Publications

2015

Grassi C, Crnej A, Paschalis E, Colby K, Dohlman C, Chodosh J. Idiopathic vitritis in the setting of Boston keratoprosthesis.. Cornea. 2015;34(2):165–70.

PURPOSE: The aim of this study was to revisit the clinical paradigm attributed to Boston keratoprosthesis recipients presenting with idiopathic vitreous inflammation. METHODS: A retrospective chart review was performed of keratoprosthesis recipients at Massachusetts Eye and Ear Infirmary, from January 2000 to August 2013, for demographic data, indication(s) for surgery, timing and presentation of vitreous inflammation, and best-corrected visual acuity at baseline, on presentation, and after resolution of vitritis. RESULTS: Twenty-three (23 eyes) of 346 patients developed idiopathic vitreous inflammation after keratoprosthesis implantation. Six of 23 patients presented with signs and symptoms similar to infectious endophthalmitis but were culture negative. The proportion of patients who fit the previous paradigm of sudden painless loss of vision without external signs of infection ("sterile vitritis") at their first presentation with vitritis was only 4 of 23. Vision decline was variable (median, 9 lines on Snellen chart; range, 0-24), as was time to recovery of best vision (median, 8.9 weeks; range, 0.9-36.7). Nine eyes had repeat bouts (43 episodes in 23 patients). Ten of 43 episodes did not recover to baseline vision. Seventeen of 23 eyes with idiopathic vitritis after keratoprosthesis later developed other complications. CONCLUSIONS: The current paradigm for idiopathic vitritis after keratoprosthesis implantation includes sudden painless loss of vision with full recovery of vision on treatment with periocular corticosteroids. However, idiopathic vitritis after keratoprosthesis can also mimic infectious endophthalmitis with pain and external signs of inflammation. Visual loss can be gradual. Vision may not recover to baseline despite treatment. Vitritis may be a part of a common pathway of chronic inflammation after keratoprosthesis.

Navarro-Gomez D, Leipzig J, Shen L, Lott M, Stassen A, Wallace D, Wiggs J, Falk M, Oven M, Gai X. Phy-Mer: a novel alignment-free and reference-independent mitochondrial haplogroup classifier.. Bioinformatics. 2015;31(8):1310–2.

MOTIVATION: All current mitochondrial haplogroup classification tools require variants to be detected from an alignment with the reference sequence and to be properly named according to the canonical nomenclature standards for describing mitochondrial variants, before they can be compared with the haplogroup determining polymorphisms. With the emergence of high-throughput sequencing technologies and hence greater availability of mitochondrial genome sequences, there is a strong need for an automated haplogroup classification tool that is alignment-free and agnostic to reference sequence. RESULTS: We have developed a novel mitochondrial genome haplogroup-defining algorithm using a k-mer approach namely Phy-Mer. Phy-Mer performs equally well as the leading haplogroup classifier, HaploGrep, while avoiding the errors that may occur when preparing variants to required formats and notations. We have further expanded Phy-Mer functionality such that next-generation sequencing data can be used directly as input. AVAILABILITY AND IMPLEMENTATION: Phy-Mer is publicly available under the GNU Affero General Public License v3.0 on GitHub (https://github.com/danielnavarrogomez/phy-mer). CONTACT: Xiaowu_Gai@meei.harvard.edu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Simavli H, Que CJ, Akduman M, Rizzo J, Tsikata E, Boer J, Chen T. Diagnostic capability of peripapillary retinal thickness in glaucoma using 3D volume scans.. Am J Ophthalmol. 2015;159(3):545–56.e2.

PURPOSE: To determine the diagnostic capability of spectral-domain optical coherence tomography (SD OCT) peripapillary retinal thickness (RT) measurements from 3-dimensional (3D) volume scans for primary open-angle glaucoma (POAG). DESIGN: Cross-sectional study. METHODS: setting: Institutional. study population: 156 patients (89 POAG and 67 normal subjects). observation procedures: One eye of each subject was included. SD OCT peripapillary RT values from 3D volume scans were calculated for 4 quadrants of 3 different sized annuli. Peripapillary retinal nerve fiber layer (RNFL) thickness values were also determined. main outcome measures: Area under the receiver operating characteristic curve (AUROC) values, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. RESULTS: The top 5 RT AUROCs for all glaucoma patients and for a subset of early glaucoma patients were for the inferior quadrant of outer circumpapillary annulus of circular grid (OCA) 1 (0.959, 0.939), inferior quadrant of OCA2 (0.945, 0.921), superior quadrant of OCA1 (0.890, 0.811), inferior quadrant of OCA3 (0.887, 0.854), and superior quadrant of OCA2 (0.879, 0.807). Smaller RT annuli OCA1 and OCA2 consistently showed better diagnostic performance than the larger RT annulus OCA3. For both RNFL and RT measurements, best AUROC values were found for inferior RT OCA1 and OCA2, followed by inferior and overall RNFL thickness. CONCLUSION: Peripapillary RT measurements from 3D volume scans showed excellent diagnostic performance for detecting both glaucoma and early glaucoma patients. Peripapillary RT values have the same or better diagnostic capability compared to peripapillary RNFL thickness measurements, while also having fewer algorithm errors.

