Choi CJ, Chou JC, Lefebvre DR, Yoon MK. Margin Reflex Distance: Differences Based on Camera and Flash Positions. Ophthal Plast Reconstr Surg 2016;32(3):199-203.Abstract

PURPOSE: To evaluate the effect of camera flash position on the measurement of photographic margin reflex distances (MRD). METHODS: Subjects without any ophthalmic disease were prospectively enrolled after institutional review board approval. Clinical measurements of MRD1 and interpalpebral fissure were obtained. Photographs were then taken with a digital single lens reflex with built-in pop-up flash (dSLR-pop), a dSLR with lens-mounted ring flash (dSLR-ring), a point-and-shoot camera, and a smartphone, each in 4 positions: with the camera upright, rotated 90°, 180°, and 270°. The images were analyzed using ImageJ software to measure MRD1, interpalpebral fissure, horizontal white-to-white, and distance from nasal limbus to the corneal light reflex. RESULTS: Thirty-two eyes of 16 subjects were included (ages 27-65). When using the dSLR-ring, point-and-shoot, and smartphone, the difference between clinical and photographic MRD1 did not reach statistical significance. There was, however, a statistically significant difference in the upright position with dSLR-pop (mean difference 0.703 mm, σ = 0.984 mm, p = 0.0008). For dSLR-pop, photographic MRD1 in upright versus inverted position differed significantly (mean difference -0.562 mm, σ =0.348 mm, p < 0.0001). Photographic MRD1 between dSLR-pop and dSLR-ring showed significant difference in upright position (mean difference -0.572 mm, σ = 0.701 mm, p = 0.0002). There were no statistically significant differences between clinical and photographic interpalpebral fissure, and among white-to-white and nasal limbus to light reflex measurements in any position in all 4 cameras. CONCLUSIONS: When using photographs for measurement of MRD1, cameras with a near-coaxial light source and aperture have values that are most similar to clinical measurements.

Choi CJ, Peggy Chang H-Y, Lee NG. An Unusual Corneal Degeneration. JAMA Ophthalmol 2017;135(6):667-668.
Choi CJ, Bauza A, Yoon MK, Sobel RK, Freitag SK. Full-Thickness Skin Graft as an Independent or Adjunctive Technique for Repair of Cicatricial Lower Eyelid Ectropion Secondary to Actinic Skin Changes. Ophthal Plast Reconstr Surg 2015;31(6):474-7.Abstract

PURPOSE: To retrospectively review and describe full-thickness skin graft repair of lower eyelid cicatricial ectropion secondary to actinic skin. METHODS: A retrospective, noncomparative chart review of all patients who underwent lower eyelid ectropion repair with placement of a full-thickness skin graft between June 2004 and March 2014 was conducted with IRB approval. The etiology of lower eyelid ectropion, demographics including age, gender, ethnicity, laterality, graft donor site, additional surgical procedures, graft viability, surgical success rate, complications, and clinical exam findings were summarized. RESULTS: Twenty-nine eyelids in 24 patients underwent skin grafting for repair of cicatricial ectropion secondary to actinic skin changes. Ninety six percent of patients were male and 96% were Caucasian. Donor sites for skin grafts included upper eyelid (9, 31%), supraclavicular skin (9, 31%), postauricular skin (7, 24%), inner brachial skin (2, 7%), axilla (1, 3.5%), and preauricular skin (1, 3.5%). Twenty-four of 29 eyelids in the series underwent 1 or more additional procedures at the time of full-thickness skin grafting, including lateral tarsal strip (9 eyelids, 37.5%), punctoplasty (8, 33%), canthoplasty (7, 29%), excision of keratinized conjunctiva (2, 8%), transverse tarsotomy (1, 4%), ipsilateral external dacryocystorhinostomy (3, 12.5%), and lesion removal (1, 4%). There was 100% viability of the skin grafts. Overall surgical success rate was 76%, with asymptomatic recurrence rate of 17% and symptomatic recurrence rate of 7%. CONCLUSION: Repair of cicatricial lower eyelid ectropion secondary to actinic skin changes may be accomplished with full-thickness skin grafting, and is often performed in conjunction with additional procedures to fully address anatomic abnormalities.

