Glowwater Potion is very strong, but early in the run it can be quite difficult to make good use of. Unless you have some cards which gain energy, drawing 10 doesn't actually let you do all that much. In contrast, Fresnel Lens is great to get early in the run, since you still have the entire rest of the run to get offered defensive cards which take advantage of it. I usually take Fresnel Lens here unless I have good energy gain and/or need a potion for an upcoming difficult fight.
You have to give up a lot of max hp to get the lens, but it's quite worth it. Compare 13 hp to 2 hp per block card you play in an act, and you can see that the Lens easily makes up for the health deficit once you add a few blocks. The Lens improves all block generated by a card, so cards that block multiple times like Dodge and Roll or Toric Toughness benefit multiple times from the enchantment. You can get the Fresnel Lens to enchant your defends if you remove and then re-add them with the Pael's Tooth blessing. Since cards can only have one enchantment, the Lens can be a downside if you end up wanting a different enchantment on your block cards.
岩石と静かな水辺が広がる幻想的な風景を抜けると、空虚な光を放つ、沈みゆく灯台が現れた。
足元に溜まっている不気味に発光する水を瓶に汲むか、崩れかけた灯台をよじ登ってレンズを回収するか。 二つに一つだ。
水を汲む
燐光のポーションを獲得。
手近な瓶を使って光る液体を慎重に汲み取った。 その横では、灯台が静かに沈んでいく。
中にいなくて本当に良かった。
よじ登る
フレネルレンズを獲得。 最大HPを13失う。
ずぶずぶと沈んでいく灯台に恐怖を覚えながらも、頂上まで登り詰めた。
明かりが灯る部屋にたどり着き、レンズをこじ開けようとする。 だが、活力を奪う光が生命力を削り取っていく！
ついにレンズをもぎ取ると、灯台はピタリと沈むのをやめた。