Abstract
Purpose :
To evaluate the relationship between the 24-hour intraocular pressure (DCPo) and RNFL thickness assessed by spectral-domain OCT (SD-OCT).
Methods :
Patients were submitted to an ophthalmic examination including, central corneal thickness (CCT), RNFL imaging (SD-OCT) and standard automated perimetry (SAP). We included glaucoma suspects (GS) and early POAG patients under treatment. GS were patients presenting intraocular pressure (IOP) values ranging from 19 to 24 mmHg in isolated measurements and/or cup-disc ratio>0.7 in one or both eyes and/or asymmetry of cup-disc ratio>0.3 and a normal visual field. Each DCPo was comprised of five IOP measurements with the Goldmann applanation tonometer at 9:00 am, 12:00 pm, 6:00 and 10:00 pm 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. Only the DCPos that presented an IOP peak (difference between the higher and the lesser IOP value)>6 mmHg were analyzed. In these DCPo’s, the mean IOP and the standard deviation (SD) were compared with the normal superior limits of normal patients of the same age-group. A DCPo was abnormal when the mean IOP and SD were above the normal superior limits. Visual field progression was not studied. In GS the DCPo was done for early diagnosis and in early POAG for treatment assessment. A descritive analysis was made using SPSS, version 19.0.
Results :
We included 22 eyes from 11 GS (6 male, 5 female, mean age of 61.3±14.2) and 19 eyes from 10 early POAG (1 male, 9 female, mean age of 56.7±12.0). Nine eyes of GS had cup-disc ratio equal to 0.7 and 7 eyes had cup-disc ratio equal to 0.8 . Three patients (6 eyes) had an IOP>21 mmHg. The CCT was respectively 540.2±32.2 and 529.3±32.0. All patients presented an abnormal DCPo with an IOP peak at 6 am. However, all patients had a normal SD-OCT except one GS with borderline result (figures 1/ 2). No correlation was found between IOP peak at 6 am in the DCPo and SD-OCT findings. We think that if the IOP peak is not adequately reversed, the SD-OCT might demonstrate changes over time.
Conclusions :
SD-OCT was unable to show any changes in RNFL in glaucoma suspects and early PAOG patients although they had presented IOP peaks at 6 am in bed and in darkness in the DCPo.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.