• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.4
• /
• pp.339-345
• /
• 2005

In this paper, we studied the principle that correct the emmetropia to the aphakia using intraocular lens. At present, in an ophthalmic clinic, I.O.L which is using for correction of the vision clinically has presented how to prescribe more accurately by using optical method. To correct the Aphakia for the emmetropia, we considered that the basic cause of Ametropia was the refraction and the axial length. The correction principle is made equal to the Back Focal Length(BFL) and the vitreous length from lens to retina. For the confirmation of the correction principle, we used the Gullstrand number I eye model in emmetropia. For the myopia and hyperopia, we used the clinical data and replaced crystalline lens with intraocular lens.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.3
• /
• pp.347-356
• /
• 2013

Purpose: To evaluate the visual acuity and visual performance after implantation of a aspheric multifocal (ReSTOR$^{(R)}$ SN6AD3) intraocular lens (IOL). Methods: Nineteen cataract patients (30 eyes) implanted with an aspheric multifocal IOL (ReSTOR$^{(R)}$ SN6AD3) either unilaterally or bilaterally were participated. Visual acuity (VA) and objective optical performance were evaluated at the time of preoperation, 1 week, 1 month, and 3 month after operation. At 3 month of post-operation, objective visual performance were measured and compared with the 38 eyes of 20 age-matched normal control. Distance VA was measured by using the ETDRS LCD chart and intermediate and near visual acuity were measured using Jaeger chart. Objective visual performance was assessed preoperatively and 1 week, 1 month and 3 month postoperatively using a double-pass system (Optical Quality Analysis System) with a 4-mm pupil diameter, the OSI (objective scatter index), MTF (modulation transfer function) cut off and strehl ratio. At 3 month of post-operation, visual acuity and visual performance compared with age matched normal control. Results: The uncorrected distance VA, OSI, MTF cut off and strehl ratio were significantly improved (p<0.05) until 1 month postoperatively. Visual performance of MTF cut off and strehl ratio after 3 month of operation were significantly improved compared to the normal control (p=0.063, p=0.103 respectively), however, OSI was higher than normal control. Patients implanted with aspheric multifocal IOL were satisfied with distance and near VA however, were unsatisfied with intermediate VA and reported glare and halos. Conclusions: The visual performance reaches to a stable condition in 1 month of implantation of aspheric multifocal IOL and improved to the level of age-mated normal patients. Also patients were satisfied with their quality of vision, however, intermediate VA, glare and halos were reported as complications.

• Korean Journal of Optics and Photonics
• /
• v.25 no.1
• /
• pp.21-28
• /
• 2014

In this paper a Super Multi-view display method using a pinhole array with full parallax was proposed. The proposed method was simulated and its parameters analyzed. Also, the distribution and irradiance of light through each pinhole on the retina receiver, according to the change of crystalline lens focal length, were found by simulation. As a result, an image free of blurring was obtained while the crystalline lens focused on the depth plane of the three-dimensional image created by the imaging lens.

• Journal of Korea Multimedia Society
• /
• v.12 no.4
• /
• pp.502-511
• /
• 2009

In order to simulate a depth-of-field effect in real world, there have been several researches in computer graphics field. It can represent an out-of-focused scene by calculating focal plane. When a point in a 3D coordinate lies on further or nearer than focal plane, the point is presented as a blurred circle on image plane according to the characteristic of the aperture and the lens. We can generate a realistic image by simulating the effect because it provides an out-of-focused scene like human eye dose. In this paper, we propose a method to calculate a disparity value of a viewer using a customized stereoscopic eye-tracking system and a GPU-based depth-of-field control method. They enable us to generate more realistic images reducing side effects such as dizziness. Since stereoscopic imaging system compels the users to fix their focal position, they usually feel discomfort during watching the stereoscopic images. The proposed method can reduce the side effect of stereoscopic display system and generate more immersive images.

• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.2
• /
• pp.145-149
• /
• 2005

In a artificial hypermetropia with the accommodative response, we investigated a diameter of blur circle as a function of test lens refractive power. In a schematic eye model of the hypermetropia, the second focal length along to accommodated power of the crystal lens are calculated as a function of test lens power and, also distance between the retina and exit pupil are calculated as a function of accommodated power. As these results are compared, the size of blur circle on the retina are obtained.

• Cartoon and Animation Studies
• /
• s.49
• /
• pp.383-398
• /
• 2017

Virtual Reality contents are being used as media in various fields. In order for the virtual reality contents to be realistic, the scale of the objects in the virtual reality must be the same as the actual size, and the user must feel the same size. However, even if the size of the character in the virtual reality space is made equal to the size in comparison with the size of the character in the reality, the distortion of the size can occur when the user looks at the object in the image with the HMD. In this paper, I investigate the requirements related to size in virtual reality, and try to find out what difference these requirements have in virtual reality and how the difference affects users. Experiments and surveys to compare the size of objects in virtual reality space and the size of objects in real space were conducted to investigate how scale distortion occurs at distant and near places. I hope that this paper will be a useful research for virtual reality developers.