• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.97-106
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• 2011

Purpose: This review article was written to theoretically compare the depressing force (pressure, adhesion) to the cornea between when the spherical lenses were being tightly and flat fitted. Methods: Mathematical equations and their numerical solution programs (model) were formulated to calculate the depressing (adhesion) force to the cornea by both the tightly and flat fitted contact lenses. Based on this proposed model the effects of parameters characterizing a contact lens such as BCs, diameters, edge shape and corneal shape (ratio of long and short corneal axis, p) on the depressing force to the cornea were predicted/analyzed in both tightly and flat fitting regimes. Results: Corneal adhesion increased as the corneal p-value increased. Adhesion increase caused by the increased p-value was much larger in flat fitted case than in tight fitted one. Corneal adhesion reduced abruptly as the BC increased in flat fitting regimes while the adhesion rise was insignificant in tight fitting ones. Reduction in corneal adhesion due to lens-size increase was predicted to be insignificant in both tight and flat fitting regimes. Both the lens edge shape (edge angle) and thickness were relevant only in tight fitting regime. Corneal adhesion increased as the increased with tight-fitted lenses. As the thickness of tight fitted lenses increased, corneal adhesion inversely decreased. Conclusions: The two most significantly affecting the depressing force to cornea were found to be the degree of corneal bending toward the periphery and the BCs of lenses.

• Journal of Veterinary Science
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• v.24 no.2
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• pp.30.1-30.6
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• 2023

A 4-year-old Chihuahua dog was referred for bilateral corneal ulcers. Slightly raised white fluorescein-positive plaque-like corneal lesions in both eyes appeared as intense hyperreflective areas with posterior shadowing on optical coherence tomography (OCT). Based on corneal cytology and culture, Candida albicans-induced fungal keratitis was diagnosed. Despite treatment, on OCT, endothelial plaques, increased stromal infiltration thickness, vertical shapes of the ulcer edge, and necrotic stromal space were judged to be aggravation of the disease, and surgery was performed. Conjunctival grafting surgery with topical 1% voriconazole effectively resolved fungal keratitis. OCT can provide detailed and objective information related to the disease prognosis.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1115-1122
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• 2018

Purpose: To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age. Materials and Methods: In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method. Results: This study included 217 eyes of 118 participants (20-81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participant's age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20-44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased CorvisIOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20-44 years, and over 44 years). Conclusion: We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.

• Medical Lasers
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• v.10 no.1
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• pp.22-30
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• 2021

Background and Objectives Ocular alkali burns cause severe damage to the ocular tissues and vision loss. Solcoseryl is a standardized calf blood extract that normalizes the metabolic disturbance and aids in maintaining the chemical and hormonal balance and has been used to treat burns in various tissues. This study examined the effects of Solcoseryl on a rat corneal alkali burn model. Materials and Methods Twenty rats were assigned randomly to four equal groups, including alkali burn, hyaluronic acid, Solcoseryl eyedrop, and Solcoseryl gel. A corneal alkali burn was induced by a NaOH-soaked paper disc. The treatments were given twice a day, every day. The wound area was measured after 24 and 48 hours, and the degree of neovascularization and corneal opacity were scored every week. The rats were sacrificed after three weeks for immunohistochemistry (IHC) to compare the level of inflammatory cytokines, IL-1β, IL-6, and TNF-α. The thickness of the retinal layers was compared to observe any changes in the retina. Results The use of Solcoseryl on corneal alkali burn accelerated wound healing with less neovascularization, greater opacity, and less cataract. IHC showed that the inflammation of the cornea was controlled by both the hyaluronic acid and Solcoseryl treatments. On the other hand, the inflammation had spread to the retina. When the dosage forms were compared, eyedrops were more effective on corneal inflammation, while the gel-type had a greater effect on retinal inflammation. Conclusion Solcoseryl was effective in accelerating the wound healing rate on a corneal alkali burn but could not prevent the spread of inflammation from the cornea to the retina. Eyedrops were more effective on inflammation in the cornea, and the gel was more effective in the retina.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.293-297
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• 2011

Purpose: This study was to know the correlation among refractive error and the dimensions of ocular components on older adults. Methods: The subjects were 95 older age who had no eye diseases. The refractive error, corneal radius, corneal diopter, axial length, anterior chamber depth and lens thickness were measured and analysed. Results: The axial length(AL)/corneal radius(CR) ratio was positively correlated with the corneal diopter, axial length, the anterior chamber depth. Then it was negatively correlated with corneal radius. It was shown that the highest correlation was between the corneal diopter and axial length (r = -0.545, p = 0.000). The spherical equivalent of the refractive error was negatively correlated with the AL/CR ratio. Conclusions: It was shown that the AL/CR ratio was a very important indicator for diagnosing the refractive error of the old age.

