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CORNEA + CONTACT LENS FINAL
ADAPTATION TO GPs
INTRODUCTION
- ADAPTATION contains and O2-component and a fit-component
- PRIOR: adaptation used to be driven by lack of O2
- CURRENT: adaptation now driven by edge comfort and mechanics of lens
RESEARH STUDIES
STUDY SET-UP FINDINGS
Mandell, Harris - Fit one eye of 4 unadapted patients w/ - 3-4% corneal swelling in contralateral eye due to reflex
(1969) PMMA lens tearing from interaction of GP edge w/ cornea
- Measured corneal swelling of contralateral - Reflex tearing lowers tear tonicity and results in K-edema
eye
Mandell, Polse, Fatt - Fit PMMA bilaterally to 4 unadapted - A-adaptors: maximum K-swelling of 5% (swelling due to reflex
(1970) patients tearing); K-swelling decreased to 2% after day 1 (swelling due to
- Measured maximum corneal swelling & lack of O2); fully adapted by day 9
adaptation - B-adaptors: maximum K-swelling of 7%; K-swelling decreased to
4% after day1; fully adapted by day 17
- Maximum K-swelling occurred after 3 hours of wear
o Basis of CL f/u instruct patient to wear CL 2-4hrs prior to
visit bc want to see CL at worst
Mandell, Polse, Fatt - Fit 1 A-adaptor w/ AC PMMA - Maximum K-swelling of 9-10% 2 hrs after fitting
(1971) - Adaptation is related to fit
o Steep fit (AC) will keep tears from sufficiently getting under
lens lack of fresh O2 to cornea
Brungardt, Potter - 101 eyes of 53 patients fitted w/ PMMA - Km steepened during 1st 5 days
(1971) o Due to swelling (reflex tearing, lack of O2)
- K-molding occurred
o Distortion no longer seen from lack of O2
o Distortion due to fit of lens + lens bearing on cornea
Lens fit/bearing will reshape cornea can mold away
some toricity + make cornea more spherical
Molding can cause spectacle blur
- Adaptation complete by 30 days
- 75% were good adapters (A-adapters)
Portz, Brungardt - Fitted unadapted patients w/ PMMA, CAB - Faster adaptation with higher Dk material
(Dk 5), and SA (Dk 10)
Bennet (1997) - 40 unadapted subjects received anesthetic - Anesthetic group rated overall GP comfort/satisfaction
- 40 unadapted subjects received placebo higher
- PROS of anesthetics
o Better initial experience
o Fewer dropouts
- CONS of anesthetics
o Must adapt to the edge w/o anesthetic eventually
Anesthetic wears off
o Anesthetic softens the cornea greater risk of abrasion
Cannot feel if anything caught under lens
o Cannot put anesthetic in rewetting drops
GP TIPS
- Fitting
o Stay calm + exude confidence
o Give patient something to do (distracts patient from feeling of the edge)
o Instruct patient to look down (decreases blinking)
o Instruct patient to blow nose (decreases tearing)
o Use anesthetics
- Dispensing
o Break in the CL gradually
Avoid looking down and have patient look around to get used to sensation of the edge
interaction w/ eyelid
o Exude confidence
Be positive & encourage/reinforce patient
o Discuss a wearing schedule
Build up wear time over first week
2-3 hours the first day + build up an hour each day
Work around patient’s schedule (after school, after work, take breaks)
Apply one hour after awakening and remove one hour before bedtime
Allows eye to rejuvenate btwn sleeping lack of O2 and CL lack of O2
- Follow-up
o Assess if patient is happy with their vision and the comfort
Look at the patient, talk with the patient, how do THEY feel about their contacts
o Assess corneal physiology
Corneal edema (O2 issues more prevalent in EW, low Dk materials)
Corneal staining (mechanical issues more prevalent than lack of O2 issues)
o Assess patient compliance
Wear time
Care system (show me your routine)
Follow-up care
O2 DEPRIVATION ISSUES
- Edema/distortion indicators
o Edema & lack of O2 issues not as prevalent anymore due to high Dk materials
o Mechanical issues and fit are now the main source of discomfort/poor adaptation
Indicator A-adaptor B-adaptor
SLE ≤ 1+ edema/staining ≥ 2+ edema/staining
Manifest VA ≤ 3 letters worse > 3 letters worse
K-distortion None Distortion
Km ≤ 0.50D steeper > 0.50D steeper
Management Increase wear time OK Fit problem + decrease wear time
- Central corneal clouding: hazy/clouding from localized edema/swelling due to lack of O2
o Seen with: low Dk material or AC fit (poor tear exchange)
- Striae: vertical stretch marks found deep in stroma from swelling/edema due to acute lack of O2
o Seen with: diabetics, k’conus, low Dk toric SCL, EW low Dk toric SCL (not as common with RGPs)
o May appear like a corneal nerve but does NOT go out to limbus and does NOT bifurcate
- Microcysts: small fluid vacuoles found anteriorly in cornea (sub-epithelium) from long-term O2 deprivation
o Seen with: EW low Dk lenses
o Found w/ retro-illumination
NORMAL/ABNORMAL ADAPTATION
NORMAL ABNORMAL
o Better materials = lower incidence of adaptation problems o Sudden pain (FB sensation)
o Tearing (should see progress while patient still in your chair) o Persistent halos
o Minor irritation (tickling, awareness of lens) o Severe redness or irritation
o Intermittent blurry vision (due to tearing/lens wetting) o Spectacle blur > 1 hour
o Light, wind, dust sensitivity o Increasing eye discharge
o Mild redness o Lens adherence
o 1+ degree o 4+ degree
LONG TERM WEAR EFFECTS
- Lower incidence of long term issues due to better materials
- Keratometry: steeper/flatter K, distorted mires (results when lens doesn’t center/contour corneal well)
- Subjective refraction: spectacle blur (results when lens doesn’t center/contour corneal well)
- Biomicroscopy: corneal staining (glimpse into how lens fits/mis-fits and what changes need to be made),
polymegathism/polymorphism
- K-topography: corneal warpage, corneal exhaustion
DEPRIVATION
- Reasons for deprivation of CL
o Refit (deprivation not necessary)
o Compromised cornea
o Refractive surgery
- Refit
o Combining the FP, OR, and better material will stabilize the CL and cornea very quickly
No need to deprive patient of their CL to refit many patients do not have specs & many
patients will experience spectacle blur/distortions
o Base curve: k’metry or FP
Re-fit by FP with goal of AA
K-values can change 2-3D (not as reliable)
o CLP: SR or OR
Re-fit by OR (SAM/FAP)
SR can be all over the place
o Material: Dk
Re-fit in a better Dk material
- Refractive surgery
o Deprivation time: time out of CL is not the issue
Every surgeon has own CL deprivation times prior to corneal surgery
Times are not based on anything (arbitrary)
No formula for deprivation time each individual is different
One individual’s deprivation time might not be enough for another individual
o Corneal stability: stability of cornea is more important prior to refractive surgery
Repeatable SR
Good SR VA
Repeatable K’s
No K-distortion
Stable topography indicies: not as sensitive as SR and K-values/distortion
Good tear film: dry eye needs to be treated before surgery
No cone present: k’conus more noticeable and harder to manage after refractive surgery
COMPLICATIONS OF GP LENS WEAR
GP LENSES GENERALLY HEALTHIER THAN SCL
- Smaller OAD = less corneal coverage + greater tear exchange
- Complications = fewer + less severe
- Properly fitted GP lenses provide:
o Good comfort
Important to patient
Scleral lenses more comfortable than smaller OAD lenses that have more lid interaction
o Good vision
Precise OR
Correct astigmatism when needed
o Sufficient wearing time
o Good corneal health + good tear film
- Good corneal health depends on:
o Well designed/fitted lens
No excessive edge lift (err on side of max PC bc minimal PC creates poor movement & poor tear exchange)
Minimal PC offers good centration and good comfort
High Dk material (no less than 60)
Good wetting material (clean and soak before dispensing)
o Central/stable lens position (slightly superior OK)
o Adequate lens movement
o Sufficient tear exchange (adequate edge clearance = adequate tear exchange)
- GP lens complications arise when 1+ factors are not met
o Complication defined by FDA as losing 2+ lines of vision
o Corneal staining (due to misfit of lens)
o Corneal distortion/irregularities (due to lens position/fit)
o Corneal problems dellen, VLK, PCD, dimple veil, hypoxia
o Decreased VAs
o Decreased WT (due to dryness)
o Decreased lens comfort (due to EW, poor lens design, fit, edge interaction)
o Increased lens awareness (due to dryness or poor lens design)
PERIPHERAL CORNEAL DESICCATION: 3-9 staining
- What: localized area of dryness
- Location: position of staining dependent on lens-cornea relationship
o 3-9 o’clock: lens centered (nasal/temporal dryness)
o 4-8 o’clock: lens riding high (lower dryness)
o 2-10 o’clock: lens riding low (upper dryness)
- Symptoms: none
- Biomicroscopy signs
o Staining shows areas of SPK at 3 & 9 o’clock regions
o Use yellow filter in conjunction w/ slit lamp to observe subtle staining
- Severity
o Mild: small areas of non-coalescing superficial punctate staining
o Severe: coalescing areas of SPK with heavy/deep fluorescein staining
- Reasons for concern
o Sign of dryness (3-9 staining depends on wetness, NOT oxygen)
o Avenue for infection
o Long-term PCD may lead to dellen formation
o Scarring
- Causes
o Minimal PC minimal edge lift leads to poor lateral lens movement upon blink (lens too tight)
o Maximal PC excessive edge lift leads to areas of poor rewetting
Tear film disrupted leading to dryness + disruption of corneal epithelium
Lids being held away from lens leading to poor rewetting
o Incomplete blink/lagophthalmos
o Inferior GP lens position
- Management
o Discontinue lens wear (moderate to severe)
o Continue lens wear w/ ATs while waiting for new lens (mild to moderate)
Educate patient on ATs because they don’t have dry eye sx
o Bandage SCL under existing RGP (chronic)
Provides more moisture does NOT change fit/power
o Antibiotic (severe)
o Educate patient on awareness of complete blinks and increase blink frequency
o Modify edge decrease edge lift to increase lid apposition to peripheral cornea
Steepen BC
Steepen peripheral curves
Thinning edge profile (plus lenticularizing minus lenses >-5D)
- Edge-lift (holden study)
o Setup
Q: is more edge lift better?
