Diabetic Retinopathy Clinical Research Network. A randomized trial comparing intravitreal triamcinolone acetonide and focal/grid photocoagulation for diabetic macular edema

Visual dysfunction associated with diabetic retinopathy

Diabetic retinopathy is a leading cause of blindness and is commonly viewed as a vascular complication of diabetes mellitus. However, diabetes mellitus causes visual dysfunction before the onset of clinically visible microvascular changes associated with diabetic retinopathy. Thus, viewing diabetic retinopathy more generally as a neurovascular disease may lead to an improved understanding of the mechanisms responsible for vision loss. This article reviews the impact of diabetes mellitus on inner and outer retinal visual and electrophysiologic function and advocates for a multimodal approach to the study of diabetic retinopathy.

Effect of systemic medications on onset and progression of diabetic retinopathy

Diabetic retinopathy remains a leading cause of visual loss worldwide. Patients with diabetes mellitus commonly have multiple comorbidities treated with a wide variety of medications. Systemic medications that target glycemic control and coexisting conditions may have beneficial or deleterious effects on the onset or progression of diabetic retinopathy. In addition, data is accumulating to suggest that the use of systemic therapy primarily to address ocular complications of diabetic retinopathy may be a promising therapeutic approach. This article reviews our current understanding of the ocular-specific effects of systemic medications commonly used by patients with diabetes mellitus, including those directed at control of hyperglycemia, dyslipidemia, hypertension, cardiac disease, anemia, inflammation and cancer. Current clinical evidence is strongest for the use of angiotensin-converting enzyme inhibitors and angiotensin-2 receptor blockers in preventing the onset or slowing the progression of early diabetic retinopathy. To a more limited extent, evidence of a benefit of fibrates for diabetic macular edema exists. Numerous other agents hold considerable promise or potential risk. Thus, these compounds must undergo further rigorous study to determine the actual clinical efficacy and adverse effects before definitive therapeutic care recommendations can be offered.

The multifactorial nature of retinal vascular disease

Retinal vascular disease is the most common cause of macular edema (ME). While there are several etiologies of vascular compromise and subsequent macular leakage, diabetic retinopathy is the most prevalent and continues to challenge ophthalmologists and frustrate patients due to its refractory nature. In response to this epidemic, diabetic ME (DME) along with cystoid ME (CME) have been areas of active investigation both in the clinic and the laboratory. Several decades of basic science research have revealed a growing and complex array of cytokine growth factors and proinflammatory mediators which are capable of inciting the cellular changes that result in accumulation of fluid within the retina. Much of this new molecular foundation provides the current and fundamental scaffold for understanding the pathologic process of ME while simultaneously identifying potential therapeutic targets. Whereas CME has classically been treated with corticosteroids and nonsteroidal antiinflammatory drugs, recent clinical studies have demonstrated improved visual outcomes for DME treatment with light focal/grid laser, corticosteroids and anti-vascular endothelial growth factor antibodies. Yet, each of these treatments has differential effects on the multifactorial mechanisms of ME. This article reviews the anatomical, cellular and molecular derangements associated with ME and highlights specific pathways targeted by current treatments.

Diabetic retinopathy

Diabetic retinopathy is a common and specific microvascular complication of diabetes, and remains the leading cause of preventable blindness in working-aged people. It is identified in a third of people with diabetes and associated with increased risk of life-threatening systemic vascular complications, including stroke, coronary heart disease, and heart failure. Optimum control of blood glucose, blood pressure, and possibly blood lipids remains the foundation for reduction of risk of retinopathy development and progression. Timely laser therapy is effective for preservation of sight in proliferative retinopathy and macular oedema, but its ability to reverse visual loss is poor. Vitrectomy surgery might occasionally be needed for advanced retinopathy. New therapies, such as intraocular injection of steroids and antivascular endothelial growth-factor agents, are less destructive to the retina than are older therapies, and could be useful in patients who respond poorly to conventional therapy. The outlook for future treatment modalities, such as inhibition of other angiogenic factors, regenerative therapy, and topical therapy, is promising.

Current concepts in intravitreal drug therapy for diabetic retinopathy

Diabetic retinopathy (DR) is a major cause of preventable blindness in the developed countries. Despite the advances in understanding and management of DR, it remains a challenging condition to manage. The standard of care for patients with DR include strict metabolic control of hyperglycemia, blood pressure control, normalization of serum lipids, prompt retinal laser photocoagulation and vitrectomy. For patients who respond poorly and who progressively lose vision in spite of the standard of care, intravitreal administration of steroids or/and anti-vascular endothelial growth factor (anti-VEGF) drugs appear to be a promising second-line of therapy. This review discusses the current concepts and the role of these novel therapeutic approaches in the management of DR.

Relationship between optical coherence tomography retinal parameters and visual acuity in diabetic macular edema

PURPOSE

To investigate the relationship between optical coherence tomography (OCT)-derived measurements of retinal morphology and visual acuity in patients with diabetic macular edema.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

A total of 67 consecutive patients (67 eyes) with diabetic macular edema (DME) who underwent Stratus OCT imaging (Carl Zeiss Meditec, Inc., Dublin, CA).

METHODS

Best-corrected Snellen visual acuity was recorded for each patient. Raw exported Stratus OCT images for each patient were analyzed using custom software entitled "OCTOR," which allows the precise positioning of prespecified boundaries on individual B-scans. Thickness, volume, and intensity were calculated for neurosensory retina and subretinal fluid. In addition, photoreceptor outer segment (POS) thickness was quantified.

MAIN OUTCOME MEASURES

Optical coherence tomography-derived measurements of retinal morphology and visual acuity.

RESULTS

The Spearman coefficient values (r) of the correlation between OCTOR-derived measurements of central subfield thickness, intensity, subretinal fluid volume, and POS thickness and the logarithm of the minimum angle of resolution visual acuities were 0.3428 (P = 0.005), -0.2658 (P = 0.03), -0.2683 (P = 0.38), and -0.3703 (P = 0.002), respectively. Multivariate models with stepwise selection revealed a cumulative R(2) of 0.4305 in the total study population, with R(2) of 0.4999 and 0.7628 in the untreated and prior focal laser groups, respectively.

