Panretinal Photocoagulation Using Short-Pulse Laser Induces Less Inflammation and Macular Thickening in Patients with Diabetic Retinopathy

Characterization of the visually impaired patients with diabetes mellitus in Japan

AIMS/INTRODUCTION

To conduct a multicenter survey of visually impaired patients with diabetes mellitus (DM) and to identify the physical and ocular characteristics that lead to blindness in Japan.

MATERIALS AND METHODS

Visually impaired patients with diabetes mellitus in Japan were divided into blind and low-vision groups according to the World Health Organization classification. Data on parameters related to diabetes mellitus and ocular complications in the right and left eyes were collected from 19 highly advanced medical facilities and compared between the two groups.

RESULTS

Among 408 visually impaired persons (blind group: 257, low-vision group: 151), 72.1% were under 70 years of age. The rates of neovascular glaucoma (NVG) (right eye, P = 0.041; left eye, P = 0.0031) or proliferative diabetic retinopathy (PDR) (right eye: P = 0.014, left eye: P = 0.0047) and the rate of proliferative membrane beyond half of the retinal area (right eye: P = 0.0263, left eye: P = 0.037) were significantly higher in the blind group. The direct cause of visual impairment was retinal atrophy, common in both groups. Neovascular glaucoma and diabetic macular edema were equally prevalent in the blind and low-vision groups, respectively.

CONCLUSIONS

In Japan, blind patients with diabetes mellitus are characterized by severe conditions such as neovascular glaucoma and progressive proliferative diabetic retinopathy upon their initial visit to an advanced care facility. These results highlight the importance of monitoring retinopathy through regular ophthalmological examinations, internal medicine, and appropriate therapeutic intervention.

Long-term longitudinal retinal changes after conventional and pattern scan laser panretinal photocoagulation in diabetic retinopathy

PURPOSE

Comparison the effect of conventional and pattern scan laser (PASCAL) panretinal photocoagulation (PRP) on macula and optic disk in diabetic retinopathy (DR).

METHODS

This retrospective study included 57 patients. In the conventional laser group, PRP was completed using the LightMed LightLas 532 laser device in accordance with the ETDRS protocol. In the pattern laser group, it was completed in a single session using PASCAL device with 20 ms pulse duration and multispot pattern. Central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness were evaluated before laser treatment and at 1, 6 and 12 months after treatment.

RESULTS

There were 30 eyes in the conventional laser group and 27 eyes in the PASCAL group. There was no significant difference between the groups in terms of age (p = 0.560), sex (p = 0.866), duration (p = 0.498) and stage (p = 0.503) of diabetes, visual acuity (p = 0.104) and intraocular pressure (p = 0.963).In both groups, CMT increased significantly (p ˂0.001), while RNFL thickness decreased significantly (p ˂0.001) at 12 months. While CMT and mean RNFL thickness increased in the first month in both groups, it decreased progressively until the 12th month.

CONCLUSION

Conventional and pattern laser systems used in the treatment of DR................ cause an increase in CMT and thinning of RNFL thickness in the long term. This change is more in the conventional laser group compared to the pattern laser.

Quantitative Evaluation of Fundus Autofluorescence in Laser Photocoagulation Scars for Diabetic Retinopathy: Conventional vs. Short-Pulse Laser

Short-pulse laser is popular for its advantages like less pain. However, its effectiveness is still debated. The aim of this study was to compare fundus autofluorescence (FAF) luminosity changes of laser photocoagulation scars between the conventional laser (0.2 s) and the short-pulse laser (0.02 s) for diabetic retinopathy. Conventional and short-pulse laser photocoagulations were performed in six and seven eyes, respectively. FAF images were captured at 1, 3, 6, 12, and 18 months after the treatments. To evaluate FAF, individual gray-scale values of the laser scars adjacent to the retinal arcade vessels were recorded; then, the mean gray values of the scars were divided by the luminosity of arcade vein. The average luminosity ratio of laser scars at 1, 3, 6, 12, and 18 months were 1.51 ± 0.17, 1.26 ± 0.07, 1.21 ± 0.03, 0.95 ± 0.11, and 0.89 ± 0.05 with conventional laser and 1.91 ± 0.13, 1.50 ± 0.15, 1.26 ± 0.08, 1.18 ± 0.06, and 0.97 ± 0.04 with short-pulse laser, respectively. Findings suggest the short-pulse laser displayed delayed hypoautofluorescence progression. This implies potential postponement in post-irradiation atrophic changes, as well as metabolic amelioration delay in the ischemic retina, when compared to conventional laser treatment.

