Contact Lens Handling and Care
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Questions and Answers

How should you dry your hands after washing and rinsing them before handling contact lenses?

  • With a dirty cloth
  • With a regular towel
  • With a paper towel
  • With a lint-free towel (correct)

    • What should you do before placing the contact lens on your eye?

  • Wipe the lens with a dry cloth
  • Soak the lens in hot water
  • Rinse the lens with sterile water
  • Rinse the lens with a multipurpose solution or sterile saline (correct)

    • Why should you gaze upwards into a mirror when inserting contact lenses?

  • To make it easier to insert the lens
  • To maximize exposure of the inferior bulbar conjunctiva (correct)
  • To see the lens better
  • To get a better view of your eye

    • How should you remove the contact lens from your eye?

    <p>By sliding the lens downwards with your index finger</p> Signup and view all the answers

    Why should you open your mouth as wide as possible when inserting contact lenses?

    <p>To reduce the ability to blink</p> Signup and view all the answers

    What should you do with the contact lens after removal?

    <p>Clean and rinse the lens with the habitual solution</p> Signup and view all the answers

    Why should you insert contact lenses before applying cosmetics?

    <p>To avoid trapping debris under the lens</p> Signup and view all the answers

    What is a common mistake to avoid when inserting contact lenses?

    <p>Trapping air bubbles under the lens</p> Signup and view all the answers

    What is the equivalent of 45.00D in millimeters for the base curve radius of a corneal GP lens?

    <p>7.50mm</p> Signup and view all the answers

    What is the purpose of placing a drop of water or hydrogel multipurpose solution in the depression on the concave lens mount?

    <p>To prepare the radioscope for measurement</p> Signup and view all the answers

    What should you do if the solution on the concave lens surface distorts the target's appearance?

    <p>Continue with the measurement as long as the 'spokes' are visible</p> Signup and view all the answers

    How do you 'zero out' the inner and outer scales using the radioscope?

    <p>Using the knurled knob</p> Signup and view all the answers

    What do you see when you bring the target into focus using the fine adjustment knob?

    <p>The image of the light bulb filament</p> Signup and view all the answers

    How do you record the base curve radius using the radioscope?

    <p>Read the smaller inner dial first and then the larger outer dial</p> Signup and view all the answers

    What is the increment marked on the larger outer dial of the radioscope?

    <p>0.01mm</p> Signup and view all the answers

    What should you do if the pointer lies between two numbers on the smaller inner dial?

    <p>Use the smaller number</p> Signup and view all the answers

    When recording the BCR, what precision should be used?

    <p>0.01mm</p> Signup and view all the answers

    What is the purpose of using a small aperture lens stop?

    <p>To provide a clearer target</p> Signup and view all the answers

    How should the Center Thickness be measured?

    <p>With a dedicated thickness gauge or the gauge on the radioscope</p> Signup and view all the answers

    What is the typical range of Center Thickness for minus power lenses?

    <p>0.10-0.20mm</p> Signup and view all the answers

    How is the Overall Diameter measured with a lens loupe?

    <p>By centering the lens above and below the scale</p> Signup and view all the answers

    What is the purpose of multiplying the Peripheral Curve System width by 2?

    <p>To calculate the total width of the PCS relative to the OAD</p> Signup and view all the answers

    What is the term for the smoothing of the junction between the OZD and each PC?

    <p>Blend</p> Signup and view all the answers

    How are blends classified?

    <p>By the difficulty of seeing the junctions between the curves</p> Signup and view all the answers

    What is the purpose of the black dot on the periphery of a patient's right lens?

    <p>To indicate the right or left lens</p> Signup and view all the answers

    What is the critical step in taking a BCR measurement?

    <p>Sharpening the target lines 90° apart</p> Signup and view all the answers

    How should the BCRs of Bitoric (SPE/CPE) and Front Sphere/Back Toric GP lenses be recorded?

    <p>With the steepest one first and the flattest one second, separated by a slash</p> Signup and view all the answers

    How should the Powers of Bitoric (SPE/CPE) and Front Sphere/Back Toric lenses be recorded?

    <p>With the greatest minus or least plus power first and the least minus or greatest plus power second, separated by a slash</p> Signup and view all the answers

    How should the power of a Front Toric/Back Sphere lens be recorded?

    <p>With the sphere, cylinder, and axis, separated by commas</p> Signup and view all the answers

    What is the purpose of calculating the ratio of the difference between radioscope readings and lensometry readings?

    <p>To determine the type of toric GP lens</p> Signup and view all the answers

    What is the identifying feature of a Front Toric/Back Sphere lens?

