Christian K. Brinkmann

Combined Confocal Scanning Laser Ophthalmoscopy and Spectral-Domain Optical Coherence Tomography Imaging of Reticular Drusen Associated with Age-Related Macular Degeneration

PURPOSE To determine microstructural retinal alterations associated with reticular drusen in patients with age-related macular degeneration (AMD) using high-resolution in vivo imaging techniques. DESIGN Retrospective case series. PARTICIPANTS A total of 116 eyes of 78 AMD patients with reticular drusen were examined. METHODS Simultaneous spectral-domain optical coherence tomography (SD OCT; 870 nm, 40,000 A-scans/sec) and near-infrared confocal scanning laser ophthalmoscopy (cSLO; 830 nm) were performed using a combined imaging instrument (Spectralis HRA+OCT, Heidelberg Engineering, Heidelberg, Germany). Individual anatomic layers in SD OCT were evaluated and correlated to en face cSLO fundus imaging. MAIN OUTCOME MEASURES Description of corresponding structural changes in areas of reticular drusen. RESULTS Reticular drusen appeared as an interlacing network of round or oval irregularities by near-infrared cSLO reflectance imaging. On SD OCT, reticular drusen corresponded to marked changes at a level anterior to the retinal pigment epithelium (RPE) and Bruchs membrane complex to the interface of inner and outer photoreceptor segment layer (IPRL). Individual reticular drusen correlated to focal elevations of the IPRL, accumulation of highly reflective material below the IPRL, and an increased distance between the IPRL and RPE. CONCLUSIONS The findings indicate that the morphologic substrate of reticular drusen is the accumulation of highly reflective material within outer retinal layers anterior to the RPE. This is in contrast to previous assumptions pointing toward a localization of abnormal material at the level of the inner choroid. Although the origin of the material is unknown, the results may indicate a role for primary abnormalities in the neurosensory retina. Because reticular drusen represent high-risk markers for the progression of AMD, their ready identification is relevant both for natural history studies as well as for interventional trials.

Semiautomated Image Processing Method for Identification and Quantification of Geographic Atrophy in Age-Related Macular Degeneration

PURPOSE To determine intraobserver and interobserver longitudinal measurement variability of novel semiautomated software for quantification of age-related macular degeneration-associated geographic atrophy (GA) based on confocal scanning laser ophthalmoscopy fundus autofluorescence (FAF) imaging. METHODS Three-field FAF (excitation 488 nm, emission 500-700 nm), near-infrared reflectance (820 nm), and blue reflectance (488 nm) images of 30 GA subjects were recorded according to a standardized protocol at baseline after 6 and 12 months. At all visits, the GA area was analyzed on central FAF images by seven independent readers using semiautomated software. The software allows direct export of FAF images from the database and semiautomated detection of atrophic areas by shadow correction, vessel detection, and selection of seed points. RESULTS The mean size of atrophy at baseline and the mean progression rate were 5.96 mm² (range, 1.80-15.87) and 1.25 mm²/year (0.42-2.93), respectively. Mean difference of interobserver agreement (Bland-Altman statistics) ranged from -0.25 to 0.30 mm² for the baseline visit and from -0.14 to 0.11 mm²/year for the atrophy progression rate. Corresponding reflectance images were helpful for lesion boundary discrimination, particularly for evaluation of foveal GA involvement and when image quality was poor. CONCLUSIONS The new image processing software offers an accurate, reproducible, and time-efficient identification and quantification of outer retinal atrophy and its progression over time. It facilitates measurements both in natural history studies and in interventional trials to evaluate new pharmacologic agents designed to limit GA enlargement.

Tracking Progression with Spectral-Domain Optical Coherence Tomography in Geographic Atrophy Caused by Age-Related Macular Degeneration

PURPOSE To investigate, with the use of spectral-domain optical coherence tomography (SD-OCT), microstructural alterations over time in eyes with progressive geographic atrophy (GA) due to age-related macular degeneration. METHODS Forty-six eyes of 26 patients (median age, 77.9 years [interquartile range (IQR), 71.8-81.0]) with GA without evidence of active or previous neovascular disease at baseline were examined by simultaneous confocal scanning laser ophthalmoscopy (cSLO) and SD-OCT. Serial examinations with alignment of follow-up to baseline scans were performed over a median period of 12.2 months (IQR, 10.2-15.3). Longitudinal SD-OCT variations were evaluated, including quantification of retinal thickness (RT) change and lateral spread of GA (LSGA) at a temporal, nasal, inferior, and superior GA border-section in each eye. RESULTS GA-enlargement was characterized by progressive loss of the outer hyperreflective SD-OCT bands and by thinning of the outer nuclear layer with subsequent approach of the outer plexiform layer toward Bruchs membrane. In the perilesional zone, various dynamic changes were recorded, including migration of hyperreflective material and changes in drusen height. At the borders, there was a median RT change of -14.09 microm/y (IQR -26.21 to -7.48 microm/y). The median LSGA was 106.90 microm/y (IQR, 55.44-161.70 microm/y). Both parameters showed only moderate intraocular agreement (RT change: intraclass correlation coefficient [ICC], 0.54; 95% CI, 0.39-0.67; LSGA: ICC, 0.49; 95% CI, 0.34-0.64) and no statistical significant difference for one location (RT change, P = 0.125; LSGA, P = 0.516; likelihood ratio test). CONCLUSIONS Combined cSLO and SD-OCT imaging provides unprecedented insight into dynamic microstructural changes of GA enlargement that may help to better understand the pathogenesis of the disease. Quantitative progression data indicate local factors may exist that drive progression in junctional areas (ClinicalTrials.gov number, NCT00393692).

Fundus Autofluorescence and Spectral-Domain Optical Coherence Tomography Characteristics in a Rapidly Progressing Form of Geographic Atrophy

PURPOSE To further characterize a previously described phenotypic variant of geographic atrophy (GA) associated with rapid progression and a diffuse-trickling appearance on fundus autofluorescence (FAF). METHODS Thirty-six patients (60 eyes; 72.2% women; mean age, 69.4 ± 10.7 years) with this distinct phenotype were examined by simultaneous confocal scanning laser ophthalmoscopy (cSLO) and spectral-domain optical coherence tomography (SD-OCT) imaging. Images were qualitatively and quantitatively analyzed and compared with 60 eyes (38 patients) with non diffuse-trickling GA. RESULTS The atrophic area in the diffuse-trickling phenotype showed a grayish FAF signal and characteristic coalescent lobular configuration at the lesion boundaries. SD-OCT revealed a marked splitting of band 4 (the presumptive retinal pigment epithelium (RPE)/Bruchs membrane (BM) complex) in all 240 analyzed border sections of diffuse-trickling GA eyes (four borders/eye) with a mean distance between the inner and outer parts of band 4 of 23.2 ± 7.5 μm. This finding was present in only 13.8% (33/240) of analyzed border sections in non diffuse-trickling GA. CONCLUSIONS Patients with the rapidly progressing diffuse-trickling GA phenotype exhibited a characteristic marked separation within the RPE/BM complex on SD-OCT-imaging. The presumed histopathologic correlates are basal laminar deposits. Such deposits may promote RPE cell death and, thus, contribute to rapid GA progression. The persistence of these deposits within the atrophic lesion may account for the distinct grayish FAF appearance, which differs from the markedly reduced signal in other forms of GA. Identification of such alterations based on FAF and SD-OCT imaging may be helpful in future interventional trials directed toward slowing GA progression. (ClinicalTrials.gov number, NCT00393692.).

Imaging Geographic Atrophy in Age-Related Macular Degeneration

Advances in retinal imaging technology have largely contributed to the understanding of the natural history, prognostic markers and disease mechanisms of geographic atrophy (GA) due to age-related macular degeneration. There is still no therapy available to halt or slow the disease process. In order to evaluate potential therapeutic effects in interventional trials, there is a need for precise quantification of the GA progression rate. Fundus autofluorescence imaging allows for accurate identification and segmentation of atrophic areas and currently represents the gold standard for evaluating progressive GA enlargement. By means of high-resolution spectral-domain optical coherence tomography, distinct microstructural alterations related to GA can be visualized.

Treatment of choroidal neovascularization due to angioid streaks: a comprehensive review.

