Srilaxmi Bearelly

Spectral Domain Optical Coherence Tomography Imaging of Geographic Atrophy Margins

OBJECTIVE To test in vivo whether spectral domain optical coherence tomography (SD-OCT) provides adequate resolution for reproducible measurement of photoreceptor (PR) layer at the margins of geographic atrophy (GA), and if it delineates the relationship between PR layer and retinal pigment epithelium at the margins of GA. DESIGN Prospective consecutive case series. PARTICIPANTS Patients with GA secondary to nonneovascular age-related macular degeneration (AMD) identified during routine follow-up at Duke Eye Center between January 3, 2006, and June 3, 2007, and who consented to participate in this study. METHODS We used SD-OCT to image eyes. Multiple B-scans from each eye were saved and independently graded by 2 graders and the following locations were marked: (1) site where PR thickness began to decline below its baseline, (2) site where PR layer disappeared, and (3) site of the GA margin. These data were processed to calculate the locations of PR losses relative to GA margins and were categorized as (A) bridging across GA margins, (B) entirely within GA margins, or (C) entirely outside GA margins. MAIN OUTCOME MEASURES Location of PR loss (bridging across GA margins, entirely within GA margins, or entirely outside GA margins) was calculated. Distances from the GA margin were measured for beginning and ending of PR loss. Interobserver agreement was determined for categories of PR loss as well as locations of PR loss relative to the GA margin. RESULTS We analyzed 500 unique scans. The PR loss occurred most frequently bridging across the GA margin (65% scans), second most frequently entirely inside the GA margin (29% scans), and least frequently entirely outside the GA margin (6% scans). Loss of PR started an average of 61 microm (standard deviation [SD] +/- 235) outside the GA margin, ended an average of 311+/-273 microm inside the GA margin, and spanned an average of 372+/-179 microm. CONCLUSIONS Relative to GA margins in non-neovascular AMD with GA, SD-OCT provides adequate resolution for quantifying PR loss. It may also serve as a means of tracking disease progression in future interventional trials. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Quantitative comparison of drusen segmented on SD-OCT versus drusen delineated on color fundus photographs.

PURPOSE Spectral domain-optical coherence tomography (SD-OCT) may be useful for efficient measurement of drusen in patients with age-related macular degeneration (AMD). Areas identified as drusen from semiautomated segmentation of drusen on SD-OCT were compared to those identified from review of digital color fundus photographs (CFPs). METHODS Twelve eyes with nonneovascular AMD were prospectively imaged with digital CFP and SD-OCT. For each eye, areas on CFP in which at least two of three retina specialists agreed on drusen presence produced the composite CFP drusen map. Automated image analysis produced another CFP map. Areas identified as drusen by segmentation on SD-OCT B-scans were plotted as the SD-OCT drusen map. The CFP and SD-OCT maps were compared and agreement was quantified. Disagreement was characterized into distinct types, and the frequency of each type was quantified. RESULTS There was general agreement between CFP and SD-OCT in identifying presence and absence of drusen, with mean agreement in 82% ± 9% of total image pixels. Most disagreement (80% ± 15%) occurred at drusen margins. There was a trend toward greater detection of drusen with SD-OCT in eyes with larger drusen and with hyperpigmentation. There was a trend toward greater detection of smaller drusen by CFP. CONCLUSIONS Good agreement was demonstrated in drusen detection between CFP and SD-OCT. Areas of disagreement underscore limitations of CFP-based measurement of drusen, particularly in the sizing of large, soft drusen. SD-OCT shows great promise as an adjunctive tool for assessing drusen burden in AMD. (ClinicalTrials.gov number, NCT00734487.).

Association Between Geographic Atrophy Progression and Reticular Pseudodrusen in Eyes With Dry Age-Related Macular Degeneration

PURPOSE To evaluate geographic atrophy (GA) progression in eyes with dry AMD and to determine factors related to GA expansion, notably reticular pseudodrusen (RPD), also known as subretinal drusenoid deposits (SDD) or reticular macular disease (RMD). METHODS This was a retrospective cohort study of patients with dry AMD who were diagnosed with GA in at least one eye and were imaged with sequential fundus autofluorescence (FAF) and/or near infrared reflectance (NIR-R) imaging. Images were analyzed for the presence of GA within the macular region. Geographic atrophy progression was measured in the fields of a modified Wisconsin grid and spatially correlated with RPD. Factors also evaluated for association with GA progression included initial GA size and pattern. RESULTS The study sample included 126 eyes of 92 patients, with an average follow up of 20.4 months (SD = 11.7). At baseline, 93.6% of eyes had RPD, and the average GA area was 2.8 mm(2) (SD = 2.9). The average GA progression rate was 0.8 mm(2)/y (SD = 0.6), with a statistically significant difference between the unilobular and multilobular phenotype groups (0.3 mm(2)/y vs. 0.9 mm(2)/y, P = 0.02). Patients in the lower 50th percentile of initial GA area had a lower progression rate than patients in the upper 50th percentile (0.6 mm(2)/y vs. 1.1 mm(2)/y, P < 0.001). Geographic atrophy progression was more frequent in fields with RPD than in those without RPD (74.2% vs. 41.7%, P < 0.001). CONCLUSIONS The high correlation between the presence of RPD (also known as SDD or RMD) and the presence of GA, and the expansion of GA into areas with these lesions suggest that they are an early manifestation of the process leading to GA.

