Long-term Outcomes of Pan-retinal Laser Photocoagulation in Retinal Vascular Disorders: A Systematic Review

Anterior chamber depth and intraocular pressure following panretinal argon laser photocoagulation for diabetic retinopathy

Proliferative diabetic retinopathy is treated with panretinal photocoagulation, which improves the visual prognosis in this complication considerably. The visual acuity (VA) and grade of retinopathy before treatment are known indicators of the visual prognosis after treatment, but the prognostic value of other clinical background and treatment parameters is unknown. The study reports predictors for visual outcome identified among retrospective clinical background data and treatment parameters from 4422 panretinal photocoagulation sessions for proliferative diabetic retinopathy in 1013 eyes of 601 patients performed at the Department of Ophthalmology, Arhus University Hospital between 1985 and 2002. High pretreatment VA and low age were strong positive predictors of post-treatment VA (p < 0.0001). However, diabetes type, diabetes duration and calendar year of treatment showed no influence on post-treatment VA (p = 0.7829, 0.1782, and 0.3747, respectively). The visual prognosis was inversely related to the number of treatment sessions (p = 0.0259) and the number of vitrectomies (OR = 2.66 [1.24; 5.69], p = 0.0117, for more than two operations). However, the visual prognosis was unrelated to any of the other parameters studied. Pretreatment VA, age and the number of panretinal photocoagulation treatment sessions and vitrectomies necessary to halt the disease are indicators of the visual prognosis after panretinal laser photocoagulation for proliferative diabetic retinopathy.

To report short-term regression of neovascularization after varying intravitreal doses of bevacizumab (Avastin®; Genentech, San Francisco, California, USA) in patients with proliferative diabetic retinopathy (PDR). Eighty eyes from 76 patients with active neovascularization of the disc (NVD) or elsewhere (NVE) caused by PDR were divided into four groups and treated with a single intravitreal bevacizumab (IVB) injection of 1.25 mg, 600 μg, 300 μg or 150 μg, respectively. All patients underwent ophthalmoscopic examination and fluorescein angiography at baseline, 1 week, 1 month and 2 months later. No significant ocular or systemic adverse events were observed. In all patients with NVD or NVE, complete resolution of leakage was recorded within the first week or the first month of the injection. Even with the lowest dose (150 μg), regression of neovascularization appeared as early as the first week and lasted for over a month. Recurrence of fluorescein leakage was observed in all groups after the first month and did not correlate with the extent of neovascularization or IVB dose. Short-term results suggest that IVB given below the standard dosage (150–300 μg compared to 1.25 mg) can lead to the achievement of complete regression of diabetic retinal neovascularization within 30–45 days of injection.

To establish safe laser parameter standards for 10-30 ms Pascal(®) laser in clinical practice and to evaluate clinical and visual outcomes using this 532-nm multi-spot photocoagulation system. Retrospective observational case series of 313 patients treated between 2006 and 2008. Evaluation of eight groups: A - panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR); B - focal laser treatment for clinically significant diabetic macular oedema; C - grid laser for diffuse diabetic macular oedema; D - sector PRP for ischaemic branch retinal vein occlusions (I-BRVO); E - full PRP for ischaemic central retinal vein occlusions (I-CRVO); F - macular laser treatment for macular oedema secondary to non-ischaemic BRVO; G - full PRP for rubeosis iridis and/or neovascular glaucoma (NVG) secondary to I-BRVO, I - CRVO or PDR; H - laser retinopexy for retinal breaks/degenerations. Mean LogMAR visual acuity for all procedures improved postlaser (p = 0.065), and laser prevented visual loss in 85% eyes. Topical anaesthesia was only required. At mean follow-up of 5 months, 72% procedures had a successful clinical outcome. Significantly higher powers were required for PRP using Pascal(®) compared to conventional laser (p = 0.001) in PDR, I-BRVO, I-CRVO and NVG. Sixty-seven per cent of patients (15/20) were successfully treated with single-session 20-ms PRP using a mean 1952 burns. There were no laser-associated adverse effects or ocular complications associated with multi-spot PRP or macular Pascal(®) arrays. The clinical efficacy using 10- to 30-ms pulse duration Pascal(®) laser is comparable to conventional standard protocols used for the treatment of vascular retinal disorders. Higher power, 10- to 30-ms pulse duration laser may be safely and effectively used in clinical practice.

