摘要:

Purpose.Intraocular pressure (IOP) measurements vary with different tonometers in irregular corneas. The purpose of our study was to determine the comparability of the ocular blood flow tonometer (OBF) and Tonopen with the Goldmann applanation tonometer (GAT) in measuring IOP in post-keratoplasty eyes.Methods.The IOP was measured using the OBF tonometer, GAT, and Tonopen in 69 post-keratoplasty eyes by two observers. The same instruments were used, and the sequence of measurements was randomized. Pachymetry to measure corneal thickness was done in all patients.Results.Interobserver variation for IOP measured with GAT was statistically significant (p= 0.039). Two-way analysis of variance (ANOVA), however, did not demonstrate any statistical difference between measurements with the three tonometers and two observers. Corneal thickness did not appear to have an effect on measurements with any of the tonometers.Conclusion.There was no significant difference in the overall accuracy of the OBF tonometer over the Tonopen versus the GAT. The OBF tonometer can be a useful alternative in measuring IOP in post-keratoplasty eyes.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To report a case series of the first clinical application of a new method of astigmatic keratotomy termed full-arc, depth-dependent astigmatic keratotomy (FDAK).Methods.The type of astigmatism was analyzed by corneal topography. If the astigmatism was regular, paired arcuate incisions of 90° length were used. Incision depth varied between 40% and 75% of local corneal thickness for controlling the level of astigmatic correction.Results.All 13 cases had regular astigmatism, and paired arcuate incisions of 90° length were used. Four cases with incisions at 40% depth, five cases at 50% depth, three cases at 60% depth, and one case at 75% depth induced vector astigmatic change of 0.93 ± 0.33 D, 1.92 ± 0.24 D, 3.17 ± 0.26 D, and 4.44 D, respectively, 3 months after surgery. From 3 months to 1 year or 3 years, the postoperative astigmatism was stable, and no cases showed astigmatic regression of 0.50 D or more. Every topographic difference map indicated effective flattening and steepening occurring with a 1:1 coupling ratio. All postoperative color maps showed a marked improvement in corneal sphericity.Conclusions.In FDAK using paired 90° incisions at 40–75% depth, an almost linear relationship between the incision depth and degree of astigmatic change was observed. FDAK may be an effective and safe method of astigmatic keratotomy that accurately controls the level of astigmatic correction. More clinical applications are necessary for drawing final conclusions and making a nomogram.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Mutations in theBIGH3gene on chromosome 5q31 cause four distinct autosomal dominant corneal dystrophies. We sought to determine whether theBIGH3gene mutation was responsible for corneal dystrophy in Korean patients.Methods.Polymerase chain reaction single strand conformational polymorphism (PCR-SSCP) analysis was performed with the DNA from patients and healthy individuals. We sequenced the PCR products with the aberrant SSCP pattern to identify the mutation. Mutant-specific reverse primers were used to screen genomic DNA for the identified mutations.Results.We identified mutations R124C in the CDL1 family and R124H in four families with a granular dystrophy. We identified our granular dystrophy to be Avellino corneal dystrophy (ACD). Eighteen of 20 patients with a granular dystrophy contained the same R124H mutation, indicating that mutation R124H was very common in Korean patients with ACD. During this study, we identified a new polymorphism (T1667C, F540F).Conclusions.This is the first report of mutations found in theBIGH3gene in Korean families with corneal dystrophy. We report that the majority (90%) of ACD patients in Korea carry the R124H mutation. Mutant-specific reverse primers can be used to screen efficiently for CDL1 and ACD.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To report three cases of seemingly unilateral dystrophy indistinguishable from type I classic lattice corneal dystrophy.Methods.Case study of three patients. Three patients, a 31-year-old man, a 44-year-old woman, and a 41-year-old man had multiple lattice lesions in one eye and an apparently healthy fellow eye. Two of these patients underwent penetrating keratoplasty because of poor vision.Results.Histopathologic examination of the excised corneal button of patient 2 showed amyloid deposits consistent with lattice. In the third patient, lattice lesions were noted in the other eye nearly 13 years after he was first examined.Conclusions.Lattice corneal dystrophy is rarely unilateral. Lattice, even in unilateral cases, may cause significant vision loss to warrant penetrating keratoplasty. Lattice lesions may develop in the fellow eye many years later. This possibility should be explained to all patients with apparently unilateral lattice corneal dystrophy.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

