A 58-year-old woman complains of metamorphopsia. Biomicroscopy shows a yellowish foveal spot with an absent foveal reflex but no break in the inner retinal surface. According to the Gass classification, what stage of idiopathic macular hole does this represent?

• A Stage 2, small full-thickness hole less than 400 microns
• B Stage 1b, occult macular hole with eccentric foveolar dehiscence
• C Stage 1a, impending macular hole with foveal detachment ✓
• D Stage 4, full-thickness hole with complete posterior vitreous separation

Explanation

Gass stage 1a shows a yellow foveal spot or ring with loss of the foveal depression, reflecting foveal detachment from anteroposterior vitreous traction, while stage 1b shows the yellow ring of occult hole formation. No full-thickness retinal defect exists yet, so options A and D are excluded. Stage 2 requires a definite eccentric full-thickness break smaller than 400 microns. Many stage 1 holes resolve spontaneously if the vitreofoveal traction releases.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.