Effects of baffie and intraocular pressure on aerosols generated in the noncontact tonometer measurement during COVID-19

AIM: To investigate the effects of baffle and intraocular pressure(IOP) on the aerosols generated in the noncontact tonometer(NCT) measurement and provide recommendations for the standardized use of the NCT during coronavirus disease 2019(COVID-19). METHODS: This clinical trial included 252 subjects(312 eyes) in The Eye Hospital, Wenzhou Medical University from March 7, 2020, to March 28, 2020. Sixty subjects(120 eyes) with normal IOP were divided into two groups. One group used an NCT without a baffle, another group used an NCT with a baffle. Another 192 subjects(192 eyes) were divided into four groups: Group A;(without a baffle+normal IOP), Group A;(without a baffle+high IOP), Group B;(with a baffle+normal IOP) and Group B;(with a baffle+high IOP). Particulate matter(PM) 2.5 and PM10 generated by all subjects were quantified during the NCT measurement. The IOP values were recorded simultaneously. Effects of baffle and IOP on aerosols generated during the NCT measurement were analyzed.RESULTS: In the normal eye group with a baffle, the aerosol density decreased in a wave-like shape near the NCT with the increase in the number of people measured for IOP, demonstrating no cumulative effect. However, in the normal eye group without a baffle, there was a cumulative effect. PM2.5 and PM10 in Group A;were higher than Group A;(both P<0.001). The PM2.5 and PM10 in Group B;were higher than Group B;(P<0.01, P<0.001 respectively). The PM10 of Group B;was lower than Group A;(P<0.01). PM2.5 in Group B;were lower than Group A;(P<0.01). The median of per capita PM2.5 and PM10 in the combined Group A;+A;were 0.80 and 1.10 μg/m;respectively, which were higher than 0.20 and 0.60 μg/m;in the combined Group B;+B;(both P<0.01). The median of per capita PM2.5 and PM10 in the combined Group A;+B;were 0.10 and 0.20 μg/m;respectively, which were lower than 1.30 and 1.70 μg/m;in the combined Group A;+B;(both P<0.001).CONCLUSION: More aerosols could be generated in patients with high IOP. After the NCT is equipped with a baffle, per capita aerosol density generated decreased significantly near the NCT;And with the increase in the number of people measured for IOP, the aerosols gradually dissipated near the NCT, demonstrating no cumulative effect. Therefore, it is suggested that the NCT should be equipped with a baffle, especially for patients with high IOP.

Elementary school comprehensive intervention and myopia development:the Wenzhou Epidemiology of Refraction Error Study

AIM:To investigate the effects of school-basedcomprehensive intervention on myopia development inelementary school children.METHODS:As a part of the Wenzhou Epidemiologyof Refraction Error Study,there were 1524 participatingelementary students(730 girls,47.9%)in grades 1 to3 from three campuses of one school,aged 7.3±0.9y,who were examined twice every year for a 2.5y follow upperiod.Comprehensive intervention and other reminderswere given at school every semester for the interventiongroup.The control group did not receive comprehensiveintervention and did not have reminders of it.RESULTS:There were 651 students in the interventiongroup[mean age 7.3±0.9y;294(45.2%)girls]and 737students in the control group[mean age 7.2±0.9y;346(46.9%)girls].Overall mean myopia progression duringthe 2.5y follow-up was-0.49±1.04 diopters(D)in theintervention group and-0.65±1.08 D in the control group(P=0.004).The majority that not get myopia at baselinespherical equivalent(SE≤-1.0 D).Their mean myopiaprogression during the 2.5y follow-up was-0.37±0.89 Din the intervention group and-0.51±0.93 D in the controlgroup(27.5%reduction,P=0.009);Overall,mean axiallength elongation was less in the intervention group(0.56±0.32 mm)than in the control group(0.61±0.38 mm,10.5%reduction,P=0.009).The percentage of close reading distance(<30 cm)in the intervention group was less than in the control group(73.4%vs 76.2%,P<0.001),the percentage of everyday perform eye exercises in the intervention group was more than in the control group(27.8%vs 20.7%,P<0.001)30mo later.CONCLUSION:The comprehensive intervention program at elementary school has a significant alleviating effect on myopia progression for children during the 2.5y follow-up,especially for those non-myopia at baseline.