Unit C Lesson C10 Vision Enhancing Technologies
Completion requirements
Lesson C10: Vision-enhancing Technologies
Video Lesson
Certain eye conditions prevent people from having clear eyesight. Watch this video to learn about technologies that improve and enhance vision.
Lesson C10: Vision-enhancing Technologies
Figure C.3.10.1 – Sunglasses block excess light from entering the eyes.
Figure C.3.10.2– The Inuit made snow goggles from walrus tusks and animal skins.
Figure C.3.10.3– Modern ski goggles prevent snow blindness.
Reading and Materials
for This Lesson
Science in Action 8
Reading: Pages 234–235
Materials:
No additional materials are needed for this lesson.
Looking Good and Protecting your Eyes
Modern sunglasses are a fun fashion accessory, but they also stop excess light from entering the eyes. While most sunglasses block some visible light, the most effective sunglasses block harmful ultraviolet (UV) radiation from the Sun. Excess UV radiation can burn and damage the eye’s cornea, like a sunburn.
Long before modern sunglasses, the Inuit wore snow goggles with thin slits, carved from driftwood or walrus tusks. On sunny Arctic days, visible light and UV rays reflect off the white surface of snow. Too much reflected light entering the eye makes it difficult to see clearly and can cause snow blindness, a painful burn of the cornea. The thin slits in Inuit snow goggles permit a small amount of light to reach the eyes. However, the goggles block most light, to protect against snow blindness.
Modern sunglasses are a fun fashion accessory, but they also stop excess light from entering the eyes. While most sunglasses block some visible light, the most effective sunglasses block harmful ultraviolet (UV) radiation from the Sun. Excess UV radiation can burn and damage the eye’s cornea, like a sunburn.
Long before modern sunglasses, the Inuit wore snow goggles with thin slits, carved from driftwood or walrus tusks. On sunny Arctic days, visible light and UV rays reflect off the white surface of snow. Too much reflected light entering the eye makes it difficult to see clearly and can cause snow blindness, a painful burn of the cornea. The thin slits in Inuit snow goggles permit a small amount of light to reach the eyes. However, the goggles block most light, to protect against snow blindness.
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Sunglasses
Watch these videos to learn more about how sunglasses block light from the eyes.
Watch these videos to learn more about how sunglasses block light from the eyes.
Figure C.3.10.4– Early eyeglasses were held up to the face.
Figure C.3.10.5– Bifocals contain two different lenses.
Figure C.3.10.6– Many people wear glasses for only one purpose, such as reading or driving.
Eyeglasses
Eyeglasses were invented during the Middle Ages. Originally, eyeglasses contained glass lenses. People held eyeglasses up to their faces when they wanted to see clearly. Eventually eyeglasses were redesigned with frames that fit over the ears.
As people get older, they tend to develop multiple vision problems. Bifocals are eyeglasses that correct multiple vision issues. Bifocal lenses often have a line in the middle where the two types of lenses are joined. The lower half of bifocal lenses allows people to see close objects clearly. The upper half of bifocal lenses enables people to see distant objects clearly.
Most modern eyeglass lenses are made with lightweight, durable, and scratch-resistant polycarbonate plastic. However, traditional eyeglasses are made to specifically fit one person’s vision needs. This is not very practical for people in developing countries who do not have easy widespread access to vision-testing equipment. To give people easier access to eyeglasses, an inventor developed a set of self-adjusting glasses with flexible, liquid-filled, plastic lenses. A person can adjust the shape of the lenses themselves, eliminating the need to visit an optometrist.
Eyeglasses were invented during the Middle Ages. Originally, eyeglasses contained glass lenses. People held eyeglasses up to their faces when they wanted to see clearly. Eventually eyeglasses were redesigned with frames that fit over the ears.
As people get older, they tend to develop multiple vision problems. Bifocals are eyeglasses that correct multiple vision issues. Bifocal lenses often have a line in the middle where the two types of lenses are joined. The lower half of bifocal lenses allows people to see close objects clearly. The upper half of bifocal lenses enables people to see distant objects clearly.
Most modern eyeglass lenses are made with lightweight, durable, and scratch-resistant polycarbonate plastic. However, traditional eyeglasses are made to specifically fit one person’s vision needs. This is not very practical for people in developing countries who do not have easy widespread access to vision-testing equipment. To give people easier access to eyeglasses, an inventor developed a set of self-adjusting glasses with flexible, liquid-filled, plastic lenses. A person can adjust the shape of the lenses themselves, eliminating the need to visit an optometrist.
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Correcting Vision Problems
This video reviews how eyeglasses correct different types of vision problems.
This video reviews how eyeglasses correct different types of vision problems.
Watch these two videos to learn more about self-adjusting glasses.
Figure C.3.10.7– Contact lenses fit directly over the eye’s cornea.
Figure C.3.10.8– Contact lenses are made from soft, transparent plastic.
Figure C.3.10.9– Contact lenses are made to improve vision while not injuring the eye they sit on.
Alternatives to Eyeglasses – Contacts
Contact lenses are small corrective lenses that fit directly over the eye’s cornea. Contact lenses have many advantages compared to eyeglasses. Contacts don’t fall off a person’s face during sports activities. They allow people to have clear side vision, which is important in sports and driving. Contact lenses don’t fog up in cold weather.
Early contact lenses were made of glass and covered the entire eye. After the 1970’s, the design of contact lenses changed. They covered just the cornea and were made from soft, bendable plastics. Newer contact lenses are made with silicone, which lets more oxygen into the eye and reduces the risk of irritation.
Contact lenses are small corrective lenses that fit directly over the eye’s cornea. Contact lenses have many advantages compared to eyeglasses. Contacts don’t fall off a person’s face during sports activities. They allow people to have clear side vision, which is important in sports and driving. Contact lenses don’t fog up in cold weather.
Early contact lenses were made of glass and covered the entire eye. After the 1970’s, the design of contact lenses changed. They covered just the cornea and were made from soft, bendable plastics. Newer contact lenses are made with silicone, which lets more oxygen into the eye and reduces the risk of irritation.
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Contact Lenses
Watch this video to learn more about the invention of the contact lens.
Watch this video to learn more about the invention of the contact lens.
Figure C.3.10.10– Laser eye surgery fixes vision problems.
Figure C.3.10.11– Lasers make precise cuts in the eye.
Figure C.3.10.12– Laser eye surgery is often done in a short time, in simple operating theatres.
Alternatives to Eyeglasses – Laser Treatment
Lasers are used during eye surgery to correct different vision problems. Some people get laser eye surgery so they don’t have to wear eyeglasses anymore. The cornea of the eye is curved and helps to refract light. Laser eye surgery reshapes the cornea slightly. This changes the angle of refraction, making images form directly on the retina.
Lasers are increasingly being used in cataract surgery to make precise incisions, instead of a knife. Laser energy can also dissolve the cloudy lens of a cataract. Recovery and healing from laser cataract surgery is much faster than with traditional eye surgery with a scalpel.
Laser eye surgery is expensive and can damage vision if not done carefully. However, many people feel that the benefits of laser eye surgery greatly outweigh the risks.
Lasers are used during eye surgery to correct different vision problems. Some people get laser eye surgery so they don’t have to wear eyeglasses anymore. The cornea of the eye is curved and helps to refract light. Laser eye surgery reshapes the cornea slightly. This changes the angle of refraction, making images form directly on the retina.
Lasers are increasingly being used in cataract surgery to make precise incisions, instead of a knife. Laser energy can also dissolve the cloudy lens of a cataract. Recovery and healing from laser cataract surgery is much faster than with traditional eye surgery with a scalpel.
Laser eye surgery is expensive and can damage vision if not done carefully. However, many people feel that the benefits of laser eye surgery greatly outweigh the risks.
