Effect of Allergic Diseases on Keratoconus Severity.

PURPOSE: To investigate the association between keratoconus (KC) and allergic diseases. METHODS: In a prospective age- and sex-matched case--control study clinical data of 885 KC patients and 1526 controls were evaluated regarding the presence of various allergic diseases. Severity of KC and ophthalmic parameters of KC patients were compared between KC patients with and without allergic diseases. RESULTS: The prevalence of allergic diseases was significantly higher in KC patients. KC patients with vernal keratoconjunctivitis (VKC) or allergic conjunctivitis (AC) had significantly thinner and steeper corneas in comparison with non-allergic KC patients. Only VKC and AC were significantly associated with KC severity. CONCLUSIONS: Patients with VKC or AC were at increased risk of KC. They had more severe KC and should be closely followed up and intensively treated.

Association between Family History and Keratoconus Severity.

PURPOSE: The high prevalence of positive family history of keratoconus (KC) in KC patients is well-known. However, the results regarding the association between family history of KC and disease severity are controversial. The aim of this study was to evaluate the possible association between family history and severity of KC. METHOD: Clinical data of 1496 KC patients were evaluated. All participants were asked if they had had a family member with KC. Topographic and keratometric measurements of KC patients, including central corneal thickness (CCT), thinnest corneal thickness (TCT), mean, flat, and steep keratometry values (K) by the use of Pentacam, best-spectacle corrected visual acuity (BCVA), spherical equivalent (SE), and astigmatism were recorded and compared according to patients with and without a family history of KC, first- or second-degree family members, and the number of family members with KC. Severity of KC was classified according to the Amsler-Krumeich classification. RESULTS: Family history of KC was present in 292 (19.5%) patients. Of those 292 patients who had a family history of KC, 159 (54.5%) had one family member with KC and 133 (45.5%) had two or more family members with KC. There was not a significant difference between corneal pachymetry and K values of the patients with and without a family history of KC (p > 0.05). However, those with a positive family history of KC had more severe disease, according to the Amsler-Krumeich classification (p < 0.05). KC patients who had more family members with KC had significantly lower TCT and significantly higher steep K and astigmatism (p < 0.05), and had more severe disease, according to the Amsler-Krumeich classification (p < 0.05). CONCLUSION: We suggest that patients with more family members with KC should be subject to screening to identify early disease.