Diffuse-type idiopathic orbital inflammation is particularly prone to increase an individual’s intraocular pressure (IOP), according to research published in Clinical Ophthalmology. Patients with idiopathic orbital inflammation and elevated IOPs also have decreased ocular movements, diplopia, and ocular pain, the report shows.

The retrospective study took into account 20 eyes of 19 participants (mean age 55.4±13.7 years, 18 women, 1 man) who were diagnosed with idiopathic orbital inflammation between April 1, 2004, and April 30, 2019. Researchers reviewed the participants’ inflammation sites, treatments, IOPs prior to and following treatment, and symptoms of decreased ocular movements/diplopia, periorbital edema, and eye pain.

Of the 20 eyes observed, the study notes 14 cases of dacryoadenitis inflammation, 7 cases of myositis inflammation, 3 cases of diffuse inflammation, and 1 case of periscleritis inflammation. Patients with diffuse-type idiopathic orbital inflammation had the highest IOPs before treatment at 25±4.2 mm Hg, significantly higher than the dacryoadenitis-type (P =.01).


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The mean IOP following treatment was significantly lower than before treatment (15.4±3.9 mm Hg vs 19.0±5.3 mm Hg, respectively, P =.009). 

All participants with diffuse idiopathic orbital inflammation had IOPs higher than 20 mm Hg. In patients with IOPs of 21 mm Hg or higher before treatment, 86% reported ocular pain and 100% reported eye movement disorders. In patients with IOPs lower than 21 mm Hg, 38% reported ocular pain and 31% reported eye movement disorders.

“There have been few reports on changes in IOP before and after [idiopathic orbital inflammation] treatment,” the researchers explain. 

The elevated IOP seen in idiopathic orbital inflammation is likely caused by an increase in episcleral venous pressure, the study suggests. In particular, they explain that patients with diffuse inflammation may be at increased risk of developing increased venous pressure. However, “even if IOP is high due to idiopathic orbital inflammation, it can be reduced with existing steroid treatment in many cases,” according to the publication.

The limitations of this study include the use of noncontact tonometer rather than Goldmann applanation tonometer to measure IOP (which may result in lower measurements), the documentation of periorbital pain (which was based solely on patient reports), and the small sample size. 

Reference

Otsuka M, Yunoki T, Ozaki H, Hayashi A. Clinical characteristics of idiopathic orbital inflammation syndrome in relation to intraocular pressure. Clin Ophthalmol. 2022;16:1467-1473. doi:10.2147/opth.s361645