More edge lift = more tear exchange
Fit 16 pts with silicon acrylate GPs with 0.08mm edge lift
Increased edge lift by flattening secondary curve radius
o Results
As edge lift increased, percentage of 3-9 staining increased
As edge lift decreased, percentage of 3-9 staining disappeared
o Conclusions
3-9 staining is fit related, NOT material related
3-9 staining treated by decreasing edge lift via steepening 2ndry curve or thinning edge
DELLEN
- What: localized area of reversible thinning due to thinning of epithelium, bowman’s, and stroma
- Location: adjacent to an area of elevation (ex: GP lens edge, pinguecula)
- Symptoms: none
- Biomicroscopy signs
o Kidney-bean shaped depression at limbus or adjacent to area of elevation
o Fluorescein pooling in excavations
o Minimal staining
o Slit lamp beam bends as crosses over dellen
o NO: infiltrates, AC reaction, cells/flare, hyperemia
- Reasons for concern
o If untreated, vascularization & scarring can occur
o If untreated, prone to infection
- Causes
o Desiccation or dehydration of peripheral cornea seen w/ GP lens wearers
o Severe PCD
o Tear film instability + poor wetness
- Management
o Eliminate the cause
Steepening GP peripheral curves for increased corneal apposition
Thinning edge profile of lens
Surgical removal of pingueculae
o Copious lubrication
ATs in the AM (every ½ hour)
Viscous gels in the PM
o Antibiotic
DIMPLE VEILING
- What: indentations of the cornea (no breaks in epithelium)
- Location: central or mid-peripheral
- Symptoms
o None if peripheral
o Visual blur if central involving visual axis
- Biomicroscopy signs
o Needs NaFl to be seen
o Dimple veils are circular, well-demarcated pools of fluorescein
o Single or multiple
- Reasons for concern
o Blurred vision if centrally located
o Rarely progresses to other issues unless dimples become immobile
- Causes
o Air bubbles trapped underneath lens
o CO2 efflux from cornea due to area of lens clearance
- Management
o Dimples will self-resolve if lens wear is discontinued
Time of discontinued lens wear depends on length of time dimples were present
o Lens alterations
Flatten BC (if dimples central)
Decrease OZD (if dimples mid-peripheral)
Heavy blend on jxn btwn BC and PC’s allowing for better tear mvmt/exchange
- “Dimple veil” in silicone-hydrogels
o What: mucin balls (spherical particles of mucous, lipids, proteins in post-lens tear film)
o Caused by: flat fitting silicone-hydrogel lenses used for EW
o Symptoms: none
o Resemble: dimple veiling from GP lens wear
VLK: vascularized limbal keratitis
- What: rare inflammatory condition of cornea in which superficial & deep vascularization emanating from
conjunctiva encircles the infiltrate and raised epithelial mass
- Location: conjunctiva/corneal limbus
- Symptoms: pain, redness
- Biomicroscopy signs
o Invasive vascularization
o SPK & epithelial chafing
o Epithelial heaping (elevated limbal epithelial mass)
o Acute hyperemia
o Vascular leash
- Causes
o Initially caused by desiccation or tear film disturbances associated with lens edge-lift
o Chronic dryness/irritation from persistent 3-9 staining
- Reasons for concern
o If untreated, elevated epithelium may erode (painful)
- Management
o Eliminate cause by temporarily discontinuing lens wear
o Stop inflammatory process
Rx ocular lubes and decongestants constrict vessels + limit permeability of vessel
Rx topical steroid treat infiltrate and regress vascularization
o Refit GP lens for long-term mgmt
Smaller OAD
Flatter PCs to prevent chafing (CAUTION: flat PCs may disturb marginal tear meniscus)
HYPOXIA
- What: decreased availability of O2 resulting in an increase in CO2
- Prevalence: less common today due to higher Dk materials but found with EW + PMMA lenses
- Stromal edema
o What: 8-10% swelling due to influx of water into stroma
o Caused by: accumulation of lactic acid from increased anaerobic metabolism
o Importance: amount of swelling inversely retated to amount of O2 in tears
- Microcysts
o What: small 0.01 – 0.1mm transparent epithelial inclusion bodies found deep in epithelium
o Caused by: chronic hypoxia (at least 2-3 months)
o Importance: inclusions break and stain as they travel anteriorly through epithelium
Best seen w reverse illumination
- Striae/folds
o What: fine white vertical lines
o Caused by: corneal edema
5-6% corneal swelling = striae
10-12% corneal swelling = folds
o Importance: seen more with low Dk EW SCL
- Management
o Mild cases: decrease wear time
o Moderate cases: refit w/ higher Dk material + decrease wear time
