Abstract
Purpose :
The aim of the study was to investigate a potential association between the intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFP), in patients with open-angle glaucoma and healthy subjects.
Methods :
Fourty-three subjects were recruited (20 women and 23 men), and 86 eyes were considered; the entire group was divided according to diagnosis. Weight and height were taken into account in order to calculate the body mass index (BMI) together with blood pressure, heart rate, visual acuity, IOP, biometrics exam through IOL master to estimate the depth of the anterior chamber, corneal curvature, ocular axial length, corneal pachymetry (CCT), the thickness of the retinal nerve fiber layer and macular thickness papillary through optical coherence tomography (OCT optovue RTVue). Visual field examination (Humphrey Sita Standard 24-2) was carried out on all the patients and the pattern standard deviation (PSD) and the mean deviation (MD) were considered.
Cerebrospinal fluid pressure (CSFP) was estimated indirectly by using the mathematical formula CSFP = 0.44 x BMI + 0.16 x diastolic pressure - 0.18 x age -1.91 based on previous scientific studies. Furthermore the trans-lamina cribrosa pressure difference (TLCPD) was calculated as: IOP - estimated CSFP.
Results :
The t Student test showed a significant (p<0.05) difference between the two groups for several parameters. The CSFP was lower in patients with POAG then in healthy subjects (7.43 +/- 2,06 and 8.14+/- 4.52, p<0.001 respectively), while the TLCPD was significantly higher in glaucomatous patients than in healthy subjects (8.42 +/- 3.27 and 6.23 +/- 4,14, respectively). A significantly correlation was found between TLCPD and both RNFL thickness and mean deviation.
Conclusions :
The CSFP is lower whereas the TLCPD is higher in glaucomatous patients compared to healthy subjects. Therefore a high TLCPD could lead to RNFL suffering resulting in functional impairment detectable in a visual field. These findings also support the hypothesis that the CSFP may play a role in the pathogenesis of glaucomatous optic neuropathy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.