Introduction to Contact Lenses - PowerPoint PPT Presentation

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Introduction to Contact Lenses

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Introduction to Contact Lenses – PowerPoint PPT presentation

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Title: Introduction to Contact Lenses


1
Introduction to Contact Lenses
2
Objectives
  • Describe evolution of contact lenses
  • Describe types of contact lenses
  • Identify basic parameters of contact lenses
  • Identify uses and benefits
  • Describe fitting procedures and care regimens

3
Contemporary History
  • Four significant milestones
  • 1940s development of PMMA (hard lenses)
  • 1970s development of HEMA (hydrogels or soft
    lenses)
  • 1980s development of rigid gas permeable (RGP)
    lenses
  • 1999 development of silicone hydrogel lenses

4
What is a Contact lens ?
  • Contact lens is an Optical device or lens which
    is used to correct Refractive errors,
  • change color of the eye or for therapeutic
    purposes

5
Types of Contact Lens
  • Hard Contact lens - Obsolete as does not allow
    Oxygen to pass through
  • Rigid Gas Permeable lens (semi-soft lens)- allows
    better oxygen transmission.Poor comfort.
    Cumbersome fitting procedure
  • Soft Contact lens - allows good oxygen
    transmission. Highly comfortable. Easy to fit.

6
Conventional Soft Lens Materials
  • HEMA ( Hydroxy Ethyl Methacrylate) is the most
    common material for conventional lenses
  • FDA has divided SCL materials into 4 groups on
    the basis of water content Ionicity
  • Group1- LWC,Non-Ionic
  • Group2 HWC,Non-Ionic
  • Group 3- LWC, Ionic
  • Group 4 HWC, Ionic

7
RGP Lens Materials
  • RGP lenses combine standard PMMA with silicone
  • PMMA is a clear plastic material that is
    impermeable to oxygen
  • Offer excellent vision
  • Easy to handle, durable
  • Simple to care for

8
Silicone Hydrogel Lens Materials
  • Silicone and hydrogel are combined to create a
    revolutionary soft contact lens material
  • Exceptional oxygen permeability
  • Excellent on-eye performance and comfort

9
Wear Modality
  • Wear modality refers to how the contact lens if
    worn by the patient.
  • Wear modality is divided into two groups
  • Daily wear
  • Extended wear
  • Continuous wear

10
Replacement Schedule
  • Replacement schedule refers to how often contact
    lenses are replaced
  • Lenses are generally replaced on a traditional
    schedule or a planned replacement/disposable
    schedule

11
Traditional Contact Lens Wear
  • Patients once wore same pair of lenses until they
    experienced discomfort, or lens was lost or
    torn.Average life of a traditional lens is 1
    year.
  • Today, traditional lens replacement has been
    replaced with Planned Replacement/ Disposable
    schedules

12
Planned Replacement/ Disposable (PRD)
  • Contact lenses are replaced more frequently (one
    to three months)
  • Disposables are discarded at end of wear and
    never reused
  • Disposable may be worn daily or extended wear
    basis

13
Advantages of Contact lens over Spectacles
  • Wider field of view (Improved Peripheral Vision)
  • Active lifestyle
  • No tell tale marks , no sliding down the nose
  • No fogging wih sudden temperature changes
  • Natural Good Looks

14
Advantages of Contact lens over Spectacles
  • Better clarity of Vision
  • Actual size of object is seen unlike in high
    power spectacles
  • IMMENSE SELF-CONFIDENCE
  • See Better, Look Better, Feel Better

15
Indications for Contact Lens Wear
  • Myopia
  • Hyperopia
  • Astigmatism
  • Presbyopia
  • Aphakia
  • Keratoconus
  • Astigmatism secondary to post-op/trauma
  • Corneal protection
  • Corneal healing
  • Occupational requirements

16
Contraindications for Lens Wear
  • Anterior segment inflammation or infection
  • Chronic ocular allergy
  • Certain systemic diseases
  • Ptosis
  • Corneal hyposensitivity
  • Chronic dry eye
  • Poor quality or inadequate tearfilm
  • Occupational incompatibility
  • Noncompliant, unmotivated patient
  • Poor patient hygiene

17
Contact Lens Designand Application
18
Single Vision Spherical Soft Contact Lenses
  • Myopia
  • Hyperopia
  • Presbyopia
  • Aphakia
  • Most widely prescribed contact lenses

19
Toric Soft Contact Lenses
20
Presbyopic Soft Contact Lens Correction
21
Cosmetic Tinted Soft Contact Lenses
22
Therapeutic and Bandage Lenses
  • Promote corneal healing
  • Treat corneal/ocular disease
  • Collagen lenses offer good results

23
Lens Care Systems
  • Deposits composed of protein, lipids, mucin and
    other organic and inorganic substances need to be
    removed
  • Cleaning
  • Surfactant to remove surface deposits
  • Enzymatic to remove protein deposits

24
Lens Care Systems
  • Rinsing
  • Disinfection
  • Chemical disinfection
  • Thermal disinfection
  • Hydrogen peroxide
  • Storage

25
Lens Lubricants
  • Lens lubricants are used when lenses become dry
    and uncomfortable
  • Extended-wear lens patients are encouraged to use
    lubricants prior to sleep and upon waking

26
For Further Queries Contact Ms. Priyanka
Singh Head Optometry Service Email
optometry_at_venueyeinstitute.org
27
End
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