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Dive into the research topics where Chloe T. L. Khoo is active.

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Featured researches published by Chloe T. L. Khoo.


Retina-the Journal of Retinal and Vitreous Diseases | 2015

CORRELATION OF FOVEAL AVASCULAR ZONE SIZE WITH FOVEAL MORPHOLOGY IN NORMAL EYES USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

Wasim A. Samara; Emil Anthony T. Say; Chloe T. L. Khoo; Timothy Patrick Higgins; George Magrath; Sandor Ferenczy; Carol L. Shields

Purpose: To analyze the foveal avascular zone (FAZ) in normal eyes using optical coherence tomography angiography. Methods: Prospective noncomparative case series. The parafoveal region of 70 eyes from 67 healthy subjects was imaged using optical coherence tomography angiography to visualize the superficial and deep capillary plexuses and correlated with standard macular volume scans using spectral domain optical coherence tomography to determine foveal morphology. Results: In all 70 eyes imaged, 2 vascular plexuses could be detected within the retina: a superficial plexus within the ganglion cell layer and a deep plexus within the inner nuclear layer. A measurable FAZ was visualized in both plexuses in all imaged eyes. The FAZ area was variable in the study population with a mean of 0.266 mm2 ± 0.097 mm2 in the superficial plexus (range: 0.071 mm2–0.527 mm2) and a mean of 0.495 mm2 ± 0.227 mm2 in the deep plexus (range: 0.160 mm2–0.795 mm2). The FAZ area was significantly larger in the deep plexus (P < 0.0001) compared with superficial plexus. The FAZ area in both plexuses correlated inversely with central macular thickness and central macular volume (P < 0.0001). No significant correlation was found between superficial plexus FAZ area and age (P = 0.55) or sex (P = 0.34). In the same manner, no significant correlation was found between deep plexus FAZ area and age (P = 0.13) or sex (P = 0.13). Conclusion: Optical coherence tomography angiography provides a noninvasive method to visualize and measure the superficial and deep plexus FAZ in a normal population. The FAZ can vary in size and shape, with the FAZ area significantly larger in the deep compared with the superficial plexus. Both superficial and deep FAZ area correlate inversely with foveal thickness and volume.


Retina-the Journal of Retinal and Vitreous Diseases | 2016

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE MACULA AFTER PLAQUE RADIOTHERAPY OF CHOROIDAL MELANOMA: Comparison of Irradiated Versus Nonirradiated Eyes in 65 Patients.

Carol L. Shields; Emil Anthony T. Say; Wasim A. Samara; Chloe T. L. Khoo; Arman Mashayekhi; Jerry A. Shields

Purpose: To study radiation retinopathy after plaque radiotherapy of choroidal melanoma using optical coherence tomography angiography. Methods: Retrospective comparative analysis of 65 consecutive patients with choroidal melanoma, treated with standard dose I-125 plaque radiotherapy and imaged with optical coherence tomography angiography. A comparison of irradiated versus contralateral, nonirradiated (control) eyes was performed. Results: The mean patient age was 55 years. Underlying medical diseases included diabetes mellitus (4/65, 4%) or hypertension (25/65, 38%), but no patient demonstrated disease-related retinopathy. The mean pretreatment melanoma diameter was 11 mm and mean thickness was 5 mm. The mean radiation dose to the foveola was 5663 centiGray. At mean follow-up of 46 months after plaque radiotherapy, the most frequent qualitative finding on optical coherence tomography angiography (irradiated eye) was nonperfusion in the superficial capillary plexus (19/65, 29%) and deep capillary plexus (20/65, 31%), followed by loss of choriocapillaris within tumor margins (11/65, 17%). The quantitative findings revealed foveal avascular zone with significantly larger mean area (irradiated vs. nonirradiated eye) in the superficial plexus (0.961 vs. 0.280 mm2, P < 0.0001) and deep plexus (1.396 vs. 0.458 mm2, P < 0.0001), even in eyes without clinical evidence of radiation maculopathy (superficial 0.278 mm2, P = 0.03; deep 0.454 mm2, P = 0.02). Parafoveal capillary density (superficial and deep) was decreased in all irradiated eyes (P < 0.001). This difference was maintained after subgroup analysis of eyes with (P < 0.001) or without (P < 0.001) clinical evidence of radiation maculopathy. Mean logMAR visual acuity was significantly reduced in irradiated eyes (0.7 vs. 0.1 [Snellen equivalent 20/100 vs. 20/25], P < 0.001) and the reduced vision was significant even in eyes without clinical evidence of radiation maculopathy (0.4 vs. 0.1 [Snellen equivalent 20/50 vs. 20/25], P < 0.001). Conclusion: Optical coherence tomography angiography demonstrated significant enlargement of the foveal avascular zone and decreased parafoveal capillary density of both superficial and deep capillary plexuses in eyes after plaque radiotherapy of choroidal melanoma, even in eyes with no clinical evidence of radiation maculopathy.


