[Cataract surgery in children].

INTRODUCTION

Cataract extraction in children has improved and became more popular over the past few decades but, due to particular features of children's eyes, still remains controversial--especially regarding the intraocular lens implantation.

INDICATIONS FOR OPERATION

In contrast to adults, indications for cataract surgery in children are much more difficult to determine. Since subjective visual acuity cannot be obtained, greater reliance must be placed on the morphology and location of the lens opacity, and the behavior of the child. Forced preferential looking and visual evoked potentials can be helpful, but they should not be the only criteria.

CORRECTION OF POSTOPERATIVE APHAKIA

In management of pediatric cataract, correction of postoperative aphakia is still an incompletely resolved problem. Conventionally, optical correction is achieved by spectacles or contact lenses. The power of both spectacles and contact lenses can be readily adjusted to compensate for ocular growth. The success of both depends significantly on parental compliance and the child's acceptance. Hutchinson reported that 44% children with aphakia stopped wearing glasses or contact lenses 2 months after surgery. Contact lens wearing can also result in a number of corneal complications, including infectious keratitis, corneal vascularization and hypoxic corneal ulceration. IOL implantation is theoretically superior to glasses and contact lenses since it provides almost immediate optical correction which is much more reliable because it does not depend on parental or child's compliance. Still, there are many controversies about IOL implantation in infants and young children like IOL-size, material, IOL power calculation, prevention and management of secondary cataract, as well as long term safety of IOLs in children's eyes. Although short-term anatomic results after cataract extraction and primary IOL implantation in children are excellent and stable, long-term follow-up is necessary to answer questions about the long-term safety of implants in children's eyes.

POSTOPERATIVE COMPLICATIONS

A higher incidence of postoperative inflammation and opacification of the optical axis has been reported after pediatric cataract surgery. Posterior capsular opacification is almost an unavoidable complication in children's eyes if the posterior capsule is left intact. Several methods have been proposed in order to keep the optical axis clear in infants and young children. Comparison of posterior capsulectomy with and without anterior vitrectomy showed that posterior capsular opacification rates are diminished only after combined posterior capsulectomy and anterior vitrectomy and not after capsulectomy alone. Posterior capsulorhexis with optic capture seems to effectively prevent posterior capsular opacification. This technique eliminates the need for anterior vitrectomy and ensures the centration of the intraocular lens. Glaucoma and retinal detachment are late complications of pediatric cataract surgery. On average glaucoma develops 6.8 years after cataract operation. Retinal detachment develops several decades after cataract extraction.

AMBLYOPIA

The functional results after pediatric cataract surgery depend not only on the anatomic success of the operation and postoperative maintenance of a clear optical axis, but even more on aphakic visual rehabilitation. Children's eyes with cataract severe enough to require cataract extraction usually have some degree of amblyopia already present prior to surgery. In unilateral pseudophakia amblyopia develops postoperatively unless the fellow eye is occluded or optically and/or pharmacologically penalized. Immediate optical correction is desirable because prevention and/or therapy of amblyopia should be initiated directly after surgery. Parental compliance with occlusion therapy and not successful surgery are major determinants of a good visual outcome in unilateral aphakic/pseudophakic children.