The effects of antioxidants on ocular blood flow in patients with glaucoma.

PURPOSE: To investigate the effects of an antioxidant dietary supplement that includes Ginkgo biloba, on retinal and retrobulbar blood flow in patients with open-angle glaucoma (OAG). METHODS: Forty-five patients with confirmed OAG were enroled in a randomized, double blinded, placebo-controlled cross-over study. Baseline and postadministration measurements of intraocular pressure (IOP), ocular perfusion pressure (OPP), retrobulbar blood flow, and retinal capillary blood flow were non-invasively measured (ultrasound and laser Doppler modalities, respectively) before and one month after antioxidant nutraceuticals and placebo administration. Changes in measurements between the active supplement and placebo arms were evaluated using paired t-tests, with p < 0.05 considered statistically significant. RESULTS: Antioxidant supplementation produced a statistically significant increase in peak systolic and/or end diastolic blood flow velocities in all retrobulbar blood vessels compared to placebo. Vascular resistance was also reduced in central retinal and nasal short posterior ciliary arteries following antioxidant administration. Additionally, antioxidant supplementation increased superior and inferior temporal retinal capillary mean blood flow and the ratio of active to non-active retina capillaries compared to placebo. CONCLUSION: One-month oral administration of antioxidants produced increases in biomarkers of ocular blood flow within retinal and retrobulbar vascular beds in patients with OAG.

[Efficacy on visual display terminal syndrome treated with jingjin therapy of Zhuang medicine].

OBJECTIVE: To observe the efficacy and explore the effect mechanism on visual display terminal syndrome treated with jingjin therapy of Zhuang medicine. METHODS: Sixty-five patients of visual fatigue induced by the visual display terminal operation were treated with jingjin trigeminy therapy of Zhuang medicine, e.g. massage manipulation, acupuncture and cupping; acting on the specific stimulating areas in Zhuang medicine, relevant with orbit, temple, forehead, ear and Baihui (GV 20). Each treatment lasted 40 min, once every two or three days. Totally, 10 to 14 treatments were required. The scores of visual symptoms and the ocular hemodynamics before and after treatment were observed, and clinical effect were evaluated in the two groups. RESULTS: After treatment, the scores of visual symptoms were reduced apparently as compared with those before treatment (all P<0.05). The total effective rate was 84.6% (55/65). The peak systolic velocity (PSV), the end diastolic velocity (EDV) in anterior ciliary artery (ACA) and the central retinal artery (CRA) were improved obviously, indicating the significant differences before and after treatment (all P<0.05). CONCLUSIONS: The jingjin therapy of Zhuang medicine alleviates the visual symptoms in patients of visual fatigue and improves visual quality. The effects are related to the improvement of ocular microcirculation.

Effects of sub-Tenon's anaesthesia on ocular hemodynamics.

OBJECTIVE: To research the effects of sub-Tenon's anaesthesia (STA) on ocular hemodynamics in patients with cataract using colour Doppler imaging (CDI). DESIGN: Prospective clinical study. PARTICIPANTS: Thirty-four eyes of 34 patients with age-related cataract. METHODS: Peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) values of the ophthalmic artery (OA), central retinal artery, and central retinal vein were measured by CDI before and immediately after performing sub-Tenon block using 2 mL of 2% lidocaine with adrenaline (1:200 000). RESULTS: Both PSV and EDV values were significantly decreased after sub-Tenon injection in all the studied vessels of the patients. However, no important changes were observed in the RI values of the vessels. CONCLUSIONS: STA markedly reduced ocular blood flow. The reduction may be more acceptable compared with other retrobulbar block methods. Sub-Tenon block should be performed carefully to senile patients with cataract with vascular occlusive disorder.

[Physiological mechanism for the regulation of ocular circulation].

Ocular circulation is regulated to maintain the homeostasis of retinal function in response to physiological stimulus. It is important to understand the mechanism of the regulation of ocular circulation under physiological conditions because the impairment of ocular circulation should cause severe retinal disorders. We previously investigated the physiological mechanism of ocular circulation in response to hypoxia, hypercapnia, and acute increased systemic blood pressure. In addition, it was reported that transpupillary thermotherapy might change ocular blood flow in patients with age-related macular degeneration. However, it still remains unclear whether the increased ocular tissue temperature may be associated with alteration of the ocular blood flow. Therefore, we examined the effect of ocular warming on retinal blood flow (RBF) and subfoveal choroidal blood flow (CBF) in humans. Ocular warming was induced in 10 healthy volunteers using an ocular warming lamp for 10 minutes. The RBF in the retinal artery and vein and the CBF in the foveal region were examined with a retinal laser Doppler velocimetry system and a laser Doppler flowmeter, respectively. Ocular warming increased RBF in the retinal artery and vein but decreased CBF in the foveal region. The CBF in the foveal region may contribute to maintaining a constant retinal temperature in response to ocular warming.

