Definitions

  1. Accomodation

    • It is the ability of eye to increase its converging power so as to focus diverging rays coming from near object on the retina to see it clearly.

  2. Agonist

    • It is the primary muscle moving the eye in a given direction.

  3. Amaurosis Fugax

    • It is painless, transient unilateral loss of vision, often described as a curtain coming down over the eye from top to bottom or vice versa.

  4. Amblyopia

    • It is reversible condition with unilateral or bilateral decrease of visual function caused by form vision deprivation and / or abnormal binocular interaction that cannot be explained by a disorder of ocular media or visual pathway itself.

  5. Antagonist

    • It is the muscle that acts in opposite direction to the agonist.

  6. Applanation

    • It measures the force required to flatten a small standard area of the cornea (3.06 mm ).

  7. Bitot’s spot

    • They are small , triangualr, white, foamy patches on the outer & inner sides of the cornea, covered by a material resembling dried foam, not wet by the tears, are due to gas production by C.xerosis present in the horny epithelium.

  8. Cataract

    • It is due to formation of opaque lens fibre / congenital / developmental or due to degenerative process leading to opacification of normally formed transparent lens fibres ( acquired cataract ).

  9. Concretion

    • It is accumulation of inspissated mucus & dead epithelial cells into the glands of Henle.

  10. Convergence

    • It is simultaneous adduction ( inward turning ) of both the eyes.

  11. Corneal Ulcer

    • It is the epithelial defect with infiltration & resultant melting of underlying & surrounding connective tissue in response to the release of enzymes from endogenous sources in response to inflammation or from exogenous organisms ( bacteria, amoeba & fungi ).

  12. Dislocation / Luxation

    • It is complete displacement of the lens from its normal position ( in patellar fossa ) due to complete rupture of the lens zonules.

  13. Divergence

    • It is outward movement from a convergent position of both the eyes.

  14. Endophthalmitis

    • It is the inflammation often purulent involving all intra ocular tissues except sclera.

  15. Fluoroscein Angiography

    • It is photographic surveillance of the passage of flouroscein through the retinal & choroidal circulation following i.v. injection.

  16. Fluoroscence

    • It is the property of certain molecules to emit light of a longer wavelength when stimulated by light of a shoter wavelength.

  17. Follicle

    • It is aggregation of lymphocyte & other cells in adenoid layer with central core of mononuclear histiocyte, lymphocyte & large multi nucleated cells called Leber’s cells.

  18. Giant Tear

    • It is limbus parallel tear of greater than 90° / 3 clock hours or more of the globe circumference.

  19. Glaucoma

    • It is chronic progressive neuro degenerative disease of the optic nerve caused by group of ocular conditions which is characterised by i. accelerated ganglion cell death, ii. Subsequent axonal loss, iii. Optic nerve damage & iv. Eventual visual field loss; all of which can be arrested or diminshed by adequate lowering of Intra Ocular Pressure.

  20. Glaucoma : Normal / Low Tension

    • It is chronic progressive anterior optic neuropathy characterised by i. Intra ocular pressure <21 mm on diurnal testing ii. Glaucomatous optic disc damage & visual field loss, iii. Open drainage angle on gonioscopy & iv. Absence of secondary cause for glaucomatous disc damage.

  21. Glaucoma : POAG suspect

    • It is the condition characterised by i. normal intra ocular pressue, disc, & visual field, ii. > 270° irido trabecular contact & iii. Absence of peripheral anterior synechia.

  22. Glaucoma : Primary Angle Closure Glaucoma PACG

    • It is the condition characterised by i. > 270° of irido trabecular contact, ii. Increased intra ocular pressure & iii. Optic nerve & visual field damage.

  23. Glaucoma : Primary Open Angle POAG

    • It is chronic progressive anterior optic neuropathy accompanied by i. characteristic cupping & atrophy of the optic disc, ii. Visual field loss, iii. Open angles on gonioscopy, iv. No obvious causative ocular or systemic condition.

  24. Hyperflouroscence

    • It is the increased fluoroscence due to enhanced visualisation of a normal density of fluoroscein in the fundus or an absolute increase in the fluoroscein content of the tissues.

  25. Hypofluoroscence

    • It is decreased or absence of the fluoroscence due to either masking of normal density of fluoroscein in a tissue or inadequate perfusion of tissue with resultant low flouroscein content.

  26. Hypopyon

    • In keratitis, if irritation is great , leucocytes poured out by the vessel pass into the aqueous & gravitate to the bottom of anterior chamber known as hypopyon.

  27. Indentation

    • It measres the amount of indentation of the globe in response to a standard weight applied to the cornea.

  28. Keratic Precipitates

    • They are small accumulations of inflammatory cells derived from uvea which adhere to the mid & inferior corneal endothelium. It indicates uveal inflammation.

  29. Keratitis

    • It is focal areas of active stromal inflammation composed of accumulations of leucocytes & cellular debris associated with corneal edema & ciliary congestion.

  30. Keratoconus

    • It is the non inflammatory, non infective, bilateral, progressive disorder in which cornea assumes conical shape secondary to stromal thinning & protrusion.

  31. Keratoplasty

    • It is operation in which abnormal host tissue is replaced by healthy donor cornea.

  32. Keratoplasty : Graft failure

    • A graft which never clears remaining thickened post operative, due to some defect in donor tissue, poor eye banking or surgical trauma to endothelium but never immuno pathophysiologic process.

  33. keratoplasty : Graft rejection

    • It is a specific irreversible process immunologically mediated in which a graft having been clear for atleast several weeks, suddenly succumbs to graft edema in conjunction with inflammatory signs.