It is accepted that the taxon-specific, multifunctional crystallins (small heat-shock proteins and enzymes) serve structural roles contributing to the transparent and refractive properties of the lens. The transparent cornea also accumulates unexpectedly high proportions of taxon-specific, multifunctional proteins particularly, but not only, in the epithelium. For example, aldehyde dehydrogenase 3 (ALDH3) is the main water-soluble protein in corneal epithelial cells of most mammals (but ALDH1 predominates in the rabbit), whereas gelsolin predominates in the zebrafish corneal epithelium. Moreover, some invertebrates (e.g., squid and scallop) accumulate proteins in their corneas that are similar to their lens crystallins. Pax-6, among other transcription factors, is implicated in development and tissue-specific gene expression of the lens and cornea. Environmental factors appear to influence gene expression in the cornea, but not the lens. Although no direct proof exists, the diverse, abundant corneal proteins may have evolved a crystallinlike role, in addition to their enzymatic or cytoskeletal functions, by a gene sharing mechanism similar to the lens crystallins. Consequently, it is proposed that the cornea and lens be considered as a single refractive unit, called here the “refracton,” to emphasize their similarities and common function.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To evaluate the percentage of corneas with an epithelial surface quality sufficient for a reliable screening of donor eyes with keratoconus and after photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) treatment for refractive errors. The usefulness of the computer-assisted, video-keratography system Keratron Scout in making this determination was evaluated.Methods.Forty eyes from 20 donors were screened within 30 minutes after enucleation and within 24 hours postmortem. At first a meticulous slit-lamp evaluation of the corneal surface and stroma was performed; thereafter eight pictures per eye were taken with the Keratron Scout, and an ultrasound pachymetry reading of the corneal center was taken. “True curvature,” algorithm-based color maps were used for analysis. Epithelium was not removed, because all corneas were suitable for transplantation. Balanced salt solution was used to keep the corneas moist. The low intraocular pressure regularly found in postmortem eyes was raised to within normal ranges by intravitreal injection. Corneas were classified according to the integrity of their epithelial surface, which influences the regularity of the topography maps.Results.The quality of the images acquired varied, depending mostly on the quality of the epithelium. Regular topography patterns were found in 15 eyes (37.5%); in 14 eyes (35%), minimal epithelial roughness or sloughing in just one quadrant of the cornea was detected. Moderate to severe epithelial irregularities or defects were found in nine eyes (22.5%). Screening for abnormal shape was possible in 90% of the tested eyes, where no changes caused by prior refractive surgery or keratoconus were apparent.Conclusion.The postmortem quality of the epithelial surface allows screening for keratoconus or refractive procedures in the majority of donor eyes. Video-keratography with the Keratron Scout seems to offer a sensitive and quick method for this purpose, thereby adding an additional safety feature to eye banking in view of the rapid development of corneal refractive surgery.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To determine the effect of scleral fixation ring placement in induction of astigmatism by topographic analysis.Methods.Baseline measurements were used in human eyes from the Utah Lions Eye Bank. In two control eyes, the effect of placing and replacing the eye in the holder was determined. In nine eyes, the effect of placing a 14-mm ring 2.0-mm from the limbus and an 18-mm ring 4.0-mm from the limbus, both in line with and between the rectus muscles, was determined. Induced astigmatism (IA) was determined by Alpins' vector analysis method.Results.Control eyes had a mean variation of 0.26 ± 0.18 diopters (D) (range, 0.07–0.65). The study eyes had a mean IA of 1.55 D with statistically significant differences noted when comparing 14-mm rings (0.92 ± 2.00 D) versus 18-mm rings in line with the rectus (3.02 ± 1.49 D;p= 0.02), with 18-mm rings in line with the rectus muscles (3.02 ± 1.46 D) versus between the muscles (1.37 ± 1.14 D;p= 0.03), and all measurements with the 14-mm ring (1.0 ± 1.49 D) versus the 18-mm ring (2.14 ± 1.51 D;p= 0.04.).Conclusions.Significant IA can occur with placement of fixation rings, especially when suture placement is near the insertions of the rectus muscles.