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^ Caecum (Cecum), punctum The blind spot. (From Latin punctum spot or point and caecus blind.)
^ Calcium An element which plays a vital role in cell and nervous system functioning.
^ Canal of Schlemm = sinus venosus sclerae = scleral venous sinus Vessel in the irido corneal angle of the anterior chamber of the eye draining aqueous humor from the anterior chamber percolating through the trabecular meshwork into small openings in the Canal. The Canal then drains into the scleral venous plexus.
^ Carbon Monoxide (CO) One of two gaseous intercellular messengers produced in the body. (The other is Nitric Oxide (NO·)). Like NO·, it acts as a central nervous system neurotransmitter and modifies smooth muscle function through binding to the heme moiety of soluble guanylyl cyclase. It is produced by the action of heme oxygenases 1 and 2. This gas is also neurotoxic and generally toxic if inhaled in large quantities. It binds tightly to heme proteins in hemoglobin and mitochondrial electron transport Complex IV. It has been implicated as an epigenetic factor in Leber Hereditary Optic Neuropathy.
Simmons IG, Good PA. Carbon monoxide poisoning causes optic neuropathy. Eye 1998;12 ( Pt 5):809-14 PMID 10070515
Hwang JM, Park HW. Carbon monoxide poisoning as an epigenetic factor for Leber's hereditary optic neuropathy. Korean J Ophthalmol 1996 Dec;10(2):122-3 PMID 9055542
^ Carnitine
^ Carnosine
^ Caspase Cysteine protease which binds to "death-factor receptor"-stimulated death-effector domains on adaptor proteins, FADD/MORTI. Cascades of caspase activation together with other events triggers apoptosis or programmed cell death.
^ Cell
^ Central Retinal Artery Occlusion (CRAO)
eMedicine article Kilbourn Gordon
^ Centre surround The organisation of the retina in a receptive field.
Introduction to the Visual System By Martin J. Tovee
^ Chamber, anterior~, posterior~ The space between the cornea and the lens filled with fluid, aqueous humor, is divided into anterior and posterior chambers by the iris. Aqueous humor is produced in the posterior chamber by the ciliary processes. The fluid is drained from the anterior chamber through the sinus venosus also known as the scleral Canal of Schlemm into the scleral plexuses. Regulation of intraocular pressure occurs here.
^ Chiasma, OpticThe brain juncture where the optic nerves partially cross becoming the optic tracts.
^ Choriod Vascular layer between retina and sclera.
^ Chromosome
^ Ciliary, body,muscle, artery, nerve, processes, ganglion, part of retina
^ Ciliary neurotrophic factor, CNTF
Liu X, Clark AF, Wordinger RJ. Expression of ciliary neurotrophic factor (CNTF) and its tripartite receptor complex by cells of the human optic nerve head. Mol Vis. 2007 May 23;13:758-63. PMID 17563726
^ Circadian Relating to daily rhythms. Amongst their other connections, intrinsically photosensitive retinal ganglion cells connections to the suprachiasmatic nucleus play a role here.
Wikipedia Suprachiasmatic nucleus
Wikipedia Retinal hypothalamic tract
Georg B, Ghelli A, Giordano C, Ross-Cisneros FN, Sadun AA, Carelli V, Hannibal J, La Morgia C. Melanopsin-expressing retinal ganglion cells are resistant to cell injury, but not always. Mitochondrion. 2017 Sep;36:77-84. doi: 10.1016/j.mito.2017.04.003. Epub 2017 Apr 12. PMID: 28412540.
^ CNTF (Ciliary Neurotrophic Factor)
^ Codon The three nucleotide base unit on messenger RNA (mRNA) which codes for a specific amino acid. The anti codon found on each aminoacyl-tranfer RNA (tRNA) recognizes its mRNA codon and interacts with the protein forming ribosome attached to mRNA to add its amino acid to the protein chain. cf. Intron and Exon
^ Co-enzyme Q (Ubiquinone). Hydrophobic small yellow compound. Acts as a mobile electron carrier within the lipid centre of the inner mitochondrial membrane. Its reduced form is made by Complex I (NADH Coenzyme Q reductase), Complex II (Succinate Coenzyme Q reductase), electron transfering flavoprotein and sn-glycerophosphate dehydrogenase. The reduced form is then oxided by Complex III (Coenzyme Q- Cytochrome c Reductase) to form cytochrome c. It is available as food supplement/over the counter medication. Anecdotal reports of use in treating LHON show equivocal results.
