Biomedical subjects
Publications and source records attributed to C D Binkhorst.
The treatment of lens injury in children with irido-capsula supported intraocular lenses is described. A consecutive series of 73 children is analyzed as to the functional results and complications. Surgery and anaesthesia are discussed in detail. Guidelines are given for future straightforward management of eye injury in children, using this promising possibility of visual rehabilitation.
The implantation of an iseikonic prepupillary intraocular lens in unilateral aphakia usually requires a slight (2 D) myopia of the implanted eye if the two eyes are isometropic. On the other hand, the implantation of an iseikonic implant in one eye of a anisometropic (asymmetric) eye pair can result in unexpectedly high changes in spectacle ametropia, due to differences in axial length or corneal power. The changes in ametropia after iseikonic lens implantation are discussed in relation to preoperative corneal and axial anisometropias. Alternative procedures to iseikonic implantation are described.
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Whereas by far not all properties of the crystalline lens can be realized with an artifical intraocular lens, maximal stability of such a device is its most important feature. The latter can be achieved by the adherence of the lens to the capsular membrane, left behind after extra-capsular cataract extraction. In this way the suspension system of the crystalline is used for the fixation of the intra-ocular lens. The stability of the contents of the eye viz. of the vitreous, of the aqueous humour, and of the iris diaphragm, is maintained to a high degree. Stability of the iris diaphragma is achieved when irido-capsulo-lenticular adhesions are allowed to develop, but the iris diaphragm can also be stabilized by support from the optical part of a modified capsular lens in the posterior chamber.
Specular microscopy helps to estimate the viability of the corneal endothelium long before clinical signs of decompensation occur. Therefore, specular microscopy is useful for the selection of eyes for lens implantation in general; for the prognosis of the eye with a lens implant; and for the evaluation of the method of cataract surgery, of lens implantation techniques, and possibly of lens design, material, and manufacturing. A long-term study of intracapsular and extracapsular pseudophakic eyes revealed that the intracapsular pseudophakic eyes had significantly less endothelial cells, which could partly be explained by toxicity of the Supramid used as loop material, but mostly by assuming continuing endothelial disintegration in the intracapsular eyes. In 41 patients our extracapsular technique caused an average cell loss of only 6.7%.
The treatment of lens injury in children with irido-capsular supported intraocular lenses is described. A consecutive series of 73 children is analyzed as to the functional results and complications. Surgery and anesthesia are discussed in detail. Guidelines are given for future straight-forward management of eye injury in children, using this promising possibility of visual rehabilitation.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The principle and technique of Maurice's method of microscopy of the corneal endothelium at high magnificant is discussed. An instrument is now available for clinical use (clinical specular microscope). The experience of the authors in patients with an intraocular lens is reported. A rather high deficit of endothelial cells was found in a series of 26 children and young adults, that had suffered injury from 2 to 11 years previously. An average immediate endothelial cell loss of only 6-7% was found in extracapsular cataract extraction with simultaneous implantation of a 2-loop or 4-loop intraocular lens. A striking difference was found between the two eyes of bilateral pseudophakic patients when one eye had undergone intracapsular surgery and the other eye extracapsular surgery. It had to be concluded that barrier deprivation of the intracapsular aphakic eye leads to continuing endothelial cell loss other than through ageing. Subclinical and clinical late corneal dystrophy therefore belong to the "barrier deprivation syndrome" together with retino-vascular accidents (macular and optic disc oedema) and vitreous degeneration.
I developed my own lens designs after analyzing the reasons for failure of previous designs. The iris clip lens and the capsular lens are supported by the iris and by the capsular membrane, respectively, the former having minimal and the latter having nearly no contact at all with intraocular tissues. A comparison between the iris and capsular membrane as support for an intraocular lens favor the capsular membrane.
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A follow-up of 120 pseudophakic eyes of 85 patients that underwent surgery for senile cataract showed a definite superiority of extracapsular surgery over intracapsular surgery as far as the longterm fate of the retina concerns. Comparable series have been chosen. Retinal detachment did not occur in extracapsular eyes that never had posterior capsulotomy, and occurred most often after intracapsular surgery. Signs of previous or existing maculopathy were searched for with the usual tests (funduscopy, visual acuity, Amsler test) and moreover with Haidinger's brushes test. The macula turned out to have least suffered after extracapsular surgery without capsulotomy and most after intracapsular surgery. Haidinger's brushes test is a valuable tool for the detection of postoperative macular edema.
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