Retinal nerve fiber layer thickness and retinal vascular caliber alterations in coal miners in northern China: a community-based observational study
Authors:   Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Capital Medical University, Beijing 100730, China, Yang Jing-Yan , Wang Qian ,   Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Capital Medical University, Beijing 100730, China, Li Yang ,   Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Capital Medical University, Beijing 100730, China, Yan Yan-Ni ,   Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Capital Medical University, Beijing 100730, China, Wang Ya-Xing ,   Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Wu Shou-Ling ,   Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing 100730, China, Wei Wen-Bin ,   Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Capital Medical University, Beijing 100730, China
Published: December 2021

AIM: To evaluate retinal nerve fiber layer thickness and retinal vascular caliber alterations in coal mine workers.
METHODS: The community-based observational cross-sectional study included 4004 participants of a sub-population of the Kailuan Study. All the study participants underwent structured interviews with a standardized questionnaire, fundus photography and spectral-domain optical coherence tomography (OCT) examinations performed by trained doctors.
RESULTS: The retinal nerve fiber layer thickness was significantly higher (P=0.006) and the central macular thickness was lower in coal miners (n=659, 51.0±7.8y) as compared to the control (working above the ground; n=477, 51.8±7.5y; P=0.032). Additionally, the downhole workers showed a significantly thicker retinal artery (P=0.012) and vein diameters (P&#x003C;0.001). In multivariable regression, a thicker retinal nerve fiber layer was associated with a higher cumulative silica dust exposure (P=0.005) after adjusting for younger age and larger spherical equivalent. In a reverse pattern, a higher cumulative silica dust exposure (P=0.004) was significantly associated with a thicker retinal nerve fiber layer after adjusting for age, high-density lipoproteins and uric acid. Wider retinal vein diameters were associated with higher cumulative silica dust exposure (P=0.036) after adjusting for younger age and larger spherical equivalent.
CONCLUSION: The retinal vessels diameters and retinal nerve fiber layer thickness are significantly thicker in long term of coal mining. The results of our study indicate that underground working environment may lead to retinal vessel dilation and inflammation. Thus, ocular examination might be needed within coal miners in order to monitor the occupational eye health as well as the incidence and progression of eye diseases.