Impression cytology links limbal stem cell deficiency and mustard gas keratopathy
Impression cytology showed varying degrees of limbal stem cell deficiency in patients with chronic or delayed-onset mustard gas keratopathy, a noninflammatory disease of the cornea in the eye, according to a study.
Iraqi forces used mustard gas extensively against Iranian troops during the Iran-Iraq war in the 1980s. More than 100,000 people were exposed to the agent, and an estimated 0.5% will develop complications that adversely affect visual acuity, the study authors said.
Additionally, many veterans of the 1991 Gulf War have long asserted that they were exposed to mustard-lewisite.
"Although there are some reports suggesting progressive [limbal stem cell deficiency] as a contributing factor to corneal manifestations associated with mustard gas, to the best of our knowledge, no study has described the actual pathogenesis of corneal manifestations in patients with mustard gas keratopathy," the authors said.
The prospective, observational case series included 35 eyes of 18 patients. Mean patient age at the time of sampling was 44.5 years; the mean interval between mustard gas exposure and sampling was 20 years.
The identification of goblet cells on the corneal side of ocular surface samples was considered evidence of corneal conjunctivalization and limbal stem cell deficiency. Clinical manifestation of limbal stem cell deficiency was graded as mild, moderate or severe in each quadrant of the cornea.
Study data showed the presence of goblet cells in at least one corneal quadrant in all 35 eyes. In addition, corneal clinical grading was significantly statistically more severe in the nasal and temporal quadrants than in the superior and inferior quadrants (P < .001), according to the study.