Assessment of microperimetry on fixation stability changes in glaucomatous eyes with hemifield defect

Background

Researches showed that microperimetry can exhibit more tiny visual function damage than conventional perimetry in glaucomatous eyes.However, the study on fixation stability of glaucoma is still rare until now.

Objective

This study was to compare the correlation between microperimetry Maia (Macular Integrity Assessment) and Humphrey perimetry, and to investigate the changes of the fixation stability in glaucoma patients with hemifield defect.

Methods

This study proposal was approved by Medical Ethic Committee of Peking University First Hospital.A cross-sectional study was performed under the informed consent of each subject.Thirty-five eyes of 35 glaucoma patients with hemifield defect by 24-2 Humphrey perimetry were included in Peking University First Hospital from December 2013 to March 2014, and 30 eyes of 30 normal volunteers served as controls.Both Humphery (10-2) and Maia (expert 10-2) were performed on the subjects respectively and the correlation of the results between Humphery (10-2) and Maia (expert 10-2) were analyzed.Then the patients with normal hemifield on Humphrey were assigned to Maia normal group and Maia abnormal group.Fixation stability differences were compared between glaucoma group and normal control group, and between Maia normal group and Maia abnormal group.

Results

The moderately positive correlation was found in the mean sensitivity between Maia microperimetry and Humphrey perimetry (r=0.403, P=0.001), and the average threshold of Maia microperimetry was moderately positive correlated with the mean defect (MD) of Humphrey perimetry in glaucoma patients (r=0.438, P=0.008). The fixation stability parameter P1 was (67±17)% and (87±10)%, and that of P2 was (70±16)% and (88±9)%; the 63% bicurve elipse area (BCEA) was (5.08±1.55)°² and (2.21±0.60)°², and the 95% BCEA was (14.74±6.04)°² and (2.86±1.17)°² in the glaucoma group and normal control group, respectively, showing significant decreases of P1 and P2 and increases of 63% BCEA and 95% BCEA in the glaucoma group compared with the normal control group (t=-5.604, -4.831, 9.885, 11.086, all at P=0.000). In Maia normal group and Maia abnormal group, the P1 was (79±8)% and (63±17)%, the P2 was (81±10)% and (67±16)%, the 63% BCEA was (3.19±0.65)°² and (5.70±1.22)°² and the 95% BCEA was (9.10±2.60)°² and (19.35±5.01)°², respectively.Compared with the Maia normal group, the P1 and P2 were significantly lower, and 63% BCEA and 95% BCEA were higher in the Maia abnormal group (t=-2.468, P=0.019; t=-2.371, P=0.024; t=5.514, P=0.000; t=5.575, P=0.000).

Conclusions

Maia microperimetry and Humphrey perimetry yield a good correlation for glaucomatous macular function examination.In addition, Maia microperimetry showed that fixation stability decreased in glaucoma patients with hemifield defect.