A 24-year-old patient with previous congenital cataracts presented with aphakia, superior corectopia, and low-amplitude nystagmus, and required very high-plus rigid lens correction. Because the pupils were displaced superiorly, the functional pupil had to remain covered by a large, stable optical zone throughout the blink cycle. Horizontal visible iris diameter (HVID) was 10.6 mm in both eyes, and pupil diameters were 2.03 mm OD and 1.86 mm OS.
Historical Problem
The patient presented wearing previously prescribed 8.7 mm diameter high-plus corneal GP lenses without minus carriers. Both lenses decentered inferiorly, and the patient had learned to squeeze the lids to improve visual acuity. Our goal was to achieve a more stable physiologic lens position that properly covered the pupils.
Clinical Challenge
We ordered initial corneal GP trials with a 9.5 mm diameter, 7.5 mm optical zone, and minus carrier. Centration improved, but glare and reflections persisted because the optical zone did not consistently cover the displaced pupil. Thus, an apparently acceptable static fit still produced transition-zone awareness during lens movement (Figures 6-9).
In the right eye, increasing the overall diameter to 10.6 mm and the optical zone to 8.8 mm produced substantially better centration and resolved the fitting problem. The left eye remained more challenging; although a larger corneal GP lens improved positioning, vertical movement during blinking intermittently exposed the optical zone transition and produced reflections (Figures 10 and 11).
Resolution
A 14.5 mm corneoscleral design (Table 1; Figures 12 and 13) was therefore selected for the left eye to provide greater optical stability. Diagnostic fitting showed excellent clearance and centration. The final design was planned with a 200 Dk material and a 9.0 mm anterior optical zone to maintain coverage of the displaced pupil while reducing unnecessary lens thickness.
|
Parameter |
Current CXL design |
|---|---|
|
Base curve |
41.00 D |
|
Intended power |
+20.75 D (verify clinically after receipt/test) |
|
Overall diameter |
14.5 mm |
|
Anterior optical zone |
9.0 mm |
|
SAG |
3.515 mm |
|
Center thickness |
0.82 mm |
|
Material Dk |
200 |
|
Clinical objective |
Stable optical zone/pupil alignment with optimized thickness and clearance |
Table 1: Final corneoscleral lens design planned for OS ordered, to be evaluated.
Conclusion
This case illustrates that in aphakia with superior corectopia, successful fitting depends not only on corneal alignment but also on stable optical zone coverage throughout blinking.
References
1. Levitt A. Specific Gravity and RGP lens performance. Contact Lens Spectrum. 1996;11(10). Published October 1, 1996. Accessed September 17, 2026.https://clspectrum.com/issues/1996/october/specific-gravity-and-rgp-lens-performance
1. Amos CF, Lambert SR, Ward MA. Rigid gas permeable contact lens correction of aphakia following congenital cataract removal during infancy. J PediatrOphthalmol Strabismus. 1992 Jul-Aug;29(4):243-245. doi: 10.3928/0191-3913-19920701-133
2. Abdalla WM, Sharef N, Alhalabi R. Unilateral isolated congenital ectopic pupil (corectopia) in a four-year-old child: case report and literature review. Cureus. 2023;15(9):e45090. doi: 10.7759/cureus.450904.
3. Tucker A. Contact lens fitting indications for the pediatric population. Modern Optometry. January/February 2025. Published January 29, 2025. Accessed September 17, 2026.modernod.com/topics/contact-lenses/contact-lens-fitting-indications-for-the-pediatric-population/38929