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Biomedical subjects

J Boberg-Ans

Publications and source records attributed to J Boberg-Ans.

17 recordsLinked to original sources
PubMed1990

Biometry of the posterior lens capsule: a new method to predict pseudophakic anterior chamber depth.

The distance between the anterior corneal vertex and the posterior lens capsule was measured in 60 eyes before and three months after extracapsular cataract extraction with implantation of a posterior chamber lens. The preoperative capsule position ranged from 6.15 mm to 8.60 mm and averaged 7.64 +/- 0.47 mm (+/- SD). All posterior lens capsules had moved anteriorly following surgery. The postoperative capsule position ranged from 4.31 mm to 5.53 mm and averaged 4.93 +/- 0.29 mm. The postoperative capsule position could be predicted by the following optimized multiple linear regression equation: 2.4 + 0.011 x patient age + 0.171 x anterior chamber depth + 0.051 x axial length. The multiple correlation coefficient was 0.48. The postoperative anterior depth could be predicted with a correlation coefficient of 0.61 by subtracting both the averaged value of the clinical "laser space" and the exact central implant thickness from the estimated position of the posterior lens capsule. We suggest that this principle for predicting the postoperative anterior chamber depth may be useful for a number of lenses with different designs.

Adult↗
PubMed1989

Axial length following implantation of posterior chamber lenses.

We used ultrasound to measure axial length in 66 eyes before and three months after extracapsular cataract extraction with implantation of a posterior chamber lens. An ultrasound velocity of 2,718 m/s for poly(methyl methacrylate) was assumed. The intraindividually measured difference (postoperative--preoperative axial length) ranged from -0.4 mm to 0.6 mm and averaged 0.11 mm. The lengthening of the eye was statistically significant (P less than .001; two-tailed, paired t-test). Statistical analysis of the regression equation between the preoperative and the postoperative axial lengths disclosed that this correlation was not more accurate than simply substituting the two measurements. Assuming no real change in axial lengths, our data suggest an ultrasound velocity of 1,679 m/s for the natural lens or an average velocity of 1,560 m/s for the phakic eye. We conclude that the preoperatively measured axial length may be used as a fairly accurate estimate of the postoperative distance in intraocular lens power calculation formulas.

Biometry↗
PubMed1988

Prediction of pseudo-phakic anterior chamber depth from pre-operative data.

Multiple linear regression analysis of pre-operative data were used to construct formulas to predict the anterior chamber depth 3 months after implantation of two different posterior chamber lenses. The resulting formulas differed widely. For lens I (27 eyes) the formula had a correlation coefficient of 0.78 and a standard deviation of +/- 0.2 mm. The corresponding figures for lens II (41 eyes) were 0.52 and +/- 27 mm. For lens I the predictors of significance were axial length (P less than 0.0001) and anterior corneal curvature (P = 0.07). For lens II significant predictors were patient age (P = 0.0008) and pre-operative anterior chamber depth (P = 0.04). We suggest that post-operative anterior chamber depth may not solely depend on the dimensions of the eye, but also on the lens architecture and the 'memory' of the lens haptics. We conclude that formulas to predict post-operative anterior chamber depth should be derived empirically for each lens type separately.

Age Factors↗
PubMed1977

Differences and similarities in a series of cases with bilateral intraocular lenses and evaluation of the results.

A review is given of the results of intraocular lens implantation in 38 patients, that is, 76 eyes. The observation time was up to 7 1/2 years. Only 5 cases were done as a secondary procedure. The Binkhorst 4-loop lens was preferred. Most of the lenses were fixated with an iris-lens suture. Out of 8 lens luxations 2 were fixed with an iris suture. The final visual acuity and the difference in refraction in spherical as well as cylindrical power are surveyed. The astigmatism and the astigmatic axis are compared in the 2 eyes of each patient. Most of the patients regained stereoscopic vision. It is concluded that neither the lens position, the lens type, the number of iris sutures, nor the number of iridectomies had any influence on the eventual results.

Adolescent↗