title: The natural history of corneal topographic progression of keratoconus after age 30 years in non-contact lens wearers.
abstract: To determine if significant progression of disease occurs in older, non-contact lens wearing, subjects with keratoconus and to identify potential predictive factors.
  
  
  
  Clinical and computerised corneal topography records of subjects with keratoconus attending a specialist optometry practice were retrospectively analysed to identify those aged ≥30 years, with ≥2 consultations ≥12 months apart, no contact lens wear and no corneal scarring, surgery or corneal hydrops. Topographic parameters assessed included: maximum keratometry (Kmax), steep keratometry (Ksteep), flat keratometry (Kflat), inferior-superior (I-S) ratio and the surface asymmetry and regularity (surface asymmetry index and surface regularity index) indices.
  
  
  
  Of the 449 subjects with keratoconus assessed, 43 eyes of 27 patients (6.01%) met inclusion criteria, with median age 38.45 (12.86) years at baseline and median follow-up 4.36 (8.68) years. There was a significant increase in Kmax (0.30 (1.21) D), Ksteep (0.27 (0.90) D), Kflat (0.34 (1.12) D) and I-S (0.26 (0.82) D) between baseline and final review, p<0.05. Notably, 18.6%-25.6% of eyes demonstrated ≥1.00 D increase in one or more of four principal topographic parameters (Kmax, Ksteep, Kflat, I-S ratio), while 18.5%-37.0% of subjects had ≥1.00 D increase in the aforementioned parameters in at least one eye over the study period. However, <10% of eyes exhibited ≥1.00 D increase/year in all topographic parameters. The only significant predictor of progression was follow-up time.
  
  
  
  This study confirms that keratoconus may continue to progress beyond age 30. Older subjects with keratoconus should be monitored for progression, particularly with respect to possible corneal collagen cross-linking or astigmatic correction in cataract surgery.
authors.affiliation: Faculty of Medical and Health Sciences, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
authors.forename: Akilesh
authors.identifier: 0000-0003-0643-9420
authors.initials: A
authors.lastname: Gokul
authors.affiliation: Faculty of Medical and Health Sciences, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
authors.forename: Dipika V
authors.initials: DV
authors.lastname: Patel
authors.affiliation: Faculty of Medical and Health Sciences, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
authors.forename: Grant A
authors.initials: GA
authors.lastname: Watters
authors.affiliation: Faculty of Medical and Health Sciences, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
authors.forename: Charles N J
authors.initials: CNJ
authors.lastname: McGhee
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods*; D018450:Disease Progression; D005139:Eyeglasses; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014792:Visual Acuity
keywords: Cornea; Imaging