Management of the Anterior Lens Capsule in Pediatric C ataract Surgery

Suqin Guo, MD · Rudolph S. Wagner, MD

Introduction

Cataract extraction with intraocular lens (IOL) implantation is a commonly used surgical procedure to manage pediatric cataracts. The anterior lens capsulotomy/capsulectomy is a critical surgical step of modern cataract extraction and IOL implantation surgery. Can-opener capsulotomy, used in large incision extracapsular cataract extraction, is prone to the occurrence of radial tears, as well as unwanted surgical complications including vitreous loss.1 A continuous curvilinear capsulorrhexis is smooth and resistant to radial tears during modern cataract surgery.2 The integrity of the anterior capsular opening (capsulectomy/capsulotomy) is critical for not only reducing intraoperative complications like vitreous loss, but also to ensure long-term stable centration of IOLs. 3-5 Therefore, continuous curvilinear capsulorrhexis (CCC) has become a standard procedure in the management of cataracts in adults and children.6,7

Approaches in Managing Anterior Capsule in Pediatric Cataract Surgery

A manual CCC is more difficult in young children than in adults because the child's lens capsule is elastic and requires more force to tear.6,8 The incidence of radial tears of the lens capsule and extension of the tears to the lens equator are proportional to the force to generate the capsulorrhexis.6 The force required in a manual pediatric CCC significantly increases the incidence of radial tears in these young eyes.

In another study of 153 children with retinoblastoma from Brazil, 80 (52%) patients received treatment within 6 months of symptom onset (early diagnosis) and 73 (48%) received treatment more than 6 months after symptom onset (late diagnosis). The 3-year survival rate was 82% in the early diagnosis group compared with 44% in the late diagnosis group. The worse prognosis in the late diagnosis group correlated with the tendency of patients in this group to exhibit extraocular extension of the retinoblastoma.22,23

To minimize the difficulty of manual anterior CCC in pediatric eyes, various surgical approaches have been studied. Wilson and colleagues pioneered anterior vitrectorhexis (mechanized capsulectomy) as an alternative approach compared to other types of cataract surgery.6 They compared mechanized capsulorrhexis with manual CCC using 18 pairs of postmortem pediatric eyes. They concluded that mechanized CCC gives surgeons an alternative in pediatric eyes in which standard CCC may be difficult to perform.6 Wilson and colleagues also applied the anterior vitrectorhexis technique to 20 pediatric eyes. Radial tears of the anterior lens capsule occurred in 15% of eyes.7

Radiofrequency diathermy capsulotomy has been studied as an alternative technique to be used in mature cataracts.9-11 Comer and colleagues reported radiofrequency diathermy anterior capsulorrhexis in 14 pediatric eyes with good results.11 Radiofrequency diathermy may have advantages over manual CCC in mature cataracts or in eyes with small pupil.10,11 Disadvantages of this technique include common longitudinal tears of the capsulorrhexis edge and an increased vulnerability to radial tears during surgical manipulation.11

Indocyanine green (ICG) staining of the anterior capsule was first described by Horiguchi and colleagues.12 The technique was reported to facilitate performance of the CCC in eyes with mature cataract. My colleagues and I have written about our consistent, successful experience with ICG staining-assisted anterior capsulorrhexis in pediatric cataract and intraocular surgery.13

Experience in Management of Anterior Lens Capsule in Children

Slide 1

Slide 1.A manual continuous curvilinear capsulorrhexis can be easily accomplished by applying a vector force toward the center of the pupil and regrasping the capsule flap more frequently.
Manual CCC provides a smooth edge that is resistant to radial tears. It is a standard in pediatric cataract surgery in our practice. To minimize difficulty of performing manual CCC in pediatric eyes we maintain high magnification under the operative microscope and use viscoelastics liberally.14 A manual CCC is more easily accomplished by applying a vector force toward the center of the pupil and by starting the capsular tear 1 mm to 2 mm smaller than the target size in pediatric eyes.15 Radial tears of manual CCC can be minimized by grasping the capsular flap frequently during the procedure (Slide 1).

