Home About us Contact
|
Home About us Contact | ||
|
|
||
Endothelial Cell Density (endothelial + cell_density)
Selected AbstractsDescemet's stripping automated endothelial keratoplasty and penetrating keratoplasty for Fuchs' endothelial dystrophyACTA OPHTHALMOLOGICA, Issue 3 2009Jesper Hjortdal Abstract. Purpose:, To compare the outcome of Descemet's stripping endothelial keratoplasty (DSAEK) to that of penetrating keratoplasty (PK) in patients with Fuchs' endothelial dystrophy. Methods:, The first 20 patients who underwent DSAEK at the Department of Ophthalmology, Aarhus University Hospital were compared to 20 patients treated with classic PK. Best-corrected visual acuity, subjective spectacle refraction and corneal thickness were registered before surgery and 1, 3, 6 and 12 months after DSAEK surgery; they were also measured before surgery and 12 months and 2,3 years after PK. Endothelial cell density was measured 12 months after surgery in both groups. Results:, Two primary graft failures were observed in the DSAEK group; no failures were seen in the PK group. Best spectacle-corrected visual acuity (BSCVA) at 12 months after surgery was significantly better in the DSAEK group (0.56 ± 0.04) than in the PK group (0.33 ± 0.06). At this time, 70% of the DSAEK-treated eyes but only 25% of PK-treated eyes had obtained a BSCVA of 0.5 or better. Two to three years after surgery, BSCVA was 0.5 or better in 55% of PK-treated eyes. Refractive ametropia and astigmatism were significantly smaller in DSAEK-treated eyes than in PK-treated eyes, even after suture removal and arcuate keratotomy. Endothelial cell density (cells/mm2) after 1 year was lower in DSAEK-treated (1.338 ± 113) than in PK-treated eyes (1.610 ± 124), but the difference was not statistically significant. Conclusion:, DSAEK seems to be superior to PK in treating Fuchs' endothelial keratoplasty, although primary graft failure may be more common. Visual recovery is faster, and major ametropia and astigmatism is not induced. Long-term follow-up studies are essential to assess whether this conclusion also holds true more than 1 year after surgery. [source] Grafting of the posterior cornea.ACTA OPHTHALMOLOGICA, Issue 5 2000Description of a new technique with 12-month clinical results ABSTRACT. Purpose: To describe the technique of grafting only the posterior cornea and to report 12-month clinical results. Method: A two-layer technique with an anterior recipient flap created by a microkeratome and a posterior penetrating donor graft allows for a watertight wound closure and at the same time a peroperative correction of astigmatism. Four eyes (3 patients) were followed for 12 months. Results: The surgical technique could be completed in all cases without complications. The postoperative course was uneventful. The intrastromal absorbable sutures disappeared spontaneously and completely. Graft thickness showed the expected 6-month minimum while recipient flap thickness remained constant. After 1 year endothelial cell densities were 1200,2300 cells/mm2. Confocal microscopy showed activated keratocytes in the flap and quiescent keratocytes in the donor tissue by one year. The anterior chamber depth was normal in all cases. The optical quality of the cornea was studied by automatic keratometry and keratoscopy (TMS). The obtained optical properties were not optimal. Conclusions: The developed novel technique gives a better wound closure and a complication free postoperative course. It may allow for better control of postoperative astigmatism. In order to disseminate the use of the technique, eyebanks should supply posterior corneas to the surgeon. [source] Absence of corneal endothelium injury in non-human primates treated with and without ophthalmologic drugs and exposed to 2.8,GHz pulsed microwaves,,BIOELECTROMAGNETICS, Issue 4 2010Shin-Tsu Lu Abstract Microwave-induced corneal endothelial damage was reported to have a low threshold (2.6,W/kg), and vasoactive ophthalmologic medications lowered the threshold by a factor of 10,0.26,W/kg. In an attempt to confirm these observations, four adult male Rhesus monkeys (Macaca mulatta) under propofol anesthesia were exposed to pulsed microwaves in the far field of a 2.8,GHz signal (1.43,±,0.06,µs pulse width, 34,Hz pulse repetition frequency, 13.0,mW/cm2 spatial and temporal average, and 464,W/cm2 spatial and temporal peak (291,W/cm2 square wave equivalent) power densities). Corneal-specific absorption rate was 5.07,W/kg (0.39,W/kg/mW/cm2). The exposure resulted in a 1.0,1.2,°C increase in eyelid temperature. In Experiment I, exposures were 4,h/day, 3 days/week for 3 weeks (nine exposures and 36,h total). In Experiment II, these subjects were pretreated with 0.5% Timolol maleate and 0.005% Xalatan® followed by 3 or 7 4-h pulsed microwave exposures. Under ketamine,xylazine anesthesia, a non-contact specular microscope was used to obtain corneal endothelium images, corneal endothelial cell density, and pachymetry at the center and four peripheral areas of the cornea. Ophthalmologic measurements were done before and 7, 30, 90, and 180 days after exposures. Pulsed microwave exposure did not cause alterations in corneal endothelial cell density and corneal thickness with or without ophthalmologic drugs. Therefore, previously reported changes in the cornea exposed to pulsed microwaves were not confirmed at exposure levels that are more than an order of magnitude higher. Bioelectromagnetics 31:324,333, 2010. Published 2010 Wiley-Liss, Inc. [source] 3234: Stability of corneal shape and morphology in patients with Fuchs' dystrophy after phacoemulsification with soft shell technique.ACTA OPHTHALMOLOGICA, Issue 2010M MILKA Purpose To evaluate effectiveness of soft shell cataract