CONCLUSIONS

Subanalysis and quantification of OCT features in eyes with DME seem to be of value. In particular, POS thickness seems to be an important predictor of function and visual acuity in patients with DME.

Steroid injection in addition to macular laser grid photocoagulation in diabetic macular oedema: a systematic review

OBJECTIVES

This study aimed to evaluate the evidence for the effects of steroid injection in addition to macular laser grid (MLG) photocoagulation versus those of MLG photocoagulation alone on visual acuity (VA) in patients with diabetic macular oedema (DMO).

METHODS

An extensive literature search in Medline (PubMed), Experta Medica (EMBASE) and the Cochrane Library (CENTRAL) using synonyms for MLG photocoagulation, steroid injection and DMO found 181 articles. Of the articles that met selection criteria, three studies in which patients receiving MLG photocoagulation were randomized to additional pretreatment with steroids provided the best available evidence. In addition to VA, central foveal thickness (CFT) was measured at baseline and at 6 months in all three studies.

RESULTS

Two studies, with total populations of 73 and 42 eyes, respectively, reported no additional effect of steroid injection on VA. One study, with a total of 41 eyes, reported a beneficial effect of pretreatment with steroids on VA of -0.21 ETDRS logMAR units. All three studies reported larger reductions in CFT in eyes pretreated with steroids, the smallest of which was 64 microm.

CONCLUSIONS

Although there is a greater reduction in CFT in eyes pretreated with steroids, this does not consistently result in higher VA. The literature search does not provide sufficiently strong evidence to recommend steroid injection before MLG photocoagulation in DMO.

[Glaucoma and retinal surgery]

In the therapeutic approach to complex glaucomas different initial situations were considered: pre-existing glaucoma, induction of glaucoma after vitreoretinal surgery and antiglaucomatous procedures. In pre-existing glaucoma and after filtering surgery maintenance of the filtering bleb requires a vitreoretinal approach for conjunctiva preservation with techniques such as pneumatic retinopexy or small gauge vitrectomy. After vitreoretinal surgery an increase in intraocular pressure (IOP) is common. Secondary glaucoma may occur after scleral buckling and after vitrectomy with or without gas or silicone oil tamponade as well as after application of steroids. Angle closure glaucoma after scleral buckling develops because of congestion and anterior rotation of the ciliary body. Vitreous tamponades with expansive or saturated gases may cause angle-closure glaucoma with or without pupillary blockage and may critically shorten ocular perfusion. Postoperative checks, immediate action and a ban on boarding aircraft over the period of intraocular gas tamponade prevent permanent damage to the eye. The majority of secondary glaucomas can effectively be controlled by topical medication and adequate postoperative posture of the patient. Besides the temporary use of systemic antiglaucomatous medication or laser therapy, very rarely in cases of massive swelling or overfill, a direct intervention, such as partial gas or silicone oil removal is required. A prophylactic inferior peripheral iridectomy prevents pupillary blockage in aphakic eyes with intraocular tamponade. In cases of heavy silicone oil use, the peripheral iridectomy is placed in the superior position. Nd:YAG laser application will regulate IOP in cases of occlusion. Secondary glaucoma due to silicone oil emulsification overload is treated by trabecular meshwork aspiration and lavage. In refractory glaucoma repetitive cyclophotocoagulation and drainage implants represent an approved method for long-term IOP regulation. The underlying cause of secondary glaucoma after vitreoretinal surgery is often multifactorial in nature and may benefit from an exact analysis for an adequate and successful treatment regimen.

Pharmacotherapeutic efficacy of preservative-free intravitreal triamcinolone acetonide

Preservative-free formulations of triamcinolone acetonide have recently been introduced to the market over concerns of local toxicity of the vehicle and preservatives, including benzyl alcohol in the original formulation, which was not designed for intraocular use. The pharmacokinetics and pharmacodynamics of intravitreal triamcinolone (IVTA) are discussed. The therapeutic effects of IVTA include improvement of visual acuity and reduction of macular edema. However, ongoing treatment is usually required to maintain its effects. The efficacy of IVTA for both FDA-approved and 'off-labeled' indications is reviewed. Elevation of intraocular pressure and cataract formation are the two major side effects of IVTA; these are manageable but require close long-term follow-up. More studies are required to determine the optimal dosage and treatment frequency in different posterior segment disease.

Randomized trial evaluating ranibizumab plus prompt or deferred laser or triamcinolone plus prompt laser for diabetic macular edema

OBJECTIVE

Evaluate intravitreal 0.5 mg ranibizumab or 4 mg triamcinolone combined with focal/grid laser compared with focal/grid laser alone for treatment of diabetic macular edema (DME).

DESIGN

Multicenter, randomized clinical trial.

PARTICIPANTS

A total of 854 study eyes of 691 participants with visual acuity (approximate Snellen equivalent) of 20/32 to 20/320 and DME involving the fovea.

METHODS

Eyes were randomized to sham injection + prompt laser (n=293), 0.5 mg ranibizumab + prompt laser (n=187), 0.5 mg ranibizumab + deferred (> or =24 weeks) laser (n=188), or 4 mg triamcinolone + prompt laser (n=186). Retreatment followed an algorithm facilitated by a web-based, real-time data-entry system.

MAIN OUTCOME MEASURES

Best-corrected visual acuity and safety at 1 year.

RESULTS

The 1-year mean change (+/-standard deviation) in the visual acuity letter score from baseline was significantly greater in the ranibizumab + prompt laser group (+9+/-11, P<0.001) and ranibizumab + deferred laser group (+9+/-12, P<0.001) but not in the triamcinolone + prompt laser group (+4+/-13, P=0.31) compared with the sham + prompt laser group (+3+/-13). Reduction in mean central subfield thickness in the triamcinolone + prompt laser group was similar to both ranibizumab groups and greater than in the sham + prompt laser group. In the subset of pseudophakic eyes at baseline (n=273), visual acuity improvement in the triamcinolone + prompt laser group appeared comparable to that in the ranibizumab groups. No systemic events attributable to study treatment were apparent. Three eyes (0.8%) had injection-related endophthalmitis in the ranibizumab groups, whereas elevated intraocular pressure and cataract surgery were more frequent in the triamcinolone + prompt laser group. Two-year visual acuity outcomes were similar to 1-year outcomes.

