FREE ABO Contact Lenses Questions and Answers
What is the main advantage of giving the surface of RGP lenses a "plasma treatment"?
RGP lenses are surface treated with plasma to increase the lens's wettability and surface lubricity. Through the reduction of surface tension and improvement of tear distribution over the lens, this treatment alters the lens surface to make it more compatible with the tear film, improving comfort.
Why are UV-blocking compounds added to the materials used to make contact lenses?
By preventing damaging UV rays from reaching the cornea and internal structures of the eye, UV-blocking chemicals are added to contact lens materials with the aim of lowering the wearer's risk of cataract development and other ocular disorders associated with UV exposure.
Is it possible to heat a frame till it yields to its own weight?
"Simultaneous vision" for presbyopia patients wearing multifocal contact lenses means:
The feature of multifocal contact lenses known as "simultaneous vision" refers to the ability of the wearer's eye to simultaneously receive images from the near and far zones. Depending on the viewing distance, the brain then chooses the clearest image, enabling continuous vision at various ranges without the need for manual correction.
"Apical clearance" in the context of rigid gas permeable (RGP) lens fit refers to:
When discussing RPG lenses, apical clearance refers to the lens's vaulting over the corneal apex while preserving a little space between the lens and the cornea that is moistened with a thin coating of tears. This fitting technique is crucial for facilitating tear exchange, improving comfort, and guaranteeing that the cornea receives enough oxygen.
Why are rigid gas permeable (RGP) lenses designed with a "back surface toric" design for specific corneal shapes used in this way?
RGP lenses feature a rear surface toric design to better fit and conform the lens to the toric, or irregularly shaped, cornea.
When wearing soft contact lenses, "lens dehydration" is a problem that can cause discomfort. What is the typical cause of this problem?
Low humidity settings can make lens dryness worse for people who wear soft contact lenses. Under some circumstances, the water in the hydrogel substance of the lens may evaporate more quickly than usual, causing lens shrinkage and increased friction between the lens and the surface of the eye to produce discomfort.
The following factors are most strongly linked to the development of microbial keratitis in contact lens wearers:
the possibility of getting the serious corneal infection known as microbial keratitis. is most closely linked to prolonged (overnight) contact lens usage of any kind. Due to the possibility of bacterial contamination and decreased oxygen supply to the cornea when you sleep, this practice can greatly raise your risk of infection.
Which of the following is MOST important for astigmatic patients receiving toric soft contact lens fittings in order to ensure good visual acuity?
For astigmatic patients, the stabilizing mechanism of toric soft contact lenses is essential to achieving the best possible isual acuity. By maintaining the lens's right orientation on the eye, this mechanism makes sure that the astigmatic correction appropriately matches the astigmatism of the eye.
When comparing silicone hydrogel contact lenses to conventional hydrogel lenses, what is the main mechanism that enhances oxygen permeability?
The main way that silicone hydrogel contact lenses increase oxygen permeability is by adding silicone to the lens material. Compared to conventional hydrogel materials, which rely primarily on water content to assist oxygen transmission, silicone permits noticeably more oxygen to reach the cornea.
Why is it frequently required to use a specially developed keratoconus lens instead of a conventional RGP lens when fitting contact lenses for a patient with keratoconus?
Patients with leratoconus require specially constructed keratoconic lenses to accommodate the conical shape of their cornea. Because these lenses are made to fit over the irregular shape of the cornea, they ensure a more stable fit and the proper amount of refractive correction, which improves comfort and visual acuity.