Subthreshold micropulse diode laser treatment in diabetic macular edema: biological impact, therapeutic effects, and safety.

PURPOSE: To introduce the treatment of diabetic macular edema (DME) with subthreshold micropulse diode laser (SMPL), to summarize the biological impact, therapeutic effects, and safety of this treatment, and to discuss the response to DME when SMPL is combined with anti-vascular endothelial growth factor (anti-VEGF) or steroid. METHODS: The literature search was performed on the PubMed database, with a selection of English-language articles published from 2000 to 2023 with the following combinations of search terms: diabetes macular (o) edema, micropulse laser or subthreshold micropulse laser, anti-vascular endothelial growth factor, and steroid. RESULTS: SMPL is a popular, invisible retinal laser phototherapy that is inexpensive, safe, and effective in the treatment of DME. It can selectively target the retinal pigment epithelium, reduce the expression of pro-inflammatory factors, promote the absorption of macular edema, and exert a similar and lasting clinical effect to traditional lasers. No significant difference was found in the therapeutic effects of SMPL between different wavelengths. However, HbA1c level and pretreatment central macular thickness (CMT) may affect the therapeutic outcomes of SMPL. CONCLUSION: SMPL has a slow onset and produces lasting clinical effects similar to conventional photocoagulation. It has been reported that SMPL combined with the intravitreal anti-VEGF injection can significantly reduce the number of injections without influencing the therapeutic effect, which is essential for clinical applications and research. Although 577 nm SMPL is widely used clinically, there are no standardized protocols for SMPL. Additionally, some important problems regarding the treatment of SMPL require further discussion and exploration.

Analysis of the Macular Region Following Panretinal Photocoagulation for the Treatment of Diabetic Retinopathy Using Optical Coherence Tomography.

Background: Diabetic retinopathy (DR) is the most prevalent microvascular complication of diabetes. Panretinal photocoagulation (PRP) is the established treatment for mitigating severe visual impairment resulting from proliferative DR. Objective: This study aims to investigate the impact of PRP on the macular region in patients with DR, utilizing optical coherence tomography (OCT) for assessment. Design: An experimental study was meticulously designed, implementing PRP as the primary intervention. Setting: The investigation was conducted within the Department of Ophthalmology at the Affiliated Huaian No.1 People's Hospital, Huai'an, Jiangsu, China. Participants: A total of 120 participants diagnosed with DR and undergoing treatment at our hospital were enrolled in the study. Interventions: The participants were randomly assigned to either the control group (CG, n = 60) or the study group (SG, n = 60). The CG received conventional drug treatment involving oral iodized lecithin, while the SG received PRP. OCT was employed to monitor changes in macular fovea volume and macular retinal thickness. Primary Outcome Measures: Evaluation criteria encompassed clinical efficacy, macular fovea volume, macular retinal thickness, IL-6 and VEGF levels, incidence of adverse reactions, and quality of life in both groups. Results: The study resulted in a higher total effective rate in the SG (96.67%) compared to the CG (80.00%) (χ2 = 8.09, P < .05). Post-treatment, reductions were observed in macular fovea volume and macular retinal thickness, with significantly lower SG values than CG values (P < .05). Both serum IL-6 and VEGF levels exhibited reductions in both groups after treatment, with the SG displaying a more significant decrease compared to the CG (P < .05). The occurrence of adverse reactions significantly decreased in the SG relative to the CG (P < .05). Quality of life scores for the SG was notably elevated compared to the CG (P < .05). Conclusions: PRP emerges as a highly valuable approach in the management of DR. It contributes to retinal thickness improvement within the macular region and inflammation reduction, and also enhances therapeutic outcomes, minimizes adverse reactions, and optimizes patients' quality of life. These findings warrant further clinical adoption and widespread promotion.

Therapeutic Efficacy of Intravitreal Conbercept Injections with or without Focal Macular Photocoagulation for Diabetic Macular Edema.

