Managing Complex Irregular Corneas with Scleral Contact Lenses

Fernando Auza, O.D. Visionary OphthalmologyLecture Series 11February 20, 2011

Scleral LensesBeyond the Borders

Large diameter contact lenses that have their resting point beyond the corneal borders

Believed to be among the best vision correction intervention among contact lenses for irregular corneas

Decrease the risk for corneal scarring.

Terminology

Alternative Names

Diameter Bearing Tear Reservoir

Corneal 8.0 to 12.5mm

Cornea No Tear Reservoir

Corneo-Scleral

Corneal-Limbal

Semi-Scleral

Limbal

12.5 to 15.omm

Cornea and Sclera

Limited tear reservoir

Full Sleral Haptic Miniscleral 15.0-18.0

Large Scleral

18.0 – 25.0

Sclera Tear reservoir directly related to size of haptic

Indications

Vision improvement Corneal protection Cosmesis

1. Vision Improvement – Main indication

Primary corneal ectasias - largest segment Keratoconus Keratoglobus Pellucid Marginal Degeneration

Secondary corneal ectasias/Post-surgical corneas Post-LASIK and post-PRK Corneal grafts Irregular corneas due to trauma

2. Corneal Protection

Severe ocular surface disease Sjogren’s syndrome Persistent epithelial corneal

defects Steven’s Johnson Syndrome Graft Versus Host Disease Cicatricial pemphogoid Neurotrophic Ulcers

Incomplete lid closure Eyelid coloboma Exophthalmus Ectropion Nerve palsies

3. Cosmesis

Hand painted scleral lenses Aniridia Albinism Nanophthalmus Trauma

Scleral Lenses Vs Regular GP’s Scleral lenses are very comfortable Reduce risk of scaring -CLEK study determined risk

factors for corneal scaring in Keratoconus Corneal curvature > 52.00D Contact lens wear Marked corneal staining Patient age less than 20 years

Scleral lenses have large optical Zones and center better than corneal GP’s

Scleral lenses and Surgery

The National Keratoconus Foundation estimated that 15-20% of keratoconus patient will eventually undergo surgery

Many post-PK patients still need CL’s to restore vision A study by Smiddy et al (1988) found that 69 percent

of patient who were referred for keratoplasty could be succesfully fitted with contact lenses prolonging the need for surgery Keratoconus. Contact lens or keratoplasty? Ophthalmology. 1988

Apr;95(4):487-92. Evaluate all contact lens options including scleral lenses before

considering surgery

Keratoconus. Contact lens or keratoplasty? Ophthalmology. 1988 Apr;95(4):487-92. 190 eyes with keratoconus, all referred for

keratoplasty after CL’s had no longer been successfull

25(13%) could not be fitted 165(87%) - successfully fitted 51(31% of 165) -PK after an average of 38.4

months of CL wear 114(69%)- no PK over an average follow up

time of 63 months

Anterior Ocular Anatomy

Average corneal diameter of 11.8mm

24mm -the maximum diameter a scleral lens can have

7.5mm

7.0mm

5.5mm

6.5mm

Limbal and Anterior Scleral Shape

Corneo-limbal-scleral transition is often tangential rather than curved

Limbal profiles

Two most commonly occuring limbal profiles Profile 2 (gradual-tangential) followed by profile 3 (marked

–convex) Die Kontaklinse by Rott-Muff (2001)

Daniel Meier/die Kontaktlinse

Limbal profiles

Study of 46 eyes concluded an even distribution of gradual vs. marked transitions Van der Worp E, (2010b) Exploring Beyond the Corneal Borders, Contact Lens Spectrum; 6,

26-32

Contact Lens Spectrum, June 2010

Limbal and Scleral Angles; the Scleral Shape Study 96 eyes normal eyes OCT measurements in eight directions Concluded:

Corneal-limbal zone – straigh in most cases Anterior scleral shape – tangential in most cases Within limbal zone – difference in angles are small (on average

1.8 degrees or 108microns) Within scleral zone – difference in angles larger (on average by

6.6 degrees or 400microns)

Simmulated Scleral Topography based on the Scleral Shape Study

Scleral Lens Design

1. The optic zone

2. The transitional zone

3. The landing zone

Contact Lens Spectrum; Dec. 2009

The Haptic/Landing Zone

Area in touch with anterior ocular surface Ideally mimics the shape of the sclera Some designs specify landing zone radius of

curvature, others as landing angles. Size of landing zone can be increased to

improve comfort and stability

Fitting Spherical Scleral Lenses – Four Step Approach

1. Chose diameter

2. Establish central and limbal clearance

3. Landing zone alignment

4. Adequate edge lift

Chosing the Diameter Depends on anterior ocular sagittal height Factors affecting sagittal height evaluate:

Corneal curvature Asphericity HVID Shape of anterior sclera – difficult do evalluate

