General Problem-Solving

Symptoms

• Vision varies with blink
• Lens awareness

Causes

• Decentered corneal apex or ATR astigmatism
• Tight or loose lid tension
• Thick lens design
• High specific gravity material
• Unusual corneal topography. (Beware of superior flattening and inferior steepening shown in topography for long-term wear of superior positioning GP.)

Diagnosis

• Biomicroscopic evaluation during and after blink: see excessive movement with blink or simply stays in a decentered position. Patient views through non-optical periphery of lens, often intermittently.

Management

Inferior Decentration

• (+) lenticulate if power >-5.00
• (-) lenticulate if power <-1.50
• (-) lenticulate all + lens
• Bitoric for >2.50 cylinder
• Lid attachment design
• Flatter BCR
• Minimize CT
• Lower specific gravity material

Superior Decentration

• Plus lenticular
• Increase CT
• Steepen BCR

Lateral Decentration

• Larger overall diameter
• Steeper BCR
• Aspheric design

Symptoms

• Lens awareness
• Occurs in more than 50% of rigid lens wearers

Causes

• Dryness
• Lid margin disease (Meibomianitis) and blepharitis can compromise tear film

Diagnosis

• Phenol Red Thread <10mm or T.B.U.T. <6 sec limits wearing time
• 3 and 9 o'clock punctate staining
• Severity range from diffuse punctate staining to corneal opacification and neovascularization

Management

• If staining coalesced, improve centration
• Decrease edge lift (consider aspheric design or steepen PCR & PCW)
• Change to F-S/A material
• Ensure proper blinking & frequency
• Frequent use of rewetting drops
• Lid hygiene
• Hot compresses with gentle lid massage for meibomian gland dysfunction
• Humidifier