Contact Lens Assessment Quiz

Baseline Measurements & Keratometry Feedback

• Patient eye level alignment is important

• Align the canthus

• Adjust the prescription for patient comfort

• Turn off lights during keratometry (Ks) procedure

• Keep hand on the joystick

• Meridians may not be at 180 and 90 degrees

• Record horizontal meridians first, then vertical

• Curvature and meridian not achieved

• Curvature achieved but meridian not achieved

• Curvature and meridian achieved

Baseline Measurements & Keratometry Feedback (Errors)

• Measuring not centered on the cornea
• Measurement too far to the left
• Measurement too far to the right

Introduction to Contact Lenses & History & Symptoms

• Introduction to contact lenses and history and symptoms overview

Lecture Outline – Introduction to Contact Lenses

• Brief history of contact lenses
• Types of contact lenses
• Benefits of contact lenses
• Advantages of scleral and rigid gas permeable lenses
• Contact lens parameters
• Contact lens fitting
• Contact lens fitting routine

Brief History of Contact Lenses

• Leonardo da Vinci's idea to alter corneal power
• Fluid-filled tube described by Rene Descartes
• Eye cup design of Thomas Young
• 'Animal jelly' sandwiched between a spherical capsule of glass and the cornea

Evolution of Contact Lenses

• Timeline of contact lens evolution, from glass lenses (1888) to silicone hydrogel lenses and beyond
• Key developments such as plastic (1948), silicone elastomer (1965), and disposable lenses (1994)
• Includes myopia control and photochromic technologies

Types of Contact Lenses

• Soft hydrogel lenses

• Silicone hydrogel lenses (SiHi)

• Rigid gas permeable (RGP) lenses

• PMMA lenses

• Hybrid lenses

• Daily disposable, biweekly disposable, monthly disposable, planned replacement lenses

• Prosthetic lenses

• Therapeutic lenses

• Scleral lenses

• Special effect lenses

Benefits of Contact Lenses Compared to Glasses

• Natural perception
• No edge blurring
• Better vision
• Larger field of view
• No fogging of the lens
• No weight or pressure on the nose
• Cosmetic appeal (appearance)

Advantages of SCL and RGP

• Soft lenses: easy insertion/removal, continuous wear up to 4 weeks
• Color change of the eyes possible in some cases
• Disposable lenses: no daily care necessary
• RGP lenses: stable optical imaging, excellent for high or irregular astigmatism, daytime Ortho-K

Contact Lens Fitting - Lens Parameters

• Edge thickness (t_p1, t_p2)

• Central thickness (tc)

• Back Surface Parameters (r₁, r₂)

• Base curve (SCL), BOZR (RGP)

• Front Surface Parameters (r_a1)

• FOZR

• BOZR

• Total diameter

• Various lens parameters(additional detail)

• Material

• Oxygen transmissibility (Dk)

• Water content (%)

Contact Lens Fitting – Lens Parameters (Additional)

• Various lens parameters with specific measurement designations
• Material types
• Oxygen transmissibility and water content percentages

ACLM Year Book

• Lists of disposable lenses
• Includes material details, water content, power details, UV protection, and optical design
• Listing the manufacturer and their details

Fitting Contact Lenses - Key Points

• Only registered optometrists, doctors, or contact lens opticians can fit contact lenses.
• Avoid occasional contact lens practice, especially in areas like therapeutic lens fitting.
• Discuss contact lens options with your patient(s) to support informed decisions.
• Provide the same care standard for all patients regardless of power or whether the lens has added power
• Patients with contact lenses must have had a recent sight test.

Fitting Contact Lenses – Key Things

• Document details
• Inform the patient of possible risks and benefits
• Document the information in the patient notes
• Avoid fitting yourself
• Advice and written info on lens care, cleaning, and maintenance.

