Dark-light change of iris parameters and related factors among American Caucasians, American Chinese, and Mainland Chinese

The effect of smartphone uses on gait and obstacle collision during walking

OBJECTIVE

This study aims to investigate the impact of obstacle collision according to the presence or absence of light and the change of gait when using smartphones while walking.

STUDY DESIGN/SETTING

A cross-sectional study.

SUBJECTS

24 healthy young people.

METHODS

Obstacle collision was measured in participants as they passed through four obstacles at different heights (eyes, waist, knees, ankle level), with the lights turned on. The same was measured with the lights turned off. To measure spatiotemporal variables, GAITRite was used. Obstacle collision was used in the frequency analysis, and the spatiotemporal variables were assessed using one-way ANOVA test. The post-hoc Tukey's test was used to detect spatiotemporal variables differences (p < 0.05).

RESULTS

Obstacle collision was the highest at eye level when playing games and messaging while walking. It was also higher when lights were turned off rather than when lights were on. Gait function decreased while walking when messaging or playing games on a smartphone as compared to when walking without a smartphone.

CONCLUSION

Understanding the collision rate of various obstacles encountered when using smartphones while walking could contribute to the prevention of accidents.

Association of Angle Width With Progression of Normal-Tension Glaucoma: A Minimum 7-Year Follow-up Study

Importance

Glaucoma has been dichotomically classified as open or closed angle, and accordingly, distinct therapies have been administered. In this study, the issue of narrow-angle normal-tension glaucoma (NTG), which may be an intermediate-stage or hybrid-stage disease entity, was addressed.

Objective

To determine whether anterior chamber (AC) angle width plays any role in NTG progression.

Design, Setting, and Participants

Retrospective analysis of prospectively collected data at Seoul National University Hospital between January 2004 and December 2009. Fifty-two eyes of narrow-angle NTG and 52 wide-angle NTG eyes matched for age, untreated intraocular pressure, and mean deviation of visual field. Nonindentation gonioscopy was used to grade AC angles: narrow angle was defined as a partially invisible (invisible in ≥90° and <180°) pigmented posterior trabecular meshwork, and wide angle was defined as a fully visible pigmented posterior trabecular meshwork. Data were analyzed in September 2017.

Main Outcomes and Measures

Optic disc/retinal nerve fiber layer defect and visual field progression.

Results

Of the narrow-angle NTG cohort, the mean (SD) age was 49.5 (9.1) years and 15 individuals (28.8%) were women; of the wide-angle NTG cohort, the mean (SD) age was 48.7 (9.5) years and 19 (36.5%) were women. All participants were Korean. Over the course of the mean (SD) 7.6 (0.4)-year follow-up period, 25 of 52 narrow-angle eyes (48.1%) and 13 of 52 wide-angle eyes (25.0%) showed structural progression (odds ratio [OR], 2.78; 95% CI, 1.21-6.37; P = .02). Meanwhile, 21 of 52 narrow-angle eyes (40.3%) and 9 of 52 wide-angle eyes (17.3%) showed functional progression (OR, 3.24; 95% CI, 1.31-8.00; P = .009). The cumulative probability of both structural and functional progression was significantly greater in the narrow-angle than in the wide-angle group (mean [SD] 5-year survival rates, 0.56 [0.07] vs 0.83 [0.05]; P = .006 and 0.60 [0.07] vs 0.87 [0.05]; P = .007, respectively). The baseline diurnal intraocular pressure's SD was approximately 1.38-times greater in the narrow-angle than in the wide-angle group (1.8 [0.6] vs 1.3 [0.3] mm Hg; mean difference, 0.52; 95% CI, 0.32-0.72; P < .001). For the follow-up intraocular pressure fluctuation, the narrow-angle group showed an approximately 1.75-times greater SD (2.1 [0.5] vs 1.2 [0.3] mm Hg; mean difference, 0.93; 95% CI, 0.77-1.09; P < .001).

Conclusions and Relevance

Narrow-angle NTG showed a greater probability of disease progression than did wide-angle NTG. Further studies determining whether augmented or differentiated treatment strategies would be beneficial for patients with narrow-angle NTG are warranted.

Changes in intraocular pressure during reading or writing on smartphones in patients with normal-tension glaucoma

BACKGROUND/AIMS

To investigate (1) the effect of reading or writing on a smartphone in terms of intraocular pressure (IOP) change in eyes with glaucoma, and (2) to determine whether previous glaucoma filtering surgery can affect IOP fluctuation during such work.

