Clinical Observation On Clear Lens Phacoemulsification In The Treatment Of Early Angle Closure Glaucoma

IntroductionPrimary angle closure glaucoma(PACG)is a kind of glaucoma in which the anterior chamber angle is mechanically blocked by the peripheral iris tissue in susceptible individuals with abnormal anatomical structure,resulting in blocked aqueous humor outflow and elevated intraocular pressure.It is the primary type of glaucoma in China.The mechanism of angle closure in PACG is caused by pupil block,plateau iris,lens block,ciliary ring block,choroidal bulge and so on.Lens plays an important role in the pathogenesis of PACG.Phacoemulsification in the treatment of early angle closure glaucoma is to solve the problem from the pathogenesis,open the angle,reduce intraocular pressure.In this paper,the changes of intraocular pressure,visual acuity and anterior segment anatomy after clear lens extraction(CLE)and peripheral iridectomy(SPI)are compared and analyzed,which is helpful to better understand the clinical effect of transparent lens phacoemulsification in the treatment of early PACG.ObjectiveTo observe the clinical effect of transparent lens phacoemulsification combined with intraocular lens implantation in the treatment of early primary angle-closure glaucoma.MethodsA prospective case-control study was used.The clinical data of 68 cases(84 eyes)of patients diagnosed with early PACG and corrected visual acuity>0.5 treated in the First Affiliated Hospital of Zhengzhou University from Sep.2018 to Jan.2020 were collected,aged 50 to 63 years old,the average(55.83±3.85)years of age,including 33 males(38 eyes)and 35 females(46 eyes).All patients were randomly divided into two groups:32 cases(42 eyes)in group A received transparent lens phacoemulsification,with an average age of(56.31±3.69)years;36 cases(42 eyes)in group B received iridectomy,with an average age of(55.36±4.00)years,all operations were performed by the same mature ophthalmologist.The patients were followed up for 6 months.Follow-up examinations are intraocular pressure,visual acuity,anterior chamber depth(ACD),angle opening distance 500(AOD500),trabecular iris angle(TIA)and angle recess area(ARA).Results1.Intraocular pressure:The intraocular pressure between group A and group B without drug treatment before operation was compared,and the difference was not statistically significant(t=0.282,P=0.780);in group A and B the mean intraocular pressure decreased to normal at each time point after operation,and the difference was statistically significant compared with that before operation(group A:F=24.724,P<0.001;group B:F=8.316,P<0.001);the differences between the two groups were statistically significant at 1 day,1 month,3 months and 6 months after operation(t=-2.119,-2.238,-3.778,-2.417;P=0.040,0.031,0.001,0.020).2.Visual acuity:Preoperative corrected visual acuity comparison between group A and group B showed no statistical significance(t=-0.089,P=0.929);in group A,visual acuity at preoperative,postoperative 1 month and 6 months were not significantly different(F=0.310,P=0.734);the visual acuity at preoperative,postoperative 1month and 6months in group B were compared,the difference was statistically significant(F=4.578,P=0.016);after pairwise comparison in group B,there was no significant difference between preoperative and postoperative 1month(P=0.948),visual acuity 6 months after operation was lower than 1 month after operation(P=0.004).3.Anterior chamber depth(ACD):There was no difference in preoperative ACD between group A and group B(t=-0.307,P=0.760);the ACD was deeper 1 month and 6 months after surgery than that before surgery in each group,and the difference was statistically significant(group A:F=747.639,P<0.001;group B:F=7.053,P<0.05);the ACD of group A was deeper than that of group B at 1 month and 6 months after operation,and the difference was statistically significant(t=22.820,28.736,all P<0.001).4.Angle open distance 500(AOD500),Trabecular iris angle(TIA),Angle recess area(ARA):There was no significant difference in preoperative AOD500,TIA and ARA between the two groups(t=-0.191,-0.225,0.062;P=0.850,0.823,0.950);AOD500,TIA and ARA increased at 1 month and 6 months after operation compared with those before surgery in each group(all P<0.001);AOD500,TIA and ARA in group A were all higher than those in group B at 1 month and 6 months after operation,the difference was statistically significant(one month after operation:t=3.833,3.963,2.703;all P<0.05;6 months after operation:t=4.528,5.306,3.369;all P<0.05)5.Complications and treatment:In group A,5 eyes(11.9%)had mild corneal edema after phacoemulsification,and the cornea was transparent after 3 days of 50%hypertonic glucose,one eye(2.4%)had poor intraocular pressure control at 1 day after operation t(>21mmHg),and the IOP decreased to normal after brinzolamide eye drops;In group B,intraocular pressure increased(>21mmHg)in 5 eyes(11.9%)during the follow-up period after surgical peripheral iridectomy,among them,3 eyes(7.1%)with cataract underwent phacoemulsification combined with intraocular lens implantation 6 months after operation,and the remaining 2 eyes(4.8%)were treated with brinzolamide eye drops,and the intraocular pressure decreased to normalConclusion1.Compared with peripheral iridectomy,clear lens phacoemulsification can stabilize intraocular pressure,deepen anterior chamber and open anterior chamber angle more significantly.2.Transparent crystal phacoemulsification combined with intraocular lens implantation is effective in the treatment of early primary angle-closure glaucoma without cataract.