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Abstract

Purpose

To perform qualitative evaluation of the aqueous humor (AH) outflow mechanism in glaucoma and nonglaucoma patients by means of tonography assessment and mathematical analysis.

Methods

Sixty-two primary open angle and 58 pseudoexfoliation glaucoma patients were recruited in a non-interventional, observational study between 2004 and 2007. Qualitative and quantitative outflow assessment was acquired by means of a digital tonographer and mathematical analysis. Qualitative results were represented using slope analysis of the change of the AH outflow rate over the tonography study. The results were compared to the control group (CG; n=100) as well as to a pseudoexfoliation group (PEX; n=46).

Results

Regarding quantitative analysis, glaucoma groups exhibited significantly lower outflow facility compared to nonglaucoma ones (p<0.001). Outflow facility value was significantly correlated to cup to disc ratio (Pearson correlation r=–0.3, p<0.001). Regarding qualitative analysis, the primary open-angle glaucoma (POAG) group presented a significant profile variation at the beginning of the tonography, expressed as an increased resistance of the AH outflow. Both glaucoma groups exhibited profile stabilization at the end of the measurement, suggesting that the outflow rate remained constant, while nonglaucoma groups followed a continuous reduction of the AH outflow rate throughout the study.

Conclusions

The POAG, PXG, PEX, and CG groups demonstrated both qualitative and quantitative tonographic profile differences. The observed differences in the glaucoma groups suggest a distinct pathomechanism between POAG and PXG. It is suggested that POAG patients have a temporary disruption of the AH flow pathway, while PXG patients have a generalized increased flow resistance.

Keywords

Aqueous outflow DAHOM Glaucoma Tonography

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References

Quigley

H.A.

. Number of people with glaucoma worldwide. Br J Ophthalmol 1996; 80: 389–93.

Kozobolis

V.P.

, Detorakis

E.T.

, Tsilimbaris

, Siganos

D.S.

, Vlachonikolis

I.G.

, Pallikaris

I.G.

. Crete, Greece glaucoma study. J Glaucoma 2000; 9: 143–9.

Konstas

A.G.

, Mantziris

D.A.

, Stewart

W.C.

. Diurnal intraocular pressure in untreated exfoliation and primary open-angle glaucoma. Arch Ophthalmol 1997; 115: 182–5.

Sugar

. Pigmentary glaucoma and the glaucoma associated with the exfoliation-pseudoexfoliation syndrome: update. Robert N. Shaffer lecture. Ophthalmology 1984; 91: 307–10.

Ritch

. Exfoliation syndrome: the most common identifiable cause of open-angle glaucoma. J Glaucoma 1994; 3: 176–7.

Tarkkanen

A.H.

. Exfoliation syndrome. Trans Ophthalmol Soc UK 1986; 105: 233–6.

Layden

W.E.

, Shaffer

R.N.

. Exfoliation syndrome. Am J Ophthalmol 1974; 78: 835–41.

Smith

R.J.

. Nature of glaucoma in the pseudoexfoliation syndrome. Trans Ophthalmol Soc UK 1979; 99: 308–9.

Wollensak

, Becker

H.U.

, Seiler

. Pseudoexfoliation syndrome and glaucoma. Does glaucoma capsulare exist? Ger J Ophthalmol 1992; 1: 32–4.

10.

Schlötzer-Schrehardt

, Naumann

G.O.

. Trabecular meshwork in pseudoexfoliation syndrome with and without open-angle glaucoma. A morphometric, ultrastructural study. Invest Ophthalmol Vis Sci 1995; 36: 1750–64.

11.

Madden

J.G.

, Crowley

M.J.

. Factors in the exfoliation syndrome. Br J Ophthalmol 1982; 66: 432–7.

12.

Leske

M.C.

, Heijl

, Hussein

, Bengtsson

, Hyman

, Komaroff

; Early Manifest Glaucoma Trial Group. Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. Arch Ophthalmol 2003; 121: 48–56.

13.

Ekström

. Elevated intraocular pressure and pseudoexfoliation of the lens capsule as risk factors for chronic open-angle glaucoma. A population-based five-year follow-up study. Acta Ophthalmol 1993; 71: 189–95.

14.

Alm

, Nilsson

S.F.

. Uveoscleral outflow: a review. Exp Eye Res 2009; 88: 760–8.

15.

Feghali

J.G.

, Azar

D.T.

, Kaufman

P.L.

. Comparative aqueous outflow facility measurements by pneumatonography and Schiotz tonography. Invest Ophthalmol Vis Sci 1986; 27: 1776–80.

16.

Drance

S.M.

. Correlation between optic disc changes and visual field defects in chronic open-angle glaucoma. Trans Sect Ophthalmol Am Acad Ophthalmol Otolaryngol 1976; 81: 224–6.

17.

Johnson

T.V.

, Fan

, Camras

C.B.

, Toris

C.B.

. Aqueous humor dynamics in exfoliation syndrome. Arch Ophthalmol 2008; 126: 914–20.

18.

Kozobolis

V.P.

, Paschalis

E.I.

, Foudoulakis

N.C.

, Koukoula

S.C.

, Labiris

. The digital aqueous humor outflow meter: an alternative tool for screening of the human eye outflow facility. Clin Ophthalmol 2010; 4: 937–45.

