Diabetic macular edema: pathogenesis and treatment

Dexamethasone intravitreal implant in combination with laser photocoagulation for the treatment of diffuse diabetic macular edema

PURPOSE

To evaluate Ozurdex (dexamethasone intravitreal implant [DEX implant]; Allergan, Inc, Irvine, CA) 0.7 mg combined with laser photocoagulation compared with laser alone for treatment of diffuse diabetic macular edema (DME).

DESIGN

Randomized, controlled, multicenter, double-masked, parallel-group, 12-month trial.

PARTICIPANTS

Two hundred fifty-three patients with retinal thickening and impaired vision resulting from diffuse DME in at least 1 eye (the study eye) were enrolled.

INTERVENTION

Patients were randomized to treatment in the study eye with DEX implant at baseline plus laser at month 1 (combination treatment; n = 126) or sham implant at baseline and laser at month 1 (laser alone; n = 127) and could receive up to 3 additional laser treatments and 1 additional DEX implant or sham treatment as needed.

MAIN OUTCOME MEASURES

The primary efficacy variable was the percentage of patients who had a 10-letter or more improvement in best-corrected visual acuity (BCVA) from baseline at month 12. Other key efficacy variables included the change in BCVA from baseline and the area of vessel leakage evaluated with fluorescein angiography. Safety variables included adverse events and intraocular pressure (IOP).

RESULTS

The percentage of patients who gained 10 letters or more in BCVA at month 12 did not differ between treatment groups, but the percentage of patients was significantly greater in the combination group at month 1 (P<0.001) and month 9 (P = 0.007). In patients with angiographically verified diffuse DME, the mean improvement in BCVA was significantly greater with DEX implant plus laser treatment than with laser treatment alone (up to 7.9 vs. 2.3 letters) at all time points through month 9 (P ≤ 0.013). Decreases in the area of diffuse vascular leakage measured angiographically were significantly larger with DEX implant plus laser treatment through month 12 (P ≤ 0.041). Increased IOP was more common with combination treatment. No surgeries for elevated IOP were required.

CONCLUSIONS

There was no significant between-group difference at month 12. However, significantly greater improvement in BCVA, as demonstrated by changes from baseline at various time points up to 9 months and across time based on the area under the curve analysis, occurred in patients with diffuse DME treated with DEX implant plus laser than in patients treated with laser alone.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Pharmacologic and clinical profile of dexamethasone intravitreal implant

The challenge in the treatment of chronic retinal diseases is to deliver effective therapy to the target tissues in the back of the eye while limiting drug exposure in nontarget tissues. Intravitreal placement provides the most targeted drug delivery, but repeated penetration of the globe to deliver intravitreal therapy can pose safety risks. A more effective strategy for the treatment of chronic retinal diseases would be to combine intravitreal placement with sustained drug delivery. The dexamethasone intravitreal (DEX) implant is a biodegradable sustained-release intravitreal drug delivery system that is approved for the treatment of macular edema following branch or central retinal vein occlusion and for noninfectious uveitis affecting the posterior segment of the eye. A single DEX implant has been shown to provide clinical benefits for up to 6 months in eyes with retinal vein occlusion or intermediate or posterior uveitis.

Drug updates and approvals: 2012 in review

Each year, the FDA approves many pharmaceuticals and products designed to treat or improve a patient's condition. The following is a sampling of some of the most important drugs approved in 2012 that specifically apply to nurse practitioner practice.

Review of Aflibercept for the Treatment of Neovascular Age-Related Macular Degeneration

The treatment of exudative age-related macular degeneration (AMD) has been completely transformed by the development of drugs that bind vascular endothelial growth factor (VEGF). The antibody-based VEGF inhibitors bevacizumab and ranibizumab usually prevent the enlargement of choroidal neovascular membranes, reduce vascular permeability, and improve visual acuity. The newest VEGF inhibitor, aflibercept, is a soluble fusion protein that binds all isoforms of VEGF-A, VEGF-B, and placental growth factor with high affinity. Preclinical studies demonstrated aflibercept's ability to prevent experimental neovascularization and tumor growth in animal models. In phase 3 trials for exudative AMD, patients who received aflibercept avoided moderate vision loss and experienced improved visual acuity comparable to those who received ranibizumab. Additionally, patients who were treated with aflibercept 2 mg every 8 weeks (after 3 monthly loading doses) had similar visual results to those treated every 4 weeks. When treated as needed during the second year of the trials, patients were able to last an average of 3 months between aflibercept injections. Since its regulatory approval, aflibercept has also been found to perform well as a salvage therapy for eyes that respond incompletely to ranibizumab and bevacizumab. Because aflibercept can be administered less frequently than ranibizumab, it promises to decrease the frequency of patients’ visits to physicians’ offices in addition to the overall cost of AMD therapy.

Fluocinolone acetonide and its potential in the treatment of chronic diabetic macular edema

Diabetic macular edema (DME) is a potentially sight-threatening disease that predominantly affects patients with type 2 diabetes. The pathogenesis is complex, with many contributing factors involved. In addition to overexpression of vascular endothelial growth factor in the diabetic eye, there is an inflammatory pathway that contributes to the breakdown of the blood-retina barrier and nonperfusion. In addition to vascular endothelial growth factor inhibitors, clinical and experimental investigations underline the great potential of steroids in the treatment of DME. Fluocinolone acetonide is currently the only corticosteroid approved for the treatment of DME in Europe. It is manufactured as an intravitreal insert, releasing fluocinolone acetonide at a rate of 0.2 μg per day. Phase III clinical studies have demonstrated that the beneficial effect of the fluocinolone acetonide insert lasts up to 3 years. Improvement in visual acuity was especially remarkable in patients with a prolonged duration of DME of at least 3 years at the initiation of therapy. Cataract formation occurs in nearly all phakic eyes treated, and needs to be considered when the indication for treatment is made. Given the efficacy versus potential complications of the insert, fluocinolone acetonide represents a promising second-line treatment option in patients with DME. Fluocinolone appears to be especially beneficial for patients whose options for visual recovery have seemed limited up until now.