The Role of Laser Photocoagulation in Treating Diabetic Macular Edema in the Era of Intravitreal Drug Administration: A Descriptive Review

Background and Objectives: This study aimed to elucidate the role of laser photocoagulation therapy in the treatment of diabetic macular edema (DME) as an alternative to, or in conjunction with, the first-line treatment, anti-vascular endothelial growth factor (VEGF). Materials and Methods: A comprehensive literature search to identify studies that evaluated the efficacy of laser photocoagulation therapy in the management of DME was performed. The relevant findings of the efficacy of focal/grid laser therapy from data in randomized, controlled trials were synthesized, and the potential of new laser technologies, such as navigated laser systems, pattern scan lasers, and subthreshold lasers, was explored. The usefulness of multimodal imaging-guided laser therapy was also evaluated, with a focus on the potential contribution to anti-VEGF therapy. Results: Focal laser photocoagulation targeting microaneurysms remains an effective therapeutic approach to chronic refractory edema, despite the widespread use of anti-VEGF therapy. To achieve the best possible treatment outcomes, precise identification of microaneurysms is essential. This requires the use of multimodal imaging-guided, highly accurate, minimally invasive coagulation techniques. Subthreshold laser therapy can also reduce the frequency of anti-VEGF injections and minimize treatment burden. Conclusions: Further studies are needed to determine the optimal timing and settings for laser photocoagulation therapy and the potential of new laser technologies in the management of DME. Nevertheless, laser photocoagulation therapy plays an important role in the management of DME, in conjunction with anti-VEGF therapy.

Updates on the Current Treatments for Diabetic Retinopathy and Possibility of Future Oral Therapy

Diabetic retinopathy (DR) is a complication of diabetes and one of the leading causes of vision loss worldwide. Despite extensive efforts to reduce visual impairment, the prevalence of DR is still increasing. The initial pathophysiology of DR includes damage to vascular endothelial cells and loss of pericytes. Ensuing hypoxic responses trigger the expression of vascular endothelial growth factor (VEGF) and other pro-angiogenic factors. At present, the most effective treatment for DR and diabetic macular edema (DME) is the control of blood glucose levels. More advanced cases require laser, anti-VEGF therapy, steroid, and vitrectomy. Pan-retinal photocoagulation for non-proliferative diabetic retinopathy (NPDR) is well established and has demonstrated promising outcomes for preventing the progressive stage of DR. Furthermore, the efficacy of laser therapies such as grid and subthreshold diode laser micropulse photocoagulation (SDM) for DME has been reported. Vitrectomy has been performed for vitreous hemorrhage and tractional retinal detachment for patients with PDR. In addition, anti-VEGF treatment has been widely used for DME, and recently its potential to prevent the progression of PDR has been remarked. Even with these treatments, many patients with DR lose their vision and suffer from potential side effects. Thus, we need alternative treatments to address these limitations. In recent years, the relationship between DR, lipid metabolism, and inflammation has been featured. Research in diabetic animal models points to peroxisome proliferator-activated receptor alpha (PPARα) activation in cellular metabolism and inflammation by oral fenofibrate and/or pemafibrate as a promising target for DR. In this paper, we review the status of existing therapies, summarize PPARα activation therapies for DR, and discuss their potentials as promising DR treatments.

Efficacy and safety of qiming granule combined with laser in the treatment of diabetic retinopathy: A protocol of randomized controlled trial

BACKGROUND

Diabetic retinopathy is not only the most common complication of diabetes, but also 1 of the main causes of blindness, which seriously affects the physical and mental health of patients. Panretinal photocoagulation is a common method for the treatment of diabetic retinopathy, but it has some defects. Qiming granule has advantages in the treatment of diabetic retinopathy, but there is a lack of standard clinical research to verify it. Therefore, the purpose of this randomized controlled trial is to evaluate the efficacy and safety of qiming granule combined with laser in the treatment of diabetic retinopathy.

