The Dundee University Scottish Keratoconus study: demographics, corneal signs, associated diseases, and eye rubbing.
OBJECTIVE
To investigate and correlate the corneal, refractive, topographic and familial characteristics of a large cohort with keratoconus.


METHODS
Prospective observational study of 200 consecutive patients presenting with keratoconus during the 4 year-period 1997-2000. Subjects were examined at enrolment and at a final review. Data were collected on demographic characteristics, referral route, symptoms, refractive correction, eye rubbing, family history, medical history, slit-lamp biomicroscopic corneal signs, and computerized corneal topography.


RESULTS
Mean age at enrolment was 30.9+/-10.4 (range, 12.2-72) years (N=200, 62.5% male, 93% white Caucasian) with a 5% family history of keratoconus. Atopic diseases included asthma (23%), eczema (14%), and hay fever (30%). Only 9% wore contact lenses before referral. Mean follow-up was 1004 days +/-282 (range, 390-1335) and 9.7+/-8.9 (range, 1.1-60) years from diagnosis. The mean simulated K1 corneal power at enrolment was 51.74+/-5.36 (range, 42.59-67.32) D and 88.5% exhibited bilateral keratoconus. Fifty-three (15%) topographically confirmed cones exhibited no clinical corneal signs at presentation. At enrollment, 56% had a pachymetry <0.480 mm increasing to 77% at final review. Forty-eight percent of subjects reported significant eye rubbing and there was a highly statistically significant difference (two sample t-test P=0.018) between keratoconus and control groups. TMS-2 axial corneal power was strongly associated with corneal scarring and age at diagnosis. The size of the scarring effect was 2.2 D (95% confidence interval (CI) 1.34, 3.06).


CONCLUSIONS
This study provides an overview of a large population with keratoconus highlighting presenting features and clinical and topographic progression over a 4 year-period.
Weed
K H
KH
Department of Ophthalmology, Ninewells Hospital and Medical School, Dundee, Scotland, UK. k.h.weed@dundee.ac.uk
MacEwen
C J
CJ
Giles
T
T
Low
J
J
McGhee
C N J
CN
D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000150:complications; D019781:Corneal Topography; D004485:Eczema / Q000150:complications; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D010812:Physical Stimulation / Q000009:adverse effects*; D011446:Prospective Studies; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology