This document summarizes the science behind contact lenses. It discusses the different types of contact lenses including hard, soft, and rigid gas permeable lenses. It explains how contact lenses work by floating on the tear film layer of the eye to refract and focus light. The advantages of contact lenses are excellent vision, comfort, and suitability for active lifestyles. However, disadvantages include greater risk of complications and need for proper handling and lens care.

1. PHYSICS ASSIGNMENT
2017
Labs @ Home
Science Behind contact lenses
Submitted to: Submitted by:
Kanwal Gurbakhsish Kaur Name :- Ajay Pratap Singh Thakur
L A B @ H O M E

2. CONTANT :-
• Introduction
• Types Of Contact Lens
• Working Principle Of Contact Lens
• Spectacles Lens
• Advantages Of Contact Lens
• Disadvantages Of Contact Lens
• Conclusion

3. INTRODUCTION :-
• A thin plastic lens placed directly on the surface of the eye
to correct visual defects.
• Contact lenses can be a great choice for many people,
whether you’re interested in an alternative to glasses or
looking to wear contact lenses for sports or going out
• Artificial device whose front surface substitutes the antr.
Surface of the cornea.

4. TYPES OF CONTACT LENS :-
• Hard Contact Lens
• Soft Contact lens
• Rigid Gas Permeable Lens

5. HARD CONTACT LENS :-
• From Polymethylmethacrylate(PMMA)
• Diameter of 8.5 – 10 mm
• Advantages :- High optical quality, stability, light weight,
durable & cheap
• Disadvantages :- corneal abrasions , stable tear film

6. SOFT CONTACT LENS :-
• From Hydroxymethymethacrylate(HEMA)
• Diameter of 1 – 2 mm
• Advantages :- Comfortable, well tolerated
• Disadvantages :- Wettability, can get torn, limited life

7. RIGID GAS PERMEABLE CONTACT LENS :-
• Material permeable to oxygen
• Hard, but called as semisoft lenses
• Manufactured form :-
1. Copolymer of PMMA(Polymethylmethacrylate)
2. Silicone containing vinyl monomer
3. Cellulose acetate butyrate

8. WORKING PRINCIPLE OF CONTACT LENS :-
• They float on the tear film layer on the surface of the cornea.
Modern contacts are much more than small eye glass lenses
that fit onto your eyes. They do, however, function much like
regular eye glasses refracting and focusing light so that
objects appear clearly.

9. SPECTACLES LENS :-
• A corrective lens is a lens worn in front of the eye, mainly
used to treat myopia, hyperopia, and presbyopia.
• spectacles are worn on the face a short distance in front of
the eye. Contact lenses are worn directly on the surface of
the eye.
• Types of spectacles lens :-
1. Concave 2. Convex

11. ADVANTAGES OF CONTACT LENS :-
• Excellent vision
• Require little or no cleaning
• Comfortable to wear
• Good for eye health
• Great for active lifestyles
• Relatively long life

12. DISADVANTAGES OF CONTACT LENS :-
• It is used very careful
• Handling may be more difficult
• Lens care also requires more time
• Could increase risk of complication
• Require regular office visit for follow-up care

13. CONCLUSION :-
• Contact lens are generally safe as long as they are
used correctly.
• If you are wearing disposable or planned
replacement lenses, you will have to carefully follow
the schedule for throwing away used lens.