Amund Ringvold

• Ringvold, Amund (2024). Pecten oculi – et omdiskutert organ i fugleøyet . Naturen. ISSN 0028-0887. doi: 10.18261/naturen.148.2.6.
• Ringvold, Amund (2023). The Pecten Oculi: An Enigma in Comparative Ophthalmology. European Journal of Applied Sciences. ISSN 2634-9221. 11(6), p. 81–88. doi: 10.14738/aivp.116.15518. Show summary

  Purpose: To summarize and evaluate the latest hypotheses on the function of the pecten oculi (PO). Methods: Review of relevant literature. Results: The PO is an organ present in all avian eyes. A similar structure, the conus papillaris (CP), is also found in terrestrial reptiles. Several reports have claimed the PO nourishes the avascular avian retina, but it has also been argued that the function is not primarily nutritive but instead may be related to intraocular pH-regulation, as the avian retina has an anaerobic metabolism. These conclusions are, at first glance, contradictory. However, a recent report indicated how these two views may be incorporated in a new and unifying hypothesis, with the common denominator being that the CP/PO evolved in tandem with increasing uric acid (UA) in serum. Discussion: According to Wingstrand and Munk, the PO leaks oxygen and nutrients to the retina, meaning that leakage of the small and heavily soluble component UA in serum could follow the same path. Protein-binding of the UA is not an option in the vitreous body, as the UA could crystalize intraocularly and harm the visual function. Two mechanisms countering this situation have been identified: 1) The inflow of the UA to the intraocular compartments (i. e. - vitreous body and anterior chamber) is reduced through selective barriers both in the PO and in the ciliary body. 2) The UA solubility is increased through alkalization of the vitreous body by the PO. Conclusion: During evolution vision was improved when the retinal vessels were collected in the PO. Two competing hypotheses on the PO’s function have been summarized, and it is shown how these may be incorporated in a new unifying hypothesis.

