A DETAILED PRESENTATION COVERING ALL ASPECTS OF CONTACT LENSES.TYPES, USES , MAKE, CARE AND MATERIAL.

1. Dr. ARVIND KUMAR MORYA
MBBS,MS OPHTHALMOLOGY (GOLD
MEDALIST),MNAMS,CATARACT(MICS),GLAUCOMA,PAEDIATRIC
OPHTHALMOLOGY,STRABISMUS,REFRACTIVE AND MEDICAL RETINA
SERVICES.
ASSOCIATE PROFESSOR AND UNIT HEAD
DEPARTMENT OF OPHTHALMOLOGY
AIIMS JODHPUR

2. DEFINITION
 Artificial visual device
 Correct refractive error by substitute
anterior surface of cornea.

3. HISTORY OF CONTACT LENS
 1508, Leonardo Da Vinci
used bowl half filled with
water.
 1637, Descartes used tube
filled with water.
 1887, Muller used glass
shell.

4.  1888, Fick formulated term C.L.
 Initially 2 types were available-
- Blown glass lens from Muller
- Ground glass lens from Zeiss
 1937, Feinbloom 1st used plastic
polymer for manufacture.
HISTORY OF CONTACT LENS

5. IDEAL MATERIAL
BIOCOMPATIBILITY
Should not harmful.
OPTICAL PROPERTY
 Transparency
 Refractive index

6. PHYSICAL
PRORERTIES
Wettability
 Porosity & permeability
 High water content
 Heat resistance
 Specific gravity
Scratch resistance
IDEAL MATERIAL

7. OXYGEN TRANSMISSIBILITY
DK/K
D= Diffusion coefficient
(cm/sec)
K=solubility of gas in
material(cm3/cm2mmhg)
L= thickness of
material(mm)
Depends on:
permeability of lens material
Thickness of lens
Temperature at which test is
performed

8. OXYGEN PERMEABILITY
Low Dk material
-Below 20
Mid Dk material
-20 to 40
High Dk material
-40 to 60
Hyper Dk material
-Above 60

9. OXYGEN PERMEABILITY
Daily wear, the recommended Dk/t
of a contact lens is around 30
Low oxygen transmissibility can result
in corneal changes:
- Microcysts
- Polymegathism
- Corneal Ph
- Edema
- Blebs

10. WETTABILITY
 The angle that the edge of a bead of water
makes with the surface of a contact lens
called a wetting angle.
 The smaller the wetting angle the greater
the wettability of lens.

11. Meets corneal ’s oxygen
requirements
Physiologically inert
Biocompatibility
Excellent in vivo wetting
Resists spoliation
IDEAL CONTACT LENS MATERIAL

12. Dimensionally stable
Durable
Optically transparent
Requires minimal patient care
Cost effective
Easily moldable
IDEAL CONTACT LENS
MATERIAL

13. CONTACT LENS DESIGN
1. Monocurve / single-cut lens
2. Bicurve
3. Tricurve
4. Multicurve
5. Toric lens- has toric back surface
6. Bitoric lens-
Prism blast lenses
Truncated lenses
7. Lenticular lenses
8. Bifocal lenses

15. INDICATIONS
 Patient best suited to Contact Lens is
one who wants TO SEE BETTER
and BE SEEN BETTER without
glasses.

16. OPTICAL INDICATIONS
 Myopia / Hypermetropia /
Astigmatism
 Presbyopia
 Aphakia
 Anisometropia & Anisoconia
 Keratoconus

17. COSMETIC INDICATON
 Aniridia
 Albinism
 Coloboma / Large iredectomy
 Heterochromia
 Microcornea / Microphthalmos
 Corneal scars
 Inoperable cataract

18. OCCUPATIONAL INDICATION
 Actors / public speakers
 People using telescope / microscope
 Sportsman
 Protection from steam,
spray, mist etc.

19. THERAPEUTIC
[ BANDAGE SOFT C.L.]
 Decreases pain
 Prevent mechanical trauma by
touch
 Increases proper hydration and
proper healing
 Corneal edema
 Corneal perforation
 Corneal burns
 Corneal grafts

20.  Bullous keratopathy
 Leaking conjunctival blebs
 Keratitis
 Symblepharon
 Lagophthalmos
 Chronic and indolent ulcer
THERAPEUTIC
[ BANDAGE SOFT C.L.]

