| Objective:Appplication of optical coherence tomography depth enha ncement imaging(EDI-OCT)to scan macular region choroid of high my opia,and mearsure choroidal thickness.To study choroidal thickness variat ion and differences in macular region of normal,low and high myopic p atients.To discuss the effect of axial length,corneal curvature and refracti ve error on choroidal thickness in macular region of patients with highmyopia.Method:Controlled clinical studies.From August 2014 to August 2015,select 66 eyes of 34 subjects with high myopia(spherical equivalent r efractive error greater or equal to-6 diopters or axial length gearter or equal to 26 ㎜)who were referred to our High Myopia Clinic at The Fourth Hebei Medcal University Hospital,and chose 75 eyes of 39 healt hy volunteers as a clinical control group.Using Cirrus HD-OCT enhance d depth imaging technology,The scanning the macular region 6mm thr ough the fovea scan lines,0°and 90°azimuth.Measurement of foval choro idal thickness and by foveal choroidal thickness in nasal and temporal i nterval of 500μm until 2500μm.Using Lenstar 900 non-contact biologica l gauge to check the axail length,horizontal corneal curvature and vertic al corneal curvature,and test three times,and the datas were read by an alysis software.Using SPSS 22.0 statistical software to process data,the s ignificance level of normality test and homogeneity of variance test was0.1,other various statistical analyzes were P>0.05 was considered statis tically significant.Result:1 Baseline clinical characteristics:two groups in age,gender distribu tion and the distribution of the eyes was no dignificant difference.2 The result of intraocular pressure,refraction error,axial length and corneal curvature in two groups.2.1 High myopia group: the mean(±standard deviation)baseline intr aocular pressure was 14.58±2.23 mmHg,mean refraction error-8.07±1.95 diopters,mean axial length 26.49±1.19 ㎜,mean horizontal corneal curvatu re 43.24±1.56 diopters,and mean vertical corneal curvature 44.57±1.64 d iopters.2.2 Clinical control group:the mean(±standard deviation)baseline in traocular pressure was 14.84±2.26 mmHg,mean refraction error-1.32±1.16 diopters,mean axial length 23.77±0.87 ㎜,mean horizontal corneal curv ature 43.31±1.35 diopters,and mean vertical corneal curvature 44.15±1.38 diopters.2.3 Between the two groups,there was a significant difference in re fraction error and axial length(P<0.05);but there was no difference in in traocular pressure,horizontal corneal curvature and vertical corneal curvat ure(P>0.05).3 Choroidal thickness measurement(unit:μm): 3.1 High myopia group:the mean choroidal thickness of every positions(±standard deviation),subfoveal(186.86±53.713),nasal 500(173.92±56.71),n asal1000(164.44±56.09),nasal 1500(149.61±54.78),nasal 2000(131.68±52.56),nasal 2500(114.91±45.76);temporal side to fovea 500(186.53±51.16),te mporal 1000(193.35±54.53),temporal 1500(198.11±54.52),temporal 2000(192.26±54.02),temporal 2500(182.23±56.10).Choroid was the thickest in t he temporal 1500(213),followed by subfovea(202),and the thinnest in thenasal 2500(133).Compared with the symmetrical position of choroida l thickness,temporal choroidal thickness was greater than the nasal side,t he difference was statistically significant(P<0.05).3.2 Clinical control group:subfovea(274.08±63.62),nasal side to fov ea 500(259.38±61.62),nasal 1000(246.93±64.52),nasal 1500(228.04±64.51),nasal 2000(208.76±63.38),nasal 2500(179.14±56.57),and temporal side to fovea 500(260.97±55.97),temporal 1000(259.15±54.39),temporal 1500(251.26±52.71),temporal 2000(239.54±55.85),temporal 2500(218.45±53.69).Ch oroid was the thickest in the subfovea(288),followed by temporal 2500(232),the thinnest side was nasal 2500(198).Compared with the symmetri cal position of the choroidal thickness,nasal 500 was greater than tempo ral 500,but the other position,temporal choroidal thickness was greater t han nasal side,the difference was statistically significant(P<0.05).3.3 Choroidal thickness variation:Choroidal thickness of the high myopia group respectively compare d to the clinical control group,overall test positions were smaller,and t he difference was significant(P≤0.001).Subfovea choroidal thickness var iation of high myopia was greatest,followed by nasal,the smallest cha nge in temporal choroid,the difference was statistically significant(P<0.001).4 Analysis of the correlation between choroidal thickness and age,g ender,eye,intraocular pressure,corneal curvature and refraction error in tw o groups(unit:μm):4.1 Choroidal thickness of respectively positions were no correlatio n with age,gender,eye,intraocular pressure and corneal curvature(P>0.05)in two groups.4.2 High myopia group:choroidal thickness of temporal side to fo vea 1500,temporal 2000 and temporal 2500 were no correlation with ref raction error(P>0.05);but choroidal thickness had positive correlation wi th refraction error at subfovea,temporal 500,temporal 1000,nasal 500,nasa l 1000,nasal 1500,nasal 2000 and nasal 2500(P<0.001).4.3 Clinical control group:choroidal thickness was positive correlat ion with refraction error at subfovea,temporal 500,nasal 500,nasal 1000,n asal 1500,nasal 2000,nasal 2500(P<0.05);but there was no correlation be tween choroidal thickness and refraction error at temporal 1500,temporal2000 and temporal 2500(P>0.05).5 Analysis of the correlation between axial length and age,gender,eye,intraocular pressure,corneal curvature and refraction error in two groups:5.1 High myopia group:there was no correlation between axial len gth and distribution of the eye,age(P>0.05),and axial length had posi tive correlation with intraocular pressure(P<0.05),but there was a wea k correlation with them;axial length had negative correlation with refract ion error,horizontal corneal curvature,vertical corneal curvature,distribut ion of the gender(P<0.001).5.2 Clinical control group:there was no correlation between axial l ength and age,distribution of the eye,gender,intraocular pressure,refra ction error(P>0.05).Axial length had negative correlation with horizont al corneal curvature,vertical corneal curvature(P<0.05).6 Analysis of the correlation between axial length and choroidal thickness in two group(unit:μm):6.1 High myopia group: choroidal thickness in temporal side to fo vea 2000,temporal 2500 were no correlation with axial length(P>0.05),and choroidal thickness in subfovea,temporal 500,temporal 1000,tem poral 1500,nasal side to fovea 500,nasal 1000,nasal 1500,nasal 2000,nasal 2500 had negative correlation with axial length(P<0.001).6.2 Clinical control group: choroidal thickness in nasal side to fove a 1500 had negative correlation with axial length(P<0.05),and choroid al thickness in nasal side to fovea 500,nasal 1000,nasal 2000,nasal 2500,subfovea,temporal side to fovea 500,temporal 1000,temporal 500,temporal 1000,temporal 1500,temporal 2000 and temporal 2500,they all had no correlation with axial length(P>0.05).Conclusion:1 The choroidal thickness of fovea was the thickest in the macular region,and gradually thinning to temporal and nasal side in normal gr oup,and the temporal side was greater than nasal side;otherwise,the choroidal thickness of temporal side was the thickest in the macular reg ion in high myopia group,and the subfovea was thicker than nasal sid e.2 Choroidal thickness in high myopia group was thinner than norm al group at all places;and the variation of subfovea was greatest,and nasal side was greater than temporal side.3 Choroidal thickness in macular region gradually became thinner with the increase of refraction error.4 Choroidal thickness in macular region became gradually thinner when axial length became longer. |
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