February 2019

INTERNATIONAL

Presentation spotlight
24-hour ocular dimensional profile sheds light on ‘unexplained’ glaucoma progression


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer


Dr. Cutolo used a contact lens sensor to record IOP for a 24-hour period and was able to link specific pressure-related parameters with visual field progression.
Source: Carlo Cutolo, MD

“This device could potentially be used to assess treatment efficacy of IOP lowering interventions in clinical practice and help assess clinical results.”
—Carlo Cutolo, MD

 

Researchers think a contact lens sensor has potential in the assessment of treatment efficacy of IOP lowering interventions

Daytime intraocular pressure (IOP) measurements have long been questioned for their accuracy in reflecting the actual highs and lows of a glaucoma patient’s IOP. Patients with well-controlled daytime pressures, as measured at the doctor’s office, will often develop signs of glaucoma progression with visual field defects. IOP is a modifiable glaucoma risk factor known to fluctuate during the course of the day, and therefore, assessing the extent of this fluctuation could be instrumental in helping to guide clinical management in individuals with glaucoma.
According to an e-poster presented at the 36th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS) by Carlo Cutolo, MD, Genova, Italy, and co-authors, many glaucoma patients progress and lose valuable eye sight, even those with apparently low IOP measurements. He thinks that the 24-hour variability in IOP may explain optic nerve vulnerability better than IOP measured during office hours.
“Many glaucoma patients experience visual field deterioration despite intraocular pressure measurements within normal limits during office hours,” Dr. Cutolo said. “Parameters derived from a contact lens based system [CLS, Sensimed Triggerfish, Lausanne, Switzerland] have recently been shown to correlate better with visual field progression than office hour Goldmann applanation tonometry (GAT).1,2 In this study, we investigated the effect of different IOP lowering interventions on CLS parameters and their relationship with GAT-measured IOP reduction.”

Study design

Thirty centers from 16 countries were involved in this prospective investigation that tested the hypothesis that the contact lens sensor device can objectively measure treatment effects in glaucoma patients undergoing different types of IOP-lowering interventions. The study set out to determine which type of intervention had the strongest effect on 24-hour ocular dimensional patterns related to IOP.
One hundred and eighty-two eyes of 182 patients were included in the study in which the 24-hour ocular dimensional profile was recorded in one eye/patient via CLS both before and after IOP lowering interventions. The interventions implemented included topical pressure lowering medications in 60 eyes, laser trabeculoplasty in 69 eyes, and incisional surgery in 53 eyes.
A set of 115 different CLS parameters were investigated from the 24-hour recordings. Dr. Cutolo compared before versus after values for each parameter. The average time between measurements was 66±53 days. In addition, linear regression was performed using the percentage change of each CLS parameter as the outcome variable and the type of IOP lowering procedure as the predictor after adjusting for age and race. Finally, the study investigated the relationship between changes in CLS parameters and GAT IOP with Pearson’s correlations. The Benjamini-Hochberg approach was used to adjust for multiple tests.
Open angle glaucoma patients, ocular hypertensives, and glaucoma suspects underwent a 24-hour CLS and were included in the study provided their CLS readings were sufficient and reliable. Patients with incomplete or insufficient CLS recordings were excluded from the study.

Study outcomes

All three interventions were effective in reducing IOP in the study participants, to varying degrees. The mean IOP measured in the incisional surgery patient group prior to the intervention was 21.4 mm Hg, which was reduced by a mean –6.8 mm Hg (95% CI –9.3 to –4.2) to a mean 14.7 mm Hg after the intervention. In the trabeculoplasty group, IOP went from a mean 17.2 mm Hg before to 14.6 mm Hg after the intervention, reflecting a reduction of –2.7 mm Hg (95% CI –3.6 to –1.7). IOP in the group treated with topical medications was 18.1 mm Hg before and 17.1 mm Hg after drug administration, which was a change in pressure of –0.97 mm Hg (95% CI –2.1 to 0.18).
The linear regression analysis revealed that for 23 CLS parameters, incisional surgery was significantly more effective than the other two interventions. Surgery was most predictive for the greatest percentage of change in CLS signals. For one CLS parameter, laser trabeculoplasty was shown to be significantly more effective than topical medications.
“Incisional glaucoma surgery had a more pronounced effect on GAT and the 24-hour CLS parameters than both laser trabeculoplasty and drugs. Surgery > laser = drugs. Compliance is less of an issue after surgery,” Dr. Cutolo said. “The CLS can detect changes in patterns resulting from IOP lowering interventions beyond daytime GAT IOP, and this device could potentially be used to assess treatment efficacy of IOP lowering interventions in clinical practice and help assess clinical results. Nocturnal CLS patterns were most sensitive to all types of interventions.”
According to previously published study outcomes by De Moraes et al. that included 445 treated glaucoma patients who underwent 24-hour CLS, visual field progression correlated with CLS recordings. The number of long peaks during sleep and the mean peak ratio when patients were awake were the best predictors of faster progression. The combination of CLS parameters provided better measures than Goldmann applanation IOP parameters (mean, peak, fluctuation) in the same period.2
In an unrelated trial, investigators found the Triggerfish CLS to be safe and well tolerated for monitoring IOP-related patterns and an option that could expand the IOP information available to clinicians. They think the information obtained could have important applications in identifying high risk patients and monitoring the response to treatment interventions.3

References

1. De Moraes CG, et al. Visual field change and 24-hour IOP-related profile with a contact lens sensor in treated glaucoma patients. Ophthalmology. 2016;123:744–53.
2. De Moraes CG, et al. Association between 24-hour intraocular pressure monitored with contact lens sensor and visual field progression in older adults with glaucoma. JAMA Ophthalmol. 2018;136:779–785.
3. Dunbar GE, et al. The Sensimed Triggerfish contact lens sensor: efficacy, safety, and patient perspectives. Clin Ophthalmol. 2017;11:875–882.

Editors’ note: Dr. Cutolo has financial interests with Sensimed.

Contact information

Cutolo: carloalberto.cutolo@edu.unige.it

24-hour ocular dimensional profile sheds light on ‘unexplained’ glaucoma progression 24-hour ocular dimensional profile sheds light on ‘unexplained’ glaucoma progression
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