Retina-the Journal of Retinal and Vitreous Diseases | 2017

IMAGE QUALITY AND ARTIFACTS ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: Comparison of Pathologic and Paired Fellow Eyes in 65 Patients With Unilateral Choroidal Melanoma Treated With Plaque Radiotherapy.

Emil Anthony T. Say; Sandor Ferenczy; George N. Magrath; Wasim A. Samara; Chloe T. L. Khoo; Carol L. Shields

Purpose: To study image quality and artifacts seen on optical coherence tomography angiography (OCTA). Methods: Sixty-five consecutive patients with unilateral posterior uveal melanoma treated with plaque radiotherapy had OCTA during follow-up. Optical coherence tomography angiography was performed on both the affected and fellow eye. Signal strength and frequency of image artifacts on en face images were compared between affected and fellow eyes. Results: A total of 130 eyes in 65 patients were analyzed, the mean age at time of OCTA was 55 years (median: 56, range: 12–81 years), and 39 (39/65, 60%) were female. Majority of tumors were located in the choroid (62/65, 95%) and extramacular (55/65, 85%). The mean distance to the foveola was 4 mm (median: 3, range: 0–18 mm) and optic nerve was 4 mm (median: 4, range: 0–16 mm). Optical coherence tomography angiography was performed at a mean 46 months after plaque radiotherapy. Most patients had a history of radiation maculopathy or papillopathy in the treated eye at the time of OCTA (46/65, 71%). Overall, 95 eyes (95/130, 73%) had at least one significant artifact on OCTA. The most common major artifacts were loss of focus (71/130, 55%), broad (>5 pixels width and >4 lines) blink lines (48/130, 37%), motion artifact (34/130, 26%), specular dot (33/130, 25%), and edge duplication (10/130, 8%). Statistically, eyes treated with plaque radiotherapy (affected vs. fellow eye) were more likely to have at least one major OCTA artifact (92 vs. 54%, P < 0.001) and, specifically, loss of focus was more frequent (78 vs. 31%, P < 0.001). Multivariate analysis found decreased visual acuity significantly associated with higher incidence of broad blink lines (P = 0.0166) and loss of signal (P < 0.0001), whereas male sex was associated with increased loss of signal (P = 0.0015), and distance to the foveola was related to edge duplication (P = 0.0119). Conclusion: Image artifacts on OCTA are commonly encountered and appear to be more frequent in eyes with pathology and poor visual acuity. Recognition of these artifacts might help improve image interpretation and decision making.


Ophthalmology | 2015

Juvenile Xanthogranuloma Involving the Eye and Ocular Adnexa: Tumor Control, Visual Outcomes, and Globe Salvage in 30 Patients

Wasim A. Samara; Chloe T. L. Khoo; Emil Anthony T. Say; Jarin Saktanasate; Ralph C. Eagle; Jerry A. Shields; Carol L. Shields

PURPOSE To report clinical features and treatment outcomes of ocular juvenile xanthogranuloma (JXG). DESIGN Retrospective case series. PARTICIPANTS There were 32 tumors in 31 eyes of 30 patients with ocular JXG. METHODS Review of medical records. MAIN OUTCOME MEASURES Tumor control, intraocular pressure (IOP), and visual acuity. RESULTS The mean patient age at presentation was 51 months (median, 15 months; range, 1-443 months). Eye redness (12/30, 40%) and hyphema (4/30, 13%) were the most common presenting symptoms. Cutaneous JXG was concurrently present in 3 patients (3/30, 10%), and spinal JXG was present in 1 patient (1/30, 3%). The ocular tissue affected by JXG included the iris (21/31, 68%), conjunctiva (6/31, 19%), eyelid (2/31, 6%), choroid (2/31, 6%), and orbit (1/31, 3%). Those with iris JXG presented at a median age of 13 months compared with 30 months for those with conjunctival JXG. In the iris JXG group, mean IOP was 19 mmHg (median, 18 mmHg; range, 11-30 mmHg) and hyphema was noted in 8 eyes (8/21, 38%). The iris tumor was nodular (16/21, 76%) or diffuse (5/21, 24%). Fine-needle aspiration biopsy was used in 10 cases and confirmed JXG cytologically in all cases. The iris lesion was treated with topical (18/21, 86%) and/or periocular (4/21, 19%) corticosteroids. The eyelid, conjunctiva, and orbital JXG were treated with excisional biopsy in 5 patients (5/9, 56%), topical corticosteroids in 2 patients (2/9, 22%), and observation in 2 patients (2/9, 22%). Of 28 patients with a mean follow-up of 15 months (median, 6 months; range, 1-68 months), tumor regression was achieved in all cases, without recurrence. Two patients were lost to follow-up. Upon follow-up of the iris JXG group, visual acuity was stable or improved (18/19 patients, 95%) and IOP was controlled long-term without medication (14/21 patients, 74%). No eyes were managed with enucleation. CONCLUSIONS Ocular JXG preferentially affects the iris and is often isolated without cutaneous involvement. Iris JXG responds to topical or periocular corticosteroids, often with stabilization or improvement of vision and IOP.