Choi CJ, Lefebvre DR, Yoon MK. Validation of the facial assessment by computer evaluation (FACE) program for software-aided eyelid measurements. Orbit 2016;35(3):117-20.Abstract

The aim of this article is to validate the accuracy of Facial Assessment by Computer Evaluation (FACE) program in eyelid measurements. Sixteen subjects between the ages of 27 and 65 were included with IRB approval. Clinical measurements of upper eyelid margin reflex distance (MRD1) and inter-palpebral fissure (IPF) were obtained. Photographs were then taken with a digital single lens reflex camera with built-in pop-up flash (dSLR-pop) and a dSLR with lens-mounted ring flash (dSLR-ring) with the cameras upright, rotated 90, 180, and 270 degrees. The images were analyzed using both the FACE and ImageJ software to measure MRD1 and IPF.Thirty-two eyes of sixteen subjects were included. Comparison of clinical measurement of MRD1 and IPF with FACE measurements of photos in upright position showed no statistically significant differences for dSLR-pop (MRD1: p = 0.0912, IPF: p = 0.334) and for dSLR-ring (MRD1: p = 0.105, IPF: p = 0.538). One-to-one comparison of MRD1 and IPF measurements in four positions obtained with FACE versus ImageJ for dSLR-pop showed moderate to substantial agreement for MRD1 (intraclass correlation coefficient = 0.534 upright, 0.731 in 90 degree rotation, 0.627 in 180 degree rotation, 0.477 in 270 degree rotation) and substantial to excellent agreement in IPF (ICC = 0.740, 0.859, 0.849, 0.805). In photos taken with dSLR-ring, there was excellent agreement of all MRD1 (ICC = 0.916, 0.932, 0.845, 0.812) and IPF (ICC = 0.937, 0.938, 0.917, 0.888) values. The FACE program is a valid method for measuring margin reflex distance and inter-palpebral fissure.

Choi CJ, Oropesa S, Callahan AB, Glass LR, Teo L, Cestari DM, Kazim M, Freitag SK. Patterns of visual field changes in thyroid eye disease. Orbit 2017;36(4):201-207.Abstract
This article provides a systematic description of visual field changes in thyroid eye disease-compressive optic neuropathy (TED-CON). A retrospective, non-comparative chart review of patients with TED-CON and documented Humphrey Visual Field 24-2 or 30-2 testing was conducted with IRB approval. Ninety-six visual fields in 68 patients were classified into 7 broad categories (superior, inferior, diffuse, temporal, nasal, central/paracentral, enlarged blind spot) and 17 mutually exclusive patterns from the Ocular Hypertension Treatment Study (OHTS) or "other." Fifty-three of 96 visual fields (55%) showed an inferior defect using the broad categories, with the remaining 6 categories ranging from 2% to 14%. The five most common OHTS patterns were other (28%), partial arcuate (28%), partial peripheral rim (9%), arcuate (8%) and altitudinal (7%). Further sub-classification showed a predominance of inferior visual field defects, ranging from 33% to 93% of each category. Of the 78 visual fields in these five categories combined, 52 (67%) were inferior defects. Inferior defect is the most typical TED-CON-associated visual field change. While the OHTS categories are geared toward classification of glaucomatous patterns, the overall predominance of inferior field defects in TED-CON was clearly demonstrated. These "other" visual field changes showing central inferior defect up to but not crossing the horizontal meridian and not contiguous from blind spot to nasal meridian should be designated as "TED-CON pattern." The high proportion of visual fields falling under the "other" category, however, does demonstrate the need for a more specific and tailored visual field classification system for TED-CON.
Choi W, Byun YJ, Jung E, Noh H, Hajrasouliha AR, Sadrai Z, Chang EJ, Lee JH, 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.Abstract

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.

Choi VW, Bigelow CE, McGee TL, Gujar AN, Li H, Hanks SM, Vrouvlianis J, Maker M, Leehy B, Zhang Y, Aranda J, Bounoutas G, Demirs JT, Yang J, Ornberg R, Wang Y, Martin W, Stout KR, Argentieri G, Grosenstein P, Diaz D, Turner O, Jaffee BD, Police SR, Dryja TP. AAV-mediated RLBP1 gene therapy improves the rate of dark adaptation in Rlbp1 knockout mice. Mol Ther Methods Clin Dev 2015;2:15022.Abstract

Recessive mutations in RLBP1 cause a form of retinitis pigmentosa in which the retina, before its degeneration leads to blindness, abnormally slowly recovers sensitivity after exposure to light. To develop a potential gene therapy for this condition, we tested multiple recombinant adeno-associated vectors (rAAVs) composed of different promoters, capsid serotypes, and genome conformations. We generated rAAVs in which sequences from the promoters of the human RLBP1, RPE65, or BEST1 genes drove the expression of a reporter gene (green fluorescent protein). A promoter derived from the RLBP1 gene mediated expression in the retinal pigment epithelium and Müller cells (the intended target cell types) at qualitatively higher levels than in other retinal cell types in wild-type mice and monkeys. With this promoter upstream of the coding sequence of the human RLBP1 gene, we compared the potencies of vectors with an AAV2 versus an AAV8 capsid in transducing mouse retinas, and we compared vectors with a self-complementary versus a single-stranded genome. The optimal vector (scAAV8-pRLBP1-hRLBP1) had serotype 8 capsid and a self-complementary genome. Subretinal injection of scAAV8-pRLBP1-hRLBP1 in Rlbp1 nullizygous mice improved the rate of dark adaptation based on scotopic (rod-plus-cone) and photopic (cone) electroretinograms (ERGs). The effect was still present after 1 year.

