[Transitory intrathoracic and -abdominal pressure elevation in the history of 64 patients with normal pressure glaucoma].

BACKGROUND

As one pathogenetic factor in normal-tension glaucoma an individually elevated sensitivity of lamina cribrosa regarding intraocular pressure fluctuations is postulated. Aim of this study was to evaluate patients with normal-tension glaucoma for the exposure to potential, clinically undetected transient elevations of intraocular tension due to increased intrathoracic and -abdominal pressure.

PATIENTS AND METHODS

A survey of 64 patients of the "Erlanger Glaucoma registry" with normal-tension glaucoma (NTG) and 64 patients with primary open angle glaucoma (pOAG) as control group were performed with regard to activities respectively diseases causing intrathoracic or -abdominal pressure elevation (1. weight lifting, 2. playing high resistance wind instruments, 3. chronic asthma/cough, 4. obstruction of the urinary system, 5. constipation). Both groups were matched regarding age (median: 61 years), sex (24 male, 40 female), visual field defects (mean defect: NTG 4.4; pOAG 4.7), visual acuity (median 1.0 +/- 0.2) and systemic diseases (diabetes mellitus, hypertension, cardiac disease).

RESULTS

Among patients with NTG there were 45% (29/64 patients) with activities respectively diseases causing intrathoracic or intraabdominal pressure elevation in their medical history compared to 11% (7/64) among patients with pOAG. Male patients with normal-tension glaucoma showed with 62% the highest frequency of such activities (among them 4/24 high resistance wind instrument playing, 5/24 urinary system obstructions, 4/24 long time weight lifting). Female patients with normal-tension glaucoma most frequently presented with a history of weight lifting (11/40).

CONCLUSION

Patients with glaucomatous optic nerve atrophy without evident intraocular pressure elevation compared to patients with pOWG more frequently report activities or diseases causing intrathoracic/-abdominal pressure elevation in their medical history. This may suggest an additional pathomechanism in normal-tension glaucoma. Therefore patients may be adviced on these potential risk factors.