What type of treatment is best to get rid of these wrinkles that extend diagonally from lower eye to upper cheek?

Hi Hannah.  The office that told you the lines were from volume loss made a good assessment.  You are very thin and your face has lost collagen and fatty tissue volume.  Our first choice would be Sculptra to replace this lost volume, but other dermal fillers such as Restylane, Perlane and Radiesse are all viable choices as well.  Laser resurfacing is not going to achieve that which you desire because it cannot replace the kind of volume you have lost and you are correct that Botox works on the crow's feet closer to the sides of the eyes.Check the photos at the link below for a similar situation.  

Thank you for the question. The upper cheek area requires a thoughtful approach and I think you are on the right track. Botox can be used for the crow's feet, just lateral to the corner of the eye. For lines that extend further down the cheek, Botox injections can cause unwanted complications. This is where the muscles that control the smile are located, and Botox here can cause an uneven smile or change your mouth movements. For lines in the upper cheek, volume can be very helpful. This can be achieved with traditional fillers, like Juvederm, deeper and longer lasting fillers, like Voluma or Radiesse, or through Sculptra treatment.

Perhaps the botox was not injected to address the lateral line extensions & you need to ask your practitioner if they targeted these lines before seeking another treatment.As these are lines which are visible when you smile - they are dynamic wrinkles & I would recommend botox initially followed by a HA dermal filler to hydrate & volumize with superficial injections in the delicate periocular area.A course of radiofrequency skin tightening is also effective for this area.

Agree that botulinum toxin injection is not a good idea for the lines you are referring to in the lateral cheek area (from smiling).  Dermal filler injection though may be useful.

Typically these larger lines are due to hypertrophy of the musculature underneith as well as some volume loss in the cheeks/temples.  Botox or neuromodulation is a good start but typically will not help the larger lines around the eyes as these are influenced by large muscles that are deeper.  Laser resurfacing and/or radiofrequency or ultrasound devices can help tighten and soften and smoothen the skin.  Filler injection into the mid and lateral cheeks can help lift and superficial injection can help soften the individual.  Overtime, continued neuromodulation treatment will help the muscles around the eyes atrophy and become less prominent and stop any "movement" lines.  Eye creams will not help these larger lines.  Please see a cosmetic dermatologist or plastic surgeon with expertise in filler injection, laser surgery, and eyelid rejuvenation.  I wish you the best of luck, Dr. Emer.