CONCLUSIONS

Intravitreal ranibizumab with prompt or deferred laser is more effective through at least 1 year compared with prompt laser alone for the treatment of DME involving the central macula. Ranibizumab as applied in this study, although uncommonly associated with endophthalmitis, should be considered for patients with DME and characteristics similar to those in this clinical trial. In pseudophakic eyes, intravitreal triamcinolone + prompt laser seems more effective than laser alone but frequently increases the risk of intraocular pressure elevation.

A prospective randomized trial of intravitreal bevacizumab or laser therapy in the management of diabetic macular edema (BOLT study) 12-month data: report 2

PURPOSE

To report the findings at 1 year of a study comparing repeated intravitreal bevacizumab (ivB) and modified Early Treatment of Diabetic Retinopathy Study (ETDRS) macular laser therapy (MLT) in patients with persistent clinically significant diabetic macular edema (CSME).

DESIGN

Prospective, randomized, masked, single-center, 2-year, 2-arm clinical trial.

PARTICIPANTS

A total of 80 eyes of 80 patients with center-involving CSME and at least 1 prior MLT.

METHODS

Subjects were randomized to either ivB (6 weekly; minimum of 3 injections and maximum of 9 injections in the first 12 months) or MLT (4 monthly; minimum of 1 treatment and maximum of 4 treatments in the first 12 months).

MAIN OUTCOME MEASURES

The primary end point was the difference in ETDRS best-corrected visual acuity (BCVA) at 12 months between the bevacizumab and laser arms.

RESULTS

The baseline mean ETDRS BCVA was 55.7+/-9.7 (range 34-69) in the bevacizumab group and 54.6+/-8.6 (range 36-68) in the laser arm. The mean ETDRS BCVA at 12 months was 61.3+/-10.4 (range 34-79) in the bevacizumab group and 50.0+/-16.6 (range 8-76) in the laser arm (P = 0.0006). Furthermore, the bevacizumab group gained a median of 8 ETDRS letters, whereas the laser group lost a median of 0.5 ETDRS letters (P = 0.0002). The odds of gaining > or =10 ETDRS letters over 12 months were 5.1 times greater in the bevacizumab group than in the laser group (adjusted odds ratio, 5.1; 95% confidence interval, 1.3-19.7; P = 0.019). At 12 months, central macular thickness decreased from 507+/-145 microm (range 281-900 microm) at baseline to 378+/-134 microm (range 167-699 microm) (P<0.001) in the ivB group, whereas it decreased to a lesser extent in the laser group, from 481+/-121 microm (range 279-844 microm) to 413+/-135 microm (range 170-708 microm) (P = 0.02). The median number of injections was 9 (interquartile range [IQR] 8-9) in the ivB group, and the median number of laser treatments was 3 (IQR 2-4) in the MLT group.

CONCLUSIONS

The study provides evidence to support the use of bevacizumab in patients with center-involving CSME without advanced macular ischemia.

Nonsteroidal anti-inflammatory drugs in ophthalmology

Nonsteroidal anti-inflammatory drugs (NSAIDs) are increasingly employed in ophthalmology to reduce miosis and inflammation, manage scleritis, and prevent and treat cystoid macular edema associated with cataract surgery. In addition, they may decrease postoperative pain and photophobia associated with refractive surgery and may reduce the itching associated with allergic conjunctivitis. In recent years, the U.S. Food and Drug Administration has approved new topical NSAIDs, and previously approved NSAIDs have been reformulated. These additions and changes result in different pharmacokinetics and dosing intervals, which may offer therapeutic advantages. For example, therapeutic effects on diabetic retinopathy and age-related macular degeneration may now be achievable. We provide an updated review on NSAIDs and a summary of their current uses in ophthalmology with attention to potential future applications.

A proposed method of logarithmic transformation of optical coherence tomography data for use in clinical research

PURPOSE

To evaluate a logarithmic transformation of retinal thickness measurements from optical coherence tomography as a new approach to assess clinically meaningful changes in retinal thickness.

DESIGN

Methodologic, evidence-based review.

METHODS

Standard published approaches for assessing change in retinal thickness over time, as measured by optical coherence tomography (OCT), were compared with a new approach based on a logarithmic transformation of the retinal thickness data. Comparative examples were derived using published data from a clinical trial comparing intravitreal corticosteroid injections for diabetic macular edema with standard laser treatment.

MAIN OUTCOME MEASURES

Comparative examples using Diabetic Retinopathy Clinical Research Network data.

RESULTS

Logarithmic transformation of retinal thickness data results in a more normalized distribution of OCT data and allows for data analyses assessing proportionate changes in retinal thickness during follow-up.

CONCLUSIONS

For analysis of grouped data, a logarithmic transformation of the OCT retinal thickness measurements (logOCT) provides several analytic advantages. Distributions of retinal thickness in groups of eyes with diabetic macular edema, and many other causes of macular thickening, tend to be skewed to the right; the logOCT transformation tends to normalize these distributions, which has value for statistical comparisons. For assessing whether the observed OCT change in a patient is real (and not due to testing variability), a 1-step log scale change exceeds the measurement error for all degrees of retinal thickness in current instruments. In addition, this log scale is similar to the logarithm of the minimum angle of resolution (logMAR) scale used for visual acuity. Steps on the log scale for change in thickness seem to be better related to clinical importance than the actual change in microns because each step on the log scale is the same proportionate change in thickness, with a 3-step change equaling a halving or doubling of thickness, regardless of the baseline value. Transformation of OCT retinal thickness data to logOCT may assist in the assessment of clinically meaningful changes in retinal thickness just as use of the logMAR scale has helped to assess clinically meaningful changes in visual acuity.

