Post on 10-Apr-2017
GREESHMA G
MPHIL FIRST YEAR
A GLIMPSE THROUGH SCLERAL CONTACT LENSES
SCLERAL LENS
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WHAT IS PROSE????
• PROSE- Prosthetic replacement of ocular surface ecosystem
• A PROSE device is a Scleral Contact Lens intended restore vision, support healing, reduce symptoms and improve quality of life for patients suffering with complex corneal disease
ABOUT SCLERAL LENS
• Scleral contact lenses (Haptic lenses) are large diameter gas permeable lenses which completely cover the cornea and rests on the sclera
• Creates a liquid bandage over the ocular surface
• Masks regular and irregular astigmatism
• Useful for fragile and diseased corneas and for dry eyes
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EVOLUTION OF SCLERAL LENSES
• First made 125 years ago
• Smaller GP lenses and soft lenses
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TERMINOLOGY
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WHEN WE WILL GO FOR SCLERAL LENSES??
INDICATIONS OF SCLERAL LENSES
Corneal ectasia Corneal scars
Corneal degenerations or
dystrophies
High refractive corrective
errors
Cosmesis and sports
• keratoconus• keratoglobus• Pellucid
marginal degeneration
• Post LASIK• Post LASEK• Post PRK• Post RK• Post Trauma
• Herpex simples virus
• Terrien’s marginal degeneration
• Salzmann’s nodular degeneration
• Hyperopia• Myopia• High
astigmatism
• Aniridia• Albinism• Diving• Water
skiing
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ADVANTAGES OF PROSE
• Fluid reservoir- Supports healing and reduces symptoms• Protecting and shielding the cornea and conjunctiva• Improves stability• Optical neutralization of irregular astigmatism
ANATOMY
• Conjunctiva is the landing plane for scleral lenses
• Conjunctiva: Structure less tissue
• Sclera constitutes the shape of the anterior eye beyond the corneal borders
• Scleral shape is not equal in all meridians
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PREREQUISITES BEFORE FITTING
• Observe eye shape: lateral positions• Corneal topography: shape of cornea • Initial trial set• ASOCT
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SCLERAL LENS FITTING PRINCIPLES
FITTING ASPECTS• Total lens diameter and optical zone diameter
• Establishing the central and limbal clearance
• Appropriate landing zone alignment
• Adequate lens edge
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SCLERAL LENS FIT ASSESSMENT GUIDE
1. Front surface of lens
2. Center thickness (CT)
3. Clearance(1/2 of CT)
4. Corneal thickness
1.Amy Dinardo etal; Introducing scleral lens fit assessment guide based on tear layer thickness; Scleral lens fitting scales; GSLS; 2014;Ferris state university; WWW.ferris.edu
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VAULT OF SCLERAL LENSES
• Fluid reservoir
• Increasing diameter increases vault
• Vault reduces in short and long term scleral lens settling
• Central clearance: 50 to 300 microns
• No statistical correlation between vault and visual acuity
• Trial : Minimum of 200 microns vault
1. George W Denaeyer; Scleral lens fitting success, Improve your scleral lens fitting success; CL spectrum; vol 29; Nov 2014; 22-25
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Higher vault Limbal bearing nasally visible in the
fluorescein pattern
Mini-scleral lens with inadequate
vault over corneal graft optic section
HAPTIC OF SCLERAL LENSES
Edge lift
• Scleral toricity
• Flatter lens fit can cause edge lift
• Edge lift can induce bubbles
• Causes discomfort
• Symblepharon
• If EL is present then switch to small diameter lens or use a Toric back surface haptic
Impingement
• Steeper fit leads to blanching peripherally
• Flatter lens seals mid periphery
• Paralimbal injection
• Difficult to remove
• Avoid over pushing of lens
• Discomfort
• Reduces wearing time
• Neo vascularization
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IMPINGEMENT
• Long term settling occurs secondary to adaptive changes in bulbar conjunctiva
• Bearing on ocular surface induces staining
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Impingement ring
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Local blanching underneath thelanding zone of a large scleral lens
Good haptic conjunctival fit
Circum corneal blanching
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Scleral lens periphery impinging in a pingecula causing inflammation and hypertrophy
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Irregular corneas
Preliminary examination
Prose device fitting
Optimum fit
Three hour Six hour
Day 1
Day 3Day 2
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INSERTION OF THE DEVICE
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REMOVAL
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HISTORY TAKING
• Vision with Scleral lenses
• Comfort
• Wearing hours
• How often they changes saline- SJS patients
SLIT LAMP EXAMINATION• Corneal clearance
• Lens periphery- edge lift
• Blanching
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CARE AND MAINTENANCE
• Not like Soft contact lenses or RGP lenses
• GP PLUS solution
• MPS crystal Solution
• Unpreserved Saline
• Sterile needle gauge
SCLERAL LENS FIT SUCCESS
• Successful fit: Patient comfortable with no or minimal signs of staining or injection after removal
• Best time for observing early complication is three to six hours after wear
• Look how lens sits on eye
Impingement – conjunctival staining
Compression- discomfort
Vault contact – staining
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ACKNOWLEGMENT
• Pic Courtesy- A Guide to scleral lens fitting_Eef Vanderworp
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THANK YOU