In my opinion, Piggy's spectacles do have a symbolic significance in this book. I believe that they symbolize science and technology and the power that those things carry.
In the story, Piggy's spectacles are really the only piece of technology on the island. They are powerful because they are the best way of starting a fire.
The spectacles are also connected to science because they belong to Piggy. Piggy is the smartest boy on the island -- he is the one who is closest of any of them to being an intellectual.
The fighting over the spectacles can be seen as a symbol of the ways in which countries fight over things that give them technological power.
Yes, Piggy's glasses do have a symbolic significance in the Lord of the Flies. Piggy's glasses are a symbol of vision and truth. Piggy is the most intellectual of the boys who believes that though they are on an island, they should continue to behave in a civilized manner with social rules and expectations. Though his intelligence is greater than the rest of the group, he lacks the leadership qualities that would have made his voice heard. Piggy's visions and truths were not respected due to his physical frailty and perhaps the belittlement the nickname "Piggy" brings with it.