Correlation Between Fundus And Tongue Of Non-proliferative Diabetic Retinopathy Based On OCTA

ObjectiveIn this study,we examined and analyzed the blood flow and thickness change in the retina and choroid of NPDR patients based on the technique of optical coherence tomography angiography(OCTA)with non-proliferative diabetic retinopathy(NPDR)patients.Meantime,the characteristics of NPDR patients' tongue images were also added in the analysis process to evaluate the correlation between the fundus and tongue image changes of NPDR patients.This study ultimately explored whether the modern medical imaging technology could provide objective indicators for the extension of the visual inspection of traditional Chinese medicine,with the purpose of providing new ideas for the research of integrated Chinese and Western medicine methodology.MethodsThis study adopted a cross-sectional approach and collected 55 samples of NPDR patients who had been treated in our hospital from October 2019 to December 2019.All the candidate patients were examined using the mydriasis fundus examination,and the techniques of color fundus photography and fundus fluorescein angiography(FFA)to evaluate the stage of diabetic retinopathy(DR).Patients meeting the NPDR criteria were included in this study.If both eyes of the patient met the inclusion criteria,the patient's right eye was selected for study;if the patient's eyes were in different DR stages,the eye evaluated at a more severe stage was selected for study.All the patients were examined using the OCTA technique and the corresponding data was collected.This study used Angio Retina mode to scan an area of 3mm ×3mm with the macular fovea as the center.Through the software imbedded in the system,four levels of blood flow images were automatically generated:the superficial retinal capillary plexus(SCP),the deep retinal capillary plexus(DCP),the outer retina and the choroid capillary layer.The image with the highest scanning quality was used for analysis,and the Angiovue software was used to automatically calculate the blood flow density of SCP and DCP.At the same time,the system used its imbedded software to automatically identify and calculate the area of the foveal avascular zone(FAZ),the perimeter(PERIM),the acircularity index(AI),and the foveal blood flow density(FD)around the 300 ?m width of the foveal avascular zone.Then the Line mode was used to make a vertical line of the retinal pigment epithelium from the macular fovea and manually measure the central macular thickness(CMT)and the subfoveal choroidal thickness(SFCT).Then the GCC mode was used to record the total average loss of ganglion cell complex(GCC),the focal loss volume(FLV)and the global loss volume(GLV).At the same time,the patient's tongue image was collected with a camera under natural light,and was analyzed and recorded according to the "Traditional Chinese Medicine Tongue Color Atlas·New Century 2nd Edition",a national planning textbook designated in the "Eleventh Five-Year Plan".All the data were entered into an Excel sheet from the database and then analyzed statistically using SPSS 23.0.Data conforming to the normal distribution were tested using the independent sample t test;data not conforming to the normal distribution were tested using the non-parametric rank-sum test;test sensitivity and test specificity were analyzed by ROC curve.All tests were set to two-tailed tests,and P<0.05 was considered statistically significant.Results1.General information:all of the 55 patients in this study had type 2 non-proliferative diabetic retinopathy,among which 32 patients were male and 23 were female;age ranged from 40 to 77,with an average(58.15±9.036)years of age,and a medical history from two months to 20 years with an average of(13.10±5.85)years.2.OCTA results:?Changes in retinal blood flow:both the SCP(t=3.915,P<0.05)and DCP(t=3.479,P<0.05)levels of patients with severe NPDR were lower than those of patients with mild to moderate NPDR,and the difference was statistically significant.And SCP(AUC=0.776,P<0.05)held a higher test sensitivity and specificity to the different stages of DR than DCP(AUC=0.753,P<0.05).? Changes of the macular fovea without perfusion zone:the FD level(t=3.569,P<0.01)of patients with severe NPDR was lower than that of patients with mild to moderate NPDR,and the difference was statistically significant.No significant difference was observed in FAZ(Z=-0.348,P>0.05),PERIM(Z=-0.178,P>0.05),and AI(Z=-1.584,P>0.05).? Changes in retinal and choroid thickness:no significant difference in CMT(Z=-1.138,P>0.05)and SFCT(t= 0.408,P>005)was observed in patients with severe NPDR.?Changes of macular ganglion cell complex:the GCC thickness(Z=-2.006,P<0.05)in patients with severe NPDR increased compared with patients with mild to moderate NPDR,and the difference was statistically significant.No