Optos-guided pattern scan laser (Pascal)-targeted retinal photocoagulation in proliferative diabetic retinopathy

Laser Treatment for Diabetic Retinopathy: History, Mechanism, and Novel Technologies

Background: Diabetic retinopathy (DR), as a complication of diabetes mellitus (DM), remains a significant contributor to preventable vision impairment in the working-age population. Laser photocoagulation is essential in treating DR in conjunction with anti-vascular endothelial growth factor (VEGF) injection, steroids, and vitrectomy. This review summarizes the history of laser photocoagulation and highlights its current role and long-term effectiveness in real-world conditions. Methods: The National Clinical Trial (NCT), PubMed, Google Scholar, and China National Knowledge Infrastructure (CNKI) databases were searched utilizing combined or individual keywords, and a total of 121 articles were reviewed by the authors. Results: Several novel laser photocoagulation technologies, such as patterned scanning laser, subthreshold micropulse laser, navigated laser, multimodal imaging-guided laser, and retina rejuvenation therapy, substantially decrease the adverse effects and improve the accuracy and security of laser therapy. Numerous studies have demonstrated the outstanding clinical efficacy of combination therapies with pharmacologic treatments like anti-VEGF in treating DR and diabetic macular edema (DME). A 20-year follow-up retrospective study in our center preliminarily demonstrated the long-term effectiveness of conventional laser photocoagulation. Conclusions: More clinical trials are required to confirm the clinical effectiveness of novel laser technologies. Better treatment protocols for the combination therapy may be detailed. Anti-VEGF treatment has better effects, especially for DME and in a short period. But in real-world conditions, given the long-term effectiveness and economic advantages of conventional laser treatment, it should be prioritized over anti-VEGF injection in certain situations.

Peripheral retinal lesions in diabetic retinopathy on ultra-widefield imaging

Peripheral retinal imaging plays a crucial role in the diagnosis, management, and prognosis of diabetic retinopathy (DR). Traditional fundus imaging techniques have limited coverage of the retina, resulting in missed peripheral lesions. The advent of ultra-widefield (UWF) imaging has revolutionized the assessment of the peripheral retina. UWF imaging modalities provide comprehensive visualization of the retina, enabling the detection of peripheral lesions without the need for mydriasis. Integration of UWF imaging with other modalities, including fluorescein angiography (FA), indocyanine green angiography, pseudocolor imaging, and fundus autofluorescence, further enhances our understanding of peripheral retinal lesions. UWF imaging has demonstrated improved detection of DR lesions and presumably more accurate management of DR compared to traditional fundus photography and dilated fundus examination. UWF-FA and UWF-optical coherence tomography angiography have emerged as valuable tools for assessing retinal and choroidal vascular abnormalities, nonperfusion areas, neovascularization, and microvascular abnormalities. The presence and increasing extent of predominantly peripheral lesions detected using UWF FA are associated with a higher risk of DR progression and proliferative DR. UWF imaging provides a comprehensive evaluation of DR severity, aiding in more accurate risk stratification and treatment decision-making. Overall, UWF imaging modalities have significantly advanced our understanding of peripheral retinal lesions in DR, facilitating early detection and targeted management for better visual outcomes.

Advances in targeted retinal photocoagulation in the treatment of diabetic retinopathy

AIM

Targeted retinal photocoagulation (TRP) is an emerging laser technology for retinal targeted therapy. TRP can specifically act on unperfused retinal capillaries and retinal intermediate ischemic areas, reduce damage to tissue perfusion areas and panretinal photocoagulation (PRP) complications or adverse events. In this regard, this review discusses the treatment options, efficacy, and latest progress of TRP for diabetic retinopathy (DR) based on randomized controlled trial (RCT), meta-analysis, case review, and other existing studies.

METHODS

In-depth research was conducted on articles about the proposal and development of TRP, its simple application in DR, and combined therapy. In order to review the new progress, application methods, effects, and prospects of TRP in the treatment of DR, the articles related to TRP in the databases of PubMed and Web Of Science since this century were comprehensively analyzed.

RESULTS

TRP is effective in treating DR and may become a substitute for PRP in the future. In addition, the treatment regimen of TRP combined with intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) drugs can also be used as a new therapeutic approach to expand the treatment regimen for the treatment of DR, and this combination therapy also has effects on other retinal vascular diseases.

CONCLUSIONS

With the advancement of technology, TRP has been continuously applied in clinical practice, and its potential benefits have opened up broad prospects for the treatment of DR. The combination therapy of TRP and anti-VEGF is expected to become a new option for patients with DR an retinal diseases.

Conventional and Pattern Scanning Pan-Retinal Photocoagulation Laser in Diabetic Patients' Visual Field

Introduction: In this study, we aimed to compare visual field defects in two different laser methods, namely conventional pan-retinal photocoagulation (PRP) and pattern scanning PRP, in patients with either proliferative diabetic or very severe non-proliferative diabetic retinopathy. Methods: This study was a randomized, single-blind, prospective clinical trial. Twenty patients with either proliferative or very severe non-proliferative diabetic retinopathy were enrolled in this study. Notably, only those patients with the same severity scores in both eyes were included. One eye underwent the conventional PRP laser and another eye underwent the pattern scanning PRP laser simultaneously. Swedish interactive threshold algorithms (SITA) standard perimetry was performed at baseline and one month after the treatment, and visual field defects were evaluated. Results: The pattern standard deviation (PSD) significantly increased in both the pattern and conventional PRP laser groups after one month. The change of the PSD at baseline and after the treatment was not significant between the groups. The mean deviation (MD) level significantly decreased in the conventional group after one month. The change in the MD level at baseline and after the treatment was not significant between the pattern and conventional groups. The change in the mean best corrected visual acuity (BCVA) between the groups was not significant. Conclusion: Changes in visual acuity and visual fields of the patients between the pattern and conventional PRP laser methods showed no significant difference; however, the pattern PRP method caused a smaller reduction in overall sensitivity in the patient's visual field.

Current status and future possibilities of retinal imaging in diabetic retinopathy care applicable to low- and medium-income countries

Diabetic retinopathy (DR) is a leading cause of blindness among adults and the numbers are projected to rise. There have been dramatic advances in the field of retinal imaging since the first fundus image was captured by Jackman and Webster in 1886. The currently available imaging modalities in the management of DR include fundus photography, fluorescein angiography, autofluorescence imaging, optical coherence tomography, optical coherence tomography angiography, and near-infrared reflectance imaging. These images are obtained using traditional fundus cameras, widefield fundus cameras, handheld fundus cameras, or smartphone-based fundus cameras. Fluorescence lifetime ophthalmoscopy, adaptive optics, multispectral and hyperspectral imaging, and multicolor imaging are the evolving technologies which are being researched for their potential applications in DR. Telemedicine has gained popularity in recent years as remote screening of DR has been made possible. Retinal imaging technologies integrated with artificial intelligence/deep-learning algorithms will likely be the way forward in the screening and grading of DR. We provide an overview of the current and upcoming imaging modalities which are relevant to the management of DR.

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.

The Role of Ultra-Widefield Fundus Imaging and Fluorescein Angiography in Diagnosis and Treatment of Diabetic Retinopathy

PURPOSE OF REVIEW

Early detection and treatment are important for preventing vision loss from diabetic retinopathy. Historically, the gold standard for grading diabetic retinopathy has been based on 7-field 30-degree color fundus photographs that capture roughly the central third of the retina. Our aim was to review recent literature on the role of ultra-widefield (allowing capture of up to 82% of the retina in one frame) fundus imaging in screening, prognostication, and treatment of diabetic retinopathy.

RECENT FINDINGS

Ultra-widefield fundus imaging can capture peripheral retinal lesions outside the traditional 7-field photographs that may correlate with increased risk of diabetic retinopathy progression. The speed and ability to image through undilated pupils make ultra-widefield imaging attractive for tele-ophthalmology screening. Ultra-widefield fluorescein angiography may help guide targeted laser treatment in eyes with proliferative diabetic retinopathy. Ultra-widefield imaging has potential to help shape new diabetic retinopathy screening, staging, and treatment protocols.

Effect of pattern scanning laser on macular thickness in diabetic retinopathy

Purpose:

This study investigates the effect of pattern scanning laser (PASCAL) panretinal photocoagulation (PRP) on central macular thickness (CMT) and visual acuity (VA) in patients with proliferative diabetic retinopathy (PDR).

Methods:

This retrospective non-randomized comparative case series included 262 eyes (163 with macular edema) of 177 patients with PDR. Treatment was PRP alone (137), PRP + anti-vascular endothelial growth factor (VEGF) (69), PRP + focal laser (28), or all three (89). CMT and central macular volume 3 and 6 mm from fovea were analyzed before and 1, 3, and 6 months after PRP. Spot number was plotted against CMT, and linear regression analysis was performed.

Results:

For each treatment group and time point, there was a non-significant relationship between spot number and CMT. In eyes receiving all three treatment modalities, a significant negative relationship was found between spot number and 3-mm volume at 6 months (p = 0.04) and 6-mm volume at 1 month (p = 0.002) and 6 months (p = 0.011). There was no significant change in VA in any treatment group at the 6-month time point.

Conclusion:

PASCAL PRP ± focal laser or anti-VEGF was not associated with increased development of macular edema or change in VA. PASCAL PRP with focal laser and anti-VEGF may result in a decrease in macular edema.

Proliferative diabetic retinopathy treated with intravitreal ranibizumab and photocoagulation directed at ischemic retinal areas-A randomized study

PURPOSE

To compare ETDRS panretinal laser photocoagulation (PRP) combined with intravitreal injection of ranibizumab (IVR) and photocoagulation targeted to ischemic retina (PIR) combined with IVR in patients with proliferative diabetic retinopathy (PDR).

METHODS

PDR patients were randomly assigned to treatment with either PRP + IVR or PIR + IVR. ETRDS Best-corrected visual acuity (BCVA) and central subfield thickness (CSFT) measured on optic-coherence tomography images (OCT-Heidelberg Spectralis) were recorded at baseline and every 4 weeks for one year. Fluorescein leakage area (FLA) from active new vessels was measured every 12 weeks. Full-field ERG was recorded by means of DTL electrodes, following ISCEV standard recommendations, at baseline and after 3 months.

RESULTS

Twenty-eight eyes completed the study period. At baseline, mean ± SE BCVA (logMAR) was 0.44 ± 0.07 and 0.37 ± 0.08 (P = 0.5030); CSFT (μm) was 324.0 ± 20.4 and 330.1 ± 22.1 (P = 0.8417); and FLA (mm²) was 16.10 ± 4.42 and 9.97 ± 1.83 (P = 0.2114) for PRP + IVR and PIR + IVR groups, respectively. There were no relevant changes on BCVA or CSFT, but a significant reduction for FLA was observed at all visits compared to baseline for both groups, with no differences between groups. ERG showed at baseline reduced dark-adapted amplitudes, and these changes were also significantly amplified after laser treatment. ROD b-wave amplitude was further reduced in 62 ± 6% for PRP + IVR and 59 ± 4% for group PIR + IVR, but with no between-groups significant difference (P = 0.9082).

CONCLUSIONS

PIR + IVR or PRP + IVR are comparable strategies regarding FLA control in PDR and led to similar retinal function impairment, based on ERG changes up to one-year follow-up.

TRIAL REGISTRATION NUMBER

NCT03904056, date of registration 02/11/2019, retrospectively registered.

Diabetic retinopathy and diabetic macular oedema pathways and management: UK Consensus Working Group

The management of diabetic retinopathy (DR) has evolved considerably over the past decade, with the availability of new technologies (diagnostic and therapeutic). As such, the existing Royal College of Ophthalmologists DR Guidelines (2013) are outdated, and to the best of our knowledge are not under revision at present. Furthermore, there are no other UK guidelines covering all available treatments, and there seems to be significant variation around the UK in the management of diabetic macular oedema (DMO). This manuscript provides a summary of reviews the pathogenesis of DR and DMO, including role of vascular endothelial growth factor (VEGF) and non-VEGF cytokines, clinical grading/classification of DMO vis a vis current terminology (of centre-involving [CI-DMO], or non-centre involving [nCI-DMO], systemic risks and their management). The excellent UK DR Screening (DRS) service has continued to evolve and remains world-leading. However, challenges remain, as there are significant variations in equipment used, and reproducible standards of DMO screening nationally. The interphase between DRS and the hospital eye service can only be strengthened with further improvements. The role of modern technology including optical coherence tomography (OCT) and wide-field imaging, and working practices including virtual clinics and their potential in increasing clinic capacity and improving patient experiences and outcomes are discussed. Similarly, potential roles of home monitoring in diabetic eyes in the future are explored. The role of pharmacological (intravitreal injections [IVT] of anti-VEGFs and steroids) and laser therapies are summarised. Generally, IVT anti-VEGF are offered as first line pharmacologic therapy. As requirements of diabetic patients in particular patient groups may vary, including pregnant women, children, and persons with learning difficulties, it is important that DR management is personalised in such particular patient groups. First choice therapy needs to be individualised in these cases and may be intravitreal steroids rather than the standard choice of anti-VEGF agents. Some of these, but not all, are discussed in this document.

