A creeping hazard: Presumed limbal stem cell deficiency from occupational chemical exposure

While limbal stem cell deficiency (LSCD) is more commonly reported secondary to Stevens–Johnson syndrome or chronic contact lens wear, chronic occupational exposure to chemical irritants remains a rare and underreported etiology. Case Report A 50-year-old male mechanic working in a chemical factory presented with decreased vision in the right eye for 5 years, accompanied by persistent irritation and foreign body sensation. He gives history of continuous exposure to chemical fumes, welding light, and industrial chemical agents (as well as multiple episodes of accidental exposure to petroleum-related products) since the last 7 years. Examination of the right eye revealed diffuse conjunctival hyperemia and a fibrovascular pannus extending from 10 to 6 o’clock position [Fig. 1] with extension into the paracentral and peripheral cornea [Fig. 2]. A fluorescein positive nonresolving epithelial defect with hypertrophic changes was noted at 11 o’ clock position over the paracentral cornea. Lens showed early anterior capsular cataract with nuclear sclerosis grade 1 and posterior subcapsular changes [Figs. 3 and 4]. The left eye also showed an early fibrovascular pannus superiorly over 2 clock hours. Corneal impression cytology showed the presence of goblet cells and minimal subepithelial fibrosis. Diagnosis suggestive of secondary partial LSCD was considered with options of simple limbal epithelial stem cell transplantation (SLET) followed by clear corneal phacoemulsification; however, due to financial constraints, medical management was initiated and the patient was followed regularly for 3 months with no progression of pannus. Clinical photographs, obtained with informed consent over multiple visits spanning 2 years, support a creeping onset of LSCD from prolonged chemical fumes and petrochemical exposure rather than an acute insult.Figure 1: (Right eye) Slit view of the cornea showing conjunctivalization with pannus formation from 10’ to 6’o clock positionFigure 2: (Right eye) Parallelepiped section showing involvement of epithelium superiorly and inferiorlyFigure 3: (Right eye) Slit view showing conjunctivalization with a nonresolving epithelial defect with overlying hypertrophic changes. Lens shows central dense cataractFigure 4: (Right eye) Slit view of the cornea from the medial side showing conjunctivalisation over the entire nasal halfDiscussion Unlike acute chemical injuries, petrochemical exposure leads to progressive limbal niche damage, conjunctivalization, and impaired stem cell turnover, resulting in delayed LSCD.[1,2] In this case, progressive pannus formation with cytological evidence of goblet cells, subepithelial fibrosis, and loss of corneal epithelial markers highlights the insidious nature of chronic chemical exposure.[3,4] Primary preventive measures include strict safety protocols, proper usage and disposal of industrial products, proper handling of factory equipment, and ensuring correct adherence to the use of personal safety gear/equipment.[5] Author contributions Dr. Sharon Mary George - Concept, design, literature search, clinical studies, data acquisition, data analysis, manuscript preparation and editing. Dr. Naveena M: definition of intellectual Content, design, manuscript preparation and manuscript review and supervision. Declaration of patient consent The author certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in this journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.