Static and repeated accommodation both significantly reduce IOP

Both static and repeated accommodation significantly reduce intraocular pressure (IOP), reveals a paper in the Journal of Glaucoma.

Dr Frank Jenssen et al., Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway, included 33 healthy participants aged 20 to 29 years in a randomized, single-blind study.

After viewing a target in the distance for 10 minutes baseline IOP was measured. Participants focused on a near target for three minutes to achieve static accommodation. Volunteers were also asked to alternate their focus on near and distant targets for three minutes to achieve repeated accommodation.

An infrared photoreceptor was used to continuously monitor accommodative responses and Goldmann tonometry was conducted straight after the accommodative process.

After static accommodation IOP was 13.4±2.4 mmHg and for repeated accommodation it was 12.7±2.3 mmHg. This demonstrated a mean change in IOP of −1.76±1.17 mmHg and −2.06±1.48 mmHg, for static and repeated accommodation respectively. Although the drop was greater in repeated accommodation than static, the difference was not statistically significant.

The investigation suggests that aqueous humour outflow isn't strongly influenced by recurrent ciliary muscle contractions.