iris, drawing a loop of the central segment of the suture out of the incision, and then performing a sphincterotomy inferiorly or distally. After the implantation of the intraocular lens, the ends of the suture are drawn out of an inferior or distal limbal self-sealing paracentesis and tied. This can dramatically increase exposure to the area in which most of the phacoemulsification takes place. Exposure is increased specifically at the distal portion of the capsulorhexis and the capsular bag, just under the distal capsular flap. This suture can restore an acceptable cosmetic appearance to the pupil postoperatively and remove the potential for unwanted glare.

An additional iris surgical procedure for pupillary enlargement is the pupilloplasty technique of Fine [14]. After lysing synechiae, partial-thickness sphincterotomies are made using Rappazzo scissors (Storz Instruments, E-1961-A) either through the paracentesis or through the cataract incision. The sphincterotomies cut full thickness through approximately one half the width of the musculus sphincter pupillae at each of the eight sites. Following sphincterotomies, each of the sites is stretched to the root of the iris. The author believes that this results in fracturing of the hyalinized fibrotic portions of the pupil and,stretching only the residual circular muscle in the pupil that was not transected. This technique usually achieves 6–7-mm pupil diameters, regardless of the initial size of the pupil. At the completion of the phacoemulsification and implantation procedure, a Lester type hook is used to mechanically return the pupil to as small a configuration as possible. The patient should use miotic drops and ointments postoperatively, to keep the pupil small and to avoid synechiae from the sphincterotomy sites to the anterior edge of the capsulorhexis. This technique tends to achieve an excellent cosmetic appearance postoperatively and also allows for more normal physiologic behavior of the pupil.

Osher has described pupillary membrane dissection [15] as a technique to allow the dilation of the pupil to an adequate diameter. This procedure involves meticulous dissection with a bent needle or microforceps to free and remove a fibrotic pupillary membrane. This technique is time-consuming and may produce some bleeding, but has proved to be a valuable aid in the management of some cases of small pupil.

In conclusion, phacoemulsification in the presence of a small pupil, continues to pose a challenge to the surgeon. However, the diverse techniques for the

management of these pupils, present us with options for reducing complications in these cases, to the standard low complication rate.

6.1.4Preoperative Preparation and Infection Prophylaxis

The state of the art of infection prophylaxis in cataract and refractive surgery continues to evolve, and therefore the standard of care remains a moving target. A plethora of reports have appeared in the scientific literature, which surgeons must weigh and consider. As a starting point, it is critical to realize that any data analysis should take into account, the multifactorial pathogenesis of postoperative infection. Studies which retrospectively review a case series, may easily fall prey to narrative fallacy and confounding errors. As David Chang recently pointed out, “… we must be cautious about making practice recommendations based solely on retrospective population studies with multiple covariables” [16].

6.1.5 Evaluating Risk

In the wake of the European Society of Cataract and Refractive Surgeons’ multicenter study of endophthalmitis, the Cataract Clinical Committee of the American Society of Cataract and Refractive Surgeons performed an on-line survey to characterize current practices among the members [17]. Of the 1,312 respondents, 90% reported an infection rate of less than one in one thousand. In general, the published incidence of endophthalmitis after cataract surgery in the peerreviewed literature, ranges from a low of less than one in five thousand, [18] to a high of about three in one thousand [19]. The risk of severe visual loss from endophthalmitis following cataract surgery has been put at one in six thousand [20]. For LASIK, the risk of infectious keratitis has been reported to be about one in three thousand [21].

For cataract surgery, factors which increase the risk of postoperative infection have been identified. Oliver Schein has pointed out that “consistent findings have been, excess risk associated with corneal incisions, age (especially over 80 years), and loss of posterior capsular integrity…” [22]. He notes that the “modest” increased

risk associated with corneal incisions “can be mitigated by expertise (i.e., close attention to wound construction and integrity).” This statement echoes closely whathas been said in the past [23].

In terms of prophylaxis, several approaches have demonstrated a reduced risk of infection. The use of povidone-iodine antisepsis has probably received the most universal support [24]. Chemoprophylaxis has demonstrated efficacy by various routes, and is widely employed. In the ASCRS survey, 88% of the surgeons used preoperative topical antibiotics and 98% used postoperative topical antibiotics. Intracameral antibiotic administration also received support: 30% of surgeons reported using this route either via irrigation or by direct injection. Subconjunctival administration can also be effective, although it is perhaps less appealing to surgeons performing clear corneal surgery with topical anesthesia, due to the stinging and pain it may engender [25]. Whatever the method is, killing bacteria on the ocular surface and inside the eye has value in the prevention of infection.

