Sung Pyo Park
Columbia University Medical Center
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Publication
Featured researches published by Sung Pyo Park.
Korean Journal of Ophthalmology | 2014
Eun Jin Bae; Kyoung Rae Kim; Stephen H. Tsang; Sung Pyo Park; Stanley Chang
A 53-year-old Asian woman was treated with hydroxychloroquine and chloroquine for lupus erythematosus. Within a few years, she noticed circle-shaped shadows in her central vision. Upon examination, the patients visual acuity was 20 / 25 in both eyes. Humphrey visual field (HVF) testing revealed a central visual defect, and fundoscopy showed a ring-shaped area of parafoveal retinal pigment epithelium depigmentation. Fundus autofluorescence imaging showed a hypofluorescent lesion consistent with bulls eye retinopathy. Adaptive optics scanning laser ophthalmoscope (AO-SLO) revealed patch cone mosaic lesions, in which cones were missing or lost. In addition, the remaining cones consisted of asymmetrical shapes and sizes that varied in brightness. Unlike previous studies employing deformable mirrors for wavefront aberration correction, our AO-SLO approach utilized dual liquid crystal on silicon spatial light modulators. Thus, by using AO-SLO, we were able to create a photographic montage consisting of high quality images. Disrupted cone AO-SLO images were matched with visual field test results and functional deficits were associated with a precise location on the montage, which allowed correlation of histological findings with functional changes determined by HVF. We also investigated whether adaptive optics imaging was more sensitive to anatomical changes compared with spectral-domain optical coherence tomography.
Ophthalmic Surgery and Lasers | 2014
Sung Pyo Park; Winston Lee; Eun Jin Bae; Vivianne Greenstein; Bum Ho Sin; Stanley Chang; Stephen H. Tsang
The authors report the use of adaptive-optics scanning laser ophthalmoscopy (AO-SLO) to investigate RHO, D190N autosomal-dominant retinitis pigmentosa in two siblings (11 and 16 years old, respectively). Each patient exhibited distinct hyperautofluorescence patterns in which the outer borders corresponded to inner segment ellipsoid band disruption. Areas within the hyperautofluorescence patterns exhibited normal photoreceptor outer segments and retinal pigment epithelium. However, AO-SLO imaging revealed noticeable spacing irregularities in the cone mosaic. AO-SLO allows researchers to characterize retinal structural abnormalities with precision so that early structural changes in retinitis pigmentosa can be identified and reconciled with genetic findings.
European Journal of Human Genetics | 2013
Sung Pyo Park; In Hwan Hong; Stephen H. Tsang; Stanley Chang
X-linked retinitis pigmentosa (XLRP) is the least common genetic type of retinitis pigmentosa; however, it has extremely devastating consequences to patients’ activities of daily living. RPGR and RP2 genes expressed in the photoreceptor sensory cilia are predominantly implicated in XLRP; however, the interpretation of genetic mutations and their correlation with clinical phenotypes remain unknown, and the role of these genes in photoreceptor cilia function is not completely elucidated. Therefore, we evaluated structural characteristics in five female obligate carriers of XLRP by using state-of-the-art non-invasive imaging methods, including adaptive optics (AO) scanning laser ophthalmoscopy (SLO). In all five carriers examined, qualitative and quantitative analyses by AO SLO imaging revealed a mosaic pattern of cone disruption, even in the absence of visual symptoms, normal visual acuity and normal macular thickness, on optical coherence tomography and mildly subnormal full-field cone electroretinographic findings. As the technique is sensitive to the level of a single cone, the ability to visualize the cone cells in vivo should be especially useful in other retinal diseases. In addition, further investigation of XLRP carriers may yield insight into how cone structures change over time and ultimately enable understanding of the role of RPGR and RP2 in cone cell survival.
