Central visual fields for short wavelength sensitive pathways in glaucoma and ocular hypertension

Area of Science:

• Ophthalmology
• Visual Neuroscience
• Optometry

Background:

• Conventional visual acuity and kinetic visual fields are often normal in early glaucoma and ocular hypertension.
• Short-wavelength sensitive (SWS) visual pathways show selective vulnerability in these conditions.
• Color vision deficits, particularly with blue stimuli, may indicate early glaucomatous changes.

Purpose of the Study:

• To investigate central visual field sensitivity in primary open-angle glaucoma (POAG) and ocular hypertension (OHT) using blue and yellow test flashes.
• To quantify deficits in SWS cone pathways and medium/long-wavelength sensitive (MWS/LWS) cone pathways in POAG and OHT patients.
• To compare visual field sensitivity across different eccentricities in the central visual field.

Main Methods:

• Studied central visual fields of 33 POAG patients, 32 OHT patients, and 24 age-matched normal controls.
• Utilized blue and yellow test flashes on bright yellow backgrounds to assess SWS and MWS/LWS cone pathway sensitivities.
• Measured sensitivities at the fovea and at 2.5, 5, 10, and 15 degrees eccentricities in specific retinal meridians.

Main Results:

• All groups showed normal sensitivity to yellow flashes (MWS/LWS cones).
• POAG and OHT groups exhibited significant sensitivity deficits to blue flashes (SWS cones) across the central visual field (6X and 1.8X, respectively, compared to normals).
• Localized glaucomatous field defects were observed in some OHT subjects with blue flashes, but not yellow flashes.

Conclusions:

• SWS visual pathways are selectively vulnerable in POAG and OHT, manifesting as reduced blue color vision sensitivity.
• Blue-yellow perimetry can detect early visual field deficits not apparent with conventional testing.
• These findings highlight the importance of assessing color vision in glaucoma and ocular hypertension management.