Specifications

supply a full series high quality optical/ophthalmic/medical instrument,CE approvaled

USE

The trial lens sets is suitable for examining refractive errors, such as myopia, hyperopia, astigmatism, persbyopia; Also for examination of strabismus and color blindness. It is essential for ophthalmological protection departments in hospitals, the health care departments in factories, schools and country areas, the refraction rooms in glasses shops, and for physical examination of soldiers and farmers.

METHOD OF USE

II. Trial lenses

(1). Spherical lenses

A spherical lens which is a part of a sphere, has the same curvature at different meridian. The parallel rays passing through it focus into one point (real of virtual) spherical lenses, classified into convex/plus and concave/minus lenses, are used to correction hyperopia, myopia, presbyopia.

(2). Cylindrical lenses

A cylindrical lens which is a part of a cylinder, has the different curvature or refraction at different meridian. The paralleled rays passing through it focus into a line (real of virtual). Cylindrical lenses, classified into plus and minus, lenses, are used to correct astingmatism.

(3). Prism Lens

A prism lens, whose cross section is a wedge, bending rays passing through it to its bottom, is used to examine the eye muscle imbalance including latent strabismus and real strabismus. It is also used for thoptic training.

(4). Occluder

An occluder is made of opague material and is used to enoer the eye that is mot being examined.

(5). Ground glass lens

A ground glass lens, through which only half of the rays falling on it can pass, is used to replace the occluder for children and outdoor activity in order to get their cooperation.

(6). Pinprick lens

A pinprick lens, which is artificial pupol, can improve vision, especially for astigmatism.

(7). Crevice lens

A crevice lens with a central narrow silt on it, allowing only that portion of rays to pass through the slit responding to its dimension, obstructing most of the rays that strike it, is used to determine the existence or non-existence of astigmatism. There will be no astigmatism if the patients' vision becomes better or worse while the slit is located at certain a meridian, astigmatism must exist.

(8). Plain lens

A plain lens, which does not bend rays at all, is use dot detecting false blindness.

(9)Colored lens

Colored lenses include the red, green, blue, yellow, dark brown lenses. They are used to examine the light sense and the visual function of eyes with cloudy media (such as cataract), Double vision, and color blindness may also be detected with these lenses.

(10)Cross cylinder lens

A cross cylinder lens in a combination of two cylindrical lenses of equal power but opposite signs placing at right angle to each other. It is used to refine the power and axles position of the trial cylinder during refraction. Place the cross cylinder in front of the trial cylinder, the patient wears and make one of its axles coincide with the axles of the trial cylinder and then turn the cross cylinder over using the reverse side without changing the hands' position. Ask the patient to compare the power of the cylinder is appropriate.

(11)Wicker lens

Wicker lens is a ribbed lens, made of a row of glass rods which converts a light spot into a streak, the streak is seen by the patient 90 away from the axles of glass rods, "Wicker lens" is used to measure the strength of eye muscle and for examination of latent strabismus and real strabismus. Put the wicker lens in front of one eye, tell the patient to watch, with both eyes, a light spot he watches with his bare eye is just on the line lormed by the wicker lens,

MAINTENANCE

The trial lens sets has passed the quality test and should be taken good care of, prevent it from being scratched when it is put into use, keep clean and dry by wiping it with flannelette cloth after using.