Using lasers to image the retinaBMJ 1999; 319 doi: http://dx.doi.org/10.1136/bmj.319.7220.1303 (Published 13 November 1999) Cite this as: BMJ 1999;319:1303
- James E Morgan, senior lecturer ([email protected])
- Cardiff Eye Unit, University Hospital of Wales, Cardiff CF4 4XW
High quality ophthalmic care depends on the accurate assessment of ocular disease. Conventional direct ophthalmoscopy is used widely and provides good two dimensional views of the retina. However, the true nature of retinal disease is apparent only in three dimensions. In diabetic maculopathy, direct ophthalmoscopy can reveal retinal exudates, but the degree of macula oedema, which usually underlies the decision to treat by laser photocoagulation,1 is less clear. In glaucoma, the earliest damage can be seen as thinning of the retinal nerve fibre layer with increased cupping of the optic disc.2 These changes are best viewed stereoscopically. In both cases, disease of the retinal or optic nerve head will change the surface contour of the retina, either elevating or depressing the retinal surface by up to several hundred micrometres. Clearly, the objective quantification of these changes would be of immense benefit in diagnosing disease and monitoring disease progression and response to treatment.
In diseases such as diabetic maculopathy and glaucoma changes in retinal structure precede visual symptoms
Earlier detection of these changes allows early intervention and improves the prognosis
Scanning laser ophthalmoscopes provide rapidly acquired views of the retina that enable the detection of these early changes
Clinical studies have shown the value of these devices in the diagnosis of glaucoma and diabetic maculopathy
The costs of these devices is falling and serious consideration should be given to their introduction into hospital based eye services
Techniques for retinal imaging
The three dimensional imaging of the retina has been facilitated by two technical developments. The first is the availability of cheap and powerful computers. The second is the production of affordable optoelectronics such as digital cameras and diode lasers. The incorporation of some of these technologies into clinical practice has been relatively straightforward and will be familiar to doctors in other specialties. For …
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