Changes Of Anterior Segment Parameters In The Combined Or Staged Vitrectomy And Cataract Surgery

Patients with cataract and fundus disease can be treated in one surgery which is the combined of pars plana vitrectomy(PPV)and cataract surgery.This procedure has the advantages including a more sufficient exposure of the surgical field,early postoperatively improved visual acuity,and avoidance of secondary surgery.But compared with staged surgery,anterior and posterior segment surgery has higher requirements of equipment and technology,and postoperative complications are more diversified.Refractive error is often reported as one of the most common complication.The exact measurement of anterior segment parameters such as anterior chamber depth(ACD)and keratometry(K)are of major importance for the implantation of intraocular lens(IOL)calculation.The variables of the calculation,as well as the evaluation index of postoperative effective lens position(ELP),have a profound impact on postoperative refractive error.This study will compare the anterior segmental parameters in the combined surgery and staged surgery.And observe silicone oil tamponade(SOT)and filtered air tamponade(FAT)on the anterior segment of the eye in the two surgical procedures,respectively.We also evaluated effects of the lens extraction during the PPV on the postoperative intraocular pressure(IOP)and the anterior chamber angle(ACA).Our study is designed to verify the anterior chamber changes during the combined surgery or staged surgery,which can provide a reliable and accurate basis for the operation planning.This study may bring benefit to the patient postoperative visual function.Objectives1.To retrospective investigate on the effect of the combined operation(PPV+Phaco+IOL implantation),and the staged operation(first-stage PPV,second-stage Phaco+IOL implantation)on the anterior segment parameters.2.To evaluate the effect of filling the vitreous cavity with silicone oil or filtered air on the anterior segment parameters of the eye during combined or staged surgery.3.To observe the effects of the two operation options(combined Phaco+PPV and PPV alone)on IOP,ACA and other anterior chamber parameters,and to explore the correlation between IOP and various of other parameters.Methods1.Retrospective analysis of the effects of the combined or staged surgery on the anterior segment.(1)We made a comparative analysis of the combined surgery(Phaco+IOL implantation+PPV)in 17 patients with 19 eyes,and staged surgery(PPV in Phase?,Phaco+IOL implantation in Phase?)20 patients with 20 eyes.Best-corrected visual acuity(BCVA),IOP,ACD and other related parameters were recorded preoperatively,1 week,1 month,3 months postoperatively.All patients were treated by the same experienced chief surgeon.The SPSS 19.0 statistical software was used to describe the trend of each index,to perform repeated measurement analysis and single factor analysis of postoperative changes in various indicators.(2)We compared the high-resolution anterior segment 3D analysis system(HR Pentacam)with partial coherence interferometry(IOL-Master)in measuring anterior chamber parameters.27 eyes of the anterior segment were measured with two instruments before operation,and the linear correlation of the measurement results was analyzed by Pearson linear correlation.2.Study the effect of filling vitreous body with silicone oil(SO)or filtered air on the parameters of anterior segment of the eye.According to the filling of SO or filtered air in the vitreous body,it was divided into SOT group(11 eyes)and FAT group(11 eyes).Among them,14 eyes received combined surgery(Phaco+IOL implantation+PPV)and 8 eyes received PPV surgery.HR Pentacam was used to measure the parameters of the anterior chamber before surgery,1 week,1 month and 3 months postoperatively.The BCVA and IOP at each time were also recorded,respectively.Statistical methods were used to analyze the effects of different tamponade of vitreous body on the anterior chamber parameters.3.To study the effect of cataract extraction on the anterior segment parameters and IOP in patients with PPV.A retrospective analysis of patients(31 eyes)with normal intraocular pressure(10-21mmHg)was divided into a combination group(PPV+Phaco+SOT)and a staged group(PPV+SOT).The changes of IOP,ACA and other anterior segment parameters were recorded before surgery,1 week after surgery,1 month after surgery and 3months after surgery.The postoperative changes of the main observation indexes were statistically analyzed.Regression analysis was performed on postoperative IOP and other anterior segment parameters.Results1.The postoperative ACD increased by 1.13±0.55mm and 0.92±0.67mm in the combined surgery group and the staged group,respectively,but no statistical significance was shown between the two groups,while K value and astigmatism postoperative changes also had no statistical significance.However,there was a statistically significant difference in postoperative changes between left and right eyes.The astigmatism of left eye is larger than right eye after surgery.The postoperative ACV and ACA were increased compared with preoperative,but has no significant difference between the two groups.The best visual acuity of Log MAR was better than that before operation,and no significant difference was noted between the two groups.The effect of age on visual acuity was statistically significant(P<0.05).The reduction of intraocular pressure after the combined surgery was 0.06±4.54 mmHg,and the staged group was 2.67±4.61 mmHg.There was no statistically significant difference between the two groups.The Pearson correlation coefficient of the ACD value is r=0.9,measured by the HR Pentacam system and the IOL-Master optical biometer(P<0.01),and the Pearson correlation coefficient of the K value is r=0.92(P<0.01).The correlation coefficients measured by the two methods are both greater than 0.9,indicating that the measurement consistency is good.When comparing the ACD measured by HR Pentacam with the IOL-Master,the former value should be added to the central corneal thickness(mean 525.7±34.7?m)for comparison.The difference between the two equipment was 0.03±0.15mm,and the difference was not statistically significant.The difference of K value was 0.06±0.19(t=0.5,P=0.62)and has no statistical significance.2.Among the patients who underwent the combined operation,the ACD of the SOT group and FAT group increased compared with preoperative groups,respectively.However,there was no significant difference between the two groups.ACV in the SOT group increased by 3.43±26.52mm~3 after 3 months,and the FAT group increased by37.00±19.85mm~3 after 3 months.The difference between the groups was statistically significant(P<0.05).Furthermore,there was no statistically significant change in corneal K value,astigmatism,and ACA in SOT group and FAT group after the operations.The visual acuity improved in both groups after the surgery,but there was no significant differences between the two groups.The IOP of the SOT group increased by 3.75±2.03mmHg in 3 months after the surgery,and the FAT group decreased by 1.93±1.90mmHg compared with the preoperative groups.The difference between the groups was statistically significant(P<0.05).The decreased ACD was present in patient who underwent PPV surgery in SOT group and an increased was shown in FAT group,but there was no significant difference between the two groups.There was no significant difference in ACV,corneal K value and astigmatism before and after surgery,and between the SOT group and FAT group.The decreased ACA in one week after the operation was statistically significant compared with the preoperative group.After 3 months,the SOT group was still lower than the preoperative group,and the FAT group was increased compared with the preoperative group.There was no statistical significance.The intraocular pressure of the SOT group increased by 3.35±2.11mmHg after the operation,and the intraocular pressure of the FAT group decreased by 0.58±0.64mmHg after the operation.There was no statistically significant difference between the groups.A comprehensive analysis of the variance analysis of the difference between different surgical methods and vitreous body substitutes can give the following conclusions.The effect of the SOT group and the FAT group on ACD was not statistically significant.The K value had a statistically significant change one week after the surgery.There was a statistically significant difference of ACV and astigmatism between the two groups.The change of ACA and IOP was not statistically significant between the two groups.3.The IOP of the combined group and the PPV group increased after surgery,and increased significantly at 1 week after operation.There was no significant difference between the two groups.The postoperative ACA changes in the combined group were2.23±6.82°,in the PPV group were-0.31±2.51°.There was no significant difference between the two groups.The ACV of the combined group gradually increased after operation,and the ACV of the PPV group decreased after operation.The difference between the two groups was statistically significant(P<0.05).The ACD of the combined group gradually increased after operation,and the ACD of the PPV group decreased after operation,the difference between them was statistically significant(P<0.05).There was no significant change in corneal K value between the two groups.Conclusions1.The ACD was higher in post operation eyes than that of pre-operation eyes.And the visual acuity was improved post both operation procedures(the combined surgery and the staged surgery).There was no significant difference between the two procedures in the ACD and visual function.2.The consistency of the HR Pentacam system and the IOL-Master optical biometer is good on ACD measurement.3.The vitreous cavity filled with disinfectant air has a greater influence on the anterior segment of the eye than the silicone oil tamponade.The gas filling group showed more significant increase in ACD and ACV,and decreased in IOP value.4.An increased IOP postoperatively was shown in both of the combined group(Phaco+PPV+SOT)and the PPV group(PPV+SOT),but the PPV group established more variable postoperative IOP.While the combined surgery can increase postoperative ACD,ACV and ACA,which caused IOP decreased by increaseing of ACD postoperatively.