The Dundee University Scottish Keratoconus Study II: a prospective study of optical and surgical correction

AIM: To investigate and correlate optical correction, and progression to penetrating keratoplasty (PKP), with the corneal, refractive, topographic and familial characteristics of subjects with keratoconus, within the Tayside region of Scotland. METHOD: Prospective, observational, longitudinal study design. Two hundred subjects with keratoconus were enrolled into the Dundee University Scottish Keratoconus Study (DUSKS) and were assessed during a 4-year period using standardised clinical assessment, computerised corneal topography and questionnaires. RESULTS: Keratoconic subjects in this study wore rigid contact lenses (90.6%) for longer than 12 hours per day (81%), 7 days a week (91%) and achieved a very good level of Snellen visual acuity (97%, > or =6/9). Corneal staining was observed in the majority of corneas (71%), although only a small percentage of subjects reported major problems of: discomfort (18%), hyperaemia (16%), or the lens falling out (4%). Poor visual acuity was the main reason (79%) for undergoing PKP usually in the latter part of the third decade of life, approximately a decade after diagnosis. During the study period 4% of eyes progressed to PKP. Only a small percentage of eyes (9.5%) required no visual correction postoperatively. CONCLUSION: The main mode of visual rehabilitation for keratoconus was rigid contact lenses, which were mostly worn successfully with good visual acuity. During the study period a small minority of keratoconics progressed to corneal graft surgery. It is advisable to emphasise that postoperatively refractive correction will be required in the majority of these cases.