• Slettedal, Jon Klokk; Traustadóttir, Valgerður Dóra; Sandvik, Leiv & Ringvold, Amund (2023). Relationship Between the Prevalence of Glaucoma (Estimated Through Prescribed Antiglaucomatous Medication) And Access to Ophthalmologists in Norway. Open Ophthalmology Journal. ISSN 1874-3641. 17. doi: 10.2174/18743641-v16-e221226-2022-20.
• Lucas, Agustín Nicolás; Copati, Irene; Sivori, Delia & Ringvold, Amund (2021). Pseudoexfoliation syndrome in a 27-year-old patient: a case report. Arquivos Brasileiros de Oftalmologia. ISSN 0004-2749. 84(3), p. 275–278. doi: 10.5935/0004-2749.20210041.
• Slettedal, Jon Klokk; Sandvik, Leiv & Ringvold, Amund (2021). Significant lifespan difference between primary open-angle glaucoma and pseudoexfoliation glaucoma. Heliyon. ISSN 2405-8440. 7(3). doi: 10.1016/j.heliyon.2021.e06421. Full text in Research Archive
• Zawadzka, Malgorzata Elzbieta; Racz, Beatrix; Ambrosini, Dario; Görbitz, Carl Henrik; Morth, Jens Preben & Wilkins, Alistair L. [Show all 12 contributors for this article] (2021). Searching for a UV-filter in the eyes of high-flying birds. Scientific Reports. ISSN 2045-2322. 11(1). doi: 10.1038/s41598-020-79533-2. Full text in Research Archive
• Slettedal, Jon Klokk; Traustadottir, Valgerdur Dora; Sandvik, Leiv & Ringvold, Amund (2020). The prevalence and incidence of glaucoma in Norway 2004–2018: A nationwide population-based study. PLOS ONE. ISSN 1932-6203. 15(12). doi: 10.1371/journal.pone.0242786. Full text in Research Archive
• Lorenzo, Yolanda; Haug, Kristiane; Ringvold, Amund; Petrovski, Goran; Moe, Morten Carsten & Collins, Andrew Richard [Show all 7 contributors for this article] (2018). Levels of oxidative DNA damage are low in ex vivo engineered human limbal epithelial tissue. Acta Ophthalmologica. ISSN 1755-375X. 96(8), p. 1–7. doi: 10.1111/aos.13811. Full text in Research Archive
• Slettedal, Jon Klokk; Sandvik, Leiv & Ringvold, Amund (2018). Lifespan reduction due to neoplasia is nullified by pseudoexfoliation syndrome. Heliyon. ISSN 2405-8440. 4(10). doi: 10.1016/j.heliyon.2018.e00832. Full text in Research Archive
• Ringvold, Amund (2018). Øyesten. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 138(6), p. 1–3. doi: 10.4045/tidsskr.17.0976.
• Konstas, A.G.P. & Ringvold, Amund (2018). Epidemiology of Exfoliation Syndrome. Journal of glaucoma. ISSN 1057-0829. 27, p. S4–S11. doi: 10.1097/IJG.0000000000000908.
• Ringvold, Amund & Reubsaet, Leon (2016). The impact of high-dose acetylcholine on bovine corneal epithelium. Acta Ophthalmologica. ISSN 1755-375X. 94(2), p. 160–164. doi: 10.1111/aos.12889.
• Slettedal, Jon Klokk; Sandvik, Leiv & Ringvold, Amund (2015). Ocular pseudoexfoliation syndrome and life span. EBioMedicine. ISSN 2352-3964. 2(7), p. 765–769. doi: 10.1016/j.ebiom.2015.05.024.
• Slettedal, Jon Klokk & Ringvold, Amund (2015). Correlation between corneal and ambient temperature with particular focus on polar conditions. Acta Ophthalmologica. ISSN 1755-375X. 93(5), p. 422–426. doi: 10.1111/aos.12657.
