CONTACT LENS – I
UNIT 4
Topic 1: Ordering Rigid Contact Lenses – Writing a Prescription to the Laboratory
Introduction
After completing contact lens fitting and finalizing lens parameters, the optometrist must order the final lens from the manufacturing laboratory. Accurate communication between the practitioner and laboratory is essential for successful contact lens fabrication.
The contact lens prescription contains all the required lens specifications needed for manufacturing the lens accurately. Any error in prescription writing may lead to poor fitting, discomfort, visual problems, or corneal complications.
Therefore, the optometrist must understand the correct method of writing a rigid contact lens prescription and the significance of each parameter included in the order.
Definition of Contact Lens Prescription
A contact lens prescription is a written order containing all necessary lens parameters and patient details required by the laboratory for manufacturing the contact lens.
Objectives of Ordering Contact Lenses
- To communicate accurate lens specifications to the laboratory
- To obtain the correct lens design and material
- To ensure proper fitting and visual correction
- To avoid manufacturing errors
- To maintain patient comfort and corneal health
Importance of Accurate Prescription Writing
Rigid contact lenses are custom-made lenses. Small changes in lens parameters can significantly affect:
- Lens fitting
- Visual acuity
- Lens movement
- Comfort
- Corneal physiology
Hence, accurate prescription writing is extremely important.
INFORMATION REQUIRED BEFORE ORDERING RGP LENSES
Before writing the final prescription, the following information should be collected:
- Patient history
- Refraction
- Keratometry readings
- Trial lens findings
- Over-refraction
- Lens fitting assessment
- Fluorescein evaluation
COMPONENTS OF RGP CONTACT LENS PRESCRIPTION
1. Patient Information
Basic patient details should always be included.
Details Included
- Patient name
- Age
- Gender
- Date of examination
- Identification number (if applicable)
Importance
- Proper patient identification
- Avoids confusion in laboratory
- Useful for future reference
2. Eye Specification
Separate specifications should be written for:
- Right Eye (OD)
- Left Eye (OS)
Importance
Each eye may require different lens parameters.
3. Lens Power
Definition
Lens power is the refractive correction incorporated into the contact lens.
It is expressed in diopters (D).
Determination of Lens Power
Lens power is determined from:
- Subjective refraction
- Vertex compensation
- Over-refraction
Importance
- Provides accurate refractive correction
- Improves visual acuity
- Reduces residual refractive error
4. Base Curve (BC)
Definition
Base curve is the curvature of the posterior central surface of the contact lens.
It is expressed in millimeters (mm).
Selection of Base Curve
Base curve is selected according to:
- Keratometry readings
- Fluorescein pattern
- Lens movement
- Corneal shape
Example
BC = 7.80 mm
Importance
- Determines fitting relationship
- Affects centration
- Controls tear exchange
- Influences comfort
5. Total Diameter (TD or DIA)
Definition
Total diameter is the total width of the contact lens measured from edge to edge.
Selection of Diameter
Diameter depends upon:
- Corneal diameter
- Palpebral aperture
- Lens design
- Corneal curvature
Example
DIA = 9.4 mm
Importance
- Affects centration
- Influences movement
- Controls lens stability
- Improves comfort
6. Optic Zone Diameter (OZD)
Definition
Optic zone diameter is the central optical portion of the lens responsible for refractive correction.
Example
OZD = 7.8 mm
Importance
- Provides clear vision
- Must cover pupil area
- Reduces glare and halos
7. Peripheral Curves
Definition
Peripheral curves are flatter curves surrounding the optic zone.
Importance
- Improve tear exchange
- Reduce edge pressure
- Improve comfort
- Assist lens movement
Types of Peripheral Curves
- Single peripheral curve
- Multiple peripheral curves
- Aspheric peripheral curves
8. Edge Design
Definition
Edge design refers to the contour and thickness of the lens edge.
