Authors (including presenting author) :
Lai ACH (1)(2), Tsang CS (1), Chan KM (1)(2), Yuen KL (1)(2), Wong OM (1)(2)
Affiliation :
(1)Hong Kong Eye Hospital, (2)Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong
Introduction :
Humphrey visual field (HVF) 24-2 Swedish Interactive Thresholding Algorithm (SITA) Fast has been the gold standard for glaucoma diagnosis and monitoring. It is, however, limited by variable reliability due to patient performance, and occasional failure to detect early yet significant central visual field loss. With glaucoma being one of the top causes of irreversible blindness worldwide, higher testing efficiency and sensitivity in visual field test are essential in meeting the growing needs. HVF 24-2C SITA Faster (HVF24-2C) is a novel algorithm modified from the older HVF 24-2 SITA Fast (HVF24-2) algorithm to enhance the early detection and monitoring of central visual field defect. To our best knowledge, this is the first comparative study that compares the performance of HVF24-2C and HVF24-2 among glaucoma patients in clinical setting in Hong Kong.
Objectives :
To compare the reliability indices, summary values, testing time and the number of affected central points on pattern deviation plot of HVF24-2 and HVF24-2C.
Methodology :
Thirty patients diagnosed with various severity of glaucoma received visual field test with both HVF24-2 and HVF24-2C in the same visit. The false positive rate (FP), mean deviation (MD), pattern standard deviation (PSD) and visual field index (VFI) of the same patient were compared by paired t-test. The number of points with p< 0.05 or p< 0.01 within central 20-degree were counted and compared with paired t-test.
Result & Outcome :
The testing time is significantly shorter for HVF24-2C than HVF24-2 (249.03s vs 267.30s, p=0.029). The number of central points with p< 0.05 or p< 0.01 are significantly greater for HVF24-2C than HVF24-2 (for points with p< 0.05: 10.73 vs 7.07, p< 0.001; for points with p< 0.01: 8.87 vs 5.67, p< 0.001). There is no significant difference between the two algorithms in terms of FP, MD, PSD and VFI. Conclusion Compared with the older HVF24-2, HVF24-2C enables a significantly shorter testing time and detects a higher number of central visual field defects, potentially increasing the number of HVF performed by 7%. This could minimize patient fatigue, hence potentially more reliable results, achieve higher efficiency in service provision, and could be more sensitive in picking up clinically significant visual field defects.
