Frank G. Holz

Fundus autofluorescence imaging: review and perspectives.

Fundus autofluorescence (FAF) imaging is a novel imaging method that allows topographic mapping of lipofuscin distribution in the retinal pigment epithelium cell monolayer as well as of other fluorophores that may occur with disease in the outer retina and the subneurosensory space. Excessive accumulation of lipofuscin granules in the lysosomal compartment of retinal pigment epithelium cells represents a common downstream pathogenetic pathway in various hereditary and complex retinal diseases, including age-related macular degeneration. FAF imaging has been shown to be useful with regard to understanding of pathophysiologic mechanisms, diagnostics, phenotype–genotype correlation, identification of predictive markers for disease progression, and monitoring of novel therapies. FAF imaging gives information above and beyond that obtained by conventional imaging methods, such as fundus photography, fluorescein angiography, and optical coherence tomography. Its clinical value coupled with its simple, efficient, and noninvasive nature is increasingly appreciated. This review summarizes basic principles and FAF findings in various retinal diseases.

Safety and Efficacy of a Flexible Dosing Regimen of Ranibizumab in Neovascular Age-Related Macular Degeneration: The SUSTAIN Study

OBJECTIVE To evaluate the safety and efficacy of individualized ranibizumab treatment in patients with neovascular age-related macular degeneration. DESIGN Twelve-month, phase III, multicenter, open-label, single-arm study. PARTICIPANTS A total of 513 ranibizumab-naïve SUSTAIN patients. INTERVENTION Three initial monthly injections of ranibizumab (0.3 mg) and thereafter pro re nata (PRN) retreatment for 9 months based on prespecified retreatment criteria. Patients switched to 0.5 mg ranibizumab after approval in Europe. MAIN OUTCOME MEASURES Frequency of adverse events (AEs), monthly change of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline, the time to first re-treatment, and the number of treatments were assessed. RESULTS A total of 249 patients (48.5%) reported ocular AEs, and 8 (1.5%) deaths, 5 (1.2%) patients with ocular serious AEs of the study eye (retinal hemorrhage, cataract, retinal pigment epithelial tear, reduced visual acuity [VA], vitreous hemorrhage), and 19 (3.7%) patients with arteriothromboembolic events were observed. Most frequent AEs in the study eye were reduced VA (18.5%), retinal hemorrhage (7.2%), increased intraocular pressure (7.0%), and conjunctival hemorrhage (5.5%). The average number of re-treatments from months 3 to 11 was 2.7. Mean best-corrected visual acuity increased steadily from baseline to month 3 to reach +5.8 letters, decreased slightly from month 3 to 6, and remained stable from month 6 to 12, reaching +3.6 at month 12. Mean change in CRT was -101.1 μm from baseline to month 3 and -91.5 μm from baseline to month 12. CONCLUSIONS The safety results are comparable to the favorable tolerability profile of ranibizumab observed in previous pivotal clinical studies; individualized treatment with less than monthly re-treatments shows a similar safety profile as observed in previous randomized clinical trials with monthly ranibizumab treatment. Efficacy outcomes were achieved with a low average number of re-treatments. Visual acuity in SUSTAIN patients with individualized re-treatment based on VA/optical coherence tomography assessment reached on average a maximum after the first 3 monthly injections, decreased slightly under PRN during the next 2 to 3 months, and was then sustained throughout the treatment period.

Intraocular Pharmacokinetics of Bevacizumab After a Single Intravitreal Injection in Humans

PURPOSE To investigate intraocular concentrations and pharmacokinetics of bevacizumab after a single intravitreal injection in humans. DESIGN Prospective, noncomparative, interventional case series. METHODS We included 30 nonvitrectomized eyes of 30 patients (age range, 43 to 93 years) diagnosed with clinically significant cataract and concurrent macular edema secondary to neovascular age-related macular degeneration, diabetic retinopathy, or retinal venous occlusion in the same eye. All patients received an intravitreal injection of 1.5 mg bevacizumab. Between one and 53 days after injection, an aqueous humor sample was obtained during elective cataract surgery. Concentrations of unbound bevacizumab in these samples were quantified by enzyme-linked immunosorbent assay. RESULTS Concentration of bevacizumab in aqueous humor peaked on the first day after injection with a mean concentration (c(max)) of 33.3 microg/ml (range, 16.6 to 42.5 microg/ml) and subsequently declined in a monoexponential fashion. Nonlinear regression analysis determined an elimination half-time (t(1/2)) of 9.82 days (R(2) = 0.81). No significant differences between diagnosis subgroups were noted. CONCLUSIONS In human nonvitrectomized eyes, the aqueous half-life of 1.5 mg intravitreally injected bevacizumab is 9.82 days.