[The effect of retrobulbar injection with anisodamine on ocular blood velocity in anterior ischemic optic neuropathy].

OBJECTIVE: To study the effect of retrobulbar injection with anisodamine on ocular blood velocity in anterior ischemic optic neuropathy (AION). METHODS: 15 minutes before injection, 15 minutes and 1 hour after injection, the blood flow velocity in 39 cases (39 eyes) diagnosed as AION was measured and analyzed by CDI, timed average maximum velocity, peak systolic velocity, end diastolic velocity, resistance index and pulsatility index of OA, CRA and PCA were recorded. RESULTS: Compared with the normal eyes, each parameter of SPCA was statistically significant. 15 minutes and 1 hour after post ocular injection of anisodamine, every parameter examined in the experiment was increased except resistance index compared with pre-injection (P < 0.01). CONCLUSIONS: retrobulbar injection with anisodamine can effectively improve flow velocity of nasal and tempo short posterior ciliary artery and central retinal artery.

Influence of infusion volume on the ocular hemodynamic effects of peribulbar anesthesia.

PURPOSE: To test the hypothesis that ocular blood-flow response to peribulbar anesthesia can be reduced by using a smaller volume of anesthetic mixture. SETTING: Departments of Ophthalmology and Clinical Pharmacology, Medical University of Vienna, Vienna, Austria. METHODS: Twenty patients scheduled for bilateral age-related cataract surgery were enrolled in a prospective randomized balanced observer-masked crossover study. Two study days with a 2 mL injection volume or 5 mL injection volume used for peribulbar anesthesia were scheduled. On 1 study day, patients received the 1-dose regimen and on the other study day, when the contralateral eye had surgery, patients received the other injection volume. On both study days, the anesthetic mixture consisted of an equal amount of lidocaine, bupivacaine, and hyaluronidase independently of the injection volume. Intraocular pressure (IOP), blood pressure, and pulse rate were measured noninvasively. Ocular fundus pulsation amplitude (FPA) and peak systolic and end diastolic flow velocities in the central retinal artery were measured with laser interferometry and color Doppler imaging, respectively. The results were recorded as means +/- SD. RESULTS: Peribulbar anesthesia increased IOP and reduced FPA and flow velocities in the central retinal artery. The effects on IOP (5 mL, 35.1% +/- 16.0%; 2 mL, 14.1% +/- 14.1%; P<.001) and ocular hemodynamic parameters (FPA: 5 mL, -17.5% +/- 7.8%/2 mL, -7.3% +/- 7.2%, P<.001; peak systolic velocity: 5 mL, -19.5% +/- 10.7%/2 mL, -10.6% +/- 9.8%, P = .013; end diastolic velocity: 5 mL, -16.7% +/- 6.2%/2 mL, -8.4% +/- 7.3%, P = .005) were more pronounced with the 5 mL injection volume than with the 2 mL injection volume. CONCLUSIONS: An injection volume of 2 mL instead of 5 mL reduced the ocular blood-flow response to peribulbar anesthesia. This procedure may be used in patients with ocular vascular disease to reduce the incidence of anesthesia-induced ischemia and loss of vision.

Effects of electroacupuncture on retinal nerve growth factor and brain-derived neurotrophic factor expression in a rat model of retinitis pigmentosa.

The aim of this study was to investigate the effect of electroacupuncture (EA) on the progression of retinal degeneration in rats affected by inherited retinitis pigmentosa (IRP) and to correlate this event with the retinal expression of neurotrophins. Thirty-day-old Royal College of Surgeons (RCS) rats were exposed to 25-min-long daily sessions of low-frequency EA for 11 consecutive days. Control-untreated and EA-treated rats were sacrificed 1 h after the last EA session, and their retina removed for biochemical, molecular, and immunohistochemical analyses. Our data revealed that daily sessions of low-frequency EA for 11 days to RCS rats during a critical developmental stage of retinal cell degeneration cause an increase of retinal nerve growth factor (NGF) and NGF high-affinity receptor (TrkA) expression; and increase of outer nuclear layer (ONL) thickness; and enhanced vascularization. These findings suggest the possible beneficial effects of EA treatment in the development of IRP-like retinal degeneration of RCS rats and that the mechanism through which EA might exerts its action on the regulation of NGF and brain-derived neurotrophic factor (BDNF) and/or their receptors in retinal cells.

