The threshold micropulse laser is widely used in clinical practice as a safe, non-invasive laser for avariety of macular diseases. Compared with the conventional laser therapy, the subthreshold micropulse laser is selectively absorbed by the RPE and therefore it does not cause retinal damage. To explore the therapeutic mechanism and the safety, development of threshold micropulse laser in the treatment of various common macular diseases, and further clarify its indications and advantages, which are helpful for its wider clinical application.
ObjectiveTo analyze the expression of VEGF, IL-33 and NO concentration after laser photocoagulation and subthreshold micropulse laser photocoagulation conventional in proliferative diabetic retinopathy (PDR) patients.MethodsA case control study. The clinical data of 39 patients of PDR and 11 patients of idiopathic macular pucker (IMP) from Department of Ophthalmology, Central Theater General Hospital during November 2015 were collected in this study. PDR patients were assigned randomly into three groups. Fifteen PDR patients with 15 eyes were treated with conventional laser as group A. Thirteen PDR patients with 13 eyes were treated with subthreshold micropulse laser as group B. Eleven PDR patients with 11 eyes without any laser therapy were grouped as C. Eleven IMP patients were grouped as D. There was no difference of age (F=0.53, P=0.23), gender ratio (χ2=0.55, P=0.91), body mass index (F=2.62, P=0.07), duration diabetes (F=0.29, P=0.75), glycoslated hemglobin (F=1.72, P=0.19) in four groups. All PDR patients were examined with FFA. Total protein was quantified by a bicinchoninic acid assay kit. Levels of VEGF, IL-33, NO were determined using enzyme-linked immunosorbent assay kits.ResultsThere was no difference of total protein in four groups (F=1.78, P=0.17). Group C had a higher VEGF level than group A and B (F=7.84, P=0.002). Group A had a higher IL-33 level than group C (t=4.15, P=0.02). There was no difference of IL-33 level in group B and C (t=1.34, P=0.20). Group D had a lower NO level than group A, B, C (F=38.42, P＜0.001). There was no difference of NO level in group A, B and C (F=3.29, P=0.06).ConclusionsBoth conventional laser photocoagulation and subthreshold micropulse laser photocoagulation can decrease vitreous VEGF level and subthreshold micropulse laser photocoagulation can induce less IL-33 level.