Measuring changes in Schlemm’s canal and trabecular meshwork in different accommodation states in myopia children: an observational study

Abstract Purpose: Studies were designed to evaluate changes in the size of the Schlemm's Canal (SC) and trabecular meshwork(TM) during accommodation stimuli and cycloplegia states in myopic children. Methods: 34 children were enrolled. A -6D accommodation stimulus was achieved by looking at an optotype through a mirror. Cycloplegia state was induced with 1% tropicamide. Two states were confirmed by measuring the central lens thickness（CLT）, the anterior chamber depth and the pupil diameter. The size of the Schlemm's Canal (SC) and Trabecular Meshwork(TM) was measured using swept-source optical coherence tomography. And the associations between the change of the SC and the CLT were analyzed. Results: When compared with the relaxation state, under -6D accommodation stimuli, the size of SC increased significantly: the SC area (SCA) amplified from 6371±2517μm2 to 7824±2727 μm2; the SC length (SCL) from 249±10 μm to 295±12 μm, and SC width (SCW) from 27±9 μm to 31±8 μm. Under cycloplegia state, the SCA reduced to 5009±2028 μm2; the SCL to 212±μm and the SCW to 22±5 μm. In addition, the changed areas of SCA (r=0. 35; P=0.0007), SCL (r=0. 251; P=0.0172), and SCW (r=0. 253; P=0.016) were significantly correlated with the change in CLT. However, the size of TM did not change substantially when compared with the relaxation state. Only the TM length (TML) increased from 562±45μm to 587±47μm after -6D accommodation stimulus. Conclusion: SC size enlarges after -6D accommodation stimuli and shrinks under cycloplegia. However, for TM, only the TM length increase under accommodation stimulus state. KEYWORDS: Schlemm’s Canal, Trabecular Meshwork, accommodatio

Dynamic Changes of Scleral Spur Length In Different Accommodation States

Abstract This study aimed to evaluate the scleral spur length in response to different accommodation stimuli states, as well as the correlation with Schlemm’s canal and trabecular meshwork. 74 children were recruited for this study. The 0D, -4D, and − 8.0 D accommodation state was stimulated by looking at a variable distance optotype. The ciliary muscle, scleral spur, Schlemm’s canal, and trabecular meshwork were imaged by swept-source optical coherence tomography. The scleral spur length increased with accommodation stimulation (p &lt; 0.05). Method I was 127.97 ± 20.32 µm, 138.29 ± 20.11 µm, and 150.73 ± 21.75 µm at 0D, -4D and − 8D, respectively. Method II was 158.15 ± 19.97 µm, 168.47 ± 18.72 µm, and 179.79 ± 20.83 µm at 0D, -4D and − 8D, respectively. Method III was 221.56 ± 30.74 µm, 234.99 ± 30.11 µm, and 250.09 ± 29.87 µm at 0D, -4D and − 8D, respectively. Method III had the largest areas under ROC curves (0.798, 95% CI 0.721–0.875). Moreover, ciliary muscle 1, Schlemm’s canal, and trabecular meshwork length were significantly correlated with SSL (Method III) (p &lt; 0.05). These findings suggest that the contractile ability and compliance of the scleral spur play an important role in maintaining the morphology of the SC. Moreover, the force of accommodation regulates the SC size by increasing the length of SS.</jats:p

Dynamic changes of scleral spur length in different accommodation stimuli states

AbstractThis study aimed to evaluate the scleral spur length (SSL) in response to different accommodation stimuli states, as well as the correlation with Schlemm’s canal (SC) and trabecular meshwork (TM). 74 children were recruited for this study. The 0D, − 4D, and − 8.0 D accommodation stimuli state was achieved by looking at a variable distance optotype. The ciliary muscle (CM), scleral spur (SS), SC, and TM were imaged by swept-source optical coherence tomography. The SSL (Method III) increased significantly from 221.56 ± 30.74 μm at base state to 234.99 ± 30.11 μm at − 4D accommodation stimuli state (p = 0.028) and increased to 250.09 ± 29.87 μm at − 8D accommodation stimuli state (p = 0.011). Method III had the largest areas under receiver operating characteristic (ROC) curves (0.798, 95% CI 0.721–0.875). Moreover, CM 1, SC, and trabecular meshwork length (TML) were significantly correlated with SSL (Method III) (p &lt; 0.05). These findings suggest that the contractile ability and compliance of the SS play an important role in maintaining the morphology of the SC. Moreover, the force of accommodation regulates the SC size by increasing the length of SS.</jats:p