History

The history of low-tension glaucoma (LTG) may include the following:

Ocular history
Steroid use
Trauma
Vasospasm (see below)
- Raynaud syndrome
- Migraine headaches
Coagulopathies - Previous blood loss or shocklike episode
Systemic nocturnal hypotension (notably in older thin, white women)
Autoimmune disorders (evidence of other autoimmune diseases common)
Systemic vascular disease
Thyroid disease - Increased incidence of thyroid disease in patients with low-tension glaucoma (6 of 25 patients in 1 series)
Sleep apnea (particularly in heavy men)
Alzheimer disease - Associated with mild increase in cup-to-disc ratio
Family history of glaucoma or optic neuropathy

Physical

Physical examination findings in low-tension glaucoma (LTG) may include the following:

Conduct general medical examination (eg, blood pressure, carotid arteries).
Exclude ocular hypertension and POAG
Refractive error - Myopia
Cornea (see below)
- Central corneal thickness thinner in normal-tension glaucoma^[3]in correlation with severity
- Keratic precipitates indicating uveitis
- Krukenberg spindle indicating pigment dispersion
Iris - Transillumination defects or pigment dusting indicating pigment dispersion
Anterior chamber (see below)
- By definition, low-tension glaucoma has an open, normal-appearing angle.
- Rule out angle closure and angle recession.
Lens - Glaucomflecken indicating previous IOP elevation, probably secondary to acute angle closure
Posterior synechiae
Peripheral anterior synechiae
Intraocular pressure (see below)
- Perform diurnal curve (should be < 22 mm Hg).
- May be asymmetric
- Higher IOP in left eye (related to blood flow from carotid arteries)
  - IOP fluctuation leads to greater visual-field progression in normal-tension glaucoma^[3]
  - Other - Corneal compensated IOP using the Ocular Response Analyzer^[4]
Myopic - Greatest risk of progression
Senile sclerotic - Older with vascular disease
Focal ischemic - May be younger
Optic disc in low-tension glaucoma as compared to high-tension glaucoma (controversial)
Larger discs
Peripapillary disc atrophy (particularly beta zone)
Thin disc rims; more commonly shows notching, more sloping of cup
Narrow vessels in peripapillary area, independent of stage of the disease^[5]
Disc hemorrhages^[6]
Acquired pit
Retina - Arteriosclerotic changes indicating vascular disease
Visual fields in low-tension glaucoma as compared to high-tension glaucoma (controversial)
Focal
Closer to fixation
Deeper
Blood pressure - Nocturnal hypotension
Carotid bruit indicating carotid insufficiency

Causes

Low-tension glaucoma is associated with the following:

Migraine
Peripheral vasospasm, Raynaud syndrome
Generalized peripheral vascular endothelial dysfunction^[7]
Ocular circulation insufficiency (lower ocular pulse amplitude)^[7]
Increased resistance index in the central retinal artery (role in progression of visual field defect)^[8]
Impaired vascular autoregulation (prolonged arteriovenous venous passage time in relation to ocular perfusion)^[9]
Autoimmune disorders
Systemic vascular disease (ie, atherosclerotic disease, cerebrovascular insufficiency)^[10]
Systemic nocturnal hypotension
Sleep apnea (decreases oxygen saturation)

Complications

Permanent loss of vision can occur if low-tension glaucoma is not detected early.