Importance
- Affects comfort
- Influences lid interaction
- Controls tear exchange
Common Edge Designs
- Rounded edge
- Knife edge
- Chisel edge
9. Lens Material
Definition
Lens material refers to the polymer from which the RGP lens is manufactured.
Common RGP Materials
- Silicone acrylate
- Fluoro-silicone acrylate
Importance of Material Selection
- Determines oxygen permeability
- Affects wettability
- Influences comfort
- Controls durability
10. Center Thickness (CT)
Definition
Center thickness is the thickness of the lens at its central portion.
Importance
- Affects oxygen transmission
- Influences rigidity
- Improves handling
11. Tint (If Required)
Definition
Tint is a coloring added to the lens to improve handling or cosmetic appearance.
Types of Tint
- Visibility tint
- Cosmetic tint
- Handling tint
12. Special Instructions
Additional instructions may be written for special lens modifications or clinical requirements.
Examples
- Prism ballast
- Fenestration
- Lenticulation
- Special edge design
- Aspheric design
FORMAT OF RGP CONTACT LENS PRESCRIPTION
| Parameter | Example |
|---|---|
| Patient Name | ABC |
| Eye | OD / OS |
| Lens Power | -3.00 D |
| Base Curve | 7.80 mm |
| Diameter | 9.4 mm |
| Optic Zone Diameter | 7.8 mm |
| Material | Fluoro-silicone acrylate |
| Center Thickness | 0.14 mm |
| Tint | Blue visibility tint |
WRITING PRESCRIPTION FOR SPECIAL CASES
1. Keratoconus
Special instructions may include:
- Steeper base curve
- Smaller diameter
- Aspheric design
- High Dk material
2. Aphakia
High plus power lenses require:
- Appropriate lenticulation
- Increased center thickness
3. High Astigmatism
Special toric or bitoric designs may be prescribed.
COMMON ERRORS IN PRESCRIPTION WRITING
- Incorrect base curve
- Wrong power notation
- Missing diameter
- Incomplete material details
- Improper eye labeling
Consequences of Incorrect Prescription
- Poor lens fitting
- Blurred vision
- Discomfort
- Corneal complications
- Lens intolerance
COMMUNICATION WITH THE LABORATORY
Importance
Good communication between the practitioner and laboratory is essential for successful lens fabrication.
Information to be Communicated
- Lens parameters
- Special modifications
- Material requirements
- Urgency of delivery
- Special fitting considerations
Modern Methods of Ordering
- Written order forms
- Computerized ordering systems
- Online ordering portals
- Email prescriptions
Verification Before Sending Order
Before sending the prescription to the laboratory, the practitioner should verify:
- Correct patient details
- Accurate lens parameters
- Right eye labeling
- Special instructions
- Lens material selection
Importance of Accurate Ordering in RGP Lenses
- Improves fitting success
- Provides better visual acuity
- Reduces remakes
- Improves patient comfort
- Maintains corneal health
Topic 2: Checking and Verifying Contact Lenses from Laboratory
Introduction
After a contact lens is manufactured by the laboratory, it must be carefully checked and verified before dispensing it to the patient. Verification ensures that the lens parameters ordered by the practitioner are accurately manufactured.
Even minor manufacturing errors may affect:
- Lens fitting
- Visual acuity
- Patient comfort
- Corneal health
Therefore, every contact lens received from the laboratory should undergo systematic inspection and verification before use.
Definition of Contact Lens Verification
Contact lens verification is the process of evaluating and confirming that the manufactured contact lens matches the prescribed specifications and is free from defects.
Objectives of Contact Lens Verification
- To confirm accuracy of lens parameters
- To detect manufacturing defects
- To ensure patient safety
- To improve fitting success
- To prevent complications
Importance of Checking Contact Lenses
Verification is important because:
- Laboratory errors may occur
- Incorrect parameters affect fitting
- Defective lenses may damage the cornea
- Improper lenses reduce visual quality
STEPS IN CONTACT LENS VERIFICATION
1. Inspection of Packaging
Introduction
The packaging should be examined carefully before opening the lens container.