6.1.6 Assessing Your Approach

In the year 2004, David Allen and his colleagues presented a series of seven cases of endophthalmitis that occurred in a single surgeon’s practice during a 27 week period [26]. This surgeon’s incidence of infection rose precipitously to 1.6%. The surgeon stopped operating at this point. Statistical analysis suggested that these cases represented a true outbreak. After examining a variety of potential causative factors, including the timing of cases, nursing staff, equipment, patient risk factors and microbiology, they determined that the “only common contributory factor in each case was the surgeon.” A review of the surgeon’s technique determined that two weeks prior to the occurrence of the first case, the earlier practice of administering a subconjunctival antibiotic injection at the conclusion of surgery, had been discontinued. Following this analysis, the surgeon resumed his use of subconjunctival antibiotic injections and enjoyed a zero incidence of endophthalmitis in the subsequent 1,350 cataract operations he performed.

This cautionary tale demonstrates how a systematic investigation into an outbreak of infection, led to the correct causative factor. When infection strikes,

surgeons should first determine if the event represents a random and statistically expected event. If it does not, investigation is warranted to determine the cause. Casting a wide net by reviewing all the potentially relevant factors in an outbreak of infection increases the likelihood of finding the culprit. This approach is analogous to the one that is undertaken in looking for the source of outbreaks of noninfectious postoperative inflammation, such as TASS [27] and DLK [28].

Assigning the correct significance to the results of the published studies, as they apply to local conditions represents a second important lesson from this paper. At the time, subconjunctival injections were deemed “possibly relevant but not definitely related to clinical outcome” in Ciulla’s evidence-based update [8]. However, an earlier report had suggested a possible link [29]. Nevertheless, the key to understanding the outbreak lies in the fact that the subconjunctival injection represented the only antibiotic prophylaxis employed by this surgeon. Discontinuing the injection meant dispensing with all chemoprophylaxis. In a different setting, for example, the one where the surgeon uses topical antibiotics both pre and postoperatively, the discontinuation of subconjunctival antibiotics might not be significant.

Recently, Ng et al. performed a retrospective study of endophthalmitis in Western Australia from 1980 to 2000 by examining 205 cases of postoperative infection, and four time-matched randomly selected controls for each case. The authors found a significant impact from antiseptic preparation and subconjunctival antibiotic injection. Interestingly, antisepsis was nearly universal in both cases and controls, while subconjunctival injection was about 50/50 in controls and 30/70 in cases. Postoperative topical antibiotics were also nearly universal in both groups, while intracameral antibiotics were rare in both groups. Ironically, therefore, the power of the study to detect a significant difference for subconjunctival injections was higher than its power to detect a difference for antisepsis or topical antibiotics. The fact that, it did still find a difference for antisepsis confirms again the importance of povidone-iodine, and the fact that it did not find a difference for topical antibiotics does not mean that they are worthless.

Turning to wound location, Ng et al. did not find a significant difference between cases and controls based on scleral, limbal or clear corneal incisions. In a recent thorough review of the literature, Lundstrom concluded

Fig. 6.8 Optical coherence tomography of the anterior segment (Visante, Carl Zeiss Meditec, Dublin, CA) demonstrates the profile of a temporal clear corneal incision constructed with the 3D Trapezoidal diamond (Rhein Medical, Tampa, FL). The incision is constructed by placing the tip of the blade just anterior to the corneal vascular arcade and directing the knife toward the corneal apex in a single planar motion. The differentially beveled blade is designed to create a tunnel that is 2 mm in chord length

that, “There is no conclusive evidence of the relationship between clear corneal incision and endophthalmitis” [30]. Nevertheless, a clear corneal incision design and construction appear to be less forgiving than scleral tunnel incisions [31]. When reviewing the potential causes for infection, a leaky wound with hypotony represents a clear avenue for the introduction of bacteria into the eye. The use of correct architecture and the attainment of a Seidel negative closure are critical for the prevention of infection (Fig. 6.8) [32]. A single suture should be placed if necessary. Incision construction represents an important area for examination, when faced with an increased incidence of infection or if self-sealing cannot be routinely obtained.