Clinical Characteristics of Eyes Showing a Discrete Margin of Different Retinal Reflectivity

BACKGROUND AND OBJECTIVE

To evaluate the clinical characteristics of discrete margins of different retinal reflectivity (DMDRR) in ultra-widefield fundus photography.

PATIENTS AND METHODS

This DMDRR comprises a discrete border, with differing patterns of reflectivity on either side. Spectral-domain optical coherence tomography was performed on both the macula and the margin. The incidences of epiretinal membrane (ERM) and peripheral retinal pathologies of patients with a DMDRR (n = 36) were compared with a control group (n = 41).

RESULTS

An ellipsoid zone (EZ) defect at the DMDRR was detected in 34 eyes (92.2%), and vitreous traction was detected in 20 eyes (55.6%). A significantly higher proportion of eyes in the DMDRR group had an ERM, retinal hole, and cystic retinal tuft compared with the control group (P = .022, P = .010, and P < .001, respectively).

CONCLUSIONS

The DMDRR indicates EZ disruption that may originate from vitreous traction. Meticulous observation for vitreoretinal interface diseases is mandatory for these patients. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:273-280.].

Ultra-wide field retinal imaging: A wider clinical perspective

The peripheral retina is affected in a variety of retinal disorders. Traditional fundus cameras capture only a part of the fundus even when montaging techniques are used. Ultra-wide field imaging enables us to delve into the retinal periphery in greater detail. It not only facilitates assessing color images of the fundus, but also fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and red and green free images. In this review, a literature search using the keywords "ultra-widefield imaging", "widefield imaging", and "peripheral retinal imaging" in English and non-English languages was done and the relevant articles were included. Ultra-wide field imaging has made new observations in the normal population as well as in eyes with retinal disorders including vascular diseases, degenerative diseases, uveitis, age-related macular degeneration, retinal and choroidal tumors and hereditary retinal dystrophies. This review aims to describe the utility of ultra-wide field imaging in various retinal disorders.

Swept-source optical coherence tomography angiography vitreo-retinal segmentation in proliferative diabetic retinopathy

PURPOSE

To identify a new cortical vitreous segmentation protocol for non invasive standardised investigation of Neovascularisation (NV) with detection of regression of NV activity in Proliferative Diabetic Retinopathy (PDR).

DESIGN

Retrospective study.

PARTICIPANTS

One hundred and eighty-six eyes of 93 consecutive diabetic patients (mean age: 52.6 ± 11.0 years) imaged using Topcon Triton^® Swept-Source Optical Coherence Tomography Angiography (SS-OCTA) from June 2015 to January 2017.

METHODS

Scans were performed through the macula, optic disc and areas of possible NV in mid-peripheral retina using 6 × 6 mm and/or 9 × 9 mm raster-patterns in three segmentation protocols: Vitreo-Retinal (VRS), Outer-Vitreous (OVS) and Core-Vitreous Segmentation (CVS). Any suspicion of PDR was confirmed in all patients by Heidelberg^® Widefield-Fundus-Fluorescein-Angiography (WF-FFA) and/or Optos^® Ultra-WF-FFA (UWF-FFA). Inter-observer reproducibility of NV diagnosis and agreement between SS-OCTA and UWF-FFA were assessed. Primary outcome was the identification of an effective and reproducible segmentation protocol. Secondary outcome was the identification of NV regression after treatment.

RESULTS

Sensitivity-specificity reached, respectively, the value of 100 to 100 in detecting NVD, and 96.6 to 100 in detecting NVE in compared areas. SS-OCTA was able to confirm absence of blood flow within the residual NV plexus when using VRS protocol in 30 eyes in which regression of NV with absence of leakage was documented on FFA.

CONCLUSION

Three segmentation protocols (VRS, OVS and CVS) with different but complementary characteristics, allowed a reproducible and standardised investigation of NVD and NVE. The proposed new SS-OCTA cortical vitreous segmentation protocols may be of value when identifying and assessing NV-activity (VRS, OVS and CVS) or NV-regression (VRS) in PDR and therefore, response to therapy.

VASCULAR ABNORMALITIES IN DIABETIC RETINOPATHY ASSESSED WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY WIDEFIELD IMAGING

PURPOSE

To detect vascular abnormalities in diabetic retinopathy using swept-source optical coherence tomography angiography (SS-OCTA) widefield images, and to compare the findings with color fundus photographs (CFPs) using Early Treatment Diabetic Retinopathy Study severity grading.

METHODS

3 mm × 3 mm and 12 mm × 12 mm scans were acquired to cover 70° to 80° of the posterior pole using a 100-kHz SS-OCTA instrument. Two masked graders assessed the presence of vascular abnormalities on SS-OCTA and the Early Treatment Diabetic Retinopathy Study level on CFP. The grading results were then compared.

RESULTS

A total of 120 diabetic eyes (60 patients) were imaged with the SS-OCTA instrument. Cohort 1 (91 eyes; SS-OCTA grading only) showed microaneurysms in 91% (n = 83), intraretinal microvascular abnormalities in 79% (n = 72), and neovascularization in 21% (n = 19) of cases. Cohort 2 (52 eyes; CFP grading compared with SS-OCTA) showed microaneurysms on CFP in 90% (n = 47) and on SS-OCTA in 96% (n = 50) of cases. Agreement in intraretinal microvascular abnormality detection was fair (k = 0.2). Swept-source optical coherence tomography angiography detected 50% of intraretinal microvascular abnormality cases (n = 26), which were missed on CFP. Agreement in detecting neovascularization was moderate (k = 0.5).

CONCLUSION

Agreement in detection of diabetic retinopathy features on CFP and SS-OCTA varies depending on the vascular changes examined. Swept-source optical coherence tomography angiography shows a higher detection rate of intraretinal microvascular abnormalities (P = 0.039), compared with Early Treatment Diabetic Retinopathy Study grading.

Ultra-widefield retinal imaging: an update on recent advances

The development of ultra-widefield retinal imaging has accelerated our understanding of common retinal diseases. As we continue to validate the diagnostic and prognostic significance of pathology in the retinal periphery, the ability to visualize and evaluate these features in an efficient and patient-friendly manner will become more important. Current interest in ultra-widefield imaging includes the development of potential biomarkers of disease progression and indicators of preclinical disease development. This article reviews the current ultra-widefield imaging systems and recent advances in their applications to clinical practice with a focus on diabetic retinopathy, retinal vein occlusion, uveitis, and pediatric retina.

Wide-field imaging in proliferative diabetic retinopathy

Background

Diabetic retinopathy (DR) is one of the leading causes of vision loss worldwide. For decades, 7-field 30-degree fundus imaging has been the gold standard for DR classification. The aim of this review article is to discuss how the advent of ultra-wide-field (UWF) fundus imaging has changed the management of proliferative diabetic retinopathy (PDR).

