Study On The Relaxation Of Lens Suspensory Ligament In Primary Angle Closure Disease

Glaucoma is currently the world’s first irreversible blindness disease.Primary angle-closure disease(PACD)is the main type of glaucoma in our country.Previous studies have suggested that the relaxation of the suspensory ligament may be involved in the pathogenesis of PACD.However,due to technical limitations,we cannot directly measure the suspension.In recent years,Pentacam has been widely used in clinical practice as a highly accurate digital imaging device.This non-contact measurement method can obtain the parameters of the anterior segment more accurately,objectively and conveniently,which is helpful for us to evaluate the suspensory ligament relaxation.This study analyzed the characteristics and changes of anterior chamber depth(ACD)in patients with different types of PACD under normal,dilated and miotic conditions,and indirectly reflected the suspensory ligament relaxation,in order to explore its role in the occurrence and development of primary angle closure diseases.Objective: 1.To explore the difference of anterior chamber depth and the deviation of the lens in patients with various types of primary angle closure diseases under normal pupil conditions;2.To explore the difference in relaxation of lens suspensory ligament of patients with different types of primary angle closure diseases.3.Explore the possible role of suspensory ligament relaxation in the pathogenesis of primary angle closure disease.Methods:Patients with primary angle closure disease who needed cataract or glaucoma-cataract combined surgery or who needed laser peripheral iridectomy were collected in the Department of Ophthalmology of the Second Hospital of Hebei Medical University from December 2019 to December2020.77 Example(105 eyes)including 21 patients(24 eyes)with suspected primary angle-closure suspects(PACS),18 patients(18 eyes)with acute primary angle-closure(APAC)patients,APAC contralateral eyes in 18 eyes,chronic primary angle-closure(CPAC)patients in 17 cases(17 eyes),and primary angle-closure glaucoma(PACG)in 21 patients(28 eyes).In addition,24 healthy patients(40 eyes)were collected in our hospital as a normal control group.All patients underwent relevant medical historycollection,including gender,age,etc.,concurrent ophthalmological examinations such as: vision,intraocular pressure,slit lamp microscope,direct ophthalmoscope,gonioscope,UBM,visual field,etc.,use Pentacam to scan the anterior segment,Obtain CACD and peri-ACD in 8 directions(upper,supratemporal,temporal,inferior,inferior,inferior,nasal,nasal,and supranasal)within a 3mm range under normal pupil conditions.Give the patients 3 drops of pilocarpine nitrate eye drops.The interval was 5 minutes,and the Pentacam examination was repeated after 30 minutes to obtain CACD in miotic state.Patients with PACD were given 3 drops of compound tropikamide eye drops before undergoing cataract or glaucoma-cataract combined surgery at an interval of 5 minutes.Repeat the Pentacam examination 30 minutes later to obtain CACD and 8directions of peri-ACD in mydriatic state.PACD patients undergoing laser peripheral iridectomy,underwent Pentacam examination prior to the normal pupil state,and after laser peripheral iridectomy,the anterior chamber depth and the CACD after miosis were collected again in 9 directions under normal pupil state and mydriatic state.When comparing the anterior chamber depth under normal pupils in each group,use the data collected without laser peripheral iridectomy.When comparing the changes in the anterior chamber depth after miotic mydriasis in each group,select the depth of the anterior chamber when the pupils are normal after laser peripheral iridectomy.The depth of the anterior chamber and its changes in each group were analyzed and studied.Results:1.Comparison of the average and extreme values of peri-ACD in each group under normal pupil conditionsNormal control group,PACS group,APAC group,CPAC group,PACG group had different peri-ACD averages in 8 directions,and the results were statistically significant(P<0.001).The APAC group had the smallest average peri-ACD in all directions,which was different from the other four groups.The comparisons were statistically significant(P<0.05).The average value of peri-ACD in all positions of the normal control group was the largest,which was statistically significant compared with the other four groups(P<0.05).There was no significant difference in the mean value of peri-ACD in each direction among the three groups of PACS,CPAC and PACG(all P>0.05).The APAC group had the largest range value,which was statistically significant compared with the other four groups(all