Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Axial length and corneal curvature are entered into formulae to calculate intraocular lens power for cataract surgery and the absolute measurement of fundus structures such as neuroretinal rim area in glaucoma. The reproducibility (coefficient of variation, CV) of biometry and keratometry was investigated by taking five measurements of thirty phakic eyes. Although both techniques were found to be highly reproducible (CV less than 1%), keratometry was the more so. However, a clinically significant difference was noted between the first and the mean of five readings for both biometry (0.15 +/- 0.05 mm) and keratometry (0.05 +/- 0.03). Taken together, these errors would result in a postoperative refractive error of 0.65D using the SRK formula. Measurement errors were just as likely to occur with short or long eyes. Similar results were found when the analysis was performed on three measurements of both axial length and corneal curvatures. We recommend taking the average of three biometry and keratometry readings to improve the reliability of the techniques, and to increase the accuracy of calculating intraocular lens power and fundus structure dimensions.
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PMID:The reproducibility of biometry and keratometry measurements. 180 Jan 71

It was previously reported that the axial length and the refractive error were analyzed in selecting intraocular lens powers which were calculated by the SRK formula. Moreover, the predicted postoperative refraction was compared with the actual postoperative refraction. Two modifications of the SRK formula were derived from these relationships as follows; Modified SRK formula 1: R = 0.98 (P-I)-0.16L + 4.48, Modified SRK formula 2: R = 0.82 (P-I)-0.21L + 5.39. The modifications of the SRK formula were evaluated in 200 other eyes after posterior chamber lens implantation. As a result, the average refractive error was + 0.397 +/- 0.585D by the standard SRK formula, but it decreased by an average numbers of + 0.037 +/- 0.557D and + 0.047 +/- 0.547D respectively by modified SRK formulae 1 and 2. While the incidence of deviation within +/- 1.0D was 87.0% for the standard SRK formula, it was 94. 5% for both modified SRK formulas. The refractive errors, moreover, were less dependent on the axial length with both modified SRK formulae. The predicted postoperative refraction was more accurate by modified SRK formulae, especially between emmetropia and myopia up to 0.5 diopters.
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PMID:[Clinical evaluation of modifications of the SRK formula]. 187 12

Analytical predictions of primary implant power using presumptive errors in keratometer and axial length measurements were performed using the modified Binkhorst, modified Colenbrander, Holladay, Hoffer, and SRK II equations. These predictions demonstrate that the contributions to primary implant power error resulting from inaccurate axial length and keratometer measurements are algebraically additive. In eyes with a normal axial length, the resulting implant power determination error can be larger than differences in implant power prediction among these five IOL equations. Calculations using measurement errors of 0.2 mm in axial length and 0.50 diopter (D) in corneal curvature predicted a worst case primary implant power error of +/- 1.17 D. These calculations were performed using an axial length and corneal curvature near the population mean. In contrast, implant equation variability was determined to be +/- 0.19 D by calculating the standard deviation of the five implant power formulas with the measurement errors set to zero. Implant power prediction errors were increased when a flat cornea was paired with an axial hyperopic or an axial myopic eye. These combinations maximize the implant power error resulting from both implant formula variation and inaccurate measurements. Primary implant power error prediction tables are presented for emmetropic, axial hyperopic, and axial myopic eyes, as a function of presumed errors in axial length and corneal curvature. These error predictions clearly show that inaccuracy in axial length measurements and keratometer readings can be first order determinants of postoperative spherical refractive error.
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PMID:Effect of keratometer and axial length measurement errors on primary implant power calculations. 229 77

Twenty-one consecutive triple procedures (keratoplasty, cataract extraction, lens implantation) performed by one surgeon using identical suturing technique, donor size, and donor/recipient size disparity were analyzed for visual outcome and refractive error. Ninety-five percent of all grafts were clear with an average follow-up of 11.8 months. Of patients with good preoperative visual potential, 84% achieved 20/40 or better visual acuity, and the majority of these patients obtained 20/40 acuity within 6 months of surgery. Sixty-three percent of eyes with 20/40 or better acuity had refractions within +/- 2 diopters of the predicted post-operative refraction. The most recent 14 eyes in this series had IOL power calculations performed utilizing the SRK regression formula and 43.00 K's (surgeon's average post-keratoplasty keratometry values). Within this group, 79% achieved 20/40 or better vision. Eighty-two percent of these eyes had refractions within +/- 2 diopters, and 100% were within +/- 3 diopters of the predicted value. These findings demonstrate that a single surgeon using standardized keratoplasty can achieve good refractive results in the triple procedure.
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PMID:The effect of standardized keratoplasty technique on IOL power calculation for the triple procedure. 255 54

