[Contact lens care and maintenance]. / Surveillance, hygiène et entretien des lentilles de contact.

All contact lenses with replacement schedules longer than daily must be maintained. At each step of their use, the lenses may be contaminated. Contact lens solutions perform the essential functions of cleaning, decontaminating and preserving the lenses to prevent infectious problems and improve wearing comfort. Contact lens contamination essentially comes from hands, cleaning solutions, cases, water and the environment. The pathogenic microorganisms are mainly Gram-negative bacteria, fungi and amoebae. Contact lens deposits may or may not have an organic origin. Their presence increases the risk of infection because they serve as a nutrient matrix for microbes, and they are responsible for wearing discomfort. Contact lens solutions differ in their composition, their mechanism of action and the concentration of the various agents. To prescribe the best lens care system to each wearer and for each material, it is necessary to be very familiar with them. Maintenance is the main cause of discomfort with contact lenses, either through improper use, solution-material incompatibility, or a reaction of the wearer to the components.

[Role of acute normovolemic hemodilution in treating retinal venous occlusions]. / Place de l'hémodilution aiguë normovolémique dans le traitement des occlusions veineuses rétiniennes.

The supposed state of retinal venous occlusions by a thrombus has led to the use of diverse antithrombotic treatments (heparin, fibrinolytic agents). This theory being considered at the moment as controversial, haemorheological theories being more particularly favoured, other treatments are proposed in an attempt to better retinal microcirculation, and this by changing the blood viscosity parameters. The study reported here compared the effects on recovery of visual acuity of retinal venous occlusion patients of anticoagulant treatment alone, haemodilution alone, or both together. After initial ophthalmic assessment, twenty-five patients were randomly assigned to one of three groups: group I (n = 5; mean age 62 +/- 14 yr) received heparin for 21 days, followed by antivitamin K drugs for a further 30 days; group II (n = 10; mean age 54 +/- 16 yr) were acutely hemodiluted with 40,000 daltons molecular weight dextran, bringing the haematocrit to between 0.25 and 0.30; on day 2, the same anticoagulant treatment as in group I was associated; group III (n = 10; mean age 58 +/- 18 yr) were only hemodiluted. The hemodiluted state was maintained for 21 days. A biological assessment was carried out for the three groups on days 1, 2, 7, 14, 21 and 30 (haematocrit, fibrinogen level, platelet count, kaolin-cephalin time, heparin level). The evolution of visual acuity was assessed on days 7, 14, 21, 30, 60 and 90. Mean visual acuity was assessed on days 7, 14, 21, 30, 60 and 90. Mean visual acuity was virtually the same for the three groups on day 0.(ABSTRACT TRUNCATED AT 250 WORDS)