iPad In Hand, Vision In Sight: Glaucoma Screening in West Africa
Author: Owais M. Aftab, BS (1)
Rutgers New Jersey Medical School
Glaucoma is a slowly progressive neurodegenerative disorder of the optic nerve and the leading cause of irreversible blindness worldwide. A study published by Prince et al. in Ophthalmology is focused on evaluating the performance of the Melbourne Rapid Fields (MRF) tablet-based visual field testing method in a high-risk population of Black Africans in Tema, Ghana. The researchers aimed to evaluate the utilization of the affordable and easy-to-use clinic-based MRF tool in low-resource settings.
The study cohort included 37 healthy control participants and 66 participants with glaucoma that attended a clinical appointment at the Tema Eye Center in Ghana. The participants underwent visual field testing using both the MRF application on an iPad and current gold standard evaluation of visual fields the Humphrey Field Analyzer (HFA).
The results of the study showed that the MRF-based mean deviation (MD) and pattern standard deviation (PSD) were significantly different from those generated by the HFA. Notably, the MRF consistently generated a lower value for MD as compared to the HFA, and it generally generated a higher value for PSD as compared with the HFA. Further, the MRF differed significantly from the HFA in its ability to grade glaucomatous visual field defects, as its sensitivity was significantly lower (p=0.03), though its specificity was not significantly different (p=0.76). Further, on AUCROC analysis, the MRF did not significantly differ from the HFA in its ability to correctly identify glaucoma in general (p=0.27), mild glaucoma (p=0.32), and moderate/severe glaucoma (p=0.25).
Furthermore, agreement biases were significant for both MD (p=0.03) and PSD (p=0.03), suggesting a weak agreement between the 2 devices. However, there was no significant difference between the two methods in terms of false-positive rate (FPR) and false-negative rate (FNR). The study also evaluated patient perceptions of their experience with the MRF and found that over 90% of users agreed that iPad-based visual field testing was simple to use, easy to remember how to use, and would use it at home if instructed.
Overall, while the MRF does not appear ready for utilization as a replacement to the HFA, it may hold potential as an alternative to the HFA in settings where HFA testing/monitoring is unfeasible. While there were differences in the test metrics like MD, PSD, and sensitivity, other metrics were not significantly different, like specificity and AUCROC comparing MRF vs. HFA for glaucoma in general, mild, and moderate/severe glaucoma detection. Alternative research and evaluation of MRF in low-resource settings, high-risk populations, and for home-use are warranted despite its deviations from the HFA when considering its portability, affordability, and user-friendly nature.
Original article: https://www.ophthalmologyglaucoma.org/article/S2589-4196(21)00206-4/pdf
