소프트 콘택트렌즈 착용에 관한 부작용

Peter B. Lee, OD

121st General Hospital

Seoul, Korea

CL 부작용의 위험 요소• Hypoxia ( 저산소증 )

– virtually all CLs reduce O2 supply to cornea

• Desiccation / Alteration of tear film(렌즈탈수 / 각막건조 )– CLs are much thicker than tear film– SCLs evaporate to the atmosphere

• Deposit build-up( 침전 )– SCL>RGP, but all develop deposits made of

proteins, mucous, lipids, dirt, and microbes

CL 부작용의 위험 요소

• Mechanical( 물리적 요소 )– Tightness & looseness– Abrasions & friction

• Inflammatory response( 염증 )– Proteins and other surface deposits– Microbes and their toxins– Solution preservatives and other components

Contributory Factors( 문제가 될 수 있는 요소 )

• Lens material– Dk( 산소 침투성 )– Wettability and deposit attraction– Stiffness and other physical characteristics

• Lens design and fitting– Lens-to-cornea relationship– Position and movement– Thickness profile

• Wearing time( 착용 시간 )– DW vs. EW– Daily vs. part-time– Patient’s physiology

• Patient compliance( 착용자의 순응도 )– Wear time– Cleaning and disinfection– Lens replacements– Follow-up visits

Effects of Hypoxia

( 저산소증에 인한 문제점 )

Effects of Hypoxia

1. Epithelial and stromal edema( 각막부종 )

2. Decrease in epithelial mitosis( 상피 분열 )

3. Increase in stromal lactate accumulation( 유산 축적 in anterior chamber)

4. Decrease in corneal sensitivity

Corneal Edema( 각막부종 )

• The cornea requires a certain amount of oxygen to prevent swelling, or edema

• During sleep, the oxygen supply is reduced to approx. 8%, compared to about 21% during waking hours

• The cornea swells 3% to 4% overnight• Therefore, it appears the cornea needs more

than 8% O2 to prevent swelling

Corneal sensitivity( 각막 민감도 )

» Millodot and O'Leary (1980) found that the cornea needs at least 8% oxygen to prevent a reduction in corneal sensitivity

Oxygen Requirements

• The cornea requires 8% to 13% O2 to maintain normal corneal thickness, metabolism, and sensitivity.

• What are today’s contact lenses able to deliver?

Oxygen Requirements

• CLs are not rated by % O2 delivered• Transmissibility (Dk/L) is a rough indicator

of how well a CL transmits oxygen • Dk/L is the most common measure to rate

how well contact lenses deliver oxygen to the cornea

• Other methods have also been developed but are not in widespread use

Epithelial Edema( 각막 부종 )

• Epithelial edema manifests as clouding of the epithelial tissue, usually centrally, with associated punctate epithelial staining, steepening of the corneal curvature and possible irregularity of the corneal surface

Epithelial Edema( 각막 부종 )

원인

• Low Dk( 산소 침투성 ) contact lens wear (PMMA more likely than soft lenses)

• Long-term, extended hours or extended wear( 연속 착용 )

증상과 진단

• Poor endpoint visual acuity

• Distorted keratometry mires, steepening of K's

• Central circular clouding (CCC)

• Punctate epithelial staining centrally

• Increased minus on refraction

치료 / 처치법

• Discontinue lens wear or immediate refit to higher Dk material

• Refit to higher Dk material• Decrease wear time• Looser fit for better tear exchange• Monitor K and SR changes

– Prescribe new spectacles when stable to allow decreased CL wear time

Stromal Edema( 고유층 부종 )

• Stromal edema manifests as fine wrinkling (striae) or folds in Descemet's membrane

• Striae and folds appear with approx. 6% stromal edema

• Stromal clouding requires extensive edema, at least 15%, and is usually not induced by contact lens wear

Stromal Edema

원인

• Thick lens design (aphakic, prism ballast), low Dk material or EW

증상과 진단

• Mild edema: 6 to 7%

• Striae in deep stroma

• Moderate edema: 10 to 15%

• Folds in deep stroma

• Severe edema: > 18%

• Central haze on sclerotic scatter

치료 / 처치법

• Increase Dk/L: higher water content, thinner design

• Looser fit for better tear exchange

Microcysts( 상피 미세낭종 ) / Vacuoles( 엑포 )

Microcysts( 상피 미세낭종 ) / Vacuoles( 엑포 )

• Microcysts are tiny cystic bodies containing cellular debris

• They form at the basal cells and slowly migrate towards the corneal surface

• They are visible with reversed illumination, indicating that the cystic material has a higher index of refraction than the surrounding corneal tissue

Microcysts / Vacuoles

Microcysts / Vacuoles

• Vacuoles form similarly to microcysts but are fluid filled

• They are visible with unreversed illumination, indicating that the cystic material has a lower index of refraction than the surrounding corneal tissue

Microcysts / Vacuoles

• Although they do not induce any symptomalogy, the presence of microcysts and vacuoles indicate a chronic hypoxic condition and a resulting alteration of corneal metabolism

• Removal of the offending contact lens will result in their disappearance over the course of several weeks

원인

• Several weeks (6 to 12 or more) of low Dk/L lens wear

• Extended Wear

증상 및 진단

• Small cysts in epithelium visible with retroillumination

• Microcysts: reversed illumination (higher index than cornea)

• Vacuoles: unreversed illumination (lower index than cornea)

치료 / 처치법

• Increase Dk/L

• D/C extended wear

• D/C lens wear if more than 50 are observed

• Monitor for 3 to 6 months for resolution– # may increase after d/c lens wear due to

abnormal processing of epithelial cells

Vascularization( 혈관신생 )

• Cellular debris and other metabolic by-products may be other stimuli to vessel growth

• Almost all soft lens patients will demonstrate some amount of vascularization

Vascularization( 혈관신생 )

Vascularization( 혈관신생 )

• In most cases, vascularization is asymptomatic, but encroachment into the visual axis may result in a reduction in vision

• Vascularization can be graded according to the number of quadrants and the extent to which the vessels have grown into the cornea

원인

• Long-term wear of any soft lens, but particularly lenses with low Dk/L (aphakic, prism ballasted, etc.)

• Extended wear

진단

• Varying degrees of vessels encroaching into previously avascular cornea– Grade 1: Sectorial or circumlimbal vessel

extension less than 0.5 mm, or 1 or 2 vessels extending less than 1.5 mm into cornea.

– Grade 2: Sectorial or circumlimbal vessel extension 0.5 to 1.5 mm into cornea.

치료 / 처치법

• Grade 1 or 2: monitor Q6mos• Grade 3: decrease wear time, increase Dk/L

or refit to RGP material• Grade 4: refit to RGP material or D/C lens

wear• Though vasc may regress, vessel walls do

not disappear– Watch for development of ghost vessels

Polymegethism( 폴리메가티즘 )

• A permanent condition of endothelial cell( 내피 ) change such that the cells are no longer uniform but are of varying sizes

Endothelial blebs( 내피 물집 )

• Transient, small, dark, non-reflective areas that appear shortly after lens insertion

원인

• Long-term wear of any soft lens, but particularly lenses with low Dk/L (aphakic, prism ballasted, etc.), extended wear

치료 / 처치법

• Change to higher Dk or RGP

• Monitor for further cellular changes, corneal edema

DRY EYE / DESICCATION

Soft Lens Desiccation( 탈수 )

• Soft lenses dehydrate when exposed to the atmosphere

• As the lens dehydrates, it draws water from the post-lens tear film, resulting in dryness of the cornea in these areas

• Tear flow dynamics from tight or high modulus soft lenses may contribute to this staining pattern

원인

• Thin, high water soft lens

• Borderline dry eye

• Extended wear

• Incomplete / infrequent blink

• Dry environment

• Heavy protein deposition

진단

• Inferior central arcuate punctate staining

치료 / 처치법

• Lubricating drops: unpreserved• Thicker lens design, prism ballast• Lower water content, non-ionic (group 1)• Lenses that have high water retention

(Proclear, Extreme H20, Soflens 66)• Frequent replacement (if deposited with

protein)• Punctal plugs

INFLAMMATION / INFECTION

Contact Lens-Induced Papillary Conjunctivitis (GPC)- 유두상결막염

• Typical symptoms– Itchiness– Stringy mucous discharge– Lens intolerance

• Hallmark sign is large papillae on the superior palpebral conjunctiva

• A combined immunological and mechanical response to denatured tear proteins that have adhered to the lens surface( 렌즈의 침전물에 의한 일종의 알레르기성 반응 )

원인

• Aged soft lens– high water content– ionic

• Aged rigid lens– silicone acrylate

• Poor compliance to cleaning regimen

• No enzymatic cleaning

증상

• Itchiness

• Mucous discharge: white ropy

• Lens awareness / intolerance

진단

• Large papillae on upper tarsal conjunctiva– SCL: diffuse distribution– RGP: more common along lid margin (zone 3)

• Heavily protein coated contact lens

• Poorly designed lens edge

• White, ropy mucous discharge

Diagnosis / Treatment: Stage 1

• Itching • Mucous discharge• Upper tarsus

hyperemic but relatively normal

• Discontinue lens wear or immediate refit in new lens

• Unpreserved lubricants

Diagnosis / Treatment: Stage 2

• Enlarged papillae on upper tarsus

• Hyperemic and edematous upper tarsal conjunctiva

• Increased itching and mucous

• Mild blurring of vision

• Reduced wear time• Discontinue lens wear • Unpreserved lubricants

Diagnosis / Treatment: Stage 3

• Large, clover-like papillae that may stain with fluorescein

• Increase in tarsal hyperemia

• Increased itching and mucous

• Lens discomfort

• Discontinue lens wear• Topical antihistamine• Topical vasoconstrictor• Topical NSAID• Refit to disposables or

