Ophthalmology Notes: Revised Gass & IVTS Classification- Macular Hole

There are two main classification schemes for macular holes.

Gass first described his clinical observations on the evolution of a macular hole:

Stage 1 MH, or impending MH, demonstrates a loss of the foveal depression.

A stage 1A is a foveolar detachment characterized a loss of the foveal contour and a lipofuscin-colored spot.

A stage 1B is a foveal detachment characterized by a lipofuscin-colored ring.

Stage 2 MH is defined by a full thickness break < 400µm in size. It might be eccentric with an inner layer “roof.” This can occur weeks to months following Stage 1 MHs. A further decline in visual acuity is also noted. In most cases, the posterior hyaloid has been confirmed to be still attached to the fovea on OCT analysis.

Stage 3 MH is further progression to a hole ≥400 µm in size. Nearly 100% of stage 2 MHs progress to Stage 3 and the vision further declines. A grayish macular rim often denotes a cuff of subretinal fluid. The posterior hyaloid is noted to be detached over the macula with or without an overlying operculum

Stage 4 MH is characterized by a stage 3 MH with a complete posterior vitreous detachment and Weiss ring.

Stage 0	Vitreomacular adhesion
Stage 1	Impending macular hole, vitreomacular traction syndrome Stage 1A – foveal pseudocyst, schisis in inner fovea Stage 1B – break in outer fovea
Stage 2	Early full-thickness macular hole Less than 400um diameter
Stage 3	Large full-thickness macular hole Greater than 400um diameter
Stage 4	Full-thickness macular hole with complete PVD

More recently, the The International Vitreomacular Traction Study (IVTS) Group also formed a classification scheme of vitreomacular traction and macular holes based on OCT findings[5]:

Vitreomacular adhesion (VMA): No distortion of the foveal contour; size of attachment area between hyaloid and retina defined as focal if </= 1500 microns and broad if >1500 microns

Vitreomacular traction (VMT): Distortion of foveal contour present or intraretinal structural changes in the absence of a full-thickness macular hole; size of attachment area between hyaloid and retina defined as focal if </= 1500 microns and broad if >1500 microns

Full-thickness macular hole (FTMH): Full-thickness defect from the internal limiting membrane to the retinal pigment epithelium. Described 3 factors:

1) Size -- horizontal diameter at narrowest point: small (≤ 250 μm), medium (250-400 μm), large (> 400 μm);

2) Cause -- primary or secondary;

3) Presence of absence of VMT