( ( The ( lens constructions ) ) ( ( are ( designed ( to ( form ( a ( concave lens ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN lens) (NNS constructions)) (VP (VBP are) (VP (VBN designed) (S (VP (TO to) (VP (VB form) (NP (DT a) (JJ concave) (NN lens))))))) (. .)))
The lens constructions are designed to form a concave lens.
(ROOT (S (NP (JJ Concave) (NNS lenses)) (VP (MD can) (VP (VB correct) (NP (NN myopia)))) (. .)))