Correlation of visual acuity and central macular morphology in different types of diabetic macular edema

AIM:To observe the correlation of visual acuity and central macular morphology in patients with different types of diabetic macular edema(DME). <p>METHODS: Presented study was single-center, uncontrolled retrospective clinical study. Sixty-two patients(103 eyes)with DME were included. Best corrected visual acuity(BCVA)was evaluated using early treatment diabetic retinopathy study(ETDRS)vision test chart. All patients were examined by non-contact tonometer, slit lamp, indirect ophthalmoscope, and fundus fluorescein angiography(FFA). Central subfield mean thickness(CSMT)in the macular area of diameter 1mm was measured by optical coherence tomography(OCT).And in the same time the integrity of inner segments/ outer segments(IS/OS)and external limiting membrane(ELM)reflecting light strip of 350μm center horizontal scanning line was investigated by OCT. BCVA and CSMT in different types of DME patients were analyzed using Kruskal- Wallis test. BCVA and CSMT between the two-two groups in different types of DME patients were analyzed using Nemenyi test, and multiple regression analysis was used to analyze the relative factors of BCVA. <p>RESULTS: In the 103 eyes, 47 eyes(45.6%)were focal DME, 35 eyes(34.0%)were diffuse DME, 6 eyes(5.8%)were ischemic DME and 15 eyes(14.6%)were proliferative DME. The difference of mean BCVA(<i>H</i>=69.167, <i>P</i><0.01)and mean CSMT(<i>H=</i>57.113, <i>P</i><0.01)in different types of DME patients was statistically significant. Comparison of BCVA and CSMT between the two-two groups showed statistically significant difference in focal DME and diffuse DME(BCVA:<i>χ</i>²=14.982,<i>P</i><0.01; CSMT:<i>χ</i>²=14.537,<i>P</i><0.01), focal DME and ischemic DME(BCVA:<i>χ</i>²=15.596,<i>P</i><0.01; CSMT:<i>χ</i>²=15.393,<i>P</i><0.01), focal DME and proliferative DME(BCVA:<i>χ</i>²=16.567,<i>P</i><0.01; CSMT:<i>χ</i>²=15.687,<i>P</i><0.01), diffuse DME and ischemic DME(BCVA:<i>χ</i>²=12.974、<i>P</i>=0.008; CSMT:<i>χ</i>²=13.999,<i>P</i><0.01). By multiple lineal regression analysis, CSMT, the integrity of IS/OS and ELM reflecting light strip of 350μm center horizontal scanning line, the course of disease and the type of DME correlated to BCVA(<i>r</i>=-0.064,-0.207,-0.082 and -0.160, respectively, <i>P</i><0.05). The glycosylated hemoglobin, intraocular pressure, age and sex were not associated to BCVA(<i>r</i>=-0.885, -2.522, -1.504, and-0.595, respectively, <i></i>P<i>></i>0.05). <p>CONCLUSION: There are statistically significant differences on macular morphology and vision function among different types of DME patients