• Lorenzo, Yolanda; Haug, Kristiane; Ustgaard-Andersen, Kristine; Johnsen, Erik Otter; Ringvold, Amund & Moe, Morten Carsten [Show all 10 contributors for this article] (2013). Trypsin for Dissociation of Limbal Cells for Engineering of Grafts May Induce DNA Strand Breaks in the Harvested Cells. Journal of Ocular Biology. ISSN 2334-2838. 11, p. 1–6.
• Drolsum, Liv; Ringvold, Amund & Nicolaissen, Bjørn (2007). Cataract and glaucoma surgery in pseudoexfoliation syndrome: a review. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 85(8), p. 810–21.
• Ringvold, Amund Daniel & Reubsaet, Jan Leo (2005). Acetylcholine in the corneal epithelium of diurnal and nocturnal mammals. Cornea. ISSN 0277-3740. 24(8), p. 1000–1003.
• Reubsaet, Jan Leo & Ringvold, Amund Daniel (2005). Identification of Unknown Quatenary Ammonium Compounds in Corneal Epithelium and Aqueous Humor. Journal of Chromatographic Science. ISSN 0021-9665. 43(8), p. 401–405.
• Bjerkås, Ellen; Holst, Jens Christian; Bjerkås, Inge & Ringvold, Amund (2003). Osmotic cataract causes reduced vision in wild Atlantic salmon postsmolts. Diseases of Aquatic Organisms. ISSN 0177-5103. 55, p. 151–159.
• Ringvold, Amund; Anderssen, Erlend; Jellum, Egil; Bjerkås, Ellen; Sonerud, Geir & Haaland, Peder [Show all 8 contributors for this article] (2003). UV-absorbing compounds in the aqueous humor from aquatic mammals and various non-mammalian vertebrates. Ophthalmic Research. ISSN 0030-3747. 35, p. 208–216. doi: 10.1159/000071172.
• Ringvold, Amund Daniel; Andersen, Erling & Kjøniksen, Inge (2003). Impact of the enviroment on the mammalian corneal epithelium. Investigative Ophthalmology and Visual Science. ISSN 0146-0404. 44, p. 10–15.
• Stojanovic, A.; Ringvold, Amund Daniel & Nitter, T. (2003). Ascorbate prophylaxis for corneal haze after photorefractive keratectomy. Journal of cataract and refractive surgery. ISSN 0886-3350. 19, p. 338–343.
• Reubsaet, Jan Leo; Ahlsen, E; Haneborg, K G & Ringvold, Amund Daniel (2003). Sample preparation and determination of acetylcholine in corneal epithelium cells using liquid chromatography-tandem MS. Journal of Chromatographic Science. ISSN 0021-9665. 41(3), p. 151–156.
• Kjønniksen, Inge; Bjerkås, Ellen; Jellum, Egil & Ringvold, Amund (2002). Comparison of free amino acids in aqueous humor of farmed and wild salmon and of six species additionally. Ophthalmic Research. ISSN 0030-3747. 34(6), p. 366–370.
• Koliakos, G.G.; Konstas, A.G.P.; Schlötzer-Schrehart, U.; Bufidis, T.; Georgiadis, N. & Ringvold, Amund Daniel (2002). Ascorbic acid concentration is reduced in the aqueous humor of patients with exfoliation syndrome. American Journal of Ophthalmology. ISSN 0002-9394. 134, p. 879–883.
• Ringvold, Amund Daniel (2001). Rikshospitalets Øyeavdeling gjennom de siste 25 år. In Johansen, O. & Hultgren, J.S. (Ed.), 75 år i øyefagets tjeneste. Norsk Oftalmologisk Forening 1926 - 2001. Norsk Oftalmologisk Forening. p. 120–123.
• Ringvold, Amund Daniel; Anderssen, Erlend & Kjøniksen, Inge (2000). Distribution of Ascorbate in the Anterior Bovine Eye. Investigative Ophthalmology and Visual Science. ISSN 0146-0404. 41, p. 20–23. Show summary

