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)

In 1984, I reported that the refraction constant used in the SRK formula was too high and should have a value of 1.0 or less. The term refraction factor (RF) was adopted to replace the refraction constant which was under scrutiny. The current study was done in four phases. Phase 1 showed improved refraction prediction accuracy for sulcus-fixated intraocular lenses (IOLs) when an RF of less than or equal to 1.0 was used instead of a fixed RF of 1.25. The anterior chamber IOLs had worse results under the same conditions. Phase 2 retrospectively determined computer optimized and matched A constant and RF pairs for anterior chamber, sulcus-fixated, and bag-fixated IOLs for all axial lengths (AL), short (AL less than or equal to 21.5 mm), long (AL greater than or equal to 24.5 mm), and mid-range (21.5 mm less than AL less than 24.5 mm). Phase 3 demonstrated a dramatic improvement in the refraction prediction accuracy when the matched pairs according to AL were used in 61 consecutive patients receiving Jaffe, bag-fixated IOLs. Phase 4 demonstrated good results in 15 consecutive patients, using the RF found for Jaffe IOLs in calculations for a meniscus-type, bag-fixated IOL, with which I had no experience. I determined that the longer the eye, the smaller the RF, for any given IOL position in the eye. The data indicated that different RFs should be used for different IOL locations within the eye. The more forward the IOL, the larger the RF.(ABSTRACT TRUNCATED AT 250 WORDS)
J Cataract Refract Surg 1989 Sep
PMID:Using the intraocular lens refraction factor to improve refractive prediction accuracy. 232 91

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

Accurate intraocular lens power calculation is an important adjunct to the technique of extracapsular cataract extraction. An increasing number of ophthalmologists now perform preoperative biometry routinely. We studied a group of fifty patients and analysed the accuracy of intraocular lens power calculation using the SRK formula.
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PMID:Intraocular lens power calculation. 325 28

Intraocular lens power prediction and final astigmatism were evaluated in 100 consecutive cataract patients (age 57-92 years, mainly with intracapsular extraction) 4-13 months after insertion of a 3M type 78 anterior chamber lens. The analysis was based on refractive recordings from the referring ophthalmologists who took care of post-operative controls. Ninety-two patients were accepted for the study. A Sonometrics DBR 400 ultrasound equipment and a Haag-Streit keratometer had been used for measuring eye length and corneal power, the Binkhorst programme and SRK formula for selecting IOL power, resulting in an IOL range of +12 to +23 D. Mainly, low myopia was intended. Nearly 50% fell within 0.5 D from predicted value; 90% were within +/- 1.5 D, by both calculating methods. SRK predictions appeared unaffected by eye size, while axial length (x) significantly influenced Binkhorst prediction (y): y = 8.08-0.35x (r = -0.40), the deviation being most marked in very short eyes. For eyes of midsize the two methods did not differ. Regarding astigmatism, 3 patients ended with values above 3D. In 83% it was less than 2D. Eighty per cent obtained a visual acuity of 0.5 or better. All things considered we feel that the calculation procedure should be standard when performing cataract surgery with IOL implantation.
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PMID:Intraocular lens calculation. An evaluation of Binkhorst and SRK estimates in 100 consecutive cataract extractions with 3M type 78 anterior chamber lens implantation. 332 76

A simple modification of the SRK formula was developed for use with extreme axial length cases (short and long eyes) to maximize prediction accuracy in these groups. For "average" eyes (over 75% of all cases), SRK needed no modifications to maintain maximum predictive accuracy. The new, modified SRK formula (SRK II) was compared with current second generation formulas and the Binkhorst formula. The SRK II formula, while maintaining the simplicity and ease of the SRK, was comparable to and in some cases superior to the other formulas. Overall, 80.0% of 2,068 posterior chamber intraocular lenses from seven different manufacturers demonstrated less than one diopter of prediction error and only 0.5% had three or more diopters of error. In short eyes (less than 22 mm), 74.0% were corrected to within one diopter and less than 2.0% had three or more diopters of error. In long eyes (greater than or equal to 24.5 mm), 78.0% of cases demonstrated less than one diopter of error and less than 1.0% had three or more diopters of error. Although the SRK II formula is incorporated in most new A-scan units, the modifications are so simple that surgeons can take the standard SRK predictions and mentally calculate the modifications for extreme cases.
J Cataract Refract Surg 1988 Mar
PMID:Comparison of the SRK II formula and other second generation formulas. 335 49

