POSTERIOR CAPSULORRHEXIS TO PREVENT OR MANAGE IOL COMPLICATIONS

Howard V. Gimbel, MD, MPH and Hala Marzouk, MD

Posterior continuous curvilinear capsulorrhexis (PCCC) is a technique that uses the same principles that apply when creating an anterior continuous curvilinear capsulorrhexis (ACCC). PCCC may be planned to clear the visual axis, to prevent visual axis obstruction,¹ to use for PCCC optic capture,^2–4 or used to convert a small inadvertent linear or triangular posterior capsule tear into a continuous curvilinear tear to avoid an anticipated extension of the tear during such maneuvers as a required vitrectomy or lens placement.⁵ Openings in the posterior capsule may be made many years after primary surgery. This may be indicated when intraocular lens (IOL) removal and replacement or IOL repositioning is needed and membrane optic capture is planned to fixate the IOL by capsular membrane optic capture.²

Indications for Posterior Continuous Curvilinear Capsulorrhexis

TO PREVENT VISUAL AXIS OPACIFICATION IN CHILDREN

A major concern in pediatric IOL implantation surgery is the high incidence of posterior capsule opacification. Equatorial lens epithelial cells (LECs) proliferate, deposit on the posterior capsule, or deposit on the intact vitreous face if a vitrectomy has not been performed. This process can lead to secondary membranes that obscure the visual axis. The technique of PCCC and optic capture for pediatric eyes has been described by Gimbel and DeBroff^1,2 and Gimbel^3,4 to maintain a clear visual axis after pediatric cataract removal.¹ With certain IOL designs, PCCC optic capture has been shown to prevent posterior capsule opacification and maintain excellent IOL centration, even without vitrectomy, in children younger than 6 years. The technique may also be used after anterior vitrectomy in children to maintain a strong separation between anterior and posterior chambers (Video 20-1).

TO PREVENT POSTERIOR CAPSULE OPACIFICATION IN ADULTS

Posterior capsule opacification is considered the major cause of visual loss after cataract surgeries. The incidence is influenced by many factors such as patient age, surgical technique, underlying ocular disease, IOL material, IOL design, and IOL diameter. Recent improvements in surgical procedures and IOL technology have greatly reduced the incidence of after-cataract formation in adults. Thorough cortical clean-up, physical removal of remaining LECs within the lens bag, physical techniques to destroy LECs, and the use of antibodies against LECs have all been used and tried but posterior capsule opacification has not been eliminated when the posterior capsule remains intact. The only efficient treatment for established posterior capsule opacification is surgically induced rupture of the opaque posterior capsule (capsulotomy) using a capsulotomy needle or Nd:YAG laser.⁶ By preemptively opening the posterior capsule for some indications such as severe kyphosis and socioeconomic barriers to Nd:YAG laser capsulotomy, a clear visual axis would be permanently achieved. This has been suggested as a routine procedure along with posterior optic capture in some studies.7 An analysis of 1000 consecutive cases by Menapace showed no case of retrolental after-cataract formation after a minimum follow-up exceeding 3 years. The advantage of this technique is prevention of after-cataract independent of the optic edge design or material. He suggests considering optic capture as a routine in the following clinical situations: pseudoexfoliation syndrome because of the pronounced tendency of capsular shrinkage, high myopia because of the significantly greater inclination to develop after-cataract, and peripheral retinal pathologies requiring monitoring and treatment (myopia, diabetes) because of the need for an unimpeded view of the peripheral retina for monitoring, diagnosis, and therapy.⁸

TO MANAGE SMALL INTRAOPERATIVE POSTERIOR CAPSULE TEARS

In the case of a small preexisting or inadvertent tear of the posterior capsule during surgery, the tear may usually be converted into either a small, well-centered, circular PCCC or a PCCC just the right size to use for posterior capsule optic capture. A PCCC will be resistant to radial tears and prevents small triangular, linear, or flap tears from extending to the equator. The PCCC thereby stabilizes the capsular bag, especially during subsequent IOL implantation or vitrectomy. Haptics in the bag or behind the CCC are essential for single-piece IOLs with haptics too thick for sulcus placement and ACCC capture. If a PCCC cannot be obtained and the lens is not in the bag yet, the lens may be placed in the sulcus and the haptics then maneuvered through the CCC into the posterior chamber for reverse CCC optic capture (Figure 20-1 and Video 20-2).

