Catastrophic manifestation of the antiphospholipid syndrome.

We describe a young woman who displayed the "malignant" variant of the antiphospholipid syndrome (APS), also known as the "catastrophic APS." Renal insufficiency, retinopathy, cerebral infarcts, bone marrow necrosis, skin ulcers, and nasal septum perforation were the result of widespread thrombotic microangiopathy. She recovered during high intensity anticoagulation.

Corneal epithelial permeability during extended wear of disposable contact lenses versus daily wear of soft contact lenses.

AIMS: The corneal epithelial permeability during extended wear of disposable contact lenses was compared with that during daily wear of soft contact lenses. The study was performed to verify whether the extended wear of disposable contact lenses would result in a higher permeability value than the daily wear of soft contact lenses. A higher permeability makes the cornea more vulnerable for bacterial infections and thus could explain the higher incidence of bacterial keratitis found in extended wear of disposable contact lenses in comparison with the daily wear of soft contact lenses. METHOD: The corneal epithelial permeability was determined by fluorophotometry in 33 healthy volunteers after the wear of soft, daily wear contact lenses for at least 6 months. Thereafter the determination was repeated in each volunteer after extended wear of disposable contact lenses for 1 month. The permeability in 34 healthy non-contact lens wearing volunteers was determined as a control. The permeability value was calculated from the amount of fluorescein that passed into the cornea after application by means of an eyebath. RESULTS: The mean permeability values after daily and extended wear were 0.032 nm/s and 0.031 nm/s, respectively. The values were not significantly different (Wilcoxon paired test p > 0.5). The mean permeability for the non-contact lens wearing controls was 0.042 nm/s. CONCLUSION: The results do not sustain the explanation that a difference in permeability value is the main cause of the increased incidence of keratitis during extended wear of disposable contact lenses in comparison with daily wear.

The blue-green autofluorescence of the human ocular lens after the wear of PMMA contact lenses.

The green ocular lens autofluorescence was determined in 30 Poly Methyl Meth Acrylate (PMMA) contact lens wearing volunteers and compared to that of 21 healthy non-contact lens wearing controls to determine whether a contact lens, reducing UV-A intensity reaching the eye, might protect the ocular lens against cataract formation. Increased autofluorescence was considered an indicator of increased probability for cataract formation. A multiple regression procedure revealed a significant yearly increase of autofluorescence with age (p < 0.01) which did not differ significantly (p > 0.86) from that in the controls. The regression procedure also revealed a decrease of the autofluorescence as a function of contact lens wear, but this decrease was not significant (p = 0.3). The order of magnitude of the decrease (-25%) corresponded to that of the calculated decrease in UV-A intensity at the ocular lens (-39%). This study could not support the thesis that cataract formation can be prevented by wearing PMMA contact lenses.

Contact lens care solutions and corneal epithelial barrier function: a fluorophotometric study.

The aim of the study was to evaluate the effect of residual concentrations of two contact lens care solutions (hydrogen peroxide and polyaminopropyl biguanide) on corneal barrier function in vivo. The barrier function was determined by fluorophotometric measurement of corneal epithelial permeability in 30 contact lens wearing healthy subjects after 1 month's use of each of the solutions. All participants except one had corneal epithelial permeability values within the range for non-contact lens wearing healthy volunteers (0.011-0.061 and 0.008-0.090 nm/s, respectively). The deviating value (0.14 nm/s) was due to improper use of the contact lens care system. No statistical significant difference between the permeability values after use of the two contact lens care solutions was found (Wilcoxon ranked paired test: p = 0.2). It can be concluded that both solutions do not have harmful effects on corneal epithelial barrier function, provided the handling instructions are followed.

The effect of white light and UV-A on the green autofluorescence of the rabbit lens in vivo.

The part of the light spectrum which is responsible for an increase of lenticular green autofluorescence upon white light exposure was determined for the rabbit. The increase of autofluorescence as a function of the light energy was measured, to assess a possible threshold energy for lens alterations. Thirteen rabbits (Chinchilla Greys) were used. An area of 3 or 4.7 mm2 of the lens was exposed to light from a standard tungsten halogen lamp (250 W, lambda = 360-720 nm). Wavelength selection was performed with the use of light filters. The light dose was adjusted by varying the exposure time between 15 min and 180 min. The green lenticular autofluorescence (lambda exc = 420-490 nm, lambda fluor = 530-600 nm) was measured with a fluorophotometer. A significant increase of lenticular autofluorescence after exposure was observed only if the exposure light contained high wavelength UV-A (lambda = 360-400 nm; 0.8% of the total white light energy); additional white light (without UV-A; up to 13 kJ cm-2) did not have any effect on autofluorescence. The autofluorescence returned to pre-exposure values within 4 days. No lesions could be seen on slitlamp examination. The autofluorescence after exposure to UV-A increased linearly with the exposure energy from 13 J cm-2 (14 mW cm-2 for 15 min) up to 155 J cm-2. The increase was 2.0% of the pre-exposure value per J cm-2 and the correlation coefficient 0.94, P < 0.001. A threshold energy was not found.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluorophotometric assessment of tear turnover under rigid contact lenses.

To examine the effect of rigid contact lens design on tear turnover the left and right eyes of 25 healthy volunteers were randomly fitted with either a spherical or an aspherical contact lens. Tear turnover is defined as the percentage of decrease of fluorescein concentration in the tear film per minute as a result of tear flow after instillation of fluorescein and can be determined with a fluorophotometer. A drop of fluorescein (1 microliter, 2%) was instilled in each contact lens-wearing eye, whereafter the decrease of the fluorescein was measured for about 30 min. The test was repeated without contact lenses. No statistically significant difference was found between the tear turnover in the spherical, the aspherical, and the non-contact lens-wearing eyes (mean values +/- SD: 15.2 +/- 4.9, 15.6 +/- 5.9, and 16.9 +/- 6.8%/min, p > 0.20).

Corneal epithelial permeability and daily contact lens wear as determined by fluorophotometry.

The condition of the corneal epithelium of 57 non-, 18 soft-, 29 gas-permeable- and 26 hard contact lens-wearing eyes was investigated by fluorophotometric determination of the corneal epithelial permeability. The mean permeability values for non-, soft-, gas-permeable- and hard contact lens-wearing eyes were 0.040 nm/s +/- 0.017 SD, 0.024 nm/s +/- 0.009 SD, 0.028 nm/s +/- 0.017 SD and 0.044 nm/s +/- 0.020 SD, respectively. The mean permeability values for soft and gas-permeable contact lens-wearing eyes were significantly lower than that for non contact lens-wearing eyes (-40%, p less than 0.001 and -30%, p less than 0.005); no significant difference was found between the mean values for hard and non contact lens-wearing eyes (p = 0.38).