The Research About Changes Of Pupil And Choroidal Thickness In Patients With Type 2 Diabetes Mellitus

Objective:To investigate the effect of diabetic autonomic neuropathy on the ocular tissue(pupil and choroidal blood flow)by comparing the differences of pupil changes and choroidal blood flow in patients with diabetic retinopathy and normal control.Methods:Thirty patients(60 eyes)with type 2 diabetes mellitus(diabetic retinopathy 0-2)and twenty-one normal volunteers(42 eyes)were enrolled using the pupillarymetry and the Heidelberg frequency domain OCT.Subfoveal choroidal thickness(SFCT)is manually measured using the instrumental caliper of the Heidelberg frequency domain OCT,which is the distance from the outer edge of the high-reflection signal layer representing the retinal pigment epithelium to the inner surface of the sclera.All examinations were performed by the same ophthalmologist,and the results were tested for repeatability.In order to avoid selective bias,Choroidal thickness was assessed using a spectral-domain optical coherence tomography and enhanced depth mode at 13 locations(subfoveal and 1 measurements 500 mm apart in 4 directions—nasal,temporal,superior,and inferior).The pupil function was measured using the ocular refraction center integrated pupil measurement,and the same ophthalmologist was operated and the results were tested for repeatability.The pupil diameter of the different intensity illumination stimulation(0cd/?,1 cd/?,10 cd/?,100 cd/?)was measured,and the pupil contraction rate after light stimulation,the pupil contraction amplitude after light stimulation,and so on.Data were analyzed by SPSS 22.0software for statistical analysis.Result:1.the general informationThe mean age of patients with type 2 diabetes mellitus was 50±9.5years old,and the average age of the control group was 48.4±10.6 years old.There was no significant difference between the two groups(P>0.05).There was no significant difference in the choroidal thickness between the left and right eyes of the type 2 diabetes mellitus group and the normal control group compared with the pupil diameter.The mean duration of type2 diabetes was 4.26 years,and the fundus DR stage was 0 or only mild aneurysm changed.The mean fractional visual acuity was 0.87±0.23 in the type 2 diabetes group and 1.06±0.11 in the control group,and the difference was statistically significant(P<0.05).All data were consistent with normal grouping,compared with independent sample T test.2.the results of pupil measurementType pupil diameter measured under intensity of light in the type 2diabetes mellitus,pupil diameter measured after intensity irradiation at 10cd/m~2,pupil diameter measured after light intensity illumination,pupil diameter measured after 100 cd/m~2 intensity illumination,light stimulation.The rate of pupil contraction was 4.65±0.75 mm,2.91±0.60mm,2.27±0.40 mm,1.99±0.30 mm,4.86±0.96 mm/s,1.45±0.31 mm,respectively.The diameter of the pupil under the darkroom of the control group,the pupil diameter measured after 1 cd/m~2 intensity illumination in the control group,the pupil diameter measured after 10 cd/m~2 intensity illumination,the pupil diameter measured after 100 cd/m~2 intensity illumination,The rate of contraction was 5.24±0.70 mm,2.21±0.70 mm,2.53±0.48 mm,2.15±0.34 mm,5.10±0.66 mm/s,1.57±0.30 mm,respectively.There was significant difference between the darkroom pupil diameter and the pupil contraction amplitude(P<0.05).Among them,the darkroom pupil diameter and pupil contraction amplitude and pupil contraction rate was positively correlated.3.the results of choroid thicknessThe choroid thickness of subfoveal and 1 measurements 500 mm apart in 4 directions—nasal,temporal,superior,and inferior,choroidal thickness of macular fovea is the thickest.The thickness of the choroid and the mean value of the five points in the type 2 diabetes group were thinner than those in the control group,the difference was statistically significant.(P<0.01)4.the results of diabetes subgroup analysisIn the control group,the size of pupil diameter was used as a reference.The type 2 diabetes mellitus was divided into two groups:pupil diameter group and small group.Among them,there were 17 eyes with large pupil diameter and 33 eyes in the pupil diameter group.The age of the two groups matched the results.Showing that the pupil diameter group was thinner than the pupil diameter group.Conclusion:(1)Diabetic patients have no obvious visual impairment before pupil diameter,pupil contraction amplitude and pupil shrinkage rate of the smaller and thinning of the choroid thickness;(2)diabetic patients,the pupil smaller also exist Thinning of choroid thickness;(3)diabetic patients with small pupil and thinning of choroid thickness may be due to autonomic nerve damage caused.