Geographic Information System Mapping Reveals Pediatric Glaucoma Risk Factors

Geographic information system (GIS) mapping software can be used to assess associations between disease and geospatial location and help clinicians visualize demographic risk factors for pediatric glaucoma, according to research published in Ophthalmology Glaucoma.  

“Our study performs original GIS mapping of visual outcomes superimposed together with social risk factors on the same distribution map, with statistical analysis showing significant association,” according to the study authors. “This enables the practicing ophthalmologist to be able to consider patients’ social factors, especially factors such as travel distance, when assessing prognosis and potential outcomes.” However, the investigators acknowledge that this novel method does not replace the need for statistical analysis. 

Researchers from the University of California (UC) Davis Eye Center included 177 patients with pediatric glaucoma (eyes, 233) who were seen at the UC Davis Medical Center between 2001 and 2019 in the retrospective cohort study. The team mapped participants to a 3-digit zip code and evaluated risk factors associated with poor visual outcomes. Primary and secondary outcome measures were final visual acuity and intraocular pressure (IOP) at final follow-up visit, respectively. Poor vision was defined as visual acuity worse than 20/200.  

A total of 27.9% of eyes (n=65) had poor vision at follow-up, according to the report. Age and IOP demonstrated negative associations with visual acuity. Every 1 mm increase in IOP decreased the odds ratio (OR) of having good visual acuity by 4% (P =.03) and every 1 year increase in age decreased the OR of good visual acuity by 6% (P =.04). 

Overall, patients with a private insurance carrier had a 3.5 mm Hg lower final IOP compared with individuals with Medicaid coverage (P =.004). The GIS mapping data suggested that living further from the clinic may be associated with poorer visual outcomes, according to the report, but there were no statistical associations (P =.369).

“Although childhood glaucoma presenting at birth generally has a poor long-term prognosis, our finding likely represents the adverse effect of delayed diagnosis and referral of children to a tertiary center,” the study authors explain. “In our study, the risk factor of insurance type was used as a proxy variable reflecting a patient’s socioeconomic status, as insurance status is an appropriate surrogate marker for income, socioeconomic status, and other social determinants of health.” 

Study limitations include a retrospective nature, single center design, and failure to consider other glaucoma treatment centers in the zip code analysis.