In the bible, dreams, prophecies and visions are almost always symbolic. The only way they can be understood is if the meaning of the symbols is explained.
For example, when Pharaoh had his dream of the sheaves of wheat and the cows, he could not understand it until the interpretation was revealed to Joseph. Likewise King Nebuchadnezzar could not understand his dreams until God revealed the meaning to Daniel.
However, some prophecies employ symbolism that has been used in other parts of the Bible, allowing the diligent to understand at least partially what is meant. Also, the prophet delivering the message sometimes explains part of the symbolism when they deliver the message. Thus in Daniel, beasts represent kingdoms. When we get to Revelation, beasts once again represent kingdoms, not bizarre monsters.
When we get to the lamb that was slain, we look back to other places in the Bible where something has been likened to a lamb. Since John the Baptist called Jesus the lamb that takes away the sins of the world, we have support for the idea that Jesus is the lamb that was slain. Many other parallels - like Jesus' crucifixion and other points of correlation with the Jewish sacrificial system - make this fairly certain.
The eyes and horns also have symbolic meaning. Thankfully the prophet tells us that they are the seven spirits sent out into the world. What the purpose and identity of those spirits is is not immediately disclosed, but it is clear that they are not actual eyes or horns.
It seems to me that these images are mnemonics given to help us to remember the message. Once the believer understands what the symbol stands for, the bizarre and unforgettable image remains as a way to hold onto the meaning. Also, the use of parallel symbolism is a tactic that forces us to revisit other parts of scripture to understand the meaning. It reminds us of what was said before and ties the whole together. To me, what I "see" is the interconnectedness of all God's revelations and the uniformity of his purpose and will across the centuries.
As for breaking the seals, maybe a rams' horn would come in handy...