Aims: To define the variability and repeatability of retinal thickness measurements using the retinal thickness analyser (RTA) and to elucidate any interaction between eccentricity (that is, position relative to the fovea) and variability and repeatability.
Methods: The sample comprised 20 normal subjects of mean age 33 years. Each subject attended for two visits. Repeated RTA scans were acquired centred on the fovea and for any one of the four possible non-foveal scan areas. The mean retinal thickness (+SD) was calculated for a series of concentric circular bands centred on fixation. A repeated measures analysis of variance (ANOVA) was used to determine any significant interaction between the variability of RTA thickness values and eccentricity.
Results: The group mean coefficient of variation and coefficient of repeatability were highest at the fovea. The repeated measures ANOVA revealed that the within test variability of RTA measurements varied significantly with eccentricity (p<0.0001). Similarly, the between test repeatability varied significantly with eccentricity (p = 0.045).
Conclusion: The significantly elevated within test variability and between test repeatability in the foveal area need to be considered when using the RTA to evaluate patients with macular disease.
- measurement variability
- retinal thickness analyser
Statistics from Altmetric.com
Grant support: This work was funded by the Canadian Institutes of Health Research (Operating Grant and New Investigator Award to CH) and by a Premier’s Research Excellence Award (recipient CH).
Proprietary interest: The authors have no proprietary interest in the retinal thickness analyser.
This work was presented as a poster at the 2002 annual meetings of the Association for Research in Vision and Ophthalmology and of the American Diabetes Association
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.