Assessment of Visual Function Using Yellow-Tinted Filter in Patients with Pre-Perimetric and Early Open Angle Glaucoma.

Purpose: This study aimed to assess the effect of an external yellow-tinted filter (KIROS 1-400 lens) on visual function in patients with pre-perimetric glaucoma (PPG) and early primary open-angle glaucoma (POAG). The primary outcomes were contrast sensitivity (CS) and visual field (VF) indices assessed using standard automated perimetry (SAP).

Methods: This comparative observational, within-subject study included 30 patients with PPG (30 eyes) and 50 with POAG (50 eyes) recruited from the Ophthalmology Department of the 401 General Military Hospital, Athens, between January and December 2022. CS was measured using the Pelli-Robson chart. VF indices, including mean deviation (MD), pattern standard deviation (PSD), visual field index (VFI), and Glaucoma Hemifield Test (GHT) classifications, were assessed with SAP with the 24-2 SITA-standard strategy on the Humphrey Field Analyzer II 740. All testing was performed both with and without the yellow filter KIROS 1-400 (Essilor International) in the same eyes.

Results: The KIROS 1-400 filter significantly enhanced CS in both PPG and POAG eyes, increasing the median logCS by 0.03. However, while statistically significant, this improvement may not be clinically meaningful. In contrast, no significant changes were observed in the VF indices (MD, PSD, and VFI) when the filter was applied. Analysis of GHT results revealed that the filter reduced borderline classifications and showed high precision (0.733) and recall (0.846) for "outside normal limits" classifications. However, the agreement between the filtered and unfiltered GHT results was fair.

Conclusion: The KIROS 1-400 filter significantly enhanced CS in patients with PPG and POAG without notable effects on the VF indices. However, caution is advised when interpreting GHT results obtained with yellow-tinted filters. Further studies are recommended to evaluate the filter's long-term clinical benefits and its potential role in glaucoma management.