Multiple Short Daily Periods of Normal Binocular Vision Preserve Stereopsis in Strabismus

Assessment of autostereoscopic perception using artificial intelligence-enhanced face tracking technology

PURPOSE

Stereopsis, the ability of humans to perceive depth through distinct visual stimuli in each eye, is foundational to autostereoscopic technology in computing. However, ensuring stable head position during assessments has been challenging. This study evaluated the utility of artificial intelligence (AI)-enhanced face tracking technology in overcoming this challenge by ensuring that each eye consistently receives its intended image.

METHODS

The Lume Pad 2, an autostereoscopic tablet with AI-enhanced face tracking, was utilized to simulate quantitative parts of the Stereo Fly test and TNO Stereotests for contour and random dot stereopsis. The study recruited 30 children (14 males and 16 females, mean age of 9.2 ± 0.3 years, age range of 6-12 years) and 30 adults (10 males and 20 females, mean age of 29.4 ± 1.0 years, age range of 21-42 years) to assess the tablet's inter-session reliability. Agreement between conventional and the autostereoscopic tablet-simulated stereotests was tested in a larger group of 181 children (91 males and 90 females, mean age of 9.1 ± 0.4 years, age range of 6-12 years) and 160 adults (69 males and 91 females, mean age of 38.6 ± 2.1 years, age range of 21-65 years). Inter-session reliability and agreement were analyzed using weighted Kappa coefficient and non-parametric Bland-Altman analysis.

RESULTS

The autostereoscopic tablet demonstrated high inter-session reliability (κ all > 0.80), except for the simulated TNO Stereotest in adults, which demonstrated moderate inter-session reliability (κ = 0.571). Non-parametric Bland-Altman analysis revealed zero median differences, confirming consistent inter-session reliability. Similar patterns were observed in comparing AI-based and conventional methods, with both the weighted Kappa coefficient (κ all > 0.80) and non-parametric Bland-Altman analysis indicating significant agreement. The agreement between methodologies was confirmed by permissible differences, which were smaller than the minimum step range.

CONCLUSION

The integration of AI-based autostereoscopic technology with sub-pixel precision demonstrates significant potential for clinical stereopsis measurements.

Analysis of the Changes and Possible Reasons in Aberrations before and after Surgery in Patients with Concomitant Exotropia

Objective. The objective is to observe the changes in aberrations before and after surgery in patients with common horizontal strabismus and to analyze the possible reasons for the changes. Methods. Forty eyes of 40 cases with concomitant exotropia who underwent strabismus correction at the Ophthalmology Department of Nantong University Hospital from October 2020 to July 2021 were included in this study, all of whom underwent unilateral lateral rectus recession combined with a medial rectus resection in the same eye. Aberration parameters were measured 1 day before surgery and 1 week, 1 month, 3 months, and 6 months after surgery. Differences in the indicators at each time period were compared by analysis of variance (ANOVA) of repeated measures data for a single factor, and data were analyzed using SPSS 25.0 statistical application software. Results. 5 mm pupil diameter: the preoperative and postoperative RMS of total aberration showed statistically significant difference ( $P<0.01$ ). Postoperation test (Bonferroni method) and preoperative comparison at each period after surgery showed statistically significant differences between 6 months after surgery ( $P=0.002$ ) and preoperative comparison. The preoperative and postoperative comparison of RMS in LOAs was statistically significant ( $P<0.01$ ); postoperative test (Bonferroni method) and preoperative comparison showed that there were statistically significant differences between 1 week ( $P=0.033$ ) and 6 months ( $P=0.002$ ) after operation. The difference of RMS of defocus before and after operation was statistically significant ( $P<0.01$ ); postoperation test (Bonferroni method) and preoperative comparison showed that there was statistically significant difference between 6 months after operation ( $P=0.007$ ) and preoperative comparison. There was statistically significant difference in preoperative and postoperative RMS of HOAs ( $P=0.013$ ). Postoperative test (Bonferroni method) and preoperative comparison showed that there was statistically significant difference 6 months after surgery ( $P=0.03$ ). The RMS of secondary astigmatism showed a statistically significant difference before and after operation ( $P=0.001$ ), and the postoperation test (Bonferroni method) showed a statistically significant difference 6 months after operation ( $P=0.002$ ). In 5 mm pupil diameter, the preoperative and postoperative RMS of total aberration showed statistically significant difference ( $P<0.01$ ), postoperative test (Bonferroni method) was used to compare each period after surgery with that before surgery, and there were statistically significant differences between 1 week after surgery ( $P=0.034$ ), 3 months after surgery ( $P=0.033$ ), and 6 months after surgery ( $P=0.003$ ). The preoperative and postoperative comparison of RMS in LOAs was statistically significant ( $P<0.01$ ), postoperative test (Bonferroni method) was used to compare each period after surgery with that before surgery, and there were statistically significant differences between 1 week after surgery ( $P=0.04$ ), 3 months after surgery ( $P=0.034$ ), and 6 months after surgery ( $P=0.004$ ). The difference of RMS of defocus before and after surgery was statistically significant ( $P=0.002$ ), and the comparison between postoperation test (Bonferroni method) and preoperation showed that the difference was statistically significant 6 months after surgery ( $P=0.027$ ). The RMS of astigmatism showed statistically significant difference before and after operation ( $P=0.002$ ), and the postoperation test (Bonferroni method) showed statistically significant difference between 6 months after operation ( $P=0.009$ ) and before operation. Conclusion. We found that horizontal rectus surgery had a transient effect on LOAs and almost no effect on HOAs. Long-term follow-up is recommended after strabismus surgery to observe eye position and binocular visual function. Because of the high prevalence of strabismus in adolescents, long-term observation of the eye axis and aberration is recommended.