Common diameter used in the US is 15-18mm

Optical/Clearance Zone Diameter Optical zone important to provide good optical

outcome and corneal clearance Clearance zone = optical zone + transition zone

Usually 0.2mm larger than HVID Size depends on lens designs Can be altered to improve corneal and limbal

clearance

Clearance

Up to 600 microns of corneal clearance can be easily achieved if needed centraly

Large or small sagittal height should be used instead of steep or flat

Minimum of 100microns is the desired at any place

Sagittal depth differs with the condition Ectasia needs less than post-corneal grafts Ocular surface disease management requires

large sagittal height

Evaluating corneal clearance

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

cornea and compare to the slit

LS11 Inmages\LS slit scan.AVI

Evaluating Central Corneal Clearance

50microns

250microns

500microns

Evaluating peripheral corneal clearance

Ideally no touch and limbal clearance should be obtained

If clearance is < 20microns, clinician may not be able to indentify underlying fluorescein band – look for staining

Trace limbal touch

Limbal clearance

Limbal Clearance

Avoid mechanical pressure in the limbal area If good central clearance achieved but limbal

clearance is absent change the limbal clearance zone Flattening BC – reduces pressure Change transition zone angle Increase OZ diameter

Landing Zone Fit

Aligning the periphery of the lens with the scleral shape

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

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

Two easy methods Push-in method (video) Remove lens and evaluate surface with

fluorescein staining

LS11 Inmages\LS edge lift.AVI

Conjunctival Impingement

Courtesy of Cristine Sindt, OD, FAAO

Conjunctival Blanching

JC, 16y/o male presents for CEE Patient interested in contact lenses Plays football and lacrosse MR

OD: -1.00-3.75x005 20/20 OS: -0.25-2.25x003 20/20

Keratometry OD: 40.9/44.8@095 OS: 41.3/44.7@090

HVID: 12.0mm

Soft Contact Lens Trial

Freq 55 Toric/8.4 OD: -1.00-3.75x180 20/25 Slow OS: Plano-2.25x180 20/20-2 Excessive movement >3mm, unstable rotation OU Unstable VA

Soft Lens Toric OD: -1.50-2.75x180 20/20-2 OS: Plano – 2.25x180 20/20-2 Unstable rotation and Vision

Discussed Regular GP’s and Scleral Lenses Jupiter 15.6

OD: 7.11/-9.00/15.6mm/Standard periphery Great fit, 20/20

OS: 7.18/-8.00/15.6mm/12.75 Int.Zone/14.25 Peripheral zone - 20/25 – unstable Overall corneal and limbal clearance Loose peripheral fit and excessive edge lift Excessive movement and unstable vision

OS: 7.18/-8.00/15.6/12.25Int.Zone/13.75 peripheral zone – 20//20 (Stable)

ID, 43y/o female presents for corneal evaluation Blurry vision with Specs and unable to wear CL’s OcHx: Keratoconus OU, s/p PK OU 20 years ago MR; OD: -13.75+3.00x117 20/70

OS: -10.00+500x046 20/100 Dx:

S/P PK OU Recurrent Keratoconus

Plan: PK OS Contact Lens OD

Rose K2 IC 5.82/11.20mm Lens flat centrally Manufacture unable to produce a steeper

curve

Jupiter 16.0 /6.25mm/54.00D/-9.50 20/25+ Central Touch/Good limbal clearance/ loose

peripheral fit (Video) Ordered

Jupiter 16.0/6.25/-12.25/9.0 OZ/Steeper tertiary curves (raise SH by 110microns)

Obtained 100microns of central clearance, limbal clearance and adequate scleral landing

VA 20/20-1 WT:10hrs/day comfortably

LB, 28y/o female

Blurry vision OU, spectacles do not help. OcHx: RK OU and LASIK OU four times VAsc: OD 20/80 OS:20/80 MR:

OD -5.50+500x175 20/70-1 OS:-150+2.25x005 20/60-2

Cornea has 6 radial and 6 radial incisions OU

OD: RSS 9.92/7.67/10.5 OS: RSS 9.62/7.67/10.5 Both lenses decentered up and temporal Poor vision and excessive inferior lift

OD:Jupiter 15.6/7.18/-7.00 OR -17.00 20/30

453microns

300microns

6.5mm

OS: 7.03/-8.00/15.6 OR -24.00 20/50

Ordered

OD: Jupiter 7.03/16.6/-14.75/8.6OZ/Steeper Transition zone

OS: Jupiter 7.50/16.6/-5.00/8.6 OZ/Steeper transition zone

Larger diameter and steeper transition zone will raise sagittal depth corneal periphery keeping same corneal clearance

Scleral lenses can help delay surgery Most difficult corneas can be successfully

fitted with scleral lenses http://commons.pacificu.edu/mono/4/ Thank you!