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At least 19 recordsLinked to original sources
PubMed2003

[Experimental study of the influence of cornea flap and residual cornea bed on cornea intensity after LASIK].

OBJECTIVE: To study the influence of cornea flap and residual cornea bed on cornea intensity after laser in situ keratomileusis (LASIK). METHODS: The established mature cats animal model of LASIK was used. In Group A, a 160 micro m cornea flap was made, followed by performing ablation on the stroma by excimer laser to preserve the residual bed for 300 micro m, and then the cornea flap was repositioned. The cornea flap was removed with the residual bed 300 micro m remaining in Group B, while in Group C, a 160 micro m cornea flap was made with the residual bed 180 micro m, and followed reposition of the cornea flap. In Group D, the cornea flap was cut off and a 180 micro m the residual bed was remained. Measurements included central cornea pachymetry, anterior chamber depth (ACD) and analysis of the posterior best fit sphere in cornea Topography before operation and 1 week, 1 month, 2 months and 3 months after operation. The results were analyzed statistically. 3 months after operation, the changes of cornea structures were observed by histopathological analysis and transmission electron microscope. RESULTS: Increase of ACD 3 months after operation: Group A, (0.16 +/- 0.08) mm; group B, (0.21 +/- 0.16) mm; group C, (0.33 +/- 0.09) mm; group D, (0.41 +/- 0.10) mm. There was no statistical difference between group A and group B (t = 0.685, P > 0.05) and between group C and group D (t = 1.457, P > 0.05). There was a statistical difference between group A and group C (t = 3.458, P < 0.05) and between group B and group D (t = 2.597, P < 0.05). Increase of posterior cornea prominence 3 months after operation: Group A, (27.78 +/- 9.52) micro m; group B, (39.57 +/- 7.68) micro m; group C, (58.57 +/- 8.66) micro m; group D, (68.14 +/- 19.69) micro m. No statistical difference was found between group A and group B (t = 2.361, P > 0.05) and group C and group D (t = 1.090, P > 0.05). There was a statistical difference between group A and group C (t = 5.860, P < 0.05) and between group B and group D (t = 3.310, P < 0.05). Light microscopy and transmission electronic microscopy showed that the arrangements of collagen fiber in the interface were disordered with no apparent cross arrangement. There was no significant increase of rough endoplasmic reticulum in fibroblast. CONCLUSIONS: The residual cornea bed is the main factor to influence corneal intensity. After LASIK, the wound healing of the interface is different from scar. This may be the main reason for cornea flap's no apparent influence on cornea intensity.

Animals↗
PubMed1962

Studies on the cornea. I. The fine structure of the rabbit cornea and the uptake and transport of colloidal particles by the cornea in vivo.

Physiological studies have demonstrated that ions, as well as large molecules such as hemoglobin or fluorescein, can diffuse across and within the cornea. Most of the substrates for corneal metabolism are obtained from aqueous humor filling the anterior chamber. In order to receive its nutrients and in order to maintain its normal conditions of hydration, the avascular cornea must transport relatively large amounts of solute and solvent across the cellular layers which cover this structure. It has been suggested in the past that there may be a morphological basis for the transport of large amounts of solvents and solutes by cells by the mechanism of pinocytosis. The use of electron-opaque markers to study fluid movements at the electron microscope magnification level was described by Wissig (29). The present study describes the fine structure of the normal rabbit cornea and the pathways of transport of colloidal particles by the cornea in vivo. Rabbit corneas were exposed in vivo to suspensions of saccharated iron oxide, thorium dioxide, or ferritin by injection of the material into the anterior chamber. In other experiments thorium dioxide or saccharated iron oxide was injected into the corneal stroma, producing a small bleb. Particles presented at the aqueous humor surface of the rabbit corneal endothelium are first attached to the cell surface and then pinocytosed. It appears that the particles are carried around the terminal bar by an intracellular pathway involving the pinocytosis of the particles and their subsequent transport in vesicles to the lateral cell margin basal to the terminal bar. Particles introduced at the basal surface of the endothelium (via blebs in the corneal stroma) are apparently carried through the endothelial cells in membrane-bounded vesicles without appearing in the intercellular space. There appears to be free diffusion of these particles through Descemet's membrane and the corneal stroma. The stromal cells take up large quantities of the particles when blebs are injected into the stroma.