21. THERAPEUTIC
[ BANDAGE SOFT C.L.]
 Trichiasis / entropion
 Post pterygium operation
 Dry eye syndrome
 For drug delivery(glaucoma)
 Melenosis of conjunctiva – use to
deliver high dose continuous to
conjunctiva

22. ORTHOKERATOLOGY (obsolete
concept)
Believe to mould cornea & control high
myopia / astigmatism
RGP with progressive flat fitting
DIAGNOSTIC USE
Fundoscopy
Gonioscopy
Applanation tonometry
A-scan biometry

23. RESEARCH
Corneal temp. measurement

24. CONTRAINDICATIONS
OCULAR PATHOLOGIES
 Blepharitis
 Chalazion / stye
 Conjunctivitis
 Large pterygium / pinguecula
 Chronic hyperemia

25. OCULAR PATHOLOGIES
Pannus
Corneal anesthesia
Tear film abnormalities
Epithelial dystrophies
Scleritis,
Episcleratis
Iritis
CONTRAINDICATIONS

26. CONTRAINDICATIONS
SYSTEMIC DISORDERS
Diabetes
Oral contraceptive use
Pregnancy
Perimenopausal
ALLERGIES
Contact dermatitis
Asthma
Atrophic rhinitis

27. OCCUPATIONAL HAZZARD
Smoky, dusty hot environment
Chemical fumes & irritants
High altitude flyers
Construction worker / automobile
mechanics.
CONTRAINDICATIONS

28. CONTRAINDICATIONS
OTHER
Poor general health
Clumsy patient
Low hygienic standards
Old patient with low motivation
Arthritis

29. ADVANTAGE
No peripheral aberration
No chromatic aberration
Prism distortion can be controlled
Less minification / magnification
Astigmatism can controlled
No fogging
Increases field of vision
Cosmetically more pleasant

30. DISADVANTAGE
Problem for old / very young patient
Require a lot care
Supervision required
Rides low
Costly

31. CLASSIFICATION
ANATOMICAL POSITION
I. Scleral contact lens
II. Semi-scleral contact lens
III. Corneal contact lens
NATURE OF LENS MATERIAL
I. Rigid non-gas permeable/hard C.L.
(PMMA)
II. Rigid gas permeable/semi-soft C.L.
(CAB)
III. Soft C.L. (HEMA)

32. MODE OF WEAR
I. Daily wear
II. Extended wear
III. Disposable
 PURPOSE OF USE
I. Optical
II. Therapeutic
III. Cosmetic
CLASSIFICATION

33. HARD CONTACT LENS
(RIGID NON-GAS PERMEABLE LENS)
 Made of PMMA.
 Confirm to the cornea.
 ADVANTAGE
Light in weigh
High optical quality
Non toxic
Easy to manufacture

34. HARD CONTACT LENS
(RIGID NON-GAS PERMEABLE LENS)
 DISADVANTAGE
Low wettability
Low O2 permeability (DK value = 0)
Hard
Now obsolete

35. RIGID GAS PERMIABLE LENS
(RGP) / SEMI SOFT LENS
 Initially made of Cellulose Acetate
Butyrate.
 Silicon Acrylate
 Copolymer of PMMA & Silicon containing
vinyl monomer
 Styrene
 Fluropolymers-for extended wear.
 Size- usually 9-10mm.
 Best in high myopes, astigmatism >2d,

36. SOFT CONTACT LENS
HIGH WATER CONTENT
LOW WATER
CONTENT
Up to 85 % of H2O
Made of hydrogel
HEMA
HEMA-VP LENSES
MMA-PVD LENSES
Glycidyl
methacrylate
38 – 45 % of H2O
Made of silicone
hydrogel.

37. LOW WATER
CONTENT
HIGH WATER
CONTENT
 Advantage
 Less susceptible to
environment changes
 Low protein deposition
 Ease of manufacture
 More wettable
 Compatible with all lens care
product
 Disadvantage
 Low DK
 Less flexible
 Thin lens difficult to handle
 Advantage
 Higher DK
 More flexible
 Faster restoration of
shape following
deformation.
 Disadvantage
 More fragile
 More deposit prone
 Difficult to manufacture
 Lower tensile strength
 Cannot be made too thin
SOFT CONTACT LENS

38. ADVANTAGES OF RIGID
CONTACT LENS
Better quality of vision
More durable
Correction of
astigmatism
Deposit resistance
Less of chance of
infection
Cost of lens
Less comfortable, tough

39. ADVANTAGE OF SOFT
CONTACT LENS
Very comfortable and easy to adapt
Larger & adhere more tightly to the
cornea
No spectacle blur
Doesn’t correct astigmatism

40. HYBRID RGPs
Central optical zone, formed by Rigid GP
,surrounded by peripheral soft contact lens
material.
Second generation silicone hydrogel CL,
called Duette, having highly oxygen-
permeable GP centre , surrounded by a
soft silicone hydrogel “skirt” for comfort.

