CONTACT LENS CASE REPORTS
FITTING MICROPHTHALMIA AND NYSTAGMUS
PATRICK J. CAROLINE & MARK P. ANDRÉ
Microphthalmia (small eye) and anophthalmia (absent eye) are congenital conditions that can occur secondary to genetic mutations and environmental insults during fetal development. The malformations are often associated with other ocular findings, such as anterior and posterior segment colobomas and nystagmus, as well as with syndromes involving cardiac, neuropsychiatric, and craniofacial abnormalities. This case highlights some of the difficulties in fitting contact lenses for these patients.
A 28-year-old male presented to our clinic with an ocular history that was significant for nystagmus and left eye microphthalmia and aniridia, right eye anophthalmia (Figure 1). The patient presented with an uncorrected visual acuity of 20/100 in his microphthalmic left eye; his right anophthalmic eye had an ocular prosthesis.
Figure 1. The patient’s right eye with an ocular prosthesis and left eye with microphthalmia and aniridia.
Preliminary testing revealed nystagmus with a null point in far right gaze, with grossly full extraocular motility. Due to the extreme position of his null point, the patient’s habitual spectacle frames obstructed his gaze and provided no improvement in visual acuity. Anterior segment optical coherence tomography (OCT) revealed a shallow anterior chamber (Figure 2). Corneal topography revealed high irregular astigmatism, with simulated K values of 37.25/55.50 @ 088 (9.06/6.08mm @ 088). Horizontal visible iris diameter (HVID) OS was 7.9mm. Posterior segment evaluation revealed a staphyloma and retinal coloboma OS.
Figure 2. Anterior segment OCT illustrating shallow anterior chamber and aniridia of the patient’s left eye (top) and a normal eye for comparison (bottom).
Finding the Right Fit
The first diagnostic lens was a 14.5mm scleral lens; however, despite an appropriate fitting relationship, the lens failed due to patient difficulties with bubble formation upon lens application complicated by his nystagmus.
After a number of trials with corneal lenses, the patient was successful with a 9.0mm diameter lens with a base curve of 8.00mm and a power of –11.00D (Figure 3). The patient reported noticeable improvement in his vision, now 20/50, and he was successful with application and removal procedures. Plano spectacles were prescribed to wear over the lens for ocular protection.
Figure 3. Well-centered 9.0mm corneal contact lens.
This case demonstrates that contact lenses can provide functional improvement in vision for some patients who have microphthalmia. It also highlights some of the unique challenges involved in fitting contact lenses on these patients. Proper lens centration is often difficult, and non-standard fitting relationships are often required. Application and removal training can be complicated by poor vision and nystagmus. In patients who have only one functioning eye, monocular precautions must be considered. CLS
The authors would like to thank Dr. Emily Korszen for her assistance with this case report.
Patrick Caroline is an associate professor of optometry at Pacific University.
Mark André is an associate professor of optometry at Pacific University. He is also a consultant to CooperVision