ABSTRACT
BACKGROUND: Patients with Sjögren's syndrome and polyneuropathy more frequently develop cranial nerve affection when compared to patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We therefore aimed to analyze trigeminal corneal nerve fibre characteristics in both patient groups. METHODS: A total of 26 patients with Sjögren's syndrome associated neuropathy and 29 patients with CIDP were recruited at our university hospital and compared to 6 healthy controls. Dry eye symptoms and signs were assessed via clinical examination and the Ocular Disease Surface Index questionnaire. Trigeminal corneal nerve fibres were analyzed via corneal confocal microscopy (CCM) as a non-invasive in vivo microscopy. RESULTS: CCM revealed significantly reduced corneal nerve fibre density and corneal nerve fibre main branch density in the Neuro-Sjögren group when compared with healthy controls. There were no significant group differences between the Neuro-Sjögren and the CIDP group for any of the microscopic parameters. Dry eye assessment showed similarly reduced scores for both patient groups, while healthy controls showed better results for objective dry eye signs. There was no correlation between microscopic parameters of the corneal confocal microscopy and parameters of dry eye assessment. CONCLUSIONS: Our data revealed trigeminal corneal nerve affection in patients with neuropathy associated with Sjögren's syndrome and patients with CIDP detected by CCM. No difference was found between both neuropathy groups indicating that CCM is not able to distinguish between both entities.
ABSTRACT
PURPOSE: To evaluate the effect of corneal density and thickness on the accuracy of tonometry readings obtained via three most used techniques. METHOD: Intraocular pressures of 45 patients' right eyes were measured using Goldmann Applanation, iCare, and non-contact tonometry methods. Corneal parameters were obtained using the Pentacam Camera System. Data obtained were analyzed using Paired t Test, Pearson's correlation coefficient, multiple linear regression analysis, and Bland-Altman plots. RESULTS: The mean corneal thickness was 545.4 ± 3.93 µm. The mean corneal density of total, stromal, 0-2 mm, and 2-6 mm zones were 27.85 ± 6.23 GSU, 24.61 ± 6.05 GSU, 20.76 ± 2.96 GSU, and 20.81 ± 3.51 GSU respectively. IOP readings had a statistically significant correlation with corneal stromal thickness, as well as with total and stromal density. The stromal density, however, showed higher correlation with the three tonometry methods than did the total density (iCare: - .482 (0.001) stromal density versus- .464 (0.001) total density, NCT: - .376 (0.011) versus - .353 (0.017), GAT: - .306 (0.041) versus - .296 (0.048)). Statistical differences were found in comparing the iCare readings with GAT (P < 0,00) and with NCT (P < 0,00), with mean differences of 1.8 mmHg ± 2.6 and 2.0 mmHg ± 2.6 respectively. GAT and NCT measurements showed no statistical difference (P > 0.05). CONCLUSION: This study shows that both central corneal thickness and stromal density are significant influential factors of reliable IOP readings. It is necessary to consider more corneal biomechanical properties, as well as exercise a high degree of caution in any new attempts towards adjusting an IOP-correction equation.