Different lasers and techniques for proliferative diabetic retinopathy.

Panretinal photocoagulation (PRP) is the current standard of care in proliferative diabetic retinopathy (PDR). However, treatment with anti-vascular endothelial growth factor agents might offer better patient outcomes with fewer side-effects. The PRIDE study aimed to assess the efficacy and safety of ranibizumab with or without PRP compared with PRP alone in patients with PDR. A total of 106 PDR patients without diabetic macular oedema were randomized to receive ranibizumab 0.5mg monotherapy (n=35), PRP (n=35) or combined ranibizumab 0.5mg/PRP (n=36). The primary objective of this 12-month, multicentre, phase II study was to investigate the change in area of retinal neovascularization (NV). Complete regression of leakage and best-corrected visual acuity (BCVA) were key secondary end-points. At Month 12, there was a statistically significant difference of -2.83mm² in the least square mean change in NV area between the ranibizumab monotherapy and PRP group, favouring ranibizumab (95% CI [-5.45; -0.21], p=0.0344). At Month 3, 67%/0%/67% of the patients in the ranibizumab/PRP/combination groups, respectively, showed complete regression of leakage from NVs, while at Month 12, 28%/8%/18% showed complete regression of leakage from NVs. BCVA change was greater in the ranibizumab group compared with the PRP monotherapy group at Month 12 (+1.6 letters; 95% CI [-2.3; 5.5] versus -3.9 letters; 95% CI [-7.8; -0.1], p=0.0495). Ranibizumab monotherapy is an alternative treatment option to laser treatment in patients with PDR. Ranibizumab showed stronger effects on NV leakage and area reduction while offering better visual acuity results than PRP alone.

BackgroundDuring panretinal photocoagulation (PRP), the outer retina, especially the photoreceptors, are destroyed. During such procedures, the impact of the retinal photocoagulation, which is performed in the same photocoagulated area, may change if it is applied to different locations with different photoreceptor densities. Thus, we aimed to evaluate the influence of photoreceptor density on PRP.MethodsWe constructed a three-dimensional (3D) average distribution of photoreceptors with 3D computer-aided design (CAD) software using previously derived photoreceptor density data and calculated the number of photoreceptors destroyed by scatter PRP and full-scatter PRP (size 400-μm on the retina, spacing 1.0 spot) using a geometry-based simulation. To investigate the impact of photoreceptor density on PRP, we calculated the ratio of the number of photoreceptors destroyed to the total number of photoreceptors, termed the photoreceptor destruction index.ResultsIn this 3D simulation, the total number of photoreceptors was 96,571,900. The total number of photoreceptors destroyed by scatter PRP and full-scatter PRP were 15,608,200 and 19,120,600, respectively, and the respective photoreceptor destruction indexes were 16.2 and 19.8%, respectively.ConclusionsScatter PRP is expected to have 4/5 of the number of photoreceptors destroyed by full-scatter PRP.