Effect of a single intravitreal bevacizumab injection on different optical coherence tomographic patterns of diabetic macular oedema

PURPOSE

The aim of this study is to compare the therapeutic effect of a single intravitreal bevacizumab (IVB) injection in eyes with diabetic macular oedema (DMO) of different patterns determined by optical coherence tomography (OCT).

METHODS

Medical records of patients who had a single IVB injection for DMO were analysed retrospectively. Eyes with a clinically significant DMO and a central foveal thickness (CFT) of 250 μm or more determined by OCT were included in the analysis. Best-corrected visual acuity (BCVA), CFT and total macular volume values before and after the injection were recorded. Eyes were divided into sponge-like diffuse retinal thickening (DRT), cystoid macular oedema (CMO) and serous retinal detachment (SRD) groups according to the morphology on OCT.

RESULTS

A total of 92 eyes (42 with DRT, 31 with CMO and 19 with SRD) were included in the study. There was no statistically significant variation between three groups regarding the change in BCVA (P=0.695). CMO and SRD groups had greater reductions in their mean CFT, and the amount of reduction showed statistically significant variation between three groups (P=0.048). However, no statistically significant difference was found between groups in terms of percentage of change in CFT (P=0.278).

CONCLUSION

CMO and SRD subtypes are associated with a greater reduction in the CFT than the DRT subtype. Although the change in BCVA was not significantly different between groups, the DRT group showed markedly better visual improvement in proportion to the decrease in CFT.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Comparison of intravitreal bevacizumab, intravitreal triamcinolone acetonide, and macular grid augmentation in refractory diffuse diabetic macular edema: A prospective, randomized study

BACKGROUND

In spite of laser being the gold standard treatment for Diabetic Macular edema (DME), some patients do not respond to laser. Various treatment modalities are being tried in the management of refractory diffuse DME (DDME).

PURPOSE

To compare the efficacy of intravitreal bevacizumab (IVB), intravitreal triamcinolone acetonide (IVTA), and macular grid augmentation in the management of refractory DDME.

SETTINGS AND DESIGN

Prospective randomized study in a tertiary eye care center.

MATERIALS AND METHODS

SIXTY PATIENTS WITH REFRACTORY DDME WERE RANDOMLY ASSIGNED TO THREE GROUPS: Group 1 received IVB (1.25 mg/0.05 ml), Group 2 received IVTA (4 mg/0.1ml), and Group 3 underwent laser augmentation. Primary outcome measures were best corrected visual acuity (BCVA) and central macular thickness (CMT) at the end of 6 months.

STATISTICS

Analysis was performed using SPSS 14.0

RESULTS

Group 1 and 2 showed significant improvement in mean BCVA from 20/160 at baseline to 20/80 and from 20/125 to 20/63, respectively, at 6 months (P < 0.05). These groups also showed a significant reduction in the mean CMT from 457 ± 151 μ at baseline to 316 ± 136 μ and from 394 ± 61 μ to 261 ± 85 μ, respectively, at 6 months (P < 0.05). Group 3 showed only small improvement in mean BCVA from 20/100 to 20/80 (P = 1.0) while mean CMT increased from 358 ± 89 μ at baseline to 395 ± 127 μ at 6 months (P = 0.191). Eight (40%) eyes in Group 2 had intraocular pressure (IOP) rise and 10 (50%) eyes developed cataract.

CONCLUSIONS

Both IVB and IVTA may be effective in the treatment of refractory DDME compared with macular grid augmentation. IVTA may be associated with side effects such as IOP rise and cataract formation.

Pathophysiology and treatment of diabetic retinopathy

In the past years, the management of diabetic retinopathy (DR) relied primarily on a good systemic control of diabetes mellitus, and as soon as the severity of the vascular lesions required further treatment, laser photocoagulation or vitreoretinal surgery was done to the patient. Currently, even if the intensive metabolic control is still mandatory, a variety of different clinical strategies could be offered to the patient. The recent advances in understanding the complex pathophysiology of DR allowed the physician to identify many cell types involved in the pathogenesis of DR and thus to develop new treatment approaches. Vasoactive and proinflammatory molecules, such as vascular endothelial growth factor (VEGF), play a key role in this multifactorial disease. Current properly designed trials, evaluating agents targeting VEGF or other mediators, showed benefits in the management of DR, especially when metabolic control is lacking. Other agents, directing to the processes of vasopermeability and angiogenesis, are under investigations, giving more hope in the future management of this still sight-threatening disease.

Psychometric validation of the Visual Function Questionnaire-25 in patients with diabetic macular edema

BACKGROUND

Diabetic Macular Edema (DME) is a common cause of impaired vision and blindness amongst diabetics. If not detected and treated early, the resulting vision loss can lead to considerable health costs and decreased health-related quality of life (HRQoL). The aim of this study was to provide evidence of the psychometric properties of the National Eye Institute - Visual Functioning Questionnaire (VFQ-25) for use in a cohort of DME patients who participated in a clinical efficacy and safety trial of pegaptinib sodium (Macugen).

METHODS

A phase 2/3 randomised, double masked trial evaluated pegaptanib injection versus sham injection in patients with DME. The analysis was conducted using baseline HRQoL data of the VFQ-25 and the EQ-5D, on a modified intent-to-treat sample of 235 patients. These measures were administered by a trained interviewer by telephone in all but one of the study countries, where face-to-face interviews were conducted in the clinic. The measures were completed in the week prior to baseline, and after 54 weeks of treatment. Distance visual acuity, measured according to the Early Treatment Diabetic Retinopathy Study (ETDRS), was assessed at all time points. Psychometric properties of the VFQ-25 assessed included domain structure, reliability, concurrent and construct validity, responsiveness.

