After 1 year without clinical difficulty and in the absence of evidence of recurrent instability, the most likely etiology is minimal longstanding IOL tilt combined with an episode of “reverse pupillary block” that caused the iris to bow posteriorly. The remedy should, therefore, be the least invasive maneuver that relieves the problem and prevents recurrence. In addition to the unsatisfactory optics of the half-captured IOL, this scenario usually results in chronic low-grade inflammation and intervention is mandatory.
Occasionally, the optic can be “popped” behind the pupil by an abrupt forceful push with a cotton-tip applicator on the anesthetized cornea. If this fails, the next maneuver is wide dilation to determine whether the optic repositions itself, either spontaneously or with transscleral pressure by a cotton swab over the haptics near the suture fixation site.
If those office maneuvers fail, the patient should be taken to the operating room and the IOL optic reposited by an instrument placed through a paracentesis. The surgeon must be prepared for more aggressive intervention, such as resuturing or an IOL exchange, if the IOL is unstable or more severely malpositioned at that time. Most likely, that will not be the case. I would then place an iridoplasty suture of 10-0 polypropylene using the slipknot technique first described by Siepser1 to minimize the risk for later recapture.
In addition, whether the problem is relieved in the office or in the operating room, I would place a peripheral iridectomy (surgical or laser) to prevent another episode of reverse pupillary block, which may have been the cause of the optic capture.
1. Siepser SB. The closed chamber slipping suture for iris repair. Ann Ophthalmol 1994; 26:71-72