Randomized trial evaluating short-term effects of intravitreal ranibizumab or triamcinolone acetonide on macular edema after focal/grid laser for diabetic macular edema in eyes also receiving panretinal photocoagulation

PURPOSE

To evaluate 14-week effects of intravitreal ranibizumab or triamcinolone in eyes receiving focal/grid laser for diabetic macular edema and panretinal photocoagulation.

METHODS

Three hundred and forty-five eyes with a visual acuity of 20/320 or better, center-involved diabetic macular edema receiving focal/grid laser, and diabetic retinopathy receiving prompt panretinal photocoagulation were randomly assigned to sham (n = 123), 0.5-mg ranibizumab (n = 113) at baseline and 4 weeks, and 4-mg triamcinolone at baseline and sham at 4 weeks (n = 109). Treatment was at investigator discretion from 14 weeks to 56 weeks.

RESULTS

Mean changes (±SD) in visual acuity letter score from baseline were significantly better in the ranibizumab (+1 ± 11; P < 0.001) and triamcinolone (+2 ± 11; P < 0.001) groups compared with those in the sham group (-4 ± 14) at the 14-week visit, mirroring retinal thickening results. These differences were not maintained when study participants were followed for 56 weeks for safety outcomes. One eye (0.9%; 95% confidence interval, 0.02%-4.7%) developed endophthalmitis after receiving ranibizumab. Cerebrovascular/cardiovascular events occurred in 4%, 7%, and 3% of the sham, ranibizumab, and triamcinolone groups, respectively.

CONCLUSION

The addition of 1 intravitreal triamcinolone injection or 2 intravitreal ranibizumab injections in eyes receiving focal/grid laser for diabetic macular edema and panretinal photocoagulation is associated with better visual acuity and decreased macular edema by 14 weeks. Whether continued long-term intravitreal treatment is beneficial cannot be determined from this study.

VEGF-targeting drugs for the treatment of retinal neovascularization in diabetic retinopathy

Diabetic retinopathy (DR) is the most common microangiopathic complication of diabetes mellitus, representing a major cause of visual impairment in developed countries. Proliferative DR (PDR) represents the last stage of this extremely complex retinal disease, characterized by the development of neovascularization induced by the abnormal production and release of vascular endothelial growth factor (VEGF). The term VEGF includes different isoforms; VEGF-A represents one of the most important pathogenic factors of DR. Anti-VEGF intravitreal therapies radically changed the outcome of DR, due to combined anti-angiogenic and anti-edematous activities. Nowadays, several anti-VEGF molecules exist, characterized by different pharmacological features and duration. With respect to PDR, although anti-VEGF treatments represented a fundamental step forward in the management of this dramatic complication, a big debate is present in the literature regarding the role of anti-VEGF as substitute of panretinal photocoagulation or if these two approaches may be used in combination. In the present review, we provided an update on VEGF isoforms and their role in DR pathogenesis, on current anti-VEGF molecules and emerging new drugs, and on the current management strategies of PDR. There is an overall agreement regarding the relative advantage provided by anti-VEGF, especially looking at the management of PDR patients requiring vitrectomy, with respect to laser. Based on the current data, laser approaches might be avoided when a perfectly planned anti-VEGF therapeutic strategy can be adopted. Conversely, laser treatment may have a role for those patients unable to guarantee enough compliance to anti-VEGF injections.Key messagesVEGF increased production, stimulated by retinal hypoperfusion and ischaemia, is a major pathogenic factor of neovascular complication onset in diabetic retinopathy and of DR stages progression.Nowadays, several anti-VEGF molecules are available in clinical practice and other molecules are currently under investigation. Each anti-VEGF molecule is characterized by different targets and may interact with multiple biochemical pathways within the eye.All the data agreed in considering anti-VEGF molecules as a first line choice for the management of diabetic retinopathy. Laser treatments may have a role in selected advanced cases and for those patients unable to guarantee enough compliance to intravitreal treatments schemes.

Comparison of conventional pattern and novel navigated panretinal photocoagulation in proliferative diabetic retinopathy

PURPOSE

To compare the laser spot quality between the conventional slit lamp pattern laser (PASCAL) and the navigated pattern laser (NAVILAS) for panretinal photocoagulation (PRP).

METHODS

Prospective randomized interventional trial of 73 eyes (51 patients) with high-risk proliferative diabetic retinopathy. Eyes underwent PRP using 30-ms pulse duration with either PASCAL (16 eyes) or NAVILAS laser (21 eyes), or 100-ms pulse duration with either PASCAL (16 eyes) or NAVILAS laser (20 eyes). Fundus color images of all quadrants were taken 5 minutes after treatment. Laser burn size (major and minor diameter and area) and ellipticity (ratio of minor to major axis) were analyzed across the retina. Treatment time and pain were compared between both groups.