Colour Doppler imaging before and after retrobulbar anaesthesia in patients undergoing cataract surgery.

PURPOSE: To investigate the effect of retrobulbar anaesthesia on retrobulbar haemodynamics, colour Doppler imaging was performed. Furthermore, the additive effect of epinephrine was examined. METHOD: Forty-one patients (age 72.7+/-8.9; 22 f, 19 m) undergoing planned cataract surgery were included in a prospective study. Colour Doppler imaging was performed before and directly after retrobulbar anaesthesia and after cataract surgery to measure the peak systolic velocity (PSV) and end-diastolic velocity (EDV) in the ophthalmic artery, central retinal artery and central retinal vein. In 18 patients lidocaine 2% without additives (2 ml, retrobulbar transconjunctival injection) and in 23 patients lidocaine 2% with epinephrine 1:200,000 was used. RESULTS: After retrobulbar anaesthesia both groups had a significant reduction of the PSV and of the EDV. After surgery flow velocities increased again. The addition of epinephrine resulted in a significantly greater reduction and slower recovery of flow velocities. CONCLUSION: Retrobulbar anaesthesia induces a marked reduction of velocity in the retrobulbar vessels. The supplement epinephrine increases this effect, and recovery is much slower. Thus, particularly in patients with already disturbed ocular haemodynamics epinephrine should not be used in order to avoid irreversible functional damage.

Effects of hachimi-jio-gan (ba-wei-di-huang-wan) on blood flow in the human central retinal artery.

Hachimi-jio-gan (HJG), a Chinese herbal formula, and a placebo were given to 12 healthy adults, and the changes in blood flow in the central retinal artery were observed with the latest ultrasonic diagnosis device before and after administration. After administration of HJG, the systolic flow velocity, diastolic flow velocity and mean flow velocity in the central retinal artery showed significant increases. No change was observed in vascular resistance. The subjects deemed suitable for use of HJG showed remarkable increases in blood flow. No changes in blood flow velocities and vascular resistance were observed after administration of the placebo. HJG is frequently used in the aged, often with eye diseases such as cataract. It has been reported that a decrease of blood flow in the central retinal artery becomes more marked in proportion to the progress of various eye diseases. As increases in blood flow were obvious in the cases that were treated with HJG, it is suggested that increases in blood flow in the central retinal artery due to HJG give direct evidence supporting the positive effects of HJG on eye diseases.

Ocular massage in a case of central retinal artery occlusion the successful treatment of a hitherto undescribed type of embolism.

BACKGROUND: The pathogenesis of central retinal artery occlusions (CRAO) varies, depending upon the underlying disease. An embolic origin of an occlusion often occurs. PATIENT AND METHODS: A 50-year-old man with an occlusion of the left internal carotid artery was examined because of a left central retinal artery occlusion. Fluorescein angiography revealed that in no blood vessel could any circulation of blood be demonstrated. The slight vascular filling with dye mainly came from collateral circulation at the disc. RESULTS: Ocular massage was carried out. After a delay of several minutes, the vessels of the fundus became increasingly filled with blood. The patient noticed continuing recovery in the vision of his left eye. During fluorescein angiography, carried out one day later, white embolic clots appeared in the arteries of the papilla, some of them moving with the velocity of the blood flow through the retinal vessels and reaching the periphery of the retina and immediately disappearing. Others moved more slowly. This was seen repeatedly over several minutes. CONCLUSIONS: In this patient we have recorded in a fluorescein angiogram bright boluses visible in the blood of the retinal arteries. We suggest that conglomerations of blood cells can also cause an obstruction of blood flow. The observation of this kind of bright clots (boluses) visible in the blood of the retinal arteries we did not find described in the literature. In such a situation ocular massage is extremely helpful. Therefore, ocular massage should be carried out in every patient with CRAO.

Effects of peribulbar anesthesia on ocular blood flow in patients undergoing cataract surgery.