RESULTS

The VFQ-25 was found to consist of 11 domains slightly different than those proposed. Nevertheless, none of the eight established multi-item scales met the criterion for further splitting and the VFQ-25 was scored as in the developers' instructions. Internal consistency reliability was demonstrated for six out of the eight original multi-item scales, with Cronbach's alpha ranging from 0.58 (Distance Activities) to 0.85 (Vision Specific: Dependency). The VFQ-25 domains generally showed a low to moderate correlation with EQ-5D visual analogue scale (range 0.16-0.43) and with the visual acuity score (range 0.10-0.41). Construct validity was upheld with higher VFQ-25 scores for patients who saw more letters according to the ETDRS. Almost all scales were shown to be responsive with Guyatt's statistic ranging from 0.10 to 0.56 at 54 weeks.

CONCLUSIONS

The VFQ-25 has evidence to support its validity and reliability for measuring HRQoL in DME. However, some operating characteristics of the instrument need further consideration and discussion in the case of DME patients. Further research is therefore warranted in this indication.

Nonsteroidal anti-inflammatory drugs for retinal disease

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used extensively in ophthalmology for pain and photophobia after photorefractive surgery and to reduce miosis, inflammation, and cystoid macular edema following cataract surgery. In recent years, the US Food and Drug Administration has approved new topical NSAIDs and previously approved NSAIDs have been reformulated. These changes may allow for greater drug penetration into the retina and thereby offer additional therapeutic advantages. For example, therapeutic effects on diabetic retinopathy and age-related macular degeneration may now be achievable. We provide an updated review on the scientific rationale and clinical use of NSAIDs for retinal disease.

Comparison of natural course, intravitreal triamcinolone and macular laser photocoagulation for treatment of mild diabetic macular edema

PURPOSE

To assess the natural course of the mild diabetic macular edema(DME) and to compare the visual outcomes with the patients with receiving either macular laser photocoagulation or intravitreal injection of triamcinolone acetonide(IVTA).

METHODS

28 eyes with central macular thickness (CMT) of between 250 to 300µm were followed without treatment and 48 eyes with CMT between 300 to 500µm had been divided into 3 subgroups according to treatment. We evaluated the best corrected visual acuity (BCVA) and CMT of natural course group and compared the BCVA and CMT of the patients who had been treated with IVTA or macular laser treatment.

RESULTS

The eyes with DME between 250 to 300µm showed no significant change in BCVA and CMT at 6 month. Among the eyes with DME between 300 to 500µm, all 3 subgroups showed no statistically significant change of BCVA at any follow up period and no significant difference was revealed among the subgroups. All subgroups showed significant reduction of CMT after 1 month and maintained until final follow-up and there was no significant difference among subgroups.

CONCLUSIONS

Mild DME between 250 to 500µm did not show significant worsening of BCVA or macular edema without any specific treatment.

Quantification of external limiting membrane disruption caused by diabetic macular edema from SD-OCT

PURPOSE

Disruption of external limiting membrane (ELM) integrity on spectral-domain optical coherence tomography (SD-OCT) is associated with lower visual acuity outcomes in patients suffering from diabetic macular edema (DME). However, no automated methods to detect ELM and/or determine its integrity from SD-OCT exist.

METHODS

Sixteen subjects diagnosed with clinically significant DME (CSME) were included and underwent macula-centered SD-OCT (512 × 19 × 496 voxels). Sixteen subjects without retinal thickening and normal acuity were also scanned (200 × 200 × 1024 voxels). Automated quantification of ELM disruption was achieved as follows. First, 11 surfaces were automatically segmented using our standard 3-D graph-search approach, and the subvolume between surface 6 and 11 containing the ELM region was flattened based on the segmented retinal pigment epithelium (RPE) layer. A second, edge-based graph-search surface-detection method segmented the ELM region in close proximity "above" the RPE, and each ELM A-scan was classified as disrupted or nondisrupted based on six texture features in the vicinity of the ELM surface. The vessel silhouettes were considered in the disruption classification process to avoid false detections of ELM disruption.

RESULTS

In subjects with CSME, large areas of disrupted ELM were present. In normal subjects, ELM was largely intact. The mean and 95% confidence interval (CI) of the detected disruption area volume for normal and CSME subjects were mean(normal) = 0.00087 mm(3) and CI(normal) = (0.00074, 0.00100), and mean(CSME) = 0.00461 mm(3) and CI(CSME) = (0.00347, 0.00576) mm(3), respectively.

CONCLUSIONS

In this preliminary study, we were able to show that automated quantification of ELM disruption is feasible and can differentiate continuous ELM in normal subjects from disrupted ELM in subjects with CSME. We have started determining the relationships of quantitative ELM disruption markers to visual outcome in patients undergoing treatment for CSME.

Diabetic macular edema: current and emerging therapies

Diabetic macular edema is a leading cause of vision impairment among people within the working- age population. This review discusses the pathogenesis of diabetic macular edema and the treatment options currently available for the treatment of diabetic macular edema, including for focal/grid photocoagulation, intravitreal corticosteroids and intravitreal anti-vascular endothelial growth factor agents. The biologic rationale for novel therapeutic agents, many of which are currently being evaluated in clinical trials, also is reviewed.

Diabetic macular edema: new trends in management

The treatment of diabetic macular edema may be evolving from a laser ablative approach into a pharmacotherapeutic approach. The exponential growth that has occurred over the past decade in the retinal pharmacotherapy field has led to the development of several pharmacotherapies for retinal vascular diseases such as diabetic macular edema. Many of these agents, in the form of intravitreal injections or sustained delivery devices, have already undergone clinical trial testing for safety and efficacy and many others are currently being similarly evaluated. Some of these agents have proven to be more efficacious than traditional laser therapy, and it is possible that traditional laser therapy for diabetic macular edema may be abandoned altogether in the near future, especially with the introduction of the micropulse laser. However, more research and experience is still needed in order to determine the best treatment agent or combination of therapeutic modalities, as well as the best treatment regimen for a given patient. In this article, we briefly review the major new developments in the field of diabetic macular edema treatment. In addition, we touch on some of the promising forthcoming therapies.