We evaluated aphakia and pseudophakia in highly myopic patients whose axial lengths were 27 mm and over. Cataract surgery alone was performed on 99 eyes (aphakic group) and intraocular lens (IOL) implantation was performed on 84 eyes (pseudophakic group). The IOL power was determined by the SRK formula and ranged from +9.0 to +18.5 diopters (D). There was no statistical difference in postoperative complications between the aphakic and pseudophakic groups. The postoperative aphakic refractions ranged from +9.5 D to -3.5 D, and the pseudophakic refractions, from +2.5 D to -14.0 D. A visual acuity of 20/40 or better was achieved by 51% of aphakic patients and 63% of pseudophakic patients. A near visual acuity of 20/40 or better was achieved by 65% of pseudophakic patients. Seventy-three pseudophakic eyes (87%) were not corrected or were corrected with minus diopter lenses. This confirmed our opinion that there was no need to correct them for near vision. According to a postoperative questionnaire, 67% of the pseudophakic patients did not need spectacles for near vision and 93% of patients could see comfortably for daily life. In view of these results, we feel that most myopic patients are good candidates for IOL implantation.
J Cataract Refract Surg 1988 Jul
PMID:Intraocular lens implantation and high myopia. 340 24

The postoperative refraction prediction was evaluated in 99 patients with a 19.0-diopter standard power anterior chamber lens using a theoretical, computer-assisted method based on Gaussian optics and an empirical intraocular lens calculation method based on the SRK formula. Both the theoretical and the empirical predictions accorded with the observed values in the near emmetropia region. In the prediction of ametropia, the SRK method showed a tendency to predict refractions that were lower than the actual values in hyperopic eyes and higher than the actual values in myopic eyes. The bias of the SRK method may be due to the use of an erroneous refraction factor that converts the ametropia to the deviation in implant power from the emmetropia power. By introducing an individual refraction factor, the accuracy of the SRK method approached that of the theoretical method.
J Cataract Refract Surg 1987 Mar
PMID:Theoretical, computer-assisted prediction versus SRK prediction of postoperative refraction after intraocular lens implantation. 357 70

Several different formulas are available for preoperative calculation of the required implant power for a desired postoperative refraction. However, the application of both theoretical and statistically derived regression formulas to the new generation of soft intraocular lens implants poses several difficulties. In this paper the calculation of an A constant for a specific intraocular hydrogel lens implant, as well as the derivation of a universal theoretical formula, is described. The theoretical formula can be applied to other implant styles with various optical configurations and composed of different biomaterials. The SRK and theoretical formulas have been applied retrospectively to a series of patients receiving an intraocular hydrogel lens implant. A comparison shows that both perform satisfactorily in predicting the desired postoperative refraction.
J Cataract Refract Surg 1987 Jul
PMID:Intraocular lens calculation formulas for new intraocular lens implants. 362 16

The aphakic refraction was predicted from preoperative and postoperative keratometry and axial length determinations in 43 patients subjected to cataract extraction without intraocular lens implantation using a theoretical and an empirical (Sanders, Retzlaff, Kraff [SRK]) method of calculation. The error (mean +/- SD; observed value minus expected value) of the theoretical vs the empirical method was 0.02 +/- 0.76 diopters (D) vs 0.66 +/- 0.72 D, respectively, when the preoperative data were used in the calculations, and 0.21 +/- 0.80 D vs 0.84 +/- 0.79 D, respectively, when the postoperative data were used in the calculations. The mean error was significantly different from zero (predicted values were lower than observed values) for the SRK method but not for the theoretical method. The mean error of the SRK method could be eliminated by adjusting the offset constant in the regression formula.
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PMID:Theoretical vs empirical prediction of aphakic refraction. 363 11

Sixty-seven patients were examined 3 to 5 1/2 (mean 4) months after intended extracapsular cataract extraction with implantation of the 3 M, style 83, posterior chamber lens. A visual acuity greater than or equal to 0.5 was recorded in 58 (86.6%) of the patients. The complications were: one (1.5%) case of acute iritis, one case of pupillary capture and two (3.0%) cases of capsulotomy-requiring early secondary cataract. There were no posterior segment complications. None of the patients were treated with anti-glaucomatous medication, and none had intraocular pressure above 20 mmHg. Pre-operatively, biometry was performed, and the SRK-formula was employed in estimating the post-operative spherical equivalent refraction: The actually measured refraction differed less than 2 diopters from the predicted refraction in 84.5% of the cases.
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PMID:Complications and visual outcome 4 months after extracapsular cataract extraction with implantation of posterior chamber lenses. A prospective clinical study. 381 64


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