PURPOSE: The effects of extraconal, peribulbar anesthesia on ocular blood flow may be caused by concomitant elevations in intraocular pressure or direct pharmacologic alteration of vascular tone. We quantified the effect on ocular circulation with a new technique for assessment of ocular hemodynamics. METHODS: In a prospective study, ocular hemodynamics were measured before and 1 and 5 minutes after peribulbar anesthesia in 22 eyes with age-related cataract. Measurements included fundus pulsation amplitude with a laser interferometric method assessing the pulsatile choroidal blood flow and mean blood flow velocity as well as resistive index in the ophthalmic and central retinal artery with Doppler sonography. Systemic blood pressure and pulse were monitored throughout the period of ocular hemodynamic measurements. RESULTS: Fundus pulsation amplitude decreased significantly after peribulbar anesthesia (after 1 minute and 5 minutes: -13% and -8%; P < .001). In the central retinal artery, mean blood flow velocity dropped (-15%; P < .001) and resistive index increased (+3%; P = .02) 1 minute after peribulbar anesthesia compared with baseline. There were no changes in ophthalmic artery hemodynamics. Intraocular pressure was elevated 1 minute after peribulbar anesthesia (+29%; P = .003) but reached baseline values after 5 minutes. CONCLUSION: Pulsatile choroidal blood flow and retinal blood flow velocities were reduced after peribulbar anesthesia. These reductions were still present 5 minutes after peribulbar anesthesia, when intraocular pressure had returned to baseline values. This supports the theory of drug-induced vasoconstriction after peribulbar anesthesia. A loss of vision may be a risk of peribulbar anesthesia in patients who have compromised ocular blood flow before surgery.

Hemodynamic and visual function effects of oral nifedipine in patients with normal-tension glaucoma.

PURPOSE: To investigate ocular hemodynamic and visual function changes in patients with normal-tension glaucoma after treatment with a calcium channel blocker (nifedipine). METHODS: In 21 patients with normal-tension glaucoma, color Doppler imaging of the ophthalmic, central retinal, and short posterior ciliary arteries was carried out after a 4-week washout of prior drug treatment and again after 6 months of treatment with nifedipine (30 mg per day). Visual field sensitivity, spatial contrast sensitivity, and intraocular pressure were also recorded. RESULTS: Three subjects experienced intolerable side effects from the drug and were removed from the study. In two other patients, visual function was substantially reduced after 4 months of treatment; nifedipine was discontinued. In the remaining 16 subjects, mean intraocular pressure, retrobulbar hemodynamics, visual field mean sensitivity, and contrast sensitivity at 3, 12, and 18 cycles per degree (cpd), respectively, were unchanged after nifedipine treatment. Contrast sensitivity at 6 cpd, however, improved after drug treatment (P = .004). Individuals with the greatest improvements in contrast sensitivity at 6 cpd showed the largest increases in ophthalmic arterial peak systolic velocity (r = .57; P = .02) and end-diastolic velocity (r = .65; P = .001). CONCLUSION: Nifedipine fails to provide uniform visual function or retrobulbar hemodynamic responses in patients with normal-tension glaucoma. Those patients who do show improved visual function also show improved indices of retrobulbar perfusion.

Optic nerve dysfunction during gravity inversion. Visual field abnormalities.

Inversion in a head-down position (gravity inversion) results in an intraocular pressure of 35 to 40 mm Hg in normal subjects. We used computerized static perimetry to measure the visual fields of normal subjects during gravity inversion. There were no visual field changes in the central 6 degrees of the visual field compared with the baseline (preinversion) values. However, when the central 30 degrees of the visual field was tested, reversible visual field defects were found in 11 of 19 eyes. We believe that the substantial elevation of intraocular pressure during gravity inversion may pose potential risks to the eyes, and we recommend that inversion for extended periods of time be avoided.

Ocular manifestations of gravity inversion.

To determine the ocular manifestations of inverting the human body into a head-down vertical position, we evaluated normal volunteers with applanation tonometry, fundus photography, fluorescein angiography, and ophthalmodynamometry. Compared with data obtained in the sitting position, the intraocular pressure more than doubled on inversion (35.6 +/- 4 v 14.1 +/- 2.8 mm Hg, n = 16), increasing to levels well within the glaucomatous range. Pressures in the central retinal artery underwent similar increases, while the caliber of the retinal arterioles decreased substantially. External ocular findings associated with gravity inversion included orbital congestion, conjunctival hyperemia, petechiae of the eyelids, excessive tearing (epiphora), and subconjunctival hemorrhage. We suggest that patients with retinal vascular abnormalities, macular degeneration, ocular hypertension, glaucoma, and similar disorders refrain from inversion altogether. Whether normal individuals will suffer irreversible damage from inversion is uncertain, but it seems prudent to recommend that prolonged periods of inverted posturing be avoided.