New insights into the pathoanatomy of diabetic macular edema: angiographic patterns and optical coherence tomography

PURPOSE

To describe the pathoanatomy of diabetic macular edema in optical coherence tomography and its correlation with fluorescein angiography patterns.

METHODS

Sixty eyes of 56 patients were analyzed. Diabetic macular edema was classified into typical focal leakage (from microaneurysm), typical diffuse leakage (the capillary plexus), or combined/questionable leakage using fluorescein angiography and retinal thickness profiles. The leakage and pooling patterns in fluorescein angiography were matched to the corresponding optical coherence tomography images and analyzed.

RESULTS

Focal leakage shows swelling predominantly in the outer plexiform layer (OPL). Deeply located microaneurysms directly leak into the loose fiber portion of OPL (Henle layer) through the "fluid conductivity barrier" (synaptic portion of OPL). Diffuse leakage caused swelling predominantly in the inner nuclear layer and secondarily in the OPL. The deep capillary plexus is located between the two "fluid barriers" (inner plexiform layer and OPL); thus, diffuse leakage is primarily related with swelling in the inner nuclear layer. In the combined/questionable leakage, partial sections consisting of inner nuclear layer swelling and much larger areas of OPL/outer nuclear layer swelling are noticed.

CONCLUSION

Based on the concept of the fluid conductivity barrier, we revealed a correlation between the intraretinal location of the leakage source and where the fluid accumulated within the retinal layers.

Oral minocycline for the treatment of diabetic macular edema (DME): results of a phase I/II clinical study

PURPOSE

Inflammation contributes significantly to the pathogenesis of diabetic macular edema (DME). In particular, retinal microglia demonstrate increased activation and aggregation in areas of DME. Study authors investigated the safety and potential efficacy of oral minocycline, a drug capable of inhibiting microglial activation, in the treatment of DME.

METHODS

A single-center, prospective, open-label phase I/II clinical trial enrolled five participants with fovea-involving DME who received oral minocycline 100 mg twice daily for 6 months. Main outcome measurements included best-corrected visual acuity (BCVA), central retinal subfield thickness (CST), and central macular volume using spectral domain optical coherence tomography (SD-OCT) and late leakage on fluorescein angiography (FA).

RESULTS

Findings indicated that the study drug was well tolerated and not associated with significant safety issues. In study eyes, mean BCVA improved continuously from baseline at 1, 2, 4, and 6 months by +1.0, +4.0, +4.0, and +5.8 letters, respectively, while mean retinal thickness (CST) on OCT decreased by -2.9%, -5.7%, -13.9, and -8.1% for the same time points. At month 6, mean area of late leakage on FA decreased by -34.4% in study eyes. Mean changes in contralateral fellow eyes also demonstrated similar trends. Improvements in outcome measures were not correlated with concurrent changes in systemic factors.

CONCLUSIONS

In this pilot proof-of-concept study of DME, minocycline as primary treatment was associated with improved visual function, central macular edema, and vascular leakage, comparing favorably with historical controls from previous studies. Microglial inhibition with oral minocycline may be a promising therapeutic strategy targeting the inflammatory etiology of DME. (ClinicalTrials.gov number, NCT01120899.).

New approaches for the treatment of diabetic macular oedema: recommendations by an expert panel

The current standard therapy for patients with diabetic macular oedema (DME)--focal/grid laser photocoagulation--usually does not improve impaired vision, and many patients lose vision despite laser therapy. Recent approval of ranibizumab by the European Medicines Agency to treat visual impairment due to DME fulfils the previously unmet medical need for a treatment that can improve visual acuity (VA) in these patients. We reviewed 1- and 2-year clinical trial findings for ranibizumab used as treatment for DME to formulate evidence-based treatment recommendations in the context of this new therapy. DME with or without visual impairment should be considered for treatment when it fulfils the Early Treatment Diabetic Retinopathy Study (ETDRS) criteria for clinically significant oedema. For DME with centre involvement and associated vision loss due to DME, monthly ranibizumab monotherapy with treatment interruption and re-initiation based on VA stability is recommended. Laser therapy based on ETDRS guidelines is recommended for other forms of clinically significant DME without centre involvement or when no vision loss has occurred, despite centre involvement. Because these recommendations are based on randomised controlled trials of 1-2 years duration, guidance may need updating as long-term ranibizumab data become available and as additional therapeutic agents are assessed in clinical trials.

Clinical development of new treatments for diabetic macular oedema

The benchmark treatment for diabetic macular oedema, the major cause of visual impairment in patients with diabetes mellitus, has traditionally been laser photocoagulation; however, as laser treatment does not always improve vision or even prevent further loss in many cases, several new pharmacotherapies that are injected into the vitreous for diabetic macular oedema have been successfully trialled over the past decade. Others are currently being evaluated. The two major classes of these drugs are steroids and vascular endothelial growth factor antagonists. In this article we briefly review the major clinical studies recently conducted in this field.

Relationship between fluorescein pooling and optical coherence tomographic reflectivity of cystoid spaces in diabetic macular edema

OBJECTIVE

To study the characteristics of the reflectivity of the cystoid spaces and serous retinal detachment (SRD) on spectral-domain optical coherence tomography (SD-OCT) and the correlation with fluorescein findings in diabetic macular edema (DME).

DESIGN

Retrospective, observational, cross-sectional study.

PARTICIPANTS

Consecutive 134 eyes of 114 patients with clinically significant macular edema for whom SD-OCT and fluorescein angiography (FA) were performed on the same day.

