Comparison of corneal biomechanical properties in normal tension glaucoma patients with different visual field progression speed

AIM：To compare the corneal biomechanical properties difference by ocular response analyzer（ORA） in normal tension glaucoma（NTG） patients with different visual field（VF） progression speed. METHODS：NTG patients with well-controlled Goldmann applanation tonometer（GAT） who routinely consulted Kitasato University Hospital Glaucoma Department between January 2010 and February 2014 were enrolled.GAT and ORA parameters including corneal compensated intraocular pressure（lOPcc）,Goldmann estimated intraocular pressure（lOPg）,corneal hysteresis（CH）,corneal resistance factor（CRF） were recorded.VF was tested by Swedish interactive threshold algorithm（SITA）-standard 30-2 fields.All patients underwent VF measurement regularly and GAT did not exceed 15 mm Hg at any time during the 3y follow up.Patients were divided into four groups according to VF change over 3y,and ORA findings were compared between the upper 25th percentile group（slow progression group） and the lower 25th percentile group（rapid progression group）.RESULTS：Eighty-two eyes of 56 patients were studied.There were 21 eyes（21 patients） each in rapid and slow progression groups respectively.GAT,lOPcc,lOPg,CH,CRF were 12.1＋1.4 mm Hg,15.8±1.8 mm Hg,12.8±2.0 mm Hg,8.4±1.1 mm Hg,7.9±1.3 mm Hg respectively in rapid progression group and 11.5±1.3 mm Hg,13.5±2.1 mm Hg,11.2±1.6 mm Hg,9.3±1.1 mm Hg,8.2±0.9 mm Hg respectively in slow progression group（P=0.214,〈0.001,0.007,0.017,0.413,respectively）.In bivariate correlation analysis,lOPcc,lOPcc-GAT and CH were significant correlated with m△MD（r =-0.292,-0.312,0.228 respectively,P =0.008,0.004,0.039 respectively）.CONCLUSION：Relatively rapid VF progression occurred in NTG patients whose lOPcc are rather high,CH are rather low and the difference between lOPcc and GAT are relatively large.Higher lOPcc and lower CH are associated with VF progression in NTG patients.This study suggests that GAT measures might underestimate the IOP in such patients.

Switching Study of Tafluprost/Timolol Fixed-Combination Ophthalmic Solution, Following Unfixed Combination of Tafluprost Ophthalmic Solution 0.0015% and Timolol Ophthalmic Gel-Forming Solution 0.5%

Purpose: Fixed-combination medication to treat glaucoma can reduce intraocular pressure (IOP) without negative effects of concomitant medication. Tafluprost/timolol fixed-combination ophthalmic solution (TTFC) has been reported to show similar effectiveness in lowering IOP, compared with concomitant use of its component drugs, tafluprost and timolol. However, the difference in IOP-lowering effects between TTFC and concomitant use of tafluprost and gel-forming timolol is unknown. Hence, we conducted this switching study from tafluprost and gel-forming timolol to TTFC in glaucoma patients undergoing multi-drug therapy. Design: Multi-center, open-label, interventional clinical study. Methods: Twenty-eight patients (28 eyes;safety analysis set) with primary open-angle glaucoma and ocular hypertension, who had completed the 4-week-concomitant phase of tafluprost and gel-forming timolol, were treated for 8 weeks with TTFC. IOP, adherence, ocular surface safety, and the usability of ophthalmic solution were compared before and after switching. This study was approved by the ethics committees of Kitasato University Hospital and all other study sites. All patients provided written informed consent to participate. Results: IOP at 8 weeks after switching was significantly lower than before switching (P = 0.0001) in the efficacy analysis set (n = 24). The self-reported adherence rate remained high after switching;moreover, there was no meaningful change in ocular surface safety. Patient questionnaires regarding usability of medication revealed that 85.7% of patients preferred their instillation prescription after switching, including TTFC. Among the safety analysis set (n = 28), no adverse events were reported in relation to the study drug. Conclusion: TTFC showed greater IOP reduction than concomitant therapy. Thus, TTFC may be a better option in glaucoma patients than concomitant therapy.