Wiedman and Tabin graded high-altitude retinopathy (HAR) based on fundoscopic changes. The degree of HAR correlates with high-altitude cerebral edema (HACE). The authors are from the Massachusetts Eye and Ear Infirmary and the University of Vermont.
Signs of HAR:
(1) increasingly dilated retinal veins and arteries
(2) diffuse or punctate preretinal hemorrhages
(3) vitreous hemorrhages
(4) papillary hemorrhages
(5) peripapillary hyperemia
(6) papilledema
Parameters used for grading:
(1) dilation of retinal veins, with the venule-to-arteriole ratio (VAR)
(2) retinal hemorrhages
(3) vitreous hemorrhages
(4) papilledema
|
Retinal Vein Dilatation |
Retinal Hemorrhages |
Vitreous Hemorrhages |
Papilledema |
Grade |
|
none |
absent |
absent |
absent |
0 |
|
mild; VAR 3:2 |
<= 1 disc area |
absent |
absent |
I |
|
moderate; VAR 3.5:2 |
<= 2 disc areas |
absent |
absent |
II |
|
marked; VAR 4:2 |
<= 3 disc areas; may be paramacular |
may be present, < 3 disc areas (minor) |
absent |
III |
|
engorged with bluish-purple color; VAR 4.5: 2 |
> 3 disc areas; may be macular with visual loss |
present; >= 3 disc areas (major) |
present; > 2 diopters |
IV |
where:
• The diameter of the normal artery is about 80% if the vein (VAR 5:4; DeGowin's Diagnostic Examination).
• Retinal hemorrhages may be intraretinal or preretinal. If intraretinal the blood vessels can be seen clearly. If preretinal the blood vessels will be obscured.
• Paramacular hemorrhages are adjacent to the macular area. Macular hemorrhages are within the macula.
• Vitreous hemorrhages may be diffuse or dense.
• It may be necessary to adjust the grade for vitreous hemorrhage. Any vitreous hemorrhage makes the grade at least Grade III.
Specialty: Emergency Medicine, Critical Care, Pulmonology, Neurology