Retinal Cases & Brief Reports | 2017

INTRAARTERIAL CHEMOTHERAPY FOR RETINOBLASTOMA IN A 2-MONTH-OLD INFANT.

Tejal Magan; Chloe T. L. Khoo; Pascal Jabbour; Carol L. Shields

Purpose: Intraarterial chemotherapy for retinoblastoma is usually reserved for infants aged 3 months or older because of the intricacy of the newborn vascular anatomy making the procedure technically challenging. The authors report a successful case of intraarterial chemotherapy performed in a 2-month-old infant using a minimal exposure approach. Methods: Case report. Results: A 2-month-old infant presented with leukocoria and was subsequently diagnosed with an exophytic Group D retinoblastoma in the right eye. The infant received melphalan 3 mg delivered into the ostium of the ophthalmic artery of the right eye under fluoroscopic guidance. Examination under anesthesia a month later showed complete tumor regression to a calcified Type I scar. After a second cycle of intraarterial chemotherapy, no further treatment was necessary. There were no complications. Conclusion: Intraarterial chemotherapy is generally used for retinoblastoma in infants aged 3 months or older. The patient was successfully catheterized and treated at 2 months of age, with complete tumor regression after a single chemotherapy dose. Thus, in expert hands, intraarterial chemotherapy can be considered in such young infants.


Retina-the Journal of Retinal and Vitreous Diseases | 2016

PARAFOVEAL CAPILLARY DENSITY AFTER PLAQUE RADIOTHERAPY FOR CHOROIDAL MELANOMA: Analysis of Eyes Without Radiation Maculopathy.

Emil Anthony T. Say; Wasim A. Samara; Chloe T. L. Khoo; George N. Magrath; Priya Sharma; Sandor Ferenczy; Carol L. Shields

Purpose: To study the parafoveal capillary density using optical coherence tomography angiography (OCTA) in eyes treated with plaque radiotherapy. Research Design: Retrospective comparative case series. Participants: Ten patients treated with plaque radiotherapy for choroidal melanoma without evident radiation maculopathy on ophthalmoscopy or optical coherence tomography were imaged with OCTA. Main Outcome Measure: Comparison of the parafoveal capillary density in the superficial and deep capillary plexuses in the irradiated versus fellow nonirradiated eye. Results: Overall, mean patient age was 55 years (median: 57, range: 45–65 years), and majority were white (9/10, 90%) and female (9/10, 90%). No patient had diabetes mellitus, and 2 (2/10, 20%) had controlled systemic hypertension. The melanoma was located in the choroid in all patients (10/10, 100%), with 2 (2/10, 20%) in the macular region. The mean largest basal diameter was 11 mm (12, 6–16 mm), and mean thickness was 5 mm (5, 2–10 mm). Mean radiation dose to the tumor apex was 72 Gy (median: 70 Gy, range: 70–85 Gy). Mean foveolar radiation dose was 53 Gy (median: 35 Gy, range: 14–110 Gy). Mean follow-up duration after plaque radiotherapy was 17 months (median: 16 months, range: 5–39 months). There was no ophthalmoscopic evidence of radiation maculopathy throughout the follow-up in every case. Optical coherence tomography demonstrated normal foveal contour without edema or subretinal fluid in every case. On OCTA, there was no significant difference in signal strength (P = 0.1151), central macular thickness (P = 0.9316), and foveal avascular zone area in the superficial (P = 0.1595), and deep (P = 0.1534) capillary plexuses between the irradiated versus fellow eyes. However, there was a statistically significant decrease in capillary density in the parafoveal superficial (P = 0.0005) and deep (P = 0.0067) plexuses in the irradiated eye. In addition, mean logMAR visual acuity was 0.2 (0.1, 0.0–0.5) (Snellen equivalent 20/32) in the irradiated eye and 0.0 (0.0, range: 0.0–0.1) (Snellen equivalent 20/20) in the fellow eye (P = 0.0252). Conclusion: Optical coherence tomography angiography allows qualitative and quantitative analysis of parafoveal capillary density. After plaque radiotherapy for choroidal melanoma, in eyes with normal macular features on ophthalmoscopy and optical coherence tomography, there is a statistically significant decrease in parafoveal capillary density and logMAR visual acuity in irradiated eyes compared with fellow eyes. These subclinical ischemic findings represent the commencement of radiation maculopathy.


