Erdem Ergun

Influence of hematocrit and platelet count on impedance and reactivity of whole blood for electrical aggregometry

Previous studies have shown that differing qualities of blood specimen seem to influence whole blood electrical aggregometry (WBEA), making it difficult to standardize the method. The aim of this study was to investigate the impact of hematocrit (HCT) and platelet count (PLC) on in vitro platelet aggregation in citrated whole blood (CWB) in order to compensate for their possible effects on impedance aggregometry. Red blood cells and blood platelets were isolated from fresh citