Clinical Observation Of Retinal Displacement After Idiopathic Macular Hole Surgery

Objective:To observe the retinal displacement in macular area after par plana vitrectomy（PPV）combined with inner boundary membrane（ILM）peeling in patients with idiopathic macular hole（IMH）,and to explore the preoperative and intraoperative factors that may be related to the degree of displacement,and the correlation between the degree of displacement and postoperative visual acuity and retinal thickness.Methods:The clinical data of IMH patients who underwent PPV combined with ILM peeling in the Ophthalmology Center of our hospital in the past 3 years were retrospectively analyzed.The age,sex,eye type,best corrected vision acuity（BCVA）and optical coherence tomography（OCT）images were collected before and after operation.The same characteristic bifurcation of retina vascular point was selected from OCT images before operation and at 2 weeks（2w）,1 month（1m）and 2 months（2m）after operation,and the distance between it and the center of the macular area was measured to observe the displacement of the macular area before and after operation.The ratio of difference between MH-OD and F-OD to MH-OD,that is retinal displacement（%）,represents the degree of macular displacement to the optic disc.In addition,preoperative and postoperative parameters related to the microstructure of the macular area were obtained from the OCT images,and all the results were statistically analyzed to explore whether there was a correlation between each parameter and the degree of displacement.Results:1.A total of 41 eyes of 37 patients were included.The preoperative MH-optic disc distance（MH-OD）was（3940.00±355.16）μm.The macular fovea-optic disc distance（F-OD）at 2w,1m and 2m after surgery were（3820.32±335.93）μm,（3814.34±341.37）μm and（3799.68±338.55）μm,respectively.The postoperative F-OD values were lower than the preoperative MH-OD values.And the difference was statistically significant（F=41.342,P<0.001）.The preoperative distances from the center of the macular hole to the bifurcation of retinal vessels of the superior and inferior temporal arch（MH-SRV and MH-IRV）were（4115.07±651.44）μm and（3651.54±694.42）μm,respectively,which were greater than the postoperative F-SRV and F-IRV values.And the difference was statistically significant（χ2=27.894,P<0.001;F=9.371,P<0.001）.2.Correlation analysis of various diameter lines before operation and displacement degree of macular hole:there was no significant correlation between preoperative minimal diameter and postoperative retinal displacement（%）（all P>0.05）.There was a positive correlation between preoperative basal diameter and postoperative 2w displacement（%）(r_2w=0.332,P_2w=0.034),but no correlation between basal diameter and postoperative 1m,2m displacement（%）（all P>0.05）.There was no correlation between preoperative nasal and temporal arm length and postoperative displacement（%）（all P>0.05）.There was no significant correlation between preoperative nasal edge height and postoperative displacement（%）（all P>0.05）.There was a low positive correlation between preoperative temporal edge height and postoperative displacement（%）at 1m(r_1m=0.315,P_1m=0.045),but no correlation between preoperative temporal edge height and postoperative displacement（%）at 2w and 2m（all P>0.05）.3.Correlation analysis between preoperative macular hole area parameters,preoperative indicators and displacement degree:there was a moderate positive correlation between MHA,TA and the basal diameter of the MH(r _MHA=0.695;r _TA=0.546,all P<0.001).In addition,significant correlations between MHA,MHTA and the height of the nasal(r _MHA=0.589;r _TA=0.777,all P<0.001)and temporal edge of the hole(r _MHA=0.582;r _TA=0.775,all P<0.001).MHA and TA area were positively correlated with preoperative BCVA(r _MHA=0.538,P_MHA<0.001;r _TA=0.414,P_TA=0.007).In addition,there was no correlation between MHA and displacement（%）at 2w and 1m after surgery（all P>0.05）.MHA showed a low positive correlation with postoperative displacement（%）at 2m(r_2m=0.336,P_2m=0.032).There was a low positive correlation between TA and the displacement（%）at 1m and 2m after operation(r_1m=0.321,P_1m=0.041;r_2m=0.322,P_2m=0.040),but there was no correlation with the displacement（%）at 2 weeks after operation（P=0.106）.4.Influence of the type of vitreous cavity filling material on displacement degree:there was no statistical significance in central macular displacement（%）between vitreous cavity filling inert gas（C₃F₈）group and sterilized air group at each time point after surgery（P>0.05）.5.Correlation analysis between displacement degree and postoperative visual acuity:BCVA increased from（1.26±0.57）log MAR to（0.74±0.39）log MAR（χ2=48.279,P<0.001）,but there was no correlation between the displacement（%）and BCVA（all P>0.05）.6.Correlation analysis between displacement degree and retinal thickness:The retinal thickness in the nasal area of macula region was greater than that before surgery at each time point after surgery,and the difference was statistically significant（χ2=29.874;P<0.001）,the retinal thickness in the temporal region of macula was significantly thinner after operation,and the difference was statistically significant（χ2=52.467;P<0.001）.There was no correlation between the central displacement of macular（%）at 2w,1m and 2m after operation and the thickness of the retina of the nasal side（all P>0.05）,but there was a negative correlation between the central displacement（%）at 2w,1m and 2m after operation and the increase degree of temporal retinal thickness(r_2w=-0.475,P_2w=0.002;r_1m=-0.353,P_1m=0.024;r_1m=-0.377,P_1m=0.015).Conclusions:1.In the early stage（2 weeks）after PPV combined with ILM peeling in IMH eyes,the overall macular center would shift to the side of the optic disc.2.The basal diameter and the height of MH temporal edge was related to the postoperative macular location shift.The length of the nose and temporal arm,the length of the basal nasal and temporal segment,and the height of MH nasal were not correlated with the degree of displacement after operation.3.Preoperative MHA and TA area was positively correlated with preoperative basal diameter,nasal and temporal hole margin height,and preoperative BCVA.The size of MHA and TA was positively correlated with the degree of displacement after operation.4.Different vitreous cavity filling material have no effect on the degree of macular displacement.5.There was no correlation between the degree of postoperative macular center displacement and postoperative visual acuity.6.After IMH surgery,the retinal thickness on the nasal side of the macula increases and the temporal thickness becomes thinner.The degree of macular displacement is not related to the increase of nasal retinal thickness,but there is a negative correlation between the degree of macular displacement and the temporal retinal thickness,that is,the greater the degree of macular displacement,the thinner the temporal retinal thickness.