It is generally believed that bilateral congenital cataracts should be removed by 8 weeks of age to achieve the best visual outcomes. Lambert and coworkers [22] evaluated the long-term visual outcomes for 43 children with dense bilateral congenital cataracts and found a linear relationship between the age of cataract surgery and the visual acuity in the better seeing eye (correlation coefficient = 0.28) (Fig. 18.3). They noted that delaying cataract surgery to 10 week of age or later increased the likely of a poor visual outcome (20/100 or worse). In contrast, Birch and coworkers [4] reported a bilinear relationship between the age of surgery and the visual outcome in 37 infants with dense bilateral congenital cataracts. Between birth and 14 weeks of age they noted a progressively worse visual outcome the older a child was at the time of cataract surgery (visual acuity decreased by 1 line with each 3 week delay in surgery). However, after age 14 weeks until 31 weeks, the visual outcome was independent of age at the time of cataract surgery (Fig. 18.4). These two studies suggest that unlike children with unilateral congenital cataracts, children with dense bilateral congenital cataracts do not have a well-defined latent period. However, other considerations such as the increased risk of glaucoma associated with very early cataract surgery and comorbidities should dictate the timing of cataract surgery.

The type of cataract has been reported to be a predictor of the visual outcome [34]. However, confounding variables make it difficult to ascertain the relative contribution of the type of cataract on the visual outcome. Certainly the density of lens opacities and the age of onset are important considerations. For example, eyes with partial cataracts that are acquired after birth (e.g. posterior lentiglobus and lamellar cataracts) are usually associated with better visual outcomes (Fig. 18.5) than cataracts associated with dense congenital opacities such as nuclear cataracts (Fig. 18.6) [30]. Cataracts arising from persistent fetal vasculature (PFV) have been reported to have a worse visual prognosis, but eyes with PFV vary greatly in their severity and some subtypes may be associated with good visual outcomes [31]. While personal photographs may allow the age of onset of cataracts to be ascertained in some instances [35], it is still difficult to ascertain the rate that cataracts progress using photographs alone.

Occlusion therapy is critical for the successful visual rehabilitation of children with a unilateral congenital cataract after cataract surgery. Selected children with bilateral congenital cataracts also require occlusion therapy after cataract surgery. Little is known about the best patching regimen to optimize visual acuity and binocular vision following unilateral congenital cataract surgery. Lambert and coworkers [23] reviewed the medical records of 9 children who underwent unilateral congenital cataract surgery when 6 weeks of age or younger. All of these children were compliant with patching therapy until 12 months of age and optical correction until 6 years of age. At age 12 months, the fellow eyes were patched a mean of 6.7 h/day. However, by 6 years of age, patching had declined to a mean of 1.7 h/day. Furthermore, 4 of the 9 children abandoned patching therapy entirely between the ages of 3 and 6 years. Nevertheless, visual acuity only worsened in one child after the cessation of patching therapy suggesting that visual acuity was not adversely affected by early termination of patching therapy provided the correct optical correction was being worn by the child.

Patching regimens for children with unilateral aphakia, unlike patching regimens for children with anisometropic and strabismic amblyopia [15, 25, 36], are not evidence based. However in recent years, there has been a trend to reduce the number of hours that patients are patched each day to potentiate the development of binocular vision in these children [18, 21]. Patching a child for longer than 6 h each day probably does not improve the visual outcome and may contribute to the loss of binocularity and contribute to the development of strabismus. This is illustrated by two case studies from my clinical practice. Both of these children underwent unilateral congenital cataract surgery during early infancy and both achieved 20/20 visual acuity in their aphakic eyes. However, Patient 1 had the fellow eye patched nearly full-time for 2 ½ years and now has no stereopsis and has required two strabismus surgeries to achieve satisfactory ocular alignment. In contrast, the fellow eye of Patient 2 was never patched for more than 6 h a day and patching was tapered beginning at age 14 months. These cases illustrate that good visual outcomes can be achieved with part-time patching. In addition, part-time patching may facilitate the development of binocular vision. Based on the excellent visual and stereopsis outcome achieved with the patching regimen for Patient 2, I now advise parents to only patch their child’s fellow eye for one-half of their waking hours until age 14 months. I then advise them to gradually reduce the frequency of patching until age 7 years when I recommend patching therapy be discontinued.

Nystagmus occurs commonly in children with bilateral congenital cataracts. If cataracts are left untreated, nystagmus usually develops between the ages of 10 and 12 weeks. Lambert and coworkers [22] reported that in children with bilateral congenital cataracts, preoperative nystagmus was a better predictor of a poor visual outcome than age at cataract surgery (Fig. 18.3). Only 38 % of children with preoperative nystagmus developed a best corrected visual acuity of 20/40 or better compared to 74 % of children with no preoperative nystagmus. Children with preoperative nystagmus underwent cataract surgery at a mean age of 18 weeks compared to 8 weeks for children undergoing cataract surgery without nystagmus. Young and coworkers [38] also found that nystagmus was a predictor of a worse visual outcome in children with bilateral congenital cataracts. However, they reported that most children developed nystagmus after cataract surgery, rather than before cataract surgery. While nystagmus can develop after cataract surgery, this is unusual. It is likely that the nystagmus was present preoperatively, but not documented since this was a retrospective chart review.

The type of optical correction worn probably does not affect the visual outcome in children with congenital cataracts provided the optical correction is worn on a consistent basis. However, compliance may be better with certain types of optical corrections than others. The Infant Aphakia Treatment Study found that children with a unilateral congenital cataract had similar visual outcomes at age 4 ½ years if an eye underwent primary IOL implantation or was left aphakic and corrected with a contact lens (Fig. 18.9) [17]. Birch and coworkers [3] also reported similar visual outcomes in children with dense unilateral cataracts after cataract extraction with or without IOL implantation when patients had good-to-excellent contact lens compliance. However, they reported worse visual outcomes in eyes left aphakic and treated with contact lenses when contact lens compliance was moderate-to-poor. Another case series reported similar visual outcomes in 15 children who underwent bilateral congenital cataract surgery coupled with primary IOL implantation compared to 18 children who underwent bilateral lensectomies and were initially optically corrected with contact lenses and only later underwent secondary IOL implantation [28]. Therefore the type of optical correction does not appear to be a major factor in determining the visual outcome if there is good to excellent compliance with the optical correction.