Things to Check
- Patient name
- Right and left eye labeling
- Lens parameters
- Expiry date
- Condition of package
Importance
- Prevents dispensing wrong lens
- Ensures proper identification
- Detects packaging damage
2. Verification of Lens Parameters
The practitioner should compare the ordered prescription with the laboratory specifications.
Parameters to Verify
- Lens power
- Base curve
- Diameter
- Optic zone diameter
- Center thickness
- Material
- Tint
3. Checking Lens Power
Definition
Lens power verification confirms that the lens contains the prescribed refractive correction.
Instrument Used
Lens power is checked using:
- Radiuscope
- Lensometer
- Vertometer
Procedure
- Lens is positioned properly on the instrument
- Power is measured carefully
- Measured value is compared with prescribed power
Importance
- Ensures accurate visual correction
- Detects manufacturing error
- Improves visual acuity
4. Checking Base Curve
Definition
Base curve verification confirms the curvature of the posterior central lens surface.
Instrument Used
Base curve is checked using:
- Radiuscope
- Keratometer (special techniques)
Importance
- Determines fitting relationship
- Affects lens movement
- Influences comfort
- Maintains tear exchange
Effects of Incorrect Base Curve
| Incorrect Parameter | Result |
|---|---|
| Too Steep | Tight fit and poor tear exchange |
| Too Flat | Excessive movement and instability |
5. Checking Diameter
Definition
Diameter verification confirms the total width of the lens.
Instrument Used
- Magnifying gauge
- Profile projector
- Contact lens measuring magnifier
Importance
- Affects lens centration
- Controls lens stability
- Influences comfort
6. Checking Center Thickness
Definition
Center thickness is the thickness of the lens at the central portion.
Instrument Used
Thickness is measured using:
- Thickness gauge
- Dial thickness gauge
Importance
- Affects oxygen transmissibility
- Influences rigidity
- Affects handling
7. Checking Optic Zone Diameter
Definition
Optic zone diameter verification confirms the size of the optical portion of the lens.
Importance
- Ensures proper visual quality
- Reduces glare and halos
- Improves night vision
8. Verification of Lens Material
Importance
The prescribed material should be confirmed because different materials possess different:
- Oxygen permeability
- Wettability
- Rigidity
- Durability
Common RGP Materials
- Silicone acrylate
- Fluoro-silicone acrylate
9. Surface Inspection
Introduction
The lens surface should be examined carefully for defects and irregularities.
Methods of Surface Inspection
- Magnification
- Slit lamp examination
- Shadowgraph inspection
Defects to be Checked
- Scratches
- Surface pits
- Cracks
- Deposits
- Surface warpage
- Bubbles
Importance
- Improves comfort
- Prevents corneal injury
- Maintains visual quality
10. Edge Inspection
Introduction
Lens edges should be smooth and properly finished.
Importance of Edge Inspection
- Improves comfort
- Prevents lid irritation
- Ensures proper tear exchange
Defective Edges May Cause
- Foreign body sensation
- Corneal staining
- Excessive tearing
- Lens intolerance
11. Wetting Characteristics
Definition
Wetting refers to the ability of tears to spread evenly over the lens surface.
Importance
- Improves comfort
- Provides stable vision
- Reduces deposits
Poor Wettability Causes
- Blurred vision
- Dry spots
- Discomfort
- Surface deposits
12. Lens Warpage Detection
Definition
Lens warpage refers to distortion or deformation of the contact lens shape.
Causes of Warpage
- Improper manufacturing
- Heat exposure
- Improper storage
- Mechanical stress
Effects of Warpage
- Blurred vision
- Poor fitting
- Discomfort
- Variable fluorescein pattern
13. Slit Lamp Examination of Lens
Importance
Slit lamp examination provides detailed evaluation of:
- Surface quality
- Edge quality
- Deposits
- Scratches
- Lens defects
14. Verification on Patient’s Eye
Introduction
After laboratory verification, the lens should be evaluated on the patient’s eye.
