Blood Pressure Effects on Retinal Vessel Diameter and Flicker Response: A 1.5-Year Follow-Up

PURPOSE

The study examined the influence of individual blood pressure changes overtime on retinal vessel diameter and the latter's response to flicker light.

METHODS

The diameter of a retinal arterial and venous segment was measured continuously on-line with a Dynamic Vessel Analyzer in 20 patients twice (mean interval between examinations of 24 months). Eleven patients had no cardiovascular disease. Nine patients had arterial hypertension and were untreated at the time of the first measurement; at the time of the second measurement they were undergoing various antihypertensive therapies. Each test consisted of a 50-s baseline plus three 20-s periods of flicker stimulation followed by an 80-s period of observation. During the examinations the blood pressure was measured at 1-minute intervals.

RESULTS

In the hypertension group changes in the mean arterial blood pressure (MAP) correlated significantly with changes in the arterial baseline diameter (y = -0.1 - 0.37x, r =0.74, p (increase) <0.03). A comparison of the two measurements showed no such relationship in the group of cardiovascularly healthy subjects. The venous baseline and the arterial and venous flicker response did not change significantly in either group between the two measurements and showed no relationship to blood pressure changes.

CONCLUSIONS

In hypertensive subjects, long-term therapy-related changes in blood pressure induced a change in the arterial baseline by approximately +3.7 microm/-10 mmHg MAP. An influence of lowering MAP to the arterial flicker response could not be detected.

[Can Anti-VEGF Injections Cause Glaucoma or Ocular Hypertension?]

An increasing number of patients receive intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections with a high frequency for the treatment of neovascular macular disease. Since the volume of the vitreous body is temporarily increased by the injection of the substances, a short-term intraocular pressure increase after the introduction of the substance is not uncommon. However, there are more and more reports indicating that multiple injections may lead to a long-term increase in intraocular pressure. This may also be the case in patients without a glaucoma history. In some cases, this pressure increase cannot be adequately treated with local pressure-reducing medication and requires an operative procedure in order to avoid glaucoma damage. This appears to be more common in products dispensed from broken bulk or after administration of bevacizumab. The mechanism leading to inflammation and/or a sustained increase in pressure is unknown. High molecular weight molecules present in the syringe, such as monomer antibodies, aggregated proteins, or silicone oil droplets from the syringe, may lead to inflammation in the trabecular meshwork or displacement thereof and a subsequent increase of the intraocular pressure. Avoiding silicone oil droplets in the syringes would be desirable. Intraocular pressure after intravitreal injections should also be monitored long term after the procedure.

[Ophthalmological alterations at the initial diagnosis of HIV infection]

Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV), is one of the most important infectious causes of death in the twentieth and twenty-first centuries. Ocular manifestations can appear in particular when the CD4 cell count is low. This article presents a case report of a 38-year-old homosexual man in whom HIV microangiopathy retinopathy syndrome (MAPS) was found during the assessment of the initial HIV diagnosis. Typical findings in MAPS are conjunctival and retinal vessel abnormalities, cotton wool spots as well as intraretinal hemorrhages. Loss of vision is a rare complication but MAPS shows an impairment of the immune status and is also associated with a higher mortality.

[Preservative-containing eye drops and adherence in ophthalmological practice]

Chronic eye diseases, such as glaucoma or dry eye syndrome, require long-term drug application to the eyes. Good adherence is required to achieve the therapeutic goal and patient needs and requirements have to be taken into account. This distinguishes adherence to drug therapy from the former compliance which implies only following medical instructions. Adherence is influenced by socioeconomic, health system-related, disease-related, treatment-related and patient-related factors. It can be measured by tedious procedures, such as electronic monitoring, self-assessment, drop counting and laboratory findings of systemic drug levels. Non-adherence is a growing medical problem worldwide. An increase in adherence means an increased degree of therapeutic safety for the patient and long-term cost savings for the individual as well as society. Non-adherence in chronic diseases, such as glaucoma and dry eye syndrome is increased by eye drops that cause side effects. Often these side effects are caused by agents such as the preservative benzalkonium chloride. To achieve a good adherence preservative-free eye drops are advised.

