Anterior Scleritis, Scleral Thinning, and Intraocular Pressure Measurement

Necrotizing Scleritis: A Review

Necrotizing scleritis is the most destructive and vision-threatening form of scleritis. Necrotizing scleritis can occur in systemic autoimmune disorders and systemic vasculitis, as well as following microbial infection. Rheumatoid arthritis and granulomatosis with polyangiitis remain the commonest identifiable systemic diseases associated with necrotising scleritis. Pseudomonas species is the most common organism causing infectious necrotizing scleritis, with surgery the most common risk factor. Necrotizing scleritis has the highest rates of complications and is more prone to secondary glaucoma and cataract than other phenotypes of scleritis. The differentiation between non-infectious and infectious necrotizing scleritis is not always easy but is critical in the management of necrotizing scleritis. Non-infectious necrotizing scleritis requires aggressive treatment with combination immunosuppressive therapy. Infectious scleritis is often recalcitrant and difficult to control, requiring long-term antimicrobial therapy and surgical debridement with drainage and patch grafting due to deep-seated infection and the avascularity of the sclera.

Correlation between corneal and scleral pneumatonometry: an alternative method for intraocular pressure measurement

PURPOSE

To evaluate scleral pneumatonometry as an alternative method for measuring intraocular pressure (IOP).

DESIGN

Prospective cross-sectional study.

METHODS

Adult subjects with healthy eyes were recruited from the Comprehensive Eye Service at the University of Illinois Eye and Ear Infirmary from August 2008 through February 2009. Study measurements included corneal pneumatonometry (IOPk), scleral pneumatonometry (IOPs), axial length (AL), spherical equivalent (SE), and central corneal thickness (CCT). Main outcome measures were scleral IOP and corneal IOP.

RESULTS

Analysis included a monocular data set from single eyes of 97 subjects (age: 18-82 years). IOPs was consistently higher than IOPk, and correlated positively with IOPk (r = 0.57, P < .0001), age (r = 0.51, P < .0001), and SE (r = 0.32, P = .0002). The difference between scleral and corneal IOP (IOPs - IOPk) correlated positively with IOPs (r = 0.89, P < .0001), age (r = 0.57, P < .0001), and SE (r = 0.34, P < 0.0001). Bland-Altman analysis for agreement between scleral and corneal pneumatonometry measurements showed a mean difference of 8.08 mm Hg, with the 95% limit of agreement between -3.47 and 19.64 mm Hg. Regression analysis yielded the following equation: IOPk = 11.9 + 0.32(IOPs) - 0.05(Age).

CONCLUSIONS

Scleral pneumatonometry correlates positively with corneal pneumatonometry and is more accurate at lower values and in younger patients. When adjusted for age, scleral pneumatonometry may be an adequate alternative in situations where corneal measurements are impractical.

Scleritis: Immunopathogenesis and molecular basis for therapy

Scleritis is a heterogeneous group of diseases characterized by inflammation of the sclera, which may be due to local or systemic infections or immune mediated diseases. Numerous studies over the last decade have lead to significant progress in understanding the pathogenesis and treatment of this severe and potentially blinding disease. Immunological investigations of non-infectious scleritis and associated diseases have indicated that scleritis is an autoimmune disease and studies on the nature of the local inflammatory response have revealed the prominent role of T and B cells and cytokines, such as TNF-alpha, which in turn has resulted in clinical trials showing the effectiveness of local steroid treatment, anti-TNF and anti-B cell therapy. The widespread use of imaging has led to the realization that posterior scleritis is more common than previously recognized and testing for ANCA antibodies has revealed the prominent role of immune mechanisms in a subset of patients with scleritis and associated systemic vasculitis.