Novel Technique of Pneumatic Posterior Capsulorhexis for Treatment and Prevention of Posterior Capsular Opacification

Introduction. Posterior capsular opacification (PCO) is one of the common late post-operative complications of phacoemulsification and ECCE. The treatment of PCO by YAG laser capsulotomy usually leads to the famous annoying symptom (musca) and carries the risk of IOP elevation. Moreover, it may lead to the posterior segment complications ( cystoid macular edema, retinal breaks and detachment). There is no reliable treatment for prevention of PCO.

The current available modalities to prevent postoperative PCO are:

• Some surgical modifications as hydrodissection, repeated nucleus rotation and meticulous polishing of the lens epithelial cells (LECs) from anterior capsular rim and equator. In 1989 David Apple and his group (1) had demonstrated the value of hydrodissection. In 1992, they further emphasized hydrodissection as well as barriers to migration of equatorial cells to the posterior capsule as methods which could reduce PCO (2). In the same year Fine described a technique which he termed 'cortical cleaving hydrodissection', (3) which was designed to break the equatorial adhesions between lens epithelial cells and the capsule, thus increasing the chance of significant clearance of these cells which are the progenitors of PCO. In 2006 they pointed out to the laboratory and clinical evidence that good hydrodissection, coupled with mechanical 'scouring' of LECs from the equator may have beneficial effect on decreasing PCO incidence. (4,5). In a laboratory experiment they found that there were significantly fewer cells remaining in the capsule equator in the group of eyes where the lens had been rotated three times within the bag prior to removal, compared with no such rotation(4).
• Changes in the IOL design and materials: e.g. The square edge of the optic and acrylic IOL decreases the incidence of postoperative PCO than with PMMA IOLs of similar design.
• Pharmacological strategies either to kill the residual epithelial cells or to prevent their post operative proliferation. The pharmacological prevention has been largely unsuccessful so far. Moreover, any agent must be toxic to these epithelial cells without being toxic to the corneal endothelium. Few agents have been partially successful without clinical application till now (6).

The incidence of PCO following successful cataract surgery has been falling since the general acceptance of posterior chamber in-the-bag intraocular lens (IOL) implantation. Improvement in lens materials, lens design and technique are well documented to decrease the incidence of postoperative PCO (8, 9). Rotation three times of the hydrodissected nucleus prior to phacoemulsification and a second hydrodissection after nucleus removal are simple and safe maneuvers that statistically improve the results (9). Bimanual irrigation/aspiration may also help.(10) Treatment options for PCO

• YAG laser posterior capsulotomy
• Surgical posterior capsulotomy or capsulectomy
• Primary (Intra-operative)
• Secondary.