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For aphakic children younger than two, contact lenses are the primary choice for vision correction.1-3 Unfortunately, no perfect lens modality exists for this therapy. Soft lenses such as Silsoft (Bausch + Lomb) are usually the top choice due to ease of fitting and high Dk material; however, these high plus lenses are only available in limited sizes and 3D changes in power, which does not allow for precision fitting. They can also soil, and replacements are expensive.
Some practitioners choose to fit custom soft lenses to control the lens parameters, but these are generally low Dk and have a higher risk of hypoxia.4 Others choose gas permeable (GP) lenses because of the premium optics, ease of handling, simple retinoscopy abilities and verification ability. However, these can be a challenge to fit.
These complications often force practitioners to get creative with their lens choices and remain flexible throughout the child’s development. A younger child might be less sensitive to blurry vision compared with a teenager who may be ready to drive. Poor vision can also impact a child’s learning, and it is our job to make their vision as clear as possible to allow them to succeed in school. This case highlights one of the common challenges associated with switching a soft lens aphakic patient to GPs: comfort.
The Case
A 16-year-old female presented with history of bilateral aphakia and a primary complaint that her vision with her contact lenses was blurry and inconsistent. Her cataracts were removed in infancy, and she had a history of neovascularization with low Dk soft lenses.
She wore MetroSoft Definitive (MetroOptics) soft contact lenses at 8.6/+19.00/15.0 OD, 8.6/+20.00/15.0 OS. Her presenting visual acuity was 20/25- OD, 20/30- OS.
The patient’s pupils were slightly decentered and peaked, but they were still reactive to light with no relative afferent pupillary defect in either eye. Extraocular movements were full OU. A slit lamp exam revealed clear lashes and corneas OU and deep and quiet anterior chambers OU. Aphakia was noted in both eyes. Her intraocular pressure was 15mm Hg OU. Keratometry readings showed 45.00/46.00@045 OD and 44.00/44.50@150 OS. Undilated posterior segment evaluation revealed normal fundus OU.
Contact Lens Evaluation
Both soft lenses were centered with adequate movement. Over-refraction revealed:
- Plano +1.50x133 (VA of 20/20) OD
- -0.75 +1.75x060 (VA of 20/20) OS
I discussed lens options with the patient and her mother. GP lenses would offer the best vision but would require adaptation. Soft toric lenses may be more comfortable with less consistent vision. The patient was resistant to the idea of rigid lenses and opted for soft toric lenses. The following MetroSoft Definitive lenses were ordered:
- 8.6/+20.50-1.50x 043/15.0 OD
- 8.6/+21.00-1.00x165/15.0 OS
Soft Lens Dispensing Visit
The patient presented two weeks later with no new complaints. I placed the lenses on her eyes and allowed them to settle. On slit lamp examination, the lenses were well centered with adequate movement and toric markers at 6 o’clock. Visual acuities were 20/25- OD, 20/30 OS.
At this point, the patient reported that her vision fluctuated with each blink, and over-refraction did not improve vision OU. The patient’s mother asked to try rigid lenses in office. I then placed diagnostic GP lenses of the following parameters on the patient’s eyes:
- 7.90/ +15.00/9.8 OR: +3.00 20/20 OD
- 8.0/+15.00/9.8 OR: +2.00 20/20 OS
A spherical over-refraction brought the patient’s vision to 20/20 OU. She was still resistant to GP wear, however. She said the lenses were uncomfortable and she wouldn’t wear them. We discussed the adaptation period and I informed the patient that if she could not get used to the lenses, we could use soft lenses to piggyback for comfort. With much persuasion from her mother, the patient agreed to give the rigid lenses a try. The diagnostic GPs dropped low on the patient’s eye and would likely drop lower due to the increase in plus power. As such, I made the front optic zone smaller to decrease the weight of the lens. The following lenses were ordered:
- 7.90/+18.00/9.8, standard edge, BXO material, green, Foz: 7.5 standard edge OD
- 8.00/+17.00/9.8, standard edge, BXO material, blue, Foz: 7.5 standard edge OS
GP Dispensing Visit
The patient presented after another two weeks. After placing lenses on the patient’s eyes and allowing them to settle, they were lid attached and centered with adequate movement. Vision was 20/20 OU with no over-refraction. The patient was still uncomfortable, however, and could not keep her eyes open. She was trained on lens insertion and removal and asked to build up wear time a few hours per day.
Follow-up Visit #1
The patient returned two weeks later with complaints that she was not able to adapt to her GP lenses and the most she could wear them was four hours per day. Even though her vision was clear, the patient still felt she couldn’t keep her eyes open.
We discussed alternate options, including piggyback lenses and scleral lenses. While scleral lenses often provide good comfort, I had concerns about the thickness of the high plus lens with her history of corneal neovascularization. When discussing piggyback lenses, the patient was resistant to the idea of wearing two sets of lenses. However, she also expressed interest in changing her eye color, so I brought up the option of piggybacking colored lenses under her GPs and she agreed.
I placed plano power Air Optix Colors (Alcon) lenses in green on the patient’s eyes underneath the GPs. The lenses did not interfere with her vision and she reported that they were significantly more comfortable, so I sent her home to try the combination.
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| Soft colored contact lenses, shown above, can serve to make other modalities more appealing through piggybacking options. |
Follow-up Visit #2
The patient presented another two weeks later with both sets of lenses on her eyes. She was able to wear them for 12 to 14 hours per day, and her mother reported that the patient was more motivated to extend her wear time due to the color changing effect of the soft lenses. Her vision was stable and clear and comfort was good, so the prescription was finalized.
Discussion
Transitioning a soft lens wearer to GP lenses can be difficult for many patients, with infants and young children often adapting more easily than adults. In my clinical experience, it is easier to prescribe GP lenses for young children than it is to wait for a problem with soft lens wear before switching lens modalities. But when a soft lens wearer does present with problems, clinicians can often be successful at tranisitioning them to GP lenses for better vision. It simply takes patience, flexibility and—sometimes—a little creativity.
In this case, using colored soft lenses in a piggyback system was a unique approach that motivated this teenager into full-time GP wear, ultimately providing her both the vision and comfort she needed. Now that colored silicone hydrogel lenses are available, this is a safe option and something to consider with tough patients.5
1. Cromelin CH, Drews-Botsch C, Russell B, Lambert SR. Association of contact lens adherence with visual outcome in the Infant Aphakia Treatment Study: A secondary analysis of a randomized clinical trial. JAMA Ophthalmol. 2018;136(3):279-85. |
