Reference Clinical Database for Fixation Stability Metrics in Normal Subjects Measured with the MAIA Microperimeter

Abstract

PurposeThe purpose of this study was to establish a normal reference database for fixation stability measured with the bivariate contour ellipse area (BCEA) in the Macular Integrity Assessment (MAIA) microperimeter.MethodsSubjects were 358 healthy volunteers who had the MAIA examination. Fixation stability was assessed using two BCEA fixation indices (63% and 95% proportional values) and the percentage of fixation points within 1° and 2° from the fovea (P1 and P2). Statistical analysis was performed with linear regression and Pearson's product moment correlation coefficient.ResultsAverage areas of 0.80 deg2 (min = 0.03, max = 3.90, SD = 0.68) for the index BCEA@63% and 2.40 deg2 (min = 0.20, max = 11.70, SD = 2.04) for the index BCEA@95% were found. The average values of P1 and P2 were 95% (min = 76, max = 100, SD = 5.31) and 99% (min = 91, max = 100, SD = 1.42), respectively. The Pearson's product moment test showed an almost perfect correlation index, r = 0.999, between BCEA@63% and BCEA@95%. Index P1 showed a very strong correlation with BCEA@63%, r = −0.924, as well as with BCEA@95%, r = −0.925. Index P2 demonstrated a slightly lower correlation with both BCEA@63% and BCEA@95%, r = −0.874 and −0.875, respectively.ConclusionsThe single parameter of the BCEA@95% may be taken as accurately reporting fixation stability and serves as a reference database of normal subjects with a cutoff area of 2.40 ± 2.04 deg2 in MAIA microperimeter.Translational RelevanceFixation stability can be measured with different indices. This study originates reference fixation values for the MAIA using a single fixation index.

Retinal Sensitivity and Fixation Stability Changes during Repeated Microperimetry

“…Rohrschneider et al [3], Weingessel et al [4], and Morales et al [21,22] found a decrease in fixation stability with an increasing age in normal subjects, and older observers showed greater variability in their fixations. Age might be a significant factor for fixation loss, but microperimetry is a psychophysical test; thus, it might present a learning effect for fixation stability.…”

“…With microperimetry biofeedback training, patients with macular diseases who have lost foveal fixation capabilities are trained to relocate their preferred retinal locus (PRL) into an area with better sensitivity. This training to relocate the PRL can improve the fixation behavior and, thereby, visual performance [21][22][23]24,25]. Several authors have demonstrated that this training is effective in patients with loss of central vision secondary to macular pathologies, particularly in cases with geographic atrophy secondary to AMD [21,23,24,26]; however, it has also been reported that patients with macular disease may use two or more PRLs for fixation [24,25,27].…”

Microperimetry for geographic atrophy secondary to age-related macular degeneration

“…There are several commercially available microperimetry devices, all with defining features that potentially drive one to be the instrument of choice over others. The key differences are range of stimulus intensity (0e20 dB to 0e50 dB), eye-tracker frequency (8e30 Hz), 28 background illumination (1.27 cd/m 2 e10 cd/m 2 ), and imaging features (color fundus photography, scanning laser ophthalmoscope, OCT) (Table). 15,26 Different features may be better suited to answering different questions; for example, imaging frequency, which is not necessarily the rate-defining step for technical stimulus placement or adjustment, may not be as important for consideration as dynamic range of the stimulus intensity.…”

To BCVA, or not to BCVA, that is the question

“…Most studies of the MAIA have used one of two available test methods: a 68‐point test that is similar to the 10–2 programme of the Humphrey Field Analyser, or the so‐called Standard test that examines 37 points within the central 10 degrees. The 37‐point test takes about 6 min per eye …”

“…The Nidek MP3 also does this. The MAIA additionally reports the area of the ellipse enclosing the fixational jitter and rates the fixation error as: ‘stable, relatively unstable, or unstable’ …”