A new desktop instrument for measuring macular pigment optical density based on a novel technique for setting flicker thresholds

Abstract

A rapid portable technique for estimating macular pigment optical density (MPOD) in large populations is described. The new instrument utilises a novel method for setting flicker thresholds which is undemanding for naïve and elderly observers and easily operated by a non-technical person. The method has good repeatability (r = 0.97) and the data are comparable with an optical method based on retinal reflectometry (r = 0.78). MPOD spatial profiles are presented for seven normal observers and these are well described (r = 0.99) by a decaying exponential function consistent with previous reports. MPOD values are presented from 5581 (2435 females and 3146 males) individuals measured in 48 optometric practices. The mean MPOD of this population was 0.33 (S.D. +/- 0.187) which is similar to previous large scale studies of MP.

Measuring macular pigment optical density in vivo: a review of techniques

“…An entirely different approach to measurement of MPOD by HFP has been adopted in a new commercially available device which is described in detail by van der Veen et al [53]. Instead of the subject responding to minimal or no flicker, they respond to the appearance of flicker as the alternation rate is decreased at 6 Hz per sec from a starting level of 60 Hz.…”

“…Whilst sticking with the traditional method of HFP MPOD determination, i.e., the radiance of blue light being increased/decreased until the point of minimal flicker, it takes on a more automated approach, as per the device of van der Veen et al [53]. The instrument's electronics increase/decrease the amount of blue in the stimulus at a set rate.…”

“…Since then, HFP has been developed and used by numerous research groups investigating macular pigment. Key papers incorporating detailed descriptions and variations of the technique include Hammond and Fuld [43], Hammond et al [44], Landrum et al [45], Wooten et al [46], Beatty et al [47], Mellerio et al [48], Bone and Landrum [49], Snodderly et al [50], Tang et al [62], Iannaccone et al [51], Stringham et al [52], and van der Veen et al [53]. All other studies using HFP to measure MPOD tend to use the instruments originally designed or developed by these investigators.…”

“…BACKGROUND FIELDS Like test fields, the backgrounds upon which they are presented can also vary in size and wavelength between equipment. Sizes have ranged from 4°in diameter [e.g., 43,82] to 30° [53]. The colour of the background is invariably a blue wavelength or white.…”

“…Minimum motion photometry and apparent motion photometry [e.g., [37][38][39][40][41]. Heterochromatic flicker photometry [e.g., [42][43][44][45][46][47][48][49][50][51][52][53].…”