Contact Lens Fitting - Routine

• Contact lens fitting routine

Information Needed for Lens Selection

• History and symptoms
• Baseline measurements
• Keratometry
• Anterior eye assessment
• Lens type
• Material
• Wearing modality
• Care system
• Refractive power
• Parameters
• Purpose
• Frequency
• Lifestyle
• Environment
• Motivation
• Ocular condition
• Refractive error

History and Symptoms

• Introduction to history and symptoms taking
• Importance of H&S
• Indications and contraindications of CL wear
• The Case History
  • Asking questions: new and existing contact lens wearers
• Patient Education (information for patients)
• Record Keeping

What is History and Symptoms?

• Purpose: determine suitability for contact lens wear
  • Analyze patient specifics for indications and contraindications
  • Risk/ benefit assessment for individual prescriptions
  • Provide initial information for contacts, and education, about lens suitability.

Why is H&S Important?

• Detailed history for future decisions
• Thorough and documented examination needed.
• Understanding expected findings during examination
• Forming a structure for examination procedures
• Insight to manage the patient

Indications & Contraindications of Contact Lens Wear

• Patient age
• Anatomical factors
• Ocular health
• General health
  • Allergies (specifics)
  • Chronic infection
  • Metabolic disorders
  • Pregnancy, lactation, hormonal changes
  • Systemic medication
  • Psychological factors (motivation, lifestyle)
  • Lifestyle/ occupational issues
  • Financial considerations

Effects of Aging on the Eyes

• Decreased palpebral aperture
• Decreased lacrimal secretion
• Reduced tear stability
• Decreased tonus of upper and lower eyelids
• Increased glare sensitivity
• Reduced CS
• Effects from systemic drugs
• Corneal changes
• Ocular media changes
• Increased pupil diameter

Possible Effects of Systemic Medications & General Health Status on Contact Lens Wear

• Specific types of medications and potential problems for each condition.
• Advice for managing potential issues while wearing contact lenses.

The Case History – Asking the Questions

• Build rapport with the patient
• Utilize open-ended questions
• Understand how the information will assist
  • In selecting the correct lens
  • Helping in future monitoring
• Keep eye contact
• Explain procedure during the duration of the consultation
• Informed decisions made

The Case History – Non-Contact Lens Wearers

• Reason for visit
• Previous contact lens use
• Ocular health (current RX, power, onset, wearing habits, eye conditions, vision problems, surgeries, infections, GP/hospital visits)
• General health (allergies, diabetes, thyroid problems, systemic inflammatory conditions, skin conditions)

The Case History – Non-CL Wearers (additional information)

• Medications (type, frequency, dosage)
• Lifestyle factors (occupational and social)
• Expectations (why they want CLs, wearing frequency, duration, and budget)

The Case History – Existing Contact Lens Wearers

• Questions for existing contact lens wearers (similar to new patient, with additional questions)
  • Type of lens they are currently using
  • Date of last fitting
  • Changes in lens type
  • Modalities of wear
  • Frequency of replacement
  • Care system utilized

Evaluation of Symptoms

• Symptoms related to contact lens wear
• Possible causes for symptoms
• Action to be taken in response

Patient Education

• Reiterate findings from the case history
• Inform the patient of the benefits of CL
• Inform of the risk of noncompliance
• During the assessment, inform the patient of procedures
  • Purpose and what can be expected.
• Provide and explain options

Daily Decision Tree for Contact Lens Wearers

• Daily self-assessment (redness, pain, blurring, tearing, etc.)
• Addressing warning signs
• Actions based on daily assessment (removal, consult, care, etc.)

Record Keeping

• Outline for record keeping, including crucial details for new patients. Specific information to be recorded for initial patient appointments.)

RGP Insertion and Removal

• Detailed procedure explanation

RGP Insertion

• Pre-insertion steps: cleaning hands and lenses, explain what to expect
• Conditioning solutions use

RGP Fitting

• Allow the lens to settle for 15 minutes before evaluating fit

RGP Removal

• RGP removal procedure

Questions

• Questions section

Recommended Reading

• List of recommended reading materials
• Author, title, and information related to books and handbooks.

Acknowledgments

• List of individuals and organizations acknowledging the contribution to the content of the lecture

Test your knowledge on the essential factors involved in assessing prospective contact lens wearers. This quiz covers patient history, initial assessments, and education about contact lens use. Understand the implications of various conditions and treatments on contact lens fitting and wear.