Purpose: To evaluate different therapies for choroidal neovascularization (CNV) due to angioid streaks (AS). Methods: Studies were identified by a systematic literature search and were included in the analysis based on predefined criteria. Primary outcome measure was change in best-corrected visual acuity (BCVA). Results: Fifty-four relevant studies were identified and included mostly uncontrolled case series. No randomized controlled trials were available. Treatment with vascular endothelial growth factor inhibitors improved or stabilized BCVA in all case series. Photodynamic therapy slowed down disease progression with stabilization or decrease of BCVA. Individual BCVA and follow-up data for each treated eye were reported in >160 cases for both treatments, vascular endothelial growth factor inhibitors and photodynamic therapy. In a pooled analysis of those studies, the difference of mean change in BCVA between both treatment groups was estimated as approximately 6 lines (0.59 logMAR [95% confidence interval, 0.38-0.8; P < 0.0001]). A better baseline BCVA was associated with a better BCVA outcome (P < 0.0001). Laser photocoagulation yielded comparable results as photodynamic therapy but application was mostly restricted to extrafoveal lesions, was complicated by frequent recurrences, and led to more retinal damage with subsequent absolute scotomas. Combination therapies seem to be not superior to monotherapy. Conclusion: Intravitreal vascular endothelial growth factor inhibitors are currently the most effective treatment of CNV due to angioid streaks.

Release And Velocity Of Micronized Dexamethasone Implants With An Intravitreal Drug Delivery System: Kinematic Analysis With a High-speed Camera

Purpose: Ozurdex, a novel dexamethasone (DEX) implant, is released by a drug delivery system into the vitreous cavity. We analyzed the mechanical release aperture of the novel applicator, obtained real-time recordings using a high-speed camera system and performed kinematic analysis of the DEX application. Design: Experimental study. Methods: The application of intravitreal DEX implants (6 mm length, 0.46 mm diameter; 700 &mgr;g DEX mass, 0.0012 g total implant mass) was recorded by a high-speed camera (500 frames per second) in water (Group A: n = 7) or vitreous (Group B: n = 7) filled tanks. Kinematic analysis calculated the initial muzzle velocity as well as the impact on the retinal surface at approximately 15 mm of the injected drug delivery system implant in both groups. A series of drug delivery system implant positions was obtained and graphically plotted over time. Results: High-speed real-time recordings revealed that the entire movement of the DEX implant lasted between 28 milliseconds and 55 milliseconds in Group A and 1 millisecond and 7 milliseconds in Group B. The implants moved with a mean muzzle velocity of 820 ± 350 mm/s (±SD, range, 326–1,349 mm/s) in Group A and 817 ± 307 mm/s (±SD, range, 373–1,185 mm/s) in Group B. In both groups, the implant gradually decelerated because of drag force. With greater distances, the velocity of the DEX implant decreased exponentially to a complete stop at 13.9 mm to 24.7 mm in Group A and at 6.4 mm to 8.0 mm in Group B. Five DEX implants in Group A reached a total distance of more than 15 mm, and their calculated mean velocity at a retinal impact of 15 mm was 408 ± 145 mm/s (±SD, range, 322–667 mm/s), and the consecutive normalized energy was 0.55 ± 0.44 J/m2 (±SD). In Group B, none of the DEX implants reached a total distance of 6 mm or more. An accidental application at an angle of 30 grade and consecutively reduced distance of approximately 6 mm may result in a mean velocity of 844 and mean normalized energy of 0.15 J/m2 (SD ± 0.47) in a water-filled eye. Conclusion: The muzzle velocity of DEX implants is approximately 0.8 m/s and decreases exponentially over distance. The drag over time in vitreous is faster than in water. The calculated retinal impact energy does not reach reported damage levels for direct foreign bodies or other projectiles.

