To investigate if excimer laser ablation of the corneal stroma affect the Barrier function of the corneal endothelial cells and to establish the depth Of excimer laser ablation that will not impair endothelial barrier.
Corneal Stroma ; Endothelial Cells ; Lasers, Excimer* ; Permeability*

In order to compare the clinical results of Automated Lamellar Keratoplasty with Laser Assisted In Situ Keratomileusis for corection of high myopia, the effects of the procedure on 9 patients(10eyes) following ALK and 14 patients(15 eyes) following LASIK who were followed up at least 6 months were analyzed retrospectively. Mean preoperative spherical equivalent(S.E) was -17.32D(-11.50D~-22.50D) in ALK group and -16.05D(-12.00D~-24.00D) in LASIK group, while mean postoperative S.E was -3.19D at 1 week, -3.50D at 1 month, -4.12D at 3 months, -3.83D at 6 months in ALK group and +2.10D at 1 week, 0.70D at 1 months, -0.10D at 3 months, -0.58D at 6 months in LASIK group. Mean preoperative uncorrected visual acuity was 0.03 in ALK group and 0.04 in LASIK group. At postoperative 6 months, mean uncorrected visual acuity was improved to 0.18 in ALK group and 0.52 in LASIK group. The percentages of patients achieving correction within +/-1.00D at 6 months were 20% in ALK group and 47% in LASIK group. Postoperative cylindrical change was not significant in each group(p>0.05) and also best corrected visual acuity did not show statiscally significant changes in each group(p>0.05). The complications included folds of corneal flap, increased IOP, night halo, and corneal haze. In conclusion, ALK, when performed for high myopia with Ruiz normogram, resulted in undercorrection. LASIK seems to be much more predictable and accurate than ALK in high myopia.
Corneal Transplantation* ; Humans ; Keratomileusis, Laser In Situ ; Myopia* ; Retrospective Studies ; Visual Acuity

The concentrations of fibronectin in aqueous humor, measured by ELISA which was developed to detect fibronectin, ranged from 5 ng/ml to 100 ng/ml. Aqueous humor was aspirated from human eyes with cataracts and glaucomas using a 26 gauge needle through the peripheral cornea before making the limbal incision into the anterior chamber during surgery. The results of the study show that the average concentration and standard deviation of fibronectin was 0.136 +/- 0.192 microgram/ml in cataract eyes, and 0.962 +/- 0.918 microgram/ml in glaucoma eyes respectively. There was a statistically significant difference between both groups (p = 0.000). However, no significant differences according to age and sex were noted. There was no influence due to preoperative intravenous mannitol injection on fibronectin concentration. The source of aqueous fibronectin is still not clearly known and the mechanism of the higher concentration of fibronectin in glaucoma has not been clearly disclosed, however it is thought that normally present fibronectin is accumulated in the anterior chamber because it can not pass the aqueous outflow pathway, or that fibronectin production may be increased in glaucoma.
Adolescent ; Adult ; Aged ; Aqueous Humor/*metabolism ; Cataract/metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Fibronectins/*analysis ; Glaucoma/metabolism ; Humans ; Male ; Middle Aged

Topical fibronectin, autologous and homologous, was used to treat nine patients (eleven eyes) with persistent corneal epithelial defects and corneal ulcers that failed to improve with standard therapy. The fibronectin was purified from autologous and homologous plasma by gelatin-Sepharose 4B affinity chromatography and administered topically, 500 micrograms/ml five times a day, for three weeks. Complete or nearly complete reepithelialization was achieved in all patients regardless of the source of fibronectin, autologous or homologous. But healing times varied. The average healing time was 41.7 +/- 14.7 days (35.7 +/- 12.4 days for autologous, 50.8 +/-14.4 days for homologous). Ocular symptoms were relieved significantly, and no side effects were observed. Over an average follow-up period of 5.2 months, no recurrences were noted. The results showed that homologous, as well as autologous, fibronectin was effective in patients with persistent corneal epithelial defects and corneal ulcers.
Administration, Topical ; Adult ; Aged ; Blood Proteins/isolation & purification ; Chromatography, Affinity ; Corneal Diseases/*drug therapy ; Corneal Ulcer/*drug therapy ; Epithelium/drug effects ; Female ; Fibronectins/administration & dosage/isolation & purification/*therapeutic use ; Humans ; Male ; Middle Aged ; Visual Acuity ; Wound Healing/drug effects

Morphometric variables of the corneal endothelial cells and central corneal thickness were evaluated in 12 neovascular glaucoma eyes and 12 normal contralateral eyes. Cell area and density was 611.50 micrometer2, 2,065 cells/mm2 respectively in neovasualar glauloma eyes and 441.33 micrometer2, 2,313cells/mm2 respectively in normal contralateral eyes and there were no significant diffeernce between two groups (p>O.1). Hexagonality was 55.69% in neovascular glaucoma eyes and 62.01 % in normal contralateral eyes and the decrease in hexagonality in the former was statistically significant (P0.05). It can be concluded that neovascular glaucoma induces morphological changes of the corneal endothelial cens which might bring corneal edema.
Corneal Edema ; Endothelial Cells* ; Glaucoma, Neovascular*