RESULTS

The burn size variation in navigated laser 30 ms, 100 ms, and conventional pattern 30 ms and single-spot 100 ms laser was 22%, 24%, 21%, and 35%, respectively. The variation of the laser burn area near the arcade for NAVILAS and for PASCAL was 29% and 22%, respectively (P < 0.01). Closer to the equator, burns from the NAVILAS showed even smaller variation of 15% compared with 25% with PASCAL (P < 0.005). Laser spots from PASCAL exhibited an increasing elliptical shape toward the periphery, whereas NAVILAS laser spots tended to be more uniform all over the retina. Average treatment duration and pain experience was less with navigated laser compared with pattern laser (P ≤ 0.05).

CONCLUSIONS

Navigated laser treatment achieves more uniform laser burns with less pain during shorter treatment duration in comparison with conventional pattern laser.

Evidence-Based Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR) is the most frequent microvascular complication from diabetes and requires annual screening and at least annual follow-up. A systemic approach to optimize blood glucose and blood pressure may halt progression to severe stages of DR and obviate the need for ocular treatment. Although there is evidence of benefit from fenofibrate or intravitreous antiVEGF treatment for eyes with nonproliferative DR (NPDR), these therapies are not standard care for NPDR at this time. Some patients with severe NPDR, especially those with type 2 diabetes, benefit from early panretinal photocoagulation (PRP). Once DR progresses to proliferative DR (PDR), treatment is often necessary to prevent visual loss. PRP remains mainstay treatment for PDR with high-risk characteristics. However, intravitreous antiVEGF injections appear to be a safe and effective treatment alternative for PDR through at least two years. Vitreoretinal surgery is indicated for PDR cases with non-clearing vitreous hemorrhage and/or tractional retinal detachment.

Changes of choroidal thickness after treatment for diabetic retinopathy

PURPOSE

To investigate the choroidal thickness changes after intravitreal bevacizumab injection (IVB), panretinal photocoagulation (PRP) or both for diabetic retinopathy treatment.

MATERIALS AND METHODS

The study included 31 eyes (31 patients) in the IVB group, 35 eyes (35 patients) in the PRP group and 35 eyes (35 patients) in the IVB-PRP group. Enhanced depth imaging optical coherence tomography (EDI-OCT) was performed before and 1 month after each treatment to measure subfoveal and extrafoveal (500 and 1000 μm) choroidal thicknesses. The best-corrected visual acuity (BCVA) and central macular thickness (CMT) were also measured.

RESULTS

The choroidal thickness at all locations significantly decreased after treatment in all groups, but there was no significant difference in the amount of change among the three groups. The subfoveal choroidal thickness and CMT significantly decreased after treatment in the IVB and IVB-PRP groups. In the PRP group, the CMT significantly increased, while the choroidal thickness significantly decreased after treatment. The subfoveal choroidal thickness and CMT were significantly reduced after IVB, but there was no significant correlation between their changes. The BCVA was improved significantly in the IVB and IVB-PRP group, but not in the PRP group.

CONCLUSIONS

The choroidal thickness decreased after all treatments, suggesting that IVB or PRP rapidly reduced choroidal vascular permeability.

Mechanistic Evaluation of Panretinal Photocoagulation Versus Aflibercept in Proliferative Diabetic Retinopathy: CLARITY Substudy

Purpose

The purpose of this study was to study the effects of panretinal photocoagulation (PRP) and intravitreal aflibercept on retinal vessel oxygen saturations, area of retinal nonperfusion, and area of neovascularization in proliferative diabetic retinopathy.

Methods

This is a prospective randomized single center study. Forty patients with proliferative diabetic retinopathy were randomized to PRP or intravitreal aflibercept treatment for 52 weeks. Retinal oximetry and ultra-widefield angiography were performed at baseline and week 52. Ultra-widefield color fundus imaging was performed at baseline, week 12, and week 52. The outcomes were retinal arterio-venous oximetry differences (AVD), area of retinal nonperfusion, and area of neovascularization in disc areas (DA).

Results

The AVD in the PRP group increased from 36.7% at baseline to 39.7%, whereas it decreased from 33.4% to 32.5% in the aflibercept group. The difference in AVD between groups at week 52 was 4.0% (95% confidence interval, -0.08, 8.8; P = 0.10). The baseline mean area of retinal nonperfusion of 125.1 DA and 131.2 DA in the PRP and aflibercept groups increased to 156.1 DA and 158.4 DA, respectively, at week 52 (P = 0.46). The median baseline area of neovascularization decreased from 0.98 DA to 0.68 DA in the PRP group and from 0.70 DA to 0 DA in the aflibercept group at week 12 (P = 0.019). At week 52, this measured 0.24 DA in the PRP group and 0 DA in the aflibercept group (P = 0.45).

Conclusions

Intravitreal aflibercept achieved an earlier and complete regression of neovascularization in proliferative diabetic retinopathy compared with PRP. There were no significant differences in global change in intravascular oxygen saturation or areas of retinal nonperfusion between the two groups by 52 weeks.

American Society of Retina Specialists Clinical Practice Guidelines on the Management of Nonproliferative and Proliferative Diabetic Retinopathy without Diabetic Macular Edema

Purpose

Nonproliferative (NPDR) and proliferative diabetic retinopathy (PDR) without diabetic macular edema (DME) affect millions of individuals living with diabetes throughout the world. There is increasing data on various management strategies for such patients, but there is limited consensus on how the data should be adopted into clinical practice.

