Megalocornea is a condition in which the corneal diameter is larger than normal from birth, usually with normal corneal clarity and thickness. It reflects an enlarged anterior segment rather than raised intraocular pressure.
Features
The horizontal corneal diameter exceeds typical age-related norms, often without corneal clouding. Unlike congenital glaucoma, the cornea is usually clear and intraocular pressure may be normal, though associated anomalies can occur.
- Often inherited in an X-linked pattern but other forms exist
- High myopia or astigmatism may be present because of altered eye shape
- Zonular weakness and lens subluxation are reported in some cases
- Other anterior segment or systemic abnormalities can accompany the condition
Management
Care focuses on refractive correction and surveillance for complications such as lens instability or glaucoma. Because the eye is larger, surgical planning, for example for cataract extraction, must consider altered anatomy.
- Regular monitoring of intraocular pressure and optic nerves is recommended
- Children need early correction of refractive errors to reduce amblyopia risk
- Genetic counselling may be offered to affected families
- Detailed examination helps distinguish megalocornea from congenital glaucoma and other causes of large corneas