Choi CJ, Stagner AM, Jakobiec FA, Lee NG. Limbal Mantle Cell Lymphoma of the Conjunctiva. Ophthalmology 2016;123(2):377.
Choi CJ, Jakobiec FA, Zakka FR, Sanchez AV, Lee NG. Ocular Surface Squamous Neoplasia in a Patient With Hepatitis C. JAMA Ophthalmol 2017;135(10):1121-1123.
Choi HJ, Sun D, Jakobs TC. Astrocytes in the optic nerve head express putative mechanosensitive channels. Mol Vis 2015;21:749-66.Abstract

PURPOSE: To establish whether optic nerve head astrocytes express candidate molecules to sense tissue stretch. METHODS: We used conventional PCR, quantitative PCR, and single-cell reverse transcription PCR (RT-PCR) to assess the expression of various members of the transient receptor potential (TRP) channel family and of the recently characterized mechanosensitive channels Piezo1 and 2 in optic nerve head tissue and in single, isolated astrocytes. RESULTS: Most TRP subfamilies (TRPC, TRPM, TRPV, TRPA, and TRPP) and Piezo1 and 2 were expressed in the optic nerve head of the mouse. Quantitative real-time PCR analysis showed that TRPC1, TRPM7, TRPV2, TRPP2, and Piezo1 are the dominant isoforms in each subfamily. Single-cell RT-PCR revealed that many TRP isoforms, TRPC1-2, TRPC6, TRPV2, TRPV4, TRPM2, TRPM4, TRPM6-7, TRPP1-2, and Piezo1-2, are expressed in astrocytes of the optic nerve head, and that most astrocytes express TRPC1 and TRPP1-2. Comparisons of the TRPP and Piezo expression levels between different tissue regions showed that Piezo2 expression was higher in the optic nerve head and the optic nerve proper than in the brain and the corpus callosum. TRPP2 also showed higher expression in the optic nerve head. CONCLUSIONS: Astrocytes in the optic nerve head express multiple putative mechanosensitive channels, in particular the recently identified channels Piezo1 and 2. The expression of putative mechanosensitive channels in these cells may contribute to their responsiveness to traumatic or glaucomatous injury.

Choi HJ, Sun D, Jakobs TC. Isolation of intact astrocytes from the optic nerve head of adult mice. Exp Eye Res 2015;137:103-10.Abstract

The astrocytes of the optic nerve head are a specialized subtype of white matter astrocytes that form the direct cellular environment of the unmyelinated ganglion cell axons. Due to their potential involvement in glaucoma, these astrocytes have become a target of research. Due to the heterogeneity of the optic nerve tissue, which also contains other cell types, in some cases it may be desirable to conduct gene expression studies on small numbers of well-characterized astrocytes or even individual cells. Here, we describe a simple method to isolate individual astrocytes. This method permits obtaining astrocytes with intact morphology from the adult mouse optic nerve and reduces contamination of the isolated astrocytes by other cell types. Individual astrocytes can be recognized by their morphology and collected under microscopic control. The whole procedure can be completed in 2-3 h. We also discuss downstream applications like multiplex single-cell PCR and quantitative PCR (qPCR).

