The diagnosis of primary open-angle glaucoma (POAG) is based on the coexistence of an intraocular pressure (IOP) increase, perimetric alterations and morphological alterations to the optic nerve head and the retinal nerve fibre layer. Studies published in the literature (Sommer 1979; Pederson & Anderson 1980; Caprioli 1989; Tuulonen & Airaksinen 1991; Zeyen & Caprioli 1993; Caprioli 1996) have pointed out that the anatomical changes to the optic disk and the retinal nerve fibre layer may precede the perimetric deficits by years. From when the pharmacological treatment of ocular hypertension in its initial stages showed it could slow down or even block the progression of the disease (Mao 1991; Chauhan and Drance 1992; Migdal 1994), it has been imperative to make the diagnosis of glaucoma in its initial phase. To do this, in addition to the perimetric examination, there are now the interesting prospectives of the methods using computed digital analysis of the optic nerve head and the retinal nerve fibre layer, among which the Heidelberg retina tomograph (HRT) is one that furnishes a detailed, reproducible and above all objective evaluation. This work was undertaken to evaluate the changes in the morphology of the optic nerve head and retinal fibre layer as well as in the visual field in eyes with ocular hypertension or POAG in its initial phase. Our research was conducted on 17 patients (24 eyes) with a mean age of 62.0 ± 10.7 years in our out-patient glaucoma centre at the eye clinic of the University of Turin who were found to have IOP values >22 mmHg. All the patients had a complete oculistic check and morphological examination of the optic disk and the retinal nerve fibre layer by the Heidelberg retina tomograph (HRT software 2.01) with a visual field of 15° × 15°. Three series of images were recorded for each eye. For analysis purposes, a topographic image created by the computer representing the mean of the three images obtained was used and, onto this, an expert examiner drew the contour line of the internal edge of the Elschnig scleral ring. A computed visual field examination by the perimeter OCTOPUS 2000 (program G1, central 30°, Peritrend analysis) was also made. All the patients had had at least 2 previous examinations with values of RF < 15%. The inclusion and exclusion criteria for enrolment in the study were as follows. Inclusion: IOP values >22 mmHg without therapy; visual acuity values ≥8/10; transparent dioptric means; MD < 6 dB; good collaboration at the HRT examination; good collaboration at the perimetric examination (RF < 15%). Exclusion: congenital malformation of the ocular apparatus; opacity of the dioptric means; presence of elevated refractive defects (>±3D for myopia and hypermetropia and >±1.5D for astigmatism); previous vascular and/or neurological pathologies of the retinal vessels and/or the optic nerve; impossibility of lending a suitable collaboration in the perimetric and morphological examinations; heavy smoking (>15 cigarettes/day); heavy drinking (>60 g/day alcohol). In 7 (29.16%) of the 24 eyes enrolled, there were no visual field alterations at base time. Mean IOP base values were 25.15 ± 3.21 mmHg. All the patients were prescribed a local antiglaucoma therapy. After a mean follow-up period of 426.6 ± 161.2 days during which the patients were given routine checks which always showed good tonometric control (IOP < 20 mmHg), the optic disk morphological and perimetric examinations were repeated. With regard to the HRT, those parameters were analysed that, on the basis of the data in the literature and our personal experience, were known to be of greater sensitivity and specificity: CA, C/D ratio, RA, RV, CSM, mRNFLt and RNFLcsa. As to the perimetric indices, we considered the mean defect (MD) and the defect corrected variance (CLV). In addition, an analysis by sector was made for both the morphological and the functional data, dividing the disk into 4 quadrants (0–90°, 90–180°, 180–270°, 270–360°). First, we analysed the data overall by Student's t-test in order to find out if the HRT parameter values were subject to significant modifications between the first and second examinations, independently of the follow-up time between them. Then, for the disk HRT parameters overall, the anova was calculated for corrected repeated measurements for the 2 subgroups of eyes with: subgroup 1 – mean follow-up between 161 and 450 days; subgroup 2 – mean follow-up between 451 and 755 days. The statistically significant threshold was fixed at 5% (P < 0.05). Also evaluated was the correlation between the anatomic and the functional data relating to the optic disk totally and to the 4 quadrants by Pearson's r test. In all the eyes, an increase of the mean defect over base time was observed (MD from 2.5 ± 1.8 dB to 4.0 ± 1.4 dB; +37.5%) and also of the defect corrected variance (CLV from 2.8 ± 1.7 dB to 4.49 ± 4.49 dB; +37.63%). The data obtained were statistically significant (P < 0.05). In particular, a functional damage (MD > 2 dB) was found in 7 eyes with hypertension. In so far as sector analysis was concerned, the superior temporal proved to have the most functional deficit (MD from 3.1 ± 1.9 dB to 4.3 ± 2.0 dB, +27.90%; P < 0.05). Base time HRT parameters are exhibited in Table 1. At follow-up end, there was a tendency to RNFL thinning and optic disk morphology changes towards glaucoma, also confirmed by sector analysis. The anova analysis results for repeated measurements (F) showed the variations to be not statistically significant (Table 2). There were good correlations at base time between MD and CA (r: 0.32), C/D ratio (r: 0.31) and CSM (r: 0.53). Data relating to the 4 quadrants showed a good correlation between MD and all the HRT parameters considered in the TS sector. So far as the CLV was concerned, there was a good correlation for all the parameters with the exception of CA and C/D ratio. At follow-up end, there was found an increase in the values of the perimetric indices, in particular the MD which was statistically significant. In 7 eyes which had normal visual field at base time there were found glaucoma-type changes. The optic disk and nerve fibre layer morphology had not changed significantly. The evolution of the functional damage might very possibly be a late consequence of the morphological changes already present at base time even in the ocular hypertensive eyes. That no significant changes were found in the HRT parameters might be due to the good tonometric compensation obtained through the local therapy. Further data to confirm or belie these hypotheses may be had by continuing to monitor these patients.

