Power-adjustable spectacle lenses, based on the Alvarez-Lohmann principle, can be used to provide affordable spectacles for subjective refractive errors measurement and its correction. A new mechanical frame has been designed to maximize the advantages of this technology. The design includes a mechanism to match the interpupillary distance with that of the optical centers of the lenses. The fra...

Purpose: The prevalence of myopia in school-age children and rural area in Taiwan has increased dramatically. The aim of this study was to explore the associated factors of myopia in rural adolescents. Methods: A cross sectional design with a rural junior high student was invited to participate in this study. The relationship between refraction error (RE), spectacle fitting condition, and ocula...

PURPOSE To compare spectacles bought online with spectacles from optometry practices. METHODS Thirty-three participants consisting of single vision spectacle wearers with either a low (N = 12, mean age 34 ± 14 years) or high prescription (N = 11, mean age 28 ± 9 years) and 10 presbyopic participants (mean age 59 ± 4 years) wearing progressive addition lenses (PALs) purchased 154 pairs of spec...

Abstract Facial defects not only impact on the function and quality of life but also affect the psychological well-being and social behavior of patients. A nasal prosthesis can re-establish the esthetics and anatomical contour in patients with mid-facial defects, often more effectively than surgical reconstruction. For successful results, many factors such as retention, texture, color match ...

Background: Recent evidence points to the use of spectacles alone in the treatment of anisometropic amblyopia. However, the impact of this treatment on the restoration of binocular vision is often not considered. Case Report: Patient M.Z., aged 7 years, showed 3.5D of anisometropia which was coupled with a best corrected visual acuity of 6/38 in the more hyperopic eye (6/6 in the non-amblyopic ...

Spectacle-mounted telescopic systems are prescribed for individuals with visual impairments. Bioptic telescopes are typically mounted toward the top of the spectacle lens (or above the frame) with the telescope eyepiece positioned above the wearer’s pupil. This allows the wearer to use up and down head tilt movements to quickly alternate between the unmagnified wide view (through the carrier le...

BACKGROUND Uncorrected refractive errors are the commonest cause of visual impairment in children, with myopia being the most frequent type. Myopia usually starts around 9 years of age and progresses throughout adolescence. Hyperopia usually affects younger children, and astigmatism affects all age groups. Many children have a combination of myopia and astigmatism. To correct refractive errors,...

Spectacle corrections worn in a frame with a faceform tilt should be used with effective spherocylindrical parameters. For the case of oblique central refraction, Keating presented a procedure to determine these parameters in a third-order approximation. The central equation of his approach, the effective dioptric power matrix, is partly the result of an educated guess. Based on the equations o...