Original articleLongitudinal study of the normal eyes in unilateral keratoconus patients☆
Section snippets
Subjects
We prospectively recruited 778 patients with clinically diagnosed KC and 252 normal patients as controls as a part of a longitudinal videokeratography and genetic study at the Cedars-Sinai Medical Center, Los Angeles, California. Institutional Review Board/Ethics Committee approval was obtained.
The diagnosis of KC was made on the basis of clinical examination. Any patient who had 1 or more of the following clinical signs with no other pathology was classified as having KC: obvious corneal
Comparison between normal fellow eyes of KC patients and normal controls
The mean age at baseline in the unilateral KC patient group was lower than that in normal controls (34.28±12.24 vs. 38.81±12.18; P<0.001). There were more males in the unilateral KC patient group (62.9%) than in the controls (40.5%; P<0.0001). No significant difference in race was found between the 2 groups.
The clinically normal fellow eyes had higher I-S and logKISA values compared with normal controls at baseline (Table 1).
Estimated median time for the fellow eyes developing KC
Among 85 patients with at least 2 visits, the years of follow-up
Discussion
In this longitudinal study, we have provided new information regarding: (1) the incidence and duration of the progression of clinically normal fellow eyes to development of KC; (2) the predictive factors for developing KC in the normal eye; and (3) the distribution of qualitative and quantitative factors in normal eyes of KC patients.
As previously discussed, KC is most commonly bilateral, and the prevalence and incidence of unilateral KC varies, depending on the methods used for diagnosis. By
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Manuscript no. 230075.
Supported by the National Eye Institute (grant no.: NEI 09052, GCRC), the National Institutes of Health (grant no.: NIH 50091-06), the Eye Birth Defects Research Foundation Inc., and Center for Keratoconus.
The authors have no financial interest in the Topographic Modeling System (Computed Anatomy, Inc., New York, NY).