Main body

Current data suggests that UWF imaging, as compared to conventional Early Treatment Diabetic Retinopathy Study (ETDRS) fields, detects additional and more extensive PDR pathologies. DR lesions, captured by UWF imaging outside of ETDRS fields, likely carry prognostication value.

Conclusion

UWF imaging represents a major advancement in the detection and management of DR. It remains unclear whether, when and how patients, with PDR changes only peripheral to standard ETDRS fields, should be treated. A larger, prospective, randomized clinical trial is also needed to compare the efficacy of UWF image-guided targeted laser photocoagulation with that of conventional panretinal photocoagulation.

Comparison of ranibizumab alone versus ranibizumab with targeted retinal laser for branch retinal vein occlusion with macular edema

Purpose:

To determine the effect of ultra-widefield fluorescein angiography (UWFFA)-guided targeted retinal photocoagulation (TRP) in branch retinal vein occlusion (BRVO) with macular edema after intravitreal Ranibizumab (RBZ).

Methods:

33 eyes of 32 treatment naïve patients diagnosed as BRVO with macular edema were prospectively randomized to 0.5 mg Ranibizumab only (RBZ group) (n = 17) or Ranibizumab with UWFFA-guided laser (RBZ + TRP group) (n = 16). Both groups received three injections at monthly intervals and PRN henceforth. RBZ + TRP group additionally underwent UWFFA-guided TRP of peripheral capillary nonperfusion areas 1 week post injection. Outcome measures included improvement in visual acuity, central subfoveal thickness (CST), and the number of injections required with a minimum follow-up of 9 months.

Results:

Both groups showed significant improvement in mean BCVA (25.7 ± 8.19 letters, P < 0.001 vs. 23.38 ± 7.56 letters, P < 0.001; in RBZ and RBZ + TRP group, respectively) and reduction in mean central subfoveal thickness (379.12 ± 242.7 μm, P < 0.001 vs. 253.75 ± 137.9 μm, P < 0.001 in RBZ and RBZ + TRP group, respectively) at 9 months. The number of injections in the RBZ group (5.76 ± 1.3) was significantly greater than RBZ + TRP (4.06 ± 0.99) (P < 0.001). Both groups had significant improvement in contrast sensitivity and mean deviation on visual fields; however, the difference between the groups was not significant (P = 0.62 and P = 0.79, respectively).

Conclusion:

UWFFA-guided TRP reduced the number of injections of Ranibizumab in patients having BRVO with macular edema, while maintaining similar benefits in the improvement of BCVA, central subfoveal thickness without deleterious effect on the visual field, and contrast sensitivity.

New imaging systems in diabetic retinopathy

Various imaging modalities are of significant utility in the screening, grading, treatment, and follow-up of the different stages of diabetic retinopathy (DR) and diabetic macular edema. Color stereographic photography, fluorescein angiography, and optical coherence tomography (OCT) have been the gold standard for DR imaging for years. Besides these tools, newer technologies are gaining validation and popularity, such as fundus autofluorescence and OCT angiography. Furthermore, widefield retinography and ultra-widefield retinography have been introduced for a more comprehensive evaluation of the medium-far and very-far retinal peripheries, which is crucial for the assessment of the diverse manifestations of the disease. The aim of this review is to illustrate the recent advancements of the imaging systems for diagnosing DR, with a focus on the newest and noninvasive diagnostic tools.

Comparison of Digital Widefield Retinal Imaging With Indirect Ophthalmoscopy in Pediatric Patients

BACKGROUND AND OBJECTIVE

Approximately 16,000 children in the United States lose vision each year because of retinal disease. The authors compare digital ultra-widefield (UWF) photography to indirect ophthalmoscopy in children.

PATIENTS AND METHODS

Prospective, single-center study of patients ages 3 to 17 years. Retinal area during indirect ophthalmoscopy was compared with retinal area in digital UWF fundus photographs. Image quality was graded. A survey to assess the usefulness of the retinal image was obtained.

RESULTS

The retinal area (mean ± standard deviation, mm²) evaluated with indirect ophthalmoscopy was 413 ± 194 mm², compared with 652 ± 117 mm² with widefield photography (P < .001). The difference was largest in children younger than 14. Image quality was significantly associated with patient cooperation.

CONCLUSIONS

High-quality UWF photographs evaluate more peripheral retina than the in-office dilated funduscopic exam in children under 14. Photography assisted with family counseling in 17% of patients and the avoidance of examination under anesthesia in 2% of patients. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:580-585.].

The impact of spot size, spacing, pattern, duration and intensity of burns on the photocoagulation index in a geometric simulation of pan-retinal laser photocoagulation

PURPOSE

To evaluate the impact of spot size, spacing, pattern, duration and intensity of burns on the photocoagulation index, using a geometric simulation of pan-retinal laser photocoagulation.

METHODS

Simulations of full-scattered pan-retinal laser photocoagulation were performed on a retinal map, using a geometry-based method. Simulations consisted of 300-, 400- or 500-μm diameter equidistant spots on the retina with 1.0-spot width spacing, as well as 400-μm diameter spots on the retina in an equidistant pattern or grid pattern, with 1.0-, 0.75-, 0.50-, 0.25- or 0-spot width spacing. For each simulation, we calculated the ratio of the total photocoagulated retinal area to the whole retina, termed the photocoagulation index. We recalculated the photocoagulation indexes using the expansion ratios of photocoagulated lesions by different duration and intensity of burns from a previous study.

RESULTS

The photocoagulation indexes of the simulated pan-retinal laser photocoagulation with 300-, 400- and 500-μm diameter spots were 20.8%, 20.6% and 21.0%, respectively. The photocoagulation indexes of the 1.0-, 0.75-, 0.50-, 0.25- and 0-spot width spacing configurations of pan-retinal laser photocoagulation burns for the equidistant pattern were 20.6%, 27.1%, 36.7%, 53.2% and 83.1%, respectively, and those for the grid pattern were 17.9%, 23.5%, 31.8%, 46.1% and 72.0%, respectively. The photocoagulation indexes obtained with the equidistant and grid patterns changed (range, 1.7-84.7% and 1.5-73.4%, respectively) when the duration or burn intensity of the pan-retinal photocoagulation was changed.

CONCLUSION

This geometric simulation method could evaluate the impact of a range of conditions on the photocoagulation index.

Multimodal imaging of diabetic retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy is the most common microvascular complication of diabetes mellitus and a leading cause of blindness throughout the world. Ocular imaging continues to play a vital role in the diagnosis, management and monitoring of diabetic retinopathy. Major technological advancements in imaging over the past decade have improved our understanding and knowledge of diabetic retinopathy and therefore a multimodal approach to imaging has become the standard of care.

