Optical Consequences of Korean Craniofacial Features

Kwok, L. Stephen,Kim, Douk-Hoon The Korean Ophthalmic Optics Society 2005 한국안광학회지 Vol.10 No.2

This review of the Korean eye anatomy suggests that there may be unsuspected links between anatomical characteristics of the eye and orbit, and optical performance.

Effect of Under and Over Refractive Correction on Visual Acuity Performance using Two Different Charts

Chen, Ai-Hong,Shah, Siti Salwa Mohamad,Rosli, Saiful Azlan The Korean Ophthalmic Optics Society 2013 한국안광학회지 Vol.18 No.3

Purpose: The purpose of this study was to investigate the effect of under and over refractive correction on visual acuity performance and the variation of the visual performance measurement using two different visual acuity charts. Methods: Ten young adults, aged between 19 and 25 years old, were recruited. Inclusion criteria: no history of ocular injury or pathology with a best-corrected visual acuity of 6/6 on dominant eye. The over and under refractive corrections were induced using minus and plus spherical ophthalmic lenses in 0.50 D steps up to 3.00 D; as well as using three axis orientations of cylindrical ophthalmic lenses ($45^{\circ}$, $90^{\circ}$ and $180^{\circ}$) in 0.50 D steps. The variation of visual acuity performance measurements was investigated using Bailey-Lovie LogMAR chart and Landolt C chart. Results: The visual acuity changes with lenses were significantly different between two charts [F = 49.15, p < 0.05 with plus spherical ophthalmic lenses and F = 174.38, p < 0.05 with minus spherical ophthalmic lenses]. The visual acuity changes with three different cylindrical axis showed no significant difference between Bailey-Lovie LogMAR chart [F = 2.35, p > 0.05] and Landolt C chart [F = 3.12, p = 0.05]. Conclusions: The over and under refractive correction affected the visual acuity performance differently. The Landolt C chart and Bailey-Lovie LogMAR chart demonstrated variation in measurements.

Eye Dominance and Reading Speed

Chen, Ai-Hong,Mustapha, Nurfazliha,Rahman, Muhamad Irwan The Korean Ophthalmic Optics Society 2011 한국안광학회지 Vol.16 No.3

Purpose: The aim of this study was to investigate eye dominance and reading performance based on eye movements and reading speed. Methods: The eye dominance of 30 subjects was determined using the sighting test (hole formed by hands). The subjects were asked to read the numerical reading material aloud in English from left to right and from right to left at random. The number of saccades, regressions, and inter-fixations per minute was calculated using Visual-Oculography (VOG) and the reading speed was recorded as number of characters per minute using stopwatch. Results: No significant differences in reading speed among right and left eye dominant subjects as they read from left to right and right to left directions (p>0.05). However, left eye dominant subjects were found to read significantly faster compared to right eye dominant subjects in both directions of reading (p<0.05). In term of eye movement patterns, no significant differences in saccades, regressions, and inter-fixations per minute were found between subjects with right eye dominance and left eye dominance for both reading directions (p>0.05). Conclusions: Reading performance in term of eye movement and speed was not affected by eye dominance, but subjects with left eye dominance read faster than subjects with right eye dominance.

THE CONTACT LENS RELATED CASE REPORTS IN PEDIATRIC POPULATION II

Chen, Ai-Hong,Kim, Douk-Hoon,Sung, A-Young The Korean Ophthalmic Optics Society 2005 한국안광학회지 Vol.10 No.3

The cause of poor visual acuity was connected to the damage by the ocular trauma related. Especially the most cause of visual disorder was identified as irregular pupil by ocular damage. Therefore most patients stopped the wearing of the contact lens immediately by the visual decrease effects from irregular pupil disorder. But we had suggested that the contact lens wear was a very intensive visual therapy. We had identified the visual recover from several tests using the contact lens treatment.

