The purpose of this report is to investigate experimentally how the corea, sclera, crystalline lens and focusing lens influence the ultrasound intensity and beam width and to find characteristic differences due to the transducer parameters; frequency and size. A time-amplitude ultrasonic diagnostic apparatus, Aloka Model SSD-2D was used with transcucers of 10 MHz and 5 MHz, 10 mm and 5 mm diameters. The metal ball, 1 mm in diameter, was served as the echo-reflecting target which was immersed in water and moved horizontally under the transducer with a micrometer screw. The distances between the transducer and the metal ball varied from 10 mm to 50 mm in 10 mm step. The amplitudes curves of the echoes so obtained were represented by relative values. In water control experiment, the nearer the metal ball from the transducer, the more irregular the curves, with multiple amplitudes maxima and minima. These irregular curves became homogeneous as the transducer moved away from the target. The multiple peak curves were more marked when measured with transducers of higher frequency and larger diameter. At the end of the near field only a single peak was found in the axial portion of the sound field. In the far field, the beam width reduced slightly due to the divergence of the beam accompanied by slight attenuation of the echo amplitudes. When the sound beam passed through the cornea and sclera, the form of the curves remained almost unchanged, but the amplitudes decreased slightly due to the absorption of the sound energy. Scleral tissue absorbed the energy more strongly then the corneal tissue. When the crystalline lens was placed under the transducer, divergence of the beam and themoderate absorption took place. This effect was more pronounced with the use of transducers of higher frequency and smaller diameter. When a focusing lens, 25 mm focal length, was attached to the transducer surface, sound beam converged to a narrow zone, followed by later scattering. These results suggest that the transducer should be selected as to the frequency and diameter according to the site of the lesion suspected and the nature of the pathology.
Absorption ; Cornea ; Lens, Crystalline ; Pathology ; Sclera ; Transducers ; Ultrasonics* ; Ultrasonography ; Water

The pattern and morphology of cellular infiltration of iris melanocytes implanted into the corneal stroma were studied with a rabbit corneal model. Iris melanocytes are transformed into fibroblast-like cells with a loss of pigment granules, which may reflect the in vivo characteristics of iris melanocytes under pathologic conditions. The metaplastic chararter of iris melanocytes appears to be related to the formation of retrocorneal pigmentation and fibrous membrane.
Animals ; Cell Division ; Cornea/*cytology/pathology/surgery ; Iris/*cytology ; Melanocytes/*cytology/physiology/transplantation ; Metaplasia/pathology ; Rabbits

Rigid contact lenses with eccentricity through manufacture can more or less influence visual correction or induce the corneal warpage. Therefore the fine detection of rigid contact lens eccentricity is needed and important. This study was aimed to design a system for lens eccentricity measurement by the principle of optical reflection. By using a standard concave mirror in the center of lens jig, the geometrical center of a lens could be detected accurately. It has solved the problem of lens distortion and breakableness attributed to the conventional method based on rotating reflection. The system is proved to be of practical method with good repeatability.
Contact Lenses ; adverse effects ; Cornea ; pathology ; Refraction, Ocular ; physiology ; Refractive Errors ; pathology

The aim of this study was to assess the involvement of multipotential progenitor cells in the pathogenesis of Mooren's ulcer using immunohistochemical staining techniques. Tissue specimens were collected from 3 Mooren's ulcer patients who underwent lamellar keratectomy. Immunohistochemical staining patterns were analyzed using antibodies: CD34, c-kit, STRO-1, CD45RO, VEGF and alpha-SMA. Strong positive CD34, c-kit and STRO-1 cells were revealed in Mooren's ulcer specimens, especially in the superficial stroma. A few weakly expressed CD34 stroma cells were seen in normal limbal cornea but no immunoreactivity for c-kit and STRO-1 could be found. CD45RO positive T cells were found to have infiltrated in Mooren's ulcer. The immunostaining pattern of VEGF and yen a- SMA was closely correlated with the degree of expression and the number of CD34 positive cells. Bone marrow-derived multipotential progenitor cells may be involved in the pathogenesis of Mooren's ulcer by synergizing with other factors to amplify autoimmune destructive reactions and to contribute to the regeneration process. Specific therapeutic strategies that target the role of these cells in the disease are warranted.
Cornea/*pathology ; Corneal Ulcer/*pathology ; Hematopoietic Stem Cells/*pathology ; Humans ; Multipotent Stem Cells/*pathology ; Research Support, Non-U.S. Gov't

OBJECTIVETo evaluate the impact of hyphema secondary to high intraocular pressure on corneal pathology in rabbits.

