Several gene mutations result in eyeballs (globes) that are either larger or smaller than normal. In nanophthalmos, the globe is smaller than average and for some, but not all patients there can be problems in the retina as well. All patients with such small eyeballs have a significant risk of acute glaucoma.
Abnormally small globes cause farsightedness and in nanophthalmos this may be severe. Because of crowding of structures in the eye, the normal escape route of the fluid from the eye is blocked leading to a rise in pressure. This may occur acutely, leading to what is called an ‘angle closure attack’ associated with severe pain and blurry vision. In the condition described here, there is also some degeneration of the retina causing nightblindness early in life with later severe loss of day and night vision. No abnormalities have been described in other parts of the body.
This is generally considered to be an autosomal recessive condition because many cases are born to related parents and the pattern is a horizontal one. However, the first family reported, in 1958, demonstrated a vertical pattern suggesting autosomal dominant inheritance. No gene mutation has been identified.
This disorder must be diagnosed by an ophthalmologist by doing a complete eye examination. It may be determined that there is a serious risk of an angle closure attack and, if so, preventative measures can be taken before it occurs. Your eye doctor may be able to create a small hole in the iris that reduces this risk. Of course, this does not prevent the continued deterioration of the retina and no treatment is available for that process.