Ocular hypotony, or ocular hypotension, or shortly hypotony, is the medical condition in which intraocular pressure (IOP) of the eye is very low.
Description[edit]
Normal IOP ranges between 10–20 mm Hg.[1] The eye is considered hypotonous if the IOP is ≤5 mm Hg (some sources say IOP less than 6.5 mmHg).[2][3]
Types[edit]
Ocular hypotony is divided into statistical and clinical types. If intraocular pressure is low (less than 6.5 mm Hg) it is called statistical hypotony, and if the reduced IOP causes a decrease in vision, it is called clinical.[4]
Causes[edit]
Hypotony may occur either due to decreased production of aqueous humor or due to increased outflow. Hypotony has many causes including post-surgical wound leak from the eye, chronic inflammation within the eye including iridocyclitis, hypoperfusion, tractional ciliary body detachment or retinal detachment.[5] Eye inflammation, medications including anti glaucoma drugs, or proliferative vitreoretinopathy causes decreased production.[6] Increased outflow or aqueous loss may occur following a glaucoma surgery, trauma, cyclodialysis cleft or retinal detachment.[6]
Complications[edit]
Decreased IOP may lead to phthisis bulbi.[3] Hypotony maculopathy is another complication caused by very low IOP.[7]
Treatment[edit]
Treatment of hypotony is depending on the cause of the condition.[6] Chronic ocular hypotony may be treated with intraocular injection of sodium hyaluronate.[8] If the cause of hypotony is an over filtering bleb, cycloplegia using atropine may be used.[2]
References[edit]
- ^ "Eye Pressure". American Academy of Ophthalmology. 19 January 2018.
- ^ a b N.Y, Valerie Trubnik, MD, FACS, Mineola. "Managing Hypotony After Trabeculectomy". www.reviewofophthalmology.com.
{{cite web}}: CS1 maint: multiple names: authors list (link) - ^ a b Schmack, Ingo; Völcker, Hans E; Grossniklaus, Hans E (1 January 2010). "Chapter 54 - Phthisis bulbi". Ocular Disease. W.B. Saunders. pp. 415–423. ISBN 978-0-7020-2983-7.
- ^ Thomas, Merina; Vajaranant, Thasarat S.; Aref, Ahmad A. (December 2015). "Hypotony Maculopathy: Clinical Presentation and Therapeutic Methods". Ophthalmology and Therapy. 4 (2): 79–88. doi:10.1007/s40123-015-0037-z. ISSN 2193-8245. PMC 4675727. PMID 26253854.
- ^ "Ocular Hypotony: Background, Pathophysiology, Epidemiology". 19 July 2021.
- ^ a b c Fine, Howard F.; Biscette, O'neil; Chang, Stanley; Schiff, William M. (January 2007). "Ocular hypotony: a review". Comprehensive Ophthalmology Update. 8 (1): 29–37. ISSN 1527-7313. PMID 17394757.
- ^ "Hypotony Maculopathy - EyeWiki". eyewiki.aao.org.
- ^ Küçükerdönmez, C.; Beutel, J.; Bartz-Schmidt, K. U.; Gelisken, F. (1 February 2009). "Treatment of chronic ocular hypotony with intraocular application of sodium hyaluronate". British Journal of Ophthalmology. 93 (2): 235–239. doi:10.1136/bjo.2008.143834. ISSN 0007-1161. PMID 18829633. S2CID 36520175.