Differential Diagnoses

Kim M, Kim TW, Park KH, Kim JM. Risk factors for primary open-angle glaucoma in South Korea: the Namil study. Jpn J Ophthalmol. 2012 Jul. 56(4):324-9. [QxMD MEDLINE Link].
Kim KCY, Ahn AMD, Seong SGJ. Does redefining of high intraocular pressure (IOP) according to IOP distribution change prevalence of normal tension glaucoma in Korea? [abstract]. World Glaucoma Congress, 2009. Available at http://www.worldglaucoma.org/WGC/WGC2009/index.php. Accessed: July 24, 2009.
Caprioli J, Coleman AL. Intraocular pressure fluctuation a risk factor for visual field progression at low intraocular pressures in the advanced glaucoma intervention study. Ophthalmology. 2008 Jul. 115(7):1123-1129.e3. [QxMD MEDLINE Link].
Paul T, Radcliffe N, Shimmio M. Reclassification of normal and high tension glaucoma eyes using corneal compensated IOP [abstract]. World Glaucoma Congress, 2009. Available at http://www.worldglaucoma.org/WGC2009/. Accessed: July 28, 2009.
Akopov E, Astakhov Y, Nefedova D. Retinal vessels calibrometry in normal pressure glaucoma evaluation [abstract]. World Glaucoma Congress, 2009. Available at http://www.worldglaucoma.org/WGC/WGC2009/index.php. Accessed: July 28, 2009.
Furlanetto RL, De Moraes CG, Teng CC, Liebmann JM, Greenfield DS, Gardiner SK, et al. Risk factors for optic disc hemorrhage in the low-pressure glaucoma treatment study. Am J Ophthalmol. 2014 May. 157(5):945-52. [QxMD MEDLINE Link].
Su WW, Cheng ST, Hsu TS, Ho WJ. Abnormal flow-mediated vasodilation in normal-tension glaucoma using a noninvasive determination for peripheral endothelial dysfunction. Invest Ophthalmol Vis Sci. 2006 Aug. 47(8):3390-4. [QxMD MEDLINE Link].
Delaney Y, Walshe TE, O'Brien C. Vasospasm in glaucoma: clinical and laboratory aspects. Optom Vis Sci. 2006 Jul. 83(7):406-14. [QxMD MEDLINE Link].
Plange N, Kaup M, Remky A, Arend KO. Prolonged retinal arteriovenous passage time is correlated to ocular perfusion pressure in normal tension glaucoma. Graefes Arch Clin Exp Ophthalmol. 2008 Aug. 246(8):1147-52. [QxMD MEDLINE Link].
Harris A, Siesky B, Zarfati D, et al. Relationship of cerebral blood flow and central visual function in primary open-angle glaucoma. J Glaucoma. 2007 Jan. 16(1):159-63. [QxMD MEDLINE Link].
Chauhan BC, Mikelberg FS, Balaszi AG, LeBlanc RP, Lesk MR, Trope GE. Canadian Glaucoma Study: 2. risk factors for the progression of open-angle glaucoma. Arch Ophthalmol. 2008 Aug. 126(8):1030-6. [QxMD MEDLINE Link]. [Full Text].
Zhang YQ, Li J, Xu L, Zhang L, Wang ZC, Yang H, et al. Anterior visual pathway assessment by magnetic resonance imaging in normal-pressure glaucoma. Acta Ophthalmol. 2012 Jun. 90(4):e295-302. [QxMD MEDLINE Link].
Asano E, Mochizuki K, Sawada A, Nagasaka E, Kondo Y, Yamamoto T. Decreased nasal-temporal asymmetry of the second-order kernel response of multifocal electroretinograms in eyes with normal-tension glaucoma. Jpn J Ophthalmol. 2007 Sep-Oct. 51(5):379-89. [QxMD MEDLINE Link].
Michelson G, Waerntges S, Engelhorn T, Doerfler A. Reduced optic radiation volume measured by DTI is correlated by arterial hypertension in normal tension glaucoma [abstract]. World Glaucoma Congress, 2009. Available at http://www.worldglaucoma.org/WGC/WGC2009/index.php. Accessed: July 28,2009.
[Guideline] Screening for glaucoma: recommendation statement. US Preventive Services Task Force. National Guideline Clearinghouse. 2005 Mar.
[Guideline] Primary open-angle glaucoma. American Academy of Ophthalmology. National Guideline Clearinghouse. 2005.
[Guideline] Comprehensive adult eye and vision examination. American Optometric Association. National Guideline Clearinghouse. 2005.
Orgul S, Zawinka C, Gugleta K, Flammer J. Therapeutic strategies for normal-tension glaucoma. Ophthalmologica. 2005 Nov-Dec. 219(6):317-23. [QxMD MEDLINE Link].
Tarkkanen AH, Kivelä TT. Vascular comorbidity in patients with low-tension glaucoma. Eur J Ophthalmol. 2014 Jul 21. [QxMD MEDLINE Link].
Cheng JW, Cai JP, Wei RL. Meta-analysis of medical intervention for normal tension glaucoma. Ophthalmology. 2009 Jul. 116(7):1243-9. [QxMD MEDLINE Link].
Netland PA, Chaturvedi N, Dreyer EB. Calcium channel blockers in the management of low-tension and open-angle glaucoma. Am J Ophthalmol. 1993 May 15. 115(5):608-13. [QxMD MEDLINE Link].
Takako Nakagami, Yoshio Yamazaki, Fukuko Hayamizu. Prognostic Factors for Progression of Visual Field Damage in Patients with Normal-Tension Glaucoma. Japanese Journal of Ophthalmology. January, 2006. Volume 50, Number 1:38-42.
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Author

Mitchell V Gossman, MD Partner and Vice President, Eye Surgeons and Physicians, PA; Medical Director, Central Minnesota Surgical Center; Clinical Associate Professor, University of Minnesota Medical School

Mitchell V Gossman, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Ophthalmology, American Medical Association, American Society of Cataract and Refractive Surgery, Minnesota Medical Association, North American Neuro-Ophthalmology Society, Phi Beta Kappa

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Martin B Wax, MD Professor, Department of Ophthalmology, University of Texas Southwestern Medical School; Vice President, Research and Development, Head, Ophthalmology Discovery Research and Preclinical Sciences, Alcon Laboratories, Inc

Martin B Wax, MD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, Society for Neuroscience

Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy, Sr, MD † Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences

Hampton Roy, Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, Pan-American Association of Ophthalmology

Disclosure: Nothing to disclose.

Additional Contributors

Neil T Choplin, MD Adjunct Clinical Professor, Department of Surgery, Section of Ophthalmology, Uniformed Services University of Health Sciences

Neil T Choplin, MD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, Association for Research in Vision and Ophthalmology, California Association of Ophthalmology, San Diego County Ophthalmological Society, Society of Military Ophthalmologists

Disclosure: Nothing to disclose.

Iqbal Ike K Ahmed, MD, FRCSC Clinical Assistant Professor, Department of Ophthalmology, University of Utah

Iqbal Ike K Ahmed, MD, FRCSC is a member of the following medical societies: American Academy of Ophthalmology, American Society of Cataract and Refractive Surgery, Canadian Ophthalmological Society, Ontario Medical Association

Disclosure: Nothing to disclose.

Baseer U Khan, MD

Baseer U Khan, MD is a member of the following medical societies: Canadian Ophthalmological Society

Disclosure: Nothing to disclose.

Khalid Hasanee, MD Glaucoma and Anterior Segment Fellow, Department of Ophthalmology, University of Toronto

Khalid Hasanee, MD is a member of the following medical societies: Canadian Medical Association, Canadian Ophthalmological Society, Ontario Medical Association

Disclosure: Nothing to disclose.

Jacqueline Freudenthal, MD Co-Investigator, Ophthalmic Consultants Centre, Toronto

Jacqueline Freudenthal, MD is a member of the following medical societies: American Academy of Ophthalmology, Association for Research in Vision and Ophthalmology, Canadian Ophthalmological Society

Disclosure: Nothing to disclose.