PURPOSE: To describe the morphological features of a prominent ectasia of the cornea after laser in situ keratomileusis (LASIK). METHODS: The morphology of the ectatic corneas were examined using corneal topography, optical microscopy and transmission electron microcopy in 2 cases who had undergone penetrating keratoplasty due to a poor visual acuity induced by progressive corneal ectasia after LASIK. RESULTS: On a topographic examination, the apex of the corneal surface was observed within the central 3 mm zone and the smallest thickness was 116 micrometer and 271 micrometer in each case. The histological examination showed that the epithelial layer had become thinner and detached easily. The Bowman's membrane was broken down and folded. An irregular arrangement of the stromal lamellae with the fibroblastic keratocytes was found. Scar tissue was observed between the epithelium and the Bowman's layer in the central region. In contrast, the corneal endothelium was intact and no abnormality was found in both cases. CONCLUSIONS: The morphologic examination of 2 cases with corneal ectasia revealed a forward protrusion of both the anterior and posterior corneal surface. In addition epithelial detachment, breakage and folding of the Bowman's membrane and irregular lamellae were found. The 2 cases had greatly thinned and protruding corneas, yet there was no abnormality in the corneal endothelium.
Bowman Membrane ; Cicatrix ; Cornea ; Corneal Topography ; Dilatation, Pathologic ; Endothelium, Corneal ; Epithelium ; Fibroblasts ; Keratoconus ; Keratomileusis, Laser In Situ* ; Keratoplasty, Penetrating ; Microscopy ; Visual Acuity

PURPOSE: To evaluate the clinical outcome of multilayer amniotic membrane transplantation (AMT) in the cornea which was perforated or had impending perforation due to corneal ulcer. METHODS: Human multilayer amniotic membrane transplantation were performed in patients with perforation or impending perforation of cornea due to herpetic keratopathy (2 eyes of 2 patients) and fungal ulcer (1 eye). The surgical procedure consists of the following steps: First, all cellular debris was carefully removed from the base and the walls of the ulcer and loosened epithelium. In addition 1 to 2 mm zone is created around the ulcer by removal of healthy, adherent epithelium overlaying the normal Bowman membrane. Depending on the depth and the configuration of the ulcer, three or more of small pieces of human amniotic membranes are stacked one above the others to fill the cavity of the ulcer. Finally, a larger piece of membrane is trimmed to cover the ulcer and then secured with interrupted 10-0 nylon suture. RESULTS: The corneal perforations were prevented and the stable ocular surface were achieved in all patients. CONCLUSIONS: Human multilayer amniotic membrane transplantation is a useful treatment prior to corneal transplantation and considered as an alternative treatment to keratoplasty for perforation or impending perforation of corneal ulcer.
Amnion* ; Bowman Membrane ; Cornea ; Corneal Perforation ; Corneal Transplantation ; Corneal Ulcer* ; Epithelium ; Humans ; Membranes ; Nylons ; Sutures ; Ulcer

PURPOSE: To report the confocal morphological changes of keratoconus in comparison with that of normal cornea. METHODS: Confocal microscopy (ConfoScan 2.0, Fortune Technology, Italy) was used to obtain data from healthy volunteers and keratoconus. We evaluated corneal morphological images of the corneal epithelium, Bowman's layer, stromal layer (anterior, middle, and posterior keratocyte), Descemet's membrane, and endothelium. RESULTS: In keratoconus cornea, the wing cells of epithelium had somewhat irregular margin, and the subepithelial nerve bundle was slightly enlarged. Near Bowman's membrane, highly reflective changes and tear like structure were visible. While the anterior stromal keratocyte had nuclei with a highly reflective density and indefinite cell border, posterior keratocyte had a more distinct shape with less cellularity. Near descemet's membrane, vertical fold (Vogt's striae) was observed and keratocytes with long processes arranged nearly in parallel. Morphological change was not observed in the endothelium. CONCLUSIONS: Our confocal microscopic findings of keratoconus may help early diagnosis and assessment of prognosis in the management of keratoconus.
Bowman Membrane ; Cornea ; Descemet Membrane ; Early Diagnosis ; Endothelium ; Epithelium ; Epithelium, Corneal ; Healthy Volunteers ; Keratoconus* ; Microscopy, Confocal ; Prognosis

