Dr S Werner proposed a formal classification system for orbital involvement in Graves' disease, which was approved by the American Thyroid Association (ATA), being published in 1969.
Acronym based on first letters of classes: NO SPECS
(1) Classes 0 and I (NO): "no threat"; Class I = formerly "mild" or "noninfiltrative"
(2) Classes II-VI (SPECS): "serious"; formerly "severe" or "infiltrative
Two forms presented:
(1) abridged
(2) detailed
Class |
Abridged Definition |
0 |
No signs or symptoms |
I |
Only signs, no symptoms |
II |
Soft tissue involvement (signs and symptoms) |
III |
Proptosis |
IV |
Extraocular muscle involvement |
V |
Corneal involvement (primarily due to lagophthalmos) |
VI |
Sight loss (due to optic nerve involvement) |
The higher the class with positive findings, the more extensive the involvement. Each class usually includes involvements indicated in the preceding classes.
Signs:
(1) upper lid retraction
(2) stare
(3) with or without lid lag
(4) with or without proptosis
Symptoms for Classes 0 to II:
(1) excessive lacrimation
(2) sandy sensation
(3) retrobulbar discomfort
(4) photophobia
(5) no diplopia
Class I |
Only Signs |
Grade |
absent |
proptosis <= 20 mm |
o |
minimal |
proptosis 21-23 mm |
a |
moderate |
24-27 mm |
b |
marked |
>= 28 mm |
c |
Class II |
Soft Tissue Involvement |
Grade |
absent |
|
o |
minimal |
edema of conjunctivae and lids, conjunctival injection, fullness of lids, often with orbital fat extrusion, palpable lacrimal glands, or swollen extraocular muscle palpable laterally beneath lower lids |
a |
moderate |
minimal findings, plus chemosis, lagophthalmos, lid fullness |
b |
marked |
|
c |
Class III |
Proptosis |
Grade |
absent |
20 mm or less |
o |
minimal |
21-23 mm |
a |
moderate |
24-27 mm |
b |
marked |
>= 28 mm |
c |
where:
• proptosis grades limited to Classes II to VI
• specify if inequality of 3 mm or more between eyes
• specify if progression of 3 mm or more under observation
Class IV |
Extraocular Muscle Involvement |
Grade |
absent |
|
o |
minimal |
limitation of motion, evident at extremes of gaze in one or more directions |
a |
moderate |
evident restriction of motion without fixation of position |
b |
marked |
fixation of position of a globe or globes |
c |
where:
• Class IV is usually associated with diplopia.
Class V |
Corneal Involvement |
Grade |
absent |
|
o |
minimal |
stippling of cornea |
a |
moderate |
ulceration |
b |
marked |
clouding, necrosis, perforation |
c |
Class VI |
Sight Loss |
Grade |
absent |
|
o |
minimal |
disc pallor or choking or visual field defect; vision 20/20 - 20/60 |
a |
moderate |
disc pallor or choking or visual field defect; vision 20/70 - 20/200 |
b |
marked |
blindness with failure to perceive light; vision < 20/200 |
c |
Activity descriptors are applied once the class of involvement is determined:
(1) active
(2) static
(3) inactive
Limitations:
• A variety of modifications to the schema have been proposed over the years to address perceived shortcomings in classification.
• One need was the distinction between patients with active, progressive disease from those with inactive, unchanging disease.
Specialty: Ophthalmology, Endocrinology
ICD-10: ,