Animals↗
PubMed1962

Studies on the cornea. III. The fine structure of the frog cornea and the uptake and transport of colloidal particles by the cornea in vivo.

The fine structure of the frog cornea has been studied and compared with that of the rabbit cornea (1, 2) particularly in relation to the uptake and transport of colloidal particles. The frog corneal endothelium does not possess a terminal bar and the fluid space of the intercellular space is apparently continuous with that of the anterior chamber. Colloidal markers (ThO(2), Fe(2)O(3)) placed in the anterior chamber pass down the intercellular space into the cornea. Markers injected intrastromally diffuse freely in the stroma and Descemet's membrane but pass across the endothelium only via membrane-bounded vesicles. These results are compared with those of similar experiments in the rabbit and it is concluded that the primary pathway for the passage of materials into the cornea is intercellular and that the pinocytotic pathway of the rabbit corneal endothelium (Kaye and Pappas; Kaye et al.) is an adaptation to the presence of a terminal bar. The significance of the separation of inward and outward pathways in terms of corneal metabolism is considered.

Animals↗
PubMed2003

Human diabetic corneas preserve wound healing, basement membrane, integrin and MMP-10 differences from normal corneas in organ culture.

The authors have previously documented decreased epithelial basement membrane (BM) components and alpha3beta1 epithelial integrin, and increased expression of matrix metalloproteinase (MMP)-10 in corneas of patients with diabetic retinopathy (DR) compared to normal corneas. The purpose of this study was to examine if organ-cultured DR corneas exhibited the same alterations in wound healing and diabetic marker distribution as the autopsy DR corneas. Twenty normal and 17 DR corneas were organ-cultured in serum-free medium over agar-collagen gel at the air-liquid interface for up to 45 days. Circular 5 mm central epithelial wounds were made with n-heptanol, the procedure that will preserve fragile diabetic corneal BM. Wound healing was monitored microscopically every 12 hr. Distribution of diabetic corneal epithelial markers including laminin-10 alpha5 chain, nidogen-1/entactin, integrin alpha3beta1, and MMP-10, was examined by immunofluorescence. Normal corneas healed the central epithelial defect within 3 days (mean=2.3 days), whereas DR corneas on average healed about two times slower (mean=4.5 days). In wounded and completely healed organ-cultured corneas, the patterns of studied markers were the same as in the unwounded organ-cultured corneas. This concerned both normal and DR corneas. As in vivo, normal organ-cultured corneas had continuous staining for laminin-10 and nidogen-1/entactin in the epithelial BM, strong and homogeneous staining for both chains of alpha3beta1 integrin in epithelial cells, and little if any staining for MMP-10. Organ-cultured DR corneas also had marker patterns specific for in vivo DR corneas: interrupted to no staining for laminin-10 and nidogen-1/entactin in the epithelial BM, areas of weak or disorganized alpha3beta1 integrin in epithelial cells, and significant MMP-10 staining in the epithelium and keratocytes. Fibrotic extracellular matrix and myofibroblast markers were largely absent. Thus, epithelial wound healing was much slower in organ-cultured DR corneas than in normal corneas, in complete accordance with clinical data in diabetic patients. DR corneas in organ culture preserved the same marker abnormalities as in vivo. The marker distribution was unchanged in wounded and healed organ-cultured corneas, compared to unwounded corneas. The established corneal organ culture provides an adequate system for elucidating mechanisms of epithelial alterations in human DR corneas.

Aged↗
PubMed2002

Extracellular matrix and Na+,K+-ATPase in human corneas following cataract surgery: comparison with bullous keratopathy and Fuchs' dystrophy corneas.

