Ultrastructure studies of a macular dystrophy cornea-case study

Macular corneal dystrophy [MCD] is an autosomal recessive disease characterised by deposition of glycosaminoglycans in corneal. In the present studies we describe ultrastructura] features of a macular dystrophy cornea. Corneal buttons of A 54 years old female patient who was suffering with Macular dystrophy, removed and fixed in freshly prepared 2.5% glutaraldehyde containing 0.05% cuprolinic blue [BDH Ltd, Dorset, U.K.] using acritical electrolyte concentration mode. The tissue was infiltrated in Spurr resin three times [8 hrs each] and polymerised in Spurr resin at 70°C for Shrs. Ultrathin sections were studied with transmission microscope. Ultrastructural studies showed irregular distribution of variable diameter collagen fibrils in disturbed lamellae. The proteoglycans in the stroma were very large and aggregated in large groups around the keratocytes. Keratocytes were also degenerated and full of large vacuoles. There were numerous electron lucent vacuoles distributed in the stroma. Collagen fibrils irregularly distributed and proteoglycans were abnormally large. The progressive development of the clouding in MCD corneas could be due to alteration in the keratan sulphate proteoglycans such as lumican, kerotocan and mimican which normally regulate the uniform distribution of collagen fibrils

Normative values for randot stereoacuity in Saudi children

The aim of this study was to establish the normative values for Randot stereoacuity in Saudi school children aged between 6 and 12 years and to determine the 95% confidence limits for Randot stereoacuity thresholds in Saudi children population. Nine hundred and sixteen [916] male subjects aged between 6 and 12 years of age participated in this clinical study. Case history, distance and near visual acuity, cover test, and external examination were assessed for each subject. Randot stereoacuily tests were subsequently measured at 40 cm for each subject. Eight hundred and twenty three [90%] of the subjects attained 25 seconds of arc or better. The mean Randot stereoacuity was not significantly different [p > 0.05, Tukey-Kramer Multiple Comparison Test] between the different age groups. The range of stereoacuities achieved by subjects for all age groups was 20 to 100 seconds of arc, except for the 11-year old group in which the range was 20 to 70 seconds of arc. We conclude that most Saudi children attain stereoacuity threshold of 40 seconds of arc or better by the age of 12 years. Approximately 99% of all children up to and above the age of 6 years obtain Randot stereoacuity thresholds of 70 seconds of arc or better. These findings should aid in the evaluation of binocular function in young Saudi children

Titmus stereoacuity norms in Saudi primary school children

Purpose This paper presents the result of Titmus stereoacuity tests conducted on Saudi male primary school children. The objective was to establish the Titmus stereoacuity norms in Saudi primary school children. Methods Visual acuity [VA] was measured at 40 cm in all the children attending two primary schools in Riyadh. The total number of subjects examined was 719 and were between the ages of 6 and 13 years. Six hundred and twenty-eight [87.3%] of the subjects had a VA of 6/9 or better monocularly and binocularly [unaided or with current glasses]. Titmus stereoacuity tests were subsequently measured in the latter group. four hundred and sixty-eight [74.5%] of the subjects had 40 arc seconds of stereoacuity. 82[13%] had 50 seconds, 38 [6%] had 60 seconds, 30 [4.8%] had 80 seconds and 10 [1.6%] had 100 seconds. The range of stereoacuity values,for the various age groups are presented. This data established that between the age of 6 to 9 years, the Titmus stereoacuity norm should be 40 to 100 arc seconds, and between the age of 10 to 13 years, the stereoacuity should be 40 to 80 arc seconds, when a child has VA of 6/9 or better