How is contrast sensitivity affected in glaucoma and how does it differ from acuity testing?

How is contrast sensitivity affected in glaucoma and how does it differ from acuity testing?

• A. Acuity remains relatively preserved early while contrast sensitivity is reduced, especially at higher spatial frequencies.
• B. Contrast sensitivity remains normal in glaucoma.
• C. Both contrast sensitivity and acuity decline at the same rate.
• D. Glaucoma does not affect contrast sensitivity.

Answer: (A)

Focus on how glaucoma affects visual function beyond just sharp central vision. Glaucoma damages retinal ganglion cells and their pathways, which reduces the ability to detect low-contrast patterns, especially when the patterns are fine (high spatial frequency). This means contrast sensitivity becomes impaired early, even when the eye can still resolve small, high-contrast details. Acuity testing, like Snellen charts, uses high-contrast targets and primarily gauges the smallest detail you can resolve at high contrast. Because central, high-contrast vision can be relatively preserved until later stages of glaucoma, acuity often remains near normal early on. So the key idea is that contrast sensitivity declines first, particularly for fine details, while acuity stays relatively preserved in the early disease.

Focus on how glaucoma affects visual function beyond just sharp central vision. Glaucoma damages retinal ganglion cells and their pathways, which reduces the ability to detect low-contrast patterns, especially when the patterns are fine (high spatial frequency). This means contrast sensitivity becomes impaired early, even when the eye can still resolve small, high-contrast details. Acuity testing, like Snellen charts, uses high-contrast targets and primarily gauges the smallest detail you can resolve at high contrast. Because central, high-contrast vision can be relatively preserved until later stages of glaucoma, acuity often remains near normal early on. So the key idea is that contrast sensitivity declines first, particularly for fine details, while acuity stays relatively preserved in the early disease.