^ Coloboma A developmental defect malformation of one or more parts of the eye.
^ Complexes of the electron transport chain of oxidative phosphorylation: Groups of protein-enzymes spanning the inner mitochondrial membrane involved in energy production. The direction of the reaction goes in order from I to V culminating in the addition of a high energy phosphate to ADP creating ATP, the cell's energy currency.
^ Complex I: NADH-Coenzyme Q Reductase Also NADH dehydrogenase, NADH Ubiquinone Oxidoreductase. One of the inner mitochondrial membrane proteins of the electron transport chain of oxidative phosphorylation. As its name suggests, this enzyme complex causes NADH to donate an electron to the hydrophobic coenzyme Q (ubiquinone,UQ) reducing it to ubiquinol(UQH2) and oxidizing NADH to NAD+. As a result, four protons (hydrogen ions) are transported to the cytosol for every two electrons given by NADH to UQ. There is a chain of steps in the electron donation starting with a molecule of flavin mononucleotide at the matrix side. Iron-sulfur groups and hydrophobic polypeptides are also involved before the ubiquinone is reduced in the lipid core of the inner membrane. Complex I is divided into three main fractions: a flavoprotein group which binds NADH, an iron protein fragment which is the likely ubiquinone binder and a hydrophobic protein which hold iron sulphur groups, the electron donors to ubiquinone. It is inhibited by rotenone, ptericidin, barbiturates, mercurials, pethidine (Demerol or meperidine) and especially its analogue, MPTP. It has greater than 40 subunits seven of which are coded by mitochondrial DNA. Products of mitochondrial genes MTND1, MTND3, and MTND4L have been localized to the hydrophobic protein. MTND2, MTND4, and MTND5 gene products probably also are here. The LHON 3460, 11778, and 14484 mutations affects MTND1, MTND4, and MTND6 genes of complex I respectively. Mutations related to Alzheimers disease, Parkinson's disease, Colonic cancer, Sudden Infant Death Syndrome are also found in gene area MTND1.
OMIM NADH dehydrogenase search
^ Complex II: Succinate-Coenzyme Q Reductase Also, succinate dehydrogenase. A Krebs Cycle enzyme in the inner mitochondrial membrane. It has four subunits: two iron sulfur (Fe-S) proteins and two other peptides all coded for by the nuclear genome alone. FAD is bound on the mitochondrial matrix side. In converting succinate to fumarate in the TCA cycle it converts bound FAD to FADH2. The FADH2 passes its electrons to Fe-S centres which reduce ubiquinone (UQ) to UQH2 in the lipid centre of the membrane. There is no proton transport across the membrane. Inhibitors are Antimycin, carboxin, myxothiazol and 2-thenoyltrifluoroacetone. Compensatory increase in complex II acivity in LHON 11778 has been described:
Yen MY, Lee HC , Liu JH, Wei YH. Compensatory elevation of complex II activity in Leber's hereditary optic neuropathy. Br J Ophthalmol, 1996; 80: 78-81. PMID: 8664239
^ Complex III: Coenzyme Q-Cytochrome c Reductase Also, cytochrome bc1 complex. A transmembrane electron transport complex of the mitochondrial inner membrane. Here reduced coenzyme Q (UQH2) passes electrons to cytochrome c, a water soluble cytochrome which acts as a mobile electron carrier to the next step in the electron transport chain. Protons are pumped across the membrame to the intermembrane space. The complex is made of core proteins I and II, cytochrome b, cytochrome c1, the Rieske iron-sulfur protein , and some smaller polypeptides. Cytochrome c1 finally transfers electrons to cytochrome c in the intermembrane space. Cytochrome b is coded for by the mitochondrial genome. A mitochondrial nucleotide pair 15257 mutation is reputedly primary for LHON. A mtDNA 15812 mutant is secondary for LHON. Other mitochondrial complex III mutations have been related to colorectal cancer and exercise intolerance.
