Abstract
Purpose: :
In some patients with thyroid-associated ophthalmopathy (TAO), ocular hypertension (OH) is a major problem. Thus we performed this study to determine the relationship between OH and TAO.
Methods: :
The mean age of the subjects was 43 yr, ranging from 15 to 84 yr. MRI, non-contact tonometry, exophthalmometry with Hertel's exophthalmometer, examination to determine the presence of upper lid swelling, and measurement of the height of the palpebral fissure were performed on 4902 right eyes of patients with TAO. The areas of the four rectus muscles were measured in a coronal section of the orbital MRI. Multivariable analysis was also applied to the test the influence of various independent variables such as exophthalmos, the total area of the four rectus muscles, age, presence of upper lid swelling, height of palpebral fissure, and gender.
Results: :
The patients had a mean exophthalmos of 16.1 mm, and 5.7% of the subjects were classified as having OH. The IOPs were correlated with proptosis (P<0.0001, R=0.163; IOP=12.1+ 0.197 x degree of exophthalmos); the total area of the extraocular muscles (P<0.0001,R=0.175; IOP=13.6+1.35 x total area of the four retcus muscles); and the presence of upper lid swelling (P<0.0001). There was a high correlation between proptosis and age (P<0.0001, R= -0.316). However, there were no relationships between IOPs and age (P = 0.0953, R= -0.024), gender (P = 0.988), or palpebral-fissure height (P = 0.330). Multivariable analysis showed that the total area of the four rectus muscles is the parameter most correlated with the occurrence of OH in TAO (P<0.0001).
Conclusions: :
Multivariable analysis showed that the total area of the four rectus muscles is the factor most correlated with the occurrence of OH in patients with TAO (P<0.0001), but there is also some correlation with proptosis. If the patients with TAO had no signs of proptosis but still show OH, it is necessary to check their extraocular muscles.
Keywords: orbit • intraocular pressure • clinical (human) or epidemiologic studies: outcomes/complications