[Measurement of accommodation using optical biometry]

BACKGROUND

Making accommodation possible for all age groups is a topic of great interest. We applied optical biometry in order to study the physiological mechanisms in detail. Longitudinal relations in the optical axis were measured during accommodation in volunteers of different ages and lens states.

METHODS

A total of 60 subjects (children, adolescents, adults, and pseudophakes) were examined using the IOL Master. We measured anterior chamber depth (ACD), axial length (AL), and changes in these two measurements during accommodation.

RESULTS

Near accommodation (NA) in adolescents caused the largest ACD decrease (0.14+/-0.03 mm). ACD decreased in adults during NA but not in pseudophakic patients of comparable age. AL increased during NA in all groups by 0.01+/-0.01 mm.

CONCLUSIONS

ACD decreased with age. Using a physiological stimulus, no change in ACD was measured during NA in pseudophakic patients. The documented increase in AL needs to be evaluated further.

[Treatment of wrinkles with botulinum toxin]

The use of botulinum toxin A for the treatment of wrinkles is increasing. Botulinum toxin A inhibits exocytosis of acetylcholine from 3 to 12 months, depending on the target tissue. Low-dose botulinum toxin A is used to smooth hyperkinetic facial lines. This is especially successful in the upper facial parts, since the target muscles (procerus, corrugator supracilii, frontalis, orbicularis oculi) all directly overlie the osseous structures of the face. This is not the case for the lower facial parts, and more side effects are encountered when treating, for example, wrinkles around the mouth. Contraindications to the use of botulinum toxin A are diseases affecting neuromuscular signal transduction, allergic reactions to components of the solution, therapy with aminoglycosides or acetylsalicylic acid prior to treatment, infections in the planned treatment area, and pregnancy and lactation. Alternative and complementary treatments include erbium-YAG or CO2 laser, as well as augmentation and surgical plastic procedures.

[Low-dose rate brachytherapy with locally integrated beta emitters after internal urethrotomy. A pilot project using an animal model]

BACKGROUND

The treatment of urethral strictures represents an unsolved urological problem.

PATIENTS AND METHODS

The effect of a (32)P-coated urethral catheter in the sense of low-dose rate brachytherapy to modulate wound healing will be analyzed in an animal experiment.

RESULTS

Unfortunately it is not possible to present any results because this is being studied for the first time and there are no experiences with low-dose rate brachytherapy and this form of application in the lower urinary tract. Furthermore the animal experiment will only start in the near future. Both decade-long experiences with radiotherapy to treat benign diseases and our own results of previous studies in otolaryngology and ophthalmology let us expect a significantly lower formation of urethral strictures after internal urethrotomy.

CONCLUSION

This study will contribute to improving the treatment of urethral strictures as demanded in previous papers.

Vergleich der Durchmesserreaktion retinaler Arterien und Venen auf Flickerlicht

PURPOSE

The aim of this study was to compare the diameter response of retinal arteries and veins after provocation with flickering light regarding the amplitude and temporal course.

METHODS

The study included 26 healthy volunteers. The vessel diameter was automatically and continuously measured by the retinal vessel analyzer. The examination consisted of a baseline measurement (100 s) followed by five periods of 20-s flicker light provocation and 80-s follow-up observation.

RESULTS

A diameter dilation was observed immediately after the end of the flicker period in arteries (6.9+/-2.8%) and veins (6.5+/-2.8%, difference n.s.). The quotient of arterial and venous dilation (AVDQ) was 1.25+/-0.69 (range: 0.2-2.8). A significant correlation of age and arterial or venous dilation or the AVDQ was not observed. The arterial diameter reduced faster than the venous and reached a minimum of -2.7+/-1.4% at 25.9+/-10.8 s after the end of the flicker phase. The veins were dilated by 0.5+/-1.3% at the time of the maximal individual arterial constriction (p<0.0001).

