Diurnal variations of axial length and IOP over two consecutive days

Ranjay Chakraborty, S Read, Michael Collins

Research output: Contribution to conferenceAbstractpeer-review


Purpose: The aim was to investigate the pattern of diurnal variations in axial length (AL), anterior eye biometrics (AEB) and intraocular pressure (IOP) over two consecutive days. Methods: Measurements of ocular biometrics and IOP were collected for 30 young adult subjects (mean age: 25.16 ± 3.32 years) at 10 different times over two consecutive days. Five measurements were collected each day at approximately three-hourly intervals, with the first measurement taken at approximately 9 am and the final measurement at approximately 9 pm. Axial length and anterior eye biometric parameters were measured with the Lenstar LS 900 optical biometer, while the Ocular Response Analyser was used to measure IOP. Results: Axial length was found to undergo significant diurnal changes (p < 0.0001) that were consistently observed across the two measurement days. The maximum axial length was typically observed at the second measurement session (mean time 12:26 pm) and the minimum axial length at the final session of each day (mean time 09:06 pm). The mean magnitude of change in axial length was 32 ± 18 mm. Significant diurnal variations were also found in IOP (p < 0.0001). The mean magnitude change in IOP was 3.54 ± 0.84 mmHg. A weak but statistically significant association was found between the changes in axial length and IOP (r2 = 0.169, p < 0.0001). AEB, central corneal thickness (p < 0.0001) and anterior chamber depth (p < 0.0001) were also found to undergo significant diurnal changes. Conclusion: Significant diurnal variations were found in axial length, IOP and anterior eye biometrics that were consistently observed over two consecutive days of testing.
Original languageEnglish
Publication statusPublished - Sep 2010
Externally publishedYes
Event13th Scientific Meeting in Optometry and 7th Optometric Educators Meeting - Sydney, Australia
Duration: 1 Sep 2010 → …


Conference13th Scientific Meeting in Optometry and 7th Optometric Educators Meeting
Period1/09/10 → …


Dive into the research topics of 'Diurnal variations of axial length and IOP over two consecutive days'. Together they form a unique fingerprint.

Cite this