Special glasses

child with safety glasses

What will you find in the article?

* Attention! contains optical terms and concepts.

Eye conditions are different and require different approaches and care. Therefore, we will pay attention to special glasses. Some of them are mainly used in medical centers and are not as widely distributed as corrective glasses myopia ,hypermetropia and presbyopia (age-related farsightedness).

The types of special glasses are telescopic, reflex, recumbent, occlusion, mute, polarization, orthopedic and safety glasses.

Correction of amblyopia. Telescopic glasses

What is amblyopia?

It is expressed in severely reduced vision for which there is no apparent reason. Correction of amblyopic eyes is carried out in early childhood. Amblyopia is more commonly known as lazy eye. It does not feed information to the brain. Amblyopia can affect both eyes. It is studied with special tables.

Correction of amblyopia

It is performed with telescopic glasses. They are glasses in which a Galilean telescopic system is placed in front of the amblyopic (lazy eye). It is important that the structure is very light and well centered. They are made to special order. The glasses are programmed to darken the lens in front of the healthy eye. Thus, during a certain time, the lazy eye is activated. Dimming is done thanks to polarization of light.

The glasses increase the image on the retina.

In most cases, the correction is done with obturators (patches that are placed in front of the child's healthy eye to encourage the lazy one to work hard.

child with occluder

Galilean telescope system

Galilean telescopic system

It is used to observe distant objects. Its magnifying power is about 2 times. It consists of a positive objective and a negative eyepiece. It has a small field of view and gives a straight image.

The system dates back to the 17th century, when Galileo Galilei perfected his telescope to observe Jupiter.

Kepler telescopic system

Kepler telescopic system

It provides up to 4x magnification. An additional inversion system is placed in it to observe a straight image.

Telescopic glasses can correct monocularly and binocularly.

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Reflex glasses

reflex glasses

Glasses for the bedridden

They are used for people who suffer from a condition called hemianopsia. As a result of this disease, part of the retina becomes insensitive to light.

For example, when the right halves of the retina of both eyes are affected, objects on the right are seen because they are imaged on the left. In order to be able to observe the objects on the left, a flat mirror is placed in front of one eye. It directs light from the left to the left part of the retina.

A massive plastic frame is used to make these glasses. In one circle, a flat mirror is placed along the vertical axis.

They are used by relatively immobile people. They cannot provide vision correction. Through a prism or mirror, light is directed to the eyes to see an image in a lying position.

The glasses can be ordered in any optician, they are offered as a finished product.

Occlusion glasses (occluders)

These glasses are used by people who need to exclude one eye from the viewing process.

This is done through screens, capsules or frosted glass.

Screens

They are made of opaque material. They are cut according to the shape of the circle (glass) of the frame. With this type of occlusion, the side light is not isolated. If necessary, screens are added to protect from the light entering from the side.

Capsules (obturators)

They represent elements made, mainly of silicone. They are attached by vacuum to the inner surface of the glass. They isolate direct and side light.

The well-known model Carrera 5046 sunglasses also have side protectors. They are made of leather and protect against light entering from the side.

Frosted glass

It is used in emergencies when one eye needs to be closed. For example, diplopia (double vision). The lens in front of the isolated eye is matted from the inner surface, using an abrasive, until a uniform matte is achieved.

Stenope glasses

mural glasses

Stenopey glasses have opaque plates with a small opening in the middle. For greater efficiency it is necessary to isolate the side light.

The aperture is about 2 mm and is located just opposite the pupil.

For the first time these glasses were used to correct irregular astigmatism.

Modern stenopeic glasses are used in eye clinics. They are used to determine the light sensitivity of the eye after surgery.

There are mural glasses with multiple holes that serve to rest the eye. But also, could serve to increase visual acuity.

mural glasses

They can be used for irregular astigmatism. The holes on the plates are about 1-1.5mm.

Now that I think about it, a lot of the alcohol brands years ago were handing out plastic glasses with a plastic grill instead of lenses. They probably wanted to show that besides the relaxing effect that alcohol provides to the nervous system, there are also glasses to give your eyes a break.Β 

Polarization glasses

In these glasses the phenomenon is used polarization of light. Polarizing lenses are used to make them.

Polarizing glasses are used by drivers, fishermen, athletes, etc. They provide good vision by eliminating glare. Glare is eliminated and contrast vision is improved.

There is a European directive which describes the necessary requirements that these glasses must meet. They must have certain qualities such as: light absorption, recognition of traffic signs and traffic light colours, optical properties, etc.

These are the famous polarized sunglasses that are often offered to you in optical stores as soon as you mention that you drive often.

Orthopedic glasses

Orthopedic glasses are used for a condition called ptosis (the eyelid of one eye is continuously lowered). With these glasses, the upper eyelid of one eye is temporarily kept raised. It is then dropped to prevent the eye from drying out.

A ptosis support is attached to a solid plastic frame for the inner top of the crucible.

Glasses with hearing aid

They are glasses in the handle of which a hearing aid is mounted. This gives the wearer the ability to correct both vision and hearing.

It is recommended that the front can be detached from the handles as the hearing aid should not get wet when cleaning.

Protective, safety glasses

They are divided into goggles for sports, hiking and professional protective eyewear.

sports glasses
Goggles for sports and hiking

They should have maximum UV protection and are recommended to be photosolar. They are available with or without dioptric correction. They are used for active outdoor activities such as: hiking, skiing, mountaineering, swimming, fishing, cycling, etc.

woman with protective glasses
Professional safety glasses

Provide protection from mechanical, chemical and physical impacts. Designed for people working with power tools or machine tools. As well as for people working in dusty spaces, dentists, laboratories with harmful radiation.

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