Ranibizumab (Lucentis) in neovascular age-related macular degeneration: evidence from clinical trials

Background: Neovascular age-related macular degeneration (AMD) has a poor prognosis if left untreated, frequently resulting in legal blindness. Ranibizumab is approved for treating neovascular AMD. However, further guidance is needed to assist ophthalmologists in clinical practice to optimise treatment outcomes. Methods: An international retina expert panel assessed evidence available from prospective, multicentre studies evaluating different ranibizumab treatment schedules (ANCHOR, MARINA, PIER, SAILOR, SUSTAIN and EXCITE) and a literature search to generate evidence-based and consensus recommendations for treatment indication and assessment, retreatment and monitoring. Results: Ranibizumab is indicated for choroidal neovascular lesions with active disease, the clinical parameters of which are outlined. Treatment initiation with three consecutive monthly injections, followed by continued monthly injections, has provided the best visual-acuity outcomes in pivotal clinical trials. If continued monthly injections are not feasible after initiation, a flexible strategy appears viable, with monthly monitoring of lesion activity recommended. Initiation regimens of fewer than three injections have not been assessed. Continuous careful monitoring with flexible retreatment may help avoid vision loss recurring. Standardised biomarkers need to be determined. Conclusion: Evidence-based guidelines will help to optimise treatment outcomes with ranibizumab in neovascular AMD.

Patterns of increased in vivo fundus autofluorescence in the junctional zone of geographic atrophy of the retinal pigment epithelium associated with age-related macular degeneration

Abstract · Purpose: To determine in vivo lipofuscin (LF)-induced topographic variations of fundus autofluorescence in eyes with geographic atrophy (GA) of the retinal pigment epithelium (RPE) associated with age-related macular degeneration (ARMD). · Methods: Fundus autofluorescence was examined with a confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph) after excitation with an argon laser (488 nm) and detection of the emitted light above 500 nm. Fifty-seven eyes of 38 patients with uni- or multifocal GA associated with ARMD were studied. The findings were compared with 43 eyes with GA secondary to other etiologies, including juvenile macular dystrophies. · Results: An increased autofluorescence outside the GA was observed in 47 (82.5%) of 57 eyes with GA associated with ARMD in contrast to 4 (9.3%) of 43 eyes with GA of other causes (P<0.001). Three different patterns were noted: a continuous band at the margin with variable peripheral extension in 36 eyes (76.6%), a diffusely increased autofluorescence at the entire posterior pole in 6 eyes (12.8%), and small focal spots of increased autofluorescence in the junctional zone in 3 eyes (6.4%). Of 19 patients with bilateral GA, 17 (89.5%) had an identical pattern in both eyes. · Conclusions: The different patterns of autofluorescence in the presence of GA associated with ARMD may reflect variable forms of reactive changes in the surrounding RPE cells, and may indicate the extend of compromised RPE secondary to ageing changes in the outer retina, Bruch’s membrane and choriocapillaris. Since GA spreads over time, increased LF accumulation in the junctional zone may precede cell death and may, therefore, be of prognostic value. Knowledge of the topographic variation in LF accumulation is important because heterogeneity may reflect underlying differences in cell kinetics, metabolism and biochemistry.