o Severe cases: discontinue lens wear until neovascularization/chronic SPK regresses; refit lens
MECHANICAL COMPLICATIONS
- Foreign bodies
o Reason for concern
Abrasions; epithelial staining
Tear pump or lens movement can dislodge FB
o Symptoms: irritation
o Biomicroscopy signs
FB tracks appear as thin linear streaks that stain w NaFl
FB tracks show movement of FB w lens mvmt & blink
o Management (depends on severity of abrasion)
Prompt removal/irrigation of FB
Mild staining: discontinue lens wear for 24 hrs; rx ATs
Moderate staining: prophylactic antibiotic drops
- GPC: giant papillary conjunctivitis
o What: mechanical insult caused by rigid lens edge + deposit formation
o Biomicroscopy signs
Large bumps found on upper palpebral conjunctiva
Lid inflammation (due to deposits)
o Management
Discontinue lens wear
Enzymatic cleaners to remove deposits
- Impression rings
o What: marks left on cornea due to tight fitting GP lens (flat lens or steep PC)
o Signs/symptoms
Corneal distortion
Spectacle blur
Mild-to-no staining
o Treatment
Discontinue lens wear
Refit w/ steeper BC or flatter PC
TOXICITY
- Causes
o Red tip cleaners
o H2O2 care systems
o Poor rinsing of lenses
- Signs
o Diffuse SPK
o Conjunctival injection
DRY EYE (dr. kwan)
INTRODUCTION
- Definition
o Dry eye is a multifactorial disease of the tears, eyelids, and ocular surface that results in symptoms of
discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface
o Dry eye is accompanied by increased osmolarity of the tear film & inflammation of the ocular surface
- Symptoms
o Dry o Itchy, scrathcy
o Uncomfortable o Foreign body sensation (distinguishes MGD from ADDE)
o Irritated o Gritty, sandy
o Tired o Sore, painful
o Burn o Sensitive to light
o Fluctuating/blurry vision o Sticky
o Red o Difficultly removing SCL
- Tear film
o 3 thick (3000nm)
o 3 dynamic, non-distinct layers
Lipid layer: 40-120nm thick; elastic; outermost layer; provides hydrophobic barrier
Aqueous layer: viscous; bulk of tears; promotes spreading of tear film and control of infectious agents
Mucin layer: innermost layer; produced by conjunctival goblet cells; enables tear film to adhere to epithelium
- Types of dry eye
o 80%- Evaporative Dry Eye (EDE) = Meibomian Gland Dysfunction (MGD)
Inflammatory (blepharitis)
Non-inflammatory (obstructive or atrophic)
Intrinsic (meibomian oil def, disorders of lid aperture, low blink rate)
Extrinsic (vit-A def, topical drugs, CL wear, ocular surface disease)
o 20%- Aqueous Deficiency Dry Eye (ADDE)
Sjogren’s (autoimmune)
Non-sjogren’s (lacrimal def, lacrimal gland duct obstruction, reflex block, systemic drugs)
o Mixture: EDE + ADDE
o Other
Ocular allergy
Epithelial basement membrane dystrophy
Recurrent corneal erosion
- Prevalence
o 5-30% US population (different numbers due to different dry eye definitions)
17% globally | 30% in Asians
o 44-75% of CL wearers
o 40% of people have MGD (altered oil secretion)
- Risk factors
o Age: older people
o Gender: females > males
o Systemic disease
Autoimmune diseases (arthritis, lupus, sjogren’s)
Diabetes (rate of corneal healing is impaired after epithelial damage)
o Hormonal insufficiency: testosterone = dry eye (peri- and post-menopausal women)
o Iatrogenic causes
Ocular surgery: LASIK, cataract surgery (corneal nerves cut cant sense dryness, cant make tears)
CL wear (disrupts tear film and increases evaporation)(splits thin tear film into pre-tear lens and post-tear lens)
Medications: antihistamines, diuretics (only takes 4 days for TBUT to drop and staining to increase)
Computer use (blink rate decreases, fewer breaks)
Environmental stress: low humidity, dust, smog, AC vents, airplanes
Smoking
Alcohol, hydration level
- CL-related dryness
o CL disrupts tear film and increases rate of evaporation
o Underlying dry eye
o CL-solution incompatibility
Educate patient: not all solutions created equal
Not everyone can tell
Generic solutions known to cause greater area of staining
Educate on mechanical rubbing to loosen deposits
Ask about solution on f/u visit
Start with: MPS (puremoist, revitalens, biotrue)
Problem-solver: clear care (no-rub soln, loosens deposits well)
o CL-patient incompatibility (high Dk lens ≠ less dryness)
o Non-compliance lens overwear, lens deposits
DRY EYE DIAGNOSIS
- PC/CL examination dry-eye evaluation
o Biomicroscopy (lid margin eval)
o TBUT
o Schedule dry-eye workup if needed
- Comprehensive dry-eye evaluation billed to medical insurance
o Billing codes: 99213 ($100) or 99212 ($55)
