Diabetic macular edema (DME) is one of the main causes of visual impairment in patients of working age. DME occurs in 4% of patients at all stages of diabetic retinopathy. Using a subthreshold micropulse laser is an alternative or adjuvant treatment of DME. Micropulse technology demonstrates a high safety profile by selectively targeting the retinal pigment epithelium. There are no standardized protocols for micropulse treatment, however, a 577 nm laser application over the entire macula using a 200 μm retinal spot, 200 ms pulse duration, 400 mW power, and 5% duty cycle is a cost-effective, noninvasive, and safe therapy in mild and moderate macular edemas with retinal thickness below 400 μm. Micropulse lasers, as an addition to the current gold-standard treatment for DME, i.e., anti-vascular endothelial growth factor (anti-VEGF), stabilize the anatomic and functional retinal parameters 3 months after the procedure and reduce the number of required injections per year. This paper discusses the published literature on the safety and application of subthreshold micropulse lasers in DME and compares them with intravitreal anti-VEGF or steroid therapies and conventional grid laser photocoagulation. Only English peer-reviewed articles reporting research within the years 2010–2022 were included.

Objectives: To evaluate the short- and long-term effects of subthreshold micropulse laser (SMPL) treatment on the microvascular network in diabetic macular edema (DME). Methods: This 12-month prospective study included 67 eyes (67 patients) with mild DME and good best-corrected visual acuity (BCVA), randomized into SMPL (33 eyes) or sham (34 eyes) groups. Assessments were performed at baseline (T1), 3 months (T2), and 12 months (T3). Optical coherence tomography (OCT) and OCT angiography (OCTA) were used to measure central retinal thickness (CRT), macular thickness (MT), macular volume (MV), foveal avascular zone (FAZ) area, microaneurysm (MA) count, and vessel parameters in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Results: The SMPL group showed a greater relative reduction in FAZ area in the SCP at 3 months (3.21 ± 13.03% vs. −5.73 ± 13.3%; p = 0.032) with a trend toward significance at 12 months (2.37 ± 12.47% vs. −3.3 ± 7.92%; p = 0.086) compared to the sham group. No changes in FAZ size, MA count, and other microvascular parameters were observed in either group. In the SMPL group, BCVA improved at 3 months (T2 > T1, p = 0.003); CRT decreased at 12 months (T2 > T3, p = 0.023); MT decreased at 12 months (T2 > T3, p = 0.006) and MV decreased at 12 months (T2 > T3, p = 0.007). No changes were detected in the sham group. No treatment-related complications occurred. Conclusions: SMPL may improve the macular microvasculature in mild DME by reducing FAZ size in the SCP. It provides visual and functional benefits while maintaining a favorable safety profile.

Numerous studies described a link between weather phenomena and an increased incidence of cardiovascular and cerebrovascular events. We report a case of ocular decompression retinopathy with massive premacular haemorrhage secondary to acute intraocular pressure reduction in a patient with acute primary angle closure. At the time of admission, a change in weather conditions occurred with high temperatures and a strong Foehn wind known locally as halny. A healthy 56-year-old man with acute primary angle closure who developed severe ocular decompression retinopathy with large prefoveal subhyaloid haemorrhage after pharmacological treatment was admitted to the hospital. The patient was elected for surgery and underwent vitrectomy with improvement of visual acuity to the baseline vision. This report suggests that, in addition to an abrupt reduction in intraocular pressure as a causative factor, massive ocular decompression retinopathy may be significantly influenced also by environmental factors such as halny.