Intraocular lenses in children: changes in axial length, corneal curvature, and refraction

Abstract

Aim-To assess changes in axial length, corneal curvature, and refraction in paediatric pseudophakia. Methods-35 eyes of 24 patients with congenital or developmental lens opacities underwent extracapsular cataract extraction and posterior chamber intraocular lens implantation. Serial measurements were made of axial length, corneal curvature, objective refraction, and visual acuity. Results-For patients with congenital cataracts (onset <1 year age) the mean age at surgery was 24 weeks. Over the mean follow up period of 2.7 years, the mean increase in axial length of 3.41 mm was not significantly diVerent from the value of an expected mean growth of 3.44 mm (paired t test, p=0.97) after correction for gestational age. In the developmental cataract group (onset >1 year of age) the mean age at surgery was 6. Conclusion-The pattern of axial elongation and corneal flattening was similar in the congenital and developmental groups to that observed in normal eyes. No significant retardation or acceleration of axial growth was found in the eyes implanted with IOLs compared with normal eyes. A myopic shift was seen particularly in eyes operated on at 4-8 weeks of age and it is recommended that these eyes are made 6 D hypermetropic initially with the residual refractive error being corrected with spectacles. (Br J Ophthalmol 1999;83:265-269) Among the problems which arise regarding the use of intraocular lenses (IOLs) in the paediatric population is the question of the power of the implant that should be used, considering the expected growth of the child's eye. The majority of eye growth takes place in the first 18 months of life after which there is little change.

Paediatric intraocular lens implants: accuracy of lens power calculations

“…9 In paediatric patients it is common to aim, not for emmetropia, but for a degree of hypermetropia that takes into account the expected emmetropisation with age and the degree of anisometropia that will occur relative to the refractive state of the fellow eye. Children undergoing surgery in our study had their refractive outcome matched for age in keeping with the findings of Flitcroft et al 27 Infants less than 12 months of age had a refractive goal of +6 D, decreasing to +3 D at 3 years of age and emmetropia at 8 years of age. Given that the prediction formulae are usually used and originally designed to aim for emmetropia (or close to it), it is possible that they are less accurately applicable to the higher refractive goals employed in paediatric cataract surgery.…”

Clinical and experimental advances in congenital and paediatric cataracts

“…Most surgeons choose an IOL that leaves the infant hypermetropic (approx. þ8 D at six weeks of age, þ3 D at 12 months, þ2 D at 2 years) to allow the eye to 'grow into the IOL', correcting the resulting ammetropia with spectacles [11,19]. The requirement of accommodation for near tasks should be considered for each age group.…”

Changing refractive outcomes with increasing astigmatism at longer-term follow-up for infant cataract surgery

“…[4][5][6][7][8][9] The critical message from our study is that there is a rapid change in refraction in the first 2 years that declines over the following 2 years and tends to stabilize by age 4 years. This implies that frequent refraction and change of glasses/contact lenses are needed in the first 2 years, followed by regular checks (at least 6 monthly) from age 2 to 4 years.…”