Topographic Measurements of the Optic Nerve Head with Confocal Scanning Laser Tomography in Normal Koreans

In glaucoma, we need an accurate, highly reproducible analysis method for the purpose of early detection of fine glaucomatous optic nerve head change. Nowadays many investigations using confocal laser tomographic scanner (Heidelberg Retinal Tomograph ; HRT) are actively undertaken. We analyzed the optic nerve head of 479 normal eyes(male:308, female:171) with HRT, and got the mean value of each parameter in HRT. We compared the difference between men and women. We also observed the distribution of the value of each parameter in normal adult. In addition, for the parameter of rim/disc area ratio, we got the mean value in 6 divisions of optic nerve head. The range of distribution of disc area was from 1.139 mm2 to 4.512 mm2, cup area ranged from 0.104 mm2 to 2.667 mm2, and rim area was from 0.760 mm2 to 2.925 mm2. The parameter which showed difference between men and women was height variation contour. For rim/disc area ratio, the mean value of each 6 divisions were as follows: nasal inferior, 0.909; nasal, 0.908; nasal superior, 0.860; temporal inferior, 0.763; temporal 0.519; temporal superior 0.738. We can make good use of the normal parameters of HRT in Koreans for diagnosis and treatment of glaucoma.

The Effect of Diffusion Blur on Central and Peripheral Vision in Normal Adults

Diffusion blur, caused by liquid crystal windows, reduces contrast sensitivity and luminance, so visual acuity is decreased. Moreover, the windows' optical characteristics are similar to those of the cataractous lens. We measured the effect of liquid crystal window on central and peripheral visual acuity using Snellen and grating visual acuity charts. The subjects were 10 normal adults, therefore 20 eyes. We measured the voltage of the liquid crystal window at which the subjects could read the visual acuity chart through the liquid crystal window. In central vision, visual acuity was overestimated according to the Snellen chart, when compared to the results measured by those grating chart. But in peripheral vision, there were no differences between the two visual acuity charts. These results suggested that grating acuity has some limitations when used as a visual acuity test for cataractous patient. The ability of liquid crystal windows to cause diffusion blur suggests they could be used for foUowup observation in treatment of amblyopia or macular diseases.

Topographic Measurements of the Optic Nerve Head with Confocal Scanning Laser Tomography in Normal Subjects and Patients with Glaucoma

We analyzed the optic nerve head of 100 normal eyes with a confocal scanning laser tomograph(Heidelberg Retina Tomograph: HRT), and got the mean value of each parameter in HRT. We also examined 84 eyes of glaucoma patients. Glaucoma patients were divided into 3 groups according to decibel(dB) loss of mean defect on Humphrey visual field test(Central 30-2 program; Group 1:less than 5dB, group 2:between 5dB and 10dB. group 3:greater than 10dB). The mean value of the parameter in HRT are as follows: disk area, 2.35mm2; cup area, 0.48mm2; C/D ratio, 0.20; rim area, 1.86mm2; cup volume, 0.10mm2; rim volume, 0.55mm2; mean cup depth, 0.19mm; maximal cup depth, 0.59mm; cup shape measure, -0.23; height variation contour, 0.42; mean retinal nerve fiber layer thickness, 0.28mm; retinal nerve fiber layer cross sectional area, 1.52mm2. Comparing with normal subjects, group 1 patients had significant difference in cup area, C/D ratio, rim area, cup volume, rim volume, mean cup depth, maximal cup depth, cup shape measure, height variation contour, and mean retinal nerve fiber layer thickness. All glaucoma patients had significantly different value in all parameters. The comparison among each group of glaucoma patients showed significant difference in cup area, C/D ratio, rim area, cup volume, rim volume, cup shape measure, and mean retinal nerve fiber layer thickness.

Topographic Measurements of the Optic Nerve Head with Confocal Scanning Laser Tomography in Normal Subjects and Patients with Glaucoma

We analyzed the optic nerve head of 100 normal eyes with a confocal scanning laser tomograph(Heidelberg Retina Tomograph: HRT), and got the mean value of each parameter in HRT. We also examined 84 eyes of glaucoma patients. Glaucoma patients were divided into 3 groups according to decibel(dB) loss of mean defect on Humphrey visual field test(Central 30-2 program; Group 1:less than 5dB, group 2:between 5dB and 10dB. group 3:greater than 10dB). The mean value of the parameter in HRT are as follows: disk area, 2.35mm2; cup area, 0.48mm2; C/D ratio, 0.20; rim area, 1.86mm2; cup volume, 0.10mm2; rim volume, 0.55mm2; mean cup depth, 0.19mm; maximal cup depth, 0.59mm; cup shape measure, -0.23; height variation contour, 0.42; mean retinal nerve fiber layer thickness, 0.28mm; retinal nerve fiber layer cross sectional area, 1.52mm2. Comparing with normal subjects, group 1 patients had significant difference in cup area, C/D ratio, rim area, cup volume, rim volume, mean cup depth, maximal cup depth, cup shape measure, height variation contour, and mean retinal nerve fiber layer thickness. All glaucoma patients had significantly different value in all parameters. The comparison among each group of glaucoma patients showed significant difference in cup area, C/D ratio, rim area, cup volume, rim volume, cup shape measure, and mean retinal nerve fiber layer thickness.