Elsevier

Ophthalmology

Volume 105, Issue 8, 1 August 1998, Pages 1557-1563
Ophthalmology

Identification of early glaucoma cases with the scanning laser ophthalmoscope1,

Presented as a paper at the Annual Meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, May 1997
https://doi.org/10.1016/S0161-6420(98)98047-2Get rights and content

Abstract

Purpose

This study aimed to define the confocal laser scanning ophthalmoscope (Heidelberg Retina Tomograph [HRT]) parameters that best separate patients with early glaucoma from normal subjects.

Study design

A cross-sectional study.

Participants

A total of 80 normal subjects and 51 patients with early glaucoma participated (average visual field mean deviation = −3.6 dB).

Intervention

Imaging of the optic nerve head with the HRT and analysis using software version 1.11 were performed.

Main outcome measures

The relation between neuroretinal rim area and optic disc area, and cup-disc area ratio and optic disc area, was defined by linear regression of data derived from the normal subjects. The normal ranges for these two parameters were defined by the 99% prediction intervals of the linear regression between the parameter and optic disc area, for the whole disc, and for each of the predefined segments. Normal subjects and patients were labeled as abnormal if the parameter for either the whole disc or any of the predefined segments was outside the normal range. The sensitivity and specificity values of the method were calculated.

Results

The highest specificity (96.3%) and sensitivity (84.3%) values to separate normal subjects and those patients with early glaucoma were obtained using the 99% prediction interval from the linear regression between the optic disc area and the log of the neuroretinal rim area. Similar specificity (97.5%) and lower sensitivity (74.5%) values were obtained with the 99% prediction interval derived from regression between the disc area and cup-disc area ratios. Poor separation between groups was obtained with the other parameters.

Conclusions

The HRT, using the technique of linear regression to account for the relationship between optic disc size and rim area or cup-disc area ratio, provides good separation between control subjects and patients with early glaucoma in this population.

Section snippets

Materials and methods

Two groups of white subjects were recruited prospectively for this study: control subjects and patients with early open-angle glaucoma. A full medical history was taken and detailed ocular examination performed. Subjects underwent Humphrey visual field testing with the 24–2 program (Humphrey Instruments, San Leandro, CA) and imaging of the optic disc with the HRT. Informed consent was obtained from each subject after the nature of the procedure was fully explained.

Normal control subjects were

Results

Eighty normal subjects and 51 patients with early glaucoma were enrolled in the study. The early glaucoma group included 37 patients from the glaucoma clinic and 14 patients from the ocular hypertensive clinic who have developed a reproducible field defect while under review. The characteristics of the study population are summarized in Table 1.

The mean SDs for the height values of the three HRT images, comprising the mean topographic image, were 28.26 for the normal group and 31.27 for the

Discussion

The HRT is a confocal scanning laser ophthalmoscope that provides us with quantitative optic nerve head measurements that have been shown to be highly reproducible.10, 11, 12, 13 The global optic disc parameters of our normal group (Table 2) are similar to those in previously published data.22, 23, 24 Those of the glaucoma group are similar to the values reported by Zangwill et al,23 and the differences with those in the study by Uchida et al24 may be explained by the disparity in the disc area

References (40)

  • A. Tuulonen et al.

    Initial glaucomatous optic disk and retinal nerve fiber layer abnormalities and their progression

    Am J Ophthalmol

    (1991)
  • J.B. Jonas et al.

    Pattern of glaucomatous neuroretinal rim loss

    Ophthalmology

    (1993)
  • R.J. Britton et al.

    The area of the neuroretinal rim of the optic nerve in normal eyes

    Am J Ophthalmol

    (1987)
  • D.M.I. Montgomery

    Clinical disc biometry in early glaucoma

    Ophthalmology

    (1993)
  • D.M. Montgomery

    Measurement of optic disc and neuroretinal rim areas in normal and glaucomatous eyes. A new clinical method

    Ophthalmology

    (1991)
  • A. Sommer et al.

    Optic disc parameters and onset of glaucomatous field loss. I. Methods and progressive changes in disc morphology

    Arch Ophthalmol

    (1979)
  • J.E. Pederson et al.

    The mode of progressive disc cupping in ocular hypertension and glaucoma

    Arch Ophthalmol

    (1980)
  • A. Sommer et al.

    The nerve fiber layer in the diagnosis of glaucoma

    Arch Ophthalmol

    (1977)
  • A. Sommer et al.

    Evaluation of nerve fiber layer assessment

    Arch Ophthalmol

    (1984)
  • A. Sommer et al.

    Clinically detectable nerve fiber atrophy precedes the onset of glaucomatous field loss

    Arch Ophthalmol

    (1991)
  • Cited by (381)

    • Comprehensive Glaucoma Imaging

      2022, Albert and Jakobiec's Principles and Practice of Ophthalmology: Fourth Edition
    View all citing articles on Scopus

    Supported by a grant from The Guide Dogs for the Blind Association, Reading, UK. (DFG-H).

    1

    The authors have no proprietary interest in the development or marketing of this or a competing instrument.

    View full text