Management of IFIS
Preoperative planning and anticipation of IFIS can impart significant protective effect in preventing major complications during surgery.[14,18,19] Chang et al. carried out a large prospective multicenter trial involving 167 eyes of tamsulosin patients operated on by 15 highly experienced surgeons. The surgeons were aware of the drug history and were allowed to employ appropriate compensatory measures to tackle IFIS. Results of this study demonstrated an incidence of posterior capsule rupture of 0.6% (95% CI: 0–1.8) and 95% of patients achieved a best-corrected visual acuity of 6/12 or more. Comparable data were also reported by other independent investigators and similarly reflect that the surgeon's awareness and anticipation of IFIS greatly influence the outcome of cataract surgery in this cohort of patients.[14,19,33–37] However, even for forewarned surgeons, patients who have a drug history that includes tamsulosin are still regarded as high-risk cases and can potentially be a challenge to the trainee surgeon. A retrospective review of 59 patients (81 eyes) taking tamsulosin at the time of cataract surgery and operated by trainees demonstrated an increased likelihood of complication with a posterior capsular rupture rate of 7.4% and a significantly prolonged operative time.
Nursing staff involved in preoperative assessment of cataract surgery should be educated regarding the implications of α-adrenergic receptor blockers and particularly tamsulosin on cataract surgery. A full drug history should be included in the physician referral letter and must be carefully reviewed before cataract surgery. Patients (males as well as females) should also be directly questioned regarding the use of tamsulosin, particularly as tamsulosin has recently become available without prescription in some countries and thus its use may not appear on communications from physicians. In addition, tamsulosin patients should be educated regarding their increased likelihood of a technically difficult operation and the potential intraoperative risks related to IFIS. It is vital that during the consent process, the patient is appropriately informed, thus allowing them to make better judgments on the 'risk-to-benefit' ratio of their surgery.
Primary care physicians' awareness of the association between tamsulosin and IFIS also needs to be increased. In a survey from an ophthalmic unit in the UK published in 2008, 96.8% of 64 physicians involved in patient referring were not aware of IFIS, although more than three-quarters of those physicians were prescribing tamsulosin to their patients. Although unsubstantiated, one would expect that physicians' knowledge regarding IFIS has improved in recent years given the increased awareness of IFIS within the ophthalmic community and the issuing of educational updates by ophthalmologists to physicians.[18,40] Generally, recommendations from ophthalmologists to physicians are not to change prescribing practices with regard to tamsulosin, but to educate their patients about IFIS and encourage them to disclose tamsulosin or other prostate medications use to their cataract surgeons.[18,40]
Stopping tamsulosin before surgery does not appear to prevent IFIS.[17–19] In the prospective tamsulosin trial, Chang et al. demonstrated that preoperative discontinuation of tamsulosin did not result in any difference in IFIS severity when compared with eyes of patients who continued to take tamsulosin. However, patients who stopped the medication had a slightly larger pupil size at the outset of the surgery (mean pupil diameter was 6.9 mm in stopped cases vs 6 mm in nonstopped cases) but this was not statistically significant. Moreover, stopping tamsulosin can aggravate LUTS and put the patient at risk of developing acute urine retention and therefore should be avoided.
Modification of Surgical Technique
Successful management of IFIS includes modification of routine surgical techniques. Attention to wound design with appropriately sized tunnels and entry anterior to the iris root may decrease the risk of iris prolapse during surgery. Use of gentle hydrodissection, low-flow fluidic parameters, bimanual irrigation-aspiration and microincisional phacoemulsification techniques increase anterior chamber stability and may also help reduce the magnitude of iris fluttering and prolapse to the phacoemulsification tip or to the wounds.[9,18]
Preoperative use of atropine eye drops can help avoid progressive miosis seen with IFIS[33,34] and was first suggested by Masket. Atropine blocks the cholinergically mediated action of the iris constrictor muscle, resulting in improved pupillary dilatation. When used to prevent IFIS, atropine drops need to be started at least 2 days before surgery. In the prospective tamsulosin trial by Chang et al., preoperative atropine was infrequently used by surgeons in the management of IFIS, and although eyes that received topical atropine drops had the largest mean pupil diameter preoperatively (7.2 ± 0.9 mm), 58% of these eyes required an additional intraoperative measure to manage IFIS. In addition, systemic absorption of atropine can increase LUTS in patients with BPH and thus it is important to inform the patient's primary care physician about the plan of management and not to discontinue tamsulosin.
Other pharmacological methods for IFIS management include the use intracameral α1 receptor agonist drugs[34–37] as a means to counteract the effect of tamsulosin on the iris receptors (Figure 2). This modality was not investigated by the prospective tamsulosin trial as the trial was initiated before the introduction of this class of drugs into the management of IFIS. In 2006, Sugar was the first to describe the use of intracameral epinephrine for the prophylaxis of IFIS. His regimen includes intracameral injection of diluted preservative-free epinephrine at a 1:4000 concentration at the beginning of surgery before the installation of the ophthalmic viscosurgical device (OVD). He reported uniform success to prevent IFIS in 71 operated tamsulosin patients. Using the same concentration of intracameral epinephrine in combination with preoperative atropine drops, Masket and Belani also reported a high success rate in the prevention of IFIS in a study of 20 eyes.
Intracameral phenylephrine. (A) Iris billowing and pupil constriction in intraoperative floppy iris syndrome. (B & C) Absence of iris billowing and pupil dilatation after injection of intracameral phenylephrine.
Image © Sallam, El-Defrawy, Ross, Bashir & Towler.