The error in prediction of emmetropic intraocular lens power or postoperative refractive error after lens implantation was analyzed in three groups of eyes after posterior chamber lens implantation. Regression line calculation with the SRK equation or with a group-specific regression was compared with theoretical calculations in unselected, long myopic and short hyperopic eyes. The cut-off length was below 22.0 mm for the short eyes and above 25.9 mm for the long eyes. In the unselected and hyperopic group, there was only a small difference in mean error and error variance when the three calculation methods were compared. In the high myopic group, the range of error increased in all methods. The worst results were obtained with the standard SRK equation because the slope of the regression line in myopic eyes differs from the classical regression line calculated on an average population of implants. Lens calculation in high myopic eyes should therefore be performed with a specific regression line or by theoretical calculation.
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PMID:Effectiveness of intraocular lens calculation in high ametropia. 235 33

Two hundred and two consecutive intraocular lens (IOL) implantations, the lens power being predicted with the SRK-method, are retrospectively analyzed, and the factors possibly influencing the error in IOL power prediction are evaluated. The actual post-operative refraction is compared to the expected refraction for each IOL and to a hypothetical refraction that would have been obtained by a standard-power IOL implant. Axial length measurement and a high pre- and post-operative astigmatic error, along with low- and high power IOL predictions, are the factors that most influence the post-operative refractive error. A similar distribution of post-operative refraction could have been obtained by using a standard-power IOL instead of pre-operative calculation.
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PMID:Intraocular lens power calculation. A retrospective analysis of its practical value. 277 41

A retrospective survey of 612 eyes that had undergone cataract extraction and IOL implantation was undertaken to evaluate the accuracy of ultrasound biometry combined with keratometry using the SRK regression formula, for the preoperative prediction of intraocular lens powers. A mean error of +0.35 dioptre sphere (DS) (SD +/- 0.98) was found for the series overall, with a significant (P less than 0.005) difference between the distribution of postoperative refractive errors using the S.R.K. formula for IOL prediction and the use of a standard lens of 19.5 DS. The consistency of results was tested for those patients with greater or less than normal axial length. Linear regression analysis showed no correlation between axial length and postoperative refractive error and therefore does not support the adjustment of predicted IOL powers by a factor based on axial length. Statistically significant differences were found between surgeons' results, supporting the practice of A-constant modification for individual surgeons.
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PMID:IOL prediction: an evaluation of preoperatively determined intraocular lens power accuracy. 305 21

The refractive results of 43 consecutive triple procedures (transplant, cataract extraction, and lens implant) performed by one surgeon were analyzed. Twenty-one out of 43 eyes achieved refractive errors within 2 diopters (D) of emmetropia. The mean refractive error was -1.79 D, and the mean corneal astigmatic error was 2.75 D. Seventy percent of the eyes achieved 20/40 or better corrected acuity. Forty-four percent had 20/80 or better uncorrected acuity. Using the average postoperative keratometry readings from other recent transplant cases and an updated A constant in the SRK regression formula would have placed 39 of 43 eyes (91%) within 2 D of emmetropia with a mean refractive error of -0.07 D. The use of recent keratometry readings in a multiple regression formula is recommended to improve refractive results with the triple procedure.
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PMID:Intraocular lens powers used in the triple procedure. Effect on visual acuity and refractive error. 390 37

The accuracy of prediction of postoperative refractive error was evaluated in 175 patients with extracapsular cataract extraction and a Shearing-style posterior chamber intraocular lens. The Binkhorst, Colenbrander - Hoffer and SRK formulas were all less accurate in patients with an axial length greater than or equal to 24.5 mm. The standard error of the estimates of the Binkhorst formula was 1.2 diopters, the Colenbrander - Hoffer formula 1.18 diopters and the SRK formula 0.90 diopters. A new intraocular-lens formula for axial myopes was derived by polynomial regression analysis with a standard error of the estimate of 0.85 diopters. This new formula was accurate within 1 diopter in 79% of axial myopes compared to 71% for the SRK , 66% for the Colenbrander - Hoffer and 64% for the Binkhorst formulas. Regression analysis of a surgeon's own patient data can further improve the accuracy of prediction of the post-operative refraction.
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PMID:A new posterior chamber intraocular lens formula for axial myopes. 673 51

The author selected 12 groups of patients (858 patients altogether). The operation was carried out by the same surgeon and the same type of IOL was implanted in each group. An individual A-constant was calculated for each patient. Using individualized A-constant for each group a postoperative refractive error was calculated for each patient. Following formulas were used for the calculation: SRK, SRK II, Holladay formula (A-constant), Holladay formula (surgeon factor) and SRK/T. No substantial difference between the results of formulas SRK, SRK II, Holladay formula (surgeon factor) and SRK/T was found. The postoperative refractive error +/- 1.0 D was found in the interval 65.6% - 67.8% for all these formulas. Holladay formula (A-constant) yielded the postoperative refractive error +/- 1.0 D in 62.2% of cases.
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PMID:[The accuracy of optical power calculations of intraocular lenses in cataract surgery]. 805 Jan 10


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