corneal topography corneal cross linking pediatric and presbyopic contact lens

MIDRA KHANAIJAZ ALI SADHAYOSAHIBA SOLANGIQURATULAIN MARYAMTEHSEEN JAVAID

EDGE LIFTCORNEAL TOPOGRAPHY

CORNEAL CROSS LINKINGPAEDIATRIC CONTACT LENS

PRESBYOPIC CONTACT LENSES

Presented By:

Tuesday, May 2, 2023 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.

EDGE LIFT


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.

EDGE CLEARANCE


Refers to study of the shape of corneal surface

CORNEAL TOPOGRAPHY

USES OF CORNEAL TOPOGRAPHY

Keratoconus causes thinning i.e PMD, Keratoglobus.

Corneal scars or opacitiesFitting contact lensesIrregular astigmatism following

corneal transplantationMonitoring the disease progression

05/02/2023 6


BAUSCH & LOMB KERATOMETER

JAVAL-SCHIOTZ KERATOMETER

PLACIDO DISK


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

9PENTACAM GROSS PENTACAM HR GROSS

OCULUS PENTACAM AXL

COLOR CODINGHot Colors

Red and OrangeRepresents the steepness of Cornea

Cool Colors..Yellow represent NormalGreen represent Flatness of cornea


ELEVATION FRONT


ELEVATION BACK


CURVATURE


CORNEAL THICKNESS

The lens loses elasticity from the aging process called Presbyopia.

WHAT IS PRESBYOPIA?

Correcting Presbyopia with contact lenses can be done in several different ways:

Reading glasses over contact lenses MonovisionPresbyopic contact lenses

Correcting Presbyopia

Presbyopic contact lenses

Alternating vision CL Simultaneous vision CL

Segmented annular

Aspheric diffractive


PAEDIATRIC CONTACT LENS

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 AGEBaby 0-12 months old

Toddler 1-3 years oldPre School 3-5 years

Grade-schooler 5-12 years oldTeen 12-18 years old

Young adult 18-21 years old

Aphakia High Myopia High hyperopia Irregular

Astigmatism Anisometropia

NYSTAGMUS Ambloypia Aniridia

REFRACTIVE AND THERAPEUTIC CORRECTION

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

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

CL FITTING PROCESS4. 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

CL FITTING PROCESS6. 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.

CL FITTING-PARAMETERSAverage Power Needed for the Aphakic EyeAge (month)

BOZR (mm)

TD (mm) Power (D)

1 7.00 12.00 +352 7.20 12.50 +323 7.50 13.00 +306 7.80 13.50 +2512-24 8.10 13.50 +20 to 26

Corneal Curvature

CL FITTING- CONSIDERATIONConsiderations Specific to the Infant

maximum oxygen permeabilityexpanded powerssteeper base curvessmaller overall diametersease in handling and durability reproducibleability to use medication

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

careUnable to understand instruction (infants)

Alternative: voice, touch & smellAnxiety about the procedures (for toddlers)

Resisting during procedures


CORNEAL CROSS LINKING


Progressive corneal steepening and thinning in the absence of surgery.

KERATOCONUS


WHO IS NOT AT A RISK?

SMOKER CHILDHOOD

DIABETIC

31

Contact lensesCXLCorneal ring segment inserts (Intacs)Corneal transplants

TRADITIONAL TREATMENTS

http://en.wikipedia.org/wiki/Image:KC-lens.jpg

http://en.wikipedia.org/wiki/Image:Intacsonfinger2.jpg

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

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

Keratoconus.PMD.Post operative surgery (Lasik)

INDICATION

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

CONTRAINDICATIONS

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

Riboflavin(Vitamin B2)UVA light.

CXL UVA + RIBOFLAVIN

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

TECHNIQUES

Installing anesthetic drop.Epithelium on/0ffRiboflavin drop 30 min.UVA for 30 min.Antibiotic drop installation.BCL inserted.

People see better w/in 5-6 days

PROCEDURE

EPITHELIUM ON


EPITHELIUM OFF

PainHazy Cornea.Ulceration.Infection.Corneal Edema.Keratitis.

COMPLICATIONS


Maximum analysis for 6 years Improvement in UCVA 1-3 lines Improvement in BCVA 1-2 linesReduce myopia 0.4-1.14 DiopterReduce astigmatism 0.93 DiopterPost-Operative regression of keratocouns in 70%

cases

RESULT


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?


THANK YOU

corneal topography corneal cross linking pediatric and presbyopic contact lens

Healthcare