RGPs

Diagnosis / Treatment: Stage 3

Diagnosis / Treatment: Stage 4

Diagnosis / Treatment: Stage 4

• Larger, more numerous papillae

• Exacerbation of symptoms

• Lens intolerance

• Discontinue lens wear• Topical steroid• Topical NSAID• Topical mast cell

stabilizer / combo• Refit to disposables or

RGPs

Contact Lens Superior Limbic Keratoconjunctivitis

Contact Lens Superior Limbic Keratoconjunctivitis( 상윤부각결막염 )

• Immunological response to lens surface deposits and solution preservatives

• Its superior location suggests that there may be a hypoxia component

• May also have a mechanical component

원인

• Soft contact lens wear

• Protein deposition

• Use of solutions containing thimerosal

증상

• Burning, itching

• Superior bulbar redness

• Photophobia, tearing

진단

치료 / 처치법

• Discontinue lens wear until resolution

• Lubricants

• Topical steroid if severe

• Refit to different material

• Patient education on compliance with lens care

• Discontinue use of thimerosal preserved solutions

Acute Red Eye/ 급성충혈 (Tight Lens Syndrome)

원인

• Extended wear of soft lenses, particularly tightly fitting lenses

• Extended wear of rigid lens with lens adherence

증상

• Awaken with unilateral discomfort or pain

• Redness

• Tearing

• Photophobia

진단

• Subepithelial infiltrates

• Conjunctival and limbal hyperemia

• Minimal epithelial staining

• Debris trapped between lens and cornea

치료 / 처치법

• Discontinue lens wear until infiltrates resolve

• Lubricants

• Prophylactic broad spectrum antibiotic drops if epithelial defect or infiltrates are present (fluoroquinolones, Polytrim)

• Change wearing schedule to daily wear

Case example

• 26 세 , 남• Sx of moderate irritation and localized

redness OD for 4 days

• No pain, discharge, photophobia, blurry vision

• SCL wearer for 10 years– Focus Monthly: replaces Q2mos– 16 hrs/day– Renu MPS

Sterile Infiltrate / Ulcer ( 무감염성 각막궤양 )

• An infiltrate is a localized collection of white blood cells

• An ulcer is an excavated area of the cornea that has undergone necrosis due to immunological or microbial invasion

원인

• Extended wear, long wear times

• Low Dk material

• Preserved solutions

• Poor compliance with care regimen

증상

• Mild irritation, tearing

• Foreign body sensation

• Localized bulbar redness

진단

• Peripheral, small diameter white subepithelial fuzzy lesions

• Overlying epithelial defect / disruption may be present

• Mild to moderate sectoral injection

• None to moderate anterior chamber reaction

치료 / 처치법

• Discontinue lens wear

• Culture if epithelial defect present: cannot diagnose as sterile until culture is done

• Artificial tears if no epithelial defect present

• Topical broad spectrum antibiotic if epithelial defect present– Fluoroquinolone (Ciloxan, Ocuflox) – Fortified aminoglycoside

• Continue antibiotic therapy until culture results are in, or until re-epithelialization– qh for 24 hours, then taper

• Topical steroid possible after re-epithelialization if infiltrates are

central and persistent

SOLUTION RELATED COMPLICATIONS( 보존액에

의한 부작용 )

Preservative Allergies and Sensitivities ( 방부제에

의한 앨러지 )

• Chemical care systems provide convenient disinfection with little damage to the contact lenses. However, many of the preservatives in use today are capable of inducing a Type IV delayed hypersensitivity response.

원인

• Long-term use of preserved soaking/rinsing solution

• Potential offending agents:– Polyquaternium-1 (Alcon)

– Polyaminopropyl biguanide (B&L)

– Polyhexamethylene biguanide (Allergan)

– Polyhexanide (Ciba)

– Chlorhexidine (Boston, Claris)

– Benzalkonium chloride (Allergan Wet n Soak)

– Thimerosal

증상

• Redness, itchiness, tearing

• Irritation with lens wear

진단

• Diffuse bulbar injection

• Diffuse SPK

• Possible subepithelial infiltrates

치료 / 처치법

• Discontinue lens wear if infiltrates or moderate to severe SPK are present

• Change preservative system or change to unpreserved care system

• If infiltrates persist after 2 weeks, consider a steroid

• Steroid Tx should be aggressive and of sufficient duration