Slide 2

Slide 2. After indocyanine green stain is placed under the air bubble, the air is exchanged with viscoelastic.
Not only is ICG staining-assisted capsulorrhexis useful in adult cataract surgery, but it is also a useful technique in pediatric cataract surgery, as well. The visualization of the anterior lens capsule can be significantly enhanced, making the manual CCC much easier to perform than other types of cataract surgeries. Radial tears of the lens capsule can be significantly reduced with this technique. The ICG is placed onto the anterior lens capsule with a 30-gauge cannula after a large air bubble is injected into the anterior chamber (Slide 2). The air is then exchanged with viscoelastics. Once ICG capsular staining is finished, the standard cataract surgery can be completed.

References

  1. Wasserman D, Apple DJ, Castanda VE. Anterior capsular tears and loop fixation of posterior chamber intraocular lenses. Ophthalmology. 1991;98:425-431.
  2. Assia EI, Apple DJ, Barden A, et al. An experimental study comparing various anterior capsulotomy techniques. Arch Ophthalmol. 1991;109:642-647.
  3. Assia EI, Apple DJ, Tsai JC, et al. Mechanism of radial tear formation and extension after anterior capsulectomy. Ophthalmology. 1991;98:432-437.
  4. Assia EI, Apple DJ, Tsai JC, et al. The elastic properties of the lens capsule in capsulorhexis. Am J Ophthalmol. 1991;111:628-632.
  5. Assia EI, Legler UFC, Merrill C, et al. Clinic pathologic study of the effect of radial tears and loop fixation on intraocular lens decentration. Ophthalmology. 1993;100:153-158.
  6. Wilson ME, Bluestein EC, Wang X, et al. Comparison of mechanized anterior capsulectomy and manual continuous capsulorhexis in pediatric eyes. J Cataract Refract Surg. 1994;20:602-606.
  7. Wilson ME, Saunders RA, Roberts EL, et al. Mechanized anterior capsulectomy as an alternative to manual capsulorhexis in children undergoing intraocular lens implantation. J Pediatr Ophthalmol Strabismus. 1996;33:237-240.
  8. Gimbel HV, Ferensowicy M, Raanan M, et al. Implantation in children. J Pediatr Ophthalmol Strabismus. 1993;30:69-79.
  9. Morgan JE, Ellingham RB, Young RD, et al. Mechanical properties of the human lens capsule following capsulorhexis or radiofrequency diathermy capsulotomy. Arch Ophthalmol. 1996;114:1110-1115.
  10. Gassmann F, Schimmelpfennig B, Kloti R. Anterior capsulotomy by means of bipolar radio-frequency endodiathermy. J Cataract Refract Surg. 1998;14:673-676.
  11. Comer RM, Abdulla N, O'Keefe M. Radiofrequency diathermy capsulorhexis of the anterior and posterior capsule in pediatric cataract surgery: Preliminary results. J Cataract Refract Surg. 1997;23:641-644.
  12. Horiguchi M, Miyakek K, Ohta I, et al. Staining of the lens capsule for circular continuous capsulorhexis in eye with white cataract. Arch Ophthalmol. 1998;116(4):533-537.
  13. Guo S, Caputo A, Wagner R, et al. Indocyanine green staining capsulorhexis in pediatric white cataract. The American Association for Pediatric Ophthalmology & Strabismus. Annual Meeting (Abstr). 2000;71.
  14. Gimbel HV, DeBroff BM. Posterior capsulorhexis with optic capture: Maintaining a clear visual axis after pediatric cataract surgery. J Cataract Refract Surg. 1994;20:658-664.
  15. Anderson LK, Wilson E, Apple D. Elastic properties and scanning electron microscopic appearance of manual continuous curvilinear capsulorhexis and vitrectorhexis in an animal model of pediatric cataract. J Cataract Refract Surg. 1999;25:534-538.