METHODSThirty adult New Zealand rabbit were randomized into 3 equal groups, and in each rabbit, one eye served as the experimental eye with the other as the control eye. In the experimental eye, autoblood was injected into the anterior chamber to induce high intraocular pressure maintained for 3, 5, or 8 days. Only saline was injected into the control eye. After the injections, the cornea was observed with slit-lamp microscopy, and at 3, 5, or 8 days, the experimental and control eyes were taken from the 3 groups for microscopic examination of the corneas to detect the occurrence of cornea bloodstain with prolonged high intraocular pressure. Corneal edema, elastic fibers changes, growth of new blood vessels, changes of eosinophils, fibroblasts, lymphocytes and plasma cells, as well as the pathological changes of the corneal layers were observed and compared between the experimental and control eyes.

RESULTSMaintenance of high intraocular pressure for 8 days resulted in the most severe corneal edema and thickening, and histopathologically, the corneal stroma showed widened space between the elastic fibers and obvious fiber distortion. Neovascularization was seen in the marginal cornea where eosinophil infiltration occurred with a small number of lymphocytes, plasma cells and fiber cells. All the three groups showed more obvious edema in the posterior than in the anterior cornea.

CONCLUSIONProlonged hyphema with ocular hypertension results in aggravation of corneal edema, and corneal blood staining does not occur until 8 days of high intraocular pressure but corneal elastic fiber disruption can be seen, suggesting the impending irreversible pathological changes of cornea.

Animals ; Cornea ; pathology ; Edema ; pathology ; Female ; Hyphema ; complications ; pathology ; Male ; Ocular Hypertension ; complications ; pathology ; Rabbits ; Random Allocation

We report the clinical features and the course of traumatic corneal endothelial rings by trauma. Fourteen eyes (of fourteen patients) with traumatic endothelial rings (twelve cases of BB shot injury), were enrolled in this study. With median follow-up interval of 50 weeks, initial and final best corrected visual acuity, presence of combined injuries such as gross hyphema, and time of disappearance of traumatic endothelial rings were recorded. And specular microscopic examination was performed. The duration of existence of traumatic endothelial rings was mean 4.6 days. On the specular microscopic examination, the count of corneal endothelial cells in the injured eye decreased by mean 16.8% (ranged from 1 to 56%) than that in the opposite unjnjured eye. The duration of existence of traumatic endothelial rings was 3.5 days in the group without combined angle recession and was 6.1 days in the group with combined angle recession. We suggest that the possibility of traumatic corneal endothelial rings and resultant endothelial cell loss and their clinical potential should be always kept in mind in ocular trauma, particularly BB shot injury.
Adolescent ; Adult ; Aged ; Child ; Cornea/*injuries ; Endothelium, Corneal/*pathology ; Eye Injuries/*pathology ; Human ; Male ; Retrospective Studies ; Wounds, Gunshot/pathology

