Furthermore, the ideal measuring technique should be accurate, precise (in terms of reliability and reproducibility), and allow for such results to be obtained in the appropriate study populations.
53 The Spectralis MPOD module has been shown to provide accurate and precise MP measurements in various populations.
33,54,55 In addition, studies have demonstrated that it is easy to implement in clinical practice,
9,34 where it is more likely to be applied in an ageing population, with vision loss, retinal diseases, diminished attention, and with compromised ocular media.
37 MP acquisition, as noted by Dennison et al.,
56 requires little subject compliance and takes just a few minutes to perform. Also, it has been shown that MP measurements with the Spectralis MPOD module are highly reproducible in patients with retinal pathologies, such as AMD, macular edema, and tractional maculopathy of different etiologies (i.e., diabetic maculopathy, epiretinal membrane, and macular hole).
57 Nonetheless, in these and other conditions, such as extensive geographic atrophy, dense cataracts, recent use of fluorescein intravenously or topically, advanced Stargardt disease, and others, the method fails to be accurate and hence is not appropriate to use; however, most competing techniques fail as well in these situations, so caution must be taken for all techniques. In fact, previous work has looked at the effect of cataract on MP measurement. It has been shown that high-grade cataracts cause underestimation of MP
58 at all eccentricities, including both MPOD and MPOV, using the Spectralis MPOD module. However, for research purposes, this underestimation can be corrected with different proposed correction factors in order to compare across subjects and/or studies.
58,59 Nonetheless, in clinical practice, comparisons should be done within subjects over time where each individual becomes their own control. In addition, it can be recommended that cataract be graded routinely during measurement of MP in older adults to correct for the impact of cataract on MP measurement.
59 It is our view that there is no accepted gold standard method for measuring MP.
57 And although there is no perfect measurement technique, reporting MPOV using the Spectralis MPOD module has fewer limitations than other techniques.