Fundus autofluorescence imaging: Fundamentals and clinical relevance.

Fundus autofluorescence (FAF), a relatively new imaging modality, focuses on the fluorescent properties of pigments in the retina to generate images that help us view various disease processes from a different perspective. It aids us in the understanding of the pathophysiology of different retinal disorders. Recently, FAF imaging is being used commonly to help us in the diagnosis, prognosis as well as in determining the treatment response of various retinal disorders. It generates an image based on the distribution pattern of a fluorescent pigment called lipofuscin. Knowing the distribution pattern of lipofuscin in the normal retina is key to understanding an FAF image representing a retinal pathology. Like most other imaging modalities, FAF comes with its own limitations, taking steps to overcome these limitations will be of utmost importance in using this imaging modality to its fullest potential.

Comparison of time domain and spectral domain optical coherence tomography in measurement of macular thickness in macular edema secondary to diabetic retinopathy and retinal vein occlusion.

Purpose. To evaluate macular thickness, agreement, and intraclass repeatability in three optical coherence tomography (OCT) devices: the time domain (TD) Stratus OCT and two spectral domain (SD) OCTs, Spectralis and Cirrus SD-OCT, in eyes with macular edema secondary to diabetic retinopathy (DR) and retinal vein occlusion (VO). Methods. In a prospective observational study at a university-based retina practice, retinal thickness tomography was performed simultaneously for fifty-eight patients (91 eyes) with DR and VO employing a time domain and two spectral domain OCTs. Agreement in macular measurements was assessed by constructing Bland-Altman plots. Intraclass repeatability was assessed by intraclass correlation coefficients (ICCs). Results. Based on the Bland-Altman plots for central macular thickness, there was low agreement between the measurements of Cirrus SD-OCT and Stratus OCT, Spectralis OCT and Stratus OCT, as well as Spectralis OCT and Cirrus SD-OCT among DR and RVO patients. All three devices demonstrated high intraclass repeatability, with ICC of 98% for Stratus OCT, 97% for Cirrus SD-OCT, and 100% for Spectralis OCT among DR patients. The ICC was 97% for Stratus OCT, 79% for Cirrus SD-OCT, and 91% for Spectralis OCT among RVO patients. Conclusion. There are low agreements among interdevice measurements. However, intraclass repeatability is high in both TD and SD-OCT devices.

The role of biologic agents in the management of non-infectious uveitis.

INTRODUCTION: Uveitis is an intriguing group of disorders characterized by inflammation of the uveal tract. Due to the potential grave consequences of the disease process, it is important to assess the various therapeutic options available for treating uveitis, and their outcomes. AREAS COVERED: This review discusses the use of conventional agents in the management of uveitis, including discussion of the molecular and clinical properties of corticosteroids, antimetabolites, calcineurin inhibitors and alkylating agents and their side effects. In addition, it also discusses the molecular and clinical properties of novel biologic agents and their side effects. Moreover, recommendations as to when biologic agents should be employed are also discussed. EXPERT OPINION: We recommend that in general (except in selected cases of Adamantiades-Behçet's disease) biologics should not be used as a first-line therapy for uveitis due to inconvenience, high cost, and potential immunosuppressive effects. However, many biologics are potent in inducing drug-free remission of uveitis and may be employed to manage recurrent diseases or diseases not responsive to conventional agents.

New treatment options for noninfectious uveitis.