PURPOSE: To examine the distribution of extracellular matrix (ECM) and basement membrane (BM) components and of Na+,K+-ATPase in postcataract surgery (PCS) corneas. These corneas were from patients who never developed pseudophakic or aphakic bullous keratopathy (PBK/ABK) after cataract surgery. PCS corneas were compared with PBK/ABK and Fuchs' dystrophy corneas. METHODS: The distribution of PBKIABK ECM and BM markers and of all three Na+,K+-ATPase alpha subunits was studied by immunofluorescence in 10 healthy, 11 PCS, 16 PBK/ABK, and 12 Fuchs' dystrophy corneas. RESULTS: Fibrotic ECM proteins, tenascin-C and fibrillin-1, were found in only 1 of 10 healthy and in 2 of 11 PCS corneas. In contrast, these proteins were expressed in all PBK/ABK and more than half of the Fuchs' dystrophy corneas. BM components in PCS corneas were altered to a greater extent (40-60%), especially fibronectin and laminin-10. A decreased epithelial immunostaining for Na+,K+-ATPase alpha subunits was seen in approximately 40% of PCS corneas and in approximately two thirds of PBK/ABK and Fuchs' dystrophy corneas. However, the endothelial staining was normal in all groups. CONCLUSIONS: Because tenascin-C and fibrillin-1 were mostly found in diseased but not in PCS corneas, their expression may be related to later, clinical stages of corneal edema development. However, BM components abnormal in PBK/ABK and Fuchs' dystrophy corneas were also altered in PCS corneas without clinical evidence of ocular disease. This may result from subclinical corneal changes resulting from cataract surgery, lens removal, exposure to the intraocular lens, or endothelial cell damage. Alterations of epithelial Na+,K+-ATPase point to the importance of epithelial changes in the development of corneal edematous diseases.

Basement Membrane↗
PubMed1999

The distribution of gentamicin in the rabbit cornea following iontophoresis to the central cornea.

The purpose of this study was to evaluate the penetration of gentamicin into the central, midperipheral and peripheral cornea of rabbits following iontophoresis to the central 3 mm of the cornea. Four groups (groups 1-4) of five rabbits (one eye per rabbit) underwent corneal iontophoresis using gentamicin dissolved in agar. Low (1 mg/ml) and high (10 mg/ml) concentrations of gentamicin in agar were used for one or ten minutes. Two control groups (groups 5 and 6) of five eyes each underwent mock iontophoresis with low and high concentrations of agar-gentamicin mixture. Following sacrifice of the rabbits, the central, midperipheral and peripheral parts of each cornea were excised. Gentamicin concentration was determined in each part of every cornea. High concentrations of gentamicin (951.6 +/- 369.4 microg/ml to 26.6 +/- 41.34 microg/ml) were obtained in the central parts of all the iontophoresis-treated corneas. In each group, except group 6, central corneas had higher concentrations of gentamicin compared to midperipheral corneas (p = 0.038 to p = 0.021), and midperipheral corneas had higher levels than peripheral corneas (p = 0.038 to p = 0.021). Following iontophoresis, gentamicin is found in all portions of the corneas; however, the highest concentration of the drug remains in the central cornea.

Analysis of Variance↗
PubMed1999

Corneal thickness, intraocular pressure, and optical corneal diameter in Rocky Mountain Horses with cornea globosa or clinically normal corneas.

OBJECTIVE: To compare corneal thickness, intraocular pressure, and optical corneal diameter in Rocky Mountain Horses with cornea globosa and those with clinically normal corneas. ANIMALS: 129 Rocky Mountain Horses. PROCEDURE: Ultrasonic pachymetry was used to measure corneal thickness. Applanation tonometry was used to measure intraocular pressure. A Jameson caliper was used to measure optical corneal diameter. RESULTS: The central and temporal peripheral portions of the cornea were significantly thicker in horses with cornea globosa than in horses with clinically normal corneas, but corneal thicknesses in the dorsal, ventral, and medial peripheral portions of the cornea were not significantly different between groups. There were no differences in corneal thickness between male and female horses or between right and left eyes. However, there was a positive correlation between age and corneal thickness. Intraocular pressure was not significantly different between horses with cornea globosa and those with clinically normal corneas, or between right and left eyes, or male and female horses. Optical corneal diameter for horses with cornea globosa was not significantly different from diameter for horses with clinically normal corneas, but optical corneal diameter was positively correlated with age. CONCLUSIONS AND CLINICAL RELEVANCE: Cornea globosa in Rocky Mountain Horses is not associated with increased intraocular pressure. Corneal thickness and optical corneal diameter increase with age in Rocky Mountain Horses.

Aging↗
PubMed1995

Keratocyte gap junctional communication in normal and wounded rabbit corneas and human corneas.

