Pterygium causes visual disturbances due to:
Ref: Basak Essentials of Ophthalmology 5th edition pg no 153 -156Explanation:PterygiumElastotic degeneration of the subconjunctival tissue which proliferates as a triangular fold of tissue to invade the cornea.Etiology:Idiopathic.Exposure to UV raysHot sandy weather are risk factorsPingecula may be a precursorSymptoms:Appearance of a massDefective vision - Due to astigmatism f with the rule astigmatism] & obstruction of the papillary area by the tissue invasionDiplopia - due to symblepliaron causing restricted ocular movementsSigns:Most common on the nasal side.Double Pterygium - When pterygium is seen on both nasal & temporal sideThree PartsHead - apex of the triangular mass.Neck - constricted portion at the limbus,Body - the remaining bulky part & cap - infiltration in front of the head."Stocker's line"- iron deposit infront of cap in the corneal epithelium.Stages:Progressive - fleshy, thick with prominent vascularity, gradually increases in size. Cap is presentAtrophic - Thin, attenuated with poor vascularity. Stationary.Management: Pterygium excision with conjunctival autograft/ amniotic membrane graft
Astigmatism
Myopia
Hypermetropia
Keratoconus
Degenerative Conditions