To describe the clinical characteristics and outcomes of acute acquired comitant esotropia (AACE) related to excessive smartphone use in adolescents. The medical records of 12 patients with AACE and a history of excessive smartphone use were retrospectively reviewed, and the duration of smartphone use, angle of deviation, refractive error, stereopsis, and treatment options were analyzed. All patients showed convergent and comitant esotropia ranging from 15 to 45 prism diopters (PD; average: 27.75 ± 11.47 PD) at far fixation. The angle of deviation was nearly equivalent for far and near fixation. Every patient used a smartphone for more than 4 h a day over a period of several months (minimum 4 months). Myopic refractive errors were detected in eight patients (average:−3.84 ± 1.68 diopters (D]), and the remaining four patients showed mild hyperopic refractive error (average: +0.84 ± 0.53 D). Reductions in esodeviation were noted in all patients after refraining from smartphone use, and bilateral medial rectus recession was performed in three patients with considerable remnant esodeviation. Postoperative exams showed orthophoria with good stereoacuity in these patients. Excessive smartphone use might influence AACE development in adolescents. Refraining from smartphone use can decrease the degree of esodeviation in these patients, and remnant deviation can be successfully managed with surgical correction.

Purpose.: To determine whether acute intraocular pressure (IOP) elevation alters dynamin-related protein 1 (Drp1) as well as whether a selective inhibitor of Drp1, mdivi-1, can block apoptotic cell death and subsequently increase retinal ganglion cell (RGC) survival in ischemic mouse retina. Methods.: C57BL/6 mice received injections of mdivi-1 (50 mg/kg) or vehicle, and then transient retinal ischemia was induced by acute IOP elevation. RGC survival was measured after FluoroGold labeling. Drp1 and glial fibrillary acidic protein (GFAP) protein expression and distribution were assessed at 12 hours after ischemia–reperfusion by Western blot and immunohistochemistry. Apoptotic cell death was assessed by TUNEL staining. Results.: Drp1 and GFAP protein expression was significantly increased in the early neurodegenerative events (within 12 hours) of ischemic mouse retina. Mdivi-1 treatment blocked apoptotic cell death in ischemic retina, and significantly increased RGC survival at 2 weeks after ischemia. In the normal mouse retina, Drp1 is expressed in the ganglion cell layer (GCL) as well as the inner plexiform layer, the inner nuclear layer (INL), and the outer plexiform layer (OPL). In the GCL, Drp1 immunoreactivity was strong in RGCs. While Drp1 protein expression was increased in the GCL of vehicle-treated ischemic retina at 12 hours. Mdivi-1 treatment did not change this increase of Drp1 protein expression but significantly decreased GFAP protein expression. Conclusions.: These findings suggest that altered Drp1 activity after acute IOP elevation may be an important component of a biochemical cascade leading to RGC death in ischemic retina.

Background: To investigate the differences in refraction, accommodative factors, visual parameters, and subjective symptoms after using two types of virtual reality (VR) content with different depths of perception. Methods: Twenty-three volunteers, who played VR games in two modes (immersive and non-immersive) for 30 min, were enrolled. Visual parameters were examined before and after using VR. Accommodative factors were measured using static and dynamic methods. Subjective symptoms were assessed using a questionnaire. Differences according to VR content were compared, and correlations between each visual parameter were analyzed. Results: There were no changes in refraction or accommodative factors after use of the VR. However, there was a significant increase in the near point of accommodation (NPA), the near point of convergence (NPC), and subjective symptom scores after using the immersive mode. Correlation analysis revealed a positive correlation between baseline values of near exophoria and mean accommodative lag of the dominant eye, and also revealed a negative correlation between NPA and mean accommodative lag in the non-dominant eye. Conclusions: The use of VR for 30 min increased NPA and NPC, especially after the immersive mode was used. In addition, higher exophoria and smaller NPA is associated with increased accommodative lag after using VR.