OCULAR MANIFESTATION OF SYSTEMIC INFECTIONS
The eyes are a window to the soul, and they can also provide important clues to the presence of systemic infections. Many infections can cause ocular manifestations, which are changes…
OPTICS OF THIN LENS
In optics, a thin lens is a lens with a thickness (distance along the optical axis between the two surfaces of the lens) that is negligible compared to the radii…
Methods of taking visual acuity in younger children
The testing of visual acuity in infants and children has been treated separately from the testing of adults because infants and children often can’t be tested with the same materials…
Anti-Reflection Coating: The Optometrist & Perspective
Anti reflection coatings minimize the reflection of one or many wavelengths and are typically used on the surface of lenses so that less light is lost. A simple coating can…
What is spherical aberration
Spherical aberration is an optical aberration that occurs when all incoming light rays after passing through spherical surface end up focusing at different points . Lights rays that strike a…
Retinoblastoma
Retinoblastoma is a cancer of the eye that is usually diagnosed by the age of 6 years, with the majority of these cases seen by age 3 year. The disease…
Importance of Keratometry in Contact Lens practice
Keratometry is a simple, rapid and non-invasive test. It has some limitations. It measures the curvature of the anterior corneal surface usually across a fixed chord length of 2 to…
ASPHERIC LENSES
Aspheric lenses have non-spherical shapes, and have a more complex front surface, such as ellips, parabola, hyberbola, as well as toric which resembles a section of the surface of a…
Abnormal retinal correspondence
In a state of normal binocular single vision, there exists a precise physiological relationship between the corresponding points of the two retina. Thus, the foveae of two eyes act as…
ADVANCES IN THE TREATMENT OF PRESBYOPIA
Presbyopia affects 1.8 billion people worldwide, according to the World Health Organization (WHO). The American Academy of Ophthalmology (AAO) describes it as a common age-related decline in the eye’s near…
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