• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.151-155
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• 2014

Although various ophthalmic imaging methods, including fundus photography and optical coherence tomography, have been applied for effective diagnosis of ocular diseases with high spatial resolution, most of them are limited by shallow imaging penetration depth and a narrow field of view. Also, many of those imaging modalities are optimized to provide microscopic anatomical information, while functional or cellular information is lacking. Compared to other ocular imaging modalities, photoacoustic imaging can achieve relatively deep penetration depth and provide more detailed functional and cellular data based on photoacoustic signal generation from endogenous contrast agents such as hemoglobin and melanin. In this paper, array-based ultrasound and photoacoustic imaging was demonstrated to visualize pigmentation in the eye as well as overall ocular structure. Fresh porcine eyes were visualized using a real-time ultrasound micro-imaging system and an imaging probe supporting laser pulse delivery. In addition, limited photoacoustic imaging field of view was improved by an imaging probe tilting method, enabling visualization of most regions of the retina covered in the ultrasound imaging.

• Journal of Veterinary Clinics
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• v.37 no.5
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• pp.282-285
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• 2020

A 14-year-old neutered-male Shih-Tzu was referred for glaucoma and hyphema accompanied by systemic hypertension. After topical corticosteroid and antiglaucoma medications, the left eye (OS) progressed phthisically, but ocular hypertension redevelop one-year-and-seven-months later. Suspected limbal melanoma developed in peripheral cornea/limbal sclera with heavily pigmented cornea OS. Ultrasound biomicroscopy and ocular ultrasonography differentiated ciliary body origin-heterogeneous mass from limbal mass. Persistent hyphema and pigmented cornea might obscure intraocular lesion and advanced diagnostic methods played a crucial role. Unlike the generally benign limbal melanoma, aggressive treatment was recommended for uveal tumor. Histopathology of enucleated OS confirmed malignant uveal melanoma with chronic hypertensive vasculopathy.

• Current Optics and Photonics
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• v.2 no.1
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• pp.59-68
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• 2018

Opto-acoustic systems provide structural and functional information regarding biological tissues. Conventional opto-acoustic systems typically employ continuous or pulsed lasers as transmission sources. Compared to lasers, light emitting diodes (LEDs) are cost-effective and relatively portable excitation sources but are non, coherent. Therefore, in this study, a relatively low cost lens - a type of Ramsden eyepiece - was specially designed to theoretically calculate the illumination and achieve a constant brightness across the pupil of an eye. In order to verify the capability of the developed light-emitting diode-acoustic (LEDA) systems, we carried out experiments on bovine and bigeye tuna eyeball samples, which are of similar size to the human eye, using low frequency (10 MHz) and high frequency (25 MHz) ultrasound transducers. High frequency ultrasound transducers are able to provide higher spatial resolution compared to low frequency ultrasound transducers at the expense of penetration depth. Using the 10 MHz and 25 MHz ultrasound transducers, acceptable echo signals (3.82, 3.94, and 5.84 mV at 10 MHz and 282, 1557, 2356 mV at 25 MHz) from depth greater than 3 cm and 6 cm from the anterior surface of the eye were obtained. We thereby confirmed that the LEDA system using a pulsed LED with the designed Ramsden eyepiece lens, used in conjunction with low and high frequency ultrasound transducers, has the potential to be a cost-effective alternative method, while providing adequate acoustic signals from bovine and bigeye tuna ocular areas.

• Journal of Veterinary Science
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• v.22 no.2
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• pp.22.1-22.9
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• 2021

Background: Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). Objective: To describe a technique for USG PB in horse cadavers. Methods: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised to two operators naive to the USG PB, with moderate experience with ultrasonography and conventional "blind" RB. Both techniques were demonstrated once. Subsequently, operators performed five USG PB and five RB each, unassisted. Contrast location and spread were evaluated by CT. Injection site success was defined for USG PB as extraconal contrast, and for RB intraconal contrast. Results: Success was 10/10 for USG PB and 0/10 for RB (p < 0.001). Of the RB injections, eight resulted in extraconal contrast and two in the masseter muscle (p = 0.47). Conclusions: The USG PB had a high injection site success rate compared with the RB technique; however, we cannot comment on clinical effect. The USG technique was easily learnt, and no potential complications were seen. The USG PB nerve block could have a wide application for use in horses for ocular surgeries (enucleations, eyelid, corneal, cataract surgeries, and ocular analgesia) due to reduced risk of iatrogenic damage. Further clinical studies are needed.