Liu Y, Simavli H, Que CJ, Rizzo J, Tsikata E, Maurer R, Chen T. Patient characteristics associated with artifacts in Spectralis optical coherence tomography imaging of the retinal nerve fiber layer in glaucoma.. Am J Ophthalmol. 2015;159(3):565–76.e2.

PURPOSE: To determine patient factors and eye conditions associated with artifacts in Spectralis optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) scans. DESIGN: Retrospective cross-sectional study. METHODS: The prevalence of 12 artifact types were described in this review of 2313 eye scans from 1188 patients who underwent a complete eye examination with Spectralis OCT scanning during the period of September 2009 to July 2013. The generalized estimating equations model was used to analyze associations between increased artifact prevalence and 10 patient characteristics, which included age, sex, race, visual acuity, refractive error, astigmatism, cataract status, glaucoma staging, visual field reliability, and glaucoma diagnosis. RESULTS: A total of 1070 or 46.3% of the 2313 eye scans had at least 1 artifact. Decentration error was the most common artifact (27.8%), followed by posterior vitreous detachment artifacts (14.4%). Visual acuity of less than 20/40 (P < .0001), presence of moderate to severe cataracts (P < .0001), advanced stage of glaucoma (P < .0001), and a diagnosis of open-angle glaucoma (P = .0003) were associated with increased prevalence of artifacts. CONCLUSIONS: Clinicians should first assess scans for artifacts before making therapeutic decisions based on RNFL thickness measurements.

Lim L, Ling L, Cheung CMG, Ong PG, Gong L, Tai S, Mathur R, Wong D, Foulds W, Wong TY. Relationship of systemic endothelial function and peripheral arterial stiffness with diabetic retinopathy.. Br J Ophthalmol. 2015;99(6):837–41.

BACKGROUND: To investigate possible associations between diabetic retinopathy (DR) and systemic vascular endothelial function and arterial stiffness measured using reactive hyperaemia peripheral arterial tonometry. METHODS: This was a cross-sectional observational clinical study. Subjects with diabetes were recruited and DR was graded from retinal photographs. Systemic endothelial function was measured using reactive hyperaemia peripheral arterial tonometry (EndoPAT) and expressed as the reactive hyperaemia index (RHI). Peripheral arterial stiffness was measured using the same device and expressed as the augmentation index (AI). RESULTS: In total, 164 eyes of 95 Chinese patients were evaluated. The mean age of the subject eyes was 60.1±8.2 years and 76.8% were men. The mean duration of diabetes was 15.5±9.8 years, and the mean HbA1c was 8.1±1.4%. In age-gender-adjusted models, increasing severity of DR was associated with increasing mean RHI (p=0.001) and increasing mean AI (p<0.001). In multivariate models, adjusting additionally for smoking, mean duration of diabetes, HbA1c and hypertension, the associations with RHI and AI persisted (p=0.011 and 0.001, respectively). In analyses of the dichotomous outcomes clinically significant macular oedema (CSME), moderate DR and vision-threatening DR, AI was a significant predictor of CSME and vision-threatening DR. In multivariate-adjusted models, for every SD increase in AI, the odds of having CSME was 1.78 times higher (95% CI 1.05 to 2.99; p=0.029). For every SD increase in AI, the odds of having vision-threatening DR was 1.73 times higher (95% CI 1.17 to 2.56; p=0.003). CONCLUSIONS: Subjects with more severe DR have larger peripheral reactive hyperaemic responses and greater peripheral vascular stiffness. These findings support the link between the microvascular changes of diabetes and macrovascular disease.

Consugar M, Navarro-Gomez D, Place E, Bujakowska K, Sousa M, Fonseca-Kelly Z, Taub D, Janessian M, Wang DY, Au E, Sims K, Sweetser D, Fulton A, Liu Q, Wiggs J, Gai X, Pierce E. Panel-based genetic diagnostic testing for inherited eye diseases is highly accurate and reproducible, and more sensitive for variant detection, than exome sequencing.. Genet Med. 2015;17(4):253–61.