METHODS

Forty eyes of 40 medically well IOP-controlled normal-tension glaucoma (NTG) patients and 38 eyes of 38 NTG patients who had undergone successful trabeculectomy (TLE) were enrolled. The participants were instructed to read a sample text and to then type it on a smartphone under low-light [100 lux] conditions. Three IOP measurements were obtained: baseline; during smartphone work (5, 15 and 25 min); post-work (5 and 15 min).

RESULTS

Baseline IOP did not significantly differ between the two groups (medication group: 13.9±1.6 mm Hg; TLE group: 13.6±1.7 mm Hg; p=0.426). After 5 min of smartphone work, the medication group showed significantly elevated mean IOP (15.5±1.8 mm Hg;+11.5%; p<0.001), along with further increases over the course of 25 min (17.5±2.2 mm Hg;+25.9%; p<0.001). 5 min after halting work, IOP dropped below the baseline (13.1±1.7 mm Hg; p<0.001). For the TLE group, IOP also was elevated after 5 min (14.9±1.7 mm Hg;+9.4%; p<0.001); however, it did not show further increase over the course of 25 min of work (15.0±1.6 mm Hg;+10.3%). At 5 min after cessation of work, IOP had restored to the pre-work level (14.0±1.9 mm Hg;+2.8%; p=0.053).

CONCLUSION

Working on a smartphone under low-light condition can incur IOP elevation in treated NTG patients. However, among the participants in this study, IOP fluctuation was much smaller in those who had undergone TLE.

Anterior Segment Parameters of Filipino-Americans Compared to Chinese-Americans and Caucasian Americans Using Anterior Segment Optical Coherence Tomography

Purpose

We compare anterior segment characteristics of Filipino- versus Chinese- and Caucasian-Americans to describe the differences in risk factors among each ethnic group.

Methods

A cross-sectional study was conducted among Filipino, Chinese, and Caucasian subjects without glaucoma who underwent a standardized set of ocular examinations and anterior segment optical coherence tomography (Visante ASOCT) imaging. Zhongshan Angle Assessment Program (ZAAP) 4 was used for ASOCT image analysis. The following quantitative parameters wereobtained from ZAAP: (1) angle opening distance (AOD500, AOD750), angle recess area at 750 μm (ARA), and trabecular-iris space area at 500 and 750 μm (TISA500, TISA750); (2) iris parameters, including iris thickness at 750 μm from the scleral spur (IT750), iris area (IArea), iris curvature or convexity (ICurv), and pupil diameter; 3) anterior chamber parameters; and (4) lens vault.

Results

The Filipino (122 eyes), Chinese (121 eyes), and Caucasian (111 eyes) subject groups were similar in terms of demographic and clinical characteristics. We reported pairwise comparisons of Filipino parameter values to Chinese or Caucasian values, represented as B-coefficients and P values. In multivariate analysis, Filipinos had narrower angles than Caucasians (AOD750, TISA 500, TISA 750, ARA, P < 0.001). Filipinos had thicker and more convex irises than Caucasians (IT750, IT 2000, ICurv P < 0.003). Angle and iris parameters were similar overall for Filipino and Chinese.

Conclusions

Filipinos appear to have more convex and thicker irises, smaller lens vault and narrower angles compared to Caucasians. Filipino eyes closely resembled Chinese eyes with similar iris and angle parameters.

Translational Relevance

The anatomic angle parameters of Filipinos may contribute to angle closure risk among this population, thus ASOCT and thorough angle analysis is recommended in this population.

Intraocular pressure change during reading or writing on smartphone

Purpose

To investigate the effect of reading or writing on a smartphone in terms of intraocular pressure (IOP) changes.

Design

Prospective, comparative case series.

Participants

Thirty-nine (39) healthy young (age < 40) volunteers.

Methods

The participants were requested to conduct standardized work (i.e., read a sample text on single mobile device and subsequently type it on the same device) under daylight [300 lux] and low-light [100 lux] conditions independently on consecutive days. On each day, three sets of IOP measurements (total: 7) using a rebound tonometer (iCare PRO; Tiolat, Helsinki, Finland) were performed: (1) pre-work (baseline) [2 measurements], (2) during smartphone work [5, 15, and 25 minutes], and (3) post-work [5 and 15 minutes].

