Solution Related Complications and Mechanical Complications

What are preservative allergies and sensitivities in contact lens wear?

A Type IV delayed hypersensitivity response caused by preservatives in chemical care systems

What is the advantage of chemical care systems for contact lenses?

They provide convenient disinfection with little damage to the lenses

What preservatives can cause hypersensitivity reactions?

Polyquaternium-1, polyaminopropyl biguanide, polyhexamethylene biguanide, polyhexanide, chlorhexidine, benzalkonium chloride, and thimerosal

What history is associated with preservative allergies?

Long-term use of preserved soaking or rinsing solutions

What are the symptoms of preservative allergies?

Redness, itchiness, tearing, and irritation with lens wear

What are the diagnostic signs of preservative allergies?

Diffuse bulbar injection, diffuse SPK, and possible subepithelial infiltrates

How are preservative allergies treated?

Discontinue lens wear if severe, change to unpreserved system, and consider steroids if infiltrates persist

What is chemical toxicity in contact lens wear?

An immediate toxic reaction caused by substances damaging epithelial cells

What is the main cause of chemical toxicity?

Improper use of contact lens care systems

What history is associated with chemical toxicity?

Inadequate rinsing, hydrogen peroxide misuse, enzymatic cleaner residue, and poor hand hygiene

What are the symptoms of chemical toxicity?

Immediate burning, stinging, redness, tearing, and photophobia

What are the diagnostic signs of chemical toxicity?

Diffuse SPK and diffuse bulbar injection

How is chemical toxicity treated?

Discontinue lens wear, irrigate the eye, use lubricants, give antibiotics if severe, and re-educate the patient

What are pseudodendrites?

Dendriform epithelial lesions usually caused by thimerosal sensitivity

What history is associated with pseudodendrites?

Soft lens wear and use of thimerosal-preserved solutions

What are the symptoms of pseudodendrites?

Mild to moderate irritation

What are the diagnostic features of pseudodendrites?

White branching epithelial lesions that stain with fluorescein and lack terminal bulbs or Rose Bengal staining

How are pseudodendrites treated?

Discontinue lens wear, use lubricants, refit lenses, and switch to unpreserved solutions

What is abrasion or foreign body tracking in contact lens wear?

Damage to the corneal epithelium caused by particles trapped under the lens

What increases infection risk in contact lens-related abrasions?

Greater chance of gram-negative infection due to ocular flora differences

What history is associated with abrasion or foreign body tracking?

Foreign particles, RGP wear, trauma, insertion/removal injury, or keratoconus with flat lens

What are the symptoms of corneal abrasion from contact lenses?

Asymptomatic to mild sharp pain

What are the diagnostic signs of abrasion?

Linear, jagged staining patterns and patchy epithelial defects

How are minor abrasions managed?

No treatment or optional lubricants

How are moderate to severe abrasions managed?

Discontinue lens wear, use lubricants, and give prophylactic antibiotics

How are large abrasions treated?

Use bandage lens with antibiotics, avoid patching, and follow up within 24 hours

What is dimple veiling?

Superficial fluorescein staining caused by epithelial indentations from trapped air bubbles

What causes dimple veiling?

Air bubbles and excessive tear pooling under a poorly fitting lens

What history is associated with dimple veiling?

Poorly fitting RGP or SCL and irregular cornea such as keratoconus

What are the symptoms of dimple veiling?

Usually none, but may cause blurry vision if central

What are the diagnostic signs of dimple veiling?

Dot staining, air bubbles under lens, and poor tear exchange

How is dimple veiling treated?

It resolves after lens removal and requires refitting to improve tear pump

What is lens adhesion?

An immobile contact lens caused by poor fit or tear film issues

What factors contribute to lens adhesion?

Poorly fitting lenses, dry eye, and poor tear film quality

What are the symptoms of lens adhesion?

Stuck lens, difficult removal, blurry vision, redness, irritation, and reduced wear time

What are the diagnostic signs of RGP lens adhesion?

Immobile lens, debris under lens, poor tear pump, lens imprint, and epithelial staining

What are the diagnostic signs of SCL lens adhesion?

Immobile lens, debris, conjunctival imprint, staining, and distortion on topography

How is lens adhesion treated?

Discontinue lens wear, use lubricants, give antibiotics if needed, and refit lenses

What is superior epithelial arcuate lesion?

An acute splitting of the corneal epithelium due to chronic mechanical stress

What factors contribute to superior epithelial arcuate lesion?

Tight soft lenses, thick lens edges, low Dk, and tight upper eyelid

Where is superior epithelial arcuate lesion typically located?

In the superior cornea parallel to the limbus

What history is associated with superior epithelial arcuate lesion?

Long-term soft lens wear and extended wear

What are the symptoms of superior epithelial arcuate lesion?

Usually none or mild irritation, burning, itching, and redness

What are the diagnostic signs of superior epithelial arcuate lesion?

Linear epithelial break staining with fluorescein in the superior cornea

How is superior epithelial arcuate lesion treated?

Discontinue lens wear, use lubricants, and refit to higher Dk and better fitting lenses

What causes RGP discomfort related to position?

Low-riding lens, interpalpebral fit, and decentration

How can RGP lens position issues be corrected?

Improve lid attachment, steepen fit, or use aspheric or toric designs

What factors affect RGP lens movement and stability?

Base curve, lens diameter, optic zone diameter, edge design, and peripheral curves

What edge factors contribute to RGP discomfort?

Edge configuration, contour, profile, and edge lift

What psychological factors influence RGP comfort?

Expectations, communication, technique, and adaptation

What causes SCL discomfort with a flat base curve?

Immediate discomfort, excessive movement, decentration, and edge ripple

How is flat SCL fit corrected?

Steepen base curve and increase lens diameter

What causes SCL discomfort with a steep base curve?

Initial comfort followed by tight lens, reduced movement, debris trapping, and difficult removal

How is steep SCL fit corrected?

Flatten base curve and decrease lens diameter

What lens defects can cause SCL discomfort?

Inside-out lens, edge chips, cracks, holes, and fractures

What causes blurry vision with rigid lenses due to residual cylinder?

Corneal or internal astigmatism

What causes blurry vision from lens flexure or warpage?

Changes detected by keratometry, radiuscope, or lensometry

What causes fluctuating vision with rigid lenses?

Lens movement, instability, or toric rotation

What causes cloudy vision with rigid lenses?

Steep fit, surface drying, or corneal edema

What causes flare with rigid lenses?

Decentration, optic zone issues, or poor curve blending

What causes spectacle blur with rigid lenses?

Corneal edema or corneal molding

What causes blurry vision with soft lenses due to residual cylinder?

Astigmatism up to 0.75 DC or toric lens instability

What causes fluctuating vision with soft lenses?

Lens movement, toric rotation, or poor draping of a steep lens