^ Complex IV: Cytochrome c Oxidase Transfers electrons from reduced cytochrome c to oxygen (O2) to make water (H2O) and acts as a proton pump out to the intermembrane space. Made of 13 subunits, the three largest and most business like units, I, II and III, are encoded by mitochondrial DNA. These three units contain Iron (Fe) in two heme protein sites (cytochromes a and a3 ) and 2 copper (Cu) atom sites (CuA and CuB) which respectively are closely associated with the Fe in two binuclear centers. The final binuclear center effectively transports its electron to bound O2 to make water in the mitochondrial matrix. Inhibitors are cyanide, azide which bind to the ferric iron of cytochrome a3 and carbon monoxide which binds to the ferrous iron. Examples of mutations are a secondary LHON factor at nucleotide pair 7444, colon cancer, and sideroblastic anemia.
^ Complex V: ATP Synthase see ATP Synthase
^ Cone, M, S, L
^ Congenital
^ Conjunctiva
^ Consciousness
^ Contrast ~sensitivity,~acuity
^ Cornea
^ Cortex, cerebral
^ Cup, Optic See Optic Cup
^ Curcumin Principal curcuminoid of the Indian curry spice turmeric. It has antioxidant effects. It is being trialed for various eye diseases in more bioavailable delivery systems than its natural form. A trial for LHON was proposed, but not completed as of writing.
Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers G Shoba , D Joy, T Joseph, M Majeed, R Rajendran, P S Srinivas Planta Med. 1998 May;64(4):353-6. doi: 10.1055/s-2006-957450. PMID: 9619120
canine uveitis
Ganugula R, Arora M, Lepiz MA, Niu Y, Mallick BK, Pflugfelder SC, Scott EM, Kumar MNVR. Systemic anti-inflammatory therapy aided by double-headed nanoparticles in a canine model of acute intraocular inflammation. Sci Adv. 2020 Aug 26;6(35):eabb7878. doi: 10.1126/sciadv.abb7878. PMID: 32923645; PMCID: PMC7449680.
Science Mag editorial commentary on drug discovery and the pharma industry. Curcumin Will Waste Your Time By Derek Lowe 12 January, 2017.
Davis, B.M., Pahlitzsch, M., Guo, L. et al. Topical Curcumin Nanocarriers are Neuroprotective in Eye Disease. Sci Rep 8, 11066 (2018). https://doi.org/10.1038/s41598-018-29393-8 glaucoma model
^ Cytochrome c Water soluble electron transporter in the mitochondrial intermembrane space on the cytosol side of the mitochondrial inner membrane. Transports electrons from the Fe-S-cyt c1 combination of complex III to complex IV of the electron transport chain. It is a globular protein with a heme center.
^ Cytochrome P450 A large and important class of enzymes [heme-thiolate proteins] for the detoxification and elimination of drugs and toxins and regulation of endogenous hormones. Found on the cytosolic endoplasmic reticulum, they are very important in drug-drug, drug-food, and other interactions. There is a large genetic variability in the enzymes. They may be relevant in various mechanisms of gene expression. Their relevance to penetrance of optic neuropathy expression is yet to be fully explored. Reports of optic neuritis with disulfiram for treatment of alcoholism may implicate P450 enzyme systems. A CYP1B1 mutation is implicated in a form of congenital glaucoma. See:
The Worldwide Physiologist Page on cytochrome P450
Plasilova M, Stoilov I, Sarfarazi M, Kadasi L, Ferakova E, Ferak V Identification of a single ancestral CYP1B1 mutation in Slovak Gypsies (Roms) affected with primary congenital glaucoma. J Med Genet 1999 Apr;36(4):290-4 PMID 10227395
^ Cytokine A group of cell surface acting proteins involved in signaling.
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