Causes of blindness among students in blind school institutions in a developing country.

Abstract

Genetic factors are the main causes of childhood blindness in developed countries (Sorsby, I966; Fraser and Friedmann, I967; Merin, Lapithis, Horowitz, and Michaelson, I972; Goldstein, 1972 Chronicle, 1973).Since the early I960S the Eye Departnent of the Hadassah Hebrew University Hospital in Jerusalem has been sponsoring the ophthalmological care in many African countries (Michaelson, 1972). In Malawi sponsoring started in I965. After io years a study was undertaken in order to evaluate the causes of blindness in the past, the current causes of blindness, and to assess the expectations for the future.We report here a retrospective study on the causes of blindness as presented by students in blind school institutions all over Malawi. Patients and methodsTwo hundred and seventy students attending 17 blind school institutions were examined. The location of these schools is shown in the Figure. Admission to them is non-selective and depends on the number of vacant places available at the time of application. However, the following conditions play a role as selective factors. (i) Owing to tradition and culture fewer females than males apply. Therefore the relative proportion between sexes in this study does not reflect the real situation.(2) Blindness due to causes that may influence the life expectancy will not be found and their contribution to 'all' causes of blindness will not be shown in this study.(3) Admission to the blind schools is generally at the age of 4 to 6 years, therefore most cases will represent mainly the causes of blindness in childhood.

Dynamic optical coherence tomography measurements of elastic wave propagation in tissue-mimicking phantoms and mouse corneain vivo

“…5. For the quantification, the density (ρ) of gelatin phantoms was assumed to be 1000 kg∕m 3 and the Poisson's ratio (v) of 0.5 was used to obtain E from Eq. (3).…”

“…Several diseases, such as axial elongation in myopia, pathological deformation in keratoconus, and iatrogenic keratoectasia following corneal refractive surgery can alter biomechanical properties of the cornea and lead to poor vision and even blindness. 3 Thus, the study of the biomechanical properties of cornea can help to detect and diagnose the severity of certain ocular diseases and complement the structural imaging of the eye.…”

Assessing mechanical properties of tissue phantoms with non-contact optical coherence elastography and Michelson interferometric vibrometry

“…For example, keratoconus structurally degenerates the cornea [2], tumors generally stiffen tissue [3], and atherosclerosis hardens the vasculature [4]. Thus, quantifying changes of biomechanical properties of tissue can provide critical information for early diagnosis and effective treatment of various diseases [3,5].…”

In vivoestimation of elastic wave parameters using phase-stabilized swept source optical coherence elastography

“…Alterations in the biomechanical characteristics of the cornea can have a profound influence on its health, structural integrity, and normal function, and can lead to significant visual losses and even to permanent blindness. 1 Therefore, it is critically important to understand the interplay between the mechanical properties of the cornea and its physiological function. Quantitative characterization of the biomechanical properties of the cornea could provide useful diagnostic information for early detection of corneal pathologies and for planning refractive surgery.…”