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.Incisions in radial keratotomy (RK) patients were examined histopathologically to explore the cause of delayed infections occurring following this procedure.Methods.Four corneas from two successful RK patients were obtained postmortem and 1 cornea from an unsuccessful RK was collected following lamellar keratoplasty. The tissue was prepared for light and transmission electron microscopy.ResultsAll incisions examined contained an epithelial plug. The average depth of the plugs for left and right corneas in the 2 successful cases were 142.58 &mgr;m (range: 36.46–183.04 &mgr;m) and 58.44 &mgr;m (range: 29.27–115.66 &mgr;m), whereas the unsuccessful case these measurements were 121.06 &mgr;m (range: 70.03–172.01 &mgr;m). In the successful cases, the plugs were on average 4.2 cells deep (range: 2–5) in one case and for the other the plugs were 8.78 cells deep (range: 1.5–11.5) and 2.72 cells wide (range: 2–4). In the unsuccessful case the plugs were on average 6.89 cells deep (range: 5–11) and 8.56 cells wide (range: 4–13). The average epithelial thickness, measured 200 &mgr;m on either side away from the plug, was 47.11 &mgr;m and 55.09 &mgr;m for the successful cases, and 27.52 &mgr;m for the unsuccessful case. Degenerate cells were often observed within the plug and along the overlying surface. Lamellae cut during surgery remained severed in all corneas observed. The stroma adjacent to the incision contained an elevated number of stromal cells (8%–78%).Conclusions.Healing did not include repair of anterior limiting lamina or stromal lamellae, which all remained severed in all incisions observed. Epithelial plugs were invariably present in all incisions regardless of clinical outcome, thus, increasing the distance a basal cell travels to reach the epithelial surface by 2 to 4 times. Since the epithelial cell has a limited life, it is hypothesized that cells originating in the plug may die before reaching the surface, thus, leading to intermittent loss of surface integrity. The loss of the epithelial barrier allows invasion of microorganisms and the delayed onset of keratitis. The larger the plug the greater the possibility of surface defects and resultant infection.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.MUC5AC has been identified as a major secretory mucin of conjunctival goblet cells and precorneal tear film. However, no method has been reported to quantify MUC5AC protein in human tears. The objective of this study was to establish a method to measure the amount of MUC5AC in human tears and to correlate the amount of MUC5AC with age, gender, and dry eye diseases.Methods.A goat antibody was raised to synthetic peptides corresponding to nonglycosylated epitopes of human MUC5AC mucin. This antibody and a horseradish peroxidase-coupled second antibody were used to develop a quantitative immunoassay to measure the MUC5AC concentration of tear samples collected on Schirmer strips. Porcine stomach mucin was used as a standard for the assay. The chemiluminescent MUC5AC signal was digitized and quantified. Tear samples from 19 healthy volunteers and 31 clinically diagnosed dry eye patients were analyzed.Results.MUC5AC concentration in human tears ranged from undetectable to more than 200 &mgr;g/mL porcine stomach mucin equivalent. In the healthy population, low, moderate, and high concentrations were found in the tear samples from younger and older persons and from both men and women. The mean MUC5AC content in tears was lower in the dry eye patients than in the age- and gender-matched healthy individuals.Conclusions.A method was established to quantify MUC5AC in human tear samples obtained on Schirmer strips. There was no correlation between the amount of MUC5AC and age or gender in the healthy population. Dry eye disease patients, however, typically showed reduced concentrations of soluble MUC5AC in the tear film.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Purpose.To determine the effectiveness of prophylactic fluoroquinolone treatment against staphylococci in a rabbit keratitis model.Methods.Prophylactic ciprofloxacin or ofloxacin was applied as one topical drop 15 minutes before infection or as one drop at three time points (19, 17, and 15 minutes) before infection. In a second experiment, rabbits were treated with two, three, or four drops of ciprofloxacin 1 hour before infection. Approximately 250 colony-forming units (CFUs) ofStaphylococcus aureuswere injected intrastromally, and CFUs were determined 5 hours after infection.Results.The CFUs per cornea in all treatment groups were significantly less than the 5.6 ± 0.11 log CFUs per cornea in the untreated group (p≤ 0.0001). Rabbit eyes treated 15 minutes before infection with Ciloxan or Ocuflox had 0.96 ± 0.48 log CFUs per cornea (three of six sterile corneas) or 1.26 ± 0.31 log CFUs per cornea (one of six sterile corneas), respectively (p= 0.5226). Eyes treated with Ciloxan 19, 17, and 15 minutes before infection had 0.0 ± 0.0 log CFUs per cornea, and all eyes were sterile, whereas eyes treated with Ocuflox had 0.98 ± 0.48 log CFUs per cornea and two of six eyes sterile (p= 0.0435). Eyes treated 1 hour before infection with two, three, or four drops of Ciloxan had 2.61 ± 0.69 log CFUs, 1.23 ± 0.32 log CFUs, or 0.85 ± 0.28 log CFUs per cornea, respectively, which was significantly less than untreated eyes (p≤ 0.0001).Conclusions.Multiple topical drops of a fluoroquinolone administered prophylactically were effective for subsequent staphylococcal ocular infection.

ISSN:0277-3740    

出版商:OVID    

年代:2001

数据来源: OVID