41. WEAR AND REPLACEMENT SCHEDULE
DW-daily wear:
• Traditional replacement cycle> 3 months
• Monthly replacement
• Daily replacement
EW-extended wear: Allowing lenses to be
worn for 7 days/6 nights without removal.
During one night per week the eyes are free
of lenses. Weekly replaced by new lenses

42. WEAR AND REPLACEMENT SCHEDULE
FW-Flexible wear: Compromise
between DW & EW. Depending upon
the demand of the patient to once a
while sleep in lenses

44. TERMINOLOGY USED FOR C.L.
TERM SYMBOL ALTERNATE TERM / ALTERNATE NAME
BOZR
(Back optical
zone radius)
ro
BC-Base curve
BCOR-back central optical radius
PCCR-posterior central curve radius
BOZD
(Back optical
zone diameter)
Ɵ 0
BCOZ-back central optic diameter
POZD-posterior optical zone diameter
OZ-optic zone
BPR
(Back peripheral
radius)
r1 , r2
BPOR- back peripheral optic radius
PCR-peripheral curve radius
BPZD
(Back peripheral
zone diameter)
Ɵ1 , Ɵ2
BPOD-back peripheral optic radius
PCD-peripheral curve radius
TD
(Total diameter) ƟT
OS-overall size
OD-overall diameter

45. CONTACT LENS FITTING
PRE-FIT CONSULTATION
 Complete history
 Detailed eye examination
KERATOMETRIC METHOD
 Pupil diameter [with IPD scale] is
measured.
 HVID is measured.
 Corneal diameter is measured.
 Radius of curvature is measured with a
keratometer.

46. KERATOMETRIC METHOD
BASE CURVE, back surface of lens.
Rest on cornea responsible for good fit.
Long radius of curvature – flatter base curve.
TD depends upon lid diameter & corneal
diameter OR HVID.
Optical zone should be at least 7 mm.
Posterior surface – Aspheric.
Anterior surface –convex with power.
CONTACT LENS FITTING

47. TRIAL LENS METHOD
Various lens from trial set tried until
appropriate B.C. achieved.
Very tedious and cumbersome
A large trial set has to be maintained
INVENTORY FITTING METHOD
Combination of both above
More time efficient and more convenient to
patient.
CONTACT LENS FITTING

48. FACTORS TO BE KEEP IN MIND
The total diameter should 1-1.5 mm greater
than HVID.
BC should be 0.3-0.6 mm flatter than the
flattest k reading.
DETERMINATION OF LENS POWER
• Spherical power + ½ cylindrical power [ if
cyl is b/w 0.5D to 2.00D ]
• If cyl is < 0.5D Drop cylinder.
• If cyl is > 2.00D , go for toric CL.

49.  Lens coverage-uniform
 Movement <0.5 mm
 Fluctuating vision clears on
blinking
 Progressive discomfort on
wearing
 Circumciliary congestion
 Edge indentation of limbus
 Retinoscopic image is fuzzy
 To correct this-
 Increase B.C. by 0.2-0.3
mm
SIGN OF TIGHT FIT

50. SIGN OF LOOSE FIT
 Poor centration
 Movement >1 mm
 Variable vision blurs on
blinking
 Edges stand off , ejection
of lens
 Retinoscopic image blur on
blinking
 To correct this-
 Increase T.D. by 0.5-1 mm
 Decrease B.C. by 0.2-0.3
mm

51.  After fitting ½ hour to 1 hour should be
given for subside reflex lacrimation.
 TOTAL PUPILLARY CAPTURE
should be.
 Movement of lens- opposite the
movement of eye
 On blinking lens should move upward.
CONTACT LENS FITTING

52. Schematic flow chart of soft contact lens fitting procedure
2. Slit lamp examination
-Corneal coverage
-Edge alignment
-Primary gaze movement
-Centration
-Push-up test
1. Insert trial lens
symptom
-comfort
-visual
Assessment of initial fit
-vision assessment
-visual acuity
-over refraction
Sub-optimal
result

53. SPECIAL CONTACT LENS
COSMETIC CONTACT LENS
1. TINTED LENS-
 Can be opaque OR transparent
 Used for cosmetic purpose
2. PAINTED LENS-
 Painted with pigment to stimulate iris
 Useful in occlusion therapy, disfigured
cornea, vision-disturbing conditions such
as albinism, aniridia , iris coloboma.