RECENT FINDINGS

Updates to traditional technologies such as digital fundus photography along with recent advancements in optical coherence tomography (OCT) and OCT angiography (OCTA) have provided clinicians with new information and improved efficiency.

SUMMARY

In this review, we describe the benefits and clinical applications of several imaging techniques in diabetic retinopathy including color photography, fluorescein angiography, OCT, OCTA and adaptive optics. Understanding the indications and limitations of each technology allows clinicians to gain the most information from each modality and thereby optimize patient care.

The clinical relevance of visualising the peripheral retina

Recent developments in imaging technologies now allow the documentation, qualitative and quantitative evaluation of peripheral retinal lesions. As wide field retinal imaging, capturing both the central and peripheral retina up to 200° eccentricity, is becoming readily available the question is: what is it that we gain by imaging the periphery? Based on accumulating evidence it is clear that findings in the periphery do not always associate to those observed in the posterior pole. However, the newly acquired information may provide useful clues to previously unrecognised disease features and may facilitate more accurate disease prognostication. In this review, we explore the anatomy and physiology of the peripheral retina, focusing on how it differs from the posterior pole, recount the history of peripheral retinal imaging, describe various peripheral retinal lesions and evaluate the overall relevance of peripheral retinal findings to different diseases.

Precise Measurement of Retinal Vascular Bed Area and Density on Ultra-wide Fluorescein Angiography in Normal Subjects

PURPOSE

To characterize and quantify the total retinal vascular bed area (RVBA) and vascular density (VD) in normal eyes using stereographically corrected ultra-wide-field (UWF) fluorescein angiography (FA).

DESIGN

Cross-sectional study.

METHODS

Fifty-nine eyes of 31 normal subjects with no evidence of ocular disease underwent FA using the Optos 200Tx (Optos plc, Dunfermline, United Kingdom). Central and peripheral-steered FA images were montaged and stereographically projected. The early-phase FA was used to extract the retinal vasculature as a binary mask. Two independent, masked reading center-certified graders delineated the peripheral edge of the total retinal area (TRA) on a middle-phase frame. The RVBA and TRA were computed automatically in mm² using software provided by the manufacturer. The VD was calculated by dividing RVBA by TRA.

RESULTS

The mean RVBA was 42.3 ± 14.8 mm² for the entire retina, with no difference between male and female subjects (P = .439) or between right and left eyes (P = .407). The mean VD was 4.3% ± 1.4% for the entire retina, with no difference based on sex (P = .629) or laterality (P = .426). A negative correlation was observed between age and both RVBA and VD (RVBA: R = -0.6, P < .001; VD: R = -0.52, P < .001). Pairwise comparisons showed that subjects aged >65 years had smaller RVBA and VD than those younger than 50 years for the entire retina and in all quadrants.

CONCLUSIONS

RVBA and VD can be extracted from UWF FA images using automated processing techniques and may provide a reliable alternative to measures such as nonperfusion area.

Electroretinogram evaluation for the treatment of proliferative diabetic retinopathy by short-pulse pattern scanning laser panretinal photocoagulation

Panretinal photocoagulation (PRP) is a standard method for proliferative diabetic retinopathy (PDR) treatment. However, conventional PRP usually significantly damages the retinal structure and vision. Retinal pattern scanning laser (PASCAL) photocoagulation has emerged as a new technique with fewer complications for the treatment of retinal disorders. This study compares the therapeutic effects of short-pulse PASCAL to conventional single-spot PRP for PDR. Fifty-two PDR patients (104 eyes) were randomly assigned into a short-pulse PASCAL-PRP treatment (SP) group and a conventional PRP treatment (TP) group. The best corrected visual acuity (BCVA) and full-field flash electroretinogram (ERG) data were evaluated before and after the two treatments. The BCVA data between before and after the PRP treatments did not show any significant difference. After the PRP treatment, the b-wave amplitude (b-A) in the dark-adapted 3.0 ERG (p = 0.0005) and the amplitude in the light-adapted 3.0 flicker ERG (p = 0.009) were significantly higher in the SP group compared with that of the TP group. In addition, after the PRP treatment, the a-wave implicit time (a-T) of light-adapted 3.0 ERG prolonged significantly in the TP group compared to the SP group. Compared with the parameters before the treatments, the a-A and b-A under dark-adapted 3.0 ERG and the b-A under the light-adapted 3.0 ERG in both TP and SP groups after the treatments decreased significantly (p < 0.05). Short-pulse PASCAL-PRP significantly attenuated partial vision damage compared to conventional PRP, although it still caused limited retinal injury and mild reduction in retinal function. These findings suggest that short-pulse PASCAL-PRP is a promising technique for PDR treatment.

Bullous Exudative Retinal Detachment after Retinal Pattern Scan Laser Photocoagulation in Diabetic Retinopathy

Laser retinal photocoagulation is the gold standard treatment for diabetic retinopathy. We describe 3 cases in which bullous exudative retinal detachment (ERD) developed after pattern scan laser photocoagulation (PASCAL) in diabetic retinopathy. ERD spontaneously resolved in all 3 cases with various visual courses. This case series highlights 2 key points: first, ERD can occur regardless of gender, age, glycemic control, or vitreous status and despite a moderate number of laser shots, even with PASCAL; second, ERD in nonvitrectomized eyes may cause irreversible visual loss, even if the ERD resolves within 1 month.

Foveal Microstructure Analysis in Eyes with Diabetic Macular Edema Treated with Vitrectomy

INTRODUCTION

The purpose of this study was to evaluate baseline and postoperative factors affecting outcomes after vitrectomy for diabetic macular edema (DME) using optical coherence tomography (OCT).

METHODS

Vitrectomy combined with inner limiting membrane (ILM) peeling and additional laser photocoagulation therapy was performed on 36 eyes of 30 DME patients. Evaluations included the logarithm of the minimal angle of resolution (logMAR), best-corrected visual acuity (BCVA) and OCT parameters at baseline and 1, 3, 6, and 12 months postoperatively. Correlations between OCT parameters and BCVA were assessed at each follow-up visit. Correlations among postoperative BCVA and preoperative BCVA, foveal macular thickness (FMT), outer foveal thickness (OFT), and photoreceptor outer segment (PROS) length were evaluated using multiple regression analysis.

