Abstract
Limbal stem cell deficiency (LSCD) is characterized by a decreased ability to replenish the population of corneal epithelial cells, resulting in corneal neovascularization, surface defects, scarring and replacement of the corneal epithelium with conjunctival epithelial cells. Familial LSCD with minimal or no other ocular pathology is an extremely rare condition.
In some but not all families coding or splicing pathogenic mutations in the paired box gene 6 (PAX6, MIM *607108) have been detected .The proband first developed ocular symptoms at the age of 3 years, when she had been examined for redness and tearing of the right eye (RE). Peripheral superficial corneal vascularization, rough uneven corneal surface and scarring in the RE were documented in historical notes.
At the age of 12 years her best corrected visual acuity (BCVA) in the RE was recorded to be hand motion. Apart from decreased BCVA, her main subjective symptoms have been recurrent periods of light sensitivity and foreign body sensation associated with profound redness occurring often in the RE and occasionally in the left eye (LE).
Since 25 years of age, these symptoms have been managed by daily contact lens wear in the RE. In addition to the recommendation to administer regularly artificial tears, she has been prescribed intermittently mild steroid drops, topical cyclosporine A and anti-VEGF therapy (bevacizumab); however, these compounds provided little or no relief.
Examination at 30 years of age revealed a marked asymmetry in her clinical features. In the RE, extensive vascularization of the entire cornea and stromal scarring with yellowish deposits was observed (Fig. 1a).
BCVA was hand motion. In the LE, a circular peripheral vascularization was observed that was most pronounced in the superior cornea where it extended about 3 mm from the limbus; the corneal stroma was otherwise clear.
Uncorrected visual acuity in the LE was 1.0. Re-examination of the proband at the age of 36 years did not reveal any progression (Fig. 1d, e).
Mild corectopia and loss of the limbal palisades of Vogt was observed bilaterally (Fig. 1a, b, d, e). Spectral domain optical coherence tomography (SD-OCT; Spectralis; Heidelberg Engineering GmbH, Heidelberg, Germany) scans of the right cornea showed irregular corneal thickness and thinning up to 251 μm (Fig. 1c).
SD-OCT imaging of the macula did not reveal any abnormalities in both eyes (Supplementary Fig. 1).