The Change of Corneal Endothelial Permeability and Corneal Thickness after Topical Steroid Treatment

Changes of corneal endothelial permeability and corneal thickness after instillation of topical steroid was evaluated. In five rabbits, 0.1%dexamethasone eye solution was dropped into right eyes, and in another five rabbits, 1%prednisolone acetate eye solution was dropped into right eyes, and each left eyes were used as a control with dropping of Tears Naturale(r)II (Alcon-couvreur, Belgium). After dropping eyedrops for seven days, corneal endothelial permeability and corneal thickness were measured. Mean corneal thickness changed from 371.4 micrometer to 334.2 micrometer after dropping eyedrops in 0.1%dexamethasone group, and from 375.8 micrometer to 347.8 micrometer in control group where no statistical difference was noted between the two groups. Corneal endothelial permeability was 3.58x10(-4)cm/min in 0.1%dexamethasone group, and 3.54x10(-4) cm/min in control group(p>0.05). Mean corneal thickness changed from 347.4 micrometer to 323.8 micrometer after dropping eyedrops in 1% prednisolone acetate group, and from 342.4 micrometer to 335.6 micrometer in control group. There was also no statistical difference between the two groups. Corneal endothelial permeability was 4.08x10(-4)cm/min in 1%prednisolone acetate group, and 4.26x10(-4) cm/min in control group(p>0.05). In conclusion, topical application of 0.1%dexamethasone or 1%prednisolone acetate for a short period may have no effect on corneal endothelial permeability and thickness.

Comparison of Various Kinds of Stereoacuity Tests in Preschool Children

The criteria for a good stereoacuity test in preschool children should be easy and provide accurate measurement of stereoacuity.To determine the success rate and efficacy of stereoacuity tests, and percentage of children between age of 2 and 3 years who correctly identified shapes and symbols of each stereoacuity test, we administered the Lang, Titmus circle, Titmus, animal, Randot circle, Randot shape and Randot preschool stereoacuity test in 96 patients whose ages ranged between 2 to 5 years. The overall success rates of the Lang, Titmus circle Titmus animal, Randot circle, Randot shape and Randot preschool stereoacuity tests were 84.4%, 72.9%, 75%, 75%, 75%and 84.4%, respectively.The overall success rates of the Lang and Randot preschool stereoacuity test tended to be higher among the methods.The sensitivity of the Lang and Randot preschool stereoacuity test was 100%and best among all methods.The percentage of 2-to 3-year-olds who correctly identified the shape of star, cat, car, elephant, rabbit, hand, truck, house, tree and round was higher than that of other shapes. The shapes of squirrel, monkey, heart, E, and cross was lower than that of other shapes.The Lang or Randot preschool stereoacuity test which uses shapes and symbols readily recognizable by children was found to be easy and accurate stereotests for preschool children, especially in uncooperative 2-to 3-year-olds.

The Effect of Mitomycin-C on the Function of Corneal Endothelial Cells in Rabbit

The purpose of this study is to investigate the toxicity of mitomycin-C[MMC]to the corneal endothelial cells, which is medical adjunct to pterygium and glaucoma surgery.Rabbit corneas were mounted in the in-vitro dual-chambered specular microscope.Corneal endothelium was perfused with the glutathione-bicarbonate-Ringer[GBR]solution for one hour, then, perfused with 0.02%, 0.01%, and 0.005%MMC in GBR solution in experimental groups, and with GBR solution only in control group.Corneal thickness was measured every 15 minutes during perfusion and corneal swelling rate was calculated.Corneal endothelial permeability was also measured in another experiment.In MMC-mixed group, the early swelling rate decreased due to osmolarity of MMC, but after removal of MMC, the swelling rate increased compared to that of the control group.The pattern of increase was not a linear form, but a secondary curve with the plateau. In 0.02%and 0.01%MMC group, corneas swelled significantly, but not in 0.005%group.Corneal endothelial permeability was 4.21 +/-0.50 x10-4cm/min at 0.005%MMC, 4.10 +/-0.93 x10-4cm/min in control, and 4.25 +/-0.48 x10-4cm/min at 0.01% MMC, 3.73 +/-0.73 x10-4cm/min in control. No significant changes in permeability was observed.In conclusion, MMC of 0.01% or higher exposed to corneal endothelial cells induced corneal swelling of which mechanism was thought to be due to inhibition of Na/K-ATPase by MMC.

The Effect of Reablation on the Undercorrected Eye after LASIK

We evaluated the effect of the reablation on the undercorrected eye after the Laser in-situ keratomileusis [LASIK]. The subjects were 21 eyes of 19 patients, who showed undercorrection after the LASIK. Reablation was done on the stromal bed after lifting the original flap aside. Patients were followed up for 1 to 6 months after the reablation. At the time of first LASIK, the mean spherical equivalent[S/E]was -11.29 +/-2.98D preoperatively, -1.90 +/-1.16D at postopera-tive 3 months, the mean amount of correction was -9.60 +/-1.90D. At the time of reablation, the mean[S/E]was -3.26 +/-1.08D, and the mean amount of correction was -3.31 +/-1.11D. Reablation was done only after the refractive error stabilized and did not change over 3 months. One month after the reablation, the mean[S/E]was +0.15 +/-0.98D and 85.7%of the eyes were within +/-1.0D. Six months after the reablation, the mean[S/E]was -0 .1 0 +/-0.66D and 84.6% were within +/-1.0D. The uncorrected visual acuity of 0.6 or more was achieved in 76.2%of eyes at 1 month, and 84.6%at 6 months. The best spectacle-corrected visual acuity [BSCVA]was lost 2 lines or more in 14.3%at 1 month, but none at 6 months after surgery. The BSCVA did not change or gain 1 line or more in 76.2%at 1 month, and 92.3%at 6 months after surgery. There was no problem when lifting the original corneal flap. In conclusion, reablation using the original flaps without new cuts seems to be a redictable, safe method for retreatment.

Assessment of Stereoacuity with the Randot Preschool Stereoacuity and Lang Test in the 2-to 5-Year Age Range

The evaluation of stereoacuity provides relatively accurate assessment of binocular function. However, it is difficult to perform and also the reliability rate is low in the 2-to 5-year-old age range. We investigated the over-all success rate, the success rate according to age, and efficacy with the Randot preschool stereoacuity and Lang test in the 2-to 5-year-old children of 96 patients. The overall success rate of the two stereotests were 84. 4%, 47. 4%in the 2-year-old children and more than 87%in children over 3-year-old. When children with normal binocular vision were examined with the Randot preschool stereoacuity test, mean stereoacuity was 333 arc sec in the 2-year-age group, 135 arc sec in the 3-year-age group, 48 arc sec in the 4-year-age group, and 50 arc sec in the 5-year-age group. Sensitivity and specificity of Randot preschool stereoacuity test were 100%, 94. 2%, respectively. Sensitivity and specificity of Lang test were 100%, and 92. 4% respectively. As a result, Randot preschool stereoacuity and Lang stereotests might be considered easy available and valuable test for evaluating binocular function in the 3-to 5-year-old preschool children. Moreover, the Randot preschool stereoacuity provided a relatively accurate measurement of stereoacuity in the 3-to 5-year-old age range.