Objective: This study aimed to investigate the effectiveness and safety of intravitreal conbercept injections with or without focal macular photocoagulation in the treatment of diabetic macular edema (DME). Methods: This retrospective study included 60 DME patients (60 eyes) divided into two treatment groups. The conbercept group received monthly intravitreal injections for 5 consecutive sessions, while the combination therapy group received intravitreal injections and focal macular photocoagulation. Changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) were observed before and at months 1, 3, 6, 9, and 12 after treatment in both groups, along with the number of intravitreal conbercept injections administered. Results: At 1, 3, 6, 9, and 12 months after treatment, both the conbercept and combined treatment groups showed improvement in best-corrected visual acuity (BCVA) and decrease in central macular thickness (CMT) compared to before treatment, with statistical significant differences (P < .05). However, the differences in BCVA and CMT between the two groups at each time point after treatment were not significant (P > .05). During the 1-year follow-up period, the mean number of injections in the combined treatment group was 6.3±0.8, which was less than that in the conbercept treatment group (7.6 ± 0.9), with a significant difference (t = 5.556, P < .001). The incidence of subconjunctival hemorrhage was 10.9% and 10.5% in the two groups, respectively, with no significant inter-group difference (χ² = 0.013, P = .908). None of the patients exhibited serious treatment-related ocular and systemic complications during the treatment period. Conclusions: Treatment of DME with intravitreal conbercept injections, whether with or without focal macular photocoagulation, is safe and effective in improving the patients' visual acuity and retinal anatomy. However, patients who receive combined treatment require fewer intravitreal injections than those who receive conbercept treatment alone.

Retina rejuvenation therapy for diabetic macular edema: a pilot study.

PURPOSE: To prospectively investigate the safety and efficacy of a novel frequency-doubled nanosecond-pulsed laser with discontinuous beam energy distribution (2RT, Ellex) for the treatment of diabetic macular edema. METHODS: Twenty-three consecutive patients (38 eyes) with newly diagnosed diabetic macular edema were recruited and assessed with logarithm of the minimum angle of resolution best-corrected visual acuity, central macular thickness measured with optical coherence tomography (OCT/scanning laser ophthalmoscope, OPKO/OTI), microperimetry, fundus photography, and fundus fluorescein angiography. Macular grid treatments were performed with 2RT laser system by 1 operator. Patients were examined with logarithm of the minimum angle of resolution best-corrected visual acuity, central macular thickness, microperimetry, and fundus photography at 3 weeks and 6 weeks and 3 months and 6 months. Fundus fluorescein angiography was repeated at 3 months and 6 months. RESULTS: Six months postoperatively, 17 patients (28 eyes) completed the study. No complications were identified after 2RT therapy. Intraoperative retinal discoloration was observed in 2 cases, fully resolved at 3 months with no permanent anatomical or functional changes. Mean logarithm of the minimum angle of resolution visual acuity improved from 20/44 at baseline to 20/27 at 6 months. The change in best-corrected visual acuity was significant (P = 0.0190). Central macular thickness in the central 1-mm subfield, retinal exudates and vascular leakage decreased in the majority of patients at 6 months (46, 41, and 55%, respectively), although the change from baseline was not statistically significant. Microperimetry confirmed photoreceptor integrity and showed a trend of improvement that correlated with decreased central macular thickness. CONCLUSION: For the first time, we achieved a beneficial effect on diabetic macular edema without the side effects of conventional laser therapy. The efficacy of this system in comparison with standard argon laser photocoagulation and in the treatment of other conditions affecting the retinal pigment epithelium needs further investigation.

Subthreshold diode micropulse laser photocoagulation (SDM) as invisible retinal phototherapy for diabetic macular edema: a review.