o Diagnosis codes: 375.15 (tear film insufficiency) or 370.33 (KCS no specified as sjogren’s)
o Get to know your rheumatologist + dermatologist (many arthritis/rosacea patients will have dry eye)
- Prior to comprehensive dry-eye evaluation
o No CL wear for 2 days prior to appt (allows tears to restabilize and cornea/conj to heal)
o Good night sleep night before exam
o No eye drops day of exam
o No eye-makeup day of exam (mascara/eyeliner can mask eyelid margins and can float into tears)
o Bring list of all current meds and eye drops (OTC, vitamins, supplements, allergy, systemic, eye, ATs)
- SCCO comprehensive dry-eye evaluation
o Least invasive to most invasive PRN
o Case history
o Schein or OSDI Questionnaire: provides sense of severity
o BCVA
o Topographer surface regularity index: >0.80 is irregular
Poor tear film will result in inaccurate topography
Oculus keratograph: topographer also allows NIBUT testing and measures tear meniscus
height on top of fitting GP lenses and diagnosing k’conus
o Interferometry/tear film analysis: jagged/multi-colored is abnormal; smooth/white is normal
Interferometry is a judgement of tear film oily-ness
o Tear osmolarity: >308mOsms/L is abnormal
Tear osmolarity measures salt/concentration of tears
TearLab: device samples small amount of tears; higher of 2 readings is used
Allows diagnosis of severity and monitoring effectiveness of treatment
Good specificity/sensitivity
o Biomicroscopy: lid margin eval
Capped glands
Telangiectasia (tiny blood vessels seen in eyelid margin)
o TBUT: ≤7sec is abnormal
o Corneal staining w/ NaFl: amount of stain and location/pattern
Whole cornea stain CL solution induced
Limbal area stain CL removal, tight fit
Lower 1/3 stain lagophthalmos, partial blinkter
3-9 stain excessive GP edge lift
o Conjunctival staining w/ lissamine green: coalesced or diffuse
Conjunctival staining often due to knife edge interaction
o Meibomian gland expression: thick/opaque is abnormal; clear is normal
Gentle expression w/ q-tip for diagnosis
Forceful expression w/ mastrota paddle for treatment
o Meibomian gland dropout: n=24 is normal; more dropout seen nasally/temporally than central
Meiboscopy: use transilluminator to evert lower lid and backlight MGs
Meibography: assess if MGs are normal, shortened, or missing; calculate dropout %
o Schirmer I test: <5mm in 5min is abnormal designates aqueous deficiency
Measures maximum ability to produce tears
Done w/o anesthetic to provoke reflex tearing
Distinguishes btwn aqueous deficiency and MGD
o Phenol red thread test: <5mm in 15sec is abnormal aqueous deficient
- Dr. Kwan’s minimal dry-eye workup
o Careful case history
What patient feels can be different than what optometrist sees
Common patients with dry eye: fibromyalgia, sleep apnea, arthritis, rosacea
Environmental conditions associated w dry eye: AC, cold mornings, wind, light sensitivity
o Schein questionnaire
o Biomicroscopy eyelid/ocular surface evaluation
o TBUT
o Corneal staining w NaFl
o Conjunctival staining w lissamine green
o MG expression
o Meiboscopy
o LOTS of patient education
DRY EYE MANAGEMENT
- Customize treatment management to patient and treat according to etiology
Meibomian gland dysfunction Aqueous tear deficiency
- Warm compresses and lid massage - ATs (systane ultra, optive)
- Omega-3 FAs - Omega-3 FAs
- Doxycycline or minocycline - Restasis (cyclosporine A)
- Oil-based ATs (systane balance, soothe XP) - Lotemax
- Azasite - Punctual plugs (temporary/permenant)
- Lines of defense
1st line of defense - ATs + ointments
- Eyelid hygiene (warm compress/lid massage)
- Environmental modifications
2nd line of defense - Oral medications (tetracyclines, omega-3s)
- Topical anti-inflammatory meds
- Consult PCP to modify systemic meds
3rd line of defense - Punctual plugs
- Bandage soft or scleral contact lenses
- Moisture chamber glasses
4th line of defense - Autologous serum (eye drops made from own blood plasma w growth factors to promote healing)
- Surgery (lid, tarsorrhaphy)
- Triad of treatment to ensure patient success: (1) ATs (2) short course of Lotemax (3) omega-3s
- More information on various treatments
o Meibomian gland expression
Mastrota paddle used on palpebral conjunctiva side for forceful expression
Evacuates thick abnormal oil so fresh new oil can be produced
o Artificial tears
Lubrication to soothe irritation and feeling of dryness
Types: oil, aqueous, gel, ointment
5 different Systanes (original, ultra, balance, gel, ointment)
