Passos Renato M, Malerbi Fernando K, Rocha Marindia, Maia Maurício, Farah Michel E
Federal University of Sao Paulo (UNIFESP/EPM), Sao Paulo, SP, Brazil.
Instituto da Visão (IPEPO), Rua Borges Lagoa 1083, São Paulo, SP, 04038-032, Brazil.
Int J Retina Vitreous. 2021 Jan 9;7(1):4. doi: 10.1186/s40942-020-00268-3.
Diabetic macular edema (DME) is a major cause of visual impairment and its treatment is a public health challenge. Even though anti-angiogenic drugs are the gold-standard treatment, they are not ideal and subthreshold laser (SL) remains a viable and promising therapy in selected cases. The aim of this study was to evaluate its efficacy in a real-life setting.
Retrospective case series of 56 eyes of 36 patients with center-involving DME treated with SL monotherapy. Treatment was performed in a single session with the EasyRet® photocoagulator with the following parameters: 5% duty cycle, 200-ms pulse duration, 160-µm spot size and 50% power of the barely visible threshold. A high-density pattern was then applied to the whole edematous area, using multispot mode. Best corrected visual acuity (BCVA) and optical coherence tomography (OCT) data were obtained at baseline and around 3 months after treatment.
Fifty-six eyes of 36 patients were included (39% women, mean age 64.8 years old); mean time between treatment day and follow-up visit was 14 ± 6 weeks. BCVA (Snellen converted to logMAR) was 0.59 ± 0.32 and 0.43 ± 0.25 at baseline and follow-up, respectively (p = 0.002). Thirty-two percent had prior panretinal photocoagulation (p = 0.011). Mean laser power was 555 ± 150 mW and number of spots was 1,109 ± 580. Intraretinal and subretinal fluid (SRF) was seen in 96 and 41% of eyes at baseline and improved in 35 and 74% of those after treatment, respectively. Quantitative analysis of central macular thickness (CMT) change was performed in a subset of 23 eyes, 43% of which exhibited > 10% CMT reduction post-treatment.
Subthreshold laser therapy is known to have RPE function as its main target, modulating the activation of heat-shock proteins and normalizing cytokine expression. In the present study, the DME cases associated with SRF had the best anatomical response, while intraretinal edema responded poorly to laser monotherapy. BCVA and macular thickness exhibited a mild response, suggesting the need for combined treatment in most patients. Given the effect on SRF reabsorption, subthreshold laser therapy could be a viable treatment option in selected cases.
糖尿病性黄斑水肿（DME）是视力损害的主要原因，其治疗是一项公共卫生挑战。尽管抗血管生成药物是金标准治疗方法，但它们并不理想，而阈下激光（SL）在某些情况下仍然是一种可行且有前景的治疗方法。本研究的目的是评估其在实际临床中的疗效。
对36例累及黄斑中心凹的DME患者的56只眼进行回顾性病例系列研究，采用SL单一疗法治疗。使用EasyRet®光凝器在单次治疗中进行治疗，参数如下：占空比5%，脉冲持续时间200毫秒，光斑大小160微米，功率为刚刚可见阈值的50%。然后使用多点模式将高密度图案应用于整个水肿区域。在基线和治疗后约3个月时获取最佳矫正视力（BCVA）和光学相干断层扫描（OCT）数据。
纳入36例患者的56只眼（女性占39%；平均年龄64.8岁）；治疗日至随访的平均时间为14±6周。基线时和随访时的BCVA（Snellen视力换算为logMAR）分别为0.59±0.32和0.43±0.25（p = 0.002）。32%的患者曾接受过全视网膜光凝治疗（p = 0.011）。平均激光功率为555±150毫瓦，光斑数量为1,109±580。基线时，96%和41% 的眼中可见视网膜内液和视网膜下液（SRF），治疗后这些眼中分别有35%和74%得到改善。对23只眼的亚组进行了黄斑中心厚度（CMT）变化的定量分析，其中43% 的眼在治疗后CMT降低超过10%。
已知阈下激光疗法以视网膜色素上皮（RPE）功能为主要靶点，可以调节热休克蛋白的激活并使细胞因子表达正常化；在本研究中与SRF相关DME病例在解剖学上的反应最佳，而视网膜内水肿对激光单一疗法反应不佳。BCVA和黄斑厚度显示出轻度反应，这表明大多数患者需要联合治疗。鉴于对SRF重吸收有作用，阈下激光疗法在某些选定病例中可能是一种可行的治疗选择。