Methods

This literature review and editorial presents and synthesizes the current evidence for various management paradigms for NPDR and PDR without DME.

Results

Retina specialists are an integral member of the diabetes management team, and should encourage patients on the importance of glycemic and cardiovascular optimization for both systemic and retinopathy risk factor reduction. The diabetic retinopathy severity scale (DRSS) is now an approvable endpoint for clinical trials in the United States, therefore becoming more clinically relevant. For PDR without DME, the Diabetic Retinopathy Study (DRS) and the Early Treatment Diabetic Retinopathy Study (ETDRS) established the standard of care with panretinal photocoagulation (PRP). Laser parameters have since evolved to include less intense and earlier intervention. Studies have recently demonstrated that anti-vascular endothelial growth factor (VEGF) treatment of PDR is effective at regressing neovascularization and improving DRSS levels in many patients. Further evidence is required to determine optimal treatment frequency, duration, and retreatment criteria, in the real world. There are concerns for adverse events in patients being lost to follow up during anti-VEGF treatment. For NPDR without DME, the standard of care has been a wait-and-watch approach. Data within the DRS and the ETDRS suggest that PRP for severe NPDR can be an option for select patients as well. Multiple clinical trials have now demonstrated that anti-VEGF treatment can improve the DRSS score in NPDR. Further studies are required to assess whether this positively affects long-term visual outcomes, and whether the benefits outweigh the risks in the real world for routine use.

Conclusions

There is cumulative evidence demonstrating the efficacy of various treatment options for NPDR and PDR without DME. Currently, patients would most likely benefit from thoughtful management strategies that are tailored to the individual patient.

Entonox as an analgesic agent during panretinal photocoagulation

BACKGROUND/AIMS

Panretinal photocoagulation (PRP) reduces the risk of visual loss in proliferative diabetic retinopathy but some patients cannot tolerate PRP because of pain. Inhaled Entonox was evaluated as an analgesic during PRP.

METHODS

A randomised, crossover, double masked pilot study was performed. Patients inhaled either air or Entonox and half the PRP was applied. The treatment was completed with the alternate inhaled gas. Patients graded pain experienced during both stages of the treatment using a visual analogue scale. Pain scores were compared using a paired t test.

RESULTS

20 patients participated. Mean pain scores from the Entonox and air treatments were 2.94 (SD 2.73) versus 3.73 (SD 3.20) respectively (p<0.03).

CONCLUSION

Entonox can be used as a safe and effective analgesic agent during PRP treatment.

Intravitreal anti-vascular endothelial growth factors, panretinal photocoagulation and combined treatment for proliferative diabetic retinopathy: a systematic review and network meta-analysis

PURPOSE

To conduct a systematic review with network meta-analysis (NMA) of randomized clinical trials (RCTs) comparing panretinal photocoagulation (PRP) versus anti-vascular endothelial growth factor (VEGF) treatment alone or in combination with PRP, for proliferative diabetic retinopathy (PDR).

METHODS

PubMed, Medline and Embase databases were searched for RCTs comparing PRP versus intravitreal anti-VEGF therapy and/or combined PRP and intravitreal anti-VEGF for PDR. The primary outcome measures were the mean best corrected visual acuity (BCVA) change and the regression of neovascularization. Mean change of central macular thickness (CMT), the subgroup analyses of patients without diabetic macular oedema (DME) and the rate of vitreous haemorrhage and vitrectomy were secondary outcomes. Frequentist NMAs were performed.

RESULTS

Twelve RCTs were included. For the 12-month mean BCVA change, NMA showed a better visual outcome in both the anti-VEGF group and combined group compared to PRP [anti-VEGF vs PRP, mean difference (MD) = 3.42; standard error (SE) = 1.5; combined vs PRP, MD = 3.92; SE = 1.65], with no difference between combined group and anti-VEGF (MD = -0.50; SE = 1.87). No difference in neovascularization regression was found between PRP and anti-VEGF alone or in combination with PRP, but there was significant inconsistency (p = 0.016). Subgroup analyses in patients without DME yielded no difference for the 12-month visual outcome between the three interventions, but with significant inconsistency (p = 0.005).

CONCLUSION

This NMA showed limited evidence of comparable efficacy in terms of neovascularization regression between PRP and anti-VEGF therapy alone or in combination with PRP, but better visual outcomes were associated with anti-VEGF use. Intravitreal anti-VEGF therapy could be a valid therapeutic option in association with PRP.

Effect of panretinal photocoagulation on macular morphology and thickness in eyes with proliferative diabetic retinopathy without clinically significant macular edema

Background

The purpose of this study was to investigate the effect of panretinal photocoagulation (PRP) on macular morphology and thickness in eyes with proliferative diabetic retinopathy (PDR) and without clinically significant macular edema.

Methods

This was a prospective study of 76 eyes from 68 patients diagnosed to have PDR without clinically significant macular edema. Baseline and post PRP visual acuity, morphological changes on optical coherence tomography (OCT), and central foveal thickness were evaluated at one week, one month, and 3 months.