54. TYPES OF COSMETIC
LENSES
A. Iris painted with clear pupil [
Albinotic lens]
B. Black pupil and iris painted
C. Pupil painted
DISADVANTAGE-
Toxic effect
Corneal edema

55. CONTACT LENS FOR COLOUR
BLINDNESS
Using customize filters to change the
wavelength of each color.
Example- X-Chrome lens
Golden yellow lens

56. GOOGLE CONTACT LENS
 Google Contact Lens is a smart contact
lens project announced by google on 16
January 2014.
 The project aims to assist people with
diabetes by constantly measuring the
glucose levels in their tears.

58. GOOGLE CONTACT LENS
CONTENT
THE LENS CONTAINS:
 Soft contact lens:
Encapsulates electronic signals
 Sensors:
Detects glucose in tears
 Chip & Antenna:
Receives power and sends information

59. MISCELLANEOUS
 KERATOPHAKIA-
- High power lens implanted
inside corneal stroma.
 EPIKERATOPHAKIA-
- High power lens implanted in
corneal epithelium.
 KERATOMILEUSIS-
- Corneal sculpting to correct
refractive error.

60. HYPER OSMOTIC CONTACT LENS
A NEW TREATMENT MODALITY FOR
CORNEAL EDEMA

61. CORNEAL EDEMA
 Incidence: 2,000,000 new patients
annually .
 Causes
 Cataract surgery,
 Trauma,
 Infection,
 or secondary to a genetic defect in the corneal
endothelium.
 To date, there is no effective treatment for corneal
edema besides transplant from a human donor.
HYPER OSMOTIC CONTACT LENS

62. Optical performance is
diminished because:
 Shape and size of epithelial cells change
to close the gap created by the destroyed
cells.
The light-bending properties of the
endothelial cells changed.
 The excess fluid in stroma scatters
incoming light
  Reduces the ability of the cornea to
focus the light properly.
HYPER OSMOTIC CONTACT LENS

63. HYPER CL
 It is a hyperosmotic contact lens act as
a therapeutic soft contact lens with
unique capability of increasing eye
drops contact time
 Improve vision and facilitate corneal
healing
 And also proven to relieve corneal
edema.

64.  It enables extraction of fluid from the
corneal stroma, combined with
increased evaporation over the lens
surface.
 It is disposable and reusable up to two
weeks.
HYPER CL

65. The dual base
curve combined
with the groove and
the holes inside the
lens creates a
micro-environment
above the center of
cornea that holds
fluid with high ionic
concentration and
thereby absorbs
HYPER CL

66. HYPER CL DESIGN
 The Hyper-CL™ design includes
the following characteristics :
 1) Two different base
curves, which create a
tear reservoir.
 2) A peripheral groove including
4-16 fenestrations,
which increase tear
exchange and accessibility.

67.  The application of hyper osmotic drops
result in extraction of fluids from the
cornea, reducing corneal edema
OPERATION PRINCIPLE

68. INDICATION FOR USE
 Therapeutic use in Acute or chronic
ocular pathologies such as corneal
erosions,entropion,corneal edema &
corneal dystrophies.
 In post-surgical conditions resulting from
cataract extraction and corneal surgery.
 It can provide optical correction during
the healing process if required.

69. CONTRAINDICATIONS
 Any eye disease, injury, or abnormality
that affects the cornea, conjunctiva, or
eyelids, Dry eye disease .
 Any systemic disease (exaggerated by
wearing contact lenses).
 Patients unable to follow lens care
regimen or unable to obtain assistance
to do so.
 Allergic to lens material

70. HYPER CL TREATMENT MODALITIES
 To treat corneal edema awaiting
corneal transplantation or patients
unsuitable for corneal transplantation.
 As Drug delivery contact lens
 Miniscleral lens for ocular surface
problems.

72. Acknowledgements
 Dr. Anju Singh, Senior Resident,
Department Of Ophthalmology, AIIMS
Jodhpur
 Mr. Raghuveer Singh Udawat, Senior
Optometrist, Department Of
Ophthalmology, AIIMS Jodhpur
 Mr. Sampat Choudhary, Optometrist,
Department Of Ophthalmology, AIIMS
Jodhpur