Abstract
Purpose: :
An asymmetric intraocular pressure (IOP) between the two eyes in the supine position but not detectable in the sitting position was referred to as a ‘latent asymmetric IOP’. To investigate its association with visual field (VF) deterioration in patients with open-angle glaucoma (OAG).
Methods: :
Fifty-three OAG patients with bilaterally symmetrical medication(s) were enrolled and housed in a sleep laboratory for 24-hours. IOP in sitting and supine positions were measured every 2 hours. At each time point, the IOP asymmetry between two eyes was calculated for each position. For the sitting position, any subject having an asymmetric IOP of at least 3 mmHg at any time during the 24 hour study period was defined as having an asymmetric sitting IOP. For the supine position, a cut off value for asymmetric IOP was set at 5 mmHg. A group of patients showed the symmetric IOP in the sitting position but asymmetric IOP in the supine position (latent asymmetric IOP) was identified. To find the impact of latent asymmetric IOP, we compared IOP fluctuations and VF indices of these patients with others.
Results: :
Of the study population, about 30% of patients had a latent asymmetric IOP. The hypertensive eyes in this group had a wider IOP fluctuation in both positions and more aggressive VF defects when compared to the fellow eye. And those eyes were found to have a significantly wider diurnal IOP fluctuation in both positions and worse VF than eyes in the symmetric IOP group.
Conclusions: :
Patients with ‘latent asymmetric IOP’ are at an increased danger of VF deterioration. Latent asymmetric IOP may be a predictor of glaucomatous VF defects. Further investigation in a larger and more diverse group of patients is needed to assess its value in glaucoma therapy.
Clinical Trial: :
www.clinicaltrials.gov NCT00481208
Keywords: intraocular pressure • visual fields