Main outcome measures

Changes in IOP at different check-out points.

Results

Under the daylight condition, the mean baseline IOP was 13.7 ± 1.8 mmHg, and the mean IOP increased after 5 minutes of work (14.1 ± 1.8 mmHg; +2.0 ± 1.9%; P < 0.001). When the smartphone work lasted for 15 minutes, the IOP showed a further significant increase (15.5 ± 1.7 mmHg; +12.9 ± 4.4%; P < 0.001), which persisted over the course of the 25 minutes of smartphone work (15.3 ± 1.8 mmHg; +11.1 ± 3.9%; P < 0.001); then, after stopping work for 5 minutes, the IOP was restored (13.9 ± 1.7 mmHg; +0.9 ± 2.1%; P = 0.220). Under the low-light condition, the mean IOP was significantly increased immediately after 5 minutes of smartphone work (from 13.9 ± 1.9 to 15.6 ± 1.8 mmHg; +12.1 ± 4.8%; P < 0.001); this IOP increase continued: 17.3 ± 1.9 [+24.7 ± 10.3%] at 15 minutes’ work, and 17.0 ± 1.7 mmHg [+23.1 ± 9.5%] at 25 minutes’ work (P < 0.001 at both check-out points). Five minutes after stopping the smartphone work, interestingly, the IOP significantly dropped, to a level even lower than that of the pre-work (12.8 ± 1.9 mmHg; -8.1 ± 3.0%; P < 0.001), and at post-work 15 minutes, the IOP returned to the baseline (13.9 ± 1.8 mmHg; -0.3 ± 2.6%; P = 0.360).

Conclusions

In healthy young subjects, reading or writing on smartphone significantly increased IOP, and the changes of IOP were faster and greater under the low-light condition. Smartphone users who are concerned about IOP fluctuation are advised to (1) take a break if they read or write on smartphone for more than 5 minutes, and (2) avoid using smartphones wherever possible in dark places.

Reliability of Ocular Aberration Measurements in Children with Moderate and Low Myopia under Scotopic Conditions

Purpose

To investigate the reliability of ocular aberration measurement in myopic children under scotopic conditions and to validate the mathematical Zernike pupil scaling-down technique.

Methods

Ocular aberrations of 45 myopic children were examined under scotopic conditions via iTrace aberrometer. The intra- and intersession repeatability was evaluated for both the measured values with the true pupil sizes and the estimated ones that were determined by scaling down the pupil sizes to the largest integer value across all measurements.

Results

The intra- and intersession difference of clinically measured aberration was generally insignificant, and the ICCs for each aberration component exhibited good to excellent reliability (ICCs > 0.4). Similar results were found for the estimated aberration using the scaling-down technique. Although the majority of the estimated Zernike components were comparable with the corresponding measured one, the estimated values of defocus, coma, and the corresponding total aberrations were found significantly smaller than the measured values (all P < 0.01).

Conclusions

The ocular aberration measurements in myopic children under the circumstances described are reliable. The scaling-down technique is a useful option for comparing the results obtained from different pupil sizes, but the estimated Zernike coefficients were not always comparable with the corresponding measured values.

The effect of internal fixation lamp on anterior chamber angle width measured by anterior segment optical coherence tomography

PURPOSE

To study the effect of the internal fixation lamp on anterior chamber width measured by anterior segment optical coherence tomography.

METHODS

In a prospective cross sectional observational study, consecutive 22 right eyes of 22 patients (4 men and 18 women) with suspected primary angle closure underwent swept source domain anterior segment optical coherence tomography (AS-OCT), (CASIA SS-1000, Tomey, Nagoya, Japan). Anterior chamber parameters of angle opening distance (AOD), trabecular-iris angle (TIA), angle recess area (ARA) at 500 or 750 µm from scleral spur and pupil diameter were measured by AS-OCT in a three-dimensional mode in 4 quadrants (superior, inferior, temporal and nasal) in dark room setting both with and without internal fixation lamp.

RESULTS

Anterior segment parameters of AOD 500 in superior, inferior and temporal quadrants, AOD 750 at superior and nasal, TIA 500 at superior, and inferior and TIA 750 at superior and nasal, and ARA 500 or 750 at superior and inferior with internal fixation lamp were greater and the pupil diameter was significantly (all P < 0.05, paired t test) smaller than when measured without fixation lamp.

