The aim of this study was to establish the prevalence of refractive errors in Jordanian adults of working age, and to study the ocular biometric correlates of refractive error in this population. Refractive error and ocular biometry were measured in 1093 Jordanian adult subjects aged 17-40 years to determine the prevalence of refractive error, and explore structural correlations of ametropia. Refractive error was measured using a Grand-Seiko GR-3100K closed-view infrared autorefractor. Ocular component measurements were made using A-scan ultrasonography and autokeratometry. The prevalence of myopia [spherical equivalent refraction (SER) less than -0.50 DS] and hyperopia (SER greater than +0.50 DS) was 53.71 and 5.67% respectively; 40.62% of the sample was emmetropic (refraction between +0.50 D and -0.50 D inclusive in both principal meridians). The distribution of SER was found to show marked leptokurtosis, exhibiting a peak between plano and 1 D of myopia. Corneal radius, anterior chamber depth, crystalline lens thickness, vitreous chamber depth and axial length (AL) parameters were normally distributed in the population studied. AL to corneal curvature ratio was not normally distributed, and showed marked leptokurtosis. Linear regression analysis showed that AL correlated most closely with spherical equivalent refractive error. This study has established a database of refractive error prevalence and ocular biometric correlates of ametropia in a Middle Eastern population of working age.

Usher syndrome (USH) is an autosomal recessive disorder associated with sensorineural hearing impairment and progressive visual loss attributable to retinitis pigmentosa. This syndrome is both clinically and genetically heterogeneous. Three clinical types have been described of which type I (USH1) is the most severe. Six USH1 loci have been identified. We report a Palestinian consanguineous family from Jordan with three affected children. In view of the combination of profound hearing loss, vestibular dysfunction, and retinitis pigmentosa in the patients, we classified the disease as USH1. Linkage analysis excluded the involvement of any of the known USH1 loci. A genome-wide screening allowed us to map this novel locus, USH1G, in a 23-cM interval on chromosome 17q24-25. The USH1G interval overlaps the intervals for two dominant forms of isolated hearing loss, namely DFNA20 and DFNA26. Since several examples have been reported of syndromic and isolated forms of deafness being allelic, USH1G, DFNA20, and DFNA26 might result from alterations of the same gene. Finally, a mouse mutant, jackson shaker ( js), with deafness and circling behavior has been mapped to the murine homologous region on chromosome 11.

Ophthalmodynamometry was done by 96 normotensive volunteers and 62 hypertensive patients in sitting and supine position. A high correlation between the brachial and ophthalmic blood pressure was found in both groups, and in both positions. The brachial blood pressure of normotensive subjects did not show any difference in both positions. Although the systolic brachial blood pressure did not show significant changes in hypertension, the diastolic--and the calculated mean brachial blood pressure has been slightly but significantly decreased in the supine position. In both groups, normotension and hypertension, the ophthalmic blood pressure was found to be dependent from the level of the systemic blood pressure and the position of patient. It is significantly higher in the supine position than in the sitting position. The higher the systemic blood pressure in the sitting position, the less was the increase of the ophthalmic blood pressure in the supine position.

A comparison of both methods (ODM and ODG) on 100 persons was undertaken. The ophthalmodynamometry was found to be superior. The ophthalmodynamography in its present form, is especially of advantage in cases of anophthalmos, opacity of refracting media, and extreme miosis where ODM can not be applied. In the rest of the cases it may be applied in addition to dynamometry, also in cases with side differences. In measuring thecerebral circulation and testing vasoactive substances dynamometry is superior.

Usher syndrome (US) is clinically and genetically a heterogeneous group of disorders characterized by the association of deafness with retinitis pigmentosa. So far, eight genes responsible for US have been mapped, of which only the gene responsible for the most common form, USH1B, has been identified. The USH1B is a large gene containing 49 exons and encoding for an unconventional myosin‐VIIA (MYO7A). Mutation analysis within the MYO7A gene showed a wide variety of mutations dispersed all over the gene. The present report refines the location of the MYO7A gene relative to microsatellite markers mapped to this region, thereby allowing a reliable and efficient carrier detection by linkage analysis.