METHODS

This is a prospective randomized controlled trial to study the efficacy and safety of Qiming granule combined with laser in the treatment of diabetic retinopathy. Approved by the Clinical Research Society of our hospital. The patients are randomly divided into a treatment group (Qiming granule combined with laser treatment group) or control group (simple laser treatment group). The patients are followed up for 12 months after 6 months of treatment. Observation indexes include total effective rate, corrected visual acuity, macular fovea thickness, adverse reactions and so on. Data are analyzed using the statistical software package SPSS version 18.0 (Chicago, IL).

DISCUSSION

This study will evaluate the clinical efficacy and safety of qiming granule combined with laser in the treatment of diabetic retinopathy. The experimental results of this study will provide a reliable reference basis for clinical use of qiming granule combined with laser in the treatment of diabetic retinopathy.

TRIAL REGISTRATION

OSF Registration number: DOI 10.17605/OSF.IO/ZEQPB.

Effect of intravitreal or sub-tenon triamcinolone acetonide injection at completion of vitrectomy on peripheral retinochoroidal thickness in eyes with proliferative diabetic retinopathy

The effect of triamcinolone acetonide (TA) on the peripheral retinochoroidal thickness was determined after pars plana vitrectomy (PPV) with scatter photocoagulation in eyes with proliferative diabetic retinopathy. The peripheral retinochoroidal thickness was measured at 5 mm from the limbus in the four quadrants using anterior segment optical coherence tomography before, and 3 days, and 1 and 2 weeks after the surgery. The total peripheral thickness was significantly thicker than the baseline thickness after PPV alone (P < 0.001; 18 eyes), PPV combined with intravitreal TA injection (IVTA; P = 0.011; 19 eyes), and PPV combined with sub-tenon TA injection (STTA; P = 0001; 23 eyes). The total peripheral thickness in the PPV group at 3 days after surgery was significantly thicker than that of the PPV + IVTA (P = 0.015) and of the PPV + STTA groups (P = 0.016). Multiple linear regression analyses showed that the injection of TA by the two routes and the number of photocoagulation burns were significantly correlated with the total peripheral thicknesses at 3 days after the surgery. The results indicate that the PPV with large number of intraoperative scatter photocoagulation burns caused an increase in the total peripheral thickness and an administration of either IVTA and STTA can reduced the degree of thickening.

Posterior subtenon infusion of triamcinolone acetonide as adjunctive treatment to panretinal photocoagulation using pattern scan laser for diabetic retinopathy

PURPOSE

To estimate the effect of sub-Tenon's capsule triamcinolone acetonide injection (STTA) combined with panretinal photocoagulation (PRP) using pattern scan laser (PSL) for high risk non-proliferative diabetic retinopathy (NPDR), in terms of the inflammation and the progression of diabetic macular edema (DME).

STUDY DESIGN

Retrospective comparative analysis.

METHODS

NPDR patients who underwent PRP using PSL with (STTA+PSL group, n=24) or without (PSL group, n=19) pretreatment of STTA were enrolled. We measured anterior flare intensity (AFI) and central retinal thickness (CRT) at day of STTA (day 0), and at 1, 3, 7, 11 and 15 weeks.

RESULTS

The CRT of the STTA+PSL group was significantly lower than that of the PSL group at 7 (308.15±69.16 μm versus 340.21±77.91 μm, p = 0.04), 11 (283.8±60.75 μm versus 335.7±67.70 μm, p = 0.01) and 15 weeks (281.13±35.29 μm versus 316.58±54.89 μm, p = 0.02). AFI levels in the STTA+PSL group were significantly lower than those in the PSL group at 11 (10.47±3.40 versus 15.85±8.38, p = 0.007) and 15 weeks (11.38±3.31 versus 14.37±3.85, p = 0.009). The significant improvement in CRT from baseline was noticed through the observational periods in STTA+PSL group, but not in the PSL group.

CONCLUSION

Pretreatment of STTA has the potential to not only prevent the worsening of DME, but also reduce the CRT and AFI of eyes with NPDR after PRP using PSL.

Effect of 0.05% Difluprednate Ophthalmic Emulsion on Proinflammatory Cytokine Levels After Retinal Laser Photocoagulation in Rabbits

PURPOSE

We aimed to evaluate the effect of the topical application of a strong corticosteroid, difluprednate, on the levels of inflammatory and angiogenic cytokine in the vitreous and aqueous humor after laser photocoagulation.

