Corneal and lens clarity in patients with chronic obstructive pulmonary disease

The effect of smoking on corneal densitometry and endothelial cell morphology

PURPOSE

We investigated corneal endothelial morphology and corneal densitometry in smokers and compared our results with findings observed in non-smokers.

MATERIALS AND METHODS

This cross-sectional observational study included 100 participants (50 smokers, 50 non-smokers) aged 18-80 years in whom corneal endothelial morphology was analysed using a non-contact Tomey EM-4000 specular microscope (Tomey Corporation, Japan). The Pentacam HR system was used to measure corneal densitometry spatially in three concentric zones (from the centre to the periphery) and at three different corneal depths (from the anterior to the posterior aspects). Endothelial morphology findings and corneal densitometry values were recorded in all participants, and these results were compared between smokers and non-smokers.

RESULTS

Endothelial morphology and corneal densitometry analysis showed significantly lower endothelial cell counts (Num) in smokers (228 cells/mm² vs. 246 cells/mm², p = 0.02) in addition to increased maximum cell area (Max) values (986.5 µm² vs. 935 µm², p = 0.04). We observed no statistically significant intergroup difference in corneal densitometry values (p > 0.05 for each zone); however, we observed a moderately positive correlation between densitometry values in the 6-10 mm concentric zone and between the all total corneal zones and number of pack-years in smokers.

CONCLUSIONS

Our study highlights that among the morphometric corneal endothelial variables analysed in this study, only the Num value was significantly correlated with smoking. We observed no statistically significant intergroup difference in corneal densitometry values in this study; however, a positive correlation was observed between the number of pack-years and corneal densitometry findings. Therefore, as the pack-years increase, the increase in corneal densitometry values may indicate a decrease in corneal clarity, considering the possible contribution of secondary factors such as age.

Evaluation of the corneal endothelium by specular microscopy in patients with chronic obstructive pulmonary disease

OBJECTIVE

The objective of this study is to evaluate the corneal endothelium in patients with chronic obstructive pulmonary disease (COPD) using a specular microscope.

METHODS

The right eyes of 64 patients with a COPD diagnosis and 65 healthy individuals were evaluated. Cell density (CD) (cell/mm² ), corneal thickness (CT) (μ), hexagonal cell ratio (%), and coefficient of variation (cell area standard deviation/mean cell area, μm² ) were analyzed by specular microscopy (SM).

RESULTS

The CT was significantly reduced in the COPD group compared with the control group (P = 0.021). Moreover, a significant difference was found between the COPD group and the control group in terms of corneal endothelial CD (P = 0.011), hexagonal cell ratio (P = 0.008), and coefficient of variation (P = 0.012).

CONCLUSION

The corneal endothelial structure was significantly deteriorated in patients with COPD compared with the control group. SM is a valuable method that could be used in treatment and follow-up of corneal endothelium in patients with COPD.