PURPOSE: To present the state-of-the-art of subthreshold diode laser micropulse photocoagulation (SDM) as invisible retinal phototherapy for diabetic macular edema (DME). METHOD: To review the role and evolution of retinal laser treatment for DME. RESULTS: Thermal laser retinal photocoagulation has been the cornerstone of treatment for diabetic macular edema for over four decades. Throughout, laser induced retinal damage produced by conventional photocoagulation has been universally accepted as necessary to produce a therapeutic benefit, despite the inherent risks, adverse effects and limitations of thermally destructive treatment. Recently, SDM, performed as invisible retinal phototherapy for DME, has been found to be effective in the absence of any retinal damage or adverse effect, fundamentally altering our understanding of laser treatment for retinal disease. SUMMARY: The discovery of clinically effective and harmless SDM treatment for DME offers exciting new information that will improve our understanding of laser treatment for retinal disease, expand treatment indications, and improve patient outcomes.

Subjective visual sensation during vitrectomy under retrobulbar anesthesia.

PURPOSE: To report a precise illustrated image of patient's view during vitrectomy. DESIGN: Interventional case report. METHODS: A 56-year-old male with cystoid macular edema (CME) associated with epiretinal membrane underwent vitrectomy. The patient seemed to find gratification in being operated on because he was able to see what was going on. He was a professional artist in computer graphics, and he drew three different pictures depending on the surgical procedures. RESULTS: These pictures depicted the moving of pasty, whirling fluid during core vitrectomy, numerous black or gray spots like snowflakes by intravitrealy injected crystals of triamcinolone acetonide, and a sharp tapered instrument coming into the center and membrane-like material being peeled off. CONCLUSIONS: Patients may see a precise shape in a constant size, scale, and detailed movement as well, focused on the retina without described optics. Further investigation will be required to determine this mechanism.

Intravitreal triamcinolone acetonide as an adjuvant therapy to panretinal photocoagulation for proliferative retinopathy with high risk characteristics in type 1 diabetes: case report with 22 weeks follow-up.

PURPOSE: To describe a new treatment protocol to deliver panretinal photocoagulation that may avoid further deterioration of vision in patients with type 1 diabetes mellitus with proliferative retinopathy with high risk characteristics for severe visual loss and cystoid macular oedema. METHODS: Fundus photography, measurement of foveal thickness with optical coherence tomography and best corrected visual acuity (BCVA) determined by Snellen and ETDRS charts were measured before and after treatment in a 28-year-old man. RESULTS: Over 9 weeks, BCVA improved from 0.05 to 0.25 and the number of letters read at 2 metres from four to 39 after panretinal photocoagulation and adjuvant intravitreal triamcinolone injection under intraconal anaesthesia. Foveal thickness decreased from 691 microm to 239 microm and cysts disappeared by 15 weeks. By 22 weeks, foveal thickness had increased to 282 microm and small cysts had reappeared, but BCVA remained at 0.2 and the number of letters read at 30. CONCLUSION: Proliferative retinopathy regressed, cystoid macular oedema disappeared and vision improved after panretinal photocoagulation and adjuvant intravitreal triamcinolone acetonide injection under intraconal anaesthesia. This represents a feasible option in cases where pain during laser treatment and impairment of vision afterwards due to cystoid macular oedema result in poor compliance with standard laser treatment under topical anaesthesia.

Subthreshold infrared footprinting with indocyanine green for localizing low-intensity infrared photocoagulation.

A novel technique for localizing subthreshold infrared (810 nm) laser treatment and its use in three patients is described. Two patients were treated for choroidal neovascularization with transpupillary thermotherapy or focal subthreshold photocoagulation, and the third patient was treated with grid laser photocoagulation for diabetic macular edema using the 810-nm laser after undergoing indocyanine green angiography for diagnostic purposes. Postoperative indocyanine green images, obtained without reinjection of indocyanine green, revealed areas of hypofluorescence that corresponded to the laser treatment spots. This technique, named subthreshold infrared footprinting, can precisely localize subthreshold infrared laser photocoagulation sites and is potentially useful for evaluating treatment postoperatively and planning additional therapy if necessary.