High-Resolution Spectral Domain-OCT Imaging in Geographic Atrophy Associated with Age-Related Macular Degeneration

PURPOSE To describe morphologic variations in outer retinal layers in eyes with atrophic age-related macular degeneration (AMD) using high-resolution, spectral-domain optical coherence tomography (SD-OCT). METHODS SD-OCT scans were obtained with a combined confocal scanning laser ophthalmoscope (cSLO) and SD-OCT for simultaneous tomographic and topographic in vivo imaging. A total of 81 eyes of 56 patients (mean age, 77.8 +/- 7.4 years) with geographic atrophy (GA) were examined. Morphologic alterations were analyzed and classified in the perilesional zone, at the junction between GA and nonatrophic retina, and in the atrophic area itself. RESULTS In the perilesional zone, distinct morphologic alterations included elevations of the outer retinal layers, thickening, and spikes of the outer hyperreflective band as well as clumps at different neurosensory retinal levels. At the junction, highly variable transitions of the outer retinal layers were present with different degrees of loss of the normal hyperreflective bands. Within the actual GA, hyperreflective clumps at different retinal levels, segmented plaques of the outer band and elevations with variable reflectivity were visualized. CONCLUSIONS SD-OCT imaging in eyes with GA revealed a wide spectrum of morphologic alterations, both in the surrounding retinal tissue and in the atrophic area. These alterations may reflect different disease stages or, alternatively, heterogeneity on a cellular and molecular level. Longitudinal studies using in vivo SD-OCT imaging may allow evaluation of the relevance of these phenotypic changes as potential predictive markers for the progression of disease (i.e., enlargement rates of GA over time) and may be used for monitoring of future therapeutic interventions.

Inhibition of the ATP-driven proton pump in RPE lysosomes by the major lipofuscin fluorophore A2-E may contribute to the pathogenesis of age-related macular degeneration

Lipofuscin accumulation in the retinal pigment epithelium (RPE) is associated with various blinding retinal diseases, including age‐related macular degeneration (AMD). The major lipofuscin fluorophor A2‐E is thought to play an important pathogenetic role. In previous studies A2‐E was shown to severely impair lysosomal function of RPE cells. However, the underlying molecular mechanism remained obscure. Using purified lysosomes from RPE cells we now demonstrate that A2‐E is a potent inhibitor of the ATP‐driven proton pump located in the lysosomal membrane. Such inhibition of proton transport to the lysosomal lumen results in an increase of the lysosomal pH with subsequent inhibition of lysosomal hydrolases. An essential task of the lysosomal apparatus of postmitotic RPE for normal photoreceptor function is phagocytosis and degradation of membranous discs shed from photoreceptor outer segments (POS) and of biomolecules from autophagy. When the lysosomes of cultured RPE cells were experimentally loaded with A2‐E, we observed intracellular accumulation of exogenously added POS with subsequent congestion of the phagocytic process. Moreover, the autophagic sequestration of cytoplasmic material was also markedly reduced after A2‐E loading. These data support the hypothesis that A2‐E‐induced lysosomal dysfunction contributes to the pathogenesis of AMD and other retinal diseases associated with excessive lipofuscin accumulation.

Long-term Benefit of Sustained-Delivery Fluocinolone Acetonide Vitreous Inserts for Diabetic Macular Edema

OBJECTIVE To assess the efficacy and safety of intravitreal inserts releasing 0.2 μg/day (low dose) or 0.5 μg/day (high dose) fluocinolone acetonide (FA) in patients with diabetic macular edema (DME). DESIGN Two parallel, prospective, randomized, sham injection-controlled, double-masked, multicenter clinical trials. PARTICIPANTS Subjects with persistent DME despite at least 1 macular laser treatment were randomized 1:2:2 to sham injection (n = 185), low-dose insert (n = 375), or high-dose insert (n = 393). METHODS Subjects received study drug or sham injection at baseline and after 6 weeks were eligible for rescue laser. Based on retreatment criteria, additional study drug or sham injections could be given after 1 year. MAIN OUTCOME MEASURES The primary outcome was the percentage of patients with improvement from baseline best-corrected visual acuity (BCVA) in Early Treatment Diabetic Retinopathy Trial (ETDRS) letter score of 15 or more at month 24. Secondary outcomes included other parameters of visual function and foveal thickness (FTH). RESULTS The percentage of patients with improvement from baseline ETDRS letter score of 15 or more at month 24 was 28.7 and 28.6 in the low- and high-dose insert groups, respectively, compared with 16.2 in the sham group (P = 0.002 for each). Benefit occurred for both doses compared with sham at 3 weeks and all subsequent time points. The mean improvement in BCVA letter score between baseline and month 24 was 4.4 and 5.4 in the low- and high-dose groups, respectively, compared with 1.7 in the sham group (P = 0.02 and P = 0.016). At all time points compared with sham, there was significantly more improvement in FTH. Subjects requiring cataract surgery were more frequent in the insert groups, and their visual benefit was similar to that of subjects who were pseudophakic at baseline. Glaucoma requiring incisional surgery occurred in 3.7%, 7.6%, and 0.5% of the low-dose, high-dose, and sham groups, respectively. CONCLUSIONS Both low- and high-dose FA inserts significantly improved BCVA in patients with DME over 2 years, and the risk-to-benefit ratio was superior for the low-dose insert. This is the first pharmacologic treatment that can be administered by an outpatient injection to provide substantial benefit in patients with DME for at least 2 years.