surgery technique on the corneal structure in group of Fuchs' dystrophy patients. Methods 24 patients (mean age 52,7±13,8), 31 eyes after phacoemulsification were examined before and 10 months after surgery. BCVA, mean central corneal thickness (CCT) and corneal endothelial cell density (CD) were evaluated. Corneal aberrations root-mean-square (RMS) was calculated 1 and 10 months after surgery for 4.0mm pupil. Results Corneal higher-order aberrations (RMS) 1 month after surgery was 0,372±0,058 and 10 months after surgery was 0,345±0,076, BCVA 10 months after surgery was 0,75±0,27 (before surgery 0,32±0,28), the mean CCT was 563,37±21,42µm (before surgery 559,62±45,29µm), CD 1786,341±493,127 (before surgery 1912,783±381,963). Conclusion All patients revealed good stability and protection of the cornea confirming safety of the soft shell technique. [source] 4332: Determination of corneal endothelial cell density in French eye banks: second lookACTA OPHTHALMOLOGICA, Issue 2010N DELESALLE Purpose Considering the importance of having a precise, robust and especially reproducible ECD counting method, Afssaps organized from April 2008 to June 2009 a second assessment of the reliability of the routine cell count within the 18 french Eye banks. Methods The study design was similar to the first assessment driven by the laboratory ,Biology, engineering and imaging of Corneal Graft' in 2003 (Transplantation 2004; 78: 1299-1302).5 test corneas (1 mm2 of flat mounted, fixed and alizarin stained human corneal endothelium) were selected and sent to the 18 Eye banks. All the usual technicians of each bank had to count the test corneas using the routine method(s) employed to assess grafts. Results 430 counts were carried out by 70 eye banks technicians, by manual and/or image analysis system. 42% (180/430) deviated by more than 10% from the expected ECD. Among them, 128 were over-estimated (max +88%) and 52 were under-estimated (max -31%). 2 banks constantly over-estimated (in the mean +31,7% and +42,7%, no calibration and/or material problem) but the 16 other banks were in average within ±13% from expected ECDs. For manual methods, a statistically significant difference between banks was observed for the 5 test corneas, whereas no difference was observed with image analyzers. ECD obtained with the analysers were closer to expected values than with the manual methods. Compared to the 2003 study, reliability of ECD determination globally improved. Conclusion Image analysis systems prove more reliable (precise and with a lower intra and inter observer variability) than manual counting methods. This ,second look' of Eye banks will allow editing recommendations to improve ECD determination. [source] Re-examination of organ-cultured, cryopreserved human corneal grafts after 27 yearsACTA OPHTHALMOLOGICA, Issue 2 2009Charlotte Corydon Abstract. Purpose:, To determine the long-term fate of cryopreserved corneas. Review of 17 organ-cultered cryopreserved corneas grafted in 1978,1979. Methods:, We measured visual acuity and refraction and performed biomicroscopy, applanation tonometry and optical pachometri (CCT). Endothelial photos were taken, cells were counted and morphology was studied. Results:, Four of 16 grafted corneas were still clear after 27 years. Mean CCT was 0.52 mm, endothelial cell density was 882 cells/mm2 and visual acuity was 0.25 or better with an average of 0.6 in the four patients. Cell morphology showed irregularity in shape and size. Conclusion:, This study shows that cryopreserved endothelium can function as well as non-frozen corneas and that a regular hexagonal pattern is not essential for corneal clarity. The four grafts showed long-term durability despite the irregularity in shape and size. [source] Could the coefficient of variation (COV) of the corneal endothelium be overestimated when a centre-dot method is used?CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 1 2008Michael J Doughty PhD Background:, Little has been published on the reliability of estimates of the coefficient of variation (COV) in cell area for human corneal endothelia. The present study compares two methods. Methods:, A non-contact specular micrograph (Topcon SP-2000P) was obtained from the central region of the corneal endothelium of 20 healthy myopic white European subjects, aged from 32 to 53 years, half of whom were successful long-term soft contact lens wearers. The captured image file was either assessed using a machine-based algorithm, in which 25 cells in the middle of the image were marked and their areas reported (designated as ,centre-dot' method) or by a manual method, by which all the cells in the image were outlined on very high magnification prints of the endothelia and the cell areas measured by a manual digitiser in stream mode. The average cell area was used to calculate the endothelial cell density (ECD), while the COV was calculated from the standard deviation (SD) of the cell area measures. Results:, Identical mean cell area values were found (392 µm2) with the two methods, a marginally higher ECD estimate (2,594 versus 2,569) with the centre-dot method (p = NS) but a much higher COV with the centre-dot method (43.8 versus 29.0 per cent). This highly statistically significant difference in COV (p < 0.001) was seen in both contact lens wearers and non-contact lens wearers. A Bland-Altman analysis reveals a bias in the centre-dot method, especially for the COV estimates, that appears to be linked to erroneous definition of a single large cell domain on any individual image. Conclusions:, A centre-dot method can be reliably used to generate useful data on cell area and ECD but it should be used cautiously for estimates of polymegethism (COV). [source] | ||||||||||