PURPOSE: Next-generation sequencing-based methods are being adopted broadly for genetic diagnostic testing, but the performance characteristics of these techniques with regard to test accuracy and reproducibility have not been fully defined. METHODS: We developed a targeted enrichment and next-generation sequencing approach for genetic diagnostic testing of patients with inherited eye disorders, including inherited retinal degenerations, optic atrophy, and glaucoma. In preparation for providing this genetic eye disease (GEDi) test on a CLIA-certified basis, we performed experiments to measure the sensitivity, specificity, and reproducibility, as well as the clinical sensitivity, of the test. RESULTS: The GEDi test is highly reproducible and accurate, with sensitivity and specificity of 97.9 and 100%, respectively, for single-nucleotide variant detection. The sensitivity for variant detection was notably better than the 88.3% achieved by whole-exome sequencing using the same metrics, because of better coverage of targeted genes in the GEDi test as compared with a commercially available exome capture set. Prospective testing of 192 patients with inherited retinal degenerations indicated that the clinical sensitivity of the GEDi test is high, with a diagnostic rate of 51%. CONCLUSION: Based on quantified performance metrics, the data suggest that selective targeted enrichment is preferable to whole-exome sequencing for genetic diagnostic testing.Genet Med 17 4, 253-261.

Wan M, VanderVeen D. Eye disorders in newborn infants (excluding retinopathy of prematurity).. Arch Dis Child Fetal Neonatal Ed. 2015;100(3):F264–9.

A screening eye examination is an essential part of the newborn assessment. The detection of many ocular disorders in newborn infants can be achieved through careful observation of the infant's visual behaviour and the use of a direct ophthalmoscope to assess the ocular structures and check the red reflex. Early diagnosis and subspecialty referral can have a critical impact on the prognosis for many ocular conditions, including potentially blinding but treatable conditions such as congenital cataracts, life-threatening malignancies such as retinoblastoma and harbingers of disease elsewhere such as sporadic aniridia and its association with the development of Wilms tumour.

Choi W, Byun YJ, Jung E, Noh H, Hajrasouliha A, Sadrai Z, Chang EJ, Lee J, Lee HK. Chemokine decoy receptor D6 mimicking trap (D6MT) prevents allosensitization and immune rejection in murine corneal allograft model.. J Leukoc Biol. 2015;97(2):413–24.

Although corneal allotransplantation is performed in the immune-privileged cornea, many grafts are still rejected after transplantation. This study examined the role of chemokine receptor D6 expression in a corneal allograft rejection, investigated the modulation of D6 expression in cells, and determined the effect of D6 on graft survival. Interestingly, D6 was highly expressed in CD45 -: cells and the corneal epithelium of accepted corneal allografts. From the mouse corneal allograft model, TGF-β was found to play a key role in D6 up-regulation, leading to reduced CCL2, CCL5, and CCL3. To modulate D6 chemokine binding, a D6MT was developed and showed effective chemokine trapping through SPR and FACS assays. By treating corneal allografts with D6MT, the allograft survival rate was improved, and (lymph) angiogenesis was reduced. Direct allosensitization and DC LN homing was drastically reduced in the mouse corneal allograft model. These findings suggest that TGF-β is a positive regulator of D6 expression, and it is a potential therapeutic target to enhance the survival of corneal allografts.

Bauer C, Yazzolino L, Hirsch G, Cattaneo Z, Vecchi T, Merabet L. Neural correlates associated with superior tactile symmetry perception in the early blind. Cortex. 2015;63:104–117.
Symmetry is an organizational principle that is ubiquitous throughout the visual world. However, this property can also be detected through non-visual modalities such as touch. The role of prior visual experience on detecting tactile patterns containing symmetry remains unclear. We compared the behavioral performance of early blind and sighted (blindfolded) controls on a tactile symmetry detection task. The tactile patterns used were similar in design and complexity as in previous visual perceptual studies. The neural correlates associated with this behavioral task were identified with functional magnetic resonance imaging (fMRI). In line with growing evidence demonstrating enhanced tactile processing abilities in the blind, we found that early blind individuals showed significantly superior performance in detecting tactile symmetric patterns compared to sighted controls. Furthermore, comparing patterns of activation between these two groups identified common areas of activation (e.g. superior parietal cortex) but key differences also emerged. In particular, tactile symmetry detection in the early blind was also associated with activation that included peri-calcarine cortex, lateral occipital (LO), and middle temporal (MT) cortex, as well as inferior temporal and fusiform cortex. These results contribute to the growing evidence supporting superior behavioral abilities in the blind, and the neural correlates associated with crossmodal neuroplasticity following visual deprivation.