Oral versus Topical Diclofenac for Pain Prevention during Panretinal Photocoagulation

This study was performed to utilize transnasal Sphenopalatine Ganglion (SPG) block for pain reliving during panretinal photocoagulation (PRP) in diabetic patients with diabetic retinopathy. This pre and post interventional study was performed on 20 patients with proliferative diabetic retinopathy. The first PRP treatment session of all the patients is performed with no transnasal SPG block, but before holding the second session, all the patients underwent transnasal SPG block and pain levels during and after PRP were compared to each other. Before the transnasal SPG block, each nostril of all the cases was inspected for finding any obstruction in each PRP session. Transnasal SPG block was also performed in with 2% lidocaine. The mean age of the included cases was 52.84 ± 8.62 years old (from 36 to 72 years old). All the cases underwent two PRP lasers treatment sessions with the same characteristic (spot size, power and duration) for each patient. In the first and second PRP treatment sessions, the mean NRS scores were obtained immediately after the PRP laser (8.4 vs. 4.2), 15 min (8.2 vs. 4.2), 1 h (8.0 vs. 4.1), and 24 h (5.4 vs. 3.6) after the PRP respectively. The mean NRS scores significantly reduced during the second PRP treatment session compared to the first session (p < 0.001). Transnasal SPG block is a safe and effective strategy used for relieving pain caused by the PRP laser treatment in patients with diabetic retinopathy.

Panretinal laser photocoagulation decreases large foveal avascular zone area in non-proliferative diabetic retinopathy: A prospective OCTA study

PurposeTo evaluate therapeutic effects and usefulness of a combination treatment of intravitreal injection of triamcinolone acetonide (IVTA) and panretinal photocoagulation (PRP) in patients with clinically significant macular edema secondary to proliferative diabetic retinopathy (PDR).MethodsVisual acuity test, fundoscopy, fluorescein angiography, and optical coherence tomography (OCT) were taken in 20 patients (20 eyes) of macular edema and PDR. A combination of intravitreal injection of triamcinolone acetonide and PRP was performed in 10 patients (10 eyes) and a combination of focal or grid laser photocoaqulation and PRP in the remaining 10 eyes. The postoperative outcomes were compared between the two combination treatments by best corrected visual acuity (BCVA), tonometry, fluorescein angiography, and OCT at 2 weeks, 1, 2, and 3 months.ResultsAverage BCVA (log MAR) significantly improved from preoperative 0.56±0.20 to 0.43±0.08 at 1 month (P=0.042) and it was maintained until 3 months after a combination of IVTA and PRP in 10 eyes (P=0.007). The thickness of fovea decreased from average 433.3±114.9 µm to average 279.5±34.1 µm at 2 weeks after combined treatment of IVTA and PRP (P=0.005), which was significantly maintained until 3 months, but there was a transient visual disturbance and no significant difference in thickness of the fovea before and after treatment in the groups with PRP and focal or grid laser photocoagulation.ConclusionsA combination of IVTA and PRP might be an effective treatment modality in the treatment of macular edema and PDR and prevent the subsequent PRP-induced macular edema result in visual dysfunction. In combination with PRP, IVTA might be more effective than focal or grid laser photocoagulation and PRP for reducing diabetic macular edema and preventing aggravation of macular edema without transient visual disturbance in patients requiring immediate PRP.

The Effect of Pan-Retinal Photocoagulation on Rubeosis Iridis

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Background/AimsProliferative diabetic retinopathy (PDR) is a severe blinding condition. We investigated whether retinal metabolism, measured by retinal oximetry, may predict PDR activity after panretinal laser photocoagulation (PRP).MethodsWe performed a prospective,...

Thirteen young diabetic patients with peripheral capillary non perfusion who presented with symptoms of mild maculopathy were reviewed retrospectively. In this group, peripheral retinal ischaemia was often overlooked and a rapidly progressive proliferative retinopathy developed. Fluorescein angiography of the peripheral retina showed capillary closure, but with preservation of arterioles and venules. In this series, half of the eyes lost vision. In seven eyes where the peripheral ischaemia was treated by pan retinal photocoagulation, the maculopathy resolved without any specific laser treatment to the macula. In young diabetics presenting with maculopathy, the peripheral retina should be examined for ischaemia, and if present, pan retinal laser photocoagulation should be performed. Focal treatment for the macular disease can be delayed until after the peripheral photocoagulation, as the maculopathy may remit.