Tear function abnormalities in down syndrome

Down syndrome is a common chromosomal anomaly, characterized by specific facial features, eye anomalies with repeated ophthalmic infections. The integrity of the ocular surface is maintained by the tear film. To determine the presence of tear function changes in children with Down syndrome and their relation with the development of ophthalmic diseases. Tear film was evaluated by the ferning test and breakup time [BUT] measurement in 23 patients [46 eyes] confirmed as having Down syndrome by cylogenetic analysis and 20 normal control children [40 eyes] with matched age and sex. There was an alteration in both ferning and BUT tests in children with Down syndrome compared to controls. Abnormal ferning test was found in 28 out of 46 tear samples from the patient's eyes compared to 2 out of 40 normal control eyes. BUT test results showed that the preocular tear film stability was poor in 65.2% of patients' eyes, average in 26.1% and good in only 8.7% of their eyes; while controls had good and average tear film stability each representing 50% of eye's number. These tear function abnormalities may have a role in the frequent infectious pathologies found in the anterior eye segment in patients with Down syndrome which necessitates applying new stringent strategies for ophthalmologic care and management of these patients

Ophthalmogenetic and epidemiological studies of Egyptian children with mental retardation

Mental retardation [MR] is a congenital or early onset lifelong impairment of cognitive adaptive functioning or daily living skills. It is a serious and lifelong disability that places heavy demands on society and the health system. The prevalence of visual and ocular disorders in children with MR is high and can influence sensory-motor development and learning ability. Assessment of the genetic and epidemiologic aspects of mental retardation and clarifying the ocular and visual problems among mentally disabled children. A cross-sectional hospital based study was conducted, through a period of two years, included 190 children under 18 years of age with mild to profound intellectual disabilities who were diagnosed among 480 cases referred to the Genetic clinic, Research Institute of Ophthalmology for genetic diagnosis and counseling. The definition of MR and the criteria for diagnosis were adopted from the World Health Organization [WHO] classification. The etiology of MR was specified by obtaining information about the personal and family history that included a three generation pedigree analysis, with special attention to the presence of similar cases, thorough clinical examination including complete neurological evaluation, chromosomal and other investigative studies. Ophthalmologic examination included visual acuity testing, ocular motility and examination of the external eye and anterior segment; cycloplegic refraction and fundus examination. One hundred and ninety patients representing 39.6% of the total examined cases in two years were classified etiologically into 6 groups. Specific causes were found in 161 cases [84.7%] and the etiology was unknown in 15.3% of children. Metabolic and chromosomal disorders comprised the most common etiological problems of the examined mentally retarded children in this study. The percentage of mild, moderate, severe and profound MR was 67.5%, 26%, 5.8% and 0.7%, respectively. Family history was positive in 34.7% of patients and autosomal recessive inheritance was the commonest mode of transmission [48.4%] that reflects the high percentage of consanguineous marriages among Egyptians. Microscopically visible chromosomal anomalies of intellectually disabled patients included 25 numerical and 11 structural aberrations. Errors of refraction and strabismus were the most common in children with chromosomal disorders [24.7%] and [28.1%] respectively. While the highest percentage of optic atrophy, retinal dystrophy, microphthalmia, cataract and corneal opacities were diagnosed in children with metabolic disorders representing 76.2%, 93.3%-, 38.5%, 50% and 80% of cases diagnosed in all categories respectively. In this study, metabolic and chromosomal disorders represented the most common etiological problems among the examined mentally retarded children with the highest proportion of specific ocular and visual problems represented among them to the extent that the eye could be considered as a window for their diagnosis. In most cases, diagnosis will assist families in understanding the condition, its prognosis and recurrence risks; more epidemiological studies have to be undertaken to determine the magnitude of the problem and its pattern of distribution in our country. The results also emphasize the need for establishing an efficient system to provide regular ophthalmic care for children with mental retardation

Genetic and environmental factors in different types of age-related cataract among Egyptians

The present study included 280 patients with age-related cataract [153 males and 127 females] and 296 controls with similar age and sex distribution. All cases and controls were subjected to thorough personal and family history taking including consanguinity, occupation, residency, diabetes mellitus, hypertension, smoking, family history of age-related cataract and family pedigree analysis. Full clinical examination also included complete ophthalmological evaluation to determine the type of cataract using slit-lamp examination and visual acuity measurement. Seventy-five patients and 25 controls were subjected to the following investigations: Estimation of serum total protein, serum albumin and globulin levels, albumin/globulin [A/G] ratio, hemoglobin [Hb] level and red blood cells [RBCs] count. Statistical analysis was conducted using SPSS program for calculating t test, X2 test and multiple logistic regression analysis. The present study revealed that mixed cataract [i.e. presence of more than one type of cataract] was the commonest type of age-related cataract in Egypt [48.9% of cases]. Positive family history, consanguinity and exposure to ultraviolet irradiation were universal risk factors for all types of cataract among Egyptians. Diabetes mellitus was associated with nuclear and posterior subcapsular types of cataract, while hypertension had its effect on both cortical and posterior subcapsular types. Biochemical analysis revealed that the risk of age-related cataract increases with decreased level of serum total protein, decreased serum albumin and globulin levels, decreased RBCs count and hemoglobin level