Vitrectomy outcomes in eyes with diabetic macular edema and vitreomacular traction

PURPOSE

To evaluate vitrectomy for diabetic macular edema (DME) in eyes with at least moderate vision loss and vitreomacular traction.

DESIGN

Prospective cohort study.

PARTICIPANTS

The primary cohort included 87 eyes with DME and vitreomacular traction based on investigator's evaluation, visual acuity 20/63-20/400, optical coherence tomography (OCT) central subfield >300 microns and no concomitant cataract extraction at the time of vitrectomy.

METHODS

Surgery was performed according to the investigator's usual routine. Follow-up visits were performed after 3 months, 6 months (primary end point), and 1 year.

MAIN OUTCOME MEASURES

Visual acuity, OCT retinal thickening, and operative complications.

RESULTS

At baseline, median visual acuity in the 87 eyes was 20/100 and median OCT thickness was 491 microns. During vitrectomy, additional procedures included epiretinal membrane peeling in 61%, internal limiting membrane peeling in 54%, panretinal photocoagulation in 40%, and injection of corticosteroids at the close of the procedure in 64%. At 6 months, median OCT central subfield thickness decreased by 160 microns, with 43% having central subfield thickness <250 microns and 68% having at least a 50% reduction in thickening. Visual acuity improved by > or =10 letters in 38% (95% confidence interval, 28%-49%) and deteriorated by > or =10 letters in 22% (95% confidence interval, 13%-31%). Postoperative complications through 6 months included vitreous hemorrhage (5 eyes), elevated intraocular pressure requiring treatment (7 eyes), retinal detachment (3 eyes), and endophthalmitis (1 eye). Few changes in results were noted between 6 months and 1 year.

CONCLUSIONS

After vitrectomy performed for DME and vitreomacular traction, retinal thickening was reduced in most eyes. Between 28% and 49% of eyes with characteristics similar to those included in this study are likely to have improvement of visual acuity, whereas between 13% and 31% are likely to have worsening. The operative complication rate is low and similar to what has been reported for this procedure. These data provide estimates of surgical outcomes and serve as a reference for future studies that might consider vitrectomy for DME in eyes with at least moderate vision loss and vitreomacular traction.

Sustained ocular delivery of fluocinolone acetonide by an intravitreal insert

PURPOSE

To compare Iluvien intravitreal inserts that release 0.2 or 0.5 microg/day of fluocinolone acetonide (FA) in patients with diabetic macular edema (DME).

DESIGN

Prospective, randomized, interventional, multicenter clinical trial.

PARTICIPANTS

We included 37 patients with DME.

METHODS

Subjects with persistent DME despite > or = 1 focal/grid laser therapy were randomized 1:1 to receive an intravitreal insertion of a 0.2- or a 0.5-microg/day insert.

MAIN OUTCOME MEASURES

The primary end point was aqueous levels of FA throughout the study with an important secondary outcome of the change from baseline in best-corrected visual acuity (BCVA) at month 12.

RESULTS

The mean aqueous level of FA peaked at 3.8 ng/ml at 1 week and 1 month after administration of a 0.5-microg/day insert and was 3.4 and 2.7 ng/ml 1 week and 1 month after administration of a 0.2-microg/day insert. For both inserts, FA levels decreased slowly thereafter and were approximately 1.5 ng/ml for each at month 12. The mean change from baseline in BCVA was 7.5, 6.9, and 5.7 letters at months 3, 6, and 12, respectively, after administration of a 0.5 microg/day-insert and was 5.1, 2.7, and 1.3 letters at months 3, 6, and 12, respectively, after administration of a 0.2-microg/day insert. There was a mild increase in mean intraocular pressure after administration of 0.5-microg/day inserts, but not after administration of 0.2-microg/day inserts.

CONCLUSIONS

The FA intravitreal inserts provide excellent sustained intraocular release of FA for > or = 1 year. Although the number of patients in this trial was small, the data suggest that the inserts provide reduction of edema and improvement in BCVA in patients with DME with mild effects on intraocular pressure over the span of 1 year.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Preliminary assessment of celecoxib and microdiode pulse laser treatment of diabetic macular edema

PURPOSE

Inflammation may play an important role in the pathogenesis of diabetic macular edema, a major cause of vision loss in persons with diabetes. The purpose of this study was to evaluate combined antiinflammatory therapy and laser approaches for treating patients with diabetic macular edema.

METHODS

In this prospective, factorial, randomized, multicenter trial, we compared cyclo-oxygenase-2 inhibitor (celecoxib) with placebo and diode grid laser with standard Early Treatment Diabetic Retinopathy Study focal laser treatment in 86 participants with diabetic macular edema. The primary outcome is change in visual acuity of > or = 15 letters from baseline, and the secondary outcomes include a 50% reduction in the retinal thickening of diabetic macular edema measured by optical coherence tomography and a 50% reduction in leakage severity on fluorescein angiography.

RESULTS

Visual acuity and retinal thickening data from >2 years of follow-up did not show evidence of differences between the medical and laser treatments. However, participants assigned to the celecoxib group were more likely to have a reduction in fluorescein leakage when compared with the placebo group (odds ratio = 3.6; P < 0.01).

CONCLUSION

This short-term study did not find large visual function benefits of treatment with celecoxib or diode laser compared with those of standard laser treatment. A suggestive effect of celecoxib in reducing fluorescein leakage was observed.

Semiautomated intraocular laser surgery using handheld instruments

BACKGROUND AND OBJECTIVE

In laser retinal photocoagulation, hundreds of dot-like burns are applied. We introduce a robot-assisted technique to enhance the accuracy and reduce the tedium of the procedure.

MATERIALS AND METHODS

Laser burn locations are overlaid on preoperative retinal images using common patterns such as grids. A stereo camera/monitor setup registers and displays the planned burn locations overlaid on real-time video. Using an active handheld micromanipulator, a 7 x 7 grid of burns spaced 650 microm apart is applied to both paper slides and porcine retina in vitro using 30 milliseconds laser pulses at 532 nm. Two scenarios were tested: unaided, in which the micromanipulator is inert and the laser fires at a fixed frequency, and aided, in which the micromanipulator actively targets burn locations and the laser fires automatically upon target acquisition. Error is defined as the distance from the center of the observed burn mark to the preoperatively selected target location.