PURPOSE: To investigate the change of morphometric characteristics of the corneal cells by confocal microscopy in long-term soft contact lens wearer. METHODS: Confocal microscopy (ConfoScan 2.0, Fortune Technology, Italy) was used to obtain data from healthy volunteers and soft contact lens wearers for 10 years. We evaluated the morphological images of the corneal epithelium (superficial cell, wing cell), Bowman's membrane, stromal cells (anterior, middle, and posterior keratocyte), Descemet's membrane, and endothelium. RESULTS: In comparison with control, the wing cells from corneal epithelium of contact lens wearer appeared to have irregular and blurred cell borders, and enlarged subepithelial nerve plexus. The bowman's membrane and the anterior stroma showed an increased reflectivity. The keratocyte from a highly reflective area showed no definite cell border anteriorly and more distinct shape with less cellularity posteriorly. Descemet's membrane showed an evidence of vertical fold and keratocytes with long processes were arranged in parallel. The endothelial layer showed polymegathism and polymorphism with some gutta. CONCLUSIONS: According to these data, it would be suggested that a long-term wearing of soft contact lens could influence the morphology of corneal epithelium and stroma as well as of corneal endothelium.
Bowman Membrane ; Contact Lenses, Hydrophilic* ; Cornea* ; Corneal Stroma ; Descemet Membrane ; Endothelium ; Endothelium, Corneal ; Epithelium, Corneal ; Healthy Volunteers ; Microscopy, Confocal ; Stromal Cells

PURPOSE: Schnyder's dystrophy with severe corneal opacity need lamellar or penetrating keratoplasty. But recently, excimer laser is used to decrease the corneal opacity. So we performed excimer laser PRK in myopic SCD patient. METHODS: A 34-year-old female whose chief complaint was visual hazeness had multiple needle-shape crystalline deposit and disc-shaped opacity in Bowman's membrane and superficial corneal stroma in her both eyes. We diagnosed as Schnyder's dystrophy and performed PRK on her right eye. RESULTS: After PRK, visual improvement was achieved. We report this case with literature review as we believe that our case is the first report in our country.
Adult ; Bowman Membrane ; Corneal Opacity ; Corneal Stroma ; Crystallins ; Female ; Humans ; Keratoplasty, Penetrating ; Lasers, Excimer*

In the stratified squamous epithelium, most of basal cells in the entire epithelium function as stem cells. But many researchers report that stem cells in the corneal epithelium are located exclusively in the limbus. We planned to investigate the morphological characteristics of migrating corneal epithelial cells by the electron microscopy. Sprague-Dawley rats at fullterm, postnatal day 5, 10, 15, and adult were used as experimental animals. The results are as follows. 1. Stratification of the corneal epithelium : The number of layers in the corneal epithelium was dramatically increased in the period between postnatal day 10 and 15. 2. Migration of the corneal epithelial cells : In the groups of postnatal day 10 and adult, wide intercellular spaces were noted. Especially in the adult, the limbal side of basal cells was being lifted from the Bowman's membrane and centripetal polarity of them are noted. According to the above results, the wide intercellular spaces at postnatal day 10 seems to be resulted from the migration of corneal epithelial cells for epithelial stratification. The centripetal polarity of limbal basal cells in adult rat suggests that only the limbal basal cells may function as stem cells in that period.
Adult ; Animals ; Bowman Membrane ; Epithelial Cells* ; Epithelium ; Epithelium, Corneal ; Extracellular Space ; Humans ; Microscopy, Electron ; Rats* ; Rats, Sprague-Dawley ; Stem Cells