CONCLUSIONS

Flicker-evoked response of retinal arteries and veins did not differ in the dilative amplitude but in the temporal course of the abatement of the dilation.

Retinal Vessel Analysis--new possibilities

Retinal Vessel Analysis is a new technique to assess behavior of large retinal vessels based on diameter measurements. The Retinal Vessel Analyzer (RVA) measures continuously on-line obtaining data in relation to time and local position. Possible analysis tools include (a) Time Course Analysis of physiological, pathological, or therapy induced changes; (b) Local Course Analysis to recognize local narrow or wide vessel segments along the vessel; (c) Vasomotoric Analysis to determine vasomotions and blood pressure related diameter changes; (d) Functional Analysis to examine dynamic behavior e.g. the ability to autoregulate and (e) Functional Imaging to visualize functional parameters of vessels in single vessel segments. RVA is thus able to recognize and study different autoregulation mechanisms.

Functional analysis of retinal vessel diameter reaction to artificially raised intraocular pressure in glaucoma patients with and without dorzolamide therapy

BACKGROUND

Examination of the influence of dorzolamide on the autoregulation of retinal vessel diameter in glaucoma patients.

PATIENTS AND METHODS

Eleven patients with primary open angle glaucoma (age 60 +/- 11) without medication and four weeks after starting therapy with dorzolamid eye drops three times daily were examined in the study. Short-time rise of intraocular pressure (IOP) was obtained via suction-cup. Functional reaction of the diameter of a segment of a retinal artery and corresponding vein were assessed by retinal vessel analyzer.

RESULTS

Dorzolamid lowered the IOP from 23.3 +/- 1.3 to 17.6 +/- 2.2 mmHg (p = 0.004). Therapy did not influence the absolute diameter of retinal vessels regarding maximal dilatation caused by the pressure rising provocation. In eyes with treatment the diameter decreased faster to baseline values (arteries 100 sec, veins 220 sec) compared to those without treatment (arteries 350 sec, veins 480 sec).

CONCLUSION

Dorzolamid might possibly be able to accelerate autoregulation of retinal vessels in response to short term artificial IOP increase.

[The radiological diagnosis of an intraorbital bullet projectile]

Beside conventional X-ray examination, ultrasound and computer tomographic examination are accepted radiologic techniques to assess the extend of damage of intraorbital injuries. With the exception of a few reports in the literature there is agreement that intraorbital metallic foreign bodies and gun-shot bullets represent a contraindication for magnetic resonance (MR) imaging examination because of artificial imaging side effects and the potential of secondary dislocation of the metallic foreign body due to ferromagnetism. By means of the case reported here it is shown that this general opinion is not universally valid. Depending on the elemental metallic composition of foreign bodies and gun-shot bullets it is demonstrated that MR examination allows high-resolution illustration and in some cases is advantageous compared with other radiologic imaging techniques.

Imaging of eye movement with fast MRI

PURPOSE

Imaging of eye movement disorders has so far been restricted to the semifunctional cine mode of CT and MRI. Since real-time imaging of eye movement is necessary to investigate dynamic disorders, the aim of our study was to implement a fast MR technique to investigate eye movement in a real-time mode.

METHOD

Six healthy volunteers and three patients suffering from end-point nystagmus were examined with fast MR sequences while performing the following eye movements: holding different gaze positions, reading a defined text to demonstrate saccadic movements, and holding a primary gaze position and maximal end-point position to cause nystagmus when present.

RESULTS

In all cases, we were able to delineate eye movement with fast MRI. Anatomic and functional information could be obtained simultaneously for the first time through observation of saccadic and pursuit eye movements.

CONCLUSION

Fast MRI allows for the assessment of dynamic eye movement without the restrictions of cine mode and is able to provide the clinician with additional information in the evaluation of functional movement disorders.