METHODS

Pigmented rabbits were treated with retinal laser photocoagulation and divided into 4 groups, namely control (no additional treatment), topical application of difluprednate 0.05%, betamethasone sodium phosphate 0.1%, and sub-Tenon injection of triamcinolone acetonide (STTA). Samples of vitreous and aqueous humor were collected on posttreatment days 0, 1, 7, and 14. The levels of intraocular vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemotactic protein-1 (MCP-1) were measured using an immunoassay. Intraocular pressure (IOP) was monitored in each group.

RESULTS

VEGF, IL-6, ICAM-1, and MCP-1 were significantly elevated on day 1 and were reduced in both the vitreous and aqueous humor following topical application of difluprednate and STTA. Topical betamethasone reduced their levels in the aqueous humor but not in the vitreous. A significant increase of IOP induced by difluprednate returned to control levels after withdrawal of administration.

CONCLUSION

Although the elevation of IOP was an expected, manageable side effect, topical application of difluprednate was more effective than STTA and betamethasone for reducing inflammatory cytokine levels after laser treatment.

Less Expansion of Short-Pulse Laser Scars in Panretinal Photocoagulation for Diabetic Retinopathy

Purpose

To compare the expansion rates of laser photocoagulation scars between the conventional laser and short-pulse laser using fundus autofluorescence (FAF).

Methods

Retrospective chart review. Conventional laser was performed on 6 eyes of 6 patients, and short-pulse laser was performed on 11 eyes of 8 patients with diabetic retinopathy. FAF images were obtained by Optos® 200Tx (Optos, Dunfermline, Scotland, UK) at 1, 3, 6, and 12 months after treatment. The average area of 20 photocoagulation scars was measured by using ImageJ software. The expansion rates were calculated from the proportion of the averaged area against the optic disc area. Regression of retinopathy and central macular thickness were also evaluated.

Results

The expansion rates of the conventional laser scars compared with the size at 1 month after treatment were 1.12 ± 0.08 (3 M), 1.27 ± 0.12 (6 M), and 1.39 ± 0.11 (12 M). The expansion rates of the short-pulse laser scars were 1.04 ± 0.05 (3 M), 1.09 ± 0.04 (6 M), and 1.13 ± 0.05 (12 M). The expansion rates of the short-pulse laser were significantly lower than those of the conventional laser (p < 0.01).

Conclusion

FAF images were useful to evaluate the changes in the photocoagulation scar sizes. The scars with the short-pulse laser showed lower expansion rates than those of the conventional laser.

Effect of intravitreal triamcinolone acetonide injection at the end of vitrectomy for vitreous haemorrhage related to proliferative diabetic retinopathy

Background/Aims

To investigate whether intravitreal injection of triamcinolone acetonide (IVTA) combined with vitrectomy prevents postoperative inflammation in patients with vitreous haemorrhage (VH) due to proliferative diabetic retinopathy (PDR).

Methods

This prospective, multicentre, randomised study conducted at seven sites in Japan enrolled patients diagnosed as having VH following PDR. Patients underwent vitrectomy with (IVTA+VIT group) or without (VIT group) IVTA at the end of the surgery. Anterior flare intensity (AFI), central retinal thickness (CRT), best-corrected visual acuity (BCVA) and intraocular pressure (IOP) were measured before and at 3 days, 1 week, 1, 3 and 6 months after surgery and compared.

Results

Number of patients who completed 6 months of follow-up was 40 and 41 in VIT group and IVTA+VIT group, respectively. AFI was significantly higher in the VIT group than in the IVTA+VIT group at 3 days (P=0.033), 1 week (P=0.019) and 1 month (P=0.037). There were no significant differences in CRT, BCVA and IOP between the groups through the observational periods. In the cases with macular oedema >350 µm of CRT at 3 days, CRT was significantly lower in the IVTA+VIT group than in the VIT group at 1 month (P=0.041).

Conclusions

IVTA combined with vitrectomy and cataract surgery contributed to inhibit the postoperative inflammation in patients with VH due to PDR. The effect of IVTA in the reduction of diabetic macular oedema may be limited to the early stage after surgery.

Trial registration number

UMIN000020376, Post-results.