PURPOSE: Several studies have indicated the anatomic and biochemical presence of gap junctions in corneal keratocytes. The current study was designed to demonstrate that these gap junctions are functional in rabbit and human corneal keratocytes. This study also examined dye coupling between keratocytes migrating into the wound region of freeze-wounded rabbit corneas. METHODS: Freeze wounds were created on anesthetized rabbit corneas using a liquid nitrogen-cooled brass probe. Freeze-wounded corneas were examined at several time periods from days 0 to 5 after wounding. Nonwounded rabbit corneas also were examined. Human corneal buttons were examined immediately after removal from patients who underwent keratoplasty. Gap junctional coupling was examined by microinjecting carboxyfluorescein from microelectrodes into the basal-most keratocytes and capturing dye spread images with a cooled charge coupled device camera. RESULTS: Significant dye spread was observed between cells in the unwounded areas of corneas at wound time 0 and between cells migrating into the wound areas as early as 24 hours after wounding. In control corneas, dye spread to as many as 50 cells from the source cell. Dye spread also was seen between keratocytes in human corneas with pseudophakic bullous keratopathy and keratoconus. CONCLUSIONS: Gap junctions observed in keratocytes from normal rabbit corneas are functional. Gap junctions also are present and functional in keratocytes within unwounded and wounded regions of freeze-injured corneas. In addition, functional gap junctions are present between keratocytes in human corneas. This study confirms the long-held contention that corneal keratocytes form a large intercommunicating network within the corneal stroma.

Adult↗
PubMed2000

Immunobiology of xenogeneic cornea grafts in mouse eyes. I. Fate of xenogeneic cornea tissue grafts implanted in anterior chamber of mouse eyes.

BACKGROUND: The cornea is an immune privileged tissue that, when grafted orthotopically, forms the anterior surface of the immune privileged anterior chamber. We have recently reported that allogeneic cornea fragments implanted in the anterior chamber of mouse eyes resist immune rejection, although such graft fragments are rejected outside the eye. We wished to determine the extent to which xenogeneic cornea fragments placed in the eyes of normal mice are vulnerable to immune rejection. METHODS: Guinea pig corneas, deprived surgically of epithelium, were cut into fragments and inserted into the anterior chamber of eyes of BALB/c and severe combined immune deficient (SCID) mice, adjacent to the central cornea of the recipient. The fate of the grafts was assessed clinically by biomicroscopy and histologically for 8 weeks postimplantation. RESULTS: The majority of guinea pig cornea fragments devoid of epithelium came to rest with the raw stroma adjacent to recipient endothelium. These fragments remained clear for the 8-week observation interval in both BALB/c and severe combined immune deficient mice. Clear grafts displayed viable guinea pig keratocytes and endothelial cell layers for 4 weeks. The endothelium was then replaced by murine cells by 8 weeks. A minority of guinea pig cornea fragments were oriented with donor endothelium adjacent to recipient endothelium. Although these grafts in severe combined immune deficient eyes eventually acquired an endothelial layer that faces the anterior chamber and remained clear, similar fragments in BALB/c eyes became opaque, failed to acquire a proper lining of endothelium that faces the anterior chamber, and incited an inflammatory reaction in adjacent recipient cornea. CONCLUSIONS: Immune privilege is afforded to xenografts of guinea pig cornea placed as stromal: endothelial cell fragments in the anterior chamber of mouse eyes, but only if the surface of the fragments that faces the anterior chamber is promptly covered with corneal endothelium. The possible roles of corneal endothelium in promoting immune privilege of corneal xenografts are discussed.

Animals↗
PubMed2000

Effects of penetrating keratoplasty rejection on the endothelium of the donor cornea and the recipient peripheral cornea.

PURPOSE: To determine the effects of penetrating keratoplasty rejection on the recipient endothelium. METHODS: Twenty transplanted corneas of 20 keratoconus patients were enrolled in this study. Ten of the corneas had undergone allograft rejection and the other 10 grafts had an uneventful postsurgical course. The endothelium of the donor cornea and the endothelium of the recipient peripheral cornea were evaluated by wide-field specular microscopy. RESULTS: The transplanted corneas that underwent allograft rejection showed a marked decrease in endothelial cell density not only in central donor cornea but also in the recipient peripheral cornea compared with that in the uneventful transplanted corneas. Additionally, the recipient endothelium had significant pleomorphism in the rejection group. There were no morphologic differences in the peripheral donor cornea between the control group and the rejection group. CONCLUSIONS: Our findings indicate that the recipient peripheral endothelium is also affected by allograft rejection, perhaps because of the contribution of recipient endothelium to the wound healing process after allograft rejection.