    <p>Prism Ballast and Truncation</p> Signup and view all the answers

    How should the ratio of the difference between radioscope readings and lensometry readings be calculated?

    <p>By dividing the larger number by the smaller number</p> Signup and view all the answers

    What is the identifying feature of a Bitoric (CPE) lens?

    <p>Any ratio other than 1:1 or 1:1.4</p> Signup and view all the answers

    What is the identifying feature of a Back Toric/Front Sphere lens?

    <p>1:1.4 ratio</p> Signup and view all the answers

    What is the primary purpose of using Addipak inhalation saline?

    <p>To mimic the body's natural tears for scleral lens, hybrid and gas permeable contact lenses</p> Signup and view all the answers

    What is the correct way to re-center a decentered corneal GP CL?

    <p>Use a drop of GP multipurpose solution, conditioner, or lubricant and gently manipulate the CL to the center of the cornea using the lids</p> Signup and view all the answers

    What should you avoid using when washing your hands before handling contact lenses?

    <p>Lotion and perfumed soaps</p> Signup and view all the answers

    What is the purpose of placing a drop of GP multipurpose solution or conditioner on the posterior surface of the CL before insertion?

    <p>To cushion the impact of the CL on insertion</p> Signup and view all the answers

    What should you do if you experience immediate discomfort after inserting a corneal GP CL?

    <p>Look down to decrease awareness of the CL</p> Signup and view all the answers

    Why should you retract the right lower lid at the lid margin with the right middle finger during CL insertion?

    <p>To prevent reflex blinking and eye movement</p> Signup and view all the answers

    What is the primary purpose of using saline in contact lens care?

    <p>To rinse away debris and break up loosely adherent deposits</p> Signup and view all the answers

    What is the key advantage of using hydrogen peroxide systems in contact lens care?

    <p>They have good anti-microbial activity without the need for preservatives</p> Signup and view all the answers

    What is the recommended order of lid release during CL insertion?

    <p>Inferior lid first, then superior lid</p> Signup and view all the answers

    What is the Lid Margin Technique used for in CL removal?

    <p>To remove the CL</p> Signup and view all the answers

    What is the recommended frequency of use for B & L Boston One Step Liquid Enzymatic Cleaner?

    <p>Weekly</p> Signup and view all the answers

    What is the purpose of using a clean, flat surface when preparing to handle contact lenses?

    <p>To prevent damage to the CL</p> Signup and view all the answers

    Which of the following contact lens care products is FDA-approved for rinsing and filling the bowls of scleral contact lenses?

    <p>Menicon Lacripure</p> Signup and view all the answers

    What should you do with the CL after removal and inspection for damage?

    <p>Clean the CL with a habitual solution and store it hydrated in the case</p> Signup and view all the answers

    What is the primary reason for disposing of storage cases monthly?

    <p>To prevent contamination</p> Signup and view all the answers

    What is the purpose of rewetting drops in contact lens care?

    <p>To make the surfaces of contact lenses more hydrophilic</p> Signup and view all the answers

    What is a key advantage of one-bottle multipurpose care systems?

    <p>They are easier to use</p> Signup and view all the answers

    What is a potential disadvantage of using chemical systems for contact lens care?

    <p>Some patients may be sensitive or allergic to the preservatives used</p> Signup and view all the answers

    What is the purpose of Menicon Progent?

    <p>To remove protein deposits from contact lenses</p> Signup and view all the answers

    Why are GP lubricants not compatible with hydrogel contact lenses?

    <p>They are incompatible with the material</p> Signup and view all the answers

    What is the primary reason why daily cleaning of GP lenses is necessary?

    <p>To remove loosely adherent deposits and debris</p> Signup and view all the answers

    What is the function of a conditioner in GP lens care?

    <p>To act as a buffer between the lens and the cornea</p> Signup and view all the answers

    Why are silicone acrylate materials more prone to protein deposits than fluorosilicate acrylate materials?

    <p>Because they have a greater affinity for protein</p> Signup and view all the answers

    What is the primary function of a daily protein remover and periodic enzymatic cleaner?

    <p>To remove protein deposits from the lens</p> Signup and view all the answers

    Why are higher viscosity conditioners more effective for providing comfort?

    <p>Because they provide a greater cushioning effect</p> Signup and view all the answers

    What is the primary function of a lubricant in GP lens care?

    <p>To lubricate the lens during handling</p> Signup and view all the answers

    Why do GP CLs require less frequent cleaning and disinfection than hydrogel CLs?

    <p>Because they don't promote the growth of microorganisms in situ</p> Signup and view all the answers

    What is the primary difference between abrasive and surfactant cleaners?