• Journal of the Korea society of information convergence
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• v.6 no.1
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• pp.37-41
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• 2013

In this study, by using the Oculus Pentacam, we analyzed the relationship of corneal front astigmatism corneal and the radius of curvature of the rear face of the 20's to 40's. The vertical radius of curvature were man 7.94mm (${\pm}0.22$), women 7.87mm (${\pm}0.21$), the horizontal radius of the anterior corneal appeared man 7.69mm (${\pm}0.27$), women 7.63mm(${\pm}0.23$). And rear vertical radius of curvature were man 6.52mm(${\pm}0.23$), woman 6.55mm (${\pm}0.22$), the horizontal radius of the anterior corneal appeared man 6.06mm (${\pm}0.24$), woman 6.08mm(${\pm}0.24$). The results of correlation analysis between the radius of corneal posterior surface and the anterior corneal surface, it was found out that there is a significant correlation. In this study, similar results were obtained anterior surface of the cornea, the radius of curvature of the rear surface, the refractive power, and astigmatism, as other papers that have been reported. But in this paper, the cornea thickness was thicker than other previously reported paper.

• Journal of Veterinary Clinics
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• v.30 no.1
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• pp.41-44
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• 2013

A 4-year-old castrated male Shih-Tzu was presented to the Chonbuk National University Animal Medical Center with a history of melting ulcer in the right eye (OD). Upon ophthalmologic examination, severe keratomalacia of approximately 70% of the entire surface area with a full thickness corneal defect was found in OD. In addition, iris and fibrin clots were observed on the center of the corneal defect. The menace response and dazzle reflex were normal in OS. As the size and damage of corneal perforation was so severe, amniotic membrane (AM) transplantation was considered to repair the cornea instead of direct suture technique, flap methods or corneal transplantation. Equine AM was sutured to the limbus to cover the entire cornea in a single interrupted pattern using 9-0 nylon suture material. On day 79, mild scarring and pigmentation, with almost no vasculature, remained. The menace response and dazzle reflex were normal of OD. Although pigmentation and scarring remained on the cornea, equine AM transplantation can be useful for reconstruction of severe corneal perforation with keratomalacia.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2008.10a
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• pp.174-174
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• 2008

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.439-444
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• 2011

Purpose: To represent the shape of toric corea in the elliptical function for the determination of curvature distribution and lacrimal thickness between cornea and contact lens when the lens is fitted. Methods: Topography measurements of corneal curvature and curvature equation derived from the assumed elliptical function were evaluated using the Excel program which included the necessary equation derived. Results: Mathematical expressions for the cornea whose ribbon shaped-topography image, in which the center does not coincide with the corneal apex, can be determined. Conclusions: For the application where the higher accuracy on the cornea is not required, such as higher order aberration, the cornea cal be expressed in the simple elliptical function.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.473-479
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• 2013

Purpose: This article tried to find the changes of the eye and a correlation depending on watching a smartphone and taking in alcohol. Methods: This paper conducted the refraction inspection, the radius of corneal curvature, tonometry and the corneal thickness measurement and analysis for 31 persons (18 males and 13 females) who have healthy drinking habit, not having the medical history of taking medicine related with disorders of the eye, a mental disease, systemic disease and alcohol metabolism. Results: Of respirations depending on watching a smartphone, the alcohol concentration was significantly decreased in 15 minutes, 30 minutes, 45 minutes, 60 minutes and the convalescent stage. (p<0.01, p<0.001) As the result of comparing the refraction inspection after and before watching a smartphone when drinking alcohol, there was a significant difference in the cylindrical power and the axis. (p=0.005, p=0.001) The change of intraocular pressure depending on watching a smartphone after drinking alcohol was decreased significantly from 30 minutes (p<0.001), and watching a smartphone didn't have any significant effect on the corneal thickness depending on the elapsed time from when drinking alcohol. Conclusions: Watching a smartphone and taking in alcohol had a significant effect on the cylindrical power and the axis. Watching a smartphone and taking in alcohol which may cause the visual function-strain are the factors that need to consider before the refraction inspection.