RESULTS

An experienced retinal surgeon performed trials with and without robotic assistance, on both paper slides and porcine retina in vitro. In the paper slide experiments at an unaided laser repeat rate of 0.5 Hz, error was 125+/-62 microm with robotic assistance and 149+/-76 microm without (P < 0.005), and trial duration was 70+/-8 seconds with robotic assistance and 97+/-7 seconds without (P < 0.005). At a repeat rate of 1.0 Hz, error was 129+/-69 microm with robotic assistance and 166+/-91 microm without (P < 0.005), and trial duration was 26+/-4 seconds with robotic assistance and 47+/-1 seconds without (P < 0.005). At a repeat rate of 2.0 Hz on porcine retinal tissue, error was 123+/-69 microm with robotic assistance and 203+/-104 microm without (P < 0.005).

CONCLUSION

Robotic assistance can increase the accuracy of laser photocoagulation while reducing the duration of the operation.

Viral retinitis after intravitreal triamcinolone injection in patients with predisposing medical comorbidities

PURPOSE

To review the cases of viral retinitis after intravitreal steroid administration at a single center, to estimate the incidence, and to propose risk factors for its occurrence.

DESIGN

Retrospective, observational case series.

METHODS

Seven hundred thirty-six intravitreal triamcinolone (IVTA) injections were administered in the clinic and operating room by 3 retina specialists at a single academic medical center between September 2002 and November 2008. Inclusion criteria were simply a history of 1 or more IVTA injections during the period. The overall incidence of viral retinitis after IVTA injection was calculated. Subsequently, a chart audit was performed to estimate the number of patients with immune-altering conditions who had received IVTA during the period, and the incidence within this subgroup was calculated.

RESULTS

Viral retinitis developed after IVTA injection in 3 patients, yielding an overall incidence of 3 in 736 or 0.41%. An estimated 334 injections were administered to patients with an immune-altering condition, including diabetes. All 3 of the patients in whom viral retinitis developed after IVTA injection possessed abnormal immune systems, yielding an incidence rate of 3 in 334 or 0.90% within this subgroup.

CONCLUSIONS

Our high reported incidence for this potentially devastating complication can be attributed to multiple factors, including coexisting medical immunocompromising comorbidities, a higher dose with a longer duration of local immunosuppression in the vitreous, multiple injections, as well as previous viral retinitis. Caution with a high index of clinical suspicion and frequent follow-up is advised in patients receiving IVTA injection with potentially immune-altering conditions, even after apparent immune recovery.

A review of clinical trials of anti-VEGF agents for diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a leading cause of vision loss in the working-age population worldwide. Many observational and preclinical studies have implicated vascular endothelial growth factor (VEGF) in the pathogenesis of DR, and recent successes with anti-VEGF therapy for age-related macular degeneration (AMD) have prompted research into the application of anti-VEGF drugs to DR. Here we review the numerous early studies that suggest an important potential role for anti-VEGF agents in the management of diabetic retinopathy.

CONCLUSIONS

For diabetic macular edema, phase II trials of intravitreal pegaptanib and intravitreal ranibizumab have shown short-term benefit in visual acuity. Intravitreal bevacizumab also has been shown to have beneficial short-term effects on both visual acuity and retinal thickness. For proliferative diabetic retinopathy (PDR), early studies suggest that intravitreal bevacizumab temporarily decreases leakage from diabetic neovascular lesions, but this treatment may be associated with tractional retinal detachment (TRD). Furthermore, several studies indicate that bevacizumab is likely to prove a helpful adjunct to diabetic pars plana vitrectomy (PPV) for TRD. Finally, three small series suggest a potential beneficial effect of a single dose of bevacizumab to prevent worsening of DME after cataract surgery. Use of anti-VEGF medications for any of these indications is off-label. Despite promising early reports on the safety of these medications, we eagerly await the results of large, controlled trials to substantiate the safety and efficacy of anti-VEGF drugs for diabetic retinopathy.

Factors associated with improvement and worsening of visual acuity 2 years after focal/grid photocoagulation for diabetic macular edema

PURPOSE

To identify factors associated with the visual acuity outcome after focal/grid photocoagulation for diabetic macular edema (DME) among eyes randomized to the focal/grid photocoagulation treatment group within the Diabetic Retinopathy Clinical Research Network (DRCR.net) trial comparing triamcinolone with focal/grid laser.

DESIGN

Multicenter, randomized, clinical trial.

PARTICIPANTS

Three hundred thirty eyes with DME assigned to the focal/grid photocoagulation group, visual acuity 20/40 to 20/320, and optical coherence tomography (OCT) central subfield thickness > or =250 microns.

METHODS

Eyes were treated with a protocol-defined photocoagulation technique, which was repeated at 4-month intervals for persistent or recurrent edema. Separate logistic regression models were used to evaluate the associations of demographic, clinical, OCT, and fundus photographic variables with visual acuity improvement or worsening of > or =10 letters from baseline to 2 years. The association of the initial visual acuity outcome after treatment with the subsequent visual acuity course also was evaluated.

MAIN OUTCOME MEASURES

Visual acuity measured with the electronic Early Treatment Diabetic Retinopathy Study method.

RESULTS

Worse baseline visual acuity was the only factor found to be associated with more frequent visual acuity improvement (P<0.001), and both greater baseline OCT-measured retinal volume (P = 0.001) and better baseline visual acuity (P = 0.009) were found to be associated with more frequent visual acuity worsening. Visual acuity outcomes were similar in eyes with and without prior macular or panretinal photocoagulation. The initial visual acuity outcome at 4 months was not generally predictive of the subsequent course. Many eyes that worsened > or =10 letters from baseline to 4 months subsequently improved, and many eyes that initially improved, subsequently worsened.

CONCLUSIONS

At this time, focal/grid photocoagulation remains the standard management for DME and these results do not alter this paradigm.