  Distribution of Ascorbate in the Anterior Bovine Eye

• Ringvold, Amund Daniel; Anderssen, Erlend & Kjøniksen, Inge (2000). UV absorption by uric acid in diurnal bird aqueous humor. Investigative Ophthalmology and Visual Science. ISSN 0146-0404. 41, p. 2067–2069.
• Ringvold, Amund Daniel (1999). Bilateral open-angle glaucoma. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 77, p. 114–116.
• Ringvold, Amund Daniel (1999). Epidemiology of the pseudoexfoliation syndrome. A review. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 77, p. 371–375.
• Knagenhjelm, S. K. H.; Frøyland, K.; Ringvold, Amund Daniel; Bjerkås, Ellen & Kjøniksen, Inge (1999). Toxicological evaluation of cyclosporine eyedrops. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 77, p. 200–203.
• Ringvold, Amund Daniel (1998). Corneal epithelium and UV-protection of the eye. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 76, p. 149–153.
• Ringvold, Amund Daniel (1998). Ascorbate as UV-prophylaxis in excimer laser surgery. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 76, p. 755–755.
• Ringvold, Amund Daniel; Anderssen, Erlend & Kjøniksen, Inge (1998). Ascorbate in the Corneal Epithelium of Diurnal and Nocturnal Species. Investigative Ophthalmology and Visual Science. ISSN 0146-0404. 39, p. 2774–2777.
• Ringvold, Amund Daniel; Blika, Sigmund & Sandvik, Leiv (1997). Pseudo-exfoliation and mortality. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 75, p. 255–256.
• Ringvold, Amund Daniel (1997). In vitro evidence for UV-protection of the eye by the corneal epithelium mediated by the cytoplasmic protein, RNA, and ascorbate. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 75, p. 496–498.
• Ringvold, Amund Daniel (1997). Uveoscleral drainage route. Letter to the editor. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 75, p. 477–477.
• Ringvold, Amund Daniel (1996). The significance of ascorbate in the aqueous humour protection against UV-A and UV-B. Experimental Eye Research. ISSN 0014-4835. 62, p. 261–264.
• Ringvold, Amund (1996). Epidemiology of glaucoma in northern Europe. . European Journal of Ophthalmology. ISSN 1120-6721. 6(1), p. 26–29.
• Dimitrakoulias, N; Konstas, AG; Ringvold, Amund; Stefaniotou, M & Tarkkanen, A. (1995). Exfoliation glaucoma. Ophthalmologica. ISSN 0030-3755. 7, p. 329–339.
• Halvorsen, Frode; Nicolaissen, Bjørn; Ringvold, Amund & Nass, O (1995). In vitro studies of conjunctival cells from eyes with and without pseudoexfoliation. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 73(1), p. 37–40.
• Ringvold, Amund & Øvergaard, Ralf Gunnar (1995). Increased IgA antibodies to gluten and gliadin in serum of persons with ocular pseudo-exfoliation. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 73(2), p. 171–172.
• Ringvold, Amund (1995). Quenching of UV-induced fluorescence by ascorbic acid in the aqueous humour. Acta Ophthalmologica Scandinavica. ISSN 1395-3907. 73(6), p. 529–533.
• Ringvold, Amund (1994). Exfoliation glaucoma. Ophthalmologica. ISSN 0030-3755. 6, p. 403–409.
• Ringvold, Amund (1994). Corneal endothelial involvement in pseudoexfoliation syndrome. Archives of ophthalmology. ISSN 0003-9950. 112(3), p. 297–298.
• Ringvold, Amund (1993). Update on etiology and pathogenesis of the pseudoexfoliation syndrome. New Trends in Ophthalmology. ISSN 0394-3755. 8, p. 177–180.
• Ringvold, Amund (1993). How to judge the efficacy of glaucoma treatment. Acta Ophthalmologica. ISSN 1755-375X. 71(4), p. 573–573.
• Lippa, EA; Carlson, LE; Ehinger, B.; Eriksson, LO; Finnström, K & Holmin, C [Show all 15 contributors for this article] (1992). Dose Response and Duration of Action of Dorzolamide, a Topical Carbonic Anhydrase Inhibitor. Archives of ophthalmology. ISSN 0003-9950. 110(4), p. 495–499.
• Fiskaadal, HJ; Nicolaissen, Bjørn; Ringvold, Amund & Naess, O (1992). In vitro ingrowth of choroidal cells on Bruch's membrane. Acta Ophthalmologica. ISSN 1755-375X. 70(3), p. 297–302.
• Nicolaissen, Bjørn; Ringvold, Amund & Naess, O (1992). Amino acid incorporation in cell cultures from eyes with pseudo-exfoliation material. Acta Ophthalmologica. ISSN 1755-375X. 70(3), p. 371–375.
• Davanger, Martin & Ringvold, Amund (1992). The cumulative frequency distribution curve of the eye pressure. Acta Ophthalmologica. ISSN 1755-375X. 70(4), p. 489–494.
• Ringvold, Amund; Sagen, Erling; Bjerve, Kristian S & Følling, Ivar (1991). Increased Magnesium in aquous humour from patients with senile cataract. Acta Ophthalmologica. ISSN 1755-375X. 69, p. 540–543.
• Ringvold, Amund; Blika, Sigmund; Elsås, Tor B.; Guldahl, J; Brevik, T & Hesstvedt, P [Show all 10 contributors for this article] (1991). The middle-Norway eye-screening study. II. Prevalence of simple and capsular glaucoma. Acta Ophthalmologica. ISSN 1755-375X. 69(3), p. 273–280.
• Ringvold, Amund & Davanger, Martin (1991). Electrondense cell inclusions of the human cone inner segments. Acta Ophthalmologica. ISSN 1755-375X. 69(4), p. 491–495.
• Davanger, Martin; Ringvold, Amund; Blika, Sigmund & Elsås, Tor B. (1991). Frequency distribution of IOP. Analysis of a material using the gamma distribution. Acta Ophthalmologica. ISSN 1755-375X. 69(5), p. 561–564.