Results

The mean patient age was 56.47 ± 6.55 years. Sixty-two eyes (81.58%) had stable or improved vision, while 14 eyes (18.42%) had worsened visual acuity at 3 months. Compared with baseline, mean visual acuity dropped as early as one week but was regained by 3 months. Mean preoperative central foveal thickness was 222.05 ± 59.11 μm, which increased significantly to 266.84 ± 84.67 μm at one week (P = 0.001), and remained higher at 264.05 ± 102.56 μm by one month (P = 0.01) and 256 ± 101.38 μm by 3 months (P = 0.04). Thirty-four percent of eyes with a normal macula showed morphological changes following PRP. The most common morphological change on OCT after PRP was spongy edema, seen in 48 eyes (31.6%), followed by cystoid macular edema in 36 eyes (23.7%), vitreomacular traction in 28 eyes (18.4%), epiretinal membrane in 24 eyes (15.8%), and subfoveal serous detachment in 16 eyes (10.5%).

Conclusion

PRP may cause a temporary drop in vision in the early post laser phase, and causes macular morphology/thickness changes in eyes with PDR and without clinically significant macular edema. In this study, the change in central foveal thickness did not correlate with a change in visual acuity, and the type of diabetic macular edema on OCT appeared more relevant and correlated better with the visual outcome.

Idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome: clinical perspectives

Idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN) syndrome typically affects young, healthy individuals. Despite the dramatic fundus appearance seen in this syndrome, these patients are usually asymptomatic. The syndrome includes peculiar vascular abnormalities in the form of multiple aneurysmal dilatations seen along retinal arterioles and optic nerve-head arterioles, which are best appreciated on fluorescein angiography. Neuroretinitis and retinal vasculitis are seen in all patients, and manifested by staining of the optic nerve head and diffuse leakage from vessels, mainly arterioles, on fluorescein angiography. The devastating vision-threatening outcomes of this syndrome include exudative retinopathy and extensive peripheral retinal nonperfusion areas, which can eventually lead to neovascularization. This review summarizes current knowledge on the variable clinical aspects of this disease, highlighting diagnostic and treatment strategies.

Laser photocoagulation combined with intravitreal triamcinolone acetonide injection in proliferative diabetic retinopathy with macular edema

PURPOSE

To 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).

METHODS

Visual 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.

RESULTS

Average 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 micrometer to average 279.5-/+34.1 micrometer 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.

CONCLUSIONS

A 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.

Effectiveness of Panretinal Photocoagulation Plus Intravitreal Anti-VEGF Treatment Against PRP Alone for Diabetic Retinopathy: A Systematic Review With Meta-Analysis

OBJECTIVE

To compare the efficacy and safety of panretinal photocoagulation (PRP) combined with intravitreal anti-vascular endothelial growth factor (anti-VEGF) against PRP monotherapy for diabetic retinopathy (DR).

METHODS

We searched Pubmed, Cochrane Library, Web of Science, Embase, and Science Direct Register of Controlled Trials from April 2011 to January 2021 to identify the randomized trials that compared the efficacy and safety between PRP combined with intravitreal anti-VEGF and PRP monotherapy for DR. We searched in the following databases between April 2011 and January 2021: Pubmed, Cochrane Library, Web of Science, Embase, and Science Direct without any restriction of countries or article type. The outcome measures were the best-corrected visual acuity (BCVA), neovascularization on the disc (NVD), neovascularization elsewhere (NVE), central macula thickness (CMT), and total retinal volume over time (FAS), and we also observed the adverse events (AEs) between the two groups.

RESULTS

A total of 351 studies were identified, of which 11 studies were included in this meta-analysis (N = 1,182 eyes). Compared with PRP monotherapy, PRP plus anti-VEGF combination treatment produced a mean reduction in BCVA in units of logMAR of -0.23 [95% CI -0.32, -0.15] or a mean improvement in BCVA in units of letters of 4.99 [95% CI 3.79, 6.19], and also yielded a mean reduction in NVD of -28.41 [95% CI -30.30, -26.52], in NVE of -1.33 [95% CI -1.52, -1.14], in CMT of -1.33 [95% CI -1.52, -1.14], or in total FAS. No significant difference was observed on the risk of AEs as vitreous hemorrhage, elevation in intraocular pressure, and cataract between the two different treatments.

CONCLUSION

PRP with anti-VEGF combination treatment can achieve the ideal efficacy on DR by improving BCVA and NV regression, with no potential increased incidence of AEs, which proves that the combination therapy is an efficient therapeutic strategy that could improve the management of patients with DR.

Anti-Vascular Endothelial Growth Factor Therapy as an Alternative or Adjunct to Pan-Retinal Photocoagulation in Treating Proliferative Diabetic Retinopathy: Meta-Analysis of Randomized Trials

Aim

To compare anti-vascular growth factor (anti-VEGF) pharmacotherapy with pan-retinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR).

