Trail set or trial case and vision testing equipment
What is trail set ?
Trail set means a box of containing set of concave and convex lenses, spherical and cylindrical lenses, and required accessories for eye vision testing and correction.
Trail set is also known as trail case or vision testing and correction box.
Components present in trial set or case are
- Spherical power lenses
- Cylindrical power lenses
- Pinhole
- Occluder
- Stenopaic slit
- Trail frame
- Red and green filter
- Prism
Uses of trial case
Trail case provide biggest role in ophthalmic practice. It is very very essential and important equipment and accessories to provide eye care service.
Ophthalmic practice starting from the trail case and set.
Below are the some of the uses of trial set
• It uses for note the visual acuity of eye.
• used for to correction of the visual problem with lenses.
• Occluder is used for to close the one eye to see the uniocular vision testing.
• Stenopaic slit is essential for see the optical axis of eye.
• The pinhole is used for to see the better maximum correction of the eye.
• Red and green filter is used for in duochrome test. Duochrome test used for to see the given refractive correction is proper, undercorrection and overcorected.
Spherical power lenses
Trial set include of spherical power lenses this lenses are available in two form plus spherical power and minus spherical power.
Plus spherical power is used for correction of hypermetropia and pressbyopia. It is convex spherical lenses and structure of central thick and peripheral thin. When you see through this lens images magnify and moment of the images opposite direction when you move the lenses.
Minus spherical power lenses used for two correction of myopia. It is a concave spherical power lenses and have a structure of Central thin and peripheral thick. When you see through this lens images minify and image move the same direction when you move the lenses.
Cylindrical power lenses
Electrical power lenses used for to correction of astigmatism refractive error. Cylindrical power lenses also have a two form Plus and minus power lenses.