Contact Lenses

Contact lenses have been the preferred means of optically correcting aphakia in infants because they more closely simulate the optics of the crystalline lens than do spectacles. During the first 4 years of life, an aphakic infantile eye undergoes a mean decrease in its refractive error of 9-15 D [27,33]. Therefore, the ability to easily change the power of a CL as refractive needs change is a significant advantage. Excellent visual acuities have been obtained in infants with bilateral aphakia using CLs, with up to two-thirds of these children achieving 20/40 or better visual acuity in at least one eye [11,29]. Contact lens compliance is usually good for children with bilateral aphakia and if they become CL intolerant, they can be treated with spectacles.

The treatment of monocular aphakia during infancy with CLs has been less successful. In published series, only 8-24% of these eyes achieved 20/40 or better visual acuity and the majority saw 20/200 or worse [29, 34]. These poor visual outcomes largely arise from poor CL and patching compliance. The poor visual acuity in the aphakic eye then makes it more difficult to patch the fellow eye, which then causes further visual deterioration. Ultimately, many parents abandon patching and CL treatment for their child due to the difficulty and time demands of this treatment regimen. Assaf and co-workers [2] reported that only 44% of children with unilateral aphakia were wearing their CL when they returned for follow-up. Poor compliance in these patients is multifactorial but lens loss, difficulty inserting and removing CLs in a small child, and the absence of a discernible visual benefit - since the fellow eye has normal vision - all contribute to poor CL compliance. The resulting poor vision in the aphakic eye then creates a number of problems. First, there is a greater risk of the normal eye being injured [38]. Second, if their fellow eye becomes blind secondary to injury or disease later in life they do not have a back-up eye with useful vision. Lastly, many of these patients develop a sensory strabismus, which often must be corrected surgically.

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