Study On The Relaxation Of Lens Suspensory Ligament In Different Diopters

Research purposes:To explore the difference of relaxation of lens suspensory ligament in different refractive states.Research methods:Sixty-seven adult myopia patients(130 eyes in total)admitted to the ophthalmology department of our hospital from June 2022 to January 2023 were included and divided into 4 groups,including 24 eyes in the emmetropia group,36 eyes in the low-grade myopia group(-0.5D～-3.0D),36 eyes in the moderate myopia group(-3.00D～-6.0D)and 34 eyes in the High myopia group(>-6.0D).All subjects underwent medical history collection,basic information recording and ophthalmic examinations,including visual acuity,intraocular pressure,computerized optometry,IOL-Master 500 measurement,optical coherence tomography(OCT),best-corrected visual acuity(BCVA),ultrasound biomicroscopy(UBM)and fundus examination under slit lamp.Anterior chamber depth(ACD)and eye axial length(AL)in the sitting position and clinostatism were measured for each participant with no lens suspension ligament abnormality under UBM examination.The difference of ACD in different body positions was recorded as range of lens motion(RLM).The differences of ocular biological parameters and RLM among groups were compared,and the differences of lens suspension ligament relaxation between different diopters groups were evaluated.Results:There were no significant differences in gender,age or IOP among the four groups(P=0.237,P=0.600,P=0.565).ACD was positively correlated with AL in low,moderate and high myopia groups(P<0.01,r=0.709;P=0.013,r=0.560;P=0.014,r=0.417);ACD was positively correlated with AL in low,moderate and high myopia groups(P<0.01,r=0.747;P=0.013,r=0.559;P=0.017,r=0.405).There was no statistical correlation between ACD and AL measured by various methods(P>0.05).The mean values of RLM in emmetropia,low,moderate and high myopia groups were 0.053±0.041mm,0.079±0.05mm,0.084±0.044mm and 0.112±0.063mm respectively,and the difference was statistically significant(P<0.05).There was statistical significance between the emmetropia group and the high myopia RLM group(P=0.018,P<0.05),while pairwise comparison among other groups had no statistical significance.After mydriasis,ACD of high myopia group and emmetropia group was significantly increase,difference was statistically significant,and there was no statistical difference in ACD changes between two groups.There was no significant difference in AL between high myopia group and emmetropia group before and after pupil dilation.The RLM of high myopia group(0.118±0.063mm)was higher than that of emmetropia group(0.064±0.059mm),the difference was statistically significant(P=0.032,P>0.05)Conclusion:1.There was a positive correlation between AL and ACD increase,but the correlation coefficients of different diopter groups were different;2.The mean value of RLM in the high myopia group was the highest,which showed a statistical difference compared with that in the emmetropia group.The lens suspended ligament in the high myopia group was the most loose;3.The change of ACD under different body positions measured by eye A-scan ultrasound has a reference value for evaluating the relaxation degree of minor loose lens suspension ligament.