ABSTRACT
This study explores the complication of secondary intraocular pressure (IOP) elevation and consequent glaucoma development in Graves' orbitopathy (GO), an autoimmune disorder associated with hyperthyroidism. Utilizing Octopus 900 visual field testing and optical coherence tomography (OCT), the research established correlations between functional and structural changes in optic nerve regions in patients with GO and patients with GO with elevated IOP (GO IOP) groups. A comparison with primary open-angle glaucoma (POAG) was conducted in a cohort of 182 subjects. The study identifies optic nerve head parameters that effectively differentiate changes in GO and GO IOP groups. In the GO group, the strongest correlation between structural and functional changes was observed in sector 7, while in the GO IOP group, it was in sectors 1 and 7. For POAG, correlation was found in six sectors. Elevated IOP in GO correlates with structural and functional impairments similarly to early glaucoma. Risk factors for GO-related elevated IOP included older age, longer duration of thyroid disease, and higher anti-thyroglobulin values. The study highlights the significance of regular IOP measurements, visual field assessments, and OCT examinations in GO patients. Early antiglaucoma intervention is warranted when characteristic structural and functional changes and/or risk factors are identified.
ABSTRACT
INTRODUCTION: Goldmann applanation tonometry (GAT) is named as a gold standard for intraocular pressure (IOP) measurement. AIM: To assess the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over hydrogel and silicone hydrogel contact lenses (CLs) of different powers. METHODS: This study included 117 eyes of 61 patients (12 male, 49 female), all habitual wearers of hydrogel and silicone hydrogel CLs, and none previously diagnosed with glaucoma, ocular hypertension or anterior surface disease. Five IOP measurements were taken over each eye using a rebound tonometer (Icare): with soft CLs in situ and then repeated without CLs. Lens power ranged from -9.50 to +10.00 spherical diopters and to a maximum of -0.75 cylinder diopters. RESULTS: A significant positive correlation was found between IOP measurements with and without CLs. The difference between IOP measurements with (mean 20.74±5.19 mmHg) and without (mean 18.79±4.36 mmHg) CLs was found to be 1.95 mmHg (P <0.01). Statistical analysis was performed using the paired t-test and a correlation coefficient was calculated (r = 0.59; P <0.001). We have observed that increase in central corneal thickness (CCT) correlates positively with increase of measurement error of rebound tonometry (r = 0.43; P <0.001). CONCLUSION: We have shown good reliability of IOP measurements over CLs of different materials and thickness profiles while using rebound tonometer which makes it a feasible and accurate method for clinical purposes.