View all works in Cristin

• Ringvold, Amund; Juel, Erik & Blika, Sigmund (1993). High prevalence of Kell positive blood group in the Hitra population. Tapir Akademisk Forlag. ISBN 9788251914581. 11 p.

View all works in Cristin

• Racz, Beatrix; Zawadzka, Malgorzata Elzbieta; Skytte Af Sätra, Jenny Marie; Ringvold, Amund; Rise, Frode & Lundanes, Elsa [Show all 7 contributors for this article] (2018). Identification of “compound X” in goose aqueous humour.
• Ringvold, Amund (2017). Martin Davanger. En biografisk skisse 1927-1994. Oftalmologi. p. 20–22.
• Hørven, Ivar; Ringvold, Amund & Syrdalen, Per (2008). Nekrolog. Tor Flage. Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116.
• Ringvold, Amund (2007). Minneord - Håkon Leira. In Espmark, Yngve & Sæther, Bjørn (Ed.), Det Kongelige Norske Videnskabers Selskab Årbok 2006. Det Kongelige Norske Videnskabers Selskab. ISSN 82-471-6044-7. p. 173–176.
• Ringvold, Amund (2007). Welding without the Use of Eye Protective Equipment. See videolink online. Cornea. ISSN 0277-3740. 26.
• Ringvold, Amund (2005). Epidermiology of the exfoliation syndrome and exfoliative glaucoma. EU-exfoliative booklet.
• Ringvold, Amund Daniel (2004). UV-induserte skader og beskyttelsesmekanismer i fremre segment.
• Reubsaet, Jan Leo; Ahlsen, E; Haneborg, K.G. & Ringvold, Amund Daniel (2004). Sample preparation and determination of acetylcholine in corneal epithelium cells using LC-MS/MS.
• Reubsaet, Jan Leo; Ahlsen, E; Haneborg, K.G. & Ringvold, Amund Daniel (2004). Sample preparation and determination of acetylcholine in corneal epithelium cells using LC-MS/MS.
• Ringvold, Amund Daniel (2003). Destillert oftalmologi. Tidsskrift for Den norske legeforening. ISSN 0029-2001.
• Ringvold, Amund Daniel (2002). Øyeskader fremkalt av UV-stråling.
• Haaskjold, Erling & Ringvold, Amund (2002). Nekrolog. Asbjørn Martin Tønjum. Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116.
• Ringvold, Amund Daniel (2001). Snøblindhet.
• Ringvold, Amund Daniel (2001). Pseudoexfoliation and aortic aneurysms. The Lancet. ISSN 0140-6736. 357, p. 2139–2140.
• Ringvold, Amund Daniel (2001). Eye know how. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 121, p. 2093–2093.
• Ringvold, Amund Daniel (2001). Norske medisinstudenter i utlandet. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 121, p. 2093–2093.
• Ringvold, Amund Daniel (2001). Exfoliation Syndrome - A Major Cause Of Blindness: The Third International Lindberg Society Symposium on Exfoliation Syndrome.
• Stojanovic, A.; Ringvold, Amund Daniel & Nitter, T. (2001). Ascorbate Prophylaxis for Corneal Haze After PRK.
• Ringvold, Amund Daniel (2001). Exfoliation syndrome as a global problem.
• Ringvold, Amund Daniel (2000). Pigment dispersion and capsular glaucoma. Eye (London. 1987). ISSN 0950-222X. 14, p. 410–410.
• Ringvold, Amund Daniel (1999). Øyerelaterte kapitler, Store Norske leksikon. Gyldendalske bokhandel, Nordisk forlag A/S.
• Ringvold, Amund Daniel (1999). Hvorfor blir vi snøblinde? Nysjerrigper. p. 14–14.
• Ringvold, Amund Daniel (1999). Solformørkelse. [Radio]. Dagsrevyen : NRK.
• Ringvold, Amund Daniel (1999). Øyeskader ved ultrafiolett bestråling. [Radio]. Radio.
• Ringvold, Amund Daniel (1999). Solformørkelse. [Radio]. Radio.
• Ringvold, Amund Daniel (1999). Etiology of the pseudoexfoliation syndrome.
• Ringvold, Amund Daniel (1999). Øyeskader etter solformørkelse.
• Ringvold, Amund Daniel (1999). Epidemiology of the pseydoexfoliation syndrome.
• Ringvold, Amund Daniel; Andersen, Erling & Kjøniksen, Inge (1998). Forekomst av vitamin C i corneaepitelet hos dag- og nattdyr.
• Hørven, Ivar & Ringvold, Amund Daniel (1997). Nekrolog. Thore Lie Thomassen. Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116.
• Ringvold, Amund Daniel (1997). Operasjon eller briller. Bokanmeldelse. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 117, p. 187–187.
• Ringvold, Amund Daniel (1997). Retinas anatomi og fysiologi.
• Ringvold, Amund (1997). Øyerelaerte emner. In Henriksen, P. (Eds.), Aschehoug og Gyldeldals Store norske leksikon. Kunnskapsforlaget. ISSN 82-573-0684-3.
• Ringvold, Amund Daniel (1996). Glaukomdiagnose og behandling.
• Ringvold, Amund Daniel (1996). Okulær traumatologi.
• Ringvold, Amund Daniel (1996). Øyeblikkelig hjelp i oftalmologien.
• Ringvold, Amund Daniel (1996). Visus. Refraksjon.
• Hørven, Ivar & Ringvold, Amund (1994). Nekrolog. Martin Davanger. Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116.
• Ringvold, Amund (1994). Blindness-problems of Norwegian patients seen in a global perspective. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 114(25), p. 2935–2936.
• Ringvold, Amund (1993). Nærsyntkirurgi. Optikeren. ISSN 0333-1598. 3, p. 48–49.
• Ringvold, Amund (1993). Surgery for myopia. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 113(1), p. 14–15.
• Ringvold, Amund (1993). Acute eye problems. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 113(16), p. 1997–2000.
• Ringvold, Amund (1992). Ozonhuller og eventuelle konsekvenser. Oftalmolog. ISSN 0108-5344. 12, p. 11–12.
• Ringvold, Amund; Blika, S; Elsås, Tor B.; Guldahl, J; Juel, E & Brevik, T [Show all 11 contributors for this article] (1992). The middle-Norway eye-screening study. III. The prevalence of capsular glaucoma is influenced by blood-group antigens. Acta Ophthalmologica. ISSN 1755-375X. 70(2), p. 207–213.

View all works in Cristin