4.1 CL IV - Preliminary Exam Flashcards
What are the 4 basic steps of getting a patient contact lenses? What is the possible extra step?
- Full eye test + Preliminary examination
- Contact lens fitting
- Contact lens delivery/ teach
- Contact lens aftercare
- Contact lense refit → px may need to come back again if the CLs were found to be unsuitable
What are the purposes of preliminary examination?
- Inform px about CLs: set px expectations & confirm px’s decision to proceed with CLs;
- Obtain baseline information → topography, anterior eye conditions, purpose;
- Assess px suitability/ compliance with CLs hygiene
What are the important information that we should inform the patient about contact lenses?
- Types of CLs available & their limitations: SDL vs RGP; lens replacement schedule/ modality; wearing schedule (hours per day? Overnight?);
- CL hygiene & care
- Having CLs doesn’t exclude the need for spectacles
- Fit & Rx for CLs takes 1-3 appointments
- Cost of appointments
- Need for aftercare appointments every 6 months/ annually
- Insertion, removal time + hygiene + commitment will need to be factored into px’s daily routine
- Adaptation period: gradual wearing in, FB sensation, dry eye, photophobia, glare, magnification issues
- Reduced protection from FB provided by spectacles
- Many people are highly successful CL wearers with proper behaviours and Rx
Answer these common questions from px:
1. Do they hurt?
2. Is it difficult for me to put the lens in?
3. How long does it take to get used to them?
4. Can I sleep in them?
5. Can I swim in them?
6. Will they fall out?
7. Will they disappear behind my eyes?
8. How much will they cost?
9. Will they change the colour of my eyes?
- No, unless there’s an infection, inflammation or allergic rxtn, which px should come back for an appointment;
- No (reassure px)
- About a week or two to get used to them;
- Can only sleep in them if it was designed to
- Can only swim in them if it was designed to
- Yes, they will fall out when they are dried out and lose their shape
- With the anatomy of the eye and conjunctiva, they do not go behind your eye, they can always be taken out
- Same costs as glasses
- Only change colour if px wants them to and if the CLs are designed to
What are the 5 basic preliminary CL workup procedures?
- Complete Hx (+ CL Hx)
- Refraction (account for vertex distance)
- External eye examination (ocular parameters)
- Slit lamp biomicroscopy (DE symptoms, allergies)
- Keratometry/ Corneal topography
What are the specific questions needed to be asked in a contact lens history?
- Px’s motivation
- Intended wearing time
- Intended wearing activity
- Ocular Hx
- Occupation
- Sytemic/ allergy Hx
- Medication (some medications can cause dry eye: oral contraceptives, anti-depressants, rosacea, acne)
What are the 5 ocular parameters needed during CLs preliminary examination?
- Corneal diameter (HVID = horizontal visible iris diameter)
- Pupil diameter at low illumination
- Palpebral aperture
- Lids tight/flaccid; high/low
- Corneal sensitivity
What are the 3 important techniques needed during slit lamp biomicroscopy for a CL preliminary assessment?
- Lid eversion
- Fluorescein staining
- TBUT
What are the personal indications of getting CLs? What are the personal contraindiacations?
Indications:
* cosmetic reasons,
* highly motivated px,
* sport,
* occupation,
* large refractive error
Contraindications:
* environment,
* occupation,
* low refractive error,
* monocular wear (only have one eye, high risk),
* poor hygiene,
* poor manual dexterity,
* sensitive eyes,
* poor motivation
What are the ocular indications of getting CLs?
- High refractive error
- Anisometropia
- Aphakia
- Trichiasis
- DED
- Exposure keratitis
- Nystagmus (kids)
- Therapeutic bandage CLs → recurrent erosions, bulbous keratopathy
- Ocular disfigurement
- Unsuccessful refractive surgery
- Post-keratoplasty
- Keratoconus
- Children, self esteem/ myopia control
What are some of the concerning ocular conditions that we have to carefully manage if px wants CLs?
- Cosmetically noticeable strabismus
- Conjunctivits
- Dry eye
- Glaucoma
- Hx of keratitis
- Ocular allergies
- Decrease corneal sensitivity
- Pingueculae → Pterygium
- Lid conditions
- Uveitis
What are the 9 systemic factors that can influence CL wear?
- If general health is poor, tolerance to CLs may be reduced;
- Smoking can exacerbate dry eyes and produce particulate matter;
- Chronic sinusitis increases mucous in tears, thus causing more lens deposits;
- Allergies, such as hayfever, increases risk of poor tolerance, hypersensitivity to solutions/ CL materials etc.;
- Skin problems, such as acne rosacea and atopic eczema, can increase irritation with CL use, thus reduce tolerance;
- Endocrine changes can exacerbate dry eyes;
- Thyroid disease can cause dry eyes, exophthalmos, reduced blinking and reduced tear flow;
- Pregnancy can cause a less stable tear film;
- Use of topical medication can influence CLs use
Px who has ... and wears contact lenses is more likely to be associated with ..., dry eyes, ... and reduced healing rate, higher risk of ..., ... refraction, and reduced .... Due to increased risks of theses conditions, px with diabetes should not ` be fitted as an … (… with CLs). We should ensure we pick CL materials that …. to the …. We must also … and ensure px is … with proper …`
Px who has diabetes and wears contact lenses is more likely to be associated with blepharitis, dry eyes, epithelial fragility and reduced healing rate, higher risk of keratitis, unstable refraction, and reduced corneal sensitivity. Due to increased risks of theses conditions, px with diabetes should not be fitted as an extended wear (sleeping overnight with CLs). We should ensure we pick CL materials that maximise O2 supply to the cornea. We must also closely monitor and ensure px is compliant with proper CL hygiene and care
