Abstract
Purpose: :
To investigate corneal biomechanical properties in patients treated with oral hydroxychloroquine (HXC).
Methods: :
Thirty-three eyes of 33 patients taking HXC orally, and 92 control eyes have been included in this cross-sectional case-control clinical study. Patients performed a complete ophthalmological examination including central corneal thickness measurements (CCT). Corneal Hysteresis (CH) and Corneal Resistance Factor (CRF) were measured by the Ocular Response Analyzer, (ORA, Reichert) and intraocular pressure was measured both by Goldmann Applanation Tonometry (GAT) and by ORA (IOPcc).
Results: :
CCT and CH were found to be significantly higher among cases than control eyes (562.6±25.6 vs 541.8±36.4 µm, p<0.001 and 11.4±1.2 vs 10.5±1.6 mmHg, p=0.002). Also CRF was found to be higher in cases than in controls (11.5±1.4 vs 10.7±1.8 mmHg, p=0.012). After matching cases with a subgroup of controls for CCT , CH was still found to be higher in cases while no CRF significant differences were anymore found suggesting that CRF might be more related to CCT than CH. Using a linear regression approach a stronger relationship between CRF and CCT was also observed (R2=0.40, p<0.001) compared to that between CCT and CH (R2=0.17, p<0.001). The difference between GAT and IOPcc was statistically lower in cases than in control eyes (-1.0±3.0 vs -3.7±2.3 mmHg, p<0.001). The difference between GAT and IOPcc was significantly related to CH and this relationship was stronger after adjusting for CRF both in cases (R2=0.40, p<0.001) and in controls (R2=0.33, p<0.001). Dosage and duration of hydroxychloroquine therapy seemed not to influence corneal biomechanics.
Conclusions: :
Patients treated with oral HXC have thicker corneas and higher CH and CRF than controls. After matching cases and controls for CCT only CH remained significantly higher, suggesting that HXC oral therapy affects independently corneal thickness and CH. The influence of CH and CCT changes on the accuracy of IOP readings and as potential risk factors for other diseases need further investigations.
Keywords: cornea: clinical science