Acta Ophthalmologica ScandinavicaVolume 78, Issue S232 p. 29-31 Free Access Topographic sector-by-sector analysis of the optic nerve head by HRT and correlation with frank glaucoma perimetric indices T. Rolle, T. Rolle Eye Clinic, University of TurinSearch for more papers by this authorS. Salvini, S. Salvini Eye Clinic, University of TurinSearch for more papers by this authorC. Favero, C. Favero Eye Clinic, University of TurinSearch for more papers by this authorE. Borasio, E. Borasio Eye Clinic, University of TurinSearch for more papers by this authorM. Manea, M. Manea Eye Clinic, University of TurinSearch for more papers by this authorB. Brogliatti, B. Brogliatti Eye Clinic, University of TurinSearch for more papers by this authorF. M. Grignolo, F. M. Grignolo Eye Clinic, University of TurinSearch for more papers by this author T. Rolle, T. Rolle Eye Clinic, University of TurinSearch for more papers by this authorS. Salvini, S. Salvini Eye Clinic, University of TurinSearch for more papers by this authorC. Favero, C. Favero Eye Clinic, University of TurinSearch for more papers by this authorE. Borasio, E. Borasio Eye Clinic, University of TurinSearch for more papers by this authorM. Manea, M. Manea Eye Clinic, University of TurinSearch for more papers by this authorB. Brogliatti, B. Brogliatti Eye Clinic, University of TurinSearch for more papers by this authorF. M. Grignolo, F. M. Grignolo Eye Clinic, University of TurinSearch for more papers by this author First published: 25 August 2010 https://doi.org/10.1111/j.1600-0420.2000.tb01088.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References Caprioli J. & Spaeth GL (1987): Looking for better ways to measure the optic disc. Ophthalmic Surg 18: 866. Drance SM, Airaksinen PJ, Price M., Schulzer M., Douglas GR & Tansley BW (1986): The correlation of functional and structural measurements in glaucoma patients and normal subjects. Am J Ophthalmol 102: 612– 616. Pederson JE & Anderson DR. (1980): The mode of progressive disc cupping in ocular hypertension and glaucoma. Arch Ophthalmol 98: 490– 495. Rolle T., Bogetto C., Salvini S., Favero C. & Brogliatti B. (1999): Impiego dell'Heidelberg Retina Tomograph nello studio del glaucoma con iniziale danno perimetrico. Atti, XXIV S.O.N.O. Congress, 1–2 October, 1999, Cuneo (in press). Rolle T., Salvini S., Bogetto C., Favero C., Brogliatti B. & Grignolo FM (1999): Studio del danno perimetrico iniziale di tipo glaucomatoso: confronto tra i dati del campo visivo e l'analisi morfologica della papilla mediante Heidelberg Retina Tomograph Presented at the S.I.P. Meeting and 6th National Congress, 25–26 November, 1999, Rome. Iester M. & Mikelberg FS (1999): Optic nerve head morphologic characteristics in high-tension and normal-tension glaucoma. Archives of Ophthalmology 117(8): 1010– 1013. Lachenmayr BJ, Drance SM & Airaksinen PJ (1992): Diffuse field loss and diffuse retinal nerve fiber loss in glaucoma. German J Ophthalmol 1: 22– 25. Mikelberg FS, Wijsman K. & Schulzer M. (1993): Reproducibility of topographic parameters obtained with the Heidelberg Retina Tomograph. J Glaucoma 2: 101– 103. Volume78, IssueS232December 2000Pages 29-31 ReferencesRelatedInformation