Parameters Evaluated on Eye
- Lens centration
- Lens movement
- Comfort
- Visual acuity
- Fluorescein pattern
Ideal RGP Lens Movement
The ideal RGP lens movement is approximately:
0Importance of Fluorescein Evaluation
- Determines lens fit
- Assesses tear distribution
- Detects apical bearing
- Evaluates edge clearance
COMMON MANUFACTURING DEFECTS
| Defect | Effect |
|---|---|
| Scratches | Discomfort and corneal irritation |
| Warped lens | Blurred vision and poor fitting |
| Incorrect power | Poor visual acuity |
| Incorrect base curve | Improper fit |
| Poor edge finish | Lid irritation |
| Poor wettability | Dryness and unstable vision |
Importance of Proper Verification
- Improves fitting success
- Maintains corneal health
- Improves patient comfort
- Reduces complications
- Ensures accurate vision correction
Consequences of Dispensing Incorrect Lens
- Corneal edema
- Corneal abrasion
- Discomfort
- Blurred vision
- Lens intolerance
- Hypoxia
Topic 3: Modifications Possible with Rigid Contact Lenses
Introduction
Rigid Gas Permeable (RGP) contact lenses can be modified in several ways to improve lens fitting, comfort, visual performance, tear exchange, and corneal physiology.
Every patient has a different corneal shape, tear film quality, eyelid anatomy, and refractive requirement. Therefore, standard lens designs may not always provide an ideal fit.
Lens modifications are special changes made in lens parameters or design to solve fitting problems and improve clinical performance.
Definition of Lens Modification
Lens modification refers to alteration of contact lens parameters or design to improve fitting relationship, comfort, vision, or corneal health.
Objectives of Lens Modification
- To improve lens centration
- To increase patient comfort
- To improve tear exchange
- To reduce corneal complications
- To improve visual acuity
- To correct fitting problems
TYPES OF MODIFICATIONS POSSIBLE WITH RGP LENSES
The common modifications include:
- Base curve modification
- Diameter modification
- Peripheral curve modification
- Edge modification
- Optic zone modification
- Center thickness modification
- Lenticulation
- Fenestration
- Toric modifications
- Aspheric modifications
- Prism ballast
1. BASE CURVE MODIFICATION
Definition
Base curve modification involves changing the curvature of the posterior central lens surface.
Purpose
- To improve fitting relationship
- To control lens movement
- To improve centration
- To enhance tear exchange
A. Steepening the Base Curve
Effects
- Decreases lens movement
- Improves centration
- Increases sagittal depth
Indications
- Flat fitting lens
- Excessive lens movement
- Poor centration
Disadvantages
- Reduced tear exchange
- Risk of hypoxia
- Tight lens syndrome
B. Flattening the Base Curve
Effects
- Increases lens movement
- Improves tear exchange
- Reduces sagittal depth
Indications
- Steep fitting lens
- Lens adherence
- Poor tear exchange
Disadvantages
- Lens decentration
- Excessive movement
- Corneal staining
2. DIAMETER MODIFICATION
Definition
Diameter modification involves changing the total lens diameter.
Importance of Diameter
- Affects lens centration
- Controls lens movement
- Influences comfort
- Determines corneal coverage
A. Increasing Diameter
Effects
- Improves centration
- Decreases movement
- Increases lens stability
Indications
- Lens decentration
- Excessive movement
- Small palpebral aperture
B. Decreasing Diameter
Effects
- Increases movement
- Improves tear exchange
- Reduces lens awareness
Indications
- Tight lens fit
- Poor tear exchange
- Large corneal vaulting
3. PERIPHERAL CURVE MODIFICATION
Definition
Peripheral curve modification involves altering the flatter curves surrounding the optic zone.
