Microperimetry may be a more sensitive method of detecting a small glaucomatous defect close to fixation, than standard automated perimetry and OCT analysis of the retinal nerve fibre layer (RNFL)

The Science behind the Tip

Microperimetry is a form of fundus-tracking perimetry that can detect reduced retinal sensitivity close to fixation more effectively the standard automated perimetry (SAP) (1,2). This can be useful in patients with focal ischaemic glaucoma where a subtle localised defect is commonly found close to fixation early in the clinical course. This has been previously evaluated using OCT of the RNFL (3).

In a recent study of patients with presumed monocular focal ischaemic glaucoma and a normal visual field in the fellow eye measured using SAP, microperimetry detected a focal defect (81%) more effectively than OCT (54%) (4).

In these circumstances, treatment can be instituted at early stage to reduce the risk of bilateral scotomas close to fixation.

Contributor: John F Salmon MD - Oxford Eye Hospital - UK

References

1. Rao HL, Januwada M, Hussain RS et al. Comparing the structure-function relationship at the macula with standard automated perimetry and microperimetry. Invest Ophthalmol Vis Sci 2015; 56: 8063-8

2. Lima VC, Prata TS, De Moraes CG et al. A comparison between microperimetry and standard achromatic perimetry of the central visual field in eyes with glaucomatous paracentral visual field defects. Br J Ophthalmol 2010; 94: 64-7

3. Sato S, Hirooka K, Baba T et al. Correlation between the ganglion cell-inner plexiform layer thickness measured with cirrus HD-OCT and macular visual field sensitivity measured with microperimetry. Invest Ophthalmol Vis Sci 2013; 54: 3046-51

4. Yusuf I, Jolly JK, Ratnarajan G, Salmon JF. Microperimetry and ocular coherence tomography imaging in the fellow eye of pateints with unilateral focal ischaemic glaucoma. Eye 2018; 32:1372-79

Tip Reviewer: Roger Hitchings
Tip Editor: John Salmon