Seven Corners gave written preapproval for the procedures recommended by Dr. Brian Chen. To be safe, An Tran called the insurer “many times” to confirm it would cover the expense, but no one she spoke with would give her a definitive answer, she said. Chen, however, assured An that insurance companies typically covered the treatment, which was pretty routine. On April 19, Tran underwent the first of three eye surgeries to resolve the glaucoma. The surgeries — the last was on July 19 — were successful. And then on Aug. 5, Seven Corners sent An Tran a denial of service letter.