Ophthalmic Genetics | 2012
Sung Pyo Park; Stanley Chang; Rando Allikmets; R. Theodore Smith; Tomas R. Burke; Emily M. Gregory-Roberts; Stephen H. Tsang
Purpose: To describe the spectral domain-optical coherence tomography (SD-OCT) findings of two patients with complete defects in the retinal pigment epithelium (RPE) with disruptions in Bruch membrane in Stargardt disease (STGD1). Methods: Two patients with STGD1 were referred to our clinic for further evaluation. Fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), electroretinography (ERG) and Microperimetry (MP-1) were performed to assess the retinal anatomy and function. Screening for mutations in the ABCA4 gene was carried out and detected mutations were confirmed by direct sequencing. Results: Both patients had bilateral macular geographic atrophy (GA) and yellowish subretinal pisciform flecks and mutations were detected in the ABCA4 gene by chip screening. SD-OCT revealed marked atrophy of the retina in the central macula, with focal defects in the RPE with disruptions in Bruch membrane and herniation of the retina through the defect in three of four eyes. Conclusion: This case report highlights the necessity for a detailed ophthalmic examination including SD-OCT of patients with STGD1.
Ophthalmic Surgery and Lasers | 2014
In Hwan Hong; Sung Pyo Park; Ching Lung Chen; Hyoung Kyun Kim; Stephen H. Tsang; Stanley Chang
The authors report adaptive optics scanning laser ophthalmoscopy (AO-SLO) findings in a case of acute posterior multifocal placoid pigment epitheliopathy. The right eye showed an island of coarse, hyperreflective speckles surrounded by a dark annulus lacking cone cells, which were associated with reduced MP1 sensitivity and abnormal findings in other imaging modalities. Although dark lesions were also detected in the left eye, the correlated spectral-domain optical coherence tomography images were normal. AO-SLO allowed for the direct observation of retinal disruptions and the ability of this technology to detect abnormalities in the left eye demonstrates a superior ability for in-depth retinal imaging.
Ophthalmic Surgery and Lasers | 2013
Sung Pyo Park; Frank S. Siringo; Noelle Pensec; In Hwan Hong; Janet R. Sparrow; Gaetano R. Barile; Stephen H. Tsang; Stanley Chang
BACKGROUND AND OBJECTIVE To compare fundus autofluorescence (FAF) imaging via fundus camera (FC) and confocal scanning laser ophthalmoscope (cSLO). PATIENTS AND METHODS FAF images were obtained with a digital FC (530 to 580 nm excitation) and a cSLO (488 nm excitation). Two authors evaluated correlation of autofluorescence pattern, atrophic lesion size, and image quality between the two devices. RESULTS In 120 eyes, the autofluorescence pattern correlated in 86% of lesions. By lesion subtype, correlation rates were 100% in hemorrhage, 97% in geographic atrophy, 82% in flecks, 75% in drusen, 70% in exudates, 67% in pigment epithelial detachment, 50% in fibrous scars, and 33% in macular hole. The mean lesion size in geographic atrophy was 4.57 ± 2.3 mm(2) via cSLO and 3.81 ± 1.94 mm(2) via FC (P < .0001). Image quality favored cSLO in 71 eyes. CONCLUSION FAF images were highly correlated between the FC and cSLO. Differences between the two devices revealed contrasts. Multiple image capture and confocal optics yielded higher image contrast with the cSLO, although acquisition and exposure time was longer.
Experimental Eye Research | 2013
Sung Pyo Park; Jae Keun Chung; Vivienne C. Greenstein; Stephen H. Tsang; Stanley Chang
Investigative Ophthalmology & Visual Science | 2013
Sung Pyo Park; In Hwan Hong; Winston Lee; Marcela Marsiglia; Takeshi Kitamura; Stephen H. Tsang; Stanley Chang
Investigative Ophthalmology & Visual Science | 2013
Ching-Lung Chen; Sung Pyo Park; Takeshi Kitamura; Stanley Chang
Investigative Ophthalmology & Visual Science | 2013
Yong Jin Jeong; In Hwan Hong; Jae Keun Chung; Hyoung Kyun Kim; Sung Pyo Park