Date of Award

January 2016

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Ji Liu

Abstract

This study characterized the 24-hour intraocular pressure (IOP) related ocular patterns in patients with ocular hypertension (OHT) using a contact lens sensor. We aimed to identify sensor parameters unique to OHT patients, and the relationship between these parameters and disease progression to primary open-angle glaucoma (POAG). In this prospective study, 24-hour IOP-related ocular patterns were recorded by Triggerfish® (TF) contact lens sensor in 19 patients with OHT. Sensor output were used to calculate parameters including TF fluctuation, frequency of various peaks and sleep-to-wake slope. Parameters from OHT patients were compared to previously reported values in age-matched healthy and POAG eyes. Disease progression to POAG was documented by serial changes on visual fields and/or optical coherence tomography (OCT). T-test was used to compare parameters between groups. Binary logistic regression analysis was used to investigate the association between progression and parameters. We found that patients with OHT, compared to healthy controls, had significantly higher TF fluctuation (439.7 ±91.2 mV Eq vs 365.2 ±72.5 mV Eq, p=0.008) and steeper sleep-to-wake slope (-55.0 ± 55.7 mV Eq/hour vs -18.1± 41.3 mV Eq/hour, p=0.026). OHT patients had more frequent peaks than healthy controls (6.5 ± 3.6 vs 3.8 ± 1.5, p=0.005) and POAG patients (6.5 ± 3.6 vs 4.3 ± 1.2, p=0.018) in the nocturnal period. Overall, OHT patients had more frequent peaks in the diurnal than the nocturnal period (11.05 ± 3.88 vs 6.53 ± 3.56, p<0.001). More importantly, patients who converted to early POAG (79.10 ± 4.76 µm) had thinner overall retinal nerve fiber layer (RNFL) compared to the non-converter group (94.31 ± 7.55 µm, p<0.001). Converters trended towards having less peaks compared to the non-converters in the 24-hour period (13.58 ± 3.56 vs 18.75 ± 7.35, p=0.099), among other features. Nocturnal large peaks decreased the odds of conversion (adjusted OR=0.06, p=0.034) after adjusting for mean IOP in office visits, age, and pattern standard deviation on visual fields. In conclusion, OHT patients have distinct parameters in the 24-hour IOP-related ocular patterns in comparison to healthy controls and POAG patients. Large peaks in the nocturnal period decreased risk of disease progression in OHT patients. Future research is required to understand how these patterns can improve the long-term prognosis of patients with ocular hypertension.

Comments

This thesis is restricted to Yale network users only. This thesis is permanently embargoed from public release.

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