Optimal current and future treatments for diabetic macular oedema

Diabetic retinopathy is the most common cause of vision loss in working-age adults. Both inflammation and vascular endothelial growth factor (VEGF) play a critical role, modern and emerging treatments have centred on both laser photocoagulation and new pharmacologic strategies to improve the prognosis. Focal and grid photocoagulation, as described in the ETDRS trials, remain the gold standard of treatment. New classes of agents include long-acting steroid formulations delivered as intravitreal injections and also anti-VEGF agents. In addition, studies are under way to evaluate potential benefits from other novel agents, including those acting on the mammalian target of rapamycin pathway. In limited numbers of direct head-to-head comparisons, both steroids and anti-VEGF agents appear to be superior to conventional photocoagulation in reducing macular oedema in the first 4-6 months after treatment, although laser photocoagulation appears to be superior at time points of 1-2 years. In addition, there appear to be significant potential long-term complications of steroids including cataracts and glaucoma that may limit their use in certain patients. New methods of the laser delivery including shorter pulse durations and pattern scanning may also improve the effectiveness and risk profile of laser from the patient prospective. Finally, multi-modality therapy may play an increasingly important role.

Risk of endophthalmitis after intravitreal drug injection when topical antibiotics are not required: the diabetic retinopathy clinical research network laser-ranibizumab-triamcinolone clinical trials

OBJECTIVE

To report the incidence of endophthalmitis after intravitreal drug injection by means of a standardized procedure that does not require topical antibiotics, sterile gloves, or a sterile drape.

METHODS

Intravitreal injections of preservative-free triamcinolone acetonide or ranibizumab were administered in 2 prospective randomized clinical trials performed by the Diabetic Retinopathy Clinical Research Network. The standardized procedure for these trials requires the use of a topical combination product of povidone-iodine, a sterile lid speculum, and topical anesthetic, but does not require the use of topical antibiotics before, on the day of, or after injection.

RESULTS

As of February 23, 2009, a total of 3226 intravitreal injections of ranibizumab and 612 injections of preservative-free triamcinolone had been administered. Topical antibiotics were given on the day of injection in 361 (9.4%) of the 3838 cases, for several days after injection in 813 cases (21.2%), on the day of injection and after injection in 1388 cases (36.2%), and neither on the day of injection nor after injection in 1276 cases (33.3%). Three cases of culture-positive endophthalmitis occurred after ranibizumab injections (0.09%), and no cases occurred after triamcinolone injections. In all 3 cases of endophthalmitis, topical antibiotics were given for several days after the injection but not before injection.

CONCLUSIONS

The results suggest that a low rate of endophthalmitis can be achieved by means of a protocol that includes use of topical povidone-iodine, a sterile lid speculum, and topical anesthetic, but does not require topical antibiotics, sterile gloves, or a sterile drape. Trial Registration clinicaltrials.gov Identifiers: NCT00444600 and NCT00445003.

Prospective evaluation of visual acuity assessment: a comparison of snellen versus ETDRS charts in clinical practice (An AOS Thesis)

THE PURPOSE OF THIS STUDY WAS TWOFOLD

first, to prospectively compare visual acuity (VA) scores obtained with Snellen charts versus Early Treatment Diabetic Retinopathy Study (ETDRS) charts in a "real world" retinal practice, and second, to see if there was a difference in visual acuity measurements obtained with ETDRS charts starting at 4 or 2 meters.

METHODS

Prospective, consecutive evaluation of patients who underwent best-corrected visual acuity testing of their right eye performed at a single seating by the same experienced, certified vision examiner in the same room with standardized low light conditions using a projected Snellen chart at 20 feet, and two different back-illuminated ETDRS charts placed 4 and 2 meters from the patient.

RESULTS

One hundred sixty-three eyes were included in the study. The mean Snellen VA was 0.67 logMAR (20/94), ETDRS VA at 4 meters was 0.54 logMAR (~20/69), and ETDRS VA at 2 meters was 0.51 logMAR (~20/65). The mean difference was 6.5 letters better on the ETDRS chart (P=.000000001). As the VA worsened, there was increased variability between the charts and the mean discrepancy between charts also increased. Subgroup analysis revealed the greatest difference between charts was in the poor vision subgroup (<20/200) with a difference of 0.2 logMAR (10 letters; P=.0000002). Patients with exudative age-related macular degeneration (AMD) had the greatest disparity on vision testing, but patients with dry AMD and diabetic retinopathy also exhibited significant differences.

CONCLUSIONS

Visual acuity scores were significantly better on ETDRS charts compared to Snellen charts. The difference was greatest with poor visual acuity (<20/200) and in patients with exudative AMD. Thus, caution should be exercised when comparing data using the different charts.

Exploratory analysis of diabetic retinopathy progression through 3 years in a randomized clinical trial that compares intravitreal triamcinolone acetonide with focal/grid photocoagulation

OBJECTIVE

To compare the effect of intravitreal triamcinolone acetonide with focal/grid photocoagulation on the progression of diabetic retinopathy.

METHODS

We performed an exploratory analysis of participants with diabetic macular edema randomly assigned to receive laser therapy or intravitreal triamcinolone acetonide (1 or 4 mg). Fundus photographs were obtained at baseline and 1, 2, and 3 years. The main outcome measure was progression to proliferative diabetic retinopathy or worsening of 2 or more severity levels on reading-center masked assessment of 7-field fundus photographs, plus additional eyes that received panretinal photocoagulation or had a vitreous hemorrhage.

RESULTS

From July 15, 2004, through May 5, 2006, 840 eyes from 693 participants were enrolled in the study and randomly assigned to receive laser therapy (n = 330), 1 mg of triamcinolone acetonide (n = 256), or 4 mg of triamcinolone acetonide (n = 254). The cumulative probability of progression of retinopathy at 2 years was 31% (laser group), 29% (1-mg group), and 21% (4-mg group) (P = .64 in the 1-mg group and .005 in the 4-mg group compared with the laser group). These differences appeared to be sustained at 3 years.