RESULTS

BCVA significantly improved from 0.50 ± 0.25 to 0.34 ± 0.26 at 12 months postoperatively (P < 0.001). Mean FMT improved significantly from 526.4 ± 120.4 to 384.6 ± 120.5 at 1 month, 325.2 ± 100.3 at 3 months, 304.1 ± 102.5 at 6 months and 274.2 ± 86.6 μm at 12 months postoperatively (P < 0.001, respectively). OFT 1 month after surgery was significantly decreased 46.5 ± 14.7-40.2 ± 14.4 μm (P = 0.017), although at 3, 6, and 12 months it did not differ from the baseline value. PROS length 1 month after surgery significantly decreased from 31.7 ± 6.9-28.8 ± 6.8 μm (P = 0.015) and that at 3 months and 6 months recovered to the baseline value. PROS length 12 months after surgery was significantly increased to 34.3 ± 7.2 μm from baseline (P = 0.023). Mean FMT was not correlated with BCVA at any time point. Mean OFT and PROS length at 3, 6, and 12 months were correlated with BCVA. In multiple regression analysis, PROS length had the greatest effect on VA 12 months postoperatively (P = 0.0262, standard regression coefficient = -0.366).

CONCLUSION

Current surgery helps DME patients to maintain VA and foveal structures. The results suggest that PROS length predicts visual outcome in DME patients following vitrectomy with ILM peeling and additional laser photocoagulation.

Ultra-wide-field imaging in diabetic retinopathy

Since 1991, 7-field images captured with 30-50 degree cameras in the Early Treatment Diabetic Retinopathy Study were the gold standard for fundus imaging to study diabetic retinopathy. Ultra-wide-field images cover significantly more area (up to 82%) of the fundus and with ocular steering can in many cases image 100% of the fundus ("panretinal"). Recent advances in image analysis of ultra-wide-field imaging allow for precise measurements of the peripheral retinal lesions. There is a growing consensus in the literature that ultra-wide-field imaging improves detection of peripheral lesions in diabetic retinopathy and leads to more accurate classification of the disease. There is discordance among studies, however, on the correlation between peripheral diabetic lesions and diabetic macular edema and optimal management strategies to treat diabetic retinopathy.

Ultra-wide-field fluorescein angiography in diabetic retinopathy: a narrative review

Fluorescein angiography (FA) is a useful examination in patients suffering from diabetic retinopathy (DR). Traditional angiograms explore 30°–50° of the retina at once; however, visualization of peripheral retina is fundamental in order to assess nonperfused areas, vascular leakage, microvascular abnormalities, and neovascularizations. In order to expand the field of view, wide-field and ultra-wide-field imaging has been developed allowing to image up to 200° of retinal surface in one single shot. The aim of this narrative review was to provide an overview of the role of the most recent technique of ultra-wide-field fluorescein angiography in DR.

Extended targeted retinal photocoagulation versus conventional pan-retinal photocoagulation for proliferative diabetic retinopathy in a randomized clinical trial

PURPOSE

To determine the clinical efficacy of extended targeted retinal photocoagulation (ETRP) compared to conventional panretinal photocoagulation (CPRP) in proliferative diabetic retinopathy (PDR).

METHODS

In a single-masked randomized clinical trial, 270 eyes of 234 patients with naïve early or high-risk PDR were randomly assigned to receive either CPRP or ETRP (135 eyes, each treatment arm). Best-corrected visual acuity (BCVA) measurement, fundus examination, wide-field fluorescein angiography (WFFA) and optical coherence tomography were carried out before and 3 months after retinal photocoagulation. Primary outcome was early PDR regression, specified as reduction in retinal neovascularization based on WFFA at 3 months. Secondary outcomes were BCVA and central macular thickness (CMT) changes.

RESULTS

There were significantly more high-risk PDR eyes in ETRP group compared to CPRP (109 and 94 eyes, respectively, P = 0.04). Early PDR regression occurred in 71.9 and 64.4% of eyes in the ETRP and CPRP groups, respectively (P = 0.19). The mean number of applied laser spots in the ETRP was significantly fewer than CPRP (1202 vs. 1360, respectively, P < 0.001). Mean BCVA at baseline and 3 months post-laser were 0.37 ± 0.26 and 0.47 ± 0.19 logMAR in the ETRP arm, respectively. In the CPRP arm these values were 0.40 ± 0.27 and 0.47 ± 0.24 logMAR, respectively. Although mean BCVA decreased significantly in both treatment arms (ETRP P < 0.001, CPRP P = 0.009), the difference was not significant between arms (P = 0.68). CMT increased significantly in both groups (ETRP 41.08 μm, P < 0.001, CPRP 33.31 μm, P < 0.001). Nevertheless, the difference between the groups was not significant (P = 0.26).

CONCLUSIONS

ETRP with fewer number of laser spots may be an appropriate alternative to CPRP in PDR regression at least through 3 months.

CLINICAL TRIAL

GOV REGISTRATION NUMBER

NCT01232179.

Comparison of Efficacy and Side Effects of Multispot Lasers and Conventional Lasers for Diabetic Retinopathy Treatment

Panretinal photocoagulation (PRP) is a standard treatment for proliferative diabetic retinopathy. Conventional laser (CL) therapy is performed in one or more sessions in single spot mode. Visual disabilities have been reported after treatment with CL, including central vision loss due to macular edema and peripheral visual field loss resulting from extensive inner retinal scarring. Multispot laser (MSL) photocoagulation has recently been introduced to clinical practice. Studies comparing PRP conducted with MSL and CL have reported that MSLs resulted in less retinal tissue damage and pain, and greater patient comfort compared to CL. The aim of this review was to compare the efficacy and side effects of MSLs and CLs for diabetic retinopathy treatment.

Advances in retinal imaging for diabetic retinopathy and diabetic macular edema

Diabetic retinopathy and diabetic macular edema (DME) are leading causes of blindness throughout the world, and cause significant visual morbidity. Ocular imaging has played a significant role in the management of diabetic eye disease, and the advent of advanced imaging modalities will be of great value as our understanding of diabetic eye diseases increase, and the management options become increasingly varied and complex. Color fundus photography has established roles in screening for diabetic eye disease, early detection of progression, and monitoring of treatment response. Fluorescein angiography (FA) detects areas of capillary nonperfusion, as well as leakage from both microaneurysms and neovascularization. Recent advances in retinal imaging modalities complement traditional fundus photography and provide invaluable new information for clinicians. Ultra-widefield imaging, which can be used to produce both color fundus photographs and FAs, now allows unprecedented views of the posterior pole. The pathologies that are detected in the periphery of the retina have the potential to change the grading of disease severity, and may be of prognostic significance to disease progression. Studies have shown that peripheral ischemia may be related to the presence and severity of DME. Optical coherence tomography (OCT) provides structural detail of the retina, and the quantitative and qualitative features are useful in the monitoring of diabetic eye disease. A relatively recent innovation, OCT angiography, produces images of the fine blood vessels at the macula and optic disc, without the need for contrast agents. This paper will review the roles of each of these imaging modalities for diabetic eye disease.