    <p>Abrasive cleaners contain particulate matter that's more effective for deposit removal</p> Signup and view all the answers

    What is the primary advantage of using a Burton Lamp compared to a slit lamp for fitting corneal GP CLs?

    <p>Portability</p> Signup and view all the answers

    What is the minimum vertical movement required for sufficient tear exchange in corneal GP CLs?

    <p>1.0mm</p> Signup and view all the answers

    What is the recommended BCR selection for a corneal cylinder of 2.25D?

    <p>0.25D STK</p> Signup and view all the answers

    What is the purpose of converting the BCR written on a diagnostic CL flat pack or vial from millimeters of curvature to diopters?

    <p>To select the initial BCR</p> Signup and view all the answers

    What is the characteristic of movement in a Modified Lid Attachment (MLA) fitting philosophy?

    <p>Moves up and down with lid movement, and then lags</p> Signup and view all the answers

    What is the acceptable range of decentralization in a corneal GP CL fit?

    <p>As long as the OZD covers the pupil</p> Signup and view all the answers

    What is the purpose of assessing the centration of a corneal GP CL?

    <p>To ensure optimal vision</p> Signup and view all the answers

    What is the recommended BCR selection for a corneal cylinder of 0.50D?

    <p>0.25D FTK</p> Signup and view all the answers

    What is the advantage of using a lower magnification setting on a slit lamp for evaluating corneal GP CLs?

    <p>To see the 'forest for the trees'</p> Signup and view all the answers

    What is the recommended action if there is visual fluctuation, glare/halos, or conjunctival or limbal staining in a corneal GP CL fit?

    <p>Modify the fit</p> Signup and view all the answers

    What does black represent in fluorescein patterns?

    <p>Areas of bearing</p> Signup and view all the answers

    What is the goal of fluorescein pattern evaluation in contact lens fitting?

    <p>To achieve an even pattern with minimal clearance in the center and mid-periphery and moderate clearance in the periphery</p> Signup and view all the answers

    What happens when you steepen the BCR of a GP lens?

    <p>The fit is tightened</p> Signup and view all the answers

    What is the equivalent power change for a 0.10mm change in BCR in a GP lens?

    <p>It depends on the BCR range</p> Signup and view all the answers

    What should you do when making SAM FAP equivalent power changes for GP lenses with very steep BCR?

    <p>Convert BCR to Diopter power readings prior to making power changes</p> Signup and view all the answers

    What is the purpose of assessing fluorescein patterns in contact lens fitting?

    <p>To assess the fit of the lens</p> Signup and view all the answers

    What does the acronym MAC stand for in contact lens fitting?

    <p>Minimal Apical Clearance</p> Signup and view all the answers

    What is the term for an even pattern of fluorescein centrally?

    <p>Alignment</p> Signup and view all the answers

    What happens when you flatten the BCR of a GP lens?

    <p>The fit is loosened</p> Signup and view all the answers

    What is the purpose of evaluating the mid-periphery in fluorescein patterns?

    <p>To evaluate the fit of the lens</p> Signup and view all the answers

    What is the effect of increasing the OAD by 0.5mm on the fitting relationship?

    <p>It will steepen the fit</p> Signup and view all the answers

    What is the effect of flattening the BCR by 0.05mm on the SAM FAP?

    <p>It will create a minus tear layer</p> Signup and view all the answers

    What is the purpose of modifying the OZD in concert with the OAD?

    <p>To maintain the same fitting relationship</p> Signup and view all the answers

    What is the effect of increasing the PCR by 1.0mm on the peripheral clearance?

    <p>It will increase the peripheral clearance</p> Signup and view all the answers

    What is the smallest significant change in OAD?

    <p>0.5mm</p> Signup and view all the answers

    What is the effect of a steep cornea on the OAD trend?

    <p>It will trend towards a smaller OAD</p> Signup and view all the answers

    What is the purpose of modifying the PCR in 1.0mm increments?

    <p>To widen the peripheral curve radius</p> Signup and view all the answers

    What is the effect of increasing the OAD on the refractive error?

    <p>It will decrease the hyperopic refractive error</p> Signup and view all the answers

    What is the purpose of flattening the BCR by 0.05mm when increasing the OAD?

    <p>To maintain the same fitting relationship</p> Signup and view all the answers

    What is the effect of increasing the OZD on the pupil size?