CONCLUSIONS

Intravitreal triamcinolone acetonide (4 mg) appeared to reduce the risk of progression of diabetic retinopathy. Given the exploratory nature of this analysis and because intravitreal triamcinolone adverse effects include cataract formation and glaucoma, use of this treatment merely to reduce the rates of progression of proliferative diabetic retinopathy or worsening of the level of diabetic retinopathy does not seem warranted at this time.

The Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) study system for evaluation of optical coherence tomograms: SCORE study report 4

OBJECTIVE

To describe grading procedures for optical coherence tomographic (OCT) images of participants in the Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) Study.

METHODS

Optical coherence tomograms were taken at clinical sites with the Stratus OCT using fast macular and crosshair scan protocols. Paper prints of images were evaluated at a central reading center. Quality evaluation identified the accuracy of OCT-measured retinal thickness data and was categorized as good, fair, borderline, or ungradable. Manual measurement of center point thickness was performed on borderline images. Morphological evaluation identified cystoid spaces, subretinal fluid, and vitreoretinal interface abnormalities. Reproducibility of grading was assessed through formal quality control exercises.

RESULTS

A randomly selected set of 106 images was identified for quality control. The first 2 annual regrades showed 91% and 89% intergrader agreement for OCT quality. Intraclass correlation for manually measured center point thickness was 0.99 per year. For morphological variables, intergrader agreement for cystoid spaces was 83% and 76%. Reproducibility for subretinal fluid and vitreoretinal interface abnormalities could not be interpreted owing to their limited presence in the sample.

CONCLUSION

Optical coherence tomogram evaluation procedures used in the SCORE Study are reproducible and can be used for multicenter longitudinal studies of retinal vein occlusion.

The course of response to focal/grid photocoagulation for diabetic macular edema

PURPOSE

The purpose of this study was to determine whether eyes with center-involved diabetic macular edema, treated with focal/grid photocoagulation, in which there is a reduction in central subfield thickness (CST) measured with optical coherence tomography after 16 weeks, will continue to improve if retreatment is deferred.

METHODS

This is a prospective, multicenter, observational, single-group focal/grid photocoagulation study of 122 eyes with center-involved diabetic macular edema (optical coherence tomography CST > or =250 microm). At the 16-week visit and continuing every 8 weeks, eyes were assessed for retreatment and additional laser treatment was deferred if the visual acuity letter score improved > or =5 letters or optical coherence tomography CST decreased > or =10% compared with the visit 16 weeks prior.

RESULTS

Of the 115 eyes that completed the 16-week visit, 54 (47%) had a decrease in CST by > or =10% compared with baseline. Of these, 26 (48%) had a CST > or =250 microm at 16 weeks and were evaluable at 32 weeks. Eleven (42%; 95% confidence interval, 23-63%) of the 26 eyes had a further decrease in CST > or =10% from 16 weeks to 32 weeks without further treatment.

CONCLUSION

Sixteen weeks after focal/grid laser for diabetic macular edema in eyes with a definite reduction, but not resolution, of central edema, 23% to 63% likely will continue to improve without additional treatment.

Visual acuity after intravitreal triamcinolone for diabetic macular edema refractory to laser treatment: a meta-analysis

OBJECTIVE

To quantify the effect on visual acuity of intravitreal triamcinolone for the treatment of laser-refractory diabetic macular edema (DME).

STUDY DESIGN

Meta-analysis of eligible studies identified by searching MEDLINE, EMBASE, the Cochrane Library, and Google.

PARTICIPANTS

7 randomized controlled trials and 3 cohort studies.

METHODS

A search of the literature between 1950 and September 2008 identified 540 articles. Studies that evaluated the efficacy of triamcinolone for the treatment of DME refractory to laser photocoagulation, reported visual acuity data, and compared the intervention with an appropriate control group were included. Exclusion criteria were studies of non-DME, triamcinolone used as an adjunct to another treatment, and triamcinolone delivery other than intravitreally.

RESULTS

Using a random-effects model, there was a statistically significant summary mean difference in visual acuity of -0.313 logarithm of the minimum angle of resolution (logMAR) units (95% CI -0.551, -0.074) after 1 month of follow-up. This difference declined to -0.125 logMAR units (95% CI -0.181, -0.070) by 3 months and to -0.043 logMAR units (95% CI -0.090, 0.003) by 6 months. No evidence of publication bias was present. There was a high level of heterogeneity in this group of studies (meta-analysis of 1-month follow-up data: Q-statistic = 21.987, p< 0.001), attributable primarily to study design.

CONCLUSIONS

These meta-analyses demonstrate that intravitreal triamcinolone results in a temporary improvement of visual acuity in patients with laser-refractory DME, with a peak benefit of approximately 3 lines of visual acuity 1 month postinjection.

Factors associated with variability in response of diabetic macular oedema after intravitreal triamcinolone

PURPOSE

To identify factors associated with variability in anatomical and functional response of diabetic macular oedema (DMO) after 4 mg of intravitreal triamcinolone acetonide (ivTA), and for recurrence of macular oedema.

DESIGN

Pooled analysis of individual data from two randomized controlled trials.

METHODS

This was a multicentre study involving 107 eyes with DMO administered 4 mg ivTA. Predictive factors for response to treatment were evaluated with linear regression analysis. Factors associated with time to recurrence of oedema were studied with Cox proportional hazards modelling. Main outcome measures were maximum improvement in optical coherence tomography (OCT)-measured central foveal thickness (CFT) and best-corrected visual acuity (BCVA), final CFT and BCVA at 12 months and time to oedema recurrence.

RESULTS

Greater reduction of retinal thickening occurred in eyes with worse baseline thickening (P < 0.001). There was also greater improvement of visual acuity in eyes with poorer preoperative BCVA levels (P < 0.001). Age, duration of oedema and previous macular laser treatment had no significant effect on maximal BCVA or CFT improvement. Eyes given 4 mg triamcinolone alone were more likely to develop recurrence of oedema at 12 months than those given a combination of 4 mg triamcinolone plus sequential laser (hazard ratio 2.60 [95% confidence interval: 1.45-4.67]).

