Abstract
Purpose:
To determine if neuroretinal function differs in normal adult males and females under and over the age of 50 years, and whether aging patterns of neuroretinal function differ in the sexes.
Methods:
One eye from each of 50 healthy subjects (age range 24 to 61 years, 29 females and 21 males) was included in this study. Neuroretinal function was assessed using first-order P1 implicit times (IT) and N1-P1 amplitudes (AMP) from photopic multifocal electroretinograms (mfERG). Comparisons of IT or AMP were made using whole eye averages, frequency of abnormalities, and response topographies. Whole eye averages were calculated by averaging each subject’s 103 ITs and (separately) AMPs. IT and AMP abnormalities were defined as any Z-score ≥2 or Z-score ≤-2, respectively. Response topographies were constructed by averaging IT or AMP at each of the 103 stimulated locations for each subject group, and analyzed by comparing corresponding locations of another group using 95% confidence intervals.
Results:
In subjects <50 years old (y.o.), females had superior neuroretinal function compared to males: 80.6% of their response topography locations were significantly faster, and their whole eye IT averages were shorter (P=0.015). In contrast, neuroretinal function was similar in males and females >50 y.o. Almost all IT abnormalities in the females (66/70=94.3%) occurred in those who had reported a hysterectomy (n=5). This subset of females had the longest whole eye ITs of any group (P<0.002). In the females >50 y.o. who did not report a hysterectomy, neuroretinal function was worse compared to the females <50 y.o.: 60.2% of their response topography locations were significantly slower, and whole eye IT averages were longer (P=0.04). Conversely, neuroretinal function in the males <50 y.o. and the males > 50 y.o. was similar. Unlike the IT results, AMP abnormalities were not associated with hysterectomies, and no significant AMP differences (whole eye, frequency of abnormalities, or response topography) were found between the females <50 y.o. and the males <50 y.o.
Conclusions:
Retinal function measured by mfERG IT differs in the sexes depending on age group and hysterectomy status. MfERG IT, but not mfERG AMP, appears to parallel predicted levels of estrogen in males and females.
Keywords: 509 electroretinography: clinical •
695 retinal degenerations: cell biology •
688 retina