Method

PubMed, Embase, Medline, the ClinicalTrials.gov and the Cochrane Central Register of Controlled Trials were reviewed systemically. Randomized controlled trials (RCT) on anti-VEGF therapy versus PRP or anti-VEGF agent combined with PRP versus PRP for PDR are eligible to be included. Outcome measures were regression and recurrence of neovascularization, change in best corrected vision acuity, development of vitreous hemorrhage, and need for vitrectomy. A meta-analysis was conducted using RevMan (Cochrane Collaboration, Oxford, United Kingdom).

Results

Twelve RCTs with a total of 1026 eyes were identified. The meta-analysis results showed that regression of neovascularization did not vary significantly among different treatment regimens (P=0.06), whereas the recurrence of new vessels was significantly lower in PRP monotherapy (P < 0.00001). The best corrected visual acuity was significantly improved with anti-VEGF monotherapy or in the combined group than in the PRP groups (P < 0.00001, P=0.04, respectively). Odds ratio for post-treatment vitreous hemorrhage and vitrectomy rate between anti-VEGF therapy and PRP were 0.65 (95% confidence interval, 0.45–0.95; P = 0.03), and 0.24 (95% confidence interval, 0.12–0.48; P < 0.0001).

Conclusion

Our meta-analysis indicates that anti-VEGF pharmacotherapy is associated with superior visual acuity outcomes and less PDR-related complications. However, there is insufficient evidence to suggest anti-VEGF therapy as an alternative to PRP.

Temporal changes in retinal vascular parameters associated with successful panretinal photocoagulation in proliferative diabetic retinopathy: A prospective clinical interventional study

Purpose

We aimed to investigate changes in retinal vascular geometry over time after panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PDR).

Methods

Thirty‐seven eyes with PDR were included. Wide‐field fluorescein angiography (Optomap, Optos PLC., Dunfermline, Scotland, UK) was used to diagnose PDR at baseline and to assess activity at follow‐up month three and six. At each time‐point, a trained grader measured retinal vessel geometry on optic disc (OD) centred images using semiautomated software (SIVA, Singapore I Vessel Assessment, National University of Singapore, Singapore) according to a standardized protocol.

Results

At baseline, the mean age and duration of diabetes were 52.8 and 22.3 years, and 65% were male. Mean HbA1c was 69.9 mmol/mol, and blood pressure was 155/84 mmHg. Of the 37 eyes with PDR, eight (22%) eyes had progression at month three and 13 (35%) progressed over six months. Baseline characteristics, including age, sex, duration of diabetes, HbA1c, blood pressure, vessel geometric variables and total amount of laser energy delivered did not differ by progression status. However, compared to patients with progression of PDR, patients with favourable treatment outcome had alterations in the retinal arteriolar structures from baseline to month six (calibre, 154.3 μm versus 159.5 μm, p = 0.04, tortuosity 1.12 versus 1.10, p = 0.04) and in venular structures from baseline to month three (fractal dimension 1.490 versus 1.499, p = 0.04, branching coefficient (BC) 1.32 versus 1.37, p = 0.01).

Conclusion

In patients with PDR, successful PRP leads to alterations in the retinal vascular structure. However, baseline retinal vascular geometry characteristics did not predict treatment outcome.

Effect of panretinal photocoagulation on corneal sensation and the corneal subbasal nerve plexus in diabetes mellitus

PURPOSE

To assess the effects of panretinal photocoagulation (PRP) for diabetic retinopathy (DR) on the human corneal subbasal nerve plexus (SBNP) and to investigate correlations between corneal subbasal nerve (SBN) density, corneal sensitivity, and diabetic peripheral neuropathy.

METHODS

Thirty-eight subjects with at least a 10-year history of diabetes mellitus (DM) or DR were included. Subjects were assigned to a PRP group (n = 19), having undergone a treatment of retinopathy in at least one eye or a non-PRP group (n = 19), with no history of PRP. The Michigan Neuropathy Screening Instrument (MNSI) was administered to enable quantification of neuropathic symptoms. Laser scanning in vivo confocal microscopy was performed to capture images of the corneal SBNP to allow determination of SBNP density. Central corneal sensitivity (CST) was evaluated by noncontact aesthesiometry and peripheral vibration perception threshold was measured with a biothesiometer.

RESULTS

Mean SBNP densities were 12.27 ± 4.28 mm/mm²) in the PRP group and 12.75 ± 3.59 mm/mm² in the non-PRP group. There were no significant differences in SBNP density (P = 0.71), CST (P = 0.84), MNSI score (P = 0.19), and biothesiometry (P = 0.77) between the PRP and non-PRP groups. When data from both groups (n = 38) were combined, corneal sensitivity was modestly correlated with SBNP density (r = 0.30, P = 0.06), and peripheral biothesiometry (r = 0.26, P = 0.11).

CONCLUSIONS

In DM correlation of corneal sensitivity, SBNP density, and peripheral biothesiometry may have a potential role in estimating the severity of peripheral neuropathy. Corneal SBNP density and sensitivity appear to be unaffected by PRP laser treatment compared with non-PRP diabetic eyes.

