Wallace et al used a scale to grade tortuosity and dilatation of retinal blood vessels in infants with retinopathy of prematurity. The authors are from Duke University, University of Utah and Children's Hospital of Philadelphia.
Parameters:
(1) tortuosity and/or diameter
(2) degree (within level)
Tortuosity and/or Diameter
Degree
Grade
less than normal
0
normal
almost less than normal
1
normal
2
normal
almost Pre-Plus
3
Pre-Plus
almost normal
4
Pre-Plus
5
Pre-Plus
almost Plus
6
Plus
almost Pre-Plus
7
Plus
8
Plus
severe
9
where:
• Less than normal indicates straighter or thinner.
• Grades 3 and 4 may be difficult to distinguish reliably.
• Grades 6 and 7 may be difficult to distinguish reliably
• To make the scale symmetrical there probably needs to be 2 additional grades for less than normal.
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