Ruboxistaurin, a Protein Kinase C β Inhibitor, as an Emerging Treatment for Diabetes Microvascular Complications

OBJECTIVE: To review current clinical data regarding the pharmacologic actions of ruboxistaurin (LY333531) mesylate, an inhibitor of protein kinase C (PKC) β, and its role to potentially reduce the development and/or the progression of diabetic microvascular complications. DATA SOURCES: Primary literature was obtained via a MEDLINE search (1966–August 2004) and through review of pertinent abstracts and presentations at major medical meetings. STUDY SELECTION AND DATA EXTRACTION: Literature relevant to PKC physiology, the pharmacokinetics of ruboxistaurin, and data evaluating the use of ruboxistaurin in treating diabetic microvascular complications in human and relevant animal models was reviewed. DATA SYNTHESIS: PKC is part of a group of intracellular signaling molecules activated in response to various specific hormonal, neuronal, and growth factor stimuli. Hyperglycemia leads to PKC β 1 and 2 isoform activation, which experimentally has been shown to contribute to the development and progression of diabetic microvascular complications (retinopathy, nephropathy, neuropathy) through various biochemical mechanisms. Animal and/or human studies using ruboxistaurin mesylate, a novel, highly selective inhibitor of PKC β, have shown delay in the progression and, in some cases, reversal of diabetic retinopathy, nephropathy, and neuropathy. CONCLUSIONS: Ruboxistaurin mesylate, by inhibiting excessive activation of certain PKC isoforms, has the potential to reduce the burden of microvascular complications for patients with diabetes.

Reticular macular disease is associated with multilobular geographic atrophy in age-related macular degeneration.

Purpose: To investigate the incidence of reticular macular disease (RMD), a subphenotype of age-related macular degeneration, in multilobular geographic atrophy (GA) and its relation to GA progression. Methods: One hundred and fifty-seven eyes of 99 subjects with age-related macular degeneration, primary GA, and good quality autofluorescence, and/or infrared images were classified into unilobular GA (1 lesion) or multilobular GA (≥2 distinct and/or coalescent lesions). Thirty-four subjects (50 eyes) had serial imaging. The authors determined the spatiotemporal relationships of RMD to GA and GA progression rates in five macular fields. Results: 91.7% eyes (144 of 157) had multilobular GA, 95.8% of which exhibited RMD. In subjects with serial imaging, the mean GA growth rate significantly differed between the unilobular and multilobular groups (0.40 vs. 1.30 mm2/year, P < 0.001). Of the macular fields in these eyes, 77.1% of fields with RMD at baseline showed subsequent GA progression, while 53.4% of fields without RMD showed progression (P < 0.001). Percentage of fields with RMD significantly correlated with GA progression rate (P = 0.01). Conclusion: Autofluorescence and infrared imaging demonstrates that RMD is nearly always present with multilobular GA in age-related macular degeneration. Furthermore, GA lobules frequently develop in areas of RMD, suggesting progression of a single underlying disease process.

Reticular pseudodrusen in early age-related macular degeneration are associated with choroidal thinning.

PURPOSE To compare choroidal thickness (CT) measurements in early AMD between patients with and without reticular pseudodrusen (RPD) using spectral-domain optical coherence tomography (SD-OCT). METHODS This cross-sectional study examined 84 age- and sex-matched AMD patients (40 RPD [63 eyes], 44 non-RPD [75 eyes]). Fundus photographs and scanning laser ophthalmoscopy images were graded to identify RPD and non-RPD groups by three retinal specialists (MO, SY, SB) who were masked to corresponding SD-OCTs. CT at the fovea and 2400 to 3000 μm superior and inferior to the fovea was measured on SD-OCT by a grader (AG) and reviewed by a retinal specialist (SB). Only images with a clear posterior choroidal margin were analyzed (six eyes excluded due to poor image quality), and enhanced depth imaging SD-OCT was used when available (20 of 138 eyes). Greatest retinal thickness (RT) on horizontal foveal SD-OCT was also recorded. RESULTS Mean CTs in the superior, foveal, and inferior macula in RPD (191.3 μm ± 57.9 SD, 176.3 μm ± 60.5 SD, 179.7 μm ± 56.24 SD) were significantly less than that of non-RPD (228.0 μm ± 66.1 SD, 216.5 μm ± 70.3 SD, 224.4 μm ± 71.9 SD; P = 0.0010, P = 0.0005, P = 0.0001, respectively), as was greatest RT (P = 0.0301). CONCLUSIONS CT was thinner throughout the macula in the RPD group as compared with the non-RPD group. The current analysis supports an association between RPD and a thinned choroidal layer and is consistent with a choroidal etiology of RPD. CT may be integral to understanding RPD, and may be helpful in stratifying AMD progression risk.

