The Study Of Krypton Laser Photocoagulation For Diabetic Macular Edema

With the development of living standard, diabetes has become one of the diseases harm to people's health severely, and the third leading chronic disease after tumors and cardiovascular disease. Diabetic retinopathy (DR) is one of the most serious complications of diabetes, also a main disease leading to blindness in western country. The incidence rate of DR is closely related to the incidence of diabetes in crowd and course. Diabetic macular edema (DME) is main cause leading to decreased visual acuity in DR. In terms of various course and type of DR, the incidence rate of DME is 3%~70%.Laser photocoagulation has been proved to be the most effective and safest measure in the treatment of DR, which can reduce the blindness rate by 90% or more, through improving the regression and disappearance of new vessels. The Early Treatment Diabetic Retinopathy Study has summarized the efficacy of laser photocoagulation of patients with clinically significant diabetic macular edema (CSME). Patients with preproliferative or proliferative diabetic retinopathy (PDR) need pan-retinal photocoagulation and focal macular photocoagulation. Although many researches has been done to the subsequence of this two kinds of photocoagulations, detailed quantitative study has not been done to efficacy of focal photocoagulation combined with pan-retinal photocoagulation for diabetic macular edema from alteration in retinal function and retinal morphosis.It is proved that DME is leading cause to decrease in vision, and different types of diabetic maculopathy are related to visual prognosis. Short-term visual prognosis after retinal laser photocoagulation for DME has suggested to be closed related to the distance of retinopathy lesions from macular fovea in some studjes. However, the study has not been done to explore to influential factors of vision prognosis after laser photocoagulation in multiple factors analysis from fluorescein angiography.Part 1. Krypton laser combined macular grid and pan-retinal photocoagulation for diabetic macular edemaObjective To explore the efficacy of combined macular grid and pan-retinal laser photocoagulation for CSME through quantitatively studying the changes of macular retina thickness, retinal function and leaks in macular area with optical coherent tomography (OCT), multifocal electroretinopathy (MERG), and fluorescein angiography (FFA).Methods 38 patients (76 eyes) with preproliferative or PDR with diffuse macular edema which conform to inclusion criteria were included and randomly assigned into two groups. Group A is macular grid combined with pan-retinal photocoagulation, and group B is pan-retinal photocoagulation. The contrast analysis of pre-operative and post-operative visual acuity, macular retinal thickness and macular retinal function were prospectively evaluated with OCT, MERG and FFA.Results The improvement of visual acuity was found to be better in- group A than in-group B after laser photocoagulation. Three months after photocoagulation, the improvement and stable in visual acuity is 33 eyes in group A, 14eyes in group B. Compared with preoperative level, the macular fovea retinal thickness decreased in group A, but increased in group B (P<0.05). The differences of changes of macular leakages in two groups were significant, no leakages in group A was 17 eyes, 3 eyes in group B. Compared with preoperative level, the implicit times of N1, P1 wave were delayed and amplitudes of all wave were decreased in macular 00,50,100 area and average retina. However, in macular area, the delay of implicit times of P1 wave and the decrease of amplitudes of N1, P1 wave in-group B was more than in-group A.Conclusions The efficacy of macular grid photocoagulation combined with pan-retinal photocoagulation is better than pan-retinal photocoagulation in the treatment of preproliferative and proliferative with diffuse macular edema.