Change in subfoveal choroidal thickness after argon laser panretinal photocoagulation

AIM

To evaluate changes in subfoveal choroidal thickness (SFCT) and macular thickness as measured by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) after argon laser panretinal photocoagulation (PRP) in patients with severe diabetic retinopathy.

METHODS

This prospective, comparative case series included 21 patients (28 eyes) with severe diabetic retinopathy. All patients underwent three sessions of PRP. The SFCT and macular thickness were measured using EDI-OCT at baseline and one week after completion of 3 sessions of PRP.

RESULTS

SFCT before PRP was (318.1±96.5)µm and increased to (349.9±108.3)µm (P=0.001) after PRP. Macular thickness significantly increased at one week after PRP (from 273.1±23.9µm at baseline vs 295.8±25.3µm at one week; P<0.001). No significant relationship between the changes in macular thickness and SFCT was observed (r=-0.13, P=0.52).

CONCLUSION

PRP induced increases in both SFCT and macular thickness. Changes in SFCT did not correlate with changes in macular thickness.

Panretinal photocoagulation versus panretinal photocoagulation plus intravitreal bevacizumab for high-risk proliferative diabetic retinopathy

AIM

To evaluate the effects of panretinal photocoagulation (PRP) compared with PRP plus intravitreal bevacizumab (IVB) in patients with high-risk proliferative diabetic retinopathy (PDR) according to the Early Treatment Diabetic Retinopathy Study criteria.

METHODS

The data were collected retrospectively from the eyes of high-risk PDR patients, which were divided into two groups. After treated with standard PRP, the eyes were randomly assigned to receive only PRP (PRP group) or PRP plus intravitreal injection of 1.25 mg of bevacizumab (PRP-Plus group). Patients underwent complete ophthalmic evaluation, including best corrected visual acuity (BCVA), intraocular pressure (IOP), and new vessel size in fluorescein angiography (FA) and optical coherence tomography for the assessment of central subfield macular thickness (CSMT) at baseline and at weeks 12 (±2), 16 (±2), 24 (±2) and 48 (±2). Main outcome measures also included vitreous clear-up time and neovascularization on the disc (NVD) regression time. Adverse events associated with intravitreal injection were investigated.

RESULTS

Thirty consecutive patients (n=36 eyes) completed the 48-week follow-up. There was no significant difference between the PRP and PRP-Plus groups with respect to age, gender, type or duration of diabetes, area of fluorescein leakage from active neovascularizations (NVs), BCVA or CSMT at baseline. The mean vitreous clear-up time was 12.1±3.4wk after PRP and 8.4±3.5wk after PRP combined with IVB. The mean time interval from treatment to complete NVD regression on FA examination was 15.2±3.5wk in PRP group and 12.5±3.1wk in PRP-Plus group. No significant difference in CSMT was observed between the groups throughout the study period. However, the total area of actively leaking NVs was significantly reduced in the PRP-Plus group compared with the PRP group (P<0.05). Patients received an average of 1.3 injections (range: 1-2). Ten eyes (27.8%) underwent 2 injections. Two eyes had ocular complication of PDR progression to dense vitreous hemorrhage (VH). No major adverse events were identified.

CONCLUSION

The adjunctive use of IVB with PRP is associated with a greater reduction in the area of active leaking NVs than PRP alone in patients with high-risk PDR. Short-term results suggest combined IVB and PRP achieved rapid clearance of VH and regression of retinal NV in the treatment of high-risk PDR. Further studies are needed to determine the effect of repeated intravitreal bevacizumab injections and the proper number of bevacizumab injections as an adjuvant.

Subthreshold microsecond laser for proliferative diabetic retinopathy: a randomized pilot study

Aim

To compare the outcomes of subthreshold microsecond (STM) and continuous-wave laser (CWL) panretinal photocoagulation (PRP).

Methods

In this randomized, prospective, pilot study, 20 eyes of 10 subjects with symmetric severe non-proliferative (NPDR) or low-risk proliferative diabetic retinopathy (PDR) were included. Each eye of the subject was randomized into either CWL or STM PRP group. Patients were evaluated at baseline and at months 3, 6, and 9 with color fundus photographs and visual field tests at each visit; however, electroretinography (ERG) was conducted at baseline and at month 9. The primary outcome measure was the difference in disease progression between the groups. Secondary outcome measures included change in visual acuity, contrast visual acuity, retinal sensitivity on visual field test, and change in ERG parameters.

Results

During the 9-month follow-up, one eye of the STM group progressed to vitreous hemorrhage at the month 6 follow-up and required rescue conventional laser. The CWL group showed a drop in low-contrast visual acuity, visual field index, and scotopic b/a ratio in comparison to the STM group, although the difference was statistically insignificant (p>0.05).

Conclusion

This prospective pilot study proposes microsecond PRP is non-inferior to CWL PRP and could be an alternative to CWL PRP to avoid associated complications in cases of severe NPDR and early PDR.

