Role of Optical Coherence Tomography to Measure Retinal Nerve Fiber Layer Thickness in Patient With Chronic Obstructive Pulmonary Disease.

Abstract

Aim: This study aimed to measure retinal nerve fiber layer thickness with spectral domain optical coherence tomography in patients diagnosed with stable chronic obstructive pulmonary disease. And, comparing the RNFL thickness of stable patients with mild to moderate COPD and severe to very severe COPD patientsPatients and methods: In this prospective case-control study, a total of 120 patients with chronic obstructive pulmonary disease (COPD) have been selected for measurement of retinal nerve fiber layer on spectral domain-optical coherence tomography (SD-OCT). This study included 120 eyes of participants among which 80 were COPD patients (G1) and 40 were healthy participants (control group: G2). The G1 group is further sub-classified into G1A included 40 eyes of 40 patients with mild to moderate COPD and G1B included 40 eyes of 40 patients with severe to very severe COPD. To determine the hypoxic status of patient arterial blood gas analysis was done. The subfoveal choroidal thickness and retinal nerve fiber thickness were calculated using spectral domain OCT, and these readings of OCT are compared with COPD.Results: There was no statistically significant difference between groups according to demographic data. Mean peripapillary retinal nerve fiber layer (RNFL) thickness on SD-OCT was statistically significantly thinner in mild to moderate COPD (106.76±4.39) group and severe to very severe COPD (100.75±4.66) group than in the control group (108.51±4.39); this thinning was more pronounced with increase in the severity of COPD. On comparing macular thickness between three groups, it was found that there were no statistically significant differences in macular thickness (MT) (p=0.684). Subfoveal choroidal thickness (SFCT) was significantly thinner in the COPD groups compared to the control group.Conclusion: Changes in the SD-OCT and retinal nerve fiber layer (RNFL) thickness could be used as indicators for the severity of COPD. And, it can also aid in the early intervention to hypoxic changes in the retina there by decreasing the chances of visual field defect