• Journal of Veterinary Clinics
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• v.33 no.1
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• pp.65-69
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• 2016

A 10-year-9-month-old spayed female Shih Tzu was presented with ocular discharge and corneal opacity to Veterinary Medical Teaching Hospital of Seoul National University. Complete ophthalmic examination revealed bilateral keratoconjunctivitis sicca accompanied by the severe corneal neovascularization and edema in the right eye (OD). Ultrasound biomicroscopy incidentally showed an iridociliary mass located at 6~7 o'clock in the OD. No evidence of metastasis was observed on thoracic and abdominal radiography. Enucleation was selected and performed on the OD, considering the risk of metastasis or recurrence. Non-invasive and pigmented iridociliary adenoma was confirmed on histopathological evaluation.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.315-318
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• 2018

A 13-year-old spayed female Beagle dog was referred with high intraocular pressure, hyperemia, and exophthalmos of the left eye and underwent ultrasound, which revealed a mass in the ciliary body of the left eye. Magnetic resonance (MR) imaging was ordered to evaluate invasion of surrounding structures and metastasis to the brain via the optic nerve. On MR imaging, a single, well-defined, smoothly marginated, triangular-to-oval-shaped mass was found. The mass was hyperintense on T1-weighted images and hypointense on T2-weighted images, similar to a previous case of ocular melanoma. The mass originated from the ciliary body and extended from the anterior chamber to the posterior chamber. Slight enhancement was observed in the mass. There was no evidence of invasion into surrounding structures or the optic nerve, and no sign of metastasis to the brain. The mass was histopathologically diagnosed as benign uveal melanocytoma.

• Journal of Veterinary Clinics
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• v.30 no.2
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• pp.131-133
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• 2013

A 9-year-old, intact female Jindo dog weighing 23 kg was presented to the Veterinary Medical Teaching Hospital of Chungnam National University with a history of two months of ocular discharge. Initial ocular examination showed a 2 cm elongated mass arising from the ventral bulbar conjunctiva of the left eye. Ocular ultrasound, performed to rule out any orbital and intraocular involvement, was negative. Thoracic radiographs and abdominal ultrasonography revealed no abnormalities. Fine needle aspiration (FNA) of mass was performed. Aspiration cytology showed the presence of a round cell population mostly characterized. A moderate amount of eosinophils was present among round cells. The mass was excised and identified hitologically as a mast cell tumor. Six months after surgical treatment, thoracic radiographs and abdominal ultrasonography did not reveal any clinical signs of local recurrence or metastatic disease.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.152-157
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• 2023

A two-year-old, spayed female, Bichon Frise, was referred for severe corneal edema and corneal ulcer in the left eye (OS). The cornea had gradually swelled over one week after phacoemulsification performed a month prior, and that was refractory to 5% sodium chloride eye drop instillation or temporary partial tarsorrhaphy. A complete ophthalmic examination was performed. Severe corneal edema with intrastromal bullae and moderate anterior chamber flare was found on slit-lamp biomicroscopy in the OS, which obstructed the fundus examination. Corneal thickness was measured using high-resolution ultrasound biomicroscopy. The thickness of the OS cornea was 2.74 mm. The "letter-box" conjunctival flap was planned. Dorsal and ventral superficial keratectomy followed by a hood conjunctival flap was performed. Topical and systemic antibiotics and 5% sodium chloride eye drops were prescribed. Decreased corneal thickness was observed at one week, two weeks, and two months postoperatively (1.53 mm, 1.32 mm, and 0.92 mm, respectively). There were no postoperative complications, such as ocular discomfort or recurrent corneal ulcers. The "letter-box" conjunctival flap, a type of superficial keratectomy and conjunctival advancement hood flap, effectively relieved the severe irreversible corneal edema. This could be a simple but effective surgical intervention for patients with endothelial cell damage especially after phacoemulsification.

• Journal of Veterinary Clinics
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• v.35 no.5
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• pp.233-236
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• 2018

A 13-year-old spayed female Beagle dog was referred with high intraocular pressure, hyperemia, and exophthalmos of the left eye and underwent ultrasound, which revealed a mass in the ciliary body of the left eye. Magnetic resonance (MR) imaging was ordered to evaluate invasion of surrounding structures and metastasis to the brain via the optic nerve. On MR imaging, a single, well-defined, smoothly marginated, triangular-to-oval-shaped mass was found. The mass was hyperintense on T1-weighted images and hypointense on T2-weighted images, similar to a previous case of ocular melanoma. The mass originated from the ciliary body and extended from the anterior chamber to the posterior chamber. Slight enhancement was observed in the mass. There was no evidence of invasion into surrounding structures or the optic nerve, and no sign of metastasis to the brain. The mass was histopathologically diagnosed as benign uveal melanocytoma.

• Journal of Veterinary Clinics
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• v.31 no.4
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• pp.344-349
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• 2014

A 5-year-old intact female Maltese, a 4-year-old neutered male Chihuahua, and a 5-year-old neutered male Maltese were referred to Veterinary Medical Teaching Hospital of Seoul National University for assessment of traumatic corneal laceration accompanied by anterior lens capsule disruption by cat claw. Severe uveitis, hypopyon, fibrinous exudate, diffuse corneal edema, and/or glaucoma were observed. B-mode ocular ultrasound showed lens capsule rupture and hyperechoic lens in all three cases. Despite aggressive treatments, the three eyes continued to deteriorate with endophthalmitis, leading to enucleation. Septic implantation syndrome associated with phakitis, severe pyogranulomatous endophthalmitis, and keratitis was confirmed by histopathological examination.