Long-term Effect of Panretinal Photocoagulation on Spectral Domain Optical Coherence Tomography Measurements in Diabetic Retinopathy

PURPOSE

To evaluate the effects of panretinal photocoagulation on spectral domain optical coherence tomography measurements in diabetic retinopathy by comparing the thicknesses of the central macula, retinal nerve fiber layer, and ganglion cell layer, we used a Cirrus HD OCT® (Carl Zeiss Meditec, Dublin, CA, USA) in normal and diabetic retinopathy cohorts.

METHODS

We analyzed patients who visited our retinal clinic between May 2013 and July 2014. The patients were classified into four groups: normal (Group A), diabetes without diabetic retinopathy (Group B), severe nonproliferative or proliferative diabetic retinopathy (Group C), and at least 3 years after panretinal photocoagulation treatment (Group D). The mean thicknesses of the macula, retinal nerve fiber layer, and ganglion cell layer in each group were compared by measuring a macular cube 512 × 128 scan and an optic disc cube 200 × 200 scan twice.

RESULTS

In total, 154 patients were enrolled. The mean thickness of the central macula in groups A to D was 257.2, 256.8, 257.4, and 255.6 µm, respectively, and did not differ significantly. The mean thickness of the RNFL in group A to D was 96.8, 96.5, 97.2, and 92.8 µm, respectively, and was significantly lower in group D (decreased in the inferior, superior, and nasal sectors, but increased in the temporal). The mean thickness of the ganglion cell layer was also significantly lower in group D (A, 84.5 µm; B, 84.4 µm; C, 82.5 µm; D, 78.5 µm).

CONCLUSIONS

The mean thicknesses of the retinal nerve fiber and ganglion cell layers were decreased significantly in eyes with diabetic eye disease treated with panretinal photocoagulation compared to normal or eyes with diabetic eye disease that had not been laser-treated. Laser treatment might have altered the thickness of the inner layer of the retina, and such changes should be considered in diabetic retinopathy patients after panretinal photocoagulation treatment.

Retinal Nerve Fiber Layer Alterations After Photocoagulation: A Prospective Spectral-Domain OCT Study

PURPOSE

To evaluate the effect of panretinal photocoagulation (PRP) on retinal nerve fiber layer thickness (RNFLT) in treatment-naive patients with proliferative diabetic retinopathy (PDR).

METHODS

Fifty eight previously untreated eyes of 30 patients with PDR who underwent PRP treatment were enrolled prospectively. All patients had at least six months of follow-up. Detailed ophthalmologic examinations including macular thickness and RNFLT assessments with spectral-domain type optic coherence tomography were performed at baseline as well as the third and sixth posttreatment months. Initial RNFLT and macular thickness of laser administered patients were compared with two separate control groups that were consisted of either nondiabetic patients or diabetics without PDR.

RESULTS

The mean age of study patients was 52.4±7.1 years (Range, 32-66 years) and 16 of them (53.3%) were female. At the sixth post-PRP month, visual stabilization or improvement was achieved in 54 eyes (93.1%). No significant difference was demonstrated in initial RNFLT measurements between the study patients and two control groups (p=0.478). Mean RNFLT was measured as 108.5±17.5µm, 115.8±17.6µm, and 103.0±16.4µm at baseline, third and sixth months of the follow-up, respectively. Although RNFLT increase noted at the third post-laser month was statistically significant compared to its baseline values (p<0.001), there was a significant reduction in RNFLT at the sixth post-laser month compared to its baseline values (p<0.001).

CONCLUSION

RNFLT increase in the third month of follow-up may be related to ensuing axonal edema. Significant RNLFT decrease at the sixth month of follow-up may be attributed to axonal loss secondary to the laser treatment.

Vascular endothelial growth factor inhibition and proliferative diabetic retinopathy, a changing treatment paradigm?

Prior to the development of panretinal photocoagulation (PRP) in the 1970s, proliferative diabetic retinopathy (PDR) was the most common cause of blindness in diabetic patients. The diabetic retinopathy study demonstrated that PRP could decrease severe visual loss from PDR by 50%. Since then and for the past four decades, PRP has been the treatment of choice for eyes with PDR. In the past decade, vascular endothelial growth factor (VEGF) inhibition has become the treatment of choice for diabetic macular edema (DME). When treated intensively with anti-VEGF drugs, about one-third of eyes with DME experience an improvement in their diabetic retinopathy severity scale. Randomized clinical trials comparing ranibizumab to PRP and aflibercept to PRP have shown that VEGF inhibitors cause regression of intraocular neovascularization but need to be given on a fairly regular basis. Despite these promising results, concerns about treatment adherence have surfaced. Patients with PDR that are treated solely with anti-VEGF drugs and somehow interrupt their treatment are at a high risk of developing irreversible blindness. Combination treatment of PRP plus an anti-VEGF drug may be the treatment of choice for PDR.

Efficacy and safety of intravitreal ranibizumab with panretinal photocoagulation followed by trabeculectomy compared with Ahmed glaucoma valve implantation in neovascular glaucoma

AIM

To evaluate the efficacy and safety of intravitreal ranibizumab (IVR) with panretinal photocoagulation (PRP) followed by trabeculectomy compared with Ahmed glaucoma valve (AGV) implantation in neovascular glaucoma (NVG).