Morphometric variables of the corneal endothelial cells and central corneal thickness were evaluated in 12 neovascular glaucoma eyes and 12 normal contralateral eyes. Cell area and density was 611.50 micrometer2, 2,065 cells/mm2 respectively in neovasualar glauloma eyes and 441.33 micrometer2, 2,313cells/mm2 respectively in normal contralateral eyes and there were no significant diffeernce between two groups (p>O.1). Hexagonality was 55.69% in neovascular glaucoma eyes and 62.01 % in normal contralateral eyes and the decrease in hexagonality in the former was statistically significant (P0.05). It can be concluded that neovascular glaucoma induces morphological changes of the corneal endothelial cens which might bring corneal edema.
Corneal Edema ; Endothelial Cells* ; Glaucoma, Neovascular*

To investigate the effect of deep excimer laser ablation on the corneal endothelium, excimer laser photo refractive keratectomy(PRK) with different ablation depths were performed to obtain various residual corneal thickness(range: 90-250 micrometer) in white rabbit corneas(N=50). Corneal endothelium was stained with Alizarin red S(pH 4.2) for 2 minutes three days after excimer laser ablation and was analyzed morphometrically using digitizer the morphometric parameters according to residual corneal thickness. In the corneas of residual corneal thickness(RT) over 200 micrometer and untreated controls(N=6), endothelial damages were rarely seen. With the decrease of residual corneal thickness, hexagonality and shape factor decreased, and coefficient of variation of the cell area(CV) increased(p<0.01). In corneas of RT less than 200 micrometer, endothelial damages were found and become more severe in corneas of RT between 90~149 micrometer. Hexagonal shaped cells were rarely observed, and the shapes of most cells were changed. Deep excimer laser PRK might affect corneal endothelial cells if the RT is less than 200 micrometer, and these findings suggest that care is recommended when doing deep excimer laser corneal ablation, especially excimer laser assisted in situ keratomileusis.
Cornea ; Endothelial Cells ; Endothelium, Corneal ; Lasers, Excimer*

In present, clinically, the VEP has special value in the areas of refraction, infant acuity, diseases of the optic nerve, color blindness, amblyopia and field defects. VEP reflects the the activity of the visual system from the level of the photoreceptors to the occipital cortex, and it is more directly related to vision than retinoscopy. Authors studied the YEP change in refractive errors. We used Horizon computer with UTAS-E and the check sizes used were 16 X 16(50 min.), 32 X 32(25 min.), 64 X 64(12.5 min). One eye was occluded and then lenses of different power were successively placed before the other eye, and a seperate VEP was recorded for each lens power. The result were as follows: 1. Amplitude change according to change of check size in different trial lens powers. 1) +3, +4, +5D (64 X 64): statistically significant decrease. 2) -D(except -6D, 32 X 32): statistically not significant. 2. Latency change according to change of check size in different trial lens powers. 1) +D(64 X 64 and +4, +5D(32 X 32): statistically significant increase. 2) -D(64 X 64) and -10D(32 X 32): statistically significant increase. 3. Amplitude change according to change of trial lens power in different check sizes. 1) All check size(+4, +5D) and 64 X 64 size(+3D): statistically significant decrease. 2) All check size(-D): statistically significant decrease. 4. Latency change according to change of trial lens power in different check sizes. 1) 32 X 32 size(+4, +5D) and 64 X 64size(+3, +4, +5D): statistically significant increase. 2) 16 X 16 size(-6, -8, -10D) 32X32 size(-4, -6. -8, -10D) and 64X64 size (all D): statistically significant increase. 5. Change of amplitude and latency between each trial lens power in different check sizes. 1) +D(64 X 64), amplitude and Latency: statistically significant. 2) -D amplitude-all check size: statistically significant, latoncy-32 X 32 size: statistically significant.
Amblyopia ; Color Vision Defects ; Humans ; Infant ; Optic Nerve ; Refractive Errors* ; Retinoscopy

The stability, efficacy, predictability, and safety of LASIK with 5.0 mm zone ablation was assessed and the relation between the amount of correction and the amount of ablation was also evaluated to determine how much we need to ablate the corneal stroma. In this study, we present our data on the 125 cases of myopic correction by LASIK, using ExciMed UV 200LA[Summit Technologies Inc. USA]. The patients were divided into 4 groups with preoperative myopia. About 90% of myopic error at the corneal plane was ablated and uncorrected visual acuity[UCVA], best corrected visual acuity[BCVA], intraocular pressure[IOP], and manifest refraction[MR] were checked 1 week, 1 month, 3 months, 6 months, 9 months, and 1 year after LASIK. Spherical refraction improved from -11.94D preop to -0.53D postop one year. 57.1% of eyes was within+/-0.50D and 85.7% was within+/-1.0D of emmetropia one year after LASIK. UCVA of 0.5 or better was achieved in 74.3% of eyes that is because preoperative BCVA was below 0.5 in many cases. BCVA was improved or unchanged, in 90.0% of the eyes one year after LASIK. In eyes with -20.0D of preoperative spherical value or less, ablation of about 90% of spherical value at the corneal plane made 102.9% of attempted correction 9 months after LASIK and 98.3% of attempted correction 1 year after LASIK. In eyes over -20.0D, 89.8% of attempted correction was achieved 9 months after LASIK. In conclusion, this study suggest that the ablation of 90% of preoperative myopic error at the corneal plane is reasonable for LASIK using 5.0 mmablation zone.
Corneal Stroma ; Emmetropia ; Humans ; Keratomileusis, Laser In Situ* ; Myopia ; Nomograms

No Abstract Available.
Animals ; Cats* ; Endothelium, Corneal*