Table 5.

The Effect of an Increase in Ambient Air Pollution on the Thickness of Each Retinal Layer

	Inner Retinal Layers			Outer Retinal Layers
Air Pollutants (µg/m3)	RNFL	GCIPL	INL	OPL+ONL	PIS	POS	RPE
PM2.5	↑↑	↓↓	↓	↓↓	NS	NS	NS
PM2.5 ab	↓	NS	↓	↓	NS	↑	NS
PM2.5–10	NS	NS	NS	NS	NS	NS	NS
PM10	↓↓	↑	↓	NS	NS	NS	NS
NO2	NS	NS	↓↓	NS	NS	↑↑	NS
NOX	↑	↓	↓	↓	NS	NS	NS

The arrows represent either an increase (↑) or decrease (↓) in the thickness of each retinal layer after an increase in exposure to air pollution and indicates a significant association. Double arrows indicate the specific air pollutant has the strongest effect on the individual retinal layer and shows a significant association. For example, of all the air pollutants on GCIPL, the effect of PM_2.5 is the strongest on GCIPL. A nonsignificant association between the air pollutant and retinal layer will be indicated as nonsignificant (NS).

Statistical significance was set at P < 0.001 after Bonferroni correction.