© The International Association of Contact Lens Educators Special Applications of Contact Lenses E5 SAMPLE

© The International Association of Contact Lens Educators Special Applications of Contact Lenses Lecture contributors*Robert Terry, Lewis Williams, Others*** Lecture editor**Bezalel Schendowich IACLE executive editor**Lewis Williams IACLE reviewers**Nilesh Thite, Lewis Williams Lecture updated2015-Apr-14 Lecture content rechecked2015-Apr-28 * Original author(s) of lecture(s)**2014/2015 Editors and reviewers *** Ma Meredith REYES, Christopher SNYDER, David PYE, Prashant GARG, Les DONOVAN, Des FONN (Editor-in-Chief)

IACLE SPONSORS © The International Association of Contact Lens Educators Industry Supporters Previous Supporters Development and delivery of contact lens education by IACLE is supported through educational grants and in-kind contributions CIBA Vision Bausch & Lomb Allergan AMO Ocular Sciences Wesley Jessen Menicon Paragon Pilkington Barnes-Hind Aspect Vision Care Platinum SponsorSilver Sponsors Donor Sponsor

© The International Association of Contact Lens Educators SAMPLE ONLY The following slides are an excerpt from the revised IACLE Contact Lens Course lecture Special Applications of Contact Lenses E5

© The International Association of Contact Lens Educators Post-Corneal Surgery CL Fitting

© The International Association of Contact Lens Educators GP CLs are the modality of choice for post-RK fitting usually corneal shape is irregular Trial fitting essential fluorescein pattern assessment Try simple CL designs first: spherical aspherical Consider toric if necessary Orthokeratology designs (reverse geometry) may prove useful Specialized designs for RK Post-Corneal Surgery CL Fitting RK CL Selection

© The International Association of Contact Lens Educators Based on an analysis of corneal topography: pre-surgical keratometry corneal topography Based on the amount of myopia Large CL Total Diameter (TD) Post-Corneal Surgery CL Fitting CL Fitting

© The International Association of Contact Lens Educators Adequate peripheral clearance No bubbles inferiorly Good tear exchange Large optical zone extending to the corneal periphery Larger than normal axial edge clearance Post-Corneal Surgery CL Fitting CL Fitting: Desirable Features

© The International Association of Contact Lens Educators Expect to see: Central fluorescein pooling Lens decentration Bubbles beneath CL Post-Corneal Surgery CL Fitting CL Fitting Assessment

© The International Association of Contact Lens Educators Fluctuating Vision Diurnal variation Trial a flatter fitting ↑ CL centre thickness Flare & Glare ↑ BOZD ↑ lens total diameter (TD) Trial an aspheric design Post-Corneal Surgery CL Fitting Solving CL Fitting Problems

© The International Association of Contact Lens Educators Post RK Fitting: CL is decentered: superiorly & nasally Post-Corneal Surgery CL Fitting

© The International Association of Contact Lens Educators ↑ BOZD Modify peripheral curves Trial an aspheric design Add prism ballast for high-riding CLs Consider a reverse geometry design Post-Corneal Surgery CL Fitting Solving Decentration Problems - Superior

© The International Association of Contact Lens Educators ↓ CL mass lenticulation ↓ CL total diameter (TD) Use lower specific gravity (SG) material Incorporate a minus lenticular design Large BOZD with flat peripheral curves Consider a reverse geometry design Post-Corneal Surgery CL Fitting Solving Decentration Problems - Inferior

© The International Association of Contact Lens Educators Excessive change to an aspheric design Inadequate flatten/widen peripheral curves Post-Corneal Surgery CL Fitting Peripheral Clearance

© The International Association of Contact Lens Educators Significant corneal staining Recurrent corneal erosions (RCE) Infection Vascularization Post-Corneal Surgery CL Fitting Post-Fitting Complications

© The International Association of Contact Lens Educators Transverse incisions used in an attempt to correct induced astigmatism Post-Corneal Surgery CL Fitting

