Ophthalmic glass lens materials and manufacturing
Glass: Crown glass , barium , flint glass , titanium oxide glass, lanthanum crown glass
TEAR FILM
The tear film is a complex mixture of substances that are produced by various sources on the surface of the eye, such as the lacrimal gland, accessory lacrimal glands, meibomian glands, and goblet cells. This film covers the surface of the eye, which includes the corneal and conjunctival epithelia, serving as a barrier between these … Read more
Properties of Ophthalmic lens
Optical properties: The optical properties of ophthalmic lenses encompass their unique characteristics that enable them to accurately refract and focus light, resulting in clear and precise vision. Mechanical properties: The mechanical properties of ophthalmic lenses encompass their physical attributes, including durability, flexibility, and resistance to impact or breakage, ensuring they can withstand everyday use and … Read more
Aberration in Ophthalmic lenses
Aberration refers to the inability of a lens to create a perfect image of an object, resulting in imperfections in the formation of images within an optical system.
Types of Bifocal lens
When a patient needs separate vision correction for both distance and near vision, they can opt for lenses that integrate these corrections into two distinct areas on each lens. Each area possesses its own focal properties tailored for specific distances. Bifocals, as their name implies, consist of two distinct lenses with different focal points, accommodating … Read more
Progressive Addition Lenses
Progressive addition lenses are single-piece lenses that feature a smooth transition in curvature across the lens surface. The curvature gradually increases from the upper distance portion to the lower near portion. Unlike bifocal or trifocal lenses, progressive lenses offer a seamless solution for individuals with presbyopia, providing optimal dioptric power for all distances. This ensures … Read more
AC/A ratio (Accommodative convergence/ Accommodation ratio)
Accommodative convergence/ Accommodation ratio also known as AC/A ratio, is a measurement of changes in accommodative convergence in prism diopters induced when the patient exert or relax 1 diopter of accommodation. Changes in the accommodation are either evoked by placing plus lens which relaxes accommodation or by minus which activate accommodation or when a person … Read more