[Form deprivation myopia caused by keratitis scrophulosa]

Zrenner and Schaeffel reported that translucent occluders may induce axial eye elongation in animals. This axial growth is also called form deprivation myopia (FDM). Searching for a clinical correlate we examined in a retrospective study 115 patients with keratitis scrophulosa peracta, mainly corneal transplant patients. These patients had an average refraction of -4.27 dpt. In epidemiologic studies Stenström found +0.5 dpt as the mean refraction in the general population. When the onset of the corneal disease was before the age of 5 years, the myopia was found to be higher than in patients with later age of onset. In 43 patients we determined axial length by ultrasound biometry and found an average axial length of 26.89 mm, whereas the general average is 24.00 mm. In conclusion, these results confirm that not only in animal experiments but also in clinical cases FDM is responsible for the axial growth of eyes.