Phototherapy uses specific light wavelengths to treat medical conditions, primarily neonatal jaundice (blue-green light) and skin diseases (ultraviolet light). For bilirubin reduction, the most effective spectrum is blue light between 430–490 nm, with peak efficacy at 460–490 nm. Dermatological phototherapy uses UVA (320-400 nm) or Narrowband UVB (311-313 nm). 

Key Phototherapy Spectra

• Neonatal Jaundice (Hyperbilirubinemia):
  • Optimal Range: 430–490 nm (Blue-Green Light).
  • Peak Efficacy: 460–490 nm or 450-460 nm.
  • Mechanism: Converts toxic bilirubin into water-soluble photo-isomers for excretion.
  • Types: Special blue fluorescent tubes or LEDs.
• Dermatology (Skin Conditions - Psoriasis/Eczema):
  • Narrowband UVB (NB-UVB): 311–313 nm (Most common, high efficiency).
  • Broadband UVB (BB-UVB): 270–350 nm.
  • UVA-1: 340–400 nm (Deep penetration for severe skin conditions).
  • PUVA: UVA combined with Psoralen.
• Mental Wellness (SAD):
  • Bright white light (often ~10,000 lux) or blue light to regulate serotonin and melatonin. 

Key Considerations

• Irradiance: Higher intensity light in the blue spectrum is more effective.
• Skin Surface Area: Larger exposed surface area improves treatment efficiency.
• Distance: Optimal distance for neonatal phototherapy is often 30-40 cm.
• Safety: UV phototherapy is carefully controlled, whereas jaundice phototherapy generally avoids harmful, high-energy ultraviolet wavelengt