Purchase this article with an account.
Sebastiao Cronemberger, Artur C Veloso, Gustavo Scarpelli, Yara C Sasso; Relationship between Intraocular Pressure (IOP) Peak and Rates of Retinal Nerve Fiber Layer (RNFL) Loss by Spectral-Domain Optical Coherence Tomography (SD-OCT). Invest. Ophthalmol. Vis. Sci. 2018;59(9):2116.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Some authors have investigated the association between average IOP and rates of RNFL change. Despite it is well-known that 24-hour peaks and IOP fluctuations have been proposed as potentially related to glaucoma damage, no paper has studied the relationship between IOP peak and rates of RNFL loss. Our purpose is to evaluate the relationship between IOP peak at 6:00 am in a 24-hour IOP and rates of RNFL thickness change over time by SD-OCT.
We analyzed the 24-hour IOP of 43 patients (43 eyes) divided into two groups: group 1 with IOP peak at 6:00 am (30 eyes) and group 2 without IOP peak (13 eyes). All patients had ophthalmologic examination, central corneal thickness (CCT) and standard automated perimetry. Each patient was submitted to a 24-hour IOP consisting of 5 IOP measurements at 9:00 am, 12:00, 6:00 and 10:00 pm with the Goldmann applanation tonometer and on the following day at 6:00 am in a supine position in bed and in darkness with Perkins tonometer before the patient had stood up. All eyes were imaged at least twice by SD-OCT (Heidelberg Engineering, Germany). For statistical analysis, we used the Student t and Chi-square tests with a level of significance <5% (P<0.05).
The group 1 had a mean age of 60.2±12.4 and group 2 of 53.3±22.8 years; P=0.35. Patients followed up for an average of 16.2±6.87 (group 1) and 17.1±6.57 months (group 2) (P=0.77). No statistically significant difference was found between groups in terms of baseline global RNFL thickness (90.4±14.7 vs. 90.8±14.5 μm; P=0.93; CCT: 527±31.1 vs. 525±31.4 μm; P=0.80; and mean IOP (13.3±2.37 vs. 13.3±1.73 mmHg; P=0.97). However, IOP at 6:00 am was consistently higher in the group 1 (19.7±3.20 vs. 14.5±2.85 mmHg; P<0.001) as well as the variance of 24-hour IOP (3.86±0.88 vs. 1.65±0.54; P<0.001). Rates of global RNFL thickness change in eyes with IOP peak were higher than in those eyes without IOP peak (-1.60±2.30 vs. 0.53±1.98 μm, respectively; P=0.005). The temporal inferior sector presented the largest association in rates of RNFL change (-2.90±4.47 vs. 2.15±3.87 μm; P=0.001)
Glaucoma patients with IOP peak at 6:00 am in 24-hour IOP had significant higher rate of global RNFL thickness change compared with those without IOP peak. More patients and longer follow-up are needed to address the degree of this relationship.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
IOP peak vs.OCT
This PDF is available to Subscribers Only