Dr. Kwan’s favorite ATs: oasis tears (non-preserved); systane ultra (application + rewetting
drop for SCL and GPs); systane balance
o Medication
Anti-inflammatories (Lotemax, FML forte)
Reduces inflammation
Steroid drops measure and monitor IOP
Immuno-modulator (Cyclosporine or restasis)
Increases tear production by helping lacrimal gland produce more normal tears
Reduces inflammation
Extends hours of comfortable CL wear
PRO: subjective success; success/compliance when coupled w other therapies
CON: takes at least 3 months to see benefits; many adverse effects; doesn’t create
drastic improvement in aqueous production (may increase TBUT from 1.21 to 3.24 but 3.24 is
still considered abnormal)
Antibiotics
Erythromycin ointment used for severe bacterial blepharitis
Azasite azithromycin used for bacterial conjunctivitis; helps MGD
Tetracyclines doxycycline/minocycline used for MGD and rosacea
o Low doses used to prevent side effects
o Omega-3 FAs
Every person should have 650mg of EPA/DHA per day regardless of health status
Benefits
Both Omega-6 and Omega-3s are anti-inflammatory when ratio is < 4:1
o EPA/DHA in Omega-3s has anti-inflammatory effect
o Omega-6s become pro-inflammatory when ratio is > 4:1
o Typical N. American diet has a ratio of 15:1
Omega-3s promote cardiovascular health as well
Sources
Dietary supplementation
Diet (salmon, trout, sardines, oysters, tuna)
Triple strength fish oil capsules (980mg EPA/DHA per capsule)
Cautions
High doses of Omega-3s can act as blood thinner
Check labels many say 1000-1200mg per capsule but only have 300mg of EPA/DHA
Our body only has 10% conversion rate of -linolenic acid to EPA/DHA skip flaxseed
oils and concentrate on fish and fish-oils
o Moisture goggles
Insulates the eye from external environment
Creates a high humidity environment to stabilize the tears
o Lid scrubs + compresses
Promotes lid hygiene
Loosens hard oil that may be blocking meibomian gland
o Omega 7s
Source: sea buckthorn oil
Benefits
Protects, hydrates, improves skin quality
Comforts and lubricates internal mucous membranes
Cons: minimal scientific evidence
o Contact lens treatments
Newer silicone hydrogel CLs w wettability coating
GP lenses
Scleral lenses: large OAD holds sterile saline on the eye all day and provides protection from
external environment
Bandage contact lens: steeper BC, temporary EW lens protects corneal surface from
mechanical abrasion of eyelid to heal persistent epithelial defects
o Advanced treatments
Intense pulse light therapy: pulsing upper cheek area w/ light stimulates MGs & improves
secretion
Intraductal meibomian gland probing: probing MG with needle to loosen hard oil
Lipiflow thermal pulsation system: in-office warm compress treatment that heats MGs from
inside while pulsating and pushing oil out of glands
- Managing dry eye in CL wearers
o Warm compress and lid massage daily in shower
o ATs before applying CLs makes ocular surface more wettable
o Hypoallergenic and good-quality makeup
o Rewetting drops during the day (systane ultra, blink, refresh optive, etc)
o Reminders to blink and take breaks w/ extended near tasks
o Omega-3s
o Short-term doxy/minocycline
TAKE HOME MESSAGE
- Dry eye is the most common eye condition but most treatable by optometrists
- Treatment of dry eye can proactively prevent CL dropout & improve quality of life
REFRACTIVE SURGERY (dr. tran)
INTRODUCTION
- LASIK does not take away money/patients from practice
o OD gets 20% of LASIK price for co-management (~$800)
o High myopes need annual DFE due to higher risk of retinal problems due to axial length
o Patients still need plo sunglasses + readers
o Patients still have vision insurance
- Co-management
o Increases your liability if something goes wrong, your name is attached to the case
o Includes ~7 visits (pre-op and post-op visits) to monitor corneal health
- Goal of refractive surgery
o Reduce need for glasses and CL (decrease dependency on eye wear)
Never guarantee that patient will not need another pair of glasses
o High myopes benefit most from LASIK
REFRACTIVE PROCEDURES
- RK: RADIAL KERATOTOMY
o History: Dr. Leendert developed concept of flattening cornea via incisions made on anterior surface
Incisions = flatter cornea = less corneal power = patient less myopic
o Procedure: series of radial incisions made on cornea (start w/ 8 incisions, adding 4 as needed)
o Corrects for: low myopia (1.00-3.00D)
o Problems
Freehand procedure creates problems w consistency/predictability
Corneal depth? Straight incisions? Length of incisions?