Watch More
Laser Eye Surgery
Watch this video to learn more about laser eye surgery.
Watch this video to learn more about laser eye surgery.
Lasers are increasingly used to remove cataracts. Watch these two videos to learn more about cataract surgery.
Connections
Figure C.3.10.13– The military uses night vision goggles.
Figure C.3.10.14– Night vision goggles help people see in dim lighting.
Figure C.3.10.15– Security cameras often have night vision technology.
>> Night Vision Technology
Humans don’t see very well at night. Night vision goggles improve human vision in dimly lit situations. Light enters night vision goggles and strikes a light-sensitive plate. The small amount of light that strikes the plate causes electricity to flow inside the goggles. The electricity creates a bright image on a second screen, similar to a television. The image looks like the original object, but its brightness is enhanced by the screen.
Night vision technology is used in consumer goods as well. For example, many security cameras have night vision so buildings and rooms can be watched while it is dark. These cameras use infrared lamps to provide the ‘light’ required to see where there is no visible light available.
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Seeing in the Night
Watch this video to learn more about night vision technology.
Watch this video to learn more about night vision technology.
Connections
Figure C.3.10.16– Macular degeneration occurs when retina cells break down.
Figure C.3.10.17– Vision-impaired people rely heavily on their other senses.
Connections – Technology
>> Artificial Eyes
Sometimes people lose their sense of sight completely, due to accidents or diseases. For example, blindness is a potential side complication of diabetes. Elderly people sometimes experience macular degeneration, which causes their retinal light-sensing cells to stop working.
Engineers and scientists are developing new technologies that act as artificial eyes, to restore vision to blind people. Artificial eye technology involves implanting a tiny computer chip sensor on the retina, which can send messages to the brain. Special eyeglasses collect light and interpret it as electrical signals. The electrical signals in the glasses send signals to the eye computer chips, which then send a signal to the brain.
>> Artificial Eyes
Sometimes people lose their sense of sight completely, due to accidents or diseases. For example, blindness is a potential side complication of diabetes. Elderly people sometimes experience macular degeneration, which causes their retinal light-sensing cells to stop working.
Engineers and scientists are developing new technologies that act as artificial eyes, to restore vision to blind people. Artificial eye technology involves implanting a tiny computer chip sensor on the retina, which can send messages to the brain. Special eyeglasses collect light and interpret it as electrical signals. The electrical signals in the glasses send signals to the eye computer chips, which then send a signal to the brain.
Watch More
Replacement Eyes
Scientists are developing artificial retinas. Watch these videos to see some different types of retinal technology.
Scientists are developing artificial retinas. Watch these videos to see some different types of retinal technology.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit C Lesson 10 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here.
- ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
-
REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
- CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Be a Self-Check
Superhero!
Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
The man has become farsighted, because he can’t see close objects clearly. Reading glasses with a convex lens would help images to form on the retina, instead of behind the retina.
Some advantages of eyeglass technology include:
Some disadvantages of eyeglass technology include:
- Eyeglasses correct most vision problems easily.
- Eyeglasses are relatively inexpensive.
Some disadvantages of eyeglass technology include:
- Eyeglasses can fall off the face during sports activities.
- People need to be tested by an optometrist to get a prescription specific to their eyes.
Some advantages of laser eye surgery include:
Some disadvantages of laser eye surgery include:
- People with vision problems don’t need to wear eyeglasses anymore.
- Laser eye surgery heals relatively quickly.
Some disadvantages of laser eye surgery include:
- Laser eye surgery is expensive.
- Laser eye surgery can cause vision damage if it is not done carefully.
Light and UV rays reflect off white snow. Too much light in the eyes can make it difficult to see, and can cause painful snow blindness.
The student is nearsighted, because she can’t see distant objects clearly. Eyeglasses with a concave lens would help images to form on the retina, instead of in front of the retina.