Directional Kinetics of Geographic Atrophy Progression in Age-Related Macular Degeneration with Foveal Sparing

PURPOSE To describe the directional kinetics of the spread of geographic atrophy (GA) spread in eyes with age-related macular degeneration and foveal sparing. DESIGN Prospective, noninterventional natural history study: Fundus Autofluorescence Imaging in Age-Related Macular Degeneration (FAM; clinicaltrials.gov identifier, NCT00393692). SUBJECTS Participants of the FAM study exhibiting foveal sparing of GA. METHODS Eyes were examined longitudinally with fundus autofluorescence (FAF; excitation wavelength, 488 nm; emission wavelength, >500 nm) and near infrared (NIR) reflectance imaging (Spectralis HRA+OCT or HRA2; Heidelberg Engineering, Heidelberg, Germany). Areas of foveal sparing and GA were measured by 2 independent readers using a semiautomated software tool that allows for combined NIR reflectance and FAF image grading (RegionFinder; Heidelberg Engineering). A linear mixed effect model was used to model GA kinetics over time. MAIN OUTCOME MEASURE Change of GA lesion size over time (central vs. peripheral progression). RESULTS A total of 47 eyes of 36 patients (mean age, 73.8±7.5 years) met the inclusion criteria. Mean follow-up time was 25.2±16.9 months (range, 5.9-74.6 months). Interreader agreement for measurements of GA and foveal-sparing size were 0.995 and 0.946, respectively. Mean area progression of GA toward the periphery was 2.27±0.22 mm(2)/year and 0.25±0.03 mm(2)/year toward the center. Analysis of square root-transformed data revealed a 2.8-fold faster atrophy progression toward the periphery than toward the fovea. Faster atrophy progression toward the fovea correlated with faster progression toward the periphery in presence of marked interindividual differences. CONCLUSIONS The results demonstrate a significantly faster centrifugal than centripetal GA spread in eyes with GA and foveal sparing. Although the underlying pathomechanisms for differential GA progression remain unknown, local factors may be operative that protect the foveal retina-retinal pigment epithelial complex. Quantification of directional spread characteristics and modeling may be useful in the design of interventional clinical trials aiming to prolong foveal survival in eyes with GA.

Klinische Merkmale, Progression und Risikofaktoren bei geographischer Atrophie

Geographic atrophy (GA) as the late stage manifestation of age-related macular degeneration (AMD) is a progressive disease process afflicting the retinal pigment epithelium, choriocapillaris and the outer neurosensory retina. GA represents a complex, multifactorial disease governed by the interdependence of genetic, endogenous and exogenous factors. Diagnosis and monitoring of GA progression is largely based on various retinal imaging modalities. After the breakthrough in the treatment of wet AMD GA represents a large clinical challenge. Recent studies have contributed to a better understanding of the pathophysiological pathways, natural history and predictive markers for progression.

Visual field indices and patterns of visual field deficits in mesopic and dark-adapted two-colour fundus-controlled perimetry in macular diseases

Background/Aims To analyse the retest reliability of visual field indices and to describe patterns of visual field deficits in mesopic and dark-adapted two-colour fundus-controlled perimetry (FCP) in macular diseases. Methods Seventy-seven eyes (30 eyes with macular diseases and 47 normal eyes) underwent duplicate mesopic and dark-adapted two-colour FCP (Scotopic Macular Integrity Assessment, CenterVue). Non-weighted (mean defect, loss variance), variability-weighted (mean deviation, pattern standard deviation (PSD)) and graphical (cumulative defect (Bebie) curves) indices were computed. Reproducibility (coefficient of repeatability, CoR) of these indices was assessed. Cluster analysis was carried out to identify patterns of visual field deficits. Results The intrasession reproducibility was lower for the mean defect as compared with the mean deviation (CoR (dB) 2.67 vs 2.57 for mesopic, 1.71 vs 1.45 for dark-adapted cyan, 1.94 vs 1.87 for dark-adapted red testing) and lower for the square-root loss variance as compared with the PSD (CoR (dB) 1.48 vs 1.34, 0.77 vs 0.65, 1.23 vs 1.03). Hierarchical cluster analysis of the indices disclosed six patterns of visual field deficits (approximately unbiased P value>0.95) with varying degrees of global versus focal defect and rod versus cone dysfunction. These were also reflected by the cumulative defect curves. Conclusion FCP with mesopic and dark-adapted two-colour testing allows for reproducible assessment of different types of retinal sensitivity, whereby mean deviation and PSD exhibited the better retest reliability of the tested indices. Distinct patterns of retinal dysfunction can be identified using this setup, reflecting variable degrees of rod and cone dysfunction in different macular diseases. Dark-adapted two-colour FCP provides additional diagnostic information and allows for refined structure–function correlation in macular diseases.