Title: Introduction to Contact Lenses
1Introduction to Contact Lenses
2Objectives
- 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
3Contemporary 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
4What 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
5Types 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.
6Conventional 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
7RGP 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
8Silicone 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
9Wear 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
10Replacement 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
11Traditional 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
12Planned 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
13Advantages 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
14Advantages 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
15Indications for Contact Lens Wear
- Myopia
- Hyperopia
- Astigmatism
- Presbyopia
- Aphakia
- Keratoconus
- Astigmatism secondary to post-op/trauma
- Corneal protection
- Corneal healing
- Occupational requirements
16Contraindications 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
17Contact Lens Designand Application
18Single Vision Spherical Soft Contact Lenses
- Myopia
- Hyperopia
- Presbyopia
- Aphakia
- Most widely prescribed contact lenses
19Toric Soft Contact Lenses
20Presbyopic Soft Contact Lens Correction
21Cosmetic Tinted Soft Contact Lenses
22Therapeutic and Bandage Lenses
- Promote corneal healing
- Treat corneal/ocular disease
- Collagen lenses offer good results
23Lens 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
24Lens Care Systems
- Rinsing
- Disinfection
- Chemical disinfection
- Thermal disinfection
- Hydrogen peroxide
- Storage
25Lens 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
26For Further Queries Contact Ms. Priyanka
Singh Head Optometry Service Email
optometry_at_venueyeinstitute.org
27End