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Klin Monbl Augenheilkd 2017; 234(04): 468-473
DOI: 10.1055/s-0042-123725
Klinische Studie
Georg Thieme Verlag KG Stuttgart · New York

A New Glaucoma Severity Score Combining Structural and Functional Defects

Systematische Einteilung des Glaukomstadiums unter Berücksichtigung struktureller und funktioneller Defekte
J. Wachtl
1   University Hospital Zurich, Department of Ophthalmology, Zurich, Switzerland
2   Talacker Eye Center Zurich (TAZZ), Zurich, Switzerland
,
M. Töteberg-Harms
1   University Hospital Zurich, Department of Ophthalmology, Zurich, Switzerland
,
S. Frimmel
1   University Hospital Zurich, Department of Ophthalmology, Zurich, Switzerland
,
C. Kniestedt
1   University Hospital Zurich, Department of Ophthalmology, Zurich, Switzerland
2   Talacker Eye Center Zurich (TAZZ), Zurich, Switzerland
› Author Affiliations
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Publication History

Publication Date:
31 January 2017 (online)

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Abstract

Background In order to assess glaucoma severity and to compare the success of surgical and medical therapy and study outcomes, an objective and independent staging tool is necessary. A combination of information from both structural and functional testing is probably the best approach to stage glaucomatous damage. There has been no universally accepted standard for glaucoma staging. The aim of this study was to develop a Glaucoma Severity Score (GSS) for objective assessment of a patientʼs glaucoma severity, combining both functional and structural information.

Materials and methods The Glaucoma Severity Score includes the following 3 criteria: superior and inferior Retinal Nerve Fibre Layer (RNFL) thickness, perimetric mean defect (MD), and agreement of anatomical and perimetric defects, as assessed by two glaucoma specialists. The specialists defined a staging tool for each of the 3 criteria in a consensus process, assigning specific characteristics to a scale value between 0 and 2 or 0 and 3, respectively. The GSS ranges between 0 and 10 points. In a prospective observational study, the data of 112 glaucoma patients were assessed independently by the two specialists according to this staging tool.

Results The GSS was applied to 112 eyes and patients (59.8 % female) with a mean age of 66.3 ± 13.1 years. Mean GSS was 4.73 points. Cohenʼs kappa coefficient was determined to measure inter-rater agreement between glaucoma specialists for the third criterion. With κ = 0.83, the agreement was very good. Thus, all 3 criteria of the GSS may be regarded as objective.

Conclusions The Glaucoma Severity Score is an objective tool, combining both structural and functional characteristics, and permitting comparison of different patients, populations and studies. The Glaucoma Severity Score has proven effective in the objective assessment of 112 glaucoma patients and is relatively user-friendly in clinical practice. A comparative study of the GSS with the results of the FORUM® Glaucoma Workplace (Carl Zeiss Meditec AG, Jena, Germany) will be the next step. If outcomes match, the Glaucoma Severity Score can be accepted as a promising tool to stage glaucoma and monitor changes objectively in patients when comparing glaucoma progression in study analyses.

Zusammenfassung

Hintergrund Zur Beurteilung des Glaukomstadiums, zum Vergleich von operativen und medikamentösen Therapieerfolgen sowie von Studienergebnissen ist ein objektives Graduierungssystem notwendig. Von Vorteil ist ein Ansatz, der funktionelle und strukturelle Untersuchungsergebnisse kombiniert. Bis dato hat sich international kein Beurteilungssystem des Glaukomstadiums durchsetzen können. Das Ziel dieser Studie war die Entwicklung eines Glaucoma Severity Scores (GSS), der Funktion, Struktur und objektive Beurteilung kombiniert.

Material und Methoden Der Glaucoma Severity Score beinhaltet folgende 3 Kriterien: retinale peripapilläre Nervenfaserschichtdicke (superior und inferior), perimetrischer mittlerer Defekt und den Konsens über anatomische und perimetrische Defekte durch 2 Glaukomspezialisten. Für jede der 3 Dimensionen werden spezifische Merkmale festgelegt, die eine Zuordnung zu einem Skalenwert zwischen 0 und 2 resp. 3 Punkten pro beurteilter Domäne erlauben. Das Graduierungssystem reicht von 0 bis zu 10 Punkten. Der GSS wird in einer prospektiven Beobachtungsstudie an 112 Patienten getestet.

Ergebnisse Der GSS wurde anhand von 112 Patienten (59,8 % Frauen) mit einem durchschnittlichen Alter von 66,3 ± 13,1 Jahren getestet. Der durchschnittliche GSS betrug 4,73 Punkte. Cohens Kappa-Koeffizient als statistisches Maß für die Interrater-Reliabilität zwischen den Glaukomspezialisten für das 3. Kriterium betrug κ = 0,83. Dies entspricht einer sehr guten Übereinstimmung, weshalb alle 3 Kriterien des Index als objektiv betrachtet werden können.

Schlussfolgerungen Der Glaucoma Severity Score erlaubt eine objektive Beurteilung des Glaukomstadiums verschiedener Patienten und bietet somit eine optimierte Vergleichsmöglichkeit von Studienergebnissen und Therapieerfolgen. Für die optimale Beurteilung des Glaukomstadiums sind im GSS strukturelle und funktionelle Eigenschaften kombiniert. In einem nächsten Schritt soll der GSS mit dem FORUM® Glaucoma Workplace (Carl Zeiss Meditec AG, Jena, Deutschland) verglichen werden. Stimmen die Resultate überein, ist der GSS ein erfolgssversprechendes Instrument zur objektiven Beurteilung von Glaukomstadium und Progression, und könnte zum Vergleich verschiedener Patienten und Studienergebnisse dienen.

Key words

glaucoma - glaucoma staging system - score - retinal nerve fibre layer

Schlüsselwörter

Glaukom - Glaukom Staging - Glaukomprogression - retinale peripapilläre Nervenfaserschichtdicke
 

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