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Editors Selection IGR 7-1
Clinical Examination Methods: Perimetry
Comment by Donald Hood on:
*
, New York, USA 65611
Park et al. address an important clinical question: When should the clinician perform a 10-2 visual field (VF) test? As they point out, this question is timely as recent evidence suggests that macular damage occurs in early glaucoma.1,2 Further, this damage can be missed by the 24-2 VF test.1-4 To determine possible predictors of an abnormal 10-2 VF, they examined the abnormal points on the pattern standard deviation (PSD) plot of the 24-2 VF report. All eyes in their study had an abnormal appearing disc, and a 24-2 VF with a MD better than -6 dB. An abnormal 10-2 was defined based upon cluster criteria. It is worth noting that 74.7% of the eyes had abnormal 10-2 VFs, suggesting that macular damage was common in these eyes with early glaucoma.1-3
Park et al. concluded that a 10-2 test should be performed if any of the central 12 points of the 24-2 VF (i.e., those within ± 10°) are abnormal with a p < 0.5%, or with a p < 5% if located in an abnormal region of the retinal ganglion plus inner plexiform (RGC+) layer thickness map obtained from an OCT macular cube scan.
While their advice concerning 24-2 VF points with p < 0.5% is supported by their data, it is wedded to the implicit assumption that the 24-2 VF should be the gold standard for functional testing. There are alternatives. Some specialists alternate 24-2 and 10-2 VFs, even in eyes without apparent 10-2 abnormalities. Others have suggested adding some of the 10-2 VF points to the 24-2 pattern.5
Further, we agree that comparing RGC+ and VF probability plots can aid in detecting macular damage.6 However, local arcuate abnormalities and/or diffuse damage seen on RGC+ maps, and confirmed on 10-2 VFs, can be present in eyes without abnormal points on the 24-2 VF.1,2 Thus, as Park et al. imply, an OCT macular cube scan should be part of the standard OCT protocol for detecting glaucomatous damage.
References
- Hood DC, Raza AS, de Moraes CG, et al. Glaucomatous damage of the macula. Prog Retin Eye Res 2013;32:1-21.
- Hood DC, Slobodnick A, Raza AS, et al. Early glaucoma involves both deep local, and shallow widespread, retinal nerve fiber damage of the macular region. Invest Ophthalmol Vis Sci 2014;55:632-649.
- Traynis I, De Moraes CG, Raza AS, et al. Prevalence and nature of early glaucomatous defects in the central 10 degrees of the visual field. JAMA Ophthalmol 2014;132:291-297.
- Hangai M, Ikeda HO, Akagi T, Yoshimura N. Paracentral scotoma in glaucoma detected by 10-2 but not by 24-2 perimetry. Jpn J Ophthalmol 2014;58:188-196.
- Ehrlich AC, Raza AS, Ritch R, Hood DC. Modifying the conventional visual field test pattern to improve the detection of early glaucomatous defects in the central 10 degrees. Transl Vis Sci Technol 2014;3:6.
- Hood DC, Raza AS. On improving the use of OCT imaging for detecting glaucomatous damage. Brit J Ophthalmol 2014;98(Suppl 2):ii1-9.
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