients and looked foror postoperative infection. For both groups, the surgical instruments were sterilized using full-cycle, steam sterilization, with a single major difference. The instruments for the first group were sterilized with equipment located adjacent to the operating room and no wrapping of the instruments was used, whereas for the second group, the sterilization equipment was located at a central facility and the instrumets were wrapped before being transported to the operating rooms. The study found 17 infections in the unwrapped sterilization group versus 9 in the wrapped sterilization group. Since infection rates for each group were so low, this apparent difference was not statistically significant. (P = .16). Similarly, differences found in the incidence of culture-positive cases of endophthalmitis (5 for unwrapped vs 3 for wrapped) were not statistically significant (P = .47). This study provides strong evidence that eye surgical facilities can, use either of these 2 methods of sterilization if proper guidelines are followed.
Carpel EF, Mancera AD, Rowan LL, Entine G, Entine O. Full-cycle steam sterilization in ophthalmic surgery-the effect of wrapping instruments. Am J Ophthalmol. 2012;153(3):405-411.e1.
3. Should chemical agents like Glutaraldehyde be used to sterilize instruments?
Use of chemical sterilization for surgical instruments and equipment is not considered an acceptable practice, yet every once in a while there are situations in the OR when it has to be done. A case series published in JCRS is a grim reminder to the danger that chemicals such as Glutaraldehyde pose to the intraocular tissues. Unal M et al d
escribed 6 cases of toxic anterior segment syndrome (TASS) after uneventful phacoemulsification cataract surgery. They mentioned that all cases were performed in the OT on the same day and presented with corneal edema, descemet’s membrane folds, anterior chamber reaction, fibrin formation, and irregular, dilated, and unreactive pupils on the next postoperative day. These cases were diagnosed as TASS and an investigation revealed that the cause was exposure to Glutaraldehyde 2% which had been inadvertently used to clean the instruments prior to steam sterilization. Unfortunately, none of the affected corneas improved and additional surgical procedures were required including penetrating keratoplasty, trabeculectomy, and glaucoma tube implantation in most cases. The authors concluded that the operating room staff involved in sterilizing instruments should be well educated about and careful to follow the protocols to properly clean and sterilize reusable ocular instruments. The lesson learned is that use of chemical agents for cold sterilization of intraocular instruments should be avoided and if at all there is a need to do so, thorough rinsing should be done.
Unal M, Yücel I, Akar Y, Oner A, Altin M. Outbreak of toxic anterior segment syndrome associated with glutaraldehyde after cataract surgery. J Cataract Refract Surg. 2006;32(10):1696-701.