P<0.05).The difference of range between the other four groups was not statistically significant(all P>0.05).2.Comparison of the mean values of △peri-ACD in each group after mydriasisAfter mydriasis,the 8 directions of the peripheral anterior chamber in the five groups were deeper than before.After mydriasis,the average value of△peri-ACD in each of the PACD groups was significantly lower than that of the normal control group(all P<0.05).The APAC group was dilated The mean value of △peri-ACD was the smallest in the posterior positions,and was statisticallydifferent from the other four groups(all P<0.05).The pairwise comparisons among the three groups of PACS,CPAC and PACG were not statistically significant(all P>0.05).3.Comparison of five groups of △CACD after mioticAfter miosis,the central anterior chamber depth of the five groups became shallower than before,the APAC group △CACD was smaller than the other four groups,the difference was statistically significant(all P <0.05),the other four groups △CACD compared with no statistics Significance(all P>0.05).4.Comparison of △CACD after miotic and after mydriasis in each groupThe difference of CACD in each group of PACD under miotic and dilated conditions was significantly smaller than that of the normal control group(all P<0.05).The △CACD of the APAC group was the smallest after miotic and dilated,and it was statistically different from the other four groups(all P<0.01).The pairwise comparisons among the three groups of PACS,CPAC and PACG were not statistically significant(all P>0.05).5.Comparison of the mean and extreme difference of peri-ACD in each position between the APAC group and the contralateral eye group under normal pupilsThe average value of peri-ACD in the 8 directions of the APAC group was smaller than that of the contralateral eye group.The comparison of the two groups of 8 directions of peri-ACD was different,and the results were statistically significant(all P<0.05).The range of the APAC group was larger Compared with the contralateral eye group,the difference was statistically significant(P<0.05).6.Comparison of the mean values of △peri-ACD in each position between the APAC group and the contralateral eye group after mydriasisAfter mydriasis,the peripheral anterior chamber depth in 8 directions of the two groups were deeper than before.The change of peripheral anterior chamber depth after mydriasis in the APAC group was smaller than that of the contralateral eye group.The results were statistically significant(P<0.05).7.Comparison of △CACD between APAC group and contralateral eye group after mioticThe depth of the central anterior chamber of the two groups became shallower after miosis.The change of the depth of the central anterior chamber of the APAC group was smaller than that of the contralateral eye group.The result was statistically significant(P<0.05).8.Binary logistic regression analysis of risk factors for acute onset of primary angle closure disease△CACD after mydriasis and miosis is related to the acute onset of primary angle closure disease,which is statistically significant,in the meanwhile the OR value is 0.248(P<0.001).There was no statistically significant correlation between age or gender and the acute onset of primary angle closure disease(both P>0.05).9.Prediction of △CACD after mydriasis and miosis for acute onset of primary angle closure diseaseThe receiver operating curve(ROC)results showed that the area under the curve was 0.906,95% CI [0.802-0.967],greater than 0.5 and statistically significant(P <0.001),the predictive sensitivity was 0.879,and the specificity was 0.885.Conclusions:1.When the pupils are normal,mean value of the peripheral anterior chamber depth of each PACD group is smaller than that of the normal control group,and mean value of the peripheral anterior chamber depth of the APAC group is smaller than that of the PACS group,CPAC group,PACG group and the contralateral eye group.2.The tension of the lens suspensory ligament in each position of the PACD group,the APAC contralateral eye group and the normal control group are different,and the tension of the lens suspensory ligament in each position of the APAC group has the largest difference.3.The lens suspensory ligament was loose in each group of PACD.The lens suspensory ligament of APAC group was the most loose,and the degree of looseness was greater than that of the contralateral eye group.Relaxation of the lens suspensory ligament may not be related to intraocular pressure fluctuations.4.Lens suspensory ligament relaxation is a risk factor for the acute onset of primary angle closure disease.5.Relaxation of the lens suspensory ligament can predict the acute onset of primary angle closure disease.