Combined treatment modalities for age related macular degeneration

Application of Porphyrins in Antibacterial Photodynamic Therapy

Antibiotics are commonly used to control, treat, or prevent bacterial infections, however bacterial resistance to all known classes of traditional antibiotics has greatly increased in the past years especially in hospitals rendering certain therapies ineffective. To limit this emerging public health problem, there is a need to develop non-incursive, non-toxic, and new antimicrobial techniques that act more effectively and quicker than the current antibiotics. One of these effective techniques is antibacterial photodynamic therapy (aPDT). This review focuses on the application of porphyrins in the photo-inactivation of bacteria. Mechanisms of bacterial resistance and some of the current 'greener' methods of synthesis of meso-phenyl porphyrins are discussed. In addition, significance and limitations of aPDT are also discussed. Furthermore, we also elaborate on the current clinical applications and the future perspectives and directions of this non-antibiotic therapeutic strategy in combating infectious diseases.

Widening use of dexamethasone implant for the treatment of macular edema

Sustained-release intravitreal 0.7 mg dexamethasone (DEX) implant is approved in Europe for the treatment of macular edema related to diabetic retinopathy, branch retinal vein occlusion, central retinal vein occlusion, and non-infectious uveitis. The implant is formulated in a biodegradable copolymer to release the active ingredient within the vitreous chamber for up to 6 months after an intravitreal injection, allowing a prolonged interval of efficacy between injections with a good safety profile. Various other ocular pathologies with inflammatory etiopathogeneses associated with macular edema have been treated by DEX implant, including neovascular age-related macular degeneration, Irvine-Gass syndrome, vasoproliferative retinal tumors, retinal telangiectasia, Coats' disease, radiation maculopathy, retinitis pigmentosa, and macular edema secondary to scleral buckling and pars plana vitrectomy. We undertook a review to provide a comprehensive collection of all of the diseases that benefit from the use of the sustained-release DEX implant, alone or in combination with concomitant therapies. A MEDLINE search revealed lack of randomized controlled trials related to these indications. Therefore we included and analyzed all available studies (retrospective and prospective, comparative and non-comparative, randomized and nonrandomized, single center and multicenter, and case report). There are reports in the literature of the use of DEX implant across a range of macular edema-related pathologies, with their clinical experience supporting the use of DEX implant on a case-by-case basis with the aim of improving patient outcomes in many macular pathologies. As many of the reported macular pathologies are difficult to treat, a new treatment option that has a beneficial influence on the clinical course of the disease may be useful in clinical practice.

Dexamethasone Intravitreal Implant as Adjunctive Therapy to Ranibizumab in Neovascular Age-Related Macular Degeneration: A Multicenter Randomized Controlled Trial

Purpose: To evaluate the efficacy and safety of dexamethasone intravitreal implant 0.7 mg (DEX) as adjunctive therapy to ranibizumab in neovascular age-related macular degeneration (nvAMD). Procedures: This was a 6-month, single-masked, multicenter study. Patients were randomized to DEX implant (n = 123) or sham procedure (n = 120) and received 2 protocol-mandated intravitreal ranibizumab injections. The main outcome measure was injection-free interval to first as-needed ranibizumab injection. Results: DEX increased the injection-free interval versus sham (50th percentile, 34 vs. 29 days; 75th percentile, 85 vs. 56 days; p = 0.016). 8.3% of DEX versus 2.5% of sham-treated patients did not require rescue ranibizumab (p = 0.048). Visual acuity and retinal thickness outcomes were similar in DEX and sham-treated patients. Only reports of conjunctival hemorrhage (18.2 vs. 8.5%) and intraocular pressure elevation (13.2 vs. 4.2%) were significantly different in the DEX versus the sham treatment groups. Conclusion: DEX reduced the need for adjunctive ranibizumab treatment and showed acceptable tolerability in nvAMD patients.

A prospective study on different methods for the treatment of choroidal neovascularization. The efficacy of verteporfin photodynamic therapy, intravitreal bevacizumab and transpupillary thermotherapy in patients with neovascular age-related macular degeneration

Background

The aim of this study was to compare the efficacy of verteporfin photodynamic therapy (PDT), intravitreal injections of bevacizumab (IVB) and transpupillary thermotherapy (TTT) in patients with neovascular age-related macular degeneration (AMD).

Material/Methods

The study design was a prospective, interventional, comparative case series. Between December 2006 and March 2009, 426 eyes of 426 consecutive patients presenting with neovascular AMD were included into the study. Patients presented with subfoveal CNV predominantly classic, minimally classic, and occult with no classic component; lesion size less than 5000 μm in the greatest linear dimension, and the area of hemorrhages ≤1/3 were randomized to receive either PDT (group I) or IVB (group II) in a 1:1 ratio. Other patients with CNV were included into the group III and received TTT.

Results

One hundred eyes were treated with PDT. Mean baseline logMAR BCVA was 0.62 and final visual acuity decreased to 0.74 (p<0.05, Wilcoxon test); 104 eyes were treated with IVB. Mean baseline BCVA was 0.82 and final visual acuity increased to 0.79 (p>0.05, Wilcoxon test); 222 patients were treated with TTT. Mean baseline BCVA was 1.10 and final visual acuity decreased to 1.15 (p>0.05, Wilcoxon test). Among all eyes the average number of treatment sessions was 2.34 (SD 1.17).

Conclusions

Our study shows that IVB injections had the best efficacy in the improvement of final BCVA. However, both IVB and TTT demonstrated good stabilization of vision. Although after PDT final BCVA was significantly worse from baseline, it may also be beneficial for some patients with neovascular age-related macular degeneration.