Prevalence and type of artefact with spectral domain optical coherence tomography macular ganglion cell imaging in glaucoma surveillance

PURPOSE:The ganglion cell analysis (GCA) of the CIRRUSTM HD-OCT (Carl Zeiss, Meditec; Dublin, CA) provides measurement of the macular ganglion cell-inner plexiform layer (GCIPL) thickness. This study determined the frequency of scan artefacts and errors in GCIPL imaging in individuals undergoing HD-OCT surveillance for glaucoma. METHOD:A total of 1439 eyes from 721 subjects enrolled in a prospective study assessing predictors of glaucoma progression underwent macular GCIPL imaging with the CIRRUS HD-OCT at recruitment. The prevalence of acquisition errors, segmentation errors, and co-morbid macular pathology was determined. RESULTS:A total of 87 (6.0%) of the 1439 scans had either acquisition errors, segmentation artefacts, or other macular pathology. The most common co-morbid macular pathology was epiretinal membrane in 2.2% of eyes. CONCLUSION:The macular GCIPL scan was artefact free in 94% of eyes. However, epiretinal membrane and high myopia can cause scan artefact and should be considered when interpreting the results.Mona S. Awadalla, Jude Fitzgerald, Nicholas H. Andrew, Tiger Zhou, Henry Marshall, Ayub Qassim, Mark Hassall, Robert J. Casson, Stuart L. Graham, Paul R. Healey, Ashish Agar, Anna Galanopoulos, Simon Phipps, Angela Chappell, John Landers, Jamie E. Crai

Abnormal autonomic responses to laboratory challenges and their clinical relevance in POAG and NTG.

<p>Abnormal autonomic responses to laboratory challenges and their clinical relevance in POAG and NTG.</p

Correlation between glaucoma severity and autonomic response.

<p>Correlation between glaucoma severity and autonomic response.</p

Group comparison of HRV parameter changes to meal ingestion.

<p><b>A, B, C</b> shows, in supine position, from pre-ingestion to early after meal ingestion (30min postprandially), HRV parameters’ changes are different in POAG, compared to NTG and Control. There are reductions in HRV LF power nu and HRV LF/HF ratio, and an increase in HRV HF power nu in POAG. <b>D, E, F</b> shows, in standing position, from fasting to 90 minutes after carbohydrate ingestion (maximal response), HRV parameters’ changes are different in NTG, compared to POAG and Control. There is an increase in HRV LF power nu and a decrease in HRV HF power nu in NTG. § <i>P</i>< 0.05, §§ <i>P</i>< 0.01, NTG vs POAG; <i>P</i>< 0.05, Control vs POAG; ¥ <i>P</i>< 0.05, Control vs NTG; data shown as Mean ± SEM.</p

Hemodynamic responses at 60, 90 and 120 minutes following carbohydrate ingestion.

<p>Following carbohydrate ingestion, in the later phase of postprandial state, MAP maintained stable and HR increased in all three groups. In response to postural stress (from supine (○) to standing (▲)), MAP increased in control and PAOG, but not in NTG. HR increased in all three groups. *P<0.05, ** P<0.01; data shown as Mean ± SEM.</p

Autonomic changes in response to carbohydrate ingestion and postural stress (glaucoma N = 37 vs controls N = 36).

<p>From fasting (0 min) to postprandial state (30, 60, 90, 120 min), HRV LF nu increased, HRV HF nu decreased, and HRV LF/HF increased in glaucoma patients; whereas HRV parameters remained unaltered in controls, albeit an increase in HRV LF nu. SBP LF power increased and BRS reduced in both glaucoma and control subjects. (*P<0.05, **P<0.01, effect of carbohydrate ingestion; two-way ANOVA). From supine (○) to standing (▲) position, SBP LF power, BRS and all HRV parameters showed comparable changes in glaucoma and control groups. (*P< 0.05, **P<0.01, effect of postural change before and after carbohydrate ingestion; two-way ANOVA).</p

Subjects’ general profiles.

<p>Subjects’ general profiles.</p

Subjects’ glaucoma severity.

<p>Subjects’ glaucoma severity.</p

Hemodynamic responses 30 minutes following carbohydrate ingestion.

<p>MAP fell 30min after meal ingestion in POAG, whereas MAP maintained stable in control and NTG subjects. HR increased 30min after eating in all three groups. HR also increased in response to postural stress, i.e., from supine (○) to standing (▲).** P<0.01; data shown as Mean ± SEM.</p

Baseline (pre-ingestion) hemodynamic and autonomic data.

<p>Baseline (pre-ingestion) hemodynamic and autonomic data.</p