Ocular Hemodynamics Research Of Optic Nerve Damage In Glaucoma

As one of the major causes of blindness in the world, glaucoma is amultifactorial optic neuropathy characterized by loss of retinal nerve fibers, structuralchanges to the optic nerve, and an associated change in visual function. Althoughintraocular pressure is a well-known risk factor for glaucomatous optic neuropathy, itis not the only one. The ocular ischemic change may be another important factor inthe development and progression of this disease. As the main treatments of glaucoma,drug, laser or surgery, are all with intraocular pressure-lowering as goals of treatment.The role of ocular hemodynamics changes in glaucoma optic neuropathy isparticularly critical for those glaucoma patients with well-controlled intraocularpressure but progressive visual functional damage. Most studies on hemodynamicsare restricted to measurement at a single time point, but with no long-term dynamicobservation.2-year follow-up observations on ocular hemodynamics were performedin some glaucoma patients with normal intraocular pressure after treatment with drugs,laser or surgery. These studies are to analyze the role of ocular hemodynamicschanges on optic nerve damage in glaucoma patients, and help to provide guidance forclinical treatment.68eyes of34glaucoma patients, male22and female12, treated in the FirstHospital of Jilin university from January2009to January2012were included overtwo year time frame. All the subjects aged61to87.15healthy controls matched forage, sex, and intraocular pressure (between10and21mmHg) were included. All thesubjects underwent24-hour intraocular pressure measurements, ultrasoundbiomicroscope(UBM), optical coherence tomography（OCT）and color doppler flowimaging（CDFI) of the ophthalmic artery (OA), the central retinal artery（CRA）andthe short posterior ciliary arteries（SPCA）. The above observation indicators werereviewed half a year in the following two years. The data was evaluated at initialinspection,1-year and2-year after selected. All of the statistical analyses were performed with SPSS17.0software.Clinical observations showed that the blood flow in OA, CRA and SPCA in allpatients was significantly decreased and RI was increased compared with the normalcontrol group during the2-year follow-up period. The t values of PSV in OA at eachobservation point were2.91、3.69、3.84, that of EDV were3.53、5.04、5.81, and thatof RI were1.45、2.89、2.60respectively (p <0.05). The same variation tendency wasfound in CRA and SPCA. There was no significant difference in the longitudinalobservation of OA hemodynamics in glaucoma patients compared with the controlgroup. Some changes on MD、PSD values and mean RNFL thickness were observed,there was no statistically significant difference between two group, however. One-wayanalysis of variance was used to analyze the effects of diabetes and hypertension onocular blood flow, showing that hypertension and diabetes influenced OA blood flowgreatly.Our results showed that ocular blood flow velocities were significantly lower inglaucoma patients than that in control group. However, no statistically significantcorrelation was observed between the ocular hemodynamics and the optic nervedamage due to the limited follow-up period and small sample size in current study. Insome glaucoma patients, disease progression can occur despite adequate IOP control,it is therefore improving ocular perfusion should be considered for the treatments forglaucoma patients to protect their visual function. Further studies are warranted toelucidate the precise relationship between optic nerve damage and ocularhemodynamics alteration.