Functions of Peripheral Curves
- Improve tear exchange
- Reduce edge pressure
- Improve comfort
- Assist lens movement
A. Flattening Peripheral Curves
Effects
- Increases edge clearance
- Improves tear exchange
- Increases movement
Indications
- Tight fitting lens
- Peripheral corneal staining
- Poor tear exchange
B. Steepening Peripheral Curves
Effects
- Reduces edge clearance
- Improves lens stability
- Reduces movement
Indications
- Excessive edge lift
- Lens discomfort
- Excessive movement
4. EDGE MODIFICATION
Definition
Edge modification involves changing the shape and contour of the lens edge.
Importance of Edge Design
- Affects comfort
- Influences lid interaction
- Controls tear exchange
Types of Edge Modifications
- Rounded edge
- Knife edge
- Chisel edge
- Thin edge
- Thick edge
A. Rounded Edge
Advantages
- Improves comfort
- Reduces lid irritation
B. Knife Edge
Advantages
- Reduces lens thickness
- Improves tear exchange
Disadvantages
- May produce discomfort
- Can damage corneal epithelium
5. OPTIC ZONE MODIFICATION
Definition
Optic zone modification involves changing the size of the optical portion of the lens.
A. Increasing Optic Zone Diameter
Advantages
- Improves visual quality
- Reduces glare and halos
- Improves night vision
Disadvantages
- Reduces peripheral clearance
- May decrease tear exchange
B. Decreasing Optic Zone Diameter
Advantages
- Improves tear exchange
- Increases peripheral clearance
Disadvantages
- Glare and halos
- Poor night vision
6. CENTER THICKNESS MODIFICATION
Definition
Center thickness modification involves altering the thickness of the central lens portion.
A. Increasing Center Thickness
Advantages
- Improves rigidity
- Reduces lens flexure
- Easier handling
Disadvantages
- Reduced oxygen transmission
- Increased lens weight
B. Reducing Center Thickness
Advantages
- Improves oxygen transmission
- Improves comfort
- Reduces lens weight
Disadvantages
- Lens flexure
- Fragility
7. LENTICULATION
Definition
Lenticulation is a modification in which the peripheral lens thickness is reduced while maintaining the central optic zone.
Purpose of Lenticulation
- Reduce lens weight
- Improve comfort
- Improve centration
- Reduce edge thickness
Types of Lenticulation
- Plus lenticulation
- Minus lenticulation
A. Plus Lenticulation
Used mainly in high plus lenses to reduce edge thickness.
B. Minus Lenticulation
Used mainly in high minus lenses to reduce central thickness and weight.
8. FENESTRATION
Definition
Fenestration refers to the creation of a small hole in the contact lens.
Functions of Fenestration
- Improves tear exchange
- Improves oxygen supply
- Reduces suction effect
- Reduces lens adherence
Indications
- Scleral lenses
- Tight fitting lenses
- Corneal edema
Disadvantages
- Bubble formation
- Visual disturbance
- Deposit accumulation
9. TORIC MODIFICATIONS
Definition
Toric modifications involve incorporation of toricity into the lens design.
Types of Toric Modifications
- Front surface toric
- Back surface toric
- Bitoric design
Indications
- Corneal astigmatism
- Residual astigmatism
- Toric corneas
10. ASPHERIC MODIFICATIONS
Definition
Aspheric modification involves gradual flattening of lens curvature from center to periphery.
Advantages
- Improves centration
- Reduces spherical aberration
- Improves fitting on irregular corneas
Indications
- Keratoconus
- Irregular cornea
- Aspheric corneal shapes
11. PRISM BALLAST
Definition
Prism ballast is a modification in which prism is incorporated into the lens to improve lens stability and orientation.