Comparison of Subjective Refraction Findings in Two Different Levels of Room Illumination Using Three Different Types of Letter Charts

Chen, Ai-Hong,Norazman, Fatin Nur Najwa,Buari, Noor Halilah,Ahmad, Azmir,Omar, Wan Elhami Wan The Korean Ophthalmic Optics Society 2010 한국안광학회지 Vol.15 No.1

Purpose: The effect of two different levels of illumination and the effect of three letter chart types on subjective refraction findings were investigated. Methods: This study involved thirty Malay university students aged between 19 to 23 years old (7 males, 23 females), with their spherical refractive error ranged between plano to -7.75D astigmatism ranged from plano to -1.75D, anisometropia less than 1D and with no history of ocular injury and pathology. Monocular subjective refraction was measured under two levels of illumination (with and without room light) and with three different letter charts (Snellen letter chart, wall mounted letter chart and projected letter chart). Subjective refraction finding was calculated in spherical equivalent in unit diopter (D). Results: There was no significant effect in the subjective refraction findings with Snellen letter chart (t-test=0.15, p-value=0.88), projected letter chart (t-test=-0.19, p-value=0.85) as well as wall mounted letter chart (t-test=0.12, p-value=0.94). One Way ANOVA also revealed when the subjective refractive measures were compared under two different level of room illumination (with and without room light), no significant effect of letter chart types on subjective refraction readings with room light ($F_{2.185}$=0.11, p-value=0.89) and without room light ($F_{2.185}$=0.02, p-value=0.98). Conclusions: Subjective refraction findings were not affected whether the room light was on or off. They were also not affected by the types of letter chart used.

Clinical fitting of soft contact lenses

Cho-BOptom, Pauline The Korean Ophthalmic Optics Society 2004 한국안광학회지 Vol.9 No.1

The use of soft contact lenses for myopia correction is increasing in many countries. It is therefore important for contact lens practitioners to be properly educated in fitting these lenses. Before fitting lenses, it is important to consider the factors and procedures related to soft contact lens fitting, indications and contraindications of fitting soft contact lenses. In this article, the functions and activities involved in preliminary, fitting and delivery consultations will be presented.

Calretinin-Immunoreactive Amacrine Cells and Ganglion Cells in the Greater Horseshoe Bat, Rhinolophus ferrumequinum

전영기,전창진,Jeon, Young-Ki,Jeon, Chang-Jin The Korean Ophthalmic Optics Society 2007 한국안광학회지 Vol.12 No.4

Calretinin의 생리적 역할은 아직 확립되지 않았지만, 칼슘 buffer로서의 작용과 칼슘 중재의 신호 변환에 적극적으로 작용하고 있다. Calretinin은 인간의 망막에서 성체 광수용체 세포와 이극세포, 수평세포에서 칼슘의 수송과 칼슘의 생리적 buffering으로서의 역할을 하고 있다. 본 연구에서 한국관 박쥐의 망막의 내핵층과 신경절세포층에서 calretinin의 면역세포화학반응 신경세포들과 그 분포 양상을 조사하여 우리는 박쥐 망막에서 calretinin에 면역세포화학반응을 일으키는 AII 무축삭세포를 내핵층에서 그리고 신경절세포층에서는 신경절세포들을 확인할 수 있었다. 이번의 관찰연구는 우리의 이전 연구와 더불어 박쥐 시력의 풀리지 않는 문제와 박쥐비행의 기동성의 독특한 행동적인 측면들을 더욱 많이 이해하는데 필요하다고 생각한다. Although the physiological roles of calretinin have not been established, it may simply work as a calcium buffer or may actively work in calcium-mediated signal transduction. Calretinin plays a little role in the transport and physiological buffering of calcium in the adult photoreceptor cells, bipolar cells and horizontal cells of the human retina. We identified the calretinin-immunoreactive neurons in the inner nuclear cell layer and ganglion cell layer and the distribution pattern of the labeled neurons in the retina of a bat, Rhinolophus ferrumequinum, in this study. We observed the existence of calretinin-immunoreactive AII amacrine cell in the inner nuclear layer and ganglion cells in the ganglion cell layer of bat retina through this study. This observation must be significant along with our previous studies as we need to study for more understanding about the unsolved issue of a bat vision and the unique behavioral aspects of bat flight maneuverability.

