The short answer
Tear-trough filler is a hyaluronic acid gel placed deep against the bone beneath the lower orbital rim. It restores volume to a hollow under-eye, reducing the shadow that the hollow casts. It does not improve skin texture, fine lines, or pigmentation.
Polynucleotides are purified salmon DNA fragments injected superficially into the under-eye skin. They stimulate collagen and elastin production, improving skin texture, fine lines, and dehydration. They do not add volume.
Many under-eyes need both. Some under-eyes need neither — and a conservative practitioner will sometimes say so.
What is actually causing your under-eye concern?
Before choosing a treatment, identify the cause. The under-eye area presents three overlapping concerns that look similar on a first glance but require different treatments:
Volume loss (the hollow)
The bony orbital rim becomes visible as the soft tissue below the eye thins or retracts with age. A shadow forms in the depression between the lower eyelid and the cheek. This is a structural problem and the right tool is filler placed deep against the bone — or a surgical fat-repositioning lower blepharoplasty in more significant cases.
Skin quality decline (the crepiness)
The thin under-eye skin loses collagen, elastin, and hydration. Fine lines appear when the patient smiles. The surface looks crepey, dull, or papery. This is a skin quality problem and the right tool is a regenerative treatment — polynucleotides, PRP, or topical retinoids — not filler.
Pigmentation (the dark circle that is genuinely dark)
The under-eye skin is genuinely darker than the surrounding face due to melanin deposition, post-inflammatory hyperpigmentation, or visible vascular structures (the orbicularis oculi muscle and underlying veins showing through). This is a pigment / vascular problem and the right tool is laser (Iris Dye-VL or similar) for pigment, vascular laser (VascuPen, Iris Dye-VL) for vascular shadowing, or topical depigmenting agents. Filler does not fix pigmentation; polynucleotides only marginally improve it.
Many under-eyes show all three problems in combination. The treatment plan therefore combines tools.
Tear-trough filler — when it is the right answer
Good candidates for tear-trough filler typically have:
- A clear bony orbital rim visible through the skin — the hollow is anatomic, not just dark
- Thin, taut skin without significant laxity (loose skin can produce Tyndall effect — a bluish discolouration when HA filler shows through thin skin)
- Minimal lower-eyelid fat prolapse — bags that protrude further than the orbital rim are a surgical problem, not a filler problem
- No fluid retention at the time of treatment — chronic puffy bags from allergy, kidney function, or sleep posture are not a filler indication
The injection technique matters more here than almost anywhere on the face:
- Deep placement against the periosteum (the bone covering), well below the level of the angular artery
- Cannula technique (a blunt-tipped tube rather than a sharp needle) reduces vascular event risk
- Small volumes — typically 0.3 to 0.5 mL per side initially, never the whole syringe in one visit
- Conservative product choice — a low-particulate, low-hygroscopic HA designed for thin skin
- Hyaluronidase on-site — non-negotiable; a clinic that cannot reverse the product in 60 seconds should not be injecting this area
Polynucleotides — when they are the right answer
Polynucleotides are the right tool when the under-eye concern is primarily skin quality rather than volume:
- Fine crepey lines visible when smiling that persist at rest
- A dull or dehydrated appearance to the under-eye surface
- Mild laxity in the lower eyelid skin without prominent fat bags
- Patients who are not candidates for filler but want to do something for the area
A standard polynucleotides protocol is 3 sessions, 3 weeks apart, with the effect peaking 8 to 12 weeks after the final session. Maintenance is recommended every 6 months. The most common side effects are injection-site swelling and bruising lasting 24 to 72 hours.
When you need both
Many patients in their late thirties and forties benefit from a combination:
- Tear-trough filler to address the volume hollow (single session, settle at 2 weeks)
- Polynucleotides course starting 4 to 6 weeks after filler — improves the skin quality of the under-eye surface and the filler-treated area together
Reversing this sequence is fine for some patients (treating skin quality first, then assessing whether volume is still needed). Treating both on the same day is generally avoided because each treatment produces some swelling and assessing the result of either is harder when both are settling.
When neither is the right answer
A consultation that ends with “I would not inject under your eyes” is more common than patients expect. Reasons include:
- Prominent fat bags below the orbital rim — these are a surgical problem (lower blepharoplasty with fat repositioning) and filler around them typically makes them more prominent rather than less
- Significant lower-eyelid laxity — the skin will Tyndall, the filler will migrate, the result will look worse than no treatment
- Pigmentation as the dominant concern — filler does not lighten pigment; the right treatment is laser or topical depigmenting
- Fluid retention — the area looks puffy or hollow depending on the day; filler does not solve this and may make the puffy phase look worse
The discipline to decline a treatment is the strongest signal of a doctor’s incentive structure being aligned with the patient’s outcome rather than with the day’s revenue.
Bottom line
The under-eye is not one problem with one treatment. It is three overlapping problems (volume, skin quality, pigment) any of which can dominate in any given patient — and any of which can be solved with the wrong tool by a practitioner who is not paying attention. The correct sequence is assess first, then choose the tool — or sometimes, assess and recommend no treatment at all.
