Vision symptoms plus retinal changes trigger need for AMD intervention

Aug 22 2012

By Sarah Guy, medwireNews Reporter

An analysis of over 1000 individuals presenting with suspected exudative age-related macular degeneration (AMD) has revealed which factors are most predictive of the need for treatment.

The presence of distorted vision including metamorphosia and dyschromatopsia, and ophthalmoscopic detection of retinal hemorrhages and exudates are all indicators for treatment intervention, say the researchers.

The findings might improve the primary triage of patients with exudative AMD and save money by not treating those whose symptoms do not call for it, suggest Toke Bek and colleagues from Århus University in Denmark.

"The introduction of vascular endothelial growth factor (VEGF) inhibitors for the treatment of exudative AMD has increased the referral rates of AMD patients with visual symptoms," they explain in Acta Ophthalmologica.

"However, a large proportion of the referred patients do not require treatment, implying that considerable resources would be saved if these patients could be identified on the basis of the clinical data available."

The study cohort included 1652 participants who underwent structured interviews regarding symptoms, as well as clinical evaluation with ophthalmoscopy and optical coherence tomography scanning.

Overall, all patient variables, except for the presence and duration of micropsia, differed significantly between those who qualified for VEGF and those who did not, say the researchers. For example, rates of blurred vision and metamorphopsia in these two groups were 83% versus 74%, and 51% versus 40%, respectively.

The team conducted a multivariate analysis to account for the interdependence of symptoms and clinical variables. This left the presence of metamorphopsia (odds ratio [OR]=1.64), micropsia (OR=0.59), dyschromatopsia (OR=1.65), retinal hemorrhages (9.53), and exudates (OR=20.1), as well as increasing central retinal thickness (OR=1.002 per micron), significantly independently associated with qualifying - or not, in the case of micropsia - for treatment.

After further adjustment, first for the presence of retinal hemorrhages, and second for both presence of hemorrhages and exudates, the presence of a central dark spot (OR=1.42) and the sudden onset and subsequent worsening of symptoms (ORs=1.45, 1.37 ), and the presence of blurred vision (OR=1.47), and reduced visual acuity (OR=1.01 per Early Treatment Diabetic Retinopathy Study [ETDRS] steps) became significant discriminators, respectively, observe the authors.

These latter results indicate that the sudden onset and worsening of symptoms might have been related to the vascular rupture that initiated the hemorrhage and its toxicity and organization, conclude Bek et al.

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