6.1.7 Preventing Infection, Step by Step

Infectious disease subspecialists generally consider pathogenesis in terms of both, the resistance of the host and the virulence of the etiologic agent. Most cases of postsurgical endophthalmitis are related to normal flora of the eyelids and the ocular surface, for example, Staphylococcus epidermidis. Gram negative organisms, such as Pseudomonas aeruginosa, though

capable of more rapid destruction of tissue, occur less frequently. While the etiology remains fairly consistent, host factors may vary widely. The patient’s age remains as the most significant factor s. However, thorough examination of the ocular adnexa, with special attention to signs of blepharitis, eyelid malposition and lacrimal insufficiency or obstruction, forms an important step in assessing infection risk. Initial treatment with eyelid hygiene for blepharitis or definitive surgical treatment of ectropion or nasolacrimal duct obstruction makes sense, prior to cataract or refractive lens surgery. Less obviously, treatment of dry eye syndrome (e.g., with topical cyclosporine) prior to surgery may improve the quality of the tear film and strengthen its defensive mechanisms. The presence of poor or partial blinking due to a facial palsy may indicate a need for increased lubrication with artificial tears in the perioperative period. Consideration of host factors such as these may lead to special precautions in the setting of reduced resistance to infection.

Preoperative antibiotic prophylaxis to sterilize the ocular surface remains a mainstay of infection prophylaxis. Many surgeons begin topical antibiotics, especially a fourth generation fluoroquinolones, moxifloxacin or gatifloxacin, up to three days prior to surgery. Additional topical antibiotic is often administered in the immediate preoperative period along with mydriatic agents and nonsteroidal anti-inflammatory drops. Topical antibiotic administration is frequently continued following the surgery for a period of one to two weeks. Some surgeons have adopted perioperative oral antibiotic prophylaxis, as fluoroquinolones exhibit excellent penetration into the vitreous body.

Sterile preparation of the eye for the surgery forms the most critical aspect of infection prophylaxis, as has been shown by the nearly universal adoption of povidone-iodine. Important considerations for draping include, optimal ergonomic access to the eye, complete sequestration of the lids and lashes, and maintenance of fluid drainage away from the surgical field. Critical aspects of intraoperative technique include incision construction and avoidance of complications. In particular, compromise of the capsular bag is recognized as posing increased risk of infection. Surgeons should consider the use of intracameral antibiotic agents, either in the irrigation solution or as an injection into the anterior chamber. At the conclusion of surgery, the incision, whether clear corneal, limbal or scleral, must be checked for watertight closure, following the adjustment of the

Fig. 6.9 Seidel test is performed at the conclusion of the surgery after the intraocular pressure has been adjusted to a physiologic level. If persistent leakage occurs, stromal hydration is performed. Massage of the corneal surface with the side of a cannula sometimes facilitates the apposition of the roof and the floor of the incision, leading to sealing. Occasionally, a 10-0 nylon suture is required to effect closure

Fig. 6.10 Following sterile preparation of the skin, the upper eyelid is retracted with a 1 × 5 in. suture strip (Derma Sciences TP-1105). The strip is placed as close to the eyelid margin as possible

intraocular pressure to physiologic levels (Fig. 6.9). A leaky incision requires stromal hydration, massage or suture closure. Removal of the lid speculum and drapes should be accomplished without putting pressure on the eye. The postoperative exam is performed 2–24 h after surgery, and the patient is instructed to call the doctor immediately if there is increased pain and decreased vision.

6.1.8 Sample Protocol Outline

Fig. 6.11 The upper and lower eyelashes are covered with one Tegaderm, cut in half (3M NDC 8333-1624-05)

1.Topical fourth generation fluoroquinolone antibiotic (e.g., gatifloxacin or moxifloxacin), four times a day beginning three days prior to surgery, and continuing for two weeks after surgery.

2.Preoperative pledget solution (placed on the eye in surgical holding area)

Proparacaine 0.5%/phenylephrine 10%/tropicamide 1%/ flurbiprofen 0.3%/cyclopentolate 2%/gatifloxacin 0.3%

3.Sterile preparation

−Site prepped: quarter face

−Solution used on skin: 5% betadine

−Solution used in eye: 5% ophthalmic betadine with BSS rinse

4. Irrigation solution

500 mL BSS with 0.5 mg epinephrine 1:1,000, 4 mg gentamicin, 10 mg vancomycin

5.Draping protocol (Figs. 6.10–6.12)

−The eye should be dried around with a 4 × 4

−Disposable drape towel should be placed across the forehead

−The upper eyelid should be retracted with 1 × 5 in. suture strip and the strip should be placed as close to lid margin as possible (Derma Sciences TP-1105)