Intravitreal aflibercept for diabetic macular edema: 100-week results from the VISTA and VIVID studies

PURPOSE To compare efficacy and safety of 2 dosing regimens of intravitreal aflibercept injection (IAI) with macular laser photocoagulation for diabetic macular edema (DME). DESIGN Two similarly designed, randomized, phase 3 trials, VISTA(DME) and VIVID(DME). PARTICIPANTS Patients (eyes; n=872) with type 1 or 2 diabetes mellitus who had DME with central involvement. METHODS Eyes received IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 8 weeks after 5 monthly doses (2q8), or laser control. MAIN OUTCOME MEASURES The primary end point was mean change from baseline in best-corrected visual acuity (BCVA) at week 52. This report presents the 100-week results including mean change from baseline in BCVA, proportion of eyes that gained ≥15 letters, and proportion of eyes with a ≥2-step improvement in the Diabetic Retinopathy Severity Scale (DRSS) score. RESULTS Mean BCVA gain from baseline to week 100 with IAI 2q4, IAI 2q8, and laser control was 11.5, 11.1, and 0.9 letters (P < 0.0001) in VISTA and 11.4, 9.4, and 0.7 letters (P < 0.0001) in VIVID, respectively. The proportion of eyes that gained ≥15 letters from baseline at week 100 was 38.3%, 33.1%, and 13.0% (P < 0.0001) in VISTA and 38.2%, 31.1%, and 12.1% (P ≤ 0.0001) in VIVID. The proportion of eyes that lost ≥15 letters at week 100 was 3.2%, 0.7%, and 9.7% (P ≤ 0.0220) in VISTA and 2.2%, 1.5%, and 12.9% (P ≤ 0.0008) in VIVID. Significantly more eyes in the IAI 2q4 and 2q8 groups versus those in the laser control group had a ≥2 step improvement in the DRSS score in both VISTA (37.0% and 37.1% vs. 15.6%; P < 0.0001) and VIVID (29.3% and 32.6% vs. 8.2%; P ≤ 0.0004). In an integrated safety analysis, the most frequent serious ocular adverse event was cataract (2.4%, 1.0%, and 0.3% for 2q4, 2q8, and control). CONCLUSIONS In both VISTA and VIVID, the 52-week visual and anatomic superiority of IAI over laser control was sustained through week 100, with similar efficacy in the 2q4 and 2q8 groups. Safety in these studies was consistent with the known safety profile of IAI.

Fundus Autofluorescence and Progression of Age-related Macular Degeneration

Fundus autofluorescence imaging is an imaging method that provides additional information compared to conventional imaging techniques. It permits to topographically map lipofuscin distribution of the retinal pigment epithelial cell monolayer. Excessive accumulation of lipofuscin granules in the lysosomal compartment of retinal pigment epithelium cells represents a common downstream pathogenetic pathway in various hereditary and complex retinal diseases including age-related macular degeneration (AMD). This comprehensive review contains an introduction in fundus autofluorescence imaging, including basic considerations, the origin of the signal, different imaging methods, and a brief overview of fundus autofluorescence findings in normal subjects. Furthermore, it summarizes cross-sectional and longitudinal fundus autofluorescence findings in patients with AMD, addresses the pathophysiological significance of increased fundus autofluorescence, and characterizes different fundus autofluorescence phenotypes as well as fundus autofluorescence alterations with disease progression.