METHODS

Fluorescein angiography using Heidelberg Retina Angiograph 2 (Heidelberg Engineering, Heidelberg, Germany) and OCT images using Spectralis OCT (Heidelberg Engineering) were obtained. The reflectivity of the cystoid spaces and SRD on the OCT images was evaluated qualitatively and quantitatively and compared with the fluorescein pooling intensity on FA images.

MAIN OUTCOME MEASURES

The relationship between the fluorescein pooling and the reflectivity characteristics of the cystoid spaces on SD-OCT images.

RESULTS

A total of 141 cystoid spaces in 101 eyes were delineated on OCT images, and 138 spaces (97.9%) had fluorescein pooling. Fifty-five cystoid spaces (39.9%) with marked fluorescein pooling intensity had lower reflectivity on OCT images than those with modest pooling (12.1±10.4 vs. 22.0±15.4, P < 0.001). The heterogeneity of the reflectivity of the cystoid spaces on the OCT images was associated significantly (P < 0.001) with modest fluorescein pooling. The hyperreflective foci in the cystoid spaces were correlated significantly with modest fluorescein pooling and higher or heterogeneous reflectivity on OCT images (P < 0.001, P < 0.001, and P=0.005, respectively). In addition, the cystoid spaces with microaneurysms had higher or heterogeneous reflectivity on OCT images more frequently than those without microaneurysms (P < 0.001 and P=0.019, respectively). The reflectivity levels in the SRD were significantly (P=0.005) lower than in the cystoid spaces, and only 1 eye (3.3%) had heterogeneous reflectivity on OCT images.

CONCLUSIONS

The results provided a novel interpretation of fluorescein pooling and OCT characteristics of cystoid spaces and SRD in DME and suggested several mechanisms by which the blood-retinal barrier is disrupted and concomitant edematous changes develop.

The expanding role of vascular endothelial growth factor inhibitors in ophthalmology

Vascular endothelial growth factor (VEGF) plays an important role in both physiologic and pathologic angiogenesis and contributes to increased permeability across both the blood-retinal and blood-brain barriers. After 2 decades of extensive research into the VEGF families and receptors, specific molecules have been targeted for drug development, and several medications have received US Food and Drug Administration approval. Bevacizumab, a full-length antibody against VEGF approved for the intravenous treatment of advanced carcinomas, has been used extensively in ophthalmology for exudative age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, retinopathy of prematurity, and other chorioretinal vascular disorders. Pegaptanib and ranibizumab have been developed specifically for intraocular use, whereas the soon-to-be-introduced aflibercept (VEGF Trap-Eye) is moving through clinical trials for both intraocular and systemic use. Although these drugs exhibit excellent safety profiles, ocular and systemic complications, particularly thromboembolic events, remain a concern in patients receiving therapy. Patients experiencing adverse events that may be related to VEGF suppression should be carefully evaluated by both the ophthalmologist and the medical physician to reassess the need for intraocular therapy and explore the feasibility of changing medications. For this review a search of PubMed from January 1, 1985 through April 15, 2011, was performed using the following terms (or combination of terms): vascular endothelial growth factors, VEGF, age-related macular degeneration, diabetic retinopathy, retina vein occlusions, retinopathy of prematurity, intravitreal injections, bevacizumab, ranibizumab, and VEGF Trap. Studies were limited to those published in English. Other articles were identified from bibliographies of retrieved articles and archives of the author.

Dexamethasone intravitreal implant for treatment of diabetic macular edema in vitrectomized patients

PURPOSE

To evaluate the safety and efficacy of Ozurdex (dexamethasone intravitreal implant) 0.7 mg in the treatment of diabetic macular edema in vitrectomized eyes.

METHODS

This was a prospective, multicenter, open-label, 26-week study. Fifty-five patients with treatment-resistant diabetic macular edema and a history of previous pars plana vitrectomy in the study eye received a single intravitreal injection of 0.7-mg dexamethasone intravitreal implant. The primary efficacy outcome measure was the change in central retinal thickness from baseline to Week 26 measured by optical coherence tomography.

RESULTS

The mean age of patients was 62 years. The mean duration of diabetic macular edema was 43 months. The mean (95% confidence interval) change from baseline central retinal thickness (403 μm) was -156 μm (-190, -122 μm) at Week 8 (P < 0.001) and -39 μm (-65, -13 μm) at Week 26 (P = 0.004). The mean (95% CI) increase in best-corrected visual acuity from baseline (54.5 letters) was 6.0 letters (3.9, 8.1 letters) at Week 8 (P < 0.001) and 3.0 letters (0.1, 6.0 letters) at Week 26 (P = 0.046). At Week 8, 30.4% of patients had gained ≥10 letters in best-corrected visual acuity. Conjunctival hemorrhage, conjunctival hyperemia, eye pain, and increased intraocular pressure were the most common adverse events.

CONCLUSION

Treatment with dexamethasone intravitreal implant led to statistically and clinically significant improvements in both vision and vascular leakage from diabetic macular edema in difficult-to-treat vitrectomized eyes and had an acceptable safety profile.

Intravitreal injection of commercially available ketorolac tromethamine in eyes with diabetic macular edema refractory to laser photocoagulation

PURPOSE

To evaluate the short-term effect of a single intravitreal injection of commercially available ketorolac tromethamine (KT) in eyes with diabetic macular edema refractory to laser photocoagulation.

METHODS

Prospective interventional case series. Twenty five patients with diabetic macular edema refractory to laser photocoagulation received a single intravitreal injection of commercially available KT (Toradol®), in a dose of 3000 µg. Examination included assessment of ETDRS-best corrected visual acuity (BCVA), measurement of intraocular pressure and high resolution imaging by optical coherence tomography, preoperatively and 7, 15, and 30 days postoperatively.

RESULTS

In the follow up visits at 7, 15 and 30 days, BCVA had improved five or more letters in 20% (95% confidence interval, 7.7-38.9%), 16% (95% confidence interval, 5.3-34.2%) and 28% (95% confidence interval, 13.2-47.7%) respectively. An improvement in macular thickness was also observed, although it has not been statistically significant.