Decrease corneal integrity over time due to irregular astigmatism
Vision great for 5yr and then patients deteriorate to high + rx
Visual problems: over/under correction, irregular astigmatism, glare/halos from small OZD
Limbal involvement: corneal neovascularization
- AK: ASTIGMATIC KERATOTOMY
o Procedure: horiztonal/vertical cuts along meridian of astigmatism to flatten cornea in that meridian
H cuts = ATR correction; V cuts = WTR correction
Incisions “relax” corneal tissue to produce more spherical shape
o Corrects for: astigmatism
o Problems: same as RK
- ASA/PRK: ADVANCED SURFACE ABALATION/PHOTOREFRCTIVE KERATECTOMY
o Procedure: excimer laser removes 50 of corneal epithelium & sculpts exposed tissue
Loosens/removes corneal epithelium/bowmans to expose corneal stroma
Cornea reshaped to correct for patient’s prescription
Bandage CL placed over open wound
o Excimer laser: non-thermal laser beam of excited dimer molecules used in photoablation
Plume-effect: beam releases molecules from tight binding creating cloud of free molecules
Leaves clean/precise edges
o Corrects for: low-moderate myopia (≤7.00D), astigmatism, hyperopia
Beyond -7.00D depends on corneal thickness
Results less predictable for hyperopia
o Pros/cons
PRO CON
- OK for thin corneas - Open wound leaves stroma exposed bandage CL used
- No flap complications - Delayed vision for 1-2wks as epithelium healed
- Better long-term corneal integrity - Discomfort for ~6mo
- Predictable, precise - Risk of stromal haze
- Good for pts w/ EBMD - High risk of infection/inflammation
- Retreatment possible - Steroids for ~1mo (risk of high IOP; not good for glauc pts)
o Mitomycin C
Topical drug applied after laser treatment
Reduces incidence of corneal scarring/hazing
PRK renamed to ASA regaining popularity
o Post-surgery management
Antibiotics QID to prevent infection
NSAIDs QID to manage pain
Daily follow up to monitor epithelium regrowth
After epithelium completely reformed, remove bandage CL and begin steroid treatment to
reduce risk of corneal scarring/hazing
- LASEK: LASER ASSISTED IN-SITU EPITHELIAL KERATOMILEUSIS
o Procedure
20% alcohol solution loosens corneal epithelium so 50 flap can be lifted back
Excimer laser sculpts cornea to correct the RE
Epithelium is replaced over stromal bed
Bandage CL applied over open wound
o Epi-Lasik
Blunt oscillating blade (epi-microkeratome) used to create corneal flap instead of alcohol
Same procedure as LASEK
o Corrects for: low-moderate myopia (≤9D), astigmatism, hyperopia
o Pros/cons
PRO CON
- Recovery shorter than PRK - Complications during flap formation
- Patient comfort better than PRK - Open wound leaves stroma exposed bandage CL used
- Predictable, precise - Epithelial flap sloughs off + replaced
- Retreatment possible o Delayed vision as epithelium heals
- Short-term medication (AB, steroids) o Risk of stromal haze
- More discomfort than LASIK
- Recovery longer than LASIK
- LASIK: LASER ASSISTED IN-SITU KERATOMILEUSIS
o Procedure
Microkeratome or IntraLase Femtosecond Laser used to create flap of corneal epithelium,
bowman’s membrane, stroma (120-150 thick)
Flap preserves bowman’s layer
Excimer laser ablates/reshapes corneal tissue to correct the RE
o Corrects for: low-moderate myopia (≤9D), astigmatism, hyperopia
Results less predictable for hyperopia
o Pros/cons of LASIK
PRO CON
- Near-immediate vision - Complications during flap formation
o Functional w/in 24hrs; fully functional w/in 1wk - Conventional LASIK can induce higher order aberrations
- Bowman’s membrane preserved no risk of scar o Magnitude depends on amt of pre-op myopia
- Fast recovery
- Comfortable
- Customized: imprints patient’s cornea
- Predictable, precise
- Re-treatment possible
- Short-term meds (ABs, steroids)
o Flap creation
Microkeratome: blade
Many moving parts risk of mechanical breakdown + metal debris
Less control over flap thickness/formation
o Size: limited to diameter of tool
o Thick: 160
o Variability in thickness across peripheral/central cornea & across different flaps
Torsional effect
Loss of suction can cause cornea to drop back down and create “buttonhole cut”
o Must let cornea heal and will typically not try LASIK again
IntraLase Femtosecond Laser: bladeless
Infrared light beam (2-3 in size) removes tissue via photodisruption
o Laser forms microscopic bubbles of CO2 and water vapor
o Thousands of interconnecting bubbles create separation btwn stromal layers at
very precise depth
o Similar appearance to “perforated paper”
Flap
o Size: any size
o Thin: 110
o Precise flap thickness across peripheral/central cornea (minimal variability)
o Customized to patient’s corneal thickness
Advantages/disadvantages
PRO CON
- Bladeless no complications from blade - Cannot penetrate scars
- Consistent, repeatable, predictable, precise - Opaque bubble layer bubbles trapped
o Flap thickness + size precise and flap cant be cut
o Hinge location controlled - Elevated IOPs for longer duration
- Corneal surface + flap edge smoother
- Allows for thinner flaps for thinner corneas
- Fewer corneal nerves damaged
- Customized to patient
- Patterned edges edge locks into base
o Less tension in suture
o Less alteration in K-topography
o Minimize amt of endothelial cells being exchanged
o Prevent epithelial cells from migrating into stroma
- Used in corneal transplant patients
o LASIK add-ons
Wavefront-guided or wavefront-optimized: custom LASIK to remove/prevent HOAs
Active eye-tracking: high-speed computerized eye tracking to maintain the alignment of the
laser with the position or movement of the eye
Iris registration: accounts for cyclorotation of the eye
- CK: CONDUCTIVE KERATOPLASTY
o Procedure
Steepening of central cornea
