PCL Lab IV

If a patient seeks CLs due to family/ friend encouragement motivation will be ___, and success _______.

• low; reduced

  • realized prior to fitting, less likely disillusioned later

pregnancy & CLs

• ocular changes can affect lens fit and comfort

allergies/ high fevers and CLs

• uncomfortable during allergy attacks

• med allergies: may have rxn to solutions for CLs

Specific CL fitting exam procedures

1. va

2. refraction

3. binocularity/ near point problems

4. corneal curvature

5. SLE

SLE emphasis for cl fitting

• eyelids, margins, and lid eversion

• MacDonald’s Tear Observation

• TBUT

• corneal staining

• conjunctiva and cornea

Ocular dimensions to measure

• blink rate and type

• palpebral aperture

• lid to cornea relationship

• lid tension

• corneal diameter

• pupil size

• corneal thickness

blink rate and type

• record blinks per minute

• record if blinks full or partial

palpebral aperture measurement

• lids in normal relaxed position

  • patient closes eye when PD ruler touches lashes or if patient anticipates getting hit

• pt focused at object at level in front of them

• examiner at eye level w/ pt measuring at middle of lid opening

observe and draw lid to cornea relationship

• position of lid margin w/ respect to the cornea

• measuring upper lid in relation to upper limbus and lower lid in relation to lower limbus

• pt relaxed looking straight ahead

lid tension

• estimated when everting the lids

• loose, average, or tight

  • elderly: loose/ flaccid

  • orientals: thick/ tight

corneal diameter

• VID: visible iris diameter (mm)

• pt looks straight ahead, examiner hold pts upper lid, measured directly in front of pt

• Horizontal avg: ~11.7mm

• Vertical avg: ~10.7mm (not typically measured)

pupil size

• indicates type and size of CL

• to predict visual problems (blur from lens edge in low illumination)

• measured in avg. light conditions

corneal thickness

• direct measurement of corneal swelling/ edema

• pachometer: SL attachment to measure corneal thickness

Other tests for cl fitting

• ophthalmoscopy

• VF screening

• CV

• stereoacuity

• corneal sensitivity

• ocular smears

• Schirmer tear test

• photography

Indications for Hard CLs

• astigmatism: provide superior and constant high level of visual performance

• environmental factors: hot/ dry climate, A/C, fluctuating environments

• aphakic: easier to handle

• less expensive

• more durable

• inadequate tear production: maintain hydration of hydrophilic lenses

Indications for SCLs

• rapid adaptation: those with lower threshold for discomfort

• intermittent wear

• athletes: less mechanical damage to eye

• wide palpebral fissures: more comfort

contraindications to CL wear

• low motivation

• poor hygiene

• mental conditions impacting careful management and hygiene

• corneal disease

• occupational environments: hair dresser, car mechanic. chemical worker

• lid conditions: chalazion, blepharitis

• systemic conditions: DM, respiratory diorders, endocrine changes