TO REMOVE A POSTERIOR CAPSULAR PLAQUE

Primary posterior capsule opacification might be discovered during surgery. This will decrease the visual acuity and contrast sensitivity with resulting glare. Primary PCCC may be performed to remove the opacified posterior capsule after polishing has failed as an intraoperative intervention. Alternatively, the surgeon might consider performing an early Nd:YAG capsulotomy (Video 20-3).

TO GAIN ACCESS TO THE VITREOUS CAVITY

PCCC might also be required for a number of indications such as the removal of silicone oil, reduction of asteroid hyalosis, and for anterior vitrectomy and antibiotic injection in cases of presumed postoperative endophthalmitis. PCCC optic capture may be considered in these situations where the posterior capsule has been opened.

TO MANAGE LATE POSTOPERATIVE COMPLICATIONS

PCCC in capsular membranes may be used to achieve secure IOL fixation and centration. Examples are:

• When repositioning IOLs that may be decentered because one haptic is not in the bag and the bag is now a membrane.
  
• When stabilizing loose sulcus IOLs that are decentered or causing uveitis-glaucoma-hyphema syndrome and the posterior capsule has not been opened or the opening is not large enough for membrane optic capture.
  
• When replacing an IOL and in-bag replacement is not possible because of fibrosis between the anterior and posterior capsule except for the channels out of which the haptics have been removed (Video 20-4).

TO STABILIZE SECONDARY IOLS PLACED IN THE CILIARY SULCUS

IOLs are not always placed at the time of cataract surgery as in infantile cataract surgery. IOL implantation in the bag later in life is usually not possible. At times, especially in children, a thick Soemmering ring may be opened for placing haptics in the bag.

PCCC in the capsular membrane may be performed to use for membrane optic capture. And if an opening in the membrane is not large enough to use for capture, it may be further enlarged for optic capture if enough fibrosis exists on the capsule (Videos 20-5A and B).

Technique in Primary Surgery

1. Following phacoemulsification, PCCC can be done before or after IOL implantation. Select the optimal ophthalmic viscosurgical device (OVD) for the specific case. Cohesive, high molecular weight OVDs provide optimal flattening of the lens capsule and are better at chamber maintenance than are dispersive, low molecular weight OVDs. The PCCC is initiated using a vitrector, a cystotome, or a bent needle. In infants, DeBroff and Nihalani found the technique of performing the posterior capsulotomy with the vitrector handpiece technically less difficult than performing a PCCC with forceps. It can offer a tear-resistant edge in infantile eyes that is amenable to optic capture. They then use double optic capture through both the ACCC and PCCC to secure the IOL.⁹
   

   If one wishes to avoid a vitrectomy and leave the vitreous undisturbed, a small central opening is first made in the posterior capsule. It is preferable to start the PCCC with a hooking snag motion rather than a stabbing puncture. A small snag may be created using the barbed end of a disposable 27-gauge hypodermic needle. This small barb may be made by pressing the tip of the needle against the handle of a needle driver or forceps until a very small, right-angle bend is made in the tip.

   
   
2. Next, the vitreous is pushed back by injecting additional cohesive OVD through the opening into Berger’s space. In doing so, the tear is guided away from the center in a direction that will enable the surgeon to easily grasp the developing flap with the forceps.
   
3. The elevated edge of the incised capsule is then grasped by Kraff-Utrata capsulorrhexis forceps or other microforceps and the tearing is continued in a curvilinear, circular manner until complete. The flap should be reengaged a number of times to control the direction of the tear. Additional viscoelastic is added intermittently to always keep OVD underneath the area where the flap of capsule is being regrasped. The more difficulty there is in controlling the direction of the curvilinear tear, the more frequently the flap must be released and regrasped. Each time the flap is released, be sure to elevate the flap edge in order to make it easier to regrasp the flap again.

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