Adult↗
PubMed1981

Secondary lens formation from the cornea following implantation of larval tissues between the inner and outer corneas of Xenopus laevis tadpoles.

Secondary lens formation from the cornea of larval Xenopus laevis has been used as a measure of the lens-inducing capacities of various larval Xenopus tissues. The experimental design employed involved implantation of selected body tissues between the inner and outer cornea of stage-50 tadpole eyes, in such a way that the integrity of the inner cornea and eye cup was not disrupted. Implantation of retina, pituitary, limb blastema or limb bud resulted in secondary lens formation from the outer cornea. Such lenses were similar in appearance to stage-5 lens regenerates described by Freeman (1963). No secondary lenses were observed in eyes receiving either heart or hind brain implants or in eyes which underwent corneal separation but which received no implant. It is concluded that the retina is the natural source of a stimulatory factor which initiates and maintains corneal transformation to lens during lens regeneration following lensectomy. Influences emanating from pituitary, limb blastema and limb bud, but apparently not from heart or hind brain, are able to act on cornea in a way similar to the retinal factor. Furthermore, our findings support the contention that in the normal eye, the inner cornea is a barrier to the passage of retinal factor and so maintains the single lens structure of the eye. When this barrier is by-passed by lens-inducing tissue, as in the present experimental design, lens formation from the cornea is able to take place. Electronmicroscopical studies have shown that the inner cornea, in the stage-50 tadpole eye, consists of a dense meshwork of collagen fibrils and a basal layer of cohesive elongated mesenchymal cells well suited for this barrier function.

Animals↗
PubMed1986

Aqueous to cornea fluorescein distribution ratio in normal and swollen cornea.

Intravitreal sodium fluorescein was used to simulate equilibrium fluorescein kinetics, thereby allowing simple measurement of the aqueous to cornea fluorescein distribution ratio. Two groups of rabbit corneas were studied: normal corneas and corneas wounded by freezing. The aqueous to cornea fluorescein distribution ratio was approximately 0.4, was not significantly different in groups of normal or wounded eyes and little variability was noted. In addition, a comparison of in vivo and in vitro measurements of corneal fluorescein concentration in wounded eyes suggests that in vivo protein-bound fluorescein in the cornea fluoresces less efficiently than free fluorescein.

Animals↗
PubMed2002

Cornea procurement from very old donors: post organ culture cornea outcome and recipient graft outcome.

AIM: To study the suitability of corneas from very old donors for graft after banking and their clinical and endothelial outcomes in recipients. METHODS: 419 corneas stored in organ culture were divided into group 1, donors under 85 years (330 corneas) and group 2, "very old" donors aged 85 years and over (89 corneas). Endothelial cell density (ECD) before and after organ culture, discard rate before and after storage, and clinical and endothelial outcomes of the 196 penetrating keratoplasties (PKP) (158 in group 1 and 38 in group 2) were compared in a prospective longitudinal study. RESULTS: Initial ECD was lower in group 2 than in group 1 and elimination for low ECD was more frequent in group 2 (respectively 38% v 20.2%, p=0.001). At the end of storage, because very old corneas lost fewer ECs than younger ones (respectively 4.2% v 9.5%, p=0.022), ECD was comparable between the two groups. The corneas of very old donors had a poorer macroscopic appearance at procurement and during surgery. Despite this, in grafted patients, overall graft survival in groups 1 and 2 (respectively 87.4% v 80.6%, p=0.197), visual acuity, and ECD did not differ at completion of the study (mean follow up 25 months). CONCLUSION: This study suggests that endothelial cell count during banking ensures that functional and cellular results of PKPs are not dramatically influenced by very old donor age. Considering Europe's ageing population, the very elderly should not be deemed off limits for corneal procurement.

Adolescent↗
PubMed1997

Cornea refractive changes after clear cornea phacoemulsification with foldable intraocular lens.