© The International Association of Contact Lens Educators Infection Epithelial in-growth Recurrent corneal erosions (RCEs) Corneal oedema Globe rupture Stellate iron lines (epithelial Fe deposits) Post-Corneal Surgery CL Fitting RK Post-Operative Complications

© The International Association of Contact Lens Educators Over-correction Under-correction ↑ astigmatism ↓ best-corrected VA Diurnal ↕ in vision Myopic or hyperopic shift ↓ contrast sensitivity ↓ tolerance of glare Post-Corneal Surgery CL Fitting RK-Induced Optical Problems

© The International Association of Contact Lens Educators Argon-fluorine excimer LASER (Ar-F) Emission wavelength of 193 nm High photon energy breaks molecular bonds → precise tissue removal Minimal thermal damage to adjacent tissue Post-Corneal Surgery CL Fitting Photo-Refractive Keratectomy (PRK)

© The International Association of Contact Lens Educators Persistent stromal scarring early or late onset Optical degradation: loss of BCVA halos, contrast sensitivity Decreased corneal sensitivity Risk of infection Steroid complications Post-Corneal Surgery CL Fitting PRK Complications

© The International Association of Contact Lens Educators Laser ASsisted In situ Keratomileusis Palikaris, 1990 For high myopia Corneal flap cut with microkeratome LASER reshaping of the exposed stroma to effect desired change Flap is replaced Usually, suturing not required Bowman’s Layer preserved Post-Corneal Surgery CL Fitting LASER-Assisted in situ Keratomileusis (LASIK)

© The International Association of Contact Lens Educators Poor microkeratome cut surgeon’s (in)experience loss of suction too deep ® corneal perforation Flap complication no hinge formed (detached flap) too thin too thick wrinkling Post-Corneal Surgery CL Fitting LASIK Complications 1

© The International Association of Contact Lens Educators Epithelial in-growth Deposits in the flap Decentered ablation → monocular diplopia Photophobia Glare, halos Dry eye Subconjunctival haemorrhages Ptosis Equipment problems during surgery Post-Corneal Surgery CL Fitting LASIK Complications 2

© The International Association of Contact Lens Educators Refractive problems over or under correction induced irregular astigmatism decentered ablation regression Corneal ectasia insufficient stromal bed thickness Corneal inflammation/infection Flap striae Diffuse lamellar keratitis Post-Corneal Surgery CL Fitting LASIK Complications 3 GP corneal CLs on LASIK patients

© The International Association of Contact Lens Educators Post-Corneal Surgery CL Fitting Failed LASIK: Post-Surgical Corneal Topography (Secondary Ectasia)

© The International Association of Contact Lens Educators Post-Corneal Surgery CL Fitting Failed LASIK: Post-Surgical Corneal Topography (Secondary Ectasia)

© The International Association of Contact Lens Educators Post-Corneal Surgery CL Fitting Intra-Stromal Corneal Ring Implants Barraquer (1949) was first to discuss intacs developed during 1990s intacs approved by FDA 2004 Other intra-stromal products introduced subsequently intacs SK Ferrara Ring Keraring Cornealring

© The International Association of Contact Lens Educators A ‘mechanical’ correction device made from PMMA 4 D myopia limit before spherical aberration becomes a problem mm diameter Range of thickness mm thickness dictates refractive effect Inserted in peripheral stroma two thirds corneal depth insertion is not a simple procedure Full circle, split-ring shape (one piece) or two ‘(’ segments Post-Corneal Surgery CL Fitting Intra-Stromal Corneal Ring Implants

© The International Association of Contact Lens Educators Post-Corneal Surgery CL Fitting Intra-Stromal Corneal Ring Implants Insertion 68% of corneal thickness

© The International Association of Contact Lens Educators Patients with collagen, vascular, autoimmune, or immunodeficiency disease Pregnancy or breastfeeding Keratoconus Recurrent corneal erosions (RCEs) Corneal dystrophy Users of: isotretinoin (Accutane) amiodarone (Cordarone) sumatriptan (Imitrex) Post-Corneal Surgery CL Fitting Intra-Stromal Corneal Ring Implants: Contra-Indications

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