Ophthalmology Terminology L
Lagophthalmos. Incomplete closure of the eyelids. For some people, it can occur normally and in a mild form during sleep but the persistent form can cause severe corneal dryness with multiple complications.
Lang Test. Special test that is used to test stereopsis in children.
Laser Cyclophotocoagulation. A diode laser is used to ablate ciliary body in patients with refractory glaucoma. This will help to reduce aqueous humor secretion and decrease intraocular pressure.
Laser, Diabetic Retinopathy. It is also called laser photocoagulation for diabetic retinopathy. It is either panretinal coagulation of grid laser. In panretinal coagulation, Argon laser is used to induce burn marks in the peripheral retina in order to kill ischemic parts and reduce the oxygen demands of the retina and also to decrease the release of vasoendothelial growth factors which help to create abnormal blood vessels. Grid Laser is used mainly to treat macular edema by sealing the leaking microaneurysm.
Laser Iridoplasty. Argon laser is used to shrink the peripheral part of the iris, thus pull the peripheral iris away from trabecular meshwork. This procedure is done in patients with narrow angle glaucoma due to a condition called plateau iris configuration.
Laser Peripheral Iridotomy. A hole that is made in the peripheral part of the iris with laser. The main purpose of this hole is to create a passage for aqueous humor from the posterior chamber of the eye to the anterior chamber to decrease intraocular pressure in patients with pupillary block glaucoma.
Laser Thermokeratoplasty. Type of refractive surgery that can be used to treat patients with hyperopia. Small and multiple coagualtion burns are applied to peripheral part of corneal stroma with Holmium:YAG Laser.
Laser Trabeculoplasty. It is treatment of the trabecular meshwork by laser in order to enhance the outflow of the aqueous humor from the eye. This type of procedure is used to lower the intraocular pressure in patients with glaucoma.
Lasik Eye Surgery
lattice Corneal Degeneration. Type of corneal dystrophy.It is caused by deposition of amyloid particles in the corneal stroma. It can cause blurring of vision which might require corneal transplantation.
lattice Retinal Degeneration. Type of peripheral retinal degeneration which occurs in high frequency in patients with high myopia. It is a risk factor for retinal detachment. It is characterized by atrophy in the peripheral retinal layer with liquefied overlaying vitreous gel.
Laurence Moon Syndrome. A hereditary disease that presented with retinitis pigmentosa, spastic paraplegia,hypogenitalism and mental retardation.
Lebers Congenital Amaurosis. A variant of retinitis pigmentosa. It is characterized be peripheral retinal degeneration,disc edema, bull's eye maculopathy, oculoddigital sign and poor reactive pupillary reflex.It presents with blindness at early age.
Leber Hereditary Optic Neuropathy. A hereditary cause of optic atrophy. It occurs in young adult and is transmitted through mitochondrial DNA.
Lee’s Screen. A special screen that is used in strabismus assessment to differentiate between paralytic and non-paralytic strabismus. It dissociate 2 eyes with mirror while Hess chart which is used for the same purpose will dissociate 2 eyes through red and green filters.
Lens Induced Glaucoma. High intraocular pressure which is caused by the natural lens. There are four types of it which are: Phacomorphic Glaucoma, Phacolytic Glaucoma and Phaco-antigenic Glaucoma and subluxated or dislocated lens-glaucoma.
Leukocoria. Abnormal white reflex of the retina of the child instead of red reflex.
Lid Retraction. Abnormal high position of the eyelid Margin. Normally, the margin of the upper eyelid should be 2 mm between the limbus.
Limbus. The junction between the sclera(white part of the eye) and the cornea(The transparent front part of the eye)
Low Intraocular Pressure
Low Tension Glaucoma. It is another name to Normal Pressure Glaucoma.
Lowe’s Syndrome. A hereditary disease that has renal problems and ocular manifestations.
Luxturna. New gene therapy for retinal dystrophies