CONCLUSION

This pilot study showed that a single intravitreal injection of 3000 µg of commercial KT led to a short-term improvement of visual acuity in approximately 30% of eyes with diabetic macular edema refractory to laser photocoagulation.

Pericyte-derived sphingosine 1-phosphate induces the expression of adhesion proteins and modulates the retinal endothelial cell barrier

OBJECTIVE

The mechanisms that regulate the physical interaction of pericytes and endothelial cells and the effects of these interactions on interendothelial cell junctions are not well understood. We determined the extent to which vascular pericytes could regulate pericyte-endothelial adhesion and the consequences that this disruption might have on the function of the endothelial barrier.

METHODS AND RESULTS

Human retinal microvascular endothelial cells were cocultured with pericytes, and the effect on the monolayer resistance of endothelial cells and expression of the cell junction molecules N-cadherin and VE-cadherin were measured. The molecules responsible for the effect of pericytes or pericyte-conditioned media on the endothelial resistance and cell junction molecules were further analyzed. Our results indicate that pericytes increase the barrier properties of endothelial cell monolayers. This barrier function is maintained through the secretion of pericyte-derived sphingosine 1-phosphate. Sphingosine 1-phosphate aids in maintenance of microvascular stability by upregulating the expression of N-cadherin and VE-cadherin, and downregulating the expression of angiopoietin 2.

CONCLUSIONS

Under normal circumstances, the retinal vascular pericytes maintain pericyte-endothelial contacts and vascular barrier function through the secretion of sphingosine 1-phosphate. Alteration of pericyte-derived sphingosine 1-phosphate production may be an important mechanism in the development of diseases characterized by vascular dysfunction and increased permeability.

New approaches to the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is a leading cause of visual impairment in working age in industrialized countries. It is classified as non-proliferative (mild, moderate or severe) and proliferative, with diabetic macular oedema potentially developing at any of these stages. The prevalence and incidence of DR increase with diabetes duration and worsening of metabolic and blood pressure control. Current approaches to prevent and/or treat DR include optimized control of blood glucose and blood pressure and screening for early identification of high-risk, although still asymptomatic, retinal lesions. Results from recent clinical trials suggest a role for blockers of the renin-angiotensin system (angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers) and for fenofibrate in reducing progression and/or inducing regression of mild-to-moderate non-proliferative DR. Intravitreal administration of anti-vascular endothelial growth factor (VEGF) agents was shown to reduce visual loss in more advanced stages of DR, especially in macular oedema.

A potential role for angiopoietin 2 in the regulation of the blood-retinal barrier in diabetic retinopathy

PURPOSE

Although VEGF has been identified as an important mediator of the blood-retinal barrier alteration in diabetic retinopathy, the hypothesis for this study was that that other molecules, including the angiopoietins (Ang-1 and -2), may play a role. The expression of angiopoietins was analyzed in an animal model of diabetic retinopathy, and the role of Ang-2 in the regulation of diabetes-induced alterations of vascular permeability was characterized.

METHODS

Diabetes was induced in rats, and human retinal endothelial cells (HRECs) were grown in media with 5.5 or 30.5 mM glucose. Levels of Ang-1 and -2 mRNA and protein were analyzed. Fluorescence-based assays were used to assess the effect of Ang-2 on vascular permeability in vivo and in vitro. The effect of Ang-2 on VE-cadherin function was assessed by measuring the extent of tyrosine phosphorylation.

RESULTS

Ang-2 mRNA and protein increased in the retinal tissues after 8 weeks of diabetes and in high-glucose-treated cells. Intravitreal injection of Ang-2 in rats produced a significant increase in retinal vascular permeability. Ang-2 increased HREC monolayer permeability that was associated with a decrease in VE-cadherin and a change in monolayer morphology. High glucose and Ang-2 produced a significant increase in VE-cadherin phosphorylation. CONCLUSIONS; Ang-2 is upregulated in the retina in an animal model of diabetes, and hyperglycemia induces the expression of Ang-2 in isolated retinal endothelial cells. Increased Ang-2 alters VE-cadherin function, leading to increased vascular permeability. Thus, Ang-2 may play an important role in increased vasopermeability in diabetic retinopathy.

A phase 2/3, multicenter, randomized, double-masked, 2-year trial of pegaptanib sodium for the treatment of diabetic macular edema

PURPOSE

To confirm the safety and compare the efficacy of intravitreal pegaptanib sodium 0.3 mg versus sham injections in subjects with diabetic macular edema (DME) involving the center of the macula associated with vision loss not due to ischemia.

DESIGN

Randomized (1:1), sham-controlled, multicenter, parallel-group trial.

PARTICIPANTS

Subjects with DME.

INTERVENTION

Subjects received pegaptanib 0.3 mg or sham injections every 6 weeks in year 1 (total = 9 injections) and could receive focal/grid photocoagulation beginning at week 18. During year 2, subjects received injections as often as every 6 weeks per prespecified criteria.

MAIN OUTCOME MEASURES

The primary efficacy endpoint was the proportion gaining ≥ 10 letters of visual acuity (VA) from baseline to year 1. Safety was monitored throughout.