Controlled radio frequency energy shrinks small areas of corneal collagen in circular pattern
around peripheral cornea
o Corrects for: low hyperopia (+0.75-3.00DS), presbyopia, astigmatism (≤0.75DC)
o Pros/cons
PRO CON
- Near immediate vision; immediate recovery - Retreatment necessary (effects only last 3-5yrs)
- Comfortable (mild FB sensation) - Corneal scarring permanent
- Predictable, retreatable - Small OZ in high Rx
- Short term meds - Monocular procedure temporary monovision
- INTACS: INTRACORNEAL RING SEGMENTS
o Procedure
2 channels are made in peripheral cornea via IntraLase
PMMA segments inserted into channels in peripheral corneal stroma
o Corrects for: low myopia, k’conus
Arc-shortening effect: rings apply pressure to peripheral cornea central cornea flattens
Segments provide support and thickness to thin, weakened cornea
Procedure does NOT remove more corneal tissue
o What patients should get INTACS
GP lens intolerant
Keratoconus
Pellucid marginal degeneration
Post-LASIK ectasia
o Corneal health requirements
Clear central cornea
No scarring
Max K-value of 57D
No corneal neovascularization
o INTACS does not
Halt or reverse progression of corneal thinning disease
Completely rid dependence on GP lenses or other visual correction
o GOAL: improve CL fitting success
- CLE: CLEAR LENS EXTRACTION
o Procedure: internal lens of eye is removed and a lens implant of a different power is implanted
o Corrects for: hyperopia, high myopia, presbyopia, high rx’s
o Recommended for: patients over 40 with high rx (near cataract age)
o Not recommended for: younger patients bc younger patients will lose ability to accommodate
- ICL: IMPLANTIBLE COLLAMER LENS
o Procedure: artificial lens implanted behind/in front of iris with natural lens remaining in place
Essentially, an internal contact lens
o Corrects for: high amounts of myopia (>11D)
o Recommended for: younger patients with high rx
o Caution: touching natural lens during surgery will induce cataract & warrant removal of natural lens
ABERRATIONS
- Aberrations = errors of the entire eye (cornea, lens, shape, length, etc)
o Lower order aberrations: sphere and cylinder refractive error
Only treated via specs/CLs
o Higher order aberrations: coma, spherical aberration, distortion, etc
- Zywave Wavefront Aberrometer
o Narrow laser beam focused on retina to generate single, focused point source
o Outcoming light rays bent by aberrations caused by refracting media (cornea, lens, vitreous)
o Sensor detects how much outcoming rays deviate from original incoming rays
- Custom LASIK
o Aberrometer uses wavefront analysis to measure aberrations unique to individual
o Custom LASIK interfaces the aberrometer w/ the laser to eliminate higher order aberrations (HOAs)
o Wavefront-guided: ablations treat refractive error and pre-op HOAs
o Wavefront-optimized: ablations treat refractive error while preventing induction of post-op HOAs
LASIK/ASA POWER RANGES
- Correction HIGHLY dependent on corneal thickness varies by individual
- LASIK/ASA
o Myopes: < -11.00D sphere
o Hyperopes: < +6.00D sphere
o Astigmatism: < 6.00D cylinder power
o Higher prescriptions can be managed via CLE, ICL, or a combination of treatments
- EXAMPLE: Patient with rx of -6.00DS OD, OS wishes to have LASIK. Patient’s CCT is 500 OD and 475 OS.
If a stromal bed of 250 must be left, flap thickness is 125, and each diopter of correction requires ablation
of 16, should this patient get LASIK?
o Correction of -6.00 requires ablation of 96
o OD: 500 – 125 flap – 96 correction = 279 LASIK OK
o OS: 475 – 125 flap – 96 correction = 254 TOO CLOSE FOR COMFORT
o Suggestion: LASIK OD, PRK OS
LASIK CANDIDATES
- Patients may or may not inquire about LASIK
o Inquirers: discuss what patient wants to accomplish with LASIK; send for consultation
o Non-inquirers: don’t be afraid to ask patient if they have thought about it or why they are not
interested in it
- LASIK candidates
o Adults over 18
o Stable refractions (<0.50D change over last year; <0.25D change over last month)
When findings are repeatable, patient is ready
o Adults w/ active lifestyles (water sports, outdoor activities, etc)
o Patients with kids (avoid broken glasses, waking up in middle of night)
o Patients who cannot get around in an emergency w/o their correction
- Good LASIK candidates
o Motivated patients with realistic expectations
o Patients with much to gain (high rx’s)
o Patients who understand there are surgical tolerances
o Patients who desire good “functional” vision
o CL intolerant patients
o Patients who want less dependency on glasses/contacts
o Not an engineer
LASIK CONTRAINDICATIONS
RELATIVE ABSOLUTE PRACTICAL
- Anxiety - Severe dry eyes - Age (too old v. too young)
- Mild dry eyes - Active disease (HSV, K’conus, PMD) - Unrealistic expectations
- Lid disease (blepharitis, meibomitis) - Thin corneas - Myopic presbyopes (will lose near vision w/
- Irregular topography (wait for stability) - Extreme rx LASIK and be unhappy)
- Systemic disease (diabetes, etc) - Unstable refraction - Low refractive errors (low benefit)
- Previous corneal surgery - Unstable topography - More to lose than gain
- Amblyopia - Monocular patients - Anxious/nervous
- Pregnancy/nursing
If patient is managed for these items, they Patients with these items should NEVER
can become a good candidate for LASIK undergo LASIK look into other options
PATIENT PREPARATION
- Discontinue CL wear prior to surgery
- ABs QID day before surgery (zymar, zymaxid, vigamox, moxeza)
- Bring driver
- Eat before arrival
- Plan on being at surgical site ~2hrs
- Dress warmly
- Sleep as much as possible after
- Do not return to work same day
- Return to surgical site for 1 day check-up
