Observation seasonal variation of intraocular pressure in young healthy volunteers

AIM:To investigate fluctuation of intraocular pressure(IOP)and seasonal variation of 24-hour IOP during one year in healthy participantsMETHODS:Totally 13 young healthy volunteers participated in this study.IOP was measured with Canon TX-20 at about 8:00-9:00 a.m.from Monday to Friday every week for a whole year.They also underwent 24-hour IOP examination every three months.Blood pressure,heart rate,temperature,humidity,atmosphere pressure,sunshine duration and other environment parameters were recorded.RESULTS:The yearly fluctuation curve showed IOP in the summer months were lower than other seasons.In the multivariable generalized estimating equation analysis,IOP had a negative correlation with both temperature and sunshine duration(P<0.05).There also was a seasonal effect on 24-hour IOP.However,all intraclass correlation coefficients values of minimum,maximum and average of the 24-hour IOP and each individual IOP were less than 0.30.CONCLUSION:IOP is trend to be higher in cold days than warm days.IOP have negative association with both environmental temperature and duration of sunshine.On a season-to-season basis,24-hour IOP is not highly reproducible in healthy volunteers.

Association of peripheral anterior synechia,intraocular pressure,and glaucomatous optic neuropathy in primary angle-closure diseases

AIM:To investigate the association of peripheral anterior synechiae(PAS)with intraocular pressure(IOP)and glaucomatous optic neuropathy(GON)in primary angle closure(PAC)and primary angle-closure glaucoma(PACG).METHODS:Totally 355 eyes(238 PAC and 117 PACG)of 181 patients were included in this retrospective analysis of baseline data from a randomized clinical trial.All patients had undergone a comprehensive ophthalmic examination.The extent of PAS in clock hours as determined on gonioscopy was documented.The independent effect of the extent of PAS on IOP and the prevalence of GON were determined using multivariable generalized estimating equation(GEE)models.RESULTS:The frequency of GON increased with the extent of PAS and a higher IOP.PAS were more extensive(8 vs 1 clock hour,P<0.001)and IOP higher(28.01 vs 18.00 mm Hg,P<0.001)in PACG compared to PAC.The prevalence of GON among the PAS quartiles were 10.2%(PAS<0.5 clock hours),16.9%(PAS≥0.5 and PAS<3 clock hours),29.6%(PAS≥3 and PAS<7 clock hours),and 74.4%(PAS≥7 clock hours),respectively.After adjusting for IOP,age,gender,spherical equivalent,average Shaffer score and number of medications,the odds ratio(OR)for GON was 4.4(95%CI:1.5-13.0;P=0.007)with PAS≥3 clock hours and 13.8(95%CI:4.3-43.6;P<0.001)with PAS≥7 clock hours as compared to eyes with PAS<0.5 clock hours.The frequency of GON increased linearly with the extent of PAS.Extent of PAS was also associated with higher IOP.Eyes with both PAS≥6 clock hours and IOP≥21 mm Hg had the highest risk of GON compared to eyes with both PAS<6 clock hours and IOP<21 mm Hg(OR=18.0,95%CI:7.5-43.4;P<0.001).CONCLUSION:The extent of PAS in PAC and PACG is an important predictor of higher IOP and is linearly associated with GON independent of IOP,suggesting other factors related to PAS formation may be involved in the development of GON in PACG.

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.