Management of intraoperative iris prolapse: Stepwise practical approach Naing L. Tint, FRCOphth, Amritpaul S. Dhillon, PhD, Philip Alexander, FRCOphth Iris prolapse is not an uncommon occurrence during cataract surgery. It usually occurs through the main incision during hydrodissection and is commonly associated with floppy-iris syndrome; however, it can manifest in cases with no known predisposition and can occur at any stage during surgery. The mechanism is explained by the Bernoulli principle and its effect on iris position during the movement of fluid within the eye. Predisposing factors are iris configuration, anterior chamber depth, and position and architecture of the corneal tunnel. Strategies for prevention and manage- ment include the use of pharmacological agents, ophthalmic viscosurgical devices, and iris retrac- tors. These strategies can be augmented by alteration and adaptation of the surgeon’s technique. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2012; 38:1845–1852 Q 2012 ASCRS and ESCRS Intraoperative iris prolapse during cataract surgery is not uncommon. It is associated with increased postop- erative inflammation, iridodialysis, hyphema, and transillumination defects resulting from iris trauma, 1–3 as well as an increased risk for posterior capsule rupture. 4 In this review, we discuss the predis- posing factors, preventive measures, and intraopera- tive strategies to deal with this complication. Intraoperative floppy-iris syndrome (IFIS) predis- poses to iris prolapse and has been addressed previ- ously. 5–7 This review will therefore focus on the general management of intraoperative iris prolapse during phacoemulsification cataract surgery in cases with and without IFIS. MECHANISM OF INTRAOPERATIVE IRIS PROLAPSE Although the etiology of iris prolapse is multifactorial, the basic mechanism is constant and can be explained by the Bernoulli principle; ie, in the context of inviscid (ie, nonviscous) flow, an increase in the speed of fluid occurs simultaneously with a decrease in pressure. Allan 8 has applied this principle to propose the mech- anism by which iris prolapses (Figure 1). In a closed eye, iris prolapse does not occur and well- constructed phacoemulsification wounds can with- stand intraocular pressures (IOPs) greater than 2000 mm Hg without iris prolapse. 9–11 However, the rapid outflow of aqueous that occurs during an open-globe injury or with a poorly constructed phaco- emulsification incision will cause a rapid reduction in the pressure anterior to the iris, relative to pressure posterior to the iris. This results in the iris drawing toward the wound with the potential for prolapse. It has been proposed that the effect of pressure changes on the iris are initially negligible until a critical point is reached, and at this point, iris prolapse is inev- itable (Figure 2). 8 However, the critical point is depen- dent on a multitude of factors, such as wound construction, iris configuration, and iris tonicity. 5,8 Other factors are listed in Figure 3. Wound Construction Small-incision sutureless cataract extraction re- quires meticulous wound construction. There is a gen- eral consensus that 2-step or 3-step incisions should be constructed. 15,16 Ernest et al. 10,17,18 advocate the con- struction of a “square” incision with a minimum inter- nal corneal lip of at least 1.5 mm. This has been shown to provide a self-sealing wound with minimal risk for Submitted: June 27, 2011. Final revision submitted: February 22, 2012. Accepted: March 11, 2012. From Cornea and External Eye Diseases (Tint), Moorfields Eye Hospital, London, the Department of Ophthalmology (Tint, Dhillon, Alexander), Queen’s Medical Centre, Nottingham, and the Department of Ophthalmology (Alexander), University Hospital Southampton, Southampton, United Kingdom. Corresponding author: Naing L. Tint, BSc, FRCOphth, Cornea and External Eye Diseases, Moorfields Eye Hospital, 162 City Road, London, United Kingdom. E-mail: ntint@talk21.com. Q 2012 ASCRS and ESCRS Published by Elsevier Inc. 0886-3350/$ - see front matter 1845 http://dx.doi.org/10.1016/j.jcrs.2012.08.013 REVIEW/UPDATE