Corneal epithelial alterations resulting from use of chlorine-disinfected contact tonometer after myopic photorefractive keratectomy.
OBJECTIVE
This study aimed to describe a previously unreported complication associated with the use of chlorine-disinfected applanation tonometer heads for intraocular pressure measurement after excimer laser photorefractive keratectomy.


METHODS
Two retrospective case reports.


METHODS
Two patients underwent, respectively, a 7-diopter and a 4-diopter myopic excimer laser correction in their first eye 2 weeks apart. Complete epithelial closure of the ablated area was observed by biomicroscopy in the first-week examination.


METHODS
Four weeks after photorefractive keratectomy, a complete ophthalmic examination was performed. Goldmann applanation tonometry was performed bilaterally after thoroughly rinsing and drying the tonometer biprism, which had been immersed regularly in a chlorine 5000-parts per million solution.


METHODS
Slit-lamp examination and corneal topographic surface regularity were measured.


RESULTS
A few minutes after applanation tonometry, both patients reported ocular discomfort in the excimer laser-treated eyes, whereas the untreated fellow eyes were painless. Punctate corneal lesions and superficial epithelial cell clumping were present in the first patient's treated eye, predominantly in the inferior aspect of the applanated cornea. Visual inspection showed a normal tonometer tip. In the second patient's treated cornea, a focal epithelial defect was identified biomicroscopically, which corresponded to the steeper region within the ablation zone on the videokeratograph. In this case, crystal deposits were found on the tonometer tip. The epithelial alterations resolved without sequelae in both cases.


CONCLUSIONS
Disinfecting solutions of chlorine can cause crystal deposit formation on the tonometer head. Applanation tonometry after repeated disinfection with chlorine solutions appears to have the potential for disrupting the epithelial layer of the healing cornea. Covered contact tonometry or noncontact tonometry should be evaluated as alternative methods to chemically disinfected contact tonometry for intraocular pressure measurement after excimer laser surgery, especially during the first postoperative month.
Department of Ophthalmology, Albacete General Hospital, Valencia, Spain.
M J
MJ
Maldonado
D000328:Adult; D002713:Chlorine / Q000009:adverse effects*; D003316:Corneal Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D019781:Corneal Topography; D003460:Crystallization; D004202:Disinfectants / Q000009:adverse effects*; D004203:Disinfection / Q000379:methods; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000601:surgery*; D009883:Ophthalmic Solutions; D018903:Photorefractive Keratectomy; D012189:Retrospective Studies; D014065:Tonometry, Ocular / Q000295:instrumentation*
D004202:Disinfectants; D009883:Ophthalmic Solutions; D002713:Chlorine