19.

Hitchings

R.A.

, Spaeth

G.L.

. The optic disc in glaucoma II: correlation of the appearance of the optic disc with the visual field. Br J Ophthalmol 1977; 61: 107–13.

20.

Chylack

L.T.

Jr , Leske

M.C.

, McCarthy

, Khu

, Kashiwagi

, Sperduto

. Lens opacities classification system II (LOCS II). Arch Ophthalmol 1989; 107: 991–7.

21.

Moses

R.A.

. The Goldmann applanation tonometer. Am J Ophthalmol 1958; 46: 865–9.

22.

Friedenwald

J.S.

. Tonometer calibration; an attempt to remove discrepancies found in the 1954 calibration scale for Schiotz tonometers. Trans Am Acad Ophthalmol Otolaryngol 1957; 61: 108–22.

23.

Friedenwald

J.S.

. Some problems in the calibration of tonometers. Am J Ophthalmol 1948; 31: 935–44.

24.

Pallikaris

I.G.

, Kymionis

G.D.

, Ginis

H.S.

, Kounis

G.A.

, Tsilimbaris

M.K.

. Ocular rigidity in living human eyes. Invest Ophthalmol Vis Sci 2005; 46: 409–14.

25.

Johnson

D.H.

, Brubaker

R.F.

. Dynamics of aqueous humor in the syndrome of exfoliation with glaucoma. Am J Ophthalmol 1982; 93: 629–34.

26.

Acott

T.S.

, Kelley

M.J.

. Extracellular matrix in the trabecular meshwork. Exp Eye Res 2008; 86: 543–61.

27.

Bradley

J.M.

, Kelley

M.J.

, Zhu

, Anderssohn

A.M.

, Alexander

J.P.

, Acott

T.S.

. Effects of mechanical stretching on trabecular matrix metalloproteinases. Invest Ophthalmol Vis Sci 2001; 42: 1505–13.

28.

Määttä

, Tervahartiala

, Harju

, Airaksinen

, Autio-Harmainen

, Sorsa

. Matrix metalloproteinases and their tissue inhibitors in aqueous humor of patients with primary open-angle glaucoma, exfoliation syndrome, and exfoliation glaucoma. J Glaucoma 2005; 14: 64–9.

29.

Rönkkö

, Rekonen

, Kaarniranta

, Puustjärvi

, Teräsvirta

, Uusitalo

. Matrix metalloproteinases and their inhibitors in the chamber angle of normal eyes and patients with primary open-angle glaucoma and exfoliation glaucoma. Graefes Arch Clin Exp Ophthalmol 2007; 245: 697–704.

30.

Schlötzer-Schrehardt

, Naumann

G.O.

. Trabecular meshwork in pseudoexfoliation syndrome with and without open-angle glaucoma. A morphometric, ultrastructural study. Invest Ophthalmol Vis Sci 1995; 36: 1750–64.

31.

Kozobolis

V.P.

, Papatzanaki

, Vlachonikolis

I.G.

, Pallikaris

I.G.

, Tsambarlakis

I.G.

. Epidemiology of pseudoexfoliation in the island of Crete (Greece). Acta Ophthalmol Scand 1997; 75: 726–9.

32.

Alm

, Nilsson

S.F.

. Uveoscleral outflow: a review. Exp Eye Res 2009; 88: 760–8.

33.

Grant

W.M.

. Clinical measurements of aqueous outflow. AMA Arch Ophthalmol 1951; 46: 113–31.

34.

Grant

W.M.

. Tonographic method for measuring the facility and rate of aqueous flow in human eyes. Arch Ophthalmol 1950; 44: 204–14.

35.

Barany

E.H.

. A mathematical formulation of intraocular pressure as dependent on secretion, ultrafiltration, bulk outflow and osmotic reabsorption of fluid. Invest Ophthalmol Vis Sci 1963; 2: 584–90.

36.

Kupfer

. Pseudofacility in the human eye. Trans Am Ophthalmol Soc 1971; 69: 383–96.

37.

Dausch

, Wachholz

E.A.

, Honegger

. Tonography test according to Leydhecker. Clinical comparison by tonography according to Grant (author's transl). Klin Monatsbl Augenheilkd 1975; 166: 59–64.

38.

Brubaker

R.F.

. Physiology of aqueous humor formation. In: Drance

, Neufeld

, eds. Applied Pharmacology in the Medical Treatment of Glaucoma. New York: Grune & Stratton; 1984: 51–3.

39.

Moses

R.A.

, Grodzki

W.J.

Jr , Carras

P.L.

. Pseudofacility. Where did it go? Arch Ophthalmol 1985; 103: 1653–5.

40.

Hart

M.W.

. Intraocular pressure. In: Adler's Physiology of the Eye, 9th ed. St Louis: Mosby; 1992: 257.

41.

Kotecha

, Lim

, Garway-Heath

. Tonometry and intraocular pressure fluctuation. In: Glaucoma, vol 1, 1st ed. Philadelphia: Saunders; 2009: 109.

Tonography assessment using quantitative and qualitative analysis of the aqueous humor outflow mechanism

Abstract

Purpose

Methods

Results

Conclusions

Keywords

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References