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EDITORIALS: David B Henson and Reshma Thampy Preventing blindness from glaucoma BMJ 2005; 331: 120-121 [Full text]

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Glaucoma- optic disc or visual field assessment

James E Morgan, Michael Austin, Consultant Ophthalmologist, Singleton Hospital   (20 August 2005)

Glaucoma- optic disc or visual field assessment 20 August 2005
James E Morgan, Reader in Ophthalmology, Cardiff University CF11 9HL, Michael Austin, Consultant Ophthalmologist, Singleton Hospital Send response to journal: Re: Glaucoma- optic disc or visual field assessment	We read with interest Professors Henson’s editorial on the difficulties in detecting patients with glaucoma who are at risk of blindness1. We agree that the more widespread use of existing technologies will probably be the most cost effective solution to the early detection of disease. However, while the detection of definite glaucoma cases in the North London trial indicates the value of using the conventional triad of diagnostic techniques (visual field, intraocular pressure and optic disc examination) for the detection of disease2, it does not address the issue of detecting patients with early disease. It is now clear that reliance on visual field evaluation for the detection of glaucoma will bias toward late detection since changes in the optic nerve precede visual field loss by as much as 6 years in some studies3. Indeed, the presence of visual field loss is no longer regarded as a prerequisite for the diagnosis of glaucoma. Accurate clinical assessment of the optic nerve, either by new technologies or by conventional ophthalmoscopy has assumed greater importance in the clinical diagnosis of glaucoma with visual field examination playing a key role in monitoring advanced disease. If we can detect early glaucoma damage at the level of the optic nerve rather than the visual field then we can prevent patients moving to the group where they will present with advanced visual field loss. Unfortunately, the clinical evaluation of the optic nerve remains a problem area since the agreement between optic nerve assessments can be poor. We suggest that training and technical resources are directed to improve the quality of clinical optic nerve head examination in glaucoma. Future glaucoma management pathways should be designed to detect patients with minimal, rather than reliably detectable visual field loss. References 1 Henson DB, Thampy R. Preventing blindness from glaucoma. Bmj 2005; 331: 120-1. 2 Reidy A, Minassian DC, Vafidis G et al. Prevalence of serious eye disease and visual impairment in a north London population: population based, cross sectional study. Bmj 1998; 316: 1643-6. 3 Sommer A, Katz J, Quigley H. Clinically detectable nerve fiber layer atrophy precedes the onset of glaucomatous field loss. Acta Ophthalmologica 1991; 109: 77-83. Competing interests: None declared