Journal of Pediatric Ophthalmology & Strabismus | 2015

Multimodal Imaging for Detection of Clinically Inapparent Diffuse Iris Juvenile Xanthogranuloma

Wasim A. Samara; Chloe T. L. Khoo; George Magrath; Carol L. Shields

A 6-month-old female infant was referred following three episodes of spontaneous hyphema. Iris juvenile xanthogranuloma was suspected but not clinically visible. Multimodal imaging with fluorescein angiography, anterior segment optical coherence tomography, and ultrasound biomicroscopy were used to detect the flat, transparent lesion and cytopathology confirmed juvenile xanthogranuloma.


Oman Journal of Ophthalmology | 2016

Flat choroidal melanoma masquerading as central serous chorioretinopathy.

Timothy Patrick Higgins; Chloe T. L. Khoo; George Magrath; Carol L. Shields

There are several mimickers of choroidal melanoma. We report a patient with recent family stress who developed blurred vision to 20/50 OD and was found to have unilateral central serous chorioretinopathy and a coincidental choroidal nevus. After 1 year without resolution of the subretinal fluid, the patient was referred for our opinion. On examination, visual acuity was 20/50 in the right eye and 20/20 in the left eye. The left eye was normal. Evaluation of the right eye showed a small, pigmented submacular choroidal lesion measuring 4 mm Χ 3 mm. Ultrasonography documented an isoechoic mass measuring 1.71 mm in thickness. Optical coherence tomography showed subretinal fluid with shaggy photoreceptors and hyper-reflective material within the subretinal fluid, likely indicative of lipofuscin within macrophages. Autofluorescence revealed orange pigment overlying the lesion. These features were strongly suggestive of small choroidal melanoma with five risk factors for tumor growth. Treatment with Iodine-125 plaque brachytherapy was performed on the patient. The readers should keep in mind that choroidal melanoma can manifest as a tiny choroidal mass with related multimodal imaging features of subretinal fluid and orange pigment.


Journal of Pediatric Ophthalmology & Strabismus | 2016

Intra-arterial Chemotherapy for Adult Onset Retinoblastoma in a 32-Year-Old Man.

Tejal Magan; Chloe T. L. Khoo; Pascal Jabbour; Dwain G Fuller; Carol L. Shields

A 32-year-old man with active unilateral group D retinoblastoma that was recurrent following external beam radiotherapy was treated with intra-arterial chemotherapy, leading to tumor regression. Additional plaque radiotherapy and intravitreal chemotherapy were required for complete control. Final visual acuity was 20/40. In selected cases, adult-onset retinoblastoma can be managed with intra-arterial chemotherapy. [J Pediatr Ophthalmol Strabismus. 2016;53:e43-e46.].


Ophthalmology | 2016

Subepidermal Calcified Nodule in the Periocular Region: A Report of 6 Cases

Carol L. Shields; Molly R. Marous; Mairghread G. Casey; Alexzandra M. Douglass; Chloe T. L. Khoo; Jurij R. Bilyk; Jerry A. Shields; Ralph C. Eagle

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Carol L. Shields

Thomas Jefferson University

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Wasim A. Samara

Thomas Jefferson University

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George Magrath

Thomas Jefferson University

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Jerry A. Shields

Thomas Jefferson University

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Sandor Ferenczy

Thomas Jefferson University

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George N. Magrath

Medical University of South Carolina

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Pascal Jabbour

Thomas Jefferson University

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Ralph C. Eagle

Thomas Jefferson University

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