Laser in situ kratomileusis(LASIK) is a prefered method to excimer laser photorefractive keratectomy (PRK) because the former cuts only corneal stroma, while the latter cuts corneal epithelium, Bowmans membrane, and stroma, LASIK is a complex procedure composed of corneal flap preparation and photo-ablation. In corneal flap preparation, two types, manual and automatic, of microkeratomes have been used. We experienced problems during and after LASIK procedure using a manual microkeratome in learning curve period(8 months) and criticized the problems to shorten a learning curve of manual microkeratome. One hundred eighty six myopic eyes treated with LASIK using manual microkeratome(MLK, SCMD, USA) from January 1997 to August 1997 by one operator(Joo) were subjects. Problems occurred in 24 eyes(12.9%) and consisted of hole in corneal flap (5 eyes), thin corneal flap(3 eyes), winkling of corneal flap (2 eyes), hinge inside optical zone of laser(3 eyes), haze of interface (3 eyes), and free corneal flap(8 eyes). Majority of complications occurred in the first 3 months and most complicated cases were preventable when the speed of microkeratome enhancement was slow in late series of study. It seems that a manual microkeratome takes longer learning curve than automated microkeratome. Therefore, to decrease the number of problem cases in learning curve of LASIK using manual microkeratome a didatic course, advices from experienced surgeons, and participation in wet lab would be mandatory.
Bowman Membrane ; Corneal Stroma ; Epithelium, Corneal ; Keratomileusis, Laser In Situ* ; Lasers, Excimer ; Learning Curve ; Methods ; Photorefractive Keratectomy

This study was carried out to determine whether the autolytic changes of the hair, nail, and cornea were useful marker to estimate the postmortem interval. The hairs and nails obained from variable aged men and corneas from rabbits were placed in variable temperatures (10 degrees, 20 degrees, 30 degrees)and humidities (50%, 75%, 100%) and periodically investigated by electrom microscopy. The results were as follows. The hairs and nails were not significantly changed to 21 days after cut in variable temperatures and humidities. The cornea showed epithelial desquamation from the first day and endothelial desquamation from the third day. However, Bowman's membrane, stroma, and endothelial changes of the cornea were irregular on case. From the above results, it is concluded that the autolytic changes of the hair, nail and cornea were not useful to estimate the posmortem interval within a few weeks.
Bowman Membrane ; Cornea ; Hair* ; Humans ; Humidity ; Male ; Microscopy ; Rabbits

Reis-Bucklers' dystrophy is an autosomal dominant disorder involving Bowman's membrane. It usually appears as a recurrent corneal erosion in early childhood and is characterized by an irregular, semi-opaque accumulation of fibrous connective tissue in the area of Bowman's membrane and symmetrical progressive opacity of superficial central cornea. Eventually, it causes visual disturbance due to re-ticulated gray-white corneal opacity and corneal surface irregularity. The ophthalmic surgeons have met difficulties in the management of Reis-Bucklers' corneal dystrophy because of poor long-term results following conventional penetrating and lamellar keratoplasties. We experienced a case of Reis-Bucklers' dystrophy in 25 years old man which was confirmed by clinical and pathological evidences and successfully treated by excimer laser phototherapeutic keratectomy(PTK) with VISX 20/20 B(R). In conclusion, we would suggest that PTK could be another modality of management in this anterior corneal disease when surgical intervention is required.
Adult ; Bowman Membrane ; Connective Tissue ; Cornea ; Corneal Diseases ; Corneal Opacity ; Corneal Transplantation ; Humans ; Lasers, Excimer

The patients initially underwent epikeratoplasty for keratoconus but a penetrating kerato plasty was required due to the opacity in the cornea. By using of this specimen, which was obtained by trephination the healing process of the host-Ienticule cornea could be examined by electron microscopy and immunofluorescence method. Epithelial ingrowth over the lenticule was well formed by the regeneration of the basement membrane over the Bowman's membrane. However, the poor attachment of the lenticule over the host corneal stroma made the interface easily separated during the sectioning processes. Electron microscopic study revealed the keratocytes in the lenticule stroma vacuolized with large number of degenerated microorganelles. These results suggest that it may take a long time to complete the wound healing of the host-Ienticule interface despite the epithelial ingrowth onto the lenticule was well formed.
Basement Membrane ; Bowman Membrane ; Cornea ; Corneal Stroma ; Epikeratophakia* ; Extracellular Matrix ; Fluorescent Antibody Technique ; Humans ; Keratoconus ; Microscopy, Electron ; Regeneration ; Trephining ; Wound Healing