Autoimmune uveitis is a group of sight-threatening inflammatory diseases associated with an exacerbated immunological response to ocular proteins. The Standardization of Uveitis Nomenclature Working Group Guidelines have recommended the use of corticosteroids as the first line of therapy for patients who present with active uveitis. However, long-term use of corticosteroids is associated with numerous adverse effects including cataract, glaucoma and metabolic disorders. In this context, new drugs developed to treat rheumatic diseases, and other autoimmune diseases, are being employed often as monotherapy or combined with other immunosuppressive drugs in order to decrease the corticosteroid burden on patients and to manage refractive uveitis. These drugs are currently being evaluated in the framework of uveitis and may open a new horizon with less side effects and more responsiveness for chronic cases. Among others, calcineurin inhibitor voclosporin, mammalian target of rapamycin inhibitor sirolimus, and the IL-1 trap rilonacept, are among these new agents and will be scrutinized in detail in this chapter. More efficient modes of drug delivery are also being employed to deliver high concentration of drug locally and to minimize systemic side effects. The new modes of drug delivery that we will describe in the index chapter include nanoparticles and iontophoresis.

Macular sensitivity and fixation patterns in normal eyes and eyes with uveitis with and without macular edema.

PURPOSE: This study aims to investigate the relationship between macular sensitivity and thickness in eyes with uveitic macular edema (UME). DESIGN: This study is a prospective observational case series. METHODS: The setting for this study was clinical practice. The study included 59 (28 with UME, 31 without UME) eyes of 26 patients with uveitis and 19 eyes of 10 normal subjects. The procedure followed was fundus-related perimetry and retinal thickness map with an automated fundus perimetry/tomography system. Main outcome measures included quantification of macular sensitivity, fixation pattern, and relationship between macular sensitivity and thickness. RESULTS: Fixation stability revealed that 56 eyes (93.44%) had stable fixation (>75% within the central 2° of point of fixation); three eyes (6.56%) were relatively unstable (<75% of fixation points located within 2°, >75% located within 4°); and no eye had unstable fixation (<75% of fixation points located within 4°). Evaluation of fixation location revealed that 45 eyes (76.27%) had central fixation location (>50% of fixation point within 0.5 mm of foveal center); seven eyes (11.86%) had peri-central fixation location (25% << 50% within 0.5 mm); and seven eyes (11.86%) had eccentric (<25% of fixation point within 0.5 mm) fixation location. We measured macular sensitivity and corresponding thickness in 1,708 loci of 61 study eyes. Macular sensitivity increased by 0.02 dB (95% confidence interval, 0.00, 0.06) per 1 µm increase in the thickness for the thickness values ≤280 µm. Macular sensitivity decreased by 0.04 dB (95% CI, -0.08, -0.01) per 1 µm increase in the thickness for the thickness values >280 µm. CONCLUSIONS: Perimetry quantification of macular sensitivity and retinal thickness, in association with other factors, may offer novel information regarding the impact of UME on retinal function.

Aflibercept: a Potent Vascular Endothelial Growth Factor Antagonist for Neovascular Age-Related Macular Degeneration and Other Retinal Vascular Diseases.

INTRODUCTION: In the western hemisphere, age-related macular degeneration (AMD) is the leading cause of visual loss in the elderly. Currently approved therapies for AMD include argon laser, photodynamic therapy, and antivascular endothelial growth factor (VEGF) therapy. The index review discusses aflibercept (VEGF Trap-Eye) in the context of current anti-VEGF therapies for neovascular AMD and other retinal vascular diseases. It highlights important differences between VEGF Trap-Eye and currently used anti-VEGF therapies for neovascular AMD; and discusses the efficacy of these treatments utilizing information from landmark clinical trials. METHODS: A systematic search of literature was conducted on PubMed, Science Direct, and Scopus with no limitations of language or years of publication. RESULTS: Preclinical studies have shown that VEGF Trap-Eye binds to VEGF-A with a higher affinity than other anti-VEGF molecules; and that it also binds to placental growth factor (PlGF). In clinical trials, VEGF Trap-Eye has been shown to be as effective in the treatment of neovascular AMD as other anti-VEGF therapies and possibly to have a longer duration of drug activity. CONCLUSION: VEGF Trap-Eye has enhanced the treatment options currently available for the management of neovascular AMD. The comparable efficacy of VEGF Trap-Eye (to other anti-VEGF agents) coupled with its longer dosing interval may decrease the number of annual office visits for patients with AMD and their caregivers.