BACKGROUND: Clear cornea incision for phacoemulsification is the current trend of cataract surgery, with the benefits of small incision, quick rehabilitation and stable wound architecture. In our Oriental eyes with small palpebral fissure the cornea curvature is easily affected by the tight lid compression. Evaluation of the postoperative cornea topographic change after this procedure in our patient is thus necessary. METHODS: Forty eyes with simple cataract were enrolled in this study. Among them 22 were right eyes and 18 were left eyes. All of them were through temporal clear cornea incision. A 2.65 mm length incision for phacoemulsification then enlarged to 3.5 mm for foldable intraocular lens implantation. The wound remained self-healing without suture. Color topographies were taken before and then one and three months after surgery. Palpebral fissures were measured before surgery. RESULTS: Induced cornea astigmatism measured as 0.30 +/- 0.35 diopter in the first postoperative month, and 0.50 +/- 0.43 diopter in the third postoperative month. All the induced astigmatism was toward the incision axis and with the rule shifting. CONCLUSIONS: Tolerable with-the-rule astigmatism shifting around 0.5 diopter was noted postoperatively via temporal clear cornea phacoemulsification with foldable intraocular lens implantation in our patients.

Aged↗
PubMed1996

Conjunctival epithelial cells can resurface denuded cornea, but do not transdifferentiate to express cornea-specific keratin 12 following removal of limbal epithelium in mouse.

Limbal stem cell deficiency contributes to recurrent corneal epithelial defects. We examined whether the conjunctival epithelium can transdifferentiate to corneal epithelium following surgically induced limbal stem cell deficiency. Mice were anesthetized by intraperitoneal injection of sodium pentobarbital. Partial or total epithelial removal was produced with a no. 69 Beaver blade under a dissecting microscope. The wounds were allowed to heal for 0-28 days, and the mice were examined every other day to evaluate re-epithelialization. Corneas were then subjected to histological, immunohistochemical studies and Western blot analysis with epitope-specific anti-keratin 12 antibodies. Partial epithelial defects re-epithelialized within 2 days and were normal in appearance and expressed cornea-specific keratin 12. In eyes with limbal deficiency, re-epithelialization progressed more slowly and was characterized by opacification; epithelial closure usually occurred by the 7th day. This epithelium differed from normal corneal epithelium in basic morphology, cell shape, and the presence of goblet cells at 2 weeks after injury. The epithelium at the center of injured corneas with total defect at 4 weeks had cornealike morphology and was devoid of goblet cells. These epithelial cells derived from conjunctiva did not express the cornea-specific keratin 12 as determined by immunohistochemistry, Western blot analysis and in situ hybridization. As evidenced by differences in morphology and the expression of cornea-specific keratin 12, conjunctival transdifferentiation does not occur in conjunctical overgrowth after the removal of limbal epithelium.

Amino Acid Sequence↗
PubMed1997

Comparison of astigmatism after penetrating keratoplasty by experienced cornea surgeons and cornea fellows.

PURPOSE: We compared surgically induced astigmatism after penetrating keratoplasty performed by supervised cornea fellows and experienced cornea surgeons. METHODS: Data were collected by retrospective chart review of 166 cases (166 eyes) of penetrating keratoplasty: 63 performed by two cornea surgeons and 103 by four cornea fellows. Astigmatism was calculated using scalar and vector methods. Vector analysis was performed on 109 of 166 eyes. Two techniques were compared: intraoperative keratometry and suture adjustment and the torque-antitorque running suture technique with no intraoperative keratometry or suture adjustment. RESULTS: Mean surgically induced scalar astigmatism changed from preoperative astigmatism by 3.27 diopters (fellows) and 2.94 diopters (attending surgeons). In 109 cases, surgically induced vector cylinder changed from peroperative astigmatism by 4.21 diopters at 98 degrees (fellows) and 4.25 diopters at 114 degrees (surgeons). Surgically induced vector astigmatism changed from preoperative astigmatism by 4.67 diopters at 93 degrees in the first 6 months (fellows) and by 3.79 diopters at 103 degrees in the second 6 months. Analysis of x-axis and y-axis components of the surgically induced vector cylinder showed that the majority of the astigmatism was induced in the y-axis and that this difference was significant (P < .001) in all comparisons, independent of technique or surgeon group. CONCLUSIONS: Penetrating keratoplasty performed by supervised cornea fellows resulted in similar rates of surgically induced vector astigmatism, surface asymmetry, and surface regularity as that by experienced surgeons. Fellows induced significantly more with-the-rule astigmatism, but this tendency decreased with further training. Penetrating keratoplasty astigmatic outcomes were not significantly different whether or not intraopertive keratometry and suture adjustment were utilized. This study supports the concept that increased experience with corneal transplantation improves the outcome of penetrating keratoplasty by using the criterion of postoperative astigmatism as a measures.

Astigmatism↗