PURPOSE: To use impression cytology to examine the structural changes in corneal epithelial cells infected with the herpes simplex virus in rabbit eyes. METHODS: Corneal surfaces of 7 rabbits were scratched using a 25-gauge needle. Herpes simplex virus (type 1, Kos strain) was inoculated to the injured cornea. As the corneal diseases were observed using slit lamp biomicroscopy, impression cytology was performed for 18 days after inoculation. Specimens were stained with hematoxylin-eosin and examined using optical microscopy. RESULTS: Corneal lesions consisted mainly of round epithelial cells, inflammatory cells, ballooning cells, multinucleated giant cells, and various inclusion bodies. Over time, the corneal epithelial cells peeled away as a result of corneal edema in the corneal lesions. Dendritic lesions were also observed. In the recovery phase, the number of detached cells and infiltrated inflammatory cells decreased. CONCLUSIONS: It was presumed that dendritic lesions might have been formed at the scratched cornea region, thereby aggravating the epithelial cells falling off as a result of the infiltration of inflammatory cells. These cytopathologic effects occur in experimental herpes simplex keratitis.
Animals ; Cercopithecus aethiops ; Cornea/*pathology ; Cytological Techniques ; Epithelium, Corneal/pathology ; Keratitis, Herpetic/*pathology ; Rabbits ; Time Factors ; Vero Cells

A tectonic keratoplasty was performed with a keratoprosthesis using expanded polytetrafluoroethylene as a supporting skirt, on the left eye of a 23-year-old woman who needed an emergency corneal transplantation due to corneal perforation. The keratoprosthesis implanted, consisted of a supporting skirt which was made of expanded polytetrafluoroethylene (PTFE), and an optic portion which was made of polymethylmethacrylate (PMMA). The optic portion and the supporting skirt were attached by cyanoacrylate tissue adhesive (Histoacryl(R)). Two months post-operatively, the keratoprosthesis was extruded, leaving an opacified, vascularized cornea. A penetrating keratoplasty was performed 1 month later. The excised cornea was composed of granulation tissue. To our knowledge, this is the first case of tectonic keratoprosthesis using expanded PTFE as a supporting skirt in humans.
Adult ; Cornea/pathology/*surgery ; Corneal Opacity/pathology ; Female ; Granuloma/pathology ; Humans ; *Keratoplasty, Penetrating ; *Polytetrafluoroethylene ; *Prostheses and Implants ; Reoperation

The most important problem in the transplantation of artificial cornea is the extrusion of keratoprosthesis. So we performed this study to know the conditions to keep the keratoprosthesis as long as possible after animal experiment with experimental keratoprosthesis of various material and structure. We concluded from the results that silicone barrier could not prevent the retroprosthetic membrane, and fluorosilicone was not adequate material as an optic. And the following conditions are required to maintain keratoprosthesis as long as possible; optic made of PMMA, retention plate made of PTFE with 0.6 mm thick, anterior direction of optic, large optic, intralamellar suture technique. Furthermore we postulated that enzymatic theory is more appropriate than aseptic necrosis theory about the extrusion of keratoprosthesis.
Animals ; *Cornea/pathology ; Corneal Transplantation ; Methylmethacrylate ; *Methylmethacrylates ; *Polytetrafluoroethylene ; *Prostheses and Implants ; Prosthesis Design ; Rabbits

Under the postulation that the double Ruiz procedure could increase the effect of radial keratotomy (RK), RK combined with horizontal and vertical Ruiz procedure was performed in three groups of 22 rabbit eyes. In the group A of six eyes, RK with vertical Ruiz procedure was performed, and eight weeks later horizontal Ruiz procedure was added. In the group B of eight eyes, RK with horizontal Ruiz procedure was performed, and four weeks later vertical Ruiz procedure was added. In the group C of eight eyes, RK with horizontal and vertical Ruiz procedure was performed simultaneously. As a control, in the group D of eight eyes, RK without Ruiz procedure performed. Changes in keratometry for four weeks and eight weeks postoperatively were analyzed. The results were as follows: 1. At eight weeks postoperatively, mean changes in keratometry were 6.434D, 3.663D, 4.030D and 1.585D in groups A, B, C and D, respectively. 2. Mean changes in keratometry of groups A, B and C were significantly higher than that of group D. 3. Mean changes in keratometry of 6.434D in group A was significantly the highest of the three groups in which double Ruiz procedure was performed. For the above results, it was concluded that double Ruiz procedure increased the effect of RK, and the procedure was more effective when the secondary Ruiz procedure was added eight weeks later.
Animals ; Astigmatism ; Cornea/*pathology/physiopathology ; Keratotomy, Radial/adverse effects/*methods ; Rabbits ; Time Factors