Normal pressure glaucoma

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Classification according to ICD-10
H40.1 Normal pressure glaucoma
ICD-10 online (WHO version 2019)

The normal tension glaucoma (outdated: low-tension glaucoma ) is a form of glaucoma (glaucoma), in which no elevated intraocular pressure - an otherwise classical symptom of glaucoma - is present, but the intraocular pressure values in the normal range up to about 21 mmHg lie. There is also a correlation with circulatory disorders and low blood pressure ( arterial hypotension ). An increased pressure sensitivity (tension tolerance) of the patient also plays a role in the development of normal pressure glaucoma. The damage to the optic nerve is therefore not triggered by mechanical influences, but rather represents the clinical picture of vascular neuropathy , which requires interdisciplinary treatment by an ophthalmologist and internist.

meaning

Traditionally, the diagnosis of glaucoma was confirmed by measuring intraocular pressure ( tonometry ). Patients with values ​​above 21 mmHg were considered to have glaucoma or at least suspicious of glaucoma, with intraocular pressure values ​​below 20 mmHg and normal fundus findings no glaucoma diagnosis was made. In recent years it has been recognized that a physiological intraocular pressure between 11 and 21 mmHg in no way excludes the presence of glaucoma. On the contrary, it is now assumed that almost half of all glaucomas in Europe are normal pressure glaucomas. In Japan, the proportion of this variant in all glaucoma diseases is estimated to be up to 90%. Normal pressure glaucoma is four times as common as high pressure glaucoma among Americans of Japanese descent.

Since normal pressure glaucoma does not have increased intraocular pressure, so-called screening examinations, which are based solely on the level of the intraocular pressure when assessing suspected glaucoma, are unsuitable for detecting the disease. Reliable evidence must therefore be provided via the changes in the optic nerve head (papilla) that are typical for glaucoma and, in the case of advanced clinical pictures, on the basis of visual field defects, for example so-called Bjerrum scotomas , and deterioration in visual acuity .

One of the foundations of the pathophysiology of normal pressure glaucoma is a reduced pressure tolerance of the person affected. The patient's optic nerve can already suffer damage from intraocular pressure values ​​that have no consequences for others.

Risk factors

An important risk factor for normal pressure glaucoma is a general circulatory problem with what is known as vascular dysregulation , i.e. with phases of inadequate blood flow due to regulation disorders of the blood vessels. Ocular blood flow is more reduced in normal pressure glaucoma than in high pressure glaucoma. One reason for this can be low blood pressure. Especially at night - and therefore often unnoticed - those affected can experience a sharp drop in blood pressure, which leads to a lack of acid and nutrients in the sensory cells in the eye. Such a complex of symptoms predisposing to normal pressure glaucoma is called Flammer's syndrome . This is a peculiarity of the human blood vessel system, which manifests itself in numerous symptoms such as low blood pressure or cold hands and feet. Other abnormalities in patients with Flammer syndrome are tinnitus , migraines , prolonged sleep times, decreased feeling of thirst and an increased sensitivity to pain, smells and a number of medications.

The metabolic syndrome also seems to be a risk factor for normal pressure glaucoma.

Patients with sleep apnea syndrome have an increased number of normal pressure glaucomas, as phases of inadequate blood flow in the head area occur in sleep apnea. A link between normal pressure glaucoma and Alzheimer's disease, which has been widely assumed, has not been proven.

Diagnosis

In addition to tonometry, the most common examination is ophthalmoscopy , the ophthalmologist's assessment of the fundus. In the case of manifest normal pressure glaucoma, typical glaucoma damage can be found, such as the indentation (excavation) of the optic nerve head (papilla) and the thinning of the edge of the papilla, although usually less pronounced than in high pressure glaucoma. Typical for normal pressure glaucoma are also small, splash-like bleeding, the bleeding at the edge of the papilla. Perimetry is used to identify any visual field losses that have already occurred .

However, precisely in the absence of a cardinal symptom of increased intraocular pressure, more detailed procedures are required for an early assessment of the risk of glaucoma. Newer imaging methods such as HRT (scanning laser tomography), RTA (retinal thickness measurement), GDx ( scanning laser polarimetry ) or OCT ( optical coherence tomography ) allow significantly more refined diagnostics . Even minor damage can be recorded in a reproducible and detailed manner and thus offer significant diagnostic support for early stage assessment and follow-up controls.

Since normal pressure glaucomas mostly have a vascular (vessel-related) cause, and a typical characteristic of normal pressure glaucoma, such as the Flammer syndrome, which is often the basis for it, is low or fluctuating blood pressure, a 24-hour blood pressure measurement is considered useful.

treatment

If left untreated, normal pressure glaucoma gradually leads to the symptoms known from typical high pressure glaucoma: damage to the optic nerve with visual field defects and impaired vision . As is generally the case with glaucoma, it may be necessary to lower the intraocular pressure with eye drops or an operation. Patients with normal pressure glaucoma, whose intraocular pressure was reduced by at least 30%, showed significantly better treatment success than patients in whom such a pressure reduction did not take place. The setting must be made to the individual target pressure value. Disc hemorrhages are an indication of progression, a worsening of the optic nerve findings.