RESULTS

In all, 260 (pegaptanib, n = 133; sham, n = 127) and 207 (pegaptanib, n = 107; sham, n = 100) subjects were included in years 1 and 2 intent-to-treat analyses, respectively. A total of 49 of the 133 (36.8%) subjects from the pegaptanib group and 25 of the 127 (19.7%) from the sham group experienced a VA improvement of ≥ 10 letters at week 54 compared with baseline (odds ratio [OR], 2.38; 95% confidence interval, 1.32-4.30; P = 0.0047). For pegaptanib-treated subjects, change in mean VA from baseline by visit was superior (P<0.05) to sham at weeks 6, 24, 30, 36, 42, 54, 78, 84, 90, 96, and 102. At week 102, pegaptanib-treated subjects gained, on average, 6.1 letters versus 1.3 letters for sham (P<0.01). Fewer pegaptanib- than sham-treated subjects received focal/grid laser treatment (week 54, 31/133 [23.3%] vs 53/127 [41.7%], respectively, P = 0.002; week 102, 27/107 [25.2%] vs 45/100 [45.0%], respectively, P = 0.003). The pegaptanib treatment group showed significantly better results on the National Eye Institute-Visual Functioning Questionnaire than sham for subscales important in this population. Pegaptanib was well tolerated; the frequencies of discontinuations, adverse events, treatment-related adverse events, and serious adverse events were comparable in the pegaptanib and sham groups.

CONCLUSIONS

Patients with DME derive clinical benefit from treatment with the selective vascular endothelial growth factor antagonist pegaptanib 0.3 mg. These findings indicate that intravitreal pegaptanib is effective in the treatment of DME and, taken together with prior study data, support a positive safety profile in this population.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Diagnosis and detection

PURPOSE

To evaluate features of macular edema assessed by optical coherence tomography (OCT)and other imaging tools such as infrared, blue retinography and autofluorescence, and fluorescein and indocyanine green angiography (ICGA) in different pathologic conditions.

METHODS

The principal causes of macular edema were reviewed to evaluate its aspect in each pathology. Correlations between OCT and other imaging techniques were analyzed.

RESULTS

Optical coherence tomography and other imaging tools allowed the authors to confirm the existence of different macular edema patterns for different pathologies and to describe their characteristics; in particular, some conditions, like idiopathic macular telangiectasias and age-related maculopathy, were found to present specific edema patterns.

CONCLUSIONS

Simultaneous use of different imaging techniques allowed a better evaluation and follow-up of conditions causing cystoid macular edema.

Macular perfusion determined by fundus fluorescein angiography at the 4-month time point in a prospective randomized trial of intravitreal bevacizumab or laser therapy in the management of diabetic macular edema (Bolt Study): Report 1

PURPOSE

The purpose of this study was to assess macular perfusion with fundus fluorescein angiography at the 4-month time point in a prospective randomized, single-center 2-year trial comparing intravitreal bevacizumab and laser therapy in patients with diabetic macular edema.

METHODS

All enrolled patients had standard Early Treatment of Diabetic Retinopathy Study 7-field fundus photographs and fundus fluorescein angiography at baseline and subsequently at 4-month intervals. Patients were excluded from the study if either the greatest linear dimension of the foveal avascular zone (FAZ) was >1,000 microm in diameter or there was severe perifoveal capillary loss (Early Treatment of Diabetic Retinopathy Study criteria) on fundus fluorescein angiography. The fundus fluorescein angiograms of the bevacizumab (n=42) and laser (n=38) groups were graded for greatest linear dimension of the FAZ, area of the FAZ, and perifoveal capillary loss by the Moorfields Reading Centre in a masked fashion.

RESULTS

At baseline, the mean greatest linear dimension of the FAZ in the laser group was 685 +/- 262 microm and in the bevacizumab group was 737 +/- 262 microm. There was no significant difference at the 4-month time point (P 0.40) with the mean greatest linear dimension of the FAZ in the laser group recorded as 678 +/- 221 microm and in the bevacizumab group was 678 +/- 231 microm. At baseline, the median area of the FAZ in the laser group was 0.36 mm(2) (interquartile range, 0.21-0.46) and in the bevacizumab group was 0.33 mm(2) (interquartile range, 0.27-0.49). There was no significant difference at the 4-month time point (P=0.30) with the median area of the FAZ in the laser group recorded as 0.35 mm(2) (interquartile range, 0.20-0.52) and in the bevacizumab group was 0.34 mm(2) (interquartile range, 0.23-0.47). Similarly, there was no difference between the two treatment groups (P=0.64) when a comparison was made of the number of grades of change in perifoveal capillary loss observed in each patient. To date, no patients have been withdrawn from the study because of worsening macular ischemia.

CONCLUSION

At 4 months, there was no evidence of worsening macular ischemia in either group.

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.

Ranibizumab for diabetic macular edema difficult to treat with focal/grid laser

BACKGROUND

To evaluate the efficacy of intravitreal injections of ranibizumab in patients with diabetic clinically significant macular edema (CSME), when further focal or grid laser was considered to be unsafe.

METHODS

In this retrospective, interventional case study, intravitreal injections of ranibizumab were performed in 16 eyes (ten patients) suffering from diabetic retinopathy with CSME. All patients had been treated in the past with focal or grid laser. Additional photocoagulation could not be performed because the leaking points were very close to the avascular zone, and there was also a perifoveal capillary dropout. The patients underwent three injections (months 0, 1 and 2) and were followed monthly. Reinjection was performed if central retinal thickness (CRT) was ≥250 μm associated with fluorescein leakage involving the center of the macula.

RESULTS

The patients underwent a median of seven injections (range 6-9) and the median follow-up time was 11 months (range 9-15). The median best-corrected visual acuity (BCVA) was 0.85 logMAR at baseline and 0.54 logMAR at the end of the follow-up time (p = 0.018). BCVA improved in seven eyes (43.75%), remained stable in eight (50%) and decreased in one eye (6.25%). The median CRT decreased from 409.5 μm at baseline to 272 μm at the end of the follow-up time (p = 0.0002). No ocular or systemic adverse events were reported.

CONCLUSIONS

For a median follow-up time of 11 months, the treatment with intravitreal injections of ranibizumab resulted in stabilization or improvement of the visual acuity in the vast majority of patients with diabetic maculopathy and CSME, when further focal or grid laser was considered to be unsafe.

