Final Year Student Of Optometry at ISRA School Of Optometry All Rights Reserved

1. MIDRA KHAN
AIJAZ ALI SADHAYO
SAHIBA SOLANGI
QURATULAIN MARYAM
TEHSEEN JAVAID
EDGE LIFT
CORNEAL TOPOGRAPHY
CORNEAL CROSS LINKING
PAEDIATRIC CONTACT LENS
PRESBYOPIC CONTACT LENSES
Presented By:

2.  The concept of edge lift is related to the lens design of the
eye.
 Series of curve that lead into the edge shape.
 AXIAL EDGE LIFT:
 Peripheral clearance due to the flatting of the peripheral curve
relative to the back optic zone radius.
 Axial distance from edge of lens to imaginary surface formed by
extension of base curve.
 RADIAL EDGE LIFT:
 Peripheral clearance due to the flatting of the peripheral curve
relative to the back optic zone radius.
 Radial distance from edge of lens to imaginary surface formed by
extension of base curve.
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EDGE LIFT

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4.  The distance between the posterior edge level of a RGP lens
and the cornea.
 TOO LITTLE EDGE CLEARANCE:
 Inadequate tear exchange.
 Poor lens movement.
 Pressure at the lens edge and arcuate staining.
 Difficulty with lens removal and lens adhesion
 TOOMUCH EDGE CLEARANCE:
 Inadequate tear exchange.
 Poor lens movement.
 Bubbles under the lens periphery which cause trothing or dimpling.
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EDGE CLEARANCE

5. Refers to study of the shape of corneal
surface
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CORNEAL TOPOGRAPHY

6. USES OF CORNEAL TOPOGRAPHY
 Keratoconus causes thinning i.e PMD,
Keratoglobus.
 Corneal scars or opacities
 Fitting contact lenses
 Irregular astigmatism following corneal
transplantation
 Monitoring the disease progression
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BAUSCH & LOMB
KERATOMETER
JAVAL-SCHIOTZ
KERATOMETER
PLACIDO DISK

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Keratometry
•Measurement of
curvature
•Measures 4 points in
central 3-4 mm cornea
•Assumes cornea to be
a sphero-cylinder
•Results are difficult to
reproduce
•Subjective variations
present
Topography
•Measurement of
overall cornea
including curvature,
power, elevation,
pachymetry etc
•Can measure all the
zones of cornea
•Measures asphericity
with accuracy
•Results are repetitive
•Automated technique,
no subjective variation

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PENTACAM GROSS PENTACAM HR GROSS OCULUS PENTACAM AXL

10. COLOR CODING
Hot Colors
Red and Orange
Represents the steepness of Cornea
Cool Colors..
Yellow represent Normal
Green represent Flatness of cornea

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ELEVATION FRONT

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ELEVATION BACK

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CURVATURE

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CORNEAL THICKNESS

15. The lens loses elasticity from
the aging process called
Presbyopia.
WHAT IS PRESBYOPIA?

16.  Correcting Presbyopia with contact lenses can be done in
several different ways:
 Reading glasses over contact lenses
 Monovision
 Presbyopic contact lenses
Correcting Presbyopia

17. Presbyopic contact lenses
Alternating vision CL Simultaneous vision CL
Segmented annular Aspheric diffractive

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PAEDIATRIC CONTACT LENS

19.  Paediatrics : A branch of medical care that deals with
infants, children and adolescents, from birth up to age
of 18 (in US up to 21)
 The word paediatric is derived from two Greek words
(pais = child and iatros = healer), which means healer
of children.
 Classification by American Academy of Paediatrics:
WHO IS PAEDIATRIC?
STAGE AGE
Baby 0-12 months old
Toddler 1-3 years old
Pre School 3-5 years
Grade-schooler 5-12 years old
Teen 12-18 years old
Young adult 18-21 years old

20.  Aphakia
 High Myopia
 High hyperopia
 Irregular
Astigmatism
 Anisometropia
 NYSTAGMUS
 Ambloypia
 Aniridia
REFRACTIVE AND THERAPEUTIC CORRECTION

21. CONTACT LENS FITTING
 What age appropriate to fit contact lens?
“ by the age of eight, a child was able to handle contact lenses and
assume some degree of responsibility.”
 However, child's maturity and ability to handle contact lenses
responsibly is more important than age alone.
 Otherwise, optometrist should educate and guide parents on proper
handling of CL.
 Pre-fitting apparatus
 Contact lens fitting sets
 Retinoscope and loose lenses
 Fluorescein strips and Wratton filter
 Keratometer (optional)
 Burton Lamp
 Contact lens solution, case & cleaners

22. CL FITTING PROCESS
1. HISTORY TAKING
•Pt chief problem, ocular & health history
•Family ocular & health history
2. OCULAR EXAMINATION
•VA & refraction
•Corneal measurement: Handheld topo or Keratometry
3. CL TYPE & PARAMETER SELECTION
•Diameter: SCL: 2-3mm >HVID.; RGP :1-2mm<HVID
•Base curve: 1-2D steeper than flatter K. Initial BC can refer to Table 1
•Power: Expected age value
•Material: High Dk