Update on wide- and ultra-widefield retinal imaging

The peripheral retina is the site of pathology in many ocular diseases and ultra-widefield (UWF) imaging is one of the new technologies available to ophthalmologists to manage some of these diseases. Currently, there are several imaging systems used in practice for the purpose of diagnostic, monitoring disease progression or response to therapy, and telemedicine. These include modalities for both adults and pediatric patients. The current systems are capable of producing wide- and UWF color fundus photographs, fluorescein and indocyanine green angiograms, and autofluorescence images. Using this technology, important clinical observations have been made in diseases such as diabetic retinopathy, uveitides, retinal vascular occlusions and tumors, intraocular tumors, retinopathy of prematurity, and age-related macular degeneration. Widefield imaging offers excellent postoperative documentation of retinal detachment surgery. New applications will soon be available to integrate this technology into large volume routine clinical practice.

A Computational Model of Peripheral Photocoagulation for the Prevention of Progressive Diabetic Capillary Occlusion

We developed a computational model of the propagation of retinal ischemia in diabetic retinopathy and analyzed the consequences of various patterns and sizes of burns in peripheral retinal photocoagulation. The model addresses retinal ischemia as a phenomenon of adverse local feedback in which once a capillary is occluded there is an elevated probability of occlusion of adjacent capillaries resulting in enlarging areas of retinal ischemia as is commonly seen clinically. Retinal burns of different sizes and patterns, treated as local oxygen sources, are predicted to have different effects on the propagation of retinal ischemia. The patterns of retinal burns are optimized with regard to minimization of the sum of the photocoagulated retina and computer predicted ischemic retina. Our simulations show that certain patterns of retinal burns are effective at preventing the spatial spread of ischemia by creating oxygenated boundaries across which the ischemia does not propagate. This model makes no statement about current PRP treatment of avascular peripheral retina and notes that the usual spot sizes used in PRP will not prevent ischemic propagation in still vascularized retinal areas. The model seems to show that a properly patterned laser treatment of still vascularized peripheral retina may be able to prevent or at least constrain the propagation of diabetic retinal ischemia in those retinal areas with intact capillaries.

ULTRA-WIDEFIELD FUNDUS IMAGING: A Review of Clinical Applications and Future Trends

PURPOSE

To review the basic principles of ultra-widefield fundus imaging and discuss its clinical utility for a variety of retinal and choroidal disorders.

METHODS

A systematic review of the PubMed database was performed using the search terms Optos, optomap, panoramic, ultra-widefield, wide-angle, and ellipsoid mirror. This yielded 158 publications of which 128 were selected based on content and relevance.

RESULTS

A total of 128 articles pertaining to ultra-widefield imaging were cited in this review.

CONCLUSION

Optos ultra-widefield imaging has become an essential tool for the identification of peripheral retinal and vascular pathology. The high resolution and multimodal capabilities of this device are also providing new insights into a variety of disorders, even those that primarily involve the posterior pole. Although the presence of artifact and the need for clinical validation are significant hurdles to more widespread use, ultra-widefield is evolving to become the standard-of-care imaging modality for many diseases and is finding new clinical and research applications such as for screening and telemedicine.

Advances in retinal imaging modalities: Challenges and opportunities

Imaging in ophthalmology is playing an increasingly important role not only in screening, but also in monitoring and assessing response to treatment in an objective manner. Technical advances in various modes of imaging acquisition provide more detailed images. These can be combined and reviewed on one screen in the place of acquisition or sent for a remote assessment. Moreover, the machines are more user-friendly, which reduces the need for highly skilled technicians. In this article the authors describe currently available and experimental ophthalmic imaging modalities and their impact on clinical practice.

Comparative study of combined bevacizumab/targeted photocoagulation vs bevacizumab alone for macular oedema in ischaemic branch retinal vein occlusions

PURPOSE

To investigate whether targeted retinal photocoagulation (TRP) of peripheral non-perfused areas (NPAs) could prevent the recurrence of macular oedema (ME) due to branch retinal vein occlusion (BRVO) after intravitreal bevacizumab injection (IVB).

METHODS

Eyes received 1.25 mg IVB only (IVB group) or combined with TRP (IVB + TRP group) of NPAs, more than 5 disc areas identified by fluorescein angiography in the patients with ME secondary to BRVO. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) determined by optical coherence tomography were measured every month for 6 months.

RESULTS

Thirty-eight patients were enrolled and randomized to IVB group (n = 19) and IVB + TRP group (n = 19). Both groups showed similar thinning in CRT at 1 week after IVB, IVB + TRP group maintained thinner retina at 2 (p = 0.0072) and 3 (p = 0.0086) months compared with IVB group in whom turned to thickened almost back to baseline at 3 months. The number of reinjections in IVB group (1.58 ± 0.69) was significantly greater (p = 0.0025) than that in IVB + TRP group (0.83 ± 0.62). BCVA significantly improved at 6 month in IVB + TRP group (p = 0.015), but not in IVB group.

CONCLUSION

TRP of NPAs reduced the amount of ME recurrence following IVB compared to IVB alone.

Ultra-wide-field imaging in diabetic retinopathy; an overview

PURPOSE

To present an overview on ultra-wide-field imaging in diabetic retinopathy.

METHODS

A comprehensive search of the pubmed database was performed using the search terms of "ultra-wide-field imaging", "ultra-wide-field fluorescein angiography" and "diabetic retinopathy". The relevant original articles were reviewed.

RESULTS

New advances in ultra-wide-field imaging allow for precise measurements of the peripheral retinal lesions. A consistent finding amongst these articles was that ultra-wide-field imaging improved detection of peripheral lesion. There was discordance among the studies, however, on the correlation between peripheral diabetic lesions and diabetic macular edema.

CONCLUSIONS

Visualization of the peripheral retina using ultra-wide-field imaging improves diagnosis and classification of diabetic retinopathy. Additional studies are needed to better define the association of peripheral diabetic lesions with diabetic macular edema.

Pan-retinal photocoagulation and other forms of laser treatment and drug therapies for non-proliferative diabetic retinopathy: systematic review and economic evaluation

BACKGROUND

Diabetic retinopathy is an important cause of visual loss. Laser photocoagulation preserves vision in diabetic retinopathy but is currently used at the stage of proliferative diabetic retinopathy (PDR).

OBJECTIVES

The primary aim was to assess the clinical effectiveness and cost-effectiveness of pan-retinal photocoagulation (PRP) given at the non-proliferative stage of diabetic retinopathy (NPDR) compared with waiting until the high-risk PDR (HR-PDR) stage was reached. There have been recent advances in laser photocoagulation techniques, and in the use of laser treatments combined with anti-vascular endothelial growth factor (VEGF) drugs or injected steroids. Our secondary questions were: (1) If PRP were to be used in NPDR, which form of laser treatment should be used? and (2) Is adjuvant therapy with intravitreal drugs clinically effective and cost-effective in PRP?

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) for efficacy but other designs also used.