Chou J, Daly MK. Reply. Retina 2017;37(10):e118.
Chou JC, Cousins CC, Miller JB, Song BJ, Shen LQ, Kass MA, Wiggs JL, Pasquale LR. Fundus Densitometry Findings Suggest Optic Disc Hemorrhages in Primary Open-Angle Glaucoma Have an Arterial Origin. Am J Ophthalmol 2018;Abstract
PURPOSE: To analyze optic disc hemorrhages (DH) associated with primary open-angle glaucoma by quantifying their geometric profile and comparing their densitometry with hemorrhages from retinal vein occlusions (RVO) and retinal macroaneurysms (MA), which have venous and arterial sources of bleeding, respectively. DESIGN: Retrospective cross-sectional study METHODS: Setting: Massachusetts Eye & Ear POPULATION: Fundus images of DH (n=40), MA (n=14), and RVO (n=25) were identified. Patient clinical backgrounds and demographics were obtained. MAIN OUTCOME: Grayscale pixel intensity units of hemorrhages and adjacent arteriole and venule over the same background tissue were measured. Densitometry differentials (arteriole or venule minus hemorrhage [ΔA and ΔV, respectively]) were calculated. The ratios of length (radial) to midpoint width for DH were calculated. T-tests compared mean ΔA and ΔV between groups. Multiple linear regression assessed the relation of retinal hemorrhage diagnosis to ΔA and ΔV and of DH shape to ΔA and ΔV. RESULTS: Mean (±standard deviation) ΔA and ΔV for DH (6.9±7.1 and -4.7±8.0 pixel intensity units, respectively) and MA (5.3±5.9 and -6.0±4.6, respectively) were comparable (P≥0.43). Mean ΔA (14.6±7.7) and ΔV (6.4±6.3) for RVO were significantly higher compared to DH and MA (P<0.0001) and remained significant in multivariable analyses. A unit increase in DH length-to-width ratio was associated with 1.2 (0.5) and 1.3 (0.5) pixel intensity unit (standard error) decrease in ΔA and ΔV, respectively (P≤0.014). CONCLUSIONS: DH have densitometry profiles comparable to MA and different from RVO, suggesting that DH in glaucoma have an arterial origin.
Chou J, Kosowsky T, Payal AR, Gonzalez Gonzalez LA, Daly MK. CONSTRUCT AND FACE VALIDITY OF THE EYESI INDIRECT OPHTHALMOSCOPE SIMULATOR. Retina 2017;37(10):1967-1976.Abstract
PURPOSE: To evaluate construct and face validity of the Eyesi Binocular Indirect Ophthalmoscope Simulator. METHODS: The performance of 25 medical students (Group A) was compared with that of 17 ophthalmology and optometry trainees (Group B) on the Eyesi Binocular Indirect Ophthalmoscope Simulator. During the course of a single session, each participant viewed an orientation module followed by an instruction session and a demonstration case, and performed 6 cases of progressively increasing difficulty (4 levels) and a 10-question face validity questionnaire. Outcomes included total score, total examination time, percent retina examined, and duration of eye exposure to light. RESULTS: Group B achieved significantly better total scores than Group A on all difficulty levels (P = 0.02, P = 0.001, P = 0.001, and P = 0.0001, for Levels 1-4, respectively) and had a significantly faster mean duration of examination (8 minutes 58 seconds vs. 5 minutes 21 seconds, P < 0.0001). Medical students reported higher scores in the face validity questionnaire for the simulator experience being helpful at orienting them to true indirect ophthalmology, and that further training on the simulator would improve their skills in the clinic (P = 0.03 for all). CONCLUSION: The Eyesi Binocular Indirect Ophthalmoscope Simulator has significant construct and face validity and shows promise for medical education.
Chronopoulos A, Roy S, Beglova E, Mansfield K, Wachtman L, Roy S. Hyperhexosemia-induced retinal vascular pathology in a novel primate model of diabetic retinopathy. Diabetes 2015;Abstract

The paucity of animal models exhibiting full pathology of diabetic retinopathy (DR) has impeded understanding of the pathogenesis of DR and the development of therapeutic interventions. Here we investigated if hyperhexosemic marmosets (Callithrix jacchus) develop characteristic retinal vascular lesions including macular edema (ME), a leading cause of vision loss in DR. Marmosets maintained on 30% galactose (gal)-rich diet for two years were monitored for retinal vascular permeability, development of ME, and morphological characteristics including acellular capillaries (AC) and pericyte loss (PL), vessel tortuosity, and capillary basement membrane (BM) thickness. Excess vascular permeability, increased number of AC and PL, vascular BM thickening, and increased vessel tortuosity were observed in the retinas of gal-fed marmosets. Optical coherence tomography (OCT) images revealed significant thickening of the retinal foveal and the juxtafoveal area, and histological analysis showed incipient microaneurysms in retinas of gal-fed marmosets. Findings from this study indicate that hyperhexosemia can trigger retinal vascular changes similar to those seen in human DR including ME and microaneurysms. The striking similarities between the marmoset retina and the human retina, and the exceptionally small size of the monkey, offer significant advantages to this primate model of DR.