Functions
- Improves lens stability
- Maintains proper lens orientation
- Prevents rotation
Indications
- Toric lenses
- Special lens designs
MODIFICATIONS FOR SPECIFIC CLINICAL CONDITIONS
1. Keratoconus
Common modifications:
- Steeper base curve
- Aspheric design
- Small diameter lens
- High Dk material
2. High Astigmatism
Common modifications:
- Toric design
- Bitoric lens
- Increased stability modifications
3. Tight Lens Syndrome
Common modifications:
- Flatten base curve
- Increase edge lift
- Reduce diameter
4. Excessive Lens Movement
Common modifications:
- Steepen base curve
- Increase diameter
- Reduce edge lift
ADVANTAGES OF LENS MODIFICATIONS
- Improves fitting success
- Enhances comfort
- Improves visual quality
- Maintains corneal health
- Reduces complications
DISADVANTAGES OF EXCESSIVE MODIFICATION
- Complex fitting
- Higher cost
- Manufacturing difficulty
- Lens instability
- Reduced oxygen transmission
Importance of Proper Lens Modification
Lens modifications should be based on:
- Clinical findings
- Fluorescein evaluation
- Lens movement
- Corneal health
- Patient symptoms
Improper modifications may worsen fitting problems and increase complications.
Topic 4: Common Handling Instructions
Subtopics
- Insertion Technique
- Removal Technique
- Do’s and Don’ts of Contact Lens Wear
Introduction
Proper handling of contact lenses is essential for successful contact lens wear. Incorrect handling techniques may lead to:
- Lens damage
- Corneal injury
- Infection
- Discomfort
- Lens contamination
Every contact lens wearer must be instructed carefully regarding insertion, removal, cleaning, and general care of contact lenses.
Rigid Gas Permeable (RGP) lenses require special handling because they are smaller, rigid, and more mobile than soft contact lenses.
Objectives of Handling Instructions
- To teach safe insertion and removal
- To prevent contamination
- To maintain lens quality
- To improve patient comfort
- To reduce complications
INSERTION OF RGP CONTACT LENSES
Definition
Insertion is the process of placing the contact lens correctly onto the cornea.
Preparation Before Lens Insertion
Before inserting contact lenses, the patient should:
- Wash hands thoroughly
- Use mild soap without lotion
- Dry hands with lint-free towel
- Inspect lens for defects
- Ensure lens is clean
Importance of Hand Washing
- Prevents infection
- Reduces contamination
- Maintains lens cleanliness
METHODS OF INSERTION
1. One-Handed Technique
Procedure
- Place the lens on the tip of the index finger
- Use the middle finger of the same hand to pull down the lower eyelid
- Use the opposite hand to lift the upper eyelid
- Ask the patient to look straight ahead
- Gently place the lens on the cornea
- Release eyelids slowly
Advantages
- Simple technique
- Easy for beginners
- Good control during insertion
2. Two-Handed Technique
Procedure
- Lens is held on the index finger
- Both eyelids are controlled using opposite hands
- Lens is placed directly on the cornea
Advantages
- Better eyelid control
- Useful for anxious patients
Precautions During Insertion
- Avoid touching lens with fingernails
- Do not force the lens
- Prevent lens dropping
- Keep eyes relaxed
Common Problems During Insertion
| Problem | Cause |
|---|---|
| Excessive blinking | Anxiety or fear |
| Lens dropping | Poor hand control |
| Lens discomfort | Dirty or inverted lens |
| Watering | Initial lens awareness |
REMOVAL OF RGP CONTACT LENSES
Definition
Removal is the process of safely taking the contact lens off the eye without damaging the cornea or lens.
Preparation Before Removal
- Wash hands properly
- Dry hands completely
- Ensure good lighting
- Look into mirror
METHODS OF RGP LENS REMOVAL
1. Blink Method
Procedure
- Open eyes widely
- Place finger at outer canthus
- Stretch eyelids laterally
- Blink firmly
- Lens pops out onto hand or towel
Advantages
- Simple method
- No direct lens touching
- Commonly used for RGP lenses
Disadvantages
- Lens may fall
- Difficult for beginners
2. Finger and Thumb Method
Procedure
- Pull eyelids apart gently
- Apply slight pressure at lens edge
- Lift lens carefully from cornea
Advantages
- Good control
- Reduced chance of lens loss
3. Suction Holder Method
Definition
A small suction cup device is used to remove the lens.