    <p>It will have no effect on the pupil size</p> Signup and view all the answers

    Study Notes

    Preparation

    • Wash hands thoroughly with non-lotion and non-perfumed soap, then dry with a lint-free towel.
    • Remove the right lens from storage and rinse with multipurpose solution or sterile saline.
    • Inspect the lens for damage and eversion by placing it on the tip of the right index finger.

    Insertion

    • Use an upright mirror to gaze upwards, lowering the chin to the chest.
    • Expose the inferior bulbar conjunctiva by retracting the right lower lid at the lid margin with the right middle finger.
    • Retract the right upper lid at the lid margin with the left middle finger.
    • Place half the lens on the cornea and half on the inferior bulbar conjunctiva.
    • Lower the eyes downwards, and then release the lids slowly.

    Removal

    • Wash, rinse, and dry hands as previously described.
    • Use an upright mirror to gaze upwards, lowering the chin to the chest.
    • Retract the right lower lid at the lid margin with the right middle finger.
    • Slide the lens downwards with the right index finger, placing half on the cornea and half on the bulbar conjunctiva.
    • Pinch the lens lightly between the thumb and index finger to break the suction, and then remove from the eye.
    • Inspect the lens for damage, clean, and rinse with the habitual solution before putting it in the case.

    Tips for Insertion and Removal

    • The lens can be placed directly on the cornea.
    • Opening the mouth wide can reduce excessive blinking during insertion.
    • Insert lenses before applying cosmetics to minimize debris trapping.
    • Use multipurpose solution or soft lens compatible rewetting drops to aid in difficult lens removal.

    Cleaning

    • Perform digital rubbing on the anterior lens surface by placing it in the non-dominant hand, adding the suggested number of drops, and rubbing back and forth and/or side to side.
    • Repeat the process for the posterior lens surface, avoiding hard rubbing that can tear thinner lenses.

    Base Curve Radius (BCR)

    • BCR can be written in either dioptric power or millimeters (e.g., 45.00D = 7.50mm)
    • Measured using a radioscope (e.g., Marco Radiusgauge)
    • Procedures to measure BCR:
      • Prepare the lens by cleaning, rinsing, and patting it dry
      • Prepare the radioscope by placing a drop of water or hydrogel multipurpose solution on the concave lens mount
      • Place the lens in the well on the lens mount and center it on the stage
      • Use the coarse adjustment knob to raise the objective until the target form appears
      • Move the stage to center the target and bring it into focus using the fine adjustment knob
      • "Zero out" the inner and outer scales using the knurled knob
      • Record the BCR to the nearest 0.01mm

    Power (F)

    • Verified using a lensometer
    • Measured in the customary manner
    • Power in Bitoric and Front Sphere/Back Toric lenses is recorded separately, with the greatest minus or least plus power first and the least minus or greatest plus power second, separated by a slash

    Center Thickness (CT)

    • Measured using a dedicated thickness gauge or the gauge on the radioscope
    • Read only the larger outer dial, marked in increments of 0.01mm
    • Record CT to the nearest 0.01mm
    • Minus power lenses typically have CTs between 0.10 and 0.20mm, while plus power lenses typically have CTs between 0.20 and 0.40mm

    Overall Diameter (OAD) and Optic Zone Diameter (OZD)

    • OAD measured using a lens loupe or V-gauge
    • Record OAD to the nearest 0.1mm
    • OZD determined by measuring the distance between the peripheral curve systems

    Peripheral Curve System (PCS) and Peripheral Curve System Width (PCSW)

    • PCS width specified in mm (secondary, intermediate, and peripheral)
    • Total width of PCS corresponds to only half the lens, so multiply by 2 to describe the total width
    • Verified with a lens loupe

    Peripheral Curve System Blend

    • Verified with a lens loupe
    • Classified as Light (L), Medium (M), or Heavy (H) based on the ease of seeing the junctions between the curves

    Color

    • Standard colors include blue, brown, green, and gray
    • Options to help patients identify the right or left lens:
      • A black dot can be inked on the periphery of the right lens
      • Use a gReen or gRay lens for the right eye, and a bLue lens for the left eye

    Review of GP Lens Designs

    • Determine the type of toric GP lens by calculating the difference between radioscope readings (converted to diopters) and lensometry readings (already in diopters), and then dividing the smaller number into the larger one to obtain a ratio
    • Ratios are always the larger number divided by the smaller number
    • Use the table to identify the lens design based on the ratio

    GP Lens Care System Components

    • Cleaner: Removes lipids, mucin, protein, and cosmetics from CL surfaces. Daily cleaning is essential to prevent deposit accumulation.
    • Conditioner: Has four functions:
      • Cushioning: Provides comfort between the CL and cornea.
      • Wetting: Makes CL surfaces more hydrophilic for better tear film spread.
      • Disinfection: Safeguards against contamination.
      • Lubrication: Relieves drying and breaks up deposits.
    • Hydration: Daily protein remover and periodic enzymatic cleaner for removing protein deposits.
    • Lubricant: Relieves drying, rewets, breaks up deposits, and rinses away debris.
    • Saline: For rinsing and filling scleral GP and hybrid CLs. Must be preservative-free saline.