Vitreous traction and epiretinal membranes in diabetic macular oedema using spectral-domain optical coherence tomography

PURPOSE

The purpose of this study was to present an association between diabetic macular oedema (DME) and vitreoretinal interface abnormalities using 3D spectral domain optical coherence tomography (SD-OCT).

METHODS

In a retrospective study, charts and SD-OCT of consecutive patients with diffuse or focal DME were reviewed. Only one randomly chosen eye per patient with DME was included, and eyes that had another retinopathy that could affect the study analysis or that underwent vitreoretinal surgery were excluded.

RESULTS

Out of 58 eyes (58 patients) with DME, 11 eyes (19.0%) had vitreofoveal traction (Group A), either unifocally (n=6) or multifocally; that is, associated with additional extrafoveal traction site(s). Group B comprised 20 eyes (34.5%) that had sole extrafoveal vitreous traction, at either retinal and/or papillary sites. In each, the retinal oedema underlying extrafoveal traction was in continuum in at least one site with that at the central macula, as verified by the macular maps, thus presented as diffuse macular oedema. In Group C, 13 eyes (22.4%) had an epiretinal membrane (ERM), 1.5 × 3 mm to ≥6 × 6 mm in size that overlaid diffuse oedematous macula. Group D included 14 eyes (24.1%) that had neither vitreous traction nor ERM; 12 (20.7%) of them had DME secondary to leaking microaneurysms with or without leaking capillary beds, and the remaining two had leakage from non-microaneurysms sources.

CONCLUSIONS

DME was detected by the SD-OCT to be associated with sole extrafoveal vitreous traction in one-third of the patients. Further studies are required to evaluate the clinical consequences of these observations.

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.

Pycnogenol improves microcirculation, retinal edema, and visual acuity in early diabetic retinopathy

PURPOSE

The growing numbers of diabetes cases in the developed world are followed by increasing numbers of people diagnosed with diabetic complications. Diabetic microangiopathies in the eye lead to the development of retinopathy involving gradual loss of vision. Previous studies with Pycnogenol showed effectiveness for stopping progression of preproliferative stages of retinopathy. The aim of our study was to show protective effects of Pycnogenol in early stages of retinopathy, characterized by mild to moderate retinal edema in the absence of hemorrhages or hard exudates in the macula center.

METHODS

Following treatment with Pycnogenol (24 patients) for 3 months, retinal edema score (dilated ophthalmology) and retinal thickness (high resolution ultrasound) showed statistically significant improvement as compared to the placebo group (22 patients), which showed negligible changes to baseline. Laser Doppler flow velocity measurements at the central retinal artery showed a statistically significant increase from 34 to 44 cm/s in the Pycnogenol group as compared to marginal effects in the control group.

RESULTS

The major positive observation of this study is the visual improvement, which was subjectively perceived by 18 out of 24 patients in the Pycnogenol group. Testing of visual acuity using the Snellen chart showed a significant improvement from baseline 14/20 to 17/20 already, after 2 months treatment, whereas no change was found in the control group.

CONCLUSIONS

Pycnogenol taken at this early stage of retinopathy may enhance retinal blood circulation accompanied by regression of edema, which favorably improves vision of patients.

Cataract surgery and diabetes

PURPOSE OF REVIEW

Recent studies have focused on interventions to minimize progression of retinal disease in diabetic patients undergoing cataract surgery. Here, we review the evidence for progression of diabetic retinal disease with cataract surgery and critically analyze the interventions proposed to minimize it.

RECENT FINDINGS

Peri-operative intravitreal bevacizumab, sub-Tenon's triamcinolone, and panretinal photocoagulation (PRP) after cataract surgery (instead of before) have been examined as ways to improve cataract surgery results in diabetic patients. The bevacizumab and triamcinolone results are promising, but the inclusion criteria are variable, the sample sizes are small, and the follow-up is short. Postsurgery PRP shows improved cataract surgery results in diabetics with more severe retinopathy up to 1 year after surgery.

SUMMARY

Recent studies do not support the generalized conclusion that phacoemulsification surgery causes progression of retinopathy and macular edema in all diabetic patients. In certain populations of diabetic patients undergoing cataract surgery, peri-operative triamcinolone and bevacizumab may blunt the progression of diabetic macular edema and diabetic retinopathy. The optimal timing of PRP in relation to cataract surgery in patients with more severe retinopathy warrants further evaluation.

Effect of retinal photocoagulation on intraretinal lipid exudates in diabetic macular edema documented by optical coherence tomography

PURPOSE

To study the changes in the distribution and morphologic features of intraretinal microexudates after macular photocoagulation.

DESIGN

Prospective cohort study.

PARTICIPANTS

Thirteen treatment-naïve patients with clinically significant macular edema in type 2 diabetes.

METHODS

Patients were treated with focal macular photocoagulation. Changes in the localization of hyperreflective foci were analyzed by spectral domain (SD) optical coherence tomography (OCT) during follow-up at day 1, week 1, and months 1, 2, 3, and 4 in defined areas. Further, fundus photography and infrared imaging were performed at all visits and findings were correlated to OCT results.

MAIN OUTCOME MEASURES

Changes in retinal morphologic features detected in OCT.

RESULTS

A dynamic change in the distribution pattern of hyperreflective foci was observed over 4 months after the photocoagulation. With the decrease of retinal thickness, the dots either resolved completely or became confluent at the apical border of the outer nuclear layer, and finally formed ophthalmoscopically detectable hard exudates during extended follow-up. In the event of retinal thickening despite laser treatment, the hyperreflective dots maintained their previous distribution throughout all retinal layers. As a fourth response, dissemination of plaques of hard exudates into multiple, separate, hyperreflective foci were detected.

CONCLUSIONS

Hyperreflective foci in the retina seem to represent precursors or components of hard exudates. Their specific localization depends greatly on the presence of microvascular extravasation and intraretinal fluid accumulation. Retinal photocoagulation has a major impact on retinal edema and subsequently on the distribution of intraretinal lipid deposits.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.