Procedure
- Moisten suction holder
- Touch it gently to lens surface
- Remove lens carefully
Indications
- Patients with poor dexterity
- Large RGP or scleral lenses
Precautions
- Do not apply excessive suction
- Avoid corneal touch
Precautions During Removal
- Never use fingernails
- Do not squeeze lens excessively
- Remove lens gently
- Use towel beneath face to avoid dropping
Common Problems During Removal
| Problem | Cause |
|---|---|
| Lens adherence | Tight fit or dryness |
| Lens dropping | Poor handling |
| Corneal irritation | Improper technique |
| Difficulty removing lens | Anxiety or poor dexterity |
DO’S OF CONTACT LENS WEAR
1. Wash Hands Before Handling
Always wash hands before touching contact lenses.
2. Clean Lenses Regularly
Lenses should be cleaned daily using recommended solutions.
3. Store Lenses Properly
Store lenses in clean disinfecting solution inside a clean lens case.
4. Follow Wearing Schedule
Patients should follow the practitioner’s instructions regarding wearing time.
5. Attend Follow-Up Visits
Regular follow-up examinations help detect complications early.
6. Replace Lens Case Regularly
Lens cases should be replaced periodically to prevent contamination.
7. Use Recommended Solutions Only
Only approved contact lens solutions should be used.
8. Inspect Lens Before Use
Always check the lens for:
- Cracks
- Deposits
- Scratches
- Warpage
9. Remove Lens During Redness or Pain
If discomfort or redness occurs, the lens should be removed immediately.
10. Keep Backup Spectacles
Patients should always keep spectacles available for emergency use.
DON’TS OF CONTACT LENS WEAR
1. Do Not Sleep with Lenses Unless Advised
Sleeping with lenses increases risk of:
- Hypoxia
- Infection
- Corneal edema
2. Do Not Use Tap Water
Tap water may contain microorganisms harmful to the eye.
3. Do Not Share Contact Lenses
Sharing lenses may transmit infection.
4. Do Not Rub Eyes Excessively
Excessive rubbing may:
- Displace lens
- Damage cornea
- Scratch lens
5. Do Not Use Expired Solutions
Expired solutions may lose disinfecting ability.
6. Do Not Wear Damaged Lenses
Cracked or chipped lenses may injure the cornea.
7. Do Not Exceed Wearing Time
Excessive wearing time may cause:
- Hypoxia
- Corneal edema
- Discomfort
8. Do Not Use Saliva to Wet Lens
Saliva contains bacteria and may cause infection.
9. Do Not Ignore Symptoms
Symptoms such as:
- Pain
- Redness
- Blurred vision
- Photophobia
should be reported immediately.
10. Do Not Wear Lenses During Eye Infection
Lens wear should be discontinued during active ocular infection.
PATIENT EDUCATION
Importance
Patient education is essential for:
- Successful lens wear
- Prevention of complications
- Improved compliance
- Long-term ocular health
Instructions Given to Patients
- Proper hygiene
- Correct insertion and removal
- Lens cleaning procedure
- Wearing schedule
- Warning signs of complications
COMPLICATIONS DUE TO IMPROPER HANDLING
| Improper Practice | Complication |
|---|---|
| Poor hygiene | Infection |
| Sleeping with lens | Corneal edema |
| Using damaged lens | Corneal abrasion |
| Improper cleaning | Deposit formation |
| Excessive wear | Hypoxia |
Importance of Proper Lens Handling
- Maintains corneal health
- Improves comfort
- Increases lens life
- Prevents complications
- Improves patient satisfaction
