Skip to main content

Research Repository

Advanced Search

Topographic indications of emerging keratoconus in teenage New Zealanders

Gamble, Greg D.; Boyce, Nicola K.; Owens, Helen; Bjornholdt, Melissa C; Keung, Lynnell


Greg D. Gamble

Nicola K. Boyce

Helen Owens
Senior Lecturer in Optometry

Melissa C Bjornholdt

Lynnell Keung


PURPOSE: To screen a population of teenagers for emerging topographic signs of keratoconus (KC), with particular reference to ethnicity. METHODS: Corneal topography, visual acuity, and an environmental risk factor analysis were included in a screening program designed to identify early indications of potential KC in teenagers. Two schools from central North Island, New Zealand, were invited to participate: one with predominantly Maori/Polynesian students and the other with students of mainly European descent. RESULTS: A total of 198 Maori/Polynesian, 16.8 ± 1.05 years of age, and 243 European students, 16.2 ± 1.3 years of age, participated in the study. Corneal topography suggestive strongly of KC was evident in 3 Maori/Polynesian [1.2%; 95% confidence interval (CI): 0.3-4.3] and no European students (0%; 95% CI, 0%-1.5%). Anomalous corneal topography reminiscent of emerging KC in at least 1 eye were found in 19% (95% CI, 15.6%-22.9%). A significant difference (P = 0.0014) in the percentage of suspected KC was found between European students (12.9%; 95% CI, 9.2%-17.9%) and Maori/Polynesian students (26.9%; 95% CI, 21.0%-33.7%). In multivariate analyses, the significant independent predictors of probable or suspected KC included being Maori/Polynesian [odds ratio (OR) = 2.1; 95% CI, 1.25-3.54; P = 0.0052], increasing age (OR = 1.4; 95% CI, 1.10-1.80; P = 0.0067), and a history of hayfever (OR = 2.0; 95% CI, 1.16-3.59; P = 0.013). Topographical indicators that were associated significantly with suspected KC included central keratometry (P < 0.0001), astigmatism (P = 0.014), and inferior-superior asymmetry (P < 0.0001). CONCLUSIONS: Although only a longitudinal study will determine the proportion of true KC candidates, these data provide evidence of ethnicity-related differences in corneal topography in teenage New Zealanders. © 2007 Lippincott Williams & Wilkins, Inc.


Boyce, N. K., Gamble, G. D., Owens, H., Bjornholdt, M. C., & Keung, L. (2007). Topographic indications of emerging keratoconus in teenage New Zealanders. Cornea, 26(3), 312-318.

Journal Article Type Article
Acceptance Date Nov 18, 2006
Publication Date Apr 1, 2007
Deposit Date Jul 31, 2018
Journal Cornea
Print ISSN 0277-3740
Publisher Lippincott, Williams & Wilkins
Peer Reviewed Peer Reviewed
Volume 26
Issue 3
Pages 312-318
Public URL
Publisher URL