    GP CL Care Systems

    • Chemical Systems: Advantages: good anti-microbial activity, easy to use. Disadvantages: preservatives may cause sensitivity or allergy.
      • One Bottle Multipurpose: Examples include B&L Boston Simplus, Tangible Clean, and Menicon Unique pH.
      • Two Bottle/Multiple Step: Examples include B&L Boston Original, B&L Boston Advance, and Lobob Optimum.
    • Oxidative (Hydrogen Peroxide) Systems: Advantages: excellent anti-microbial activity, ideal for patients with preservative sensitivities. Disadvantages: complicated to use, requires neutralization.
      • Examples: AMO Oxycept UltraCare and Alcon Clear Care Plus.
    • Protein Removal: Examples include B&L Boston One Step Liquid Enzymatic Cleaner and Menicon Progent.
    • Lubricants: Examples include AMO Blink Contacts, B&L Boston Rewetting Drops, and Menicon Rewetting Drops.
    • Non-Preserved Saline: Examples include Medical Addipack Unit Dose, Menicon's Lacripure, and B&L Specialty Vision ScleralFil.

    Preparation, Insertion, Re-centering, and Removal of Corneal GP Lenses

    • Preparation: Work over a clean surface, wash and rinse hands, and inspect the CL for damage.
    • Insertion: Stare straight ahead, retract the lower lid, and place the CL on the cornea. Release the inferior lid before the superior lid.
    • Re-centering: Determine the CL location, look in the opposite direction, and gently manipulate the CL to the center of the cornea using the lids.
    • Removal: Two methods: Lid Margin Technique and Canthus (Blink) Technique.

    Evaluating Corneal GP CLs on the Eye

    • BCR Selection: Initial choice depends on corneal curvature, including cylinder.
    • Characteristics of Fitting Philosophies: Lid Attachment, Modified Lid Attachment, and Interpalpebral Fitting.
    • Centration: CL should remain centered over the visual axis between blinks. Decentration is acceptable if the OZD covers the pupil and the edge doesn't put excessive pressure on the limbus.
    • Movement: CL should have sufficient vertical movement for tear exchange, typically 1mm to 1.5mm.
    • Assessment: Evaluate the fitting philosophy, centration, movement, and fluorescein patterns.

    Impact of Design Changes and Troubleshooting for Non-Specialty Corneal GP CLs

    • BCR: Modify in 0.10mm increments, steepen to tighten the fit, and flatten to loosen the fit.
    • OAD: Modify in 0.5mm increments, increase to steepen the fit, and decrease to loosen the fit.### FINAL LENS Parameters
    • FINAL LENS Parameters: -0.75DS / 7.65 BCR / 9.7 OAD

    OZD (Ocular Zone Diameter)

    • Increase or decrease in concert with OAD
    • Flatten BCR by 0.05mm while increasing OZD by 0.5mm to maintain the same fitting relationship
    • Dependent on pupil size, Refractive error, Corneal curvature, and Lid tension

    PCR (Peripheral Curve Radius)

    • Modify in 1.0 mm increments for testing purposes
    • Ensures adequate tear pump for delivery of O2
    • Aids in debris removal, eliminates bearing, and widens or flattens the peripheral curve radii to increase clearance and loosen the fit

    Clinical Setting Example

    • Flattening the peripheral curve radius: Increase the radius value to allow for more tear exchange
    • Example: SCR 8.80 / PCR 10.80 → SCR 9.80 / PCR 11.80 (by increasing PCR by 1.0mm)

    PCW (Peripheral Curve Width)

    • Modify in 0.20 mm increments
    • Flattening: Widen/increase width in mm
    • Steepening: Reduce width in mm

    Blend

    • Default: "Medium" blend if not specified
    • Functions: Remove debris, loosen fit, eliminate bearing, and enhance patient comfort

    Edge

    • Critical to patient comfort
    • Modification based on power: (+) Lenticular (High minus >5.00D), (-) Lenticular (Low minus)

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    Description

    Learn about the steps involved in preparing, inserting, and removing contact lenses properly. This quiz covers important hygiene practices and techniques to ensure safe and healthy use of contact lenses.

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