Validating a New Approach to Quantify Posterior Corneal Curvature in Vivo

Yoon, Jeong Ho,Avudainayagam, Kodikullam,Avudainayagam, Chitralekha,Swarbrick, Helen A. The Korean Ophthalmic Optics Society 2012 한국안광학회지 Vol.17 No.2

목적: 본 연구는 각막 전면의 지형과 각막의 두께를 이용하여 각막 후면 정점 곡률과 asphericity(Q)를 측정하기 위해 고안된 새로운 방법의 신뢰도 평가를 위해서 시행 되었다. 방법: 각막 후면의 정점 곡률 및 Q는 Medmont E300 corneal topographer로 측정한 각막 전면의 지형 data와 Holden-Payor optical pachometer로 측정한 각막 수평 경선의 두께 data를 이용하여 계산 되었다. 정확한 각막 두께를 계산 하기위하여 각막 전면 측정 위치의 곡률반경과 각막의 겉보기 두께로부터 각막의 실제 두께를 계산 할 때 정확한 방정식을 이용하였으며, 이는 선행 연구와 구별되는 점이다. 그리고 각막 전면과 후면의 지형은 각막 전면의 지형 data와 계산된 각막 후면의 좌표를 best fit 알고리즘을 이용하여 계산 되었다. 각막 후면의 지형 측정의 신뢰도는 10개의 polymethyl methacrylate(PMMA) lens와 성인 5명의 각막을 측정 하여 평가 하였다. 결과: 10개의 PMMA lens를 이용한 평가에서는 후면 정점 곡률과 후면 Q의 mean absolute accuracy(${\pm}SD$)는 각각 $0.053{\pm}0.044mm$(95% 신뢰구간(CI) -0.033~0.139)와 $0.10{\pm}0.10$(95% CI -0.10~0.31)이였다. 그리고 5명의 각막을 이용한 평가에서의 각막 후면 정점 곡률과 후면 Q의 mean absolute repeatability coefficient(${\pm}SD$)는 각각 $0.07{\pm}0.06mm$(95% CI -0.05~0.19)와 $0.09{\pm}0.07$(95% CI -0.05~0.23) 이였다. 결론: 새로운 방법을 이용하여 신뢰할 수 있는 각막 후면의 지형(정점 곡률과 Q)을 계산 할 수 있었다. 이러한 새로운 방법은 살아있는 인체 각막의 정확한 후면 지형 계산에 적용 될 수 있다. Purpose: Validating a new research method to determine posterior corneal curvature and asphericity(Q) in vivo, based on measurements of anterior corneal topography and corneal thickness. Methods: Anterior corneal topographic data, derived from the Medmont E300 corneal topographer, and total corneal thickness data measured along the horizontal corneal meridian using the Holden-Payor optical pachometer, were used to calculate the anterior and posterior corneal apical radii of curvature and Q. To calculate accurate total corneal thickness the local radius of anterior corneal curvature, and an exact solution for the relationship between real and apparent thickness were taken into consideration. This method differs from previous approach. An elliptical curve for anterior and posterior cornea were calculated by using best fit algorism of the anterior corneal topographic data and derived coordinates of the posterior cornea respectively. For validation of the calculations of the posterior corneal topography, ten polymethyl methacrylate (PMMA) lenses and right eyes of five adult subjects were examined. Results: The mean absolute accuracy (${\pm}$standard deviation(SD)) of calculated posterior apical radius and Q of ten PMMA lenses was $0.053{\pm}0.044mm$ (95% confidence interval (CI) -0.033 to 0.139), and $0.10{\pm}0.10$ (95% CI -0.10 to 0.31) respectively. The mean absolute repeatability coefficient (${\pm}SD$) of the calculated posterior apical radius and Q of five human eyes was $0.07{\pm}0.06mm$ (95% CI -0.05 to 0.19) and $0.09{\pm}0.07$ (95% CI -0.05 to 0.23), respectively. Conclusions: The result shows that acceptable accuracy in calculations of posterior apical radius and Q was achieved. This new method shows promise for application to the living human cornea.