Clinical status, ocular surface changes and tear ferning in patients with cystic fibrosis.

Twenty-three cystic fibrosis patients and 20 controls were examined for ocular surface changes and tear fluid ferning characteristics. The patients were also evaluated systemically and given numerical scores according to Schwachman's scoring system. Frequency of blepharitis, fluorescein staining, and the Schirmer's test values did not differ between patients and controls. Patients with cystic fibrosis had a higher frequency of altered ferning pattern that corresponded to the disease severity as measured by the Schwachman score (r = -0.48, p < 0.05). Although altered ferning pattern was frequent, the rate of type I ferning was also high (30%) in patients with cystic fibrosis. We conclude that the ferning test should not be used as an aid in diagnosis of cystic fibrosis but it may be used as an indicator of clinical status during follow-up.