What does the light laps do in the spider room?

[Gian]

I light them, shows a eyes, and eye brows, any meaning?

[Umbrella Incorporated]

It's the key to figure out the code to the chemical room where you mix the V-Jolt. If you skip that part and want to take on Plant 42 directly, just ignore them. But if you want to access that room then you need to figure out the puzzle.

1) Each of the candles show a shadow eye image beneath them, that relates to the three eye symbols on the door panel.
2) Each candle is also a certain color (green, orange or red). This indicates which ball on the pool table corresponds to the number for that eye symbol.
3) The pool table shows which colors go with which numbers, ultimately giving you the passcode.

The easy thing to remember is that the numbers will always be the same (3, 5 and 6) but will not always match the same symbols. The easiest thing to do is simply plug in the numbers and retry them in sequence until you get the right code, which doesn't take long since there's only a maximum of six possible combinations.
3, 5, 6
3, 6, 5
5, 3, 6
5, 6, 3
6, 3, 5
6, 5, 3

[Hollapeno]

What Umbrella said. If you wish to tackle Plant 42 head on there is no need to take heed.

[SaltyPeanuts]

The literal meaning of the images is that the 'brows' of the eye indicate the order to input the numbers.

The first # will have 1 brow, the second 2 brows, the third will have 3 brows.
The color of the eyes indicates the color of the ball on the pool table.

So if you combine these two rules- you have the numbers (on the balls) and the order (# of brows on the eyes) in which they must be input into the control panel.

[V I D A L]

Also, if you're playing as Chris, you can ignore that altogether. With Chris the only option is to fight the plant as he doesn't have enough chemical knowledge to deal with the poison. Only Jill has the option to kill the plant smart or kill the plant loud.