CONCLUSION

Baseline OCT-measured retinal thickening and BCVA are important predictors of maximal anatomical and functional response of DMO to ivTA, respectively. Combination treatment strategy using sequential laser therapy may have a role in delaying recurrence of oedema after triamcinolone.

Intravitreal injection of therapeutic agents

BACKGROUND

Intravitreal injection (IVI) with administration of various pharmacological agents is a mainstay of treatment in ophthalmology for endopthalmitis, viral retinitis, age-related macular degeneration, cystoid macular edema, diabetic retinopathy, uveitis, vascular occlusions, and retinal detachment. The indications and therapeutic agents are reviewed in this study.

METHODS

A search of the English, German, and Spanish language MEDLINE database was conducted. A total of 654 references spanning the period through early 2008 were individually evaluated.

RESULTS

The advantage of the IVI technique is the ability to maximize intraocular levels of medications and to avoid the toxicities associated with systemic treatment. Intravitreal injection has been used to deliver several types of pharmacological agents into the vitreous cavity: antiinfective and antiinflammatory medications, immunomodulators, anticancer agents, gas, antivascular endothelial growth factor, and several others. The goal of this review is to provide a detailed description of the properties of numerous therapeutic agents that can be delivered through IVI, potential complications of the technique, and recommendations to avoid side effects.

CONCLUSION

The IVI technique is a valuable tool that can be tailored to the disease process of interest based on the pharmacological agent selected. This review provides the reader with a comprehensive summary of the IVI technique and its multitude of uses.

Comparison of clinically relevant findings from high-speed fourier-domain and conventional time-domain optical coherence tomography

PURPOSE

To compare the sensitivities of high-speed Fourier-domain optical coherence tomography (FD-OCT) and conventional time-domain (TD) OCT for the detection of clinical findings important in the management of common vitreoretinal disorders.

DESIGN

Prospective, observational study.

METHODS

FD-OCT scans (128 B scans x 512 A scans) were obtained using a prototype instrument (3 D-OCT; Topcon, Tokyo, Japan) in 50 eyes of 28 consecutive patients undergoing conventional high-resolution (6 B scans x 512 A scans) TD-OCT imaging (Stratus OCT; Carl Zeiss Meditec, Dublin, California, USA). Each image set was reviewed independently for the presence of clinical findings of interest, and device sensitivities were calculated.

RESULTS

The average sensitivity for detection of all features in this study was 94% for FD-OCT and 60% for TD-OCT. Clinical findings were identical between devices in 18% (9/50) of cases. FD-OCT detected features that were not visible on conventional OCT scans in 78% (39/50) of cases. FD-OCT was more sensitive than TD-OCT for the detection of multiple findings, including diffuse intraretinal edema (87% vs 60.9%), subretinal fluid (100% vs 46.2%), large pigment epithelium detachments (100% vs 81%), and subretinal tissue (100% vs 61.5%).

CONCLUSIONS

FD-OCT seems to be superior to TD-OCT for the detection of many clinically relevant features of vitreoretinal disease. The greater sensitivity of FD-OCT systems for the detection of intraretinal and subretinal fluid may be of particular importance for the treatment of patients with neovascular age-related macular edema. FD-OCT is likely to supplant TD-OCT as the standard of care for retinal specialists in the near future.

Intravitreal steroid versus macular laser for treatment of diabetic macular edema

Diabetic macular edema is a leading cause of vision loss in the United States. Focal/grid laser photocoagulation has been the gold standard for treatment over the past two decades. Intravitreal pharmacologic treatments increasingly have been used over the past 5 years. Various studies have shown the possible benefits of intravitreal corticosteroids and anti-vascular endothelial growth factors in the treatment of diabetic macular edema. However, focal/grid laser photocoagulation continues to be the only proven safe and effective treatment for diabetic macular edema.

Primary intravitreal bevacizumab for diffuse diabetic macular edema: the Pan-American Collaborative Retina Study Group at 24 months

PURPOSE

To report the 24-month anatomic and Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA) response after primary intravitreal bevacizumab (Avastin; Genentech, Inc., San Francisco, CA; 1.25 or 2.5 mg) in patients with diffuse diabetic macular edema (DDME). In addition, a comparison of the 2 different doses of intravitreal bevacizumab (IVB) used is presented.

DESIGN

Retrospective, multicenter, interventional, comparative case series.

PARTICIPANTS

The clinical records of 115 consecutive patients (139 eyes) with DDME at 11 centers from 8 countries were reviewed.

METHODS

Patients were treated with at least 1 intravitreal injection of 1.25 or 2.5 mg of bevacizumab. All patients were followed up for 24 months. Patients underwent ETDRS BCVA testing, ophthalmoscopic examination, optical coherence tomography (OCT), and fluorescein angiography (FA) at the baseline, 1-, 3-, 6-, 12-, and 24-month visits.

MAIN OUTCOME MEASURES

Changes in BCVA and OCT results.

RESULTS

The mean age of the patients was 59.4+/-11.1 years. The mean number of IVB injections per eye was 5.8 (range, 1-15 injections). In the 1.25-mg group at 1 month, BCVA improved from 20/150 (0.88 logarithm of the minimum angle of resolution [logMAR] units) to 20/107, 0.76 logMAR units (P<0.0001). The mean BCVA at 24 months was 20/75 (0.57 logMAR units; P<0.0001). Similar BCVA changes were observed in the 2.5-mg group: at 1 month, BCVA improved from 20/168 (0.92 logMAR units) to 20/118 (0.78 logMAR units; P = 0.02). The mean BCVA at 24 months was 20/114 (0.76 logMAR units; P<0.0001). In the 1.25-mg group, the mean central macular thickness (CMT) decreased from 466.5+/-145.2 microm at baseline to 332.2+/-129.6 microm at 1 month and 286.6+/-81.5 microm at 24 months (P<0.0001). Similar results were obtained in the 2.5-mg group.

CONCLUSIONS

Primary IVB at doses of 1.25 to 2.5 mg seem to provide stability or improvement in BCVA, OCT, and FA in DDME at 24 months. The results show no evident difference between IVB at doses of 1.25 or 2.5 mg.