| Part 1: Relationship between post-exercise changes in the lens and Schlemm's canal: a swept-source optical coherence tomography studyPurpose: To observe post-exercise changes in the lens and Schlemm's canal(SC)in healthy individuals using swept-source optical coherence tomography(SS-OCT).Methods: Thirty-five healthy,young individuals were recruited and performed aerobic exercise by jogging for 20 minutes.The SC area,SC perimeter,trabecular meshwork(TM)length,TM thickness,lens vault(LV)and lens thickness(LT)were assessed by SS-OCT before and after exercise.Results: Following aerobic exercise,SC area(4260.85 ± 1476.02 vs.5158.24 ± 1527.42 ?m2,p < 0.001),SC perimeter(349.21 ± 62.22 vs.391.24 ± 71.77 ?m,p < 0.001),TM length(781.16 ± 114.83 vs.816.46 ± 121.26 ?m,p < 0.001),and TM thickness(111.52 ± 19.30 vs.116.96 ± 17.57 ?m,p = 0.004)increased significantly,while LV(-0.134 ± 0.198 vs.-0.195 ± 0.198 mm,p < 0.001)decreased significantly and LT showed no significant post-exercise changes(3.86 ± 0.32 vs.3.85 ± 0.32 mm,p = 0.801).Moreover,post-exercise changes in SC area were significantly associated with post-exercise changes in LV(? =-6487.83;p = 0.040).Conclusions: Aerobic exercise induces both backward axial displacement of the lens and SC expansion.This backward axial displacement of the lens could be an important causative factor of the post-exercise SC expansion via the lens-zonular-ciliotrabecular vector and the connecting fibrils between ciliary body and SC.Part 2: Post-exercise Recovery of Schlemm's Canal and Intraocular Pressure in Healthy Individuals: An Observational Study Using Swept-source Optical Coherence TomographyPurpose: To observe the recovery process of post-exercise Schlemm's canal(SC)and intraocular pressure(IOP)in healthy individuals.Methods: Twenty healthy individuals were recruited.SC and IOP were evaluated before exercise,immediately after exercise,and 15,30,and 60 minutes after exercise.Superior,inferior,nasal,and temporal SC quadrants were evaluated using swept-source optical coherence tomography(SS-OCT).Results: Average SC area(3726.81 ± 1167.06 vs.4660.57 ± 1284.82 ?m2)and perimeter(324.11 ± 58.95 vs.367.19 ± 73.34 ?m)increased and IOP(14.02 ± 2.33 vs.11.65 ± 1.90 mm Hg)decreased significantly during exercise(all p < 0.001).After exercise,both SC and IOP recovered to pre-exercise values and the recovery time for post-exercise SC dimensions(15 minutes)was shorter than that for post-exercise IOP(60 minutes).After adjusting for age,gender,axial length,central corneal thickness and spherical equivalent,post-exercise changes in SC dimensions were not significantly associated with post-exercise changes in IOP compared with pre-exercise values(all p > 0.05).There were no significant differences in the observable SC proportion before and after exercise(all p > 0.05).Conclusions: The exercise-induced SC expansion and IOP reduction could recover to pre-exercise values after exercise,and SC recovered to pre-exercise values ahead of IOP.Moreover,SC might be regulated by the sympathetic nerves and could be an important causative factor of changes in IOP during and after exercise.Part 3: Influence of exercise on the structure of the anterior chamber of the eyePurpose: To measure changes in anterior chamber structure before and after exercise in healthy individuals using anterior segment optical coherence tomography(ASOCT).Methods: Thirty-two healthy young individuals performed jogging for 20 minutes.Eye blinking rate was recorded during rest and exercise.The anterior chamber angle(ACA),angle opening distance at 500?m from the scleral spur(AOD500),trabecular-iris space area at 500?m from the scleral spur(TISA500),iris concavity(IC),iris concavity ratio(CR),iris thickness at 750?m from the scleral spur(IT750),anterior chamber depth(ACD),anterior chamber width(ACW),pupil diameter(PD),intraocular pressure,blood pressure and heart rate were recorded before and after exercise.ACA,AOD500,TISA500,IC,IT750,ACD,ACW,and PD were measured with ASOCT.Results: Compared with rest,the blinking rate during exercise did not change significantly(13.04 ± 5.80 vs.13.52 ± 5.87 blinks/min,P = 0.645).The average IOP(15.4 ± 2.4 vs.12.4 ± 2.1 mm Hg),ACA(35.96 ± 11.35 vs.40.25 ± 12.64 degrees),AOD500(0.800 ± 0.348 vs.0.942 ± 0.387 mm),TISA500(0.308 ± 0.155 vs.0.374 ± 0.193 mm2),IC(-0.078 ± 0.148 vs.-0.153 ± 0.159 mm)and CR(-0.027 ± 0.050 vs.-0.054 ± 0.056)changed significantly(all P < 0.001),while the average IT750(0.463±0.084 vs.0.465 ± 0.086 mm;P = 0.492),ACD(3.171 ± 0.229 vs.3.175 ± 0.238 mm;P = 0.543)and ACW(11.768 ± 0.377 vs.11.755 ± 0.378 mm;P =0.122)showed no significant change after exercise.Conclusions: The blinking rate did not change significantly during exercise,while ACA,AOD500,and TISA500 increased after exercise.Exercise also induced or increased iris concavity.These changes in anterior chamber structure were only associated with exercise,but not with the post-exercise change in PD or IOP. |
PDF Full Text Request