PubMed · 7342864
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A Bronner, J F Dreyfuss. 1980. [Automatic refraction].. https://pubmed.ncbi.nlm.nih.gov/7342864/
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BACKGROUND: In the management of congenital cataracts the correction of aphakia is still an unsatisfactorily solved problem. As far as surgical techniques and materials are concerned, the implantation of an IOL seems to be justified even in younger children; but choosing the refractive power of the lens is somewhat difficult regarding the expected growth of the eye. MATERIALS AND METHODS: A new type of IOL is presented as a solution for this problem. Being composed of a PMMA-fashioned optic and haptic it bears a silicone lens which is fastened on top of it. The supporting lens is made of PMMA (polymethylmethacrylate) with a biconvex surface with modified J-loops. The diameter of the optic is 6 mm, the overall diameter is 11 mm. The supplementary lens is made of the same silicone material as used for foldable intraocular lenses. Its diameter is 4.5 mm. This additional component can be removed from the implanted lens so that the needed reduction of refractive power after completed growth of the eye can be performed. The PMMA-fashioned basic component remains in situ just like a conventional posterior chamber lens. The lens was examined using scanning-electron microscopy. Im- and explantation was performed in isolated porcine eyes. RESULTS: The high quality of the lens could be demonstrated using scanning-electron microscopy. The technical feasibility of this concept could be demonstrated on isolated porcine eyes. DISCUSSION: Currently the sandwich lens is being tested in animal experiments. Our special interest is focussed on biocompatibility, formation of secondary cataract, biological reactions in the interface and the possibility of atraumatic explantation of the silicone lens.
OBJECTIVE: To describe the pattern reversal visual evoked potentials (VEPs) that were used to monitor and quantify early visual development following treatment for dense, unilateral, congenital cataract. DESIGN: Longitudinal prospective study. PATIENTS: Six infants who underwent surgery and contact lens correction before age 5 months and who had good compliance with occlusion therapy throughout the first 3 years of life. RESULTS: Initially, VEPs from aphakic eyes showed marked abnormalities, including small amplitudes, prolonged latencies, missing components, and absent VEPs to small check sizes. Threshold check size was elevated by 3 octaves or more. With part-time occlusion of the opposite eye, VEPs normalized rapidly in the first year, but residual deficits remained to age 4 years when visual acuities were between 20/50 and 20/120 in aphakic eyes. Threshold check size clearly differentiated between aphakic and normal eyes and was the only VEP parameter that was correlated with single-letter visual acuity. Thus, threshold check size had greater clinical use than measures of pattern VEPs based on latency, amplitude, or waveform. CONCLUSIONS: Patients treated for unilateral congenital cataract, who have early surgery and contact lens correction and comply with occlusion therapy, show a period of rapid VEP maturation and have a good visual prognosis.