Related Experiment Video
Updated: Jun 8, 2026

Glaucoma-inducing Procedure in an In Vivo Rat Model and Whole-mount Retina Preparation
Published on: March 12, 2016
Association of CYP2D6 single-nucleotide polymorphism with response to ophthalmic timolol in primary open-angle
Hongzhi Yuan1, Minbin Yu, Yangfan Yang
1State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University , Guangzhou, People's Republic of China.
Objectives:
We aimed to investigate whether CYP2D6 polymorphisms were associated with the intraocular pressure (IOP)-lowering effect and systemic complications (especially bradycardia) of ophthalmic timolol.
Methods:
One hundred twenty-three primary open-angle glaucoma subjects (123 eyes) were treated with 0.5% aqueous formulations of ophthalmic timolol. IOP and heart rate were measured before and after timolol administration. DNA was extracted from venous leukocytes of all the subjects. Two single-nucleotide polymorphisms (SNPs) of CYP2D6, for example, rs16947 (2850C>T, R296C) and rs1135840 (4180C>G, S486T), were detected by restriction fragment length polymorphism analysis.
Results:
Neither rs16947 (P = 0.339) nor rs1135840 (P = 0.903) genotype was statistically correlated with the IOP-lowering effect of timolol eye drops. The rs16947 genotype was significantly associated with occurrence of bradycardia in primary open-angle glaucoma patients (P = 0.021). The patients with rs16947 CT (P = 0.043) or TT (P = 0.043) were more inclined to bradycardia than those with rs16947 CC, although there was no significant difference between CT and TT (P = 0.177). The analysis of variance showed no significant difference in heart rate (P = 0.559) among GG, GC, and CC groups.
Conclusions:
CYP2D6 SNP rs16947 may confer susceptibility to timolol-induced bradycardia. Patients with CC genotype were unlikely to suffer from timolol-induced bradycardia, whereas those with TT genotype were found to suffer from timolol-induced bradycardia.
Related Concept Videos
Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Ophthalmic Drug Delivery Systems
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Angle Closure Glaucoma: Treatment