Two types of manifestations may occur in GO: (1) functional abnormalities due to hyperactivity of the sympathetic nervous system, produced by the thyrotoxicosis, and (2) infiltrative lesions involving the contents of the orbit. Only the infiltrative type has a serious prognosis. Two classifications of eye signs are being used to date. The first one is depicted. in Table 12-2.
Table 2. Classification of the Ocular Changes in Graves' Disease
|
Classes |
Grades |
Ocular Symptoms and Signs |
|---|---|---|
|
(1) Note that in addition to classification by type of involvement, there is also a grading according to severity. |
||
|
0-6 |
0,a,b, |
No signs or symptoms. |
|
1 |
c |
Only (signs limited. to upper lid retraction and stare, with or without lid lag and proptosis). |
|
2 |
Soft tissue involvement (symptoms of excessive lacrimation, sandy sensation, retrobulbar discomfort, and photophobia, but not diplopia); objective signs as follows: |
|
|
0 |
Absent |
|
|
a |
Minimal (edema of conjunctivae and lids, conjunctival injection, and fullness of lids, often with orbital fat extrusion, palpable lacrimal glands, or swollen extraocular muscle palpable beneath lower lids) |
|
|
b |
Moderate (above plus chemosis, lagopthalmos, lid fullness) |
|
|
c |
Marked |
|
|
3 |
Proptosis associated. with classes 2 to 6 only (specify if inequality of 3 mm or more between eyes, or if progression of 3 mm or more under observation). |
|
|
0 |
Absent (20 mm or less) |
|
|
a |
Minimal (21-23 mm) |
|
|
b |
Moderate (24-27 mm) |
|
|
c |
Marked (28 mm or more) |
|
|
4 |
Extraocular muscle involvement (usually with diplopia) |
|
|
0 |
Absent |
|
|
a |
Minimal (limitation of motion, evident at extremes of gaze in one or more directions) |
|
|
b |
Moderate (evident restriction of motion without fixation of position) |
|
|
c |
Marked (fixation of position of a globe or globes) |
|
|
5 |
Corneal involvement (primarily due to lagopthalmos) |
|
|
0 |
Absent |
|
|
a |
Minimal (stippling or cornea) |
|
|
b |
Moderate (ulceration) |
|
|
c |
Marked (clouding, necrosis, perforation) |
|
|
6 |
Sight loss (due to optic nerve involvement) |
|
|
0 |
Absent |
|
|
a |
Minimal (disc pallor or choking, or visual field defect; vision 20/20 to 20/60) |
|
|
b |
Moderate (disc pallor or choking, visual field defect, 20/70 to 20/200) |
|
|
c |
Marked (blindness, i.e. failure to perceive light; vision less than 20/200) |
|
Criticism has been raised with regard to this NOSPECS mnemonic (composed of the first character describing each grade. See the table ). The criticism basically states that although NOSPECS is "an ingenious catchy memory aid for medical students who have forgotten how to examine a Graves' eye" it is insufficient in that it is directed. towards the mean status of the eye so that it is impossible, using this index, to evaluate isolated. components separately. In other words, although the NOSPECS index does not reflect it, important and essential components of the eye complex may have improved or deteriorated.. For this reason it was proposed that data should be provided separately and not put together in an overall index. 19Others on the basis of the same criticism proposed a modification of NOSPECS. 20In order to be able to assess treatment of active inflammatory ophthalmopathy and also to predict therapeutic outcome and to select patients for surgical or non-surgical treatment, they introduced the clinical activity score (CAS). 21(Table 12-3)
Table 3. Proposed Classification System to Assess Disease Activity in Thyroid Eye Disease
|
One point is given for each sign present. The sum of these points defines the activity score. (From Mourits et al., (21) with permission) |
|---|
|
Pain |
|
Painful, oppressive feeling on or behind the globe |
|
Pain on attempted. up, side, or down gaze |
|
Redness |
|
Redness of the eyelids |
|
Diffuse redness of the conjunctiva |
|
Swelling |
|
Chemosis |
|
Edema of the eyelid(s) |
|
Increase proptosis of 2 mm or more during a period between 1 and 3 months |
|
Impaired function |
|
Decrease in visual acuity of 1 or more lines on the Snellen chart (using a pinhole) during a period between 1 and 3 months |
|
Decrease of eye movements in any direction equal to or more than 5 degrees during a period of time between 1 and 3 months |
This scoring system was shown to have a high predictive value for therapeutic outcome of immunosuppressive treatment of infiltrative ophthalmopathy. 22