Primary megalocornea: clinical features for differentiation from infantile glaucoma.

PURPOSE: To describe the ocular findings in megalocornea to assist in its differentiation from infantile glaucoma in the evaluation of children with abnormally enlarged corneas.

METHODS

The clinical findings of 4 boys found to have megalocornea following referral for evaluation of large corneas and suspected glaucoma were reviewed.

RESULTS

Three of the 4 patients had photophobia. Clear and enlarged corneas were observed associated with deep anterior chambers, posterior bowing of the irides, and normal intraocular pressures (IOPs) in all eyes. Transillumination of the irides was found in 6 of 8 eyes and pigment dispersion was seen in 4 of 8 eyes. Pigment dispersion appeared to be acquired over time, and the youngest patient in this series who had pigment dispersion detected on slit-lamp examination was 15 years; the youngest patient with the condition detected on gonioscopy was 8 years. No breaks in Descemet's membrane were present. Family history obtained from 3 of the 4 patients revealed evidence of sex-linked recessive inheritance. These findings are distinct from the clinical features of infantile glaucoma characterized by elevated IOP, breaks in Descemet's membrane, corneal edema, a generally flat iris profile, less pronounced enlargement of the anterior segment, the absence of iris transillumination and pigment dispersion, and autosomal recessive inheritance. Three patients had corneal size asymmetry, a finding that has not been previously reported.

CONCLUSION

Hereditary megalocornea has defining clinical findings that help to identify and differentiate it from other causes of enlarged corneas. Asymmetry in corneal size does not preclude its diagnosis.