  34. Keratoplasty : Lamellar

    • It is the corneal transplant procedure to replace only the diseased part & leave the recipient’s normal anatomic layers intact. Advantage : leave behind intact Descemet’s membrane & endothelium – immunologic barrier to rejection.

  35. Keratoplasty : Optical

    • It is the corneal transplant procedure done to improve visual acuity.

  36. Keratoplasty : Penetrating

    • It is the corneal transplant procedure in which full thickness diseased host corneal tissue is excised & replaced with healthy donor cornea.

  37. Keratoplasty : Tectonic / Reconstructive

    • It is the corneal transplant procedure done to restore altered corneal structure.

  38. Keratoplasty : Therapeutic

    • It is the corneal transplant procedure done in infectious keratitis to eliminate infectious load in eyes with keratitis unresponsive to specific antimicrobial therapy.

  39. Megalocornea

    • It is the enlarged cornea not secondary to glaucoma measuring more than 13 mm in horizontal diameter. If ciliary ring & lens also enlarged it is termed as megalopthalmos.

  40. Microcornea

    • It is the cornea with horizontal diameter less than 11 mm.

  41. Microphthalmos

    • It is the small eye malformed in other ways.

  42. Nanophthalmos

    • It is the condition in which eye is small but otherwise normal.

  43. Ocular Hypertension

    • It is the condition with elevated intra ocular pressure with normal optic nerve, normal visual field & no known ocular or systemic condition accounting for increased intra ocular pressure.

  44. Optic Neuritis

    • It is involvement of any part of the optic nerve by a disease process that impairs nerve conduction as indicated by loss of visual acuity & visual field changes.

  45. Panophthalmitis

    • It is the inflammation involving entire globe often with orbital extension.

  46. Papilla

    • It is reddish flat topped raised areas with central core of numerous dilated blood vessels surrounded by lymphocytes & covered by hypertrophic epithelium.

  47. Papilloedema

    • It is purely hydrostatic, non-inflammatory edema of the optic nerve head or disc due to increased intra cranial pressure.

  48. Photophobia

    • It is discomfort experienced on exposure to bright light.

  49. Phthisis bulbi

    • In final stage end result of any form of chronic uveitis, disorganisation of ciliary body hampers aqueous production resulting into soft small shrinked atrophic globe known as phthisis bulbi.

  50. Pingecula

    • It is an  elastotic degeneration of collagen fibres of the substantia propria of conjunctiva with deposition of hyaline material in the substance of conjunctiva.

  51. Primary Angle Closure

    • It is the condition characterised by > 270° of irido trabecular contact with either elevated intra ocular pressure and/or PAS ( Peripheral Anterior Synechia ) with normal optic disc & visual field examination.

  52. Pterygium

    • It is the degenerative, hypreplastic condition of the conjunctiva where sub conjunjunctival tissue undergoes elastotic degeneration & proliferates as vascularised granulation tissue under the epithelium which ultimately encroaches the cornea from the other side within the inter palpebral fissure, destroying corneal epithelium, Bowman’s & superficial stroma.

  53. Ptosis / Blepharoptosis

    • It is the condition in which there is abnormally low position of the upper lid, congenital or acquired.

  54. RD : Exudative / Serous / Solid / Secondary

    • It is the condition in which neither a break nor traction , but sub retinal fluid is derived from fluid in the vessels of the neuro sensory retina or choroid or both.

  55. RD : Rhegmatogenous / Simple / Primary

    • It occurs secondary to a full thickness defect in the sensory retina, which permits fluid derived from synchitic ( liquified ) vitreous to gain access to the sub retinal space.

  56. RD : Tractional

    • It is the condition in which neuro sensory retina is pulled away from the retinal pigment epithelium by contracting vitreo retinal membrane in the absence of a retinal break.

  57. Refraction

    • It is the method of evaluating the optical state of the eye.

  58. Retinal Break

    • It is the full thickness defect in the neuro sensory retina connecting vitreous cavity & subretinal space between neuro sensory retina & retinal pigment epithelium.

  59. Retinal detachment

    • The separation of neuro sensory retina from retinal pigment epithlium caused by a breakdown of the forces that attach them.

  60. Retinal Hole

    • It is an opening, often round in which there is no attached flap of retina, caused by chronic atrophy / focal disintegration & dis appearance of retinal tissue or because of piece of retina has been pulled away from the rest of the retina. Most common site : Supero- Temporal.

  61. Retinal Tear

    • It is the break ripped open by traction mostly dynamic vitreo-retinal, but rarely from a zonule.

  62. Retinopathy of Prematurity

    • It is a proliferative retinopathy affecting premature infants ( < 34 weeks of gestation ) of very low birth weight ( < 1500 gms ) who have been exposed to high ambient oxygen concentration.

  63. Second sight

    • In nuclear sclerosis,  due to progressive index myopia, distant vision deteriorates & near vision improves; so patients can read without presbyopic glasses. This condition is known as “second sight”.

  64. Subluxation

    • It is partial displacement in which lens is moved sideways ( up, down, medial or lateral ) but remains behind the pupil. It results from partial rupture or unequal stretching of the zonules.

  65. Synergist

    • They are the muscles of the same eye that move the eye in the same direction to the agonist.

  66. Vergence

    • It is binocular, simultaneous, synchronous, symmetric & disjugate or disjunctive movements of the eyes in opposite direction.

  67. Visual Acuity

    • It is the measurement of the threshold of discrimination of two spatially separated targets.

  68. Vitreo Retinal Traction

    • It is the force exerted on the retina by structures originating in the vitreous.

  69. Yoke muscle / Contralateral synergist

    • The pair of muscles one in each eye that produce conjugate ocular movements.