Changes in iridocorneal angle configuration and intraocular pressure during smartphone use under room light

Purpose: To investigate changes in intraocular pressure (IOP) and iridocorneal angle (ICA) configuration during smartphone use under room light. Methods: We included healthy adults aged 19-35 years with no ophthalmological abnormalities. All read text on a smartphone for 6 minutes under room light. IOP was measured via rebound tonometry at baseline and at 2, 4, and 6 minutes. ICA images were obtained via anterior segment optical coherence tomography after each IOP measurement. After 6 minutes, participants stopped reading text and rested for 2 minutes. IOP was then measured again. Results: The IOP significantly increased at 2, 4, and 6 minutes of reading compared to baseline (p < 0.001) but recovered to baseline after 2 minutes of rest (p = 1.000). The anterior chamber depth decreased significantly, and the anterior chamber angle width increased after 6 minutes of smartphone reading (both p < 0.05). Conclusions: IOP increased when reading smartphone text under room light but the ICA did not change. Prolonged smartphone reading is inappropriate for a patient at risk of glaucoma or glaucoma progression. Such patients should be cautioned.