Changes in intraocular pressure and ocular pulse amplitude with accommodation
- Scott A Read,
- Michael J Collins,
- Heidi Becker,
- Jeremy Cutting,
- Danielle Ross,
- Annyck K Savill,
- Beth Trevor
- Contact Lens and Visual Optics Laboratory, School of Optometry, Queensland University of Technology, Brisbane, Australia
- Correspondence to Dr Scott A Read, Room D517, O Block, Victoria Park Road, Kelvin Grove 4059 Brisbane, Queensland, Australia;
- Accepted 20 September 2009
- Published Online First 12 October 2009
Aims To investigate the change that occurs in intraocular pressure (IOP) and ocular pulse amplitude (OPA) with accommodation in young adult myopes and emmetropes.
Methods Fifteen progressing myopic and 17 emmetropic young adult subjects had their IOP and OPA measured using the Pascal dynamic contour tonometer. Measurements were taken initially with accommodation relaxed, and then following 2 min of near fixation (accommodative demand 3 D). Baseline measurements of axial length and corneal thickness were also collected prior to the IOP measures.
Results IOP significantly decreased with accommodation in both the myopic and emmetropic subjects (mean change −1.8±1.1 mm Hg, p<0.0001). There was no significant difference (p>0.05) between myopes and emmetropes in terms of baseline IOP or the magnitude of change in IOP with accommodation. OPA also decreased significantly with accommodation (mean change for all subjects −0.5±0.5, p<0.0001). The myopic subjects (baseline OPA 2.0±0.7 mm Hg) exhibited a significantly lower baseline OPA (p=0.004) than the emmetropes (baseline OPA 3.2±1.3 mm Hg), and a significantly lower magnitude of change in OPA with accommodation.
Conclusion IOP decreases significantly with accommodation, and changes similarly in progressing myopic and emmetropic subjects. However, differences found between progressing myopes and emmetropes in the mean OPA levels and the decrease in OPA associated with accommodation suggested some changes in IOP dynamics associated with myopia.
Competing interests None declared.
Ethics approval This study was conducted with the approval of the Queensland University of Technology Human Research Ethics Committee. All participants were treated in accordance with the declaration of Helsinki.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.