Chuck RS, Jacobs DS, Lee JK, Afshari NA, Vitale S, Shen TT, Keenan JD, of Panel AAOPPPRM/I. Refractive Errors & Refractive Surgery Preferred Practice Pattern®. Ophthalmology 2018;125(1):P1-P104.
Chun BY, Cestari DM. Advances in experimental optic nerve regeneration. Curr Opin Ophthalmol 2017;28(6):558-563.Abstract
PURPOSE OF REVIEW: Recent advances in experimental studies of optic nerve regeneration to better understand the pathophysiology of axon regrowth and provide insights into the future treatment of numerous optic neuropathies. RECENT FINDINGS: The optic nerve is part of the central nervous system and cannot regenerate if injured. There are several steps that regenerating axons of retinal ganglion cells (RGCs) must take following optic nerve injury that include: maximizing the intrinsic growth capacity of RGCs, overcoming the extrinsic growth-inhibitory environment of the optic nerve, and optimizing the reinnervation of regenerated axons to their targets in the brain. Recently, some degree of experimental optic nerve regeneration has been achieved by factors associated with inducing intraocular inflammation, providing exogenous neurotrophic factors, reactivating intrinsic growth capacity of mature RGCs, or by modifying the extrinsic growth-inhibitory environment of the optic nerve. In some experiments, regenerating axons have been shown to reinnervate their central targets in the brain. SUMMARY: Further approaches to the combination of aforementioned treatments will be necessary to develop future therapeutic strategy to promote ultimate regeneration of the optic nerve and functional vision recovery after optic nerve injury.
Chun BY, Rizzo JF. Dominant optic atrophy: updates on the pathophysiology and clinical manifestations of the optic atrophy 1 mutation. Curr Opin Ophthalmol 2016;Abstract

PURPOSE OF REVIEW: Review recent advances in clinical and experimental studies of dominant optic atrophy (DOA) to better understand the complexities of pathophysiology caused by the optic atrophy 1 (OPA1) mutation. RECENT FINDINGS: DOA is the most commonly diagnosed inherited optic atrophy, causing progressive bilateral visual loss that begins early in life. During the past 25 years, there has been substantial progress in the understanding of the clinical, genetic, and pathophysiological basis of this disease. The histopathological hallmark of DOA is the primary degeneration of retinal ganglion cells, preferentially in the papillomacular bundle, which results temporal optic disc pallor and cecocentral scotomata in patients with DOA. Loss of OPA1 protein function by OPA1 gene mutations causes mitochondrial dysfunction because of the loss of mitochondrial fusion, impaired mitochondrial oxidative phosphorylation, increases in reactive oxygen species, and altered calcium homeostasis. These factors lead to apoptosis of retinal ganglion cells by a haploinsufficiency mechanism. SUMMARY: Improved understanding of the pathophysiology of DOA provides insights that can be used to develop therapeutic approaches to the DOA.

Chwalisz B, Gilbert AL, Gittinger JW. Perioperative Vision Loss after Non-Ocular Surgery. Semin Ophthalmol 2017;:1-6.Abstract
Perioperative vision loss (POVL) may cause devastating visual morbidity. A prompt anatomical and etiologic diagnosis is paramount to guide management and assess prognosis. Where possible, steps should be undertaken to minimize risk of POVL for vulnerable patients undergoing high-risk procedures. We review the specific risk factors, pathophysiology, and management and prevention strategies for various etiologies of POVL.
Chwalisz BK, Bouffard MA, Prasad S, Cestari DM. Neuroimaging diagnostic and monitoring approaches in ophthalmology. Curr Opin Neurol 2017;Abstract
PURPOSE OF REVIEW: We review new applications of optical coherence tomography (OCT) technology in neuro-ophthalmology. We also describe new technologies for visualizing the extracranial vessels in the diagnosis of giant cell arteritis (GCA). RECENT FINDINGS: Newer OCT modalities are expanding the evaluation of the optic disc, and are being applied to a number of neurologic conditions such as demyelinating and neurodegenerative disease. Swept-source OCT and enhanced-depth imaging OCT are refining the fine-grained analysis of the optic nerve head in the diagnosis of papilledema and optic nerve drusen. OCT-angiography is opening up new avenues to the study of the vasculature of the optic nerve head and its disorders, including ischemic optic neuropathy. Newer technologies in the diagnosis of GCA include vascular ultrasound, magnetic resonance imaging (MRI) of the extracranial vasculature and PET imaging of the large vessels. SUMMARY: OCT and several of its derivations are advancing diagnosis, and in some cases prognostication, in a variety of inflammatory, ischemic and compressive optic neuropathies. These technologies hold potential in the laboratory as well, yielding insights into the mechanisms of a variety of neurological conditions. In addition, further developments in MRI and ultrasonography techniques are shaping the approach to the diagnosis of GCA.