Several authors1–4 have reported challenges in phacoemulsification cataract surgery in previously vitrectomized eyes. These include posterior capsule plaque, zonular instability, and fluctuations in anterior chamber (AC) depth. Abnormal AC deepening is usually associated with mydriasis and can be accompanied by paradoxical AC shallowing with miosis. This phenomenon has been termed lens–iris diaphragm retropulsion syndrome (LIDRS).5 Eyes that have had extensive vitrectomy are at greater risk for this syndrome than eyes that have had only core vitrectomy.1 We describe a simple maneuver that can stabilize AC depth and allow safer phacoemulsification.
Abnormal deepening of the AC usually occurs immediately after introduction of irrigation (with a phaco tip or an irrigation/aspiration [I/A] tip) (Figure 1, A, B). By introducing a second instrument (eg, a short, blunt-ended chopper) through a second port and placing it between the iris and the anterior capsule, irrigation fluid can be directed under the iris (Figure 2). As the vitreous volume is restored, AC depth and pupil diameter will normalize (Figure 1, C). To avoid irritation, only the tip of the second instrument should be placed under the iris. Once the second instrument has been correctly placed, it takes about 3 seconds for the AC depth to normalize, which allows sculpting to continue in the usual manner.
When the irrigation is removed and reintroduced (eg, during changeover from sculpting to I/A), the AC becomes abnormally deep. The maneuver just described can then be repeated; once satisfactory AC depth is achieved, all soft lens matter can be removed in the usual manner.
In 1994, Wilbrandt and Wilbrandt5 described LIDRS and postulated that the posterior movement of the iris resulted from thinly stretched zonules and an underdeveloped ciliary body. More recently, the term infusion deviation syndrome has been coined to describe this fluctuation in AC depth.1 This phenomenon results from a loss of vitreous volume, causing the liquefied vitreous to collapse after an initial incision (Figure 3, A). As irrigation is introduced, the iris diaphragm resting on the lens surface acts as a 1-way valve, trapping irrigation fluid in the AC and causing abnormal deepening (Figure 3, B). By lifting the iris away from the anterior lens capsule, the 1-way valve mechanism is broken, allowing irrigation to reach the posterior segment and restore volume in the vitreous cavity. As support from the vitreous is restored, the lens–iris diaphragm moves forward, and AC depth normalizes (Figure 3, C). A recent case report described a similar technique in a nonvitrectomized eye. In this case, contact between the anterior capsule and the iris associated with AC deepening was visualized with an intraocular endoscope.6
Eyes that have had extensive vitrectomy are at particular risk for developing intraoperative AC depth fluctuation. Myopic eyes and very elderly patients with synergetic vitreous are also at risk. We have found this simple maneuver to be a safe and efficient method to stabilize AC depth. Potential risks include trauma to the anterior capsule and iris. These can be avoided by using a short, blunt-ended second instrument and by avoiding excessive irritation of the iris. We have not encountered problems with capsule tear or excessive pupil miosis as a result of this maneuver.
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3. Díaz Lacalle V, Orbegozo Gárate FJ, Martinez Alday N, et al. Phacoemulsification cataract surgery in vitrectomized eyes. J Cataract Refract Surg 1998; 24:806-809
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5. Wilbrandt HR, Wilbrandt TH. Pathogenesis and management of the lens-iris diaphragm retropulsion syndrome during phacoemulsification. J Cataract Refract Surg 1994; 20:48-53
6. Cionni RJ, Barros MG, Osher RH. Management of lens-iris diaphragm retropulsion syndrome during phacoemulsification. J Cataract Refract Surg 2004; 30:953-956