Scleral lenses

BY:

NOOR MUNIRAH BINTI AWANG ABU BAKAR

OPTOMETRISTMOC: O-0869

SCLERAL LENS

OUTLINES

Scleral LensTerminology AnatomyHistoryIndicationsDesignLens fittingAdverse eventsPatient complianceFuture hope

Scleral Lens

Also known as: Haptic lens‘haptic’ = sense of touch

A large diameter rigid contact lens that cover the entire surface & rest on sclera. Diameter: 15.0mm to 25.0mm

Minimum or no contact on the cornea

Terminology

Ocular Anterior Anatomy

• Average corneal diameter is 11.8mm

•The maximum diameter a scleral lens can have is 24mm

History

When it starts?

Scleral lens is used to fit on corneal diseases (irregular corneas)

Two forms of manufacturing lens(a) Spin cast - mold(b) Lathe cut – custom made

Scleral lenses are lathe cut High cost making it unpopular

Why is Scleral Lens not popular?

Expensive Large lens diameter Difficult to fit Fragile Lack of expertise to fit Complications when patient wear it

overnight

Indications

Indications

1. Vision Improvement

Mainly for corneal ectasia cases Primary : Keratoconus, keratoglobus, PMD Secondary : Post refractive surgery (LASIK,LASEK,

PRK) Other conditions: post trauma, corneal scar due to

infection To restore and improve vision

Indications

2. Corneal protection In 2 conditions:

Severe ocular disease (Sjogren, Steven Johnson, Graft versus host dx)

Incomplete lid closure (eyelid coloboma, ectropion, exophthalmos, nerve palsies)

Help by reducing corneal exposure to air (not to close the eye)

Benefits: To relieve symptoms of pain & discomfort Keep ocular surface moist in severe dry eyes by fluid

reservoir retention Slow the progression of corneal disease and delay the

need for surgery Decrease risk of scarring

Indications

3. Cosmetic In prosthetic eye (not widely use in Malaysia due to

its cost) Full ocular prostheses Partially prostheses

Use on: aniridia (reduce glaring), albinism, trauma,nanophthalmos

4. Sport More secured – reduce risk of loss Provides stable vision and comfort

Indications

5. Drug delivery Scleral lens has tear reservoir Instill drug onto bowl of scleral lens RGP is not suitable for drug delivery, due to lens

movement

6. Normal eyes Very common in other country Corneal lens cannot fit well It gives less complication

Design of scleral lens


1. Optical zone Minimal/not contact with cornea (RGP: contact) Large size (RGP: smaller) Give optical effect Surface:

Anterior surface: Aspheric design to reduce photophobia and aberration

Posterior surface: Same shape as cornea Sagittal height of scleral lens is higher than RGP sagittal

height Available in toric (but not available in Malaysia)


2. Transitional zone Only scleral lens has transitional zone Connect sclera and sclera It set the sagittal height

Changing sagittal height means change the transitional zone (flatter or steeper)

Depends on the shape of the sclera The transitional zone for small diameter ScCL may rest on

limbal area, not for larger diameter ScCL. Range of transition zone: 0.5mm to 2.0mm.


2. Transitional zone Scleral shape

Referring to cornea, limbus and sclera Affect the ScCL fitting

Involve the transitional and landing zone The sclera can be evaluated using:

Pentacam Anterior segment OCT

Type of limbal profile:1. Gradual convex2. Gradual tangential (common)3. Convex concave4. Marked convex (common)5. Marked tangential

1 2 3 4 5


2. Transitional zone Limbal angle and scleral angle

What: This is angle between iris & cornea Temporal angle larger than nasal angle (T≠N) ScCL easily decentred to the nasal However, it would not affect vision because the optical zone

is large.


3. Landing zone (Haptic zone) Area of ScCL that rest on the sclera Important to know:

Size of landing zone Angle of landing zone

Landing zone as back surface toric: change the thickness at one side

Can make peripheral toric by thinning the edge like prism ballast.

Increase diameter of landing zone, make it more comfortable to wear as less movement produced

Scleral lens fitting


4 steps approach


1. Optical/ Clearance zone diameter Optical zone important to provide good optical

outcome and corneal clearanceClearance zone = optical zone + transition

zoneUsually 0.2mm larger than HVIDSize depends on lens designsCan be altered to improve corneal and limbal

clearance

Scleral lens fitting-Lens insertion


2. Central and limbal clearanceUp to 600 microns of corneal clearance can be easily

achieved if needed centrally.Clearance of 200–300 microns is usually considered

sufficient, but this can easily go up to 500 microns if desired with the end stage large diameter lenses.

The terms “flat” and “steep” are substituted with increase or decrease in sagittal height instead. Increasing the sagittal height of the lens causes the lens to “lift” off the

eye, increasing the clearance or vault of the lens.Sagittal depth differs with the condition:

Ectasia needs larger than post-corneal grafts Ocular surface disease management requires large sagittal height


Central and limbal clearance evaluation Start with low sagittal height and gradually increase height to desired

clearance A green fluorescein pattern will be visible. Use a thin optical section with brightest illumination setting at a 45 degree

angle If CCT known, compare corneal thickness to tear layer thickness to estimate

clearance If CCT not know, assume a 530micron central cornea and 650 micron at

periphery (Doughty 2000) and compare to the slit.


Limbal clearance Complete and generous limbal clearance is necessary

to ensure tear circulation and prevent erosive damage to the limbal epithelial cells.

If very little fluorescein observed in the limbal area of the lens, then the lens is too small and should select a larger diameter. Scleral lens with inadequate limbal clearance

Scleral lens with complete limbal clearance


3. Landing zone alignment The landing zone should rest evenly on the scleral conjunctiva with

the edge appearing just above the conjunctival epithelium.

The lens should not move with blinking. Moving lens cause discomfort to the patient. Can correct by tightening the landing zone.

No fluorescein will be visible under a well-fit landing zone except at the edge. A ring of bearing on the inner part of the landing zone indicates a flat

landing zone A ring of bearing on the outer part of the landing zone indicates a steep

landing zone Increasing the size of the landing zone relieves pressure if needed.


4. Lens edge lift Assess lens edge lift after 30 minutes of lens installation during

fitting process. Also assess lens edge after 3-4 hours of lens wear.

Too much edge lift : Cause lens awareness and discomfort Action: Decrease the edge lift by changing the landing zone angle or by

choosing a smaller landing zone radius of curvature. Low edge lifts:

Leave a full or partial impingement ring on the conjunctiva after lens removal Two easy methods

Observe the edge lift with white light & how much it “sinks” into the conjunctiva

Push-in method -preferred if the lens showed some mobility Remove lens and evaluate surface with fluorescein staining

Adverse events

Adverse events

Adverse events

Patient compliance

Patient compliance:1. Hygiene

Cleaning kit same as RGP, must using protein cleaner. If deposit on lens present, first see Giant papillary

Conjunctivitis.

2. Sleeping with Scleral CL Pt love to wear lens overnight. Advice patient not to wear scleral lens extendedly to

avoid complications.

Future Scleral Lens

Would you consider scleral lens in future? YES.

Good alternative for irregular cornea Less complications Better corneal health

Future Scleral Lens

Thank You

Healthcare

Scleral lenses