METHODS

This was a retrospective comparative study. We reviewed the cases of a total of 45 eyes from 45 NVG patients among which 23 eyes underwent AGV implantation and the other 22 underwent trabeculectomy. The causes of neovascular glaucoma included: diabetic retinopathy (25 eyes), and retinal vein occlusion (20 eyes). All patients received preoperative IVR combined with postoperative PRP. The mean best-corrected visual acuities (BCVA) were converted to the logarithms of the minimum angle of resolution (logMAR) for the statisitical analyses. Intraocular pressure (IOP), the logMAR BCVA and surgical complications were evaluated before and after surgery. The follow-up period was 12mo.

RESULTS

A total of 39 cases showed complete regression of iris neovascularization at 7d after injection, and 6 cases showed a small amount of residual iris neovascularization. The success rates were 81.8% and 82.6% at 12mo after trabeculectomy and AGV implantation, respectively. In the trabeculectomy group, the logMAR BCVA improved at the last follow-up in 14 eyes, remained stable in 6 eyes and decreased in 2 eyes. In 4 cases, slight hyphemas developed after trabeculectomy. A shallow anterior chamber developed in 2 cases and 2 vitreous hemorrhages. In the AGV group, the logMAR BCVA improved in 14 eyes, remained stable in 5 eyes and decreased in 4 eyes. Slight hyphemas developed in 3 cases, and a shallow anterior chamber in 3 cases. The mean postoperative IOP was significantly lower in both groups after surgery (F=545.468, P<0.05), and the mean postoperative logMAR BCVA was also significantly improved (F=10.964, P<0.05) with no significant difference between two groups.

CONCLUSION

It is safe and effective to treat NVG with this combined procedure, and we found similar results after IVR+AGV implantation+PRP and IVR+trabeculectomy+PRP in eyes with NVG.

Electroretinogram Changes Following Sequential Panretinal Photocoagulation for Proliferative Diabetic Retinopathy

Purpose

To evaluate changes in electroretinogram (ERG) response over the course of multiple sessions of panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PRP).

Methods

A prospective cohort study of 11 patients with PDR who required PRP was conducted. PRP was completed over three sessions. Each patient had five ERGs done: baseline, 1 week after each PRP session, and 6 weeks after the last session of PRP. Dark-adapted 0.01 ERG, Dark-adapted 3 ERG, Dark-adapted 10 ERG, Light- adapted 3 ERG, and Light-adapted 30 Hz flicker ERG were done. The mean change in a- and b-wave amplitudes as well as implicit times compared to baseline was analyzed.

Results

A significant reduction in peak amplitudes of both a- and b-waves and delay in latencies were observed in all responses (p<0.05). The absolute amplitude reduction and delay in latency were higher for scotopic b-waves (p<0.05). The root mean square (RMS) of Dark-adapted 10.0 ERG (p<0.05) and total mean amplitude changes of a- and b-waves (p<0.001) were reduced after each laser session; however, the magnitude of change was not different between the first, second, or third sessions of PRP, and each session showed a similar deterioration rate of ERG parameters comparing to each other (p=0.4 for RMS and p=0.2 for total mean amplitude changes). In addition, the results indicated recovery of the amplitude and latency of ERG waves after 6 weeks from the final treatment (p<0.001) although not to baseline levels.

Conclusion

ERG findings following PRP show reduced retinal function after each session which partially recovers by 6 weeks after the completion of therapy. Clinicians should be mindful of these changes when planning the treatment course for patients with PDR.

Simultaneous pars plana vitrectomy, panretinal photocoagulation, cryotherapy, and Ahmed valve implantation for neovascular glaucoma

AIM

To describe and evaluate the efficacy of Ahmed glaucoma valve implantation (AGV) combined with pars plana vitrectomy (PPV) in a single surgical act for the treatment of advanced neovascular glaucoma (NVG).

METHODS

Retrospective observational case series included 51 eyes from 50 patients with severe NVG treated with PPV, AGV, and panretinal photocoagulation and/or cryotherapy in a single surgical act during a 13-year period (2005-2018). Preoperative, intraoperative and postoperative data at day 1 and months 1, 3, 6, 21, and 24 were systematically collected. Definition of surgical success was stablished at IOP between 6 and 21 mm Hg with or without topical treatment.

RESULTS

Main indications for surgery were NVG secondary to proliferative diabetic retinopathy (39.2%) and central retinal vein occlusion (37.3%). Mean (±SD) preoperative IOP was 42.0±11.2 mm Hg decreasing to 15.5±7.1 mm Hg at 12mo and 15.8±9.1 mm Hg at 24mo of follow up. Cumulative incidence of success of IOP control was 76.0% at first postoperative month, reaching 88.3% at 6mo. Prevalence of successful IOP control at long term was 74.4% at 12mo and 71.4% at 24mo. Eye evisceration for unsuccessful NVG management was required in 1 case (2.0%).

CONCLUSION

Combination of AGV implantation and PPV in a single act may be a suitable option for severe forms of NVG in a case-by-case basis for effective IOP control and a complete panretinal photocoagulation.