CONCLUSIONS

Internal fixation lamp of the anterior segment OCT makes the pupil constrict and angle wider. When using AS-OCT with usual setting with internal fixation lamp on with eyes in which the anterior chamber angle is narrow but open, it is recommended that the internal fixation lamp be turned off to ensure a clear indication as to whether the angle is open or closed in the dark.

The Reliability, Validity, and Normative Data of Interpupillary Distance and Pupil Diameter Using Eye-Tracking Technology

Purpose

The purpose of this study was to determine the reliability of interpupillary distance (IPD) and pupil diameter (PD) measures using an infrared eye tracker and central point stimuli. Validity of the test compared to known clinical tools was determined, and normative data was established against which individuals can measure themselves.

Methods

Participants (416) across various demographics were examined for normative data. Of these, 50 were examined for reliability and validity. Validity for IPD measured the test (RightEye IPD/PD) against the PL850 Pupilometer and the Essilor Digital CRP. For PD, the test was measured against the Rosenbaum Pocket Vision Screener (RPVS). Reliability was analyzed with intraclass correlation coefficients (ICC) between trials with Cronbach's alpha (CA) and the standard error of measurement for each ICC. Convergent validity was investigated by calculating the bivariate correlation coefficient.

Results

Reliability results were strong (CA > 0.7) for all measures. High positive significant correlations were found between the RightEye IPD test and the PL850 Pupilometer (P < 0.001) and Essilor Digital CRP (P < 0.001) and for the RightEye PD test and the RPVS (P < 0.001).

Conclusions

Using infrared eye tracking and the RightEye IPD/PD test stimuli, reliable and accurate measures of IPD and PD were found. Results from normative data showed an adequate comparison for people with normal vision development.

Translational Relevance

Results revealed a central point of fixation may remove variability in examining PD reliably using infrared eye tracking when consistent environmental and experimental procedures are conducted.

New developments in anterior segment optical coherence tomography for glaucoma

PURPOSE OF REVIEW

The aim of the present review was to summarize the new developments in anterior segment optical coherence tomography (AS-OCT) for glaucoma.

RECENT FINDINGS

Recent years have demonstrated significant advances in the measurement of glaucoma through the use of AS-OCT. Furthermore, a more widespread use of AS-OCT in the clinical study of various glaucomas warrants review, which includes angel assessment, trabecular meshwork and Schlemm's canal assessment, and assessment of the filtering bleb and tube.

SUMMARY

AS-OCT was recently developed and has become a crucial tool in glaucoma clinical practice. AS-OCT is a noncontact imaging device that provides the detailed structure of the anterior part of the eyes. In this review, the author will discuss the various clinical applications of AS-OCT for glaucoma disease, such as angle assessment, trabecular meshwork and Schlemm's canal assessment, or assessment of the filtering bleb and tube.

Comparison of iris insertion classification among american caucasian and ethnic Chinese using ultrasound biomicroscopy

PURPOSE

To qualitatively classify and compare types of iris insertion among American Caucasians, American Chinese, and mainland Chinese.

METHODS

Prospective multicenter cross-sectional study. Sex- and age-matched Caucasian, American Chinese, and mainland Chinese cohorts were enrolled. Ultrasound biomicroscopy (UBM) images of the anterior chamber were acquired. Qualitative classification of iris insertion into basal, middle, and apical categories was performed. Proportions of each type of insertion were compared among racial groups. Multivariate logistic regression was carried out adjusting for potential confounders.

RESULTS

data from 117, 129, and 112 subjects were available for american caucasian, american chinese, and mainland chinese subjects, respectively. The most common type of iris insertion in the superior quadrant was basal insertion in both ethnic Chinese and Caucasians. In the inferior, nasal, and temporal quadrants, chinese showed significantly higher proportions of nonbasal insertion (P = 0.048, P 0.0001, P 0.0001, respectively). After adjusting for confounders, nonbasal insertion was significantly associated with Chinese ethnicity in nasal and temporal quadrants (nasal, OR: 3.1, temporal, OR: 4.8). Increasing proportions of nonbasal insertion were found with advancing age in both Chinese and Caucasians.

CONCLUSIONS

Chinese have significantly higher proportions of nonbasal iris insertion in the nasal and temporal quadrants when compared with Caucasians, even after adjusting for ASOCT-measured anterior segment biometry and iris characteristics. Longitudinal studies in patients who have PAC/PACG are needed to fully elucidate the relationship between iris insertion and angle closure development.