Manvikar and Allen used diluted intracameral phenylephrine (1:360) prepared from single-use minims in 22 eyes of tamsulosin patients that had small pupils preoperatively or displayed IFIS features intraoperatively. Additional pupillary dilatation was observed in only 73% of eyes. However, in all eyes that had intracameral phenylephrine owing to significant iris prolapse into the incisions or progressive miosis, it resulted in restoration of iris tone, decreased tendency to flutter and prolapse and caused the pupil to dilate back to its preoperative size. Similar results were also reported by Gurbaxani and Packard in another study of seven tamsulosin subjects using an intracameral phenylephrine concentration of 1:200. Potential ocular toxicity remains a concern with the use of intracameral drugs, although recent safety studies showed that phenylephrine and diluted epinephrine had no discernible deleterious effect on either the corneal endothelium or the macula.[42–45] It is worth mentioning that intracameral use of α-1 receptor agonists may be associated with systemic side effects, and blood-pressure spikes have been reported.
Mechanical measures to dilate the pupil and restrain iris movement have been tried with varying success in IFIS.[47–52] Viscomydriasis using Healon5® (sodium hyaluronate 2.3%) is one of these measures. The highly concentrated long-chained molecules of this higher viscosity OVD are able to move the iris effectively, dilate the pupil more than any other OVD and mechanically decrease iris billowing and prolapse. However, the main shortcoming of this method is that Healon5 in the anterior chamber tends to be consumed during surgery, but this may be minimized by using slow-motion fluidics for phacoemulsification and irrigation aspiration. Caution is also needed when using Healon5, as overfilling the anterior chamber can result in difficult manipulation of the anterior capsule and can also predispose to corneal wound burn.[54,55] Creating a fluid space around the phacoemulsification tip before starting phacoemulsification should circumvent these problems. This can be performed by partially filling the anterior chamber with the OVD and injecting balanced salt solution underneath, as described by Arshinoff in the ultimate soft-shell technique.
Iris retractors (hooks) are commonly used for tackling IFIS.[17,18,48–51] They can dilate the pupil and resist the tendency of the iris to billow and prolapse. Compared with Healon5, Iris retractors have the advantage of maintaining a constant pupil size during the surgery. While most surgeons usually employ four hooks to stretch the iris in a square or diamond configuration,[56,57] different techniques for placing the hooks have been described, including the use of a single hook posterior to the main incision, two iris hooks to straddle the main incision and inserting five hooks in a pentagon shape. Placing four hooks in a diamond configuration offers several advantages in IFIS and has been recommended by the American Society of Cataract and Refractive Surgery (ASCRS) committee for managing IFIS. The subincisional iris is pulled posterior to the phacoemulsification wound through a separate incision, making prolapse far less probable (Figure 3). In addition, this technique maximizes pupillary dilatation infront of the phacoemulsification tip and provides more space for cataract removal.
Iris retractors placed in a diamond configuration. Image © Sallam, El-Defrawy, Ross, Bashir & Towler.
Pupil expander rings have been used successfully for managing IFIS. Similar to hooks, pupil expander rings restrain the iris movement and decrease the severity of billowing and prolapse to the incisions. In general they are less traumatic than iris hooks, do not overstretch the iris and can be inserted without the need of additional incisions. Several designs are available, including the Morcher Pupil Ring® (Figure 4), the Milvella Perfect Pupil® and the Eagle Vision Graether Ring®. The Malyugin Ring® is the newest form of pupil expansion devices and, compared with the other pupil expansion rings, it has the advantage of being thin and light and hence easier to insert and remove in eyes with shallow anterior chambers using a special injector. Two sizes of this ring are now available; 6.25 and 7 mm. The 6.25 mm is the commonly used size and is easier to insert in eyes with shallow anterior chambers (Figure 5). The 7-mm device has recently been introduced and could be helpful in cases of IFIS with very flaccid iris to increase exposure and keep the iris further way from the surgeon's working plane. In a study of 30 eyes with IFIS, Chang reported excellent results with the Malyugin device in terms of maintaining a constant pupillary expansion of 6 mm and decreasing iris billowing. No major intraoperative adverse events were reported by the author, but iris prolapse still occurred in some cases.
Morcher pupil ring®.
Reprinted courtesy of Youssef T, Cornwall Community Hospital, ON, Canada.
6.25-mm Malyugin® pupil expansion device.
Image © Sallam, El-Defrawy, Ross, Bashir & Towler.
The best strategy for managing IFIS is still not known.[17,18,48] A surgeon's choice is mainly based on personal experience and case difficulty. Different modalities can also be complementary when combined and having experience with more than one method is an advantage, particularly as clinical circumstances may change during surgery.[18,48] Data from the 2008 ASCRS survey that was completed by 957 members showed intracameral α1 agonists and iris hooks to be the most preferred methods in managing IFIS (38 and 23%, respectively), although a third of respondents in this survey also reported that they routinely use more than one strategy for managing IFIS. The practice pattern of ophthalmologist in the UK has been reported to be in favor of using iris hooks and Healon5 in managing floppy irides. In a nationwide survey of consultants' experiences published in 2007, 61% of the participants reported using hooks and 27% used Healon5. Intracameral phenylephrine was uncommonly used in this survey, with only 2% of surgeons employing this technique; however, 12% of the respondents reported that they would consider using this modality in future.
Expert Rev Ophthalmol. 2011;6(4):469-476. © 2011 Expert Reviews Ltd.
Cite this: Review and Update of Intraoperative Floppy Iris Syndrome - Medscape - Aug 01, 2011.