Vitreous liquefaction (synchysis)
• Most common degenerative change
• Causes: Senile, myopic degeneration, post- inflammatory, post-traumatic.
Posterior vitreous detachment (PVD)
• PVD with vitreous liquefaction (synchysis) and collapse (syneresis) is of common occurrence in majority of the normal subjects above the age of 65 years.
• Flashes of light and floaters may be associated
• A ring like opacity (Weiss reflex) representing a ring of vitreous attachment at the optic disc margin is pathognomic.
• May be complicated by retinal break, retinal and/ or vitreous haemorrhage and cystoid maculopathy.
• Causes are diabetic retinopathy, Eales’ disease, trauma, retinal breaks and/or posterior vitreous detachment, anaemia, leukaemia and sickle cell retinopathy, central retinal vein occlusion, and bleeding disorders – haemophilia, purpura.
• Complications include retinitis proliferans, vitreous liquefaction and degeneration, and ghost cell glaucoma in aphakes.
• Vitrectomy is indicated if vitreous haemorrhage does not absorb in three months.
Persistent hyperplastic primary vitreous
• Usually unilateral
• Typically presents as a white reflex in pupil
• Associations are: Long ciliary processes, microphthalmos, cataract, glaucoma, and vitreous detachment
• Along with lensectomy
• Vitreous haemorrhage not getting absorbed in 3 months
• Proliferative retinopathies
• Dropped nucleus and intraocular lens
• Intraocular foreign bodies
• Vitreous amyloidosis.
• Synchysis (liquefaction) and syneresis (collapse) are the two most common degenerative changes in the vitreous gel.
• The optimum time for vitrectomy in a patient of bacterial endophthalmitis not responding to conservative treatment is 24 hours after the intravitreal injection of antibiotics.
• Vitreous gel never regenerates.
• The strongest attachment of the vitreous is to the ora serrata (vitreous base attachment).
• Most common cause of vitreous haemorrhage is trauma.
• Most common cause of spontaneous vitreous haemorrhage is proliferative diabetic retinopathy.