PO-2

• Vitamin A


  Very essential in the synthesis of photopigment which is to sustain photoreceptors
• Retinal dysfunction


  Any disruption in the normal operation of the retina, the light-sensitive tissue layer located at the back of the eye
• Xerophthalmia


  • Refers to the spectrum of ocular disease caused by severe Vitamin A deficiency (VAD)
  • Abnormal dryness of the conjunctiva and cornea of the eye, with inflammation and ridge formation
• Bitot's spots


  • The buildup of keratin located superficially in the conjunctiva of human's eyes
  • They can be oval, triangular or irregular in shape
  • The spots are a sign of vitamin A deficiency and are associated with drying of the cornea
• Keratomalacia (Corneal Xerosis)


  • An eye disorder that involves drying and clouding of the cornea (the clear layer in front of the iris and pupil) due to vitamin A deficiency
  • Night blindness is an early symptom
• Retinitis Pigmentosa


  An Inherited disorder in which there is gradual and progressive failure to maintain the receptor cells
• Macular Degeneration


  • The leading cause of blindness in the elderly
  • The "dry form" involves intraocular proliferation of the cells in the macular area
  • The "wet form" involves the capillaries of the choroid coat invading the macular area and destroying receptor cells and neurons
• Retinal Detachment


  When the neural retina is torn away from the retinal pigment epithelium, there is a loss of vision in the area of detachment
• Diabetic Retinopathy


  • The pathological process involves microaneurysms and punctate hemorrhages in the retina
  • The tiny swollen blood vessels in the underlying choroid coat damage the receptor cells and retinal neurons resulting in blindness in the affected regions