Clinical Study
Eye (2007) 21, 624–632. doi:10.1038/sj.eye.6702293; published online 21 April 2006
Dynamics of ocular surface topography
The authors transfer copyright of this paper to The Royal College of Ophthalmologists. The presented material has not been published elsewhere
M Zhu1, M J Collins1 and D R Iskander1
1Contact Lens and Visual Optics Laboratory, School of Optometry, Queensland University of Technology, Kelvin Grove, Australia
Correspondence: M Zhu, Department of Ophthalmology, University of Pittsburgh, Room 2953, 5th Avenue, Children's Hospital of Pittsburgh, Pittsburgh, PA 15213, USA. Tel: +1 412 692 6816; Fax: +1 412 692 7220. E-mail: zhum@upmc.edu
Received 9 June 2005; Accepted 15 January 2006; Published online 21 April 2006.
Abstract
Purpose
To investigate fluctuations in the ocular surface, we used high-speed videokeratoscopy (50 Hz) to measure the dynamics of the ocular surface topography.
Methods
Ocular surface height difference maps were computed to illustrate the changes in the tear film in the inter-blink interval. Topography data were used to derive the ocular surface wavefront aberrations up to the fourth radial order of the Zernike polynomial expansion. We examined the ocular surface dynamics and temporal changes in the ocular surface wavefront aberrations in the inter-blink interval.
Results
During the first 0.5 s following a blink, the ocular surface height at the upper edge of the topography map increased by about 2 
m. Temporal changes occurred for some ocular surface wavefront aberrations and appeared to be related to changes in the distribution of tear film.
Conclusion
In the clinical measurement of ocular surface topography using videokeratoscopy or optics of the eye using wavefront sensors, care should be taken to avoid the initial tear film build-up phase following a blink to achieve more consistent results.
Keywords:
ocular surface topography, ocular surface aberrations, ocular microfluctuations, high-speed videokeratoscopy
