Optical Considerations in Aphakia and Pseudophakia
Mae Millicent W. Peterseim, MD
Rupal H. Trivedi, MD, MSCR
Aphakia following cataract extraction in children may be corrected with spectacles, contact lenses (CTL), IOLs, and combinations of each. The initial surgical decision includes consideration of methods to best obtain optical correction both immediately postoperatively and as refractive needs change with growth. The extreme hyperopia of uncorrected aphakia or pseudophakia is devastatingly amblyogenic, making optical correction and amblyopia treatment imperative for the development of useful vision.
IOL implantation in children has the benefit of reducing dependency on compliance with other external optical devices (aphakic glasses and CTL) while providing at least a partial optical correction. These are important advantages to the visual development in amblyopia-prone eyes. However, concerns about primary IOL implantation in very young children include the technical difficulties of IOL implantation in small eyes, selection of the appropriate IOL power, and a higher risk of postoperative complications. While IOL use is becoming more widespread, relative contraindications to IOL implantation may include <6 months of age, severe microphthalmia, ectopia lentis, uveitis, and surgeon or parental preference.
The optical needs of the pediatric eye are expected to change with growth. Frequent follow-up and refraction update are essential, regardless of the choice for aphakic correction. This chapter provides considerations in optical correction in pediatric aphakia and pseudophakia.
APHAKIC SPECTACLES
Option for infants with bilateral cataracts.
Not desirable for monocular correction due to retinal size disparity.
Create distortion—up to 30% magnification.
Safe and easily adjusted.
Require patient compliance.
Heavy with poor cosmetic appearance.
Experienced optician should determine the smallest lens and optic size that can reduce the central thickness and weight of the lens.
Follow-up: Measure for change in refraction over glasses considering vertex distance.
In infants and toddlers, it is satisfactory to use single vision lenses overplussed to focus at near (see below for details).
As children age 2-3 years old become more interested in distance tasks, they should be prescribed their full cycloplegic refraction for distance with a +3 bifocal.
CONTACT LENS
Recommended for unilateral aphakia, especially in young children.
Creates 5%-9% magnification.
Decreases aniseikonia in monocular cases compared with spectacles.
Cost can be a limiting factor due to frequent replacement.
Requires caretaker care.
Risks include infection and corneal vascularity.
May be a temporary solution until secondary IOL implantation.
Types of CTL:
Hard lenses—rigid gas permeable (RGP):
Good choice for the smallest eyes.
Correct astigmatism and maintain shape.
Allow precise correction.
Require daily care.
Hydrogel:
For older children.
May be daily wear, disposable.
Scleral lenses:
For surface abnormalities unable to be fitted with conventional lenses (eg, corneal laceration with secondary scarring).
Silicone (Silsoft):
Most widely used and well tolerated in infants.
Mask 2 D astigmatism.
Resist absorption of topical ophthalmic drugs.
Extended wear is possible, however, increased risk of severe complications (infection and corneal vascularization). Recommendation is for weekly removal and cleaning.
Relative ease of insertion and removal.
Options:
Super Plus series: diameter 11.3 mm; BC 7.5, 7.7, and 7.9; power +23 D to +32 D in 3-D steps. Most aphakic infants are initially fitted with lenses that have a base curve of 7.5 mm.
Bausch & Lomb Patient Assistance Program SilSoft SuperPlus.
Aphakic series: diameter 11.3 or 12.5 mm; BC 7.5, 7.7, 7.9, 8.1, or 8.3; power +12 D to +20 D in 1-D steps.
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