DATA SOURCES

MEDLINE and EMBASE to February 2014, Web of Science.

REVIEW METHODS

Systematic review and economic modelling.

RESULTS

The Early Treatment Diabetic Retinopathy Study (ETDRS), published in 1991, was the only trial designed to determine the best time to initiate PRP. It randomised one eye of 3711 patients with mild-to-severe NPDR or early PDR to early photocoagulation, and the other to deferral of PRP until HR-PDR developed. The risk of severe visual loss after 5 years for eyes assigned to PRP for NPDR or early PDR compared with deferral of PRP was reduced by 23% (relative risk 0.77, 99% confidence interval 0.56 to 1.06). However, the ETDRS did not provide results separately for NPDR and early PDR. In economic modelling, the base case found that early PRP could be more effective and less costly than deferred PRP. Sensitivity analyses gave similar results, with early PRP continuing to dominate or having low incremental cost-effectiveness ratio. However, there are substantial uncertainties. For our secondary aims we found 12 trials of lasers in DR, with 982 patients in total, ranging from 40 to 150. Most were in PDR but five included some patients with severe NPDR. Three compared multi-spot pattern lasers against argon laser. RCTs comparing laser applied in a lighter manner (less-intensive burns) with conventional methods (more intense burns) reported little difference in efficacy but fewer adverse effects. One RCT suggested that selective laser treatment targeting only ischaemic areas was effective. Observational studies showed that the most important adverse effect of PRP was macular oedema (MO), which can cause visual impairment, usually temporary. Ten trials of laser and anti-VEGF or steroid drug combinations were consistent in reporting a reduction in risk of PRP-induced MO.

LIMITATION

The current evidence is insufficient to recommend PRP for severe NPDR.

CONCLUSIONS

There is, as yet, no convincing evidence that modern laser systems are more effective than the argon laser used in ETDRS, but they appear to have fewer adverse effects. We recommend a trial of PRP for severe NPDR and early PDR compared with deferring PRP till the HR-PDR stage. The trial would use modern laser technologies, and investigate the value adjuvant prophylactic anti-VEGF or steroid drugs.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005408.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Prediction of regression of retinal neovascularisation after panretinal photocoagulation for proliferative diabetic retinopathy

PURPOSE

The purpose of this study was to evaluate the regression of neovascularization elsewhere (NVE) after panretinal photocoagulation (PRP) based on its location in relation to the internal limiting membrane (ILM).

METHODS

Participants in this retrospective case series were 47 patients with active NVE within the vascular arcade. All patients were treated with PRP and followed up for at least 12 months. The time to regression of NVE based on its location relative to the ILM on spectral domain-optical coherence tomography (SD-OCT) was analyzed.

RESULTS

The proportion of eyes, showing regression of NVE at the end of follow-up period was 19/25 (76 %) in the "below ILM" group and 13/22 (59 %) in the "above ILM" group. The "below ILM" group was associated with a twofold enhanced regression of NVE in comparison to the "above ILM" group (HR = 2.13, p = 0.038).

CONCLUSIONS

Regression of NVE is determined by its location relative to the ILM. Patients with "below ILM" NVE were found to show a twofold increased regression rate in comparison with the "above ILM" group, while the proportion of eyes showing regression of NVE at the end of the follow-up period was significantly greater in the "below ILM" than the "above ILM" group.

Imaging in diabetic retinopathy

While the primary method for evaluating diabetic retinopathy involves direct and indirect ophthalmoscopy, various imaging modalities are of significant utility in the screening, evaluation, diagnosis, and treatment of different presentations and manifestations of this disease. This manuscript is a review of the important imaging modalities that are used in diabetic retinopathy, including color fundus photography, fluorescein angiography, B-scan ultrasonography, and optical coherence tomography. The article will provide an overview of these different imaging techniques and how they can be most effectively used in current practice.

Comparison of laser iridotomy using short duration 532-nm Nd: YAG laser (PASCAL) vs conventional laser in dark irides

AIM

To evaluate the outcome of laser iridotomy using 532-nm Nd: YAG laser (PASCAL) with short pulse duration and Nd: YAG laser compared to conventional combined laser iridotomy.

METHODS

Retrospective, nonrandomized, comparative case series. Forty-five eyes of 34 patients underwent laser iridotomy. Twenty-two eyes underwent iridotomy using short duration PASCAL and Nd: YAG laser, and 23 eyes underwent iridotomy using conventional combined laser method. The average settings of PASCAL were 60 µm and 700-900 mW with a short duration of 0.01s to reduce the total applied energy. The conventional laser was 50 µm and 700-900 mW for 0.1s. After photocoagulation with these laser, the Nd: YAG laser was added in each group. Endothelial cell counts of pre-iridotomy and 2mo after iridotomy were measured and compared.

RESULTS

All eyes completed iridotomy successfully. The total energy used in the PASCAL group was 1.85±1.17 J. Compared to conventional laser 13.25±1.67 J, the energy used was very small due to the short exposure time of PASCAL. Endothelial cell counts were reduced by 0.88% in the PASCAL group and 6.72% in the conventional laser group (P=0.044). The change in corneal endothelial cell counts before and after iridotomy was significant in conventional combined laser iridotomy group (P=0.004).

CONCLUSION

Combined PASCAL and Nd:YAG laser iridotomy is an effective and safe technique in the dark brown irides of Asians. Furthermore, the short duration of exposure in PASCAL offers the advantages of reducing the total energy used and minimizing the corneal damage.

New treatments for diabetic retinopathy

Diabetic retinopathy is the major cause of vision loss in middle-aged adults. Alteration of the blood-retinal barrier (BRB) is the hallmark of diabetic retinopathy and, subsequently, hypoxia may result in retinal neovascularization. Tight control of systemic factors such as blood glucose, blood pressure and blood lipids is essential in the management of this disease. Vascular endothelial growth factor (VEGF) is one of the most important factors responsible for alteration of the BRB. The introduction of anti-VEGF agents has revolutionized the therapeutic strategies used in people with diabetic retinopathy, and the use of laser therapy has been modified. In the present article, we examine the clinical features and pathophysiology of diabetic retinopathy and review the current status of new treatment recommendations for this disease, and also explore some possible future therapies.

Advances in diabetic retinopathy

Diabetic retinopathy (DR) is a complication of long-term diabetes mellitus (DM). Over the last 2 decades lot of work has been on early diagnosis of DR and screening programs have been designed to help the masses. Large numbers of clinical studies have been done for patients of diabetes and DR wherein the role of blood sugar control, metabolic control, role of oral medicines for DR, role of imaging, fluorescein angiography, and retinal photocoagulation has been studied. Newer treatment modalities are being devised and studied for better patient care. We discuss these issues in our review highlight and newer advances over the last few years.