The Moorfields Regression Analysis improves the management of glaucoma
12 December 2014
Neural tissue in the optic nerve head is reduced by glaucoma. UCL researchers developed a diagnostic algorithm for measuring the amount of neural tissue relative to normal. This was incorporated into the Heidelberg Retina Tomograph, a standard imaging device, revolutionising the use of imaging in the clinical management of glaucoma.
Glaucoma is known as 'the silent thief of sight' because most people with glaucoma have no early symptoms or pain. By the time a patient is aware of vision loss, the disease is usually quite advanced. Late diagnosis is one of the most important risk factors for glaucoma blindness. Left undiagnosed and untreated, glaucoma can lead to irreversible blindness. If the condition is detected early enough, it is often possible to halt its development or delay its progression with medical or surgical treatment. Diagnostic and monitoring techniques, therefore, play a pivotal role in glaucoma management.
Glaucomatous features can be identified by examining the optic nerve head (ONH) with a slit lamp microscope, the instrument most frequently used by ophthalmologists, or with high-resolution photography (stereoscopic photography). These techniques, however, are subjective and they cannot be used to adequately quantify the amount of damage. Because of these limitations, optimal use of structural examinations in glaucoma had not been made and glaucoma management mostly relied on visual field (VF) testing. The introduction of quantitative imaging techniques laid the foundations for objective analysis of the ONH. However, these techniques lacked an adequate algorithm to classify the extent ONH damage with respect to normal limits.
To address this need, Professor David Garway-Heath and his team developed the Moorfields Regression Analysis (MRA), for one of the earliest and best-established imaging devices, the Heidelberg Retina Tomograph (HRT). The HRT measures the amount of neural tissue present in the ONH, which is reduced by glaucoma. The MRA enabled the classification of ONH damage and revolutionised the use of imaging in the clinical management of glaucoma.
The inclusion of the Moorfields Regression Analysis developed with Professor Garway-Heath has been one of the contributing factors to the adoption and success of the HRT within the glaucoma community. MRA has become synonymous with HRT and is considered one of the most important single tests for the early diagnosis of glaucoma - Heidelberg Engineering
The diagnostic and predictive power of the MRA
has led to the worldwide acceptance that imaging of the ONH should be performed
in addition to VF monitoring, in order to characterise glaucomatous damage to the eye. The MRA has
also become a 'reference standard' for establishing the performance of other
imaging devices in establishing whether or not glaucoma is present and in
predicting its development in patients with high IOP. The worldwide scale of
use of this technology is substantial. At Moorfields Eye Hospital alone,
over 32,000 patients have benefited over the last five years.