There are a number of postoperative syndromes that can occur with the Crystalens accommodating IOL because of its unique hinged haptic design. These must be distinguished by carefully assessing the vault of the lens and the appearance of the capsule so that the etiology of the malposition can be determined and the appropriate treatment instituted (i.e., selective laser capsulotomies versus lens rotation/repositioning with or without the insertion of a capsular tension ring). Drs. Harvey Carter (http://www.bauschlocal.com/ascrs/archive/presentations/carter.html), Jack Singer, and Jay Pepose, and others have presented detailed explanations of these techniques, which I summarize below.
Capsular contraction syndromes
Capsular contraction occurs after cataract surgery with all IOLs due to fibrosis. It may cause a change in refractive outcome, particularly with an accommodating lens (i.e., Baush + Lomb Crystalens). When this happens, selective Nd:YAG laser capsulotomy is performed to restore the capsular diameter and return the lens to its proper position. Care must be taken to avoid large incisions past the lens edges to prevent vitreous prolapse around the lens.
Anterior capsular contraction syndrome (ACCS):
the anterior capsule becomes opaque from fibrosis and pushes the IOL optic posteriorly causing excessive vaulting and a hyperopic shift with reduced accommodative amplitude. Treatment is by creating small relaxing YAG laser incisions on the anterior capsular rim on both sides of the IOL optic away from the hinges.
Posterior capsular contraction syndrome (PCCS):
With lens tilt (one haptic is planar and the other is vaulted anteriorly or posteriorly) results in a myopic shift with little or no astigmatism. Treatment is by creating a small oval posterior capsulotomy behind the more anteriorly vaulted haptic between the hinge and insertion of the haptic loops, and by lysing any fibrotic bands under the haptic allowing that haptic to move posteriorly. A separate central round opening behind the optic may also be necessary.
With Z-syndrome (one haptic is vaulted posteriorly and the other is vaulted anteriorly) results in a myopic shift with astigmatism along the long meridian of the lens. Treatment is by creating up to 3 selective posterior capsulotomies: first a small oval opening behind the anteriorly vaulted haptic (as described above); if not effective then second, a central round capsulotomy behind the optic (as described above); and if not effective then third, a small oval opening behind the posteriorly vaulted haptic (similar to that behind the anteriorly vaulted haptic).
Posterior capsular opacification, which commonly occurs as well, results in decreased vision and is treated with a central round posterior capsulotomy that does not extend beyond the edge of the optic.
Techniques to minimize contraction syndromes include creating a 5.0-5.5 mm round well-centered capsulorhexis, polishing the posterior capsule and the undersurface of the anterior capsular edge, symmetric haptic placement in the bag, rotating and rocking the lens to ensure correct haptic positioning.
Hyperinflation syndrome
An excessively posteriorly vaulted lens with both haptics stuck in the posterior capsule resulting in a hyperopic shift due to overinflation of the anterior chamber at the conclusion of surgery. This condition is not treated with selective YAG laser capsulotomy but rather with IOL repositioning by rotating the lens 90 degrees and making sure not to overinflate the eye with BSS.
Deflation syndrome
An anteriorly vaulted lens resulting in a myopic shift during the first 2 weeks after surgery due to wound leak. If the shift is <1 D then cycloplegia may restore the lens to the correct position, otherwise repositioning the lens and ensuring a watertight wound is necessary.