Accommodation-induced intraocular pressure changes in progressing myopes and emmetropes

To investigate the changes of intraocular pressure (IOP) and anterior eye segment biometric parameters under different accommodative statuses in progressing myopes and emmetropes.

Forty-six progressing myopes and 40 emmetropes participated in this study. All the subjects had their IOP and anterior eye segment biometric parameters (including corneal thickness, anterior chamber depth, anterior chamber angle width, and lens thickness) measured using iCare rebound tonometer and VisanteTM anterior segment-optical coherence tomography while accommodative stimuli of 0, 3, and 6D were presented.

There was no significant difference in IOP between progressing myopes and emmetropes when no accommodation was induced (16.22±4.11 vs 17.01±3.72, respectively, t=-0.93, P>0.05). However, IOP significantly increased with accommodation in progressing myopes (mean change +1.02±2.07 mm Hg from 0D to 6D, F=5.35, P<0.01), but remained unchanged (mean change -0.76±3.22 mm Hg from 0D to 6D, F=1.46, P>0.05) in emmetropes. Meanwhile, we found that their anterior chamber depth decreased (P<0.01), anterior chamber angle narrowed (P<0.01), and lens thickened (P<0.01) significantly with accommodation, both in progressing myopes and emmetropes.

Although no difference was detected between the IOPs of progressing myopes and emmetropes without accommodation, accommodation could induce transient IOP elevation in progressing myopes. Simultaneously, we found that their anterior chamber depth decreased, anterior chamber angle narrowed, and lens thickened with accommodation. Although emmetropes showed the similar anterior eye segment structure changes, their IOPs did not increase with accommodation. Our study indicated that IOP elevation with accommodation in progressing myopes might be related to myopia progression.