In addition to lowering the intraocular pressure, internal therapy for the underlying vascular disease is even more indicated for normal pressure glaucoma than for classic high pressure glaucoma. However, no standard treatment has yet been established here. Approaches to stabilizing blood pressure, in the sense of avoiding blood pressure values ​​that are too low or fluctuating, include dietary measures (high-salt diet) or the administration of low-dose medication to increase blood pressure - in modern medicine in industrialized nations, where high blood pressure is a widespread disease with numerous potential consequential damages, is an undoubtedly unusual approach. Close, interdisciplinary collaboration between ophthalmologists and internists in the treatment of such patients is important.

Sources and literature

  • Katarzyna Konieczka, Konstantin Gugleta: Glaucoma . Hans Huber, Bern 2015, ISBN 978-3456851464 .
  • Franz Grehn: Ophthalmology. 30th edition. Springer Verlag, Berlin 2008, ISBN 978-3-540-75264-6 .
  • Josef Flammer: Glaucoma. A manual for those affected, an introduction for those interested, a reference work for those in a hurry. 3rd, revised edition. Huber, Bern 2009, ISBN 978-3-456-84677-4 .
  • Norbert Pfeiffer: Glaucoma and Ocular Hypertension. Basics, diagnostics, therapy. 2nd Edition. Thieme, Stuttgart et al. 2005, ISBN 3-13-105852-8 .
  • Ilse Strempel: Glaucoma - more than an eye disease. Kaden Verlag, Heidelberg 2013, ISBN 978-3-942825-15-3 .
  • Guideline No. 15a by BVA and DOG : primary chronic open-angle glaucoma, normal pressure glaucoma and ocular hypertension

Individual evidence

  1. a b Ronald D. Barley: Glaucoma: A Vascular Neuropathy. In: Deutsches Ärzteblatt. 2008; 105 (11), pp. A-562 / B-500 / C-489
  2. RD Barley: How normal pressure glaucoma develops. In: Deutsches Ärzteblatt. 105; September 19, 2008: pp. A1961-A1962.
  3. M. Pekmazci et al: The characteristics of glaucoma in Japanese Americans. In: Arch Ophthalmol. 2009; 127, pp. 167-171.
  4. K. Konieczka, S. Fränkl: Primary vascular dysregulation and glaucoma (Primary Vascular Dysregulation and Glaucoma). In: Journal of Practical Ophthalmology. 2013; 34, pp. 207-215.
  5. RD Barley: Eye disorders with tinnitus and cold extremities. In: Deutsches Ärzteblatt. February 21, 2014; P. A308 – A309 PDF version
  6. M. Mim et al .: Metabolic syndrome as a risk factor in normal-tension glaucoma. In: Acta Ophthalmol. May 19, 2014. doi: 10.1111 / aos.12434 . [Epub ahead of print]
  7. ^ G. Bilgin: Normal-tension glaucoma and obstructive sleep apnea syndrome: a prospective study. In: BMC Ophthalmol. March 10, 2014; 14, p. 27. doi: 10.1186 / 1471-2415-14-27 .
  8. M. Pache: Sleep apnea and glaucoma. In: Clinical monthly sheets for ophthalmology. 2014; 231, pp. 127-129.
  9. D. Bach-Holm et al .: Normal tension glaucoma and Alzheimer disease: comorbidity? In: Acta Ophthalmol. 2012; 90, pp. 683-685.
  10. ^ J. Häntzschel et al .: Comparison of normal and high tension glaucoma: nerve fiber layer and optic nerve head damage. In: Ophthalmologica. 2014; 231, pp. 160-265.
  11. K. Konieczka and others: Unstable Oxygen Supply in Glaucoma. In: Clinical monthly sheets for ophthalmology. 2014; 231, pp. 121-126.
  12. M. Pache, J. Funk: High-tech in glaucoma diagnostics. In: Clinical monthly sheets for ophthalmology. Volume 223, No. 6, 2006, ISSN  0023-2165 , pp. 503-508, doi: 10.1055 / s-2005-859004 .
  13. AAD - Ophthalmological Academy of Germany ( Memento of the original from December 16, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / aad-kongress.de
  14. ^ Josef Flammer: Glaucoma. A manual for those affected, an introduction for those interested, a reference work for those in a hurry. 3rd, revised edition. Huber, Bern 2009, ISBN 978-3-456-84677-4 .
  15. Norbert Pfeiffer: Glaucoma and ocular hypertension. Basics, diagnostics, therapy. 2nd Edition. Thieme, Stuttgart et al. 2005, ISBN 3-13-105852-8 .
  16. JH Jeong et al .: Preperimetric normal tension glaucoma study: long-term clinical course and effect of therapeutic lowering of intraocular pressure. In: Invest Ophthalmol Vis Sci. 2014; 55, pp. 986-992.
  17. ^ Josef Flammer: Glaucoma. A manual for those affected, an introduction for those interested, a reference work for those in a hurry. 3rd, revised edition. Huber, Bern 2009, ISBN 978-3-456-84677-4 .