1. Hypoxic complications:
With soft contact lens there is only 1-2 % of tear exchange with each blink. It is 10-20% with RGP (Rigid Gas Permeable) or semisoft contact lens. This is known as adequate tear exchange.
If contact lens is steep fitted or the DK value is very low, or lens is very thick, oxygen supply to cornea is hampered and cornea starts becoming edematous with decreased sensations, superficial and deep vascularisation, micro cysts formation and
superficial punctuate keratitis.
Patient complains of redness in eyes, watering, blurring of vision and pain in eyes.
Most common causes of hypoxia encountered clinically are overwear, steep fitted lens or patient sleeps with contact lens in eyes. So, patient must be advised not to sleep with contact lens in eyes.
Treatment:
Remove the contact lens immediately and try to find out the cause
• Steep fitting, incomplete or inadequate blinking, patient slept with contact lens on, thick lens and poor quality material of
contact lens with low DK value
• Remove the cause and prescribe lubricating eye drops and topical antibiotics
• Call the patient after 3-4 days.
2. Infective complications:
Cornea may become infected with contaminated solution, lack of personal hygiene, use of tap water for contact lens storage or cleaning or from adjoining structures of eye.
Staphylococcus aureus, Acanthamoeba, Pseudomonas are the common microorganisms which infect cornea. Patient complains of redness, watering, blurring of vision, pain in eyes. On slit lamp examination conjunctival congestion with purulent discharge may be
seen.
Cornea may show some infected lesion. Lack of compliance to instructions and delayed reporting predispose the patient to develop vision threatening complications.
Treatment:
Ask the patient to discontinue use of contact lens till further instructions.
Take conjunctival swab and send for culture and sensitivity.
Take history of using tap water for contact lens cleaning.
Start antibiotics and lubricating eye drops and change the treatment if required as per culture report.
3. Allergic complications:
Patient may develop allergy to preservatives
of contact lens solution. Very rarely he becomes allergic to contact lens material. He starts complaining of itching, redness, watering .
He may develop Giant Papillary Conjunctivitis, follicular hypertrophy and hyperemia of conjunctiva.
Treatment:
Ask the patient to discontinue using contact lens for some time.
Prescribe topical antihistaminics and diluted steroids.
Once the symptoms are settled ask the patient to change the contact lens solution or the material as the case may be.
He can also change the wearing schedule or lens design.
He should be advised to use lubricating eye drops and clean his lenses regularly.
4. Giant Papillary Conjunctivitis:
It is papillary hyperplasia in the upper tarsal conjunctiva and occurs in 10-15 % cases of soft contact lens users and 1-3% users of semisoft contact lens.
Patient becomes aware of lens, complains of burning sensation, blurred vision,
intolerance to contact lens, mucinous discharge and drooping of upper eyelid.
Treatment:
Stop using contact lens for at least a few months. Use lubricating eye drops and diluted steroids, sodium chromoglycate
eye drops and vasoconstrictor eye drops.
5. Traumatic complications:
Patient may sustain injury with contact
lens edge or finger nail while inserting or removing the contact lens.
This may cause redness of eyes, watering and FB sensation of eyes.
Treatment:
Fluorescein staining should be done and area of injury should be drawn on prescription slip for future reference.
Stop using contact lens for some time.
Remove any eyelash or foreign body from eye if any.
Prescribe antibiotics and lubricating eye drops for 4-5 days.
6. Deposits:
They are most common with soft contact lens, more with extended wear than daily wear and least common with hard
contact lens.
Deposits consist of calcium and proteins from tears and cleaning solutions.
Deposits impair oxygen permeability, interfere with vision.
Lens surface becomes irregular and invites infection.
Treatment:
Patient should be advised to clean and disinfect contact lens regularly.
Deposit prone patients should be advised to use semisoft lenses instead of soft contact lens and daily wear contact lens instead of extended wear contact lens.
7. Dessication of cornea:
This is due to tear film disturbance caused
by contact lens.
Cornea may show 3-9 o’clock and 6 o’clock
staining or dimple staining.
Patient complains of redness, irritation,
photophobia and intolerance to contact lens.
3-9 o’clock staining is caused by thick lens and 6 o’clock staining is caused by incomplete blinking.
Dimple staining is due to tight fitting of contact lens.
Treatment:
Use a large lens of less thickness or a soft contact lens.
Stress the need of complete blinking.
Fitting of contact lens should be reassessed.
8. Toxic complications:
Certain drugs and preservatives of contact lens solution like Benzalkonium chloride, Thiomersal, etc.
get deposited on contact lens surface and manifest as toxicity of cornea and conjunctiva.
Patient complains of irritation, photophobia, watering, pain, etc.
Treatment:
Stop using contact lens for sometime. Change contact lens solution, clean and disinfect contact lens and use lubricating eye drops.
Tags:
Contact lens