Comparison of color fundus photographs and fundus autofluorescence images in measuring geographic atrophy area.

Purpose: To assess the agreement between color fundus photographs (CFP) and fundus autofluorescence (FAF) images when measuring geographic atrophy (GA) area and reproducibility of measurements between graders. Frequency and disagreement types were also determined. Methods: Eyes with GA secondary to age-related macular degeneration had CFP and FAF imaging on the same day. Seventy-two eyes from 72 patients were included in the analysis. Three graders calculated GA area using digital imaging software. Main outcome measures included agreement between graders for GA area on both FAF and CFP and agreement between both imaging modalities. Results: The intraclass correlation for the 3 graders for FAF images was 0.99 (95% confidence interval, 0.98–0.99). For CFP, it was 0.96 (95% confidence interval, 0.94–0.97). The intraclass correlation between imaging modalities for Graders 1, 2, and 3 were 0.93, 0.85, and 0.87, respectively. Sensitivities to detect involvement of fovea (CFP, 86–97%; FAF, 72–93%) and specificities to detect sparing of fovea (CFP, 74–76%; FAF, 59–88%) overlapped between imaging modalities. Conclusion: Both CFP and FAF imaging are reliable for measuring GA area. Interobserver agreement was slightly higher for FAF images. Although the high agreement between modalities suggests that either would be appropriate for measuring GA area, using both may be the best approach for following GA progression.

Use of Fundus Autofluorescence Images to Predict Geographic Atrophy Progression

Purpose: Fundus autofluorescence imaging has been shown to be helpful in predicting progression of geographic atrophy (GA) secondary to age-related macular degeneration. We assess the ability of fundus autofluorescence imaging to predict rate of GA progression using a simple categorical scheme. Methods: Subjects with GA secondary to age-related macular degeneration with fundus autofluorescence imaging acquired at least 12 months apart were included. Rim area focal hyperautofluorescence was defined as percentage of the 500-μm-wide margin bordering the GA that contained increased autofluorescence. Rim area focal hyperautofluorescence on baseline fundus autofluorescence images was assessed and categorized depending on the extent of rim area focal hyperautofluorescence (Category 1: ≤33%; Category 2: between 33 and 67%; Category 3: ≥67%). Total GA areas at baseline and follow-up were measured to calculate change in GA progression. Results: Forty-five eyes of 45 subjects were included; average duration of follow-up was 18.5 months. Median growth rates differed among categories of baseline rim area focal hyperautofluorescence (P = 0.01 among Categories 1, 2, and 3; P = 0.008 for Category 1 compared with Category 3, Jonckheere-Terpstra test). Conclusion: A simple categorical scheme that stratifies the amount of increased autofluorescence in the 500-μm margin bordering GA may be used to differentiate faster and slower progressors.

Anaphylaxis following intravenous fluorescein angiography in a vitreoretinal clinic: report of 4 cases

OBJECTIVE To assess the incidence of anaphylaxis following intravenous fluorescein angiography (IVFA) at 1 satellite clinic. STUDY DESIGN Observational case series. PARTICIPANTS Records from 1400 patients were reviewed. METHODS Consecutive vitreoretinal patients who underwent IVFA between 1998 and 2005 at 1 satellite office were included for retrospective analysis. RESULTS Anaphylaxis developed in 4 of 1400 (0.3%) patients within minutes after they had received intravenous fluorescein. In each case, the reaction was recognized promptly and treated with injectable epinephrine by the physician, and symptoms resolved quickly. The ambulance was called in all 4 cases. In the literature, reports of 21 cases of anaphylaxis and 7 deaths have been published in the past 55 years. CONCLUSIONS Although uncommon, anaphylaxis as a reaction to intravenous fluorescein does occur. As this is potentially life-threatening, prompt diagnosis and treatment are crucial. An emergency care plan should be available.

The external limiting membrane in early-onset Stargardt disease.

PURPOSE To describe pathologic changes of the external limiting membrane (ELM) in young patients with early-onset Stargardt (STGD1) disease. METHODS Twenty-six STGD1 patients aged younger than 20 years with confirmed disease-causing adenosine triphosphate-binding cassette, subfamily A, member 4 (ABCA4) alleles and 30 age-matched unaffected individuals were studied. Spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (AF), and color fundus photography (CFP) images, as well as full-field electroretinograms were obtained and analyzed for one to four visits in each patient. RESULTS The ELM in all patients exhibited a distinct thickening that was not observed in unaffected individuals. In addition, accumulations of reflective deposits were noted in the outer nuclear layer in every patient. Four patients exhibited a concave protuberance or bulging of a thickened and hyperreflective ELM band within the fovea containing preserved photoreceptors. Longitudinal SD-OCT data in several patients revealed the persistence of this ELM abnormality over a period of time (1-4 years). Furthermore, the edges of the inner segment ellipsoid band appeared to recede earlier than the ELM band in active lesions. CONCLUSIONS Structural changes seen in the ELM of this cohort may reflect a gliotic response to cellular stress at the photoreceptor level in early-onset STGD1.