Novel Technique of Pneumatic Posterior Capsulorhexis for Treatment and Prevention of Posterior Capsular Opacification
Condition: Posterior Capsule Opacification
MeSH terms: Capsule Opacification
Study type: Interventional

Summary: 
      ABSTRACT PURPOSE: To evaluate a new technique of posterior capsulorhexis using air support to
      treat primary posterior capsular opacification (PCO) during cataract extraction surgery or to
      prevent post-operative PCO.

      SETTING: 1-Ophthalmology department, Faculty of medicine, Minia University, El-Minia, Egypt.

      2- Security Forces Hospital, Ophthalmology Department, Riyadh, Kingdom of Saudi Arabia.

      DESIGN: Prospective, randomized case-control comparative study.

      Methods: 100 eyes of 100 patients with a mean age of 63.3 years with dens cataract. Fifty of
      them ( group 1) with primary PCO (discovered during the operations) and fifty (group 2) with
      clear posterior capsule.

      All cases undergone phacoemulsification, posterior capsulorhexis using the air to support the
      posterior capsule and separate it from the vitreous (the novel technique will be discussed
      later). Then IOL implantations wear done in the bag between the anterior and posterior
      capsular rim. Each patient was evaluated for the following:- visual acuity (UCVA and BCVA),
      intraocular pressure, intra ocular lens stability, visual axis opacification and posterior
      segment complications as retinal break, retinal detachment or cystoid macular oedema.
    

Detailed description: 
      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.

      Patients and methods:

      Indications of the new technique

        1. Intraoperative PCO in white cataract.

        2. As a primary procedure during cataract extraction to prevent post-operative PCO. Thirty
           eyes of 100 patients with dens cataract were chosen from the outpatient clinic of the
           ophthalmology department, Minia University Hospital, El-Minia Egypt. The patient's age
           ranged from 50-73 years with a mean age of 63.3 years 50 males and 50 females without
           any local or systemic causes for the cataract. The study group included fifty eyes
           (group1) with PCO, and fifty eyes (group 2) with clear posterior capsule (discovered
           intra-operative). All cases were subjected to complete ophthalmic examinations and
           echographic data registration. All cases undergone Phacoemulsification, posterior
           capsulorhexis using the air to support the posterior capsule and separate it from the
           vitreous face. Table (1)

      The novel technique:

      After complete phacoemulsification of the nucleus and I/A:

        1. Visco-elastic material was injected to make the anterior chamber formed without
           deepening so that the posterior capsule is not forcibly pushed backward.

        2. The posterior capsule punctured centrally using cysteotome Fig. (1).

        3. Controllable one shot injection of 0.1 ml of sterile air through the posterior capsule
           puncture which elevate, support and separate the posterior capsule from vitreous face.
           (Insulin syringe and Helon cannula were used) Fig. (2).

        4. Another visco-elastic injection to the anterior chamber to stretch the posterior capsule
           and sandwitich it between visco-elastic above and the air below Fig. (3).

        5. Posterior capsulorhexis 4-5 mm is now performed easily using capsulorhexis forceps then
           foldable IOL was implanted between the anterior and posterior capsular rim .
    

Intervention name(s): Pneumatic Posterior Capsulorhexis
Intervention type(s): Procedure
Intervention description(s): Pneumatic Posterior Capsulorhexis using air dose 0.1 ml and Healon dose 0.5 -1.0 ml.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: PCO