23. CL FITTING PROCESS
4. CL FITTING
•Parent holds baby’s leg and arm.
•Hold pt’s upper lid with index finger & pull down pt’s lower lid with
thumb. Then, slide the lens under the upper lid and under the lower
lid with the index finger of other hand.
•While positioning & inserting lens, explain to the parent what, how
and why doing those steps. Thus, parents can apply at home.
5. CL ASSESSMENT
•Allow the lenses to settle for about 20 minutes. The ideal physical
fit: (Pentorch or Burton lamp-Fluorescein)
•can observe 2mm movement
•there is no encroachment upon the limbus (Soft CL)
•the optics are within the pupil.
•Avoid tight fitting

24. CL FITTING PROCESS
6. FOLLOW UP
•1 day: To evaluate the fitting, perform retinoscopy and stain the
cornea.
•2 to 4 weeks: For lens removal, cleaning and disinfection & teach
parents.
•Parents must be educated on how to apply lens lubricant every
morning and night.
•Advise parents to look for redness, discharge ,rubbing eyes.
7. LENS ORDER
•Add 2D or 3D for final prescription-to enhance near vision.
•RGP: Custom-made, variety of power
•Soft lens like SilSoft: Power limitation-Lenses come in 3D
increments , prescribe more plus because the infant world is up
close.

25. CL FITTING-PARAMETERS
 Average Power Needed for the Aphakic Eye
Age
(month)
BOZR
(mm)
TD (mm) Power (D)
1 7.00 12.00 +35
2 7.20 12.50 +32
3 7.50 13.00 +30
6 7.80 13.50 +25
12-24 8.10 13.50 +20 to 26
Corneal Curvature

26. CL FITTING- CONSIDERATION
 Considerations Specific to the Infant
maximum oxygen permeability
expanded powers
steeper base curves
smaller overall diameters
ease in handling and durability
reproducible
ability to use medication

27. CHALLENGE IN PAEDIATRIC CL MANAGEMENT
 Infant & toddler eye anatomy
 Small palpebral fissure
 Steeper cornea than older patient
 Higher powers than the older pt (due to shorter axial length)
 Parent time & motivation
 Time limitation
 Find difficulty on lens insertion and removal process, lens care
 Unable to understand instruction (infants)
 Alternative: voice, touch & smell
 Anxiety about the procedures (for toddlers)
 Resisting during procedures

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CORNEAL CROSS LINKING

29. Progressive corneal steepening and thinning in the absence of
surgery.
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KERATOCONUS

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WHO IS NOT AT A RISK?
SMOKER CHILDHOOD DIABETIC

31.  Contact lenses
 CXL
 Corneal ring segment inserts (Intacs)
 Corneal transplants
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TRADITIONAL TREATMENTS

32.  Corneal cross linking is a well establish technique for corneal
Ectasia such as keratoconus it is use to make the cornea
stronger. Also known as (C3-R, CCL and KXL)
CORNEAL CROSS LINKING

33.  Developed in Germany
 FDA not approved in the U.S.
 Studied since 1994 University of Dresden
 First discovered and applied in 1998.
 Use for keratoconus treatment in 2003.
 Successfully use for post lasik and PMD.
HISTORY

34. Keratoconus.
PMD.
Post operative surgery (Lasik)
INDICATION

35.  Corneal thickness less than 400micron.
 Herpectic infection.
 Concurrent information.
 Ocular serface condition
 Autoimmune disorder.
CONTRAINDICATIONS

36.  Young patients with good history expected to progress if
untreated
 Age <35 yr
 Kmax <56 D
 Pachymetry > 400 microns
 Health History Non-smoker/Non-diabetic
 Corneal signs Scissoring or Thinning
No or few Vogt’s striae
No or little scarring
 Keratoconus/Ectasia History Rapidly progressive disease At
least 3 months of topographic history preferred
IDEAL CXL CANDIDATE

37.  Riboflavin
 (Vitamin B2)
 UVA light.
CXL UVA + RIBOFLAVIN

38.  Epithelium off.
 Transepithelium.
 Accelerated cross linking.
 CXL in thin cornea.
 Lasik extra.
TECHNIQUES

39.  Installing anesthetic drop.
 Epithelium on/0ff
 Riboflavin drop 30 min.
 UVA for 30 min.
 Antibiotic drop installation.
 BCL inserted.
 People see better w/in 5-6 days
PROCEDURE

40. EPITHELIUM ON

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EPITHELIUM OFF

42. EPITHELIUM OFF

43. Pain
Hazy Cornea.
Ulceration.
Infection.
Corneal Edema.
Keratitis.
COMPLICATIONS

44.  Maximum analysis for 6 years
 Improvement in UCVA 1-3 lines
 Improvement in BCVA 1-2 lines
 Reduce myopia 0.4-1.14 Diopter
 Reduce astigmatism 0.93 Diopter
 Post-Operative regression of keratocouns in 70% cases
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RESULT

45.  Q:- Is CXL new?
 Q:- How effected CXL?
 Q:- Can CXL perform everyone with keratocouns?
 Q:-Can CXL prevent the need for corneal transplant
 Q:- How long does CXL treatment last?
 Q:- Do I have to stop wearing contact lens before having CXL
 Q:-Does CXL improve Vision?
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