[Idiopathic orbital inflammatory syndrome: Report of 24 cases]

Delayed Surgical Reversal of Optic Nerve Compression Leads to Exponential Degeneration of Optic Nerve Fibers and Selective Sparing of the Small Fibers

Purpose

To evaluate the effectiveness of surgical reversal of experimental optic nerve compression in treating persistent compressive optic neuropathy and to explore the relationship between surgical outcomes and the timing of the procedure.

Methods

Surgical reversal procedures (decompression surgery) were conducted at five time intervals: 1, 3, and 7 days and 2 and 3 weeks following optic nerve compression in a rabbit model. The groups were labeled as DC-1d, DC-3d, DC-7d, DC-2w, and DC-3w, respectively. The study investigated changes in ganglion cell complex (GCC) thickness using spectral-domain optical coherence tomography and the percentage of surviving retinal ganglion cells (RGCs) through immunofluorescence staining and optic nerve axons stained with p-phenylenediamine at 4 weeks after decompression. Additionally, the area distribution of surviving axons was analyzed.

Results

The decline in GCC thickness was halted following decompression. The remaining thickness of the GCC in group DC-1d was found to be statistically significantly higher at 2, 3, and 4 weeks postonset compared to the no-decompression group. Similarly, GCC thickness in group DC-3d was significantly higher at 3 and 4 weeks postonset. The percentage of surviving RGCs and axons at 4 weeks postonset exhibited an exponential correlation with the onset time of decompression, with R2 values of 0.72 and 0.78, respectively. The surviving axon area declined following delayed decompression.

Conclusions

Persistent substantial compression on the optic nerve leads to exponential degeneration of the optic nerve, initially affecting larger optic nerve fibers. Early intervention aimed at relieving the compression on the optic nerve may offer potential benefits in mitigating the degenerative effects and conserving visual function.

Orbital inflammatory pseudotumor: new advances in diagnosis, pathogenesis, and treatment

Orbital inflammatory pseudotumor (OIP) is a benign, non-specific inflammatory disorder that commonly occurs in middle-aged adults and is usually unilateral but can occur bilaterally. Its clinical manifestations have tremendous clinical heterogeneity and vary according to the site of infiltration and the degree of lesions, including orbital pain, swelling, diplopia, proptosis, restricted eye movement, and decreased visual acuity. Clinical features, Image characteristics and pathological examinations often need to be evaluated to confirm the diagnosis. Currently, there is no systematic research on the pathogenesis of OIP, which may be related to immunity or infection. The first-line treatment is glucocorticoids. Radiotherapy, immunosuppressants, and biologics can be considered for treatment-resistant, hormone-dependent, or intolerant patients. In this review, we aim to summarize and focus on new insights into OIP, including new diagnostic criteria, pathogenesis, and discoveries in new drugs and treatment strategies. In particular, we highlight the literature and find that T cell-mediated immune responses are closely related to the pathogenesis of OIP. Further exploration of the mechanism and signaling pathway of T cells in the immune process will help to identify their therapeutic targets and carry out targeted therapy to treat refractory OIP and reduce the side effects of traditional treatments.

Clinical Characteristics of Idiopathic Orbital Inflammation Syndrome in Relation to Intraocular Pressure

Purpose

To investigate the clinical characteristics of idiopathic orbital inflammation and changes in intraocular pressure (IOP) before and after its treatment.

Patients and Methods

We retrospectively studied 20 eyes from the medical records of 19 patients who were diagnosed with idiopathic orbital inflammation between April 1, 2004, and April 30, 2019, at Toyama University Hospital. The inflammation site (type of disease), treatment provided, IOP before and after treatment, and the symptoms (proptosis, decreased ocular movements or diplopia, periorbital edema, and ocular pain) were analyzed.

Results

The types of idiopathic orbital inflammation were dacryoadenitis in 14, myositis in 7, diffuse-type in 3, and posterior periscleritis in 1 case. The mean IOP after treatment was 15.4±3.9 mm Hg, which was significantly lower than the mean pretreatment IOP of 19.0±5.3 mm Hg (p = 0.009). Before treatment, all cases with the diffuse-type had high IOPs of 21 mm Hg or more. Ocular pain and eye movement disorders were present in 86% and 100% of subjects in the group with an IOP of 21 mm Hg or higher, but 38% and 31% in the group with an IOP of 20 mm Hg or lower, respectively.

Conclusion

Diffuse-type of idiopathic orbital inflammation is prone to develop high IOP. Patients with idiopathic orbital inflammation and high IOP exhibit many symptoms such as decreased ocular movements, diplopia, and ocular pain.

Correlation Between IVIM-DWI Parameters and Pathological Classification of Idiopathic Orbital Inflammatory Pseudotumors: A Preliminary Study

Objective

To investigate the correlation between intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and the pathological classification of idiopathic orbital inflammatory pseudotumors (IOIPs).

Methods

Nineteen patients who were diagnosed with IOIPs (a total of 24 affected eyes) between November 2018 and December 2020 were included in the study. All the patients underwent magnetic resonance imaging orbital plain scans and IVIM-DWI multiparameter scans before an operation. The true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) values were obtained. Based on histopathology, the lesions were divided into three types: lymphocytic infiltration, fibrosclerotic, and mixed. The correlation between IVIM-DWI parameters and pathological classification was tested with the histopathological results as the gold standard. The data were analyzed using SPSS version 17.0, with P < 0.05 defined as significant.

Results

Among the 19 patients (24 eyes) affected by IOIP, there were no significant differences between IOIP pathological classification and gender or age (P > 0.05). There were statistically significant differences between the D and f values for different pathological types of IOIP and IVIM parameters (P < 0.05), and there was no significant difference in D* value between the different pathological types (P > 0.05).

Conclusion

The D and f values showed correlation with different types of IOIP, and the sensitivity of the D value was higher than that of the f value. The D* value showed no significant distinction between pathological types of IOIP.