The prevalence of exfoliation syndrome among Saudis was determined during the National Survey of Blindness and Eye Disease in 1984 in Kingdom of Saudi Arabia. The subsample of this study consists of 376 persons aged 40 years or more from 50 different locations examined under mydriasis by the authors using Kowa hand-held microscope. There were 192 men and 184 women with the mean age of 56.0 f 1.2 years (median 53.5 years, range 40-95 years).The overall prevalence of exfoliation syndrome was 9.3 Yo: in the age group 40 to 49 years 1.6 Yo, 50 to 59 years 7.8 Yo, 60 to 69 years 8.9 Yo, and 26.5 Yo in persons 70 years of age and over. No significant association was found between exfoliation syndrome and sex or parental kinship.In 16 persons the exfoliation syndrome was unilateral, and in 19 persons bilateral. In 24 eyes the phenomenon could not be evaluated due to the anterior segment pathology.Exfoliation syndrome was associated with higher intraocular pressure (20 f 3 mmHg (n = 49) vs. 17 f 0.4 mmHg (n = 601), P < 0.05), and more cataract changes (P < 0.001) than eyes without. These eyes were also associated with poorer visual acuity than the eyes without exfoliation syndrome: in 26 of 35 persons with exfoliation syndrome, the affected eye was the better eye but in 35 Yo the vision was < 0.05 (< 3/60) i.e. the person was blind, compared to 6 Yo of persons whose better eye did not have exfoliation syndrome (P < 0.001).
ABSTRACT.Purpose: In 1992-94 a nation-wide survey in primary schools in the Sultanate of Oman for ocular disorders was conducted. This report focuses on the prevalence of visual acuity loss after injury. Methods and material: A random selection of 6292 children from Grades 1 and 6 from all primary schools in the country provided the research sample. Children who failed the visual acuity screening test received a complete ''on the spot'' eye examination by the pediatric ophthalmologist. Results: 12 children were found to have monocular low vision (VA ∞0.3 to amaurosis) caused by injury. Total prevalence for loss of vision in one eye was 0.19%, with 0.15% in 6-year-olds and 0.25% in 12-year-olds. Traumatic cataracts were noted in 4 children, 3 of these were in need of surgery. One child had aphakia after trauma surgery and needed a secondary lens implant. Conclusion: Altogether the prevalence of traumatic monocular visual damage in our study was 0.19%. Next to amblyopia, injury is the main reason for monocular loss of vision in childhood, however, both are preventable. Information about trauma prevention and the need for adequate ophthalmic care should be emphasized. Regular and repeated screening of visual acuity in children is essential.
The corneal surface of rabbits and vervet monkeys was studied by means of scanning electron microscopy after the influence of the cationic surfactant, benzalkonium chloride. The concentration of the drug was 0.02% or 0.01% and the exposure time was 2 or 4 min. The corneas treated with the drug had characteristic changes with small holes or more extensive lesions of the superficial cell membranes, and loss of microvilli or microplicae. The damage was considered to be due to the lytic effect of benzalkonium chloride upon the plasma membranes.
A laser flare meter, insensitive to corneal, lens, and eye background scattering and calibrated by measurements and theoretical modeling, is reported. Calibration measurements and theoretical calculations of light scattering from albumin solutions were found to agree within the limits of error. The results from in vivo measurements of normal eyes of different ages agreed well with normal protein content of aqueous humor. A special aperture design was used to reduce the unwanted background scattering resulting in signal-to-background ratios between 1:1 and 1:3 for normal eyes. Moderately cataractous eyes, with increased scattering from the lens, could be measured with sufficient accuracy. The reproducibility was measured to be ~ 12%. We studied how the flare is affected by sex, right/left eye, eye color, time of day, pupillary dilation, and an intraocular pressure measurement. No differences of practical importance were found.
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