[Clinical features of 233 cases of keratoconus]

To analyze clinical features of keratoconus.

The case history of keratoconus patients who underwent penetrating keratoplasty, epikeratophakia or deep lamellar keratoplasty in our hospital during January 1993 to March 2002 was reviewed, and inquiry form was sent to those who without complete data. Patients were followed during January 2000 to March 2002. Two hundred and thirty three cases of keratoconus were enrolled in this study with 216 males and 17 females. Patient's family history, systemic complications, refractive status, progress of disease, eye axial length and anterior chamber depth were recorded.

The clinical natural history of these patients followed the model of "myopia-astigmatism-poor spectacle correction-acute corneal hydrops or stromal scar". The presenting age of myopia ranged from 6 to 29 years, with a mean age of 13.8 years, 10.1% (22/219) of the patients were younger than 10 years, 67.1% (147/219) were between 11 and 15 years. The interval time between emerging myopia and poor spectacle correction (best corrected visual acuity less than 20/200) was ranged from 1 to 20 years, of which 85.2% (161/189) were shorter than 6 years. Twenty percent (47/233) of the patients had acute corneal hydrops in one eye at the age of 12 to 31 years, and 4.3% of them (2/47) resulted in corneal perforation. Thirty-four patients had corneal stromal scars 1 to 13 years after keratoconus developed, and 94.1% of them (32/34) were within 8 years. Topography examination demonstrated a tendency of the cone base position progress: first, paracentral-enlargement following dominant astigmatism axis, then, enlargement along smaller astigmatism axis, and finally, the cone base moving centrally. The eye axial length averaged at (25.9 +/- 1.4) mm, the depth of anterior chamber (AC) were (4.3 +/- 0.3) mm, 89.7% (279/311) eyes had an axial length longer than 24 mm. All cases had an asymmetry clinical progress course. Two cases had Down syndrome, 2 with intelligence defect. No family history was noted in this study.

Keratoconus in Han nationality of Shandong Province has a relatively earlier age onset. These eyes tend to have a deeper AC with higher incidence of longer axial length.