PURPOSE: To report two cases of Pseudomonas aeruginosa corneal ulcers as a complication of overnight orthokeratology lens wear.
METHODS: Case report.
RESULTS: Two 11-year-old girls with acute central corneal ulcers were referred to our hospital. In both cases, the ulcers were about 2 mm in diameter, located centrally, contained dense cellular infiltration, and discharged purulent material. Intensive topical ceftazidime was applied to treat the ulcers. Cultures of the scraped corneal tissues and the contact lens storage solutions in both cases grew P. aeruginosa, which was sensitive to the antibiotic. The presenting best-corrected visual acuity was hand motion at 20 cm in one patient and 6/20 in the other. Both patients had received several months of overnight orthokeratology treatment with rigid gas permeable contact lenses to correct myopia (-4.25 D and -4.75 D in the two affected eyes). The final best-corrected visual acuity was 6/60 in one patient and 6/7.5 in the other.
CONCLUSIONS: Overnight orthokeratology contact lens wear carries a potential risk of corneal ulcer and may cause significant visual impairment in children.
Available online 23 November 2018
Ophthalmic Technology Assessment
Use of Orthokeratology for the Prevention of Myopic Progression in Children: A Report by the American Academy of Ophthalmology
Nice piece by Edric Wei, OD:
Generally speaking, an orthok lenses should be replaced annually to prevent any serious ocular complication.
What will happen to the orthok lenses over years?
As the lenses aged, protein deposits may build up and lens surface scratches may develop, both of which may affect the integrity of the lens and affects lens wearing experience.
As we know, proteins are complex organic compounds that exist throughout our body. In our tear, the main protein component is known as lysozyme which functions to combat microbial activities on the surface of the eye. As you keep wearing your lenses, lysozyme will denature (a chemical and physical transformation that causes a change in the configuration of the protein) due to oxidation and drying. The denatured lysozyme can build up on the surface of contact lenses forming protein deposits. Thus, reduced its’ transparency and integrity and may also challenge the body’s immune system causing inflammation, irritation, redness and itching.
Some of the serious ocular reactions known related to protein deposits are giant papillary conjunctivitis (GPC) and superior limbic keratoconjunctivitis (SPK), while keratitis is another immune response that experts have linked to denatured protein deposits.
Giant Pupillary Conjunctivitis (GPC)
Superior Limbic Keratoconjunctivitis (SPK)
Besides that, lens surface scratches may also develop while you are washing your lenses and during storage. Those scratches may increase the chances of protein deposit to stick on the lens surface.
Scratches seen on rigid gas permeable lenses.
Personally, I do advise my patient to replace the lenses annually and even stated the condition in the consent form. However, if the patient is really taking good care of their lenses I will somehow allow them to stick with it for up to 2 years provided they attend all the necessary follow-ups, no excessive protein deposits and lenses surface scratches are seen.
Edric Wei, OD