statistically significant differences in FLV(Z=-1.689,P>0.05)and GLV(Z=-0.322,P>0.05)were observed.3.Tongue image results:? Tongue color:the proportions of various tongue colors are:pale red tongue(43.64%),red tongue(30.91%),pale white tongue(14.55%),cyanosed tongue(9.09%),crimson tongue(1.82%).?Tongue shape:the proportions of enlarged and thin tongues are:enlarged tongue(52.73%),moderate tongue(43.64%),thin tongue(3.64%);the proportions of prickled tongues are:non-prickled(70.91%),prickled(29.09%);the proportions of ecchymosis tongue are:having no ecchymosis(94.55%)and having ecchymosis(5.45%);the proportions of tongue with tooth marks are:having tooth marks(52.73%)and having no tooth marks(47.27%);the proportions of tongue with crack are:having crack(67.27%)and having no crack(32.73%).? Tongue coating color:the proportions of various coating colors are yellow(63.64%)and white(36.36%).?Tongue coating condition:the proportions of thin and thick coating are:thin(78.18%),thick(21.82%);the proportions of moist and dry coating are:moist(65.45%),dry(32.73%),slippery(1.82%);the proportions of greasy coating are greasy(50.91%)and not greasy(49.09%).4.Analysis results of the correlation between the tongue image and the fundus:? The cases were divided into two groups according to the syndrome of whether there was exuberance of fire due to Yin deficiency indicated by the tongue images:32 cases which did not show exuberance of fire due to Yin deficiency(pale white tongue+pale red tongue)and 18 cases which showed exuberance of fire due to Yin deficiency(red tongue+crimson tongue).The results showed that:the two groups of SCP(t=0.438,P>0.05),DCP(t=0.456,P>0.05),FD(t=-1.074,P>0.05),SFCT(t=1.542,P>0.05),FAZ(Z=-0.445,P>0.05),PERIM(Z=-0.162,P>0.05),AI(Z=-0.010,P>0.05),CMT(Z=-0.222,P>0.05),GCC(Z=-0.526,P>0.05),and FLV(Z=-0.354,P>0.05),GLV(Z=-0.192,P>0.05)did not present statistically significant differences.?According to the severity of the retinal performance of NPDR patients,the characteristics of various tongue images were studied in groups:a.In terms of the tongue color,the proportion of pale white and red tongue(9.7%,0.0%)in patients with severe NPDR was smaller in comparison to patients with mild to moderate NPDR,and was smaller than that in group A(20.8%,4.2%),while the proportion of pale red tongue,cyanosed tongue and red tongue of patients with severe NPDR(45.2%,12.9%,32.3%)was higher than that of patients with mild to moderate NPDR(41.7%,4.2%,29.2%),suggesting that as the retinal performance of NPDR worsens,the symptoms of heating and blood stasis increase.b.In terms of the tongue shape,the proportion of thin tongue and fissured tongue in patients with severe NPDR(6.5%,74.2%)was higher than that in patients with mild to moderate NPDR(0%,58.3%),suggesting that as the disease progresses,patients with NPDR will have worse-level deficiency of both Qi and Yin,especially shown as aggravated Yin deficiency and insufficiency of essence and blood.c.In terms of tongue coating color,the proportion of yellow coating in patients with severe NPDR(64.5%)was higher than that of patients with mild to moderate NPDR(62.5%),also suggesting that as the diseases progresses,the symptoms of heating increase.d.In terms of the condition of the tongue coating,the proportion of dry coating and slippery coating in patients with severe NPDR(38.7%,3.2%)is higher than that in patients with mild to moderate NPDR(25.0%,0%),and in particular,the proportion of dry coating increased,which suggested that as the disease progresses,NPDR patients will have aggravated water production performance and metabolic disorder,especially insufficiency of body fluid caused by deficiency of water liquid formation.Conclusions1.With the progression of the NPDR disease,the retinal performance of patients with NPDR worsens,and the SCP,DCP,and FD levels decrease further in patients with severe NPDR than that in patients with mild to moderate NPDR while the GCC thickness increase.These can be used as non-invasive indicators for monitoring the progress of the DR disease.In addition,SCP shows more significant changes compared with DCP.2.The tongue image of patients with the NPDR disease at different stages show characteristics of pale red or red tongue,enlarged tongue,tongue having tooth marks and fissures,or thin,yellow and greasy tongue,which indicate symptoms and signs of deficiency of both Qi and Yin and internal accumulation of damp-heat.3.As the retinal performance of NPDR gets worse,the tongue image will change.Although it is not synchronized with the changes of retinal performance,it still reflects the trend of gradually aggravated symptoms of deficiency of both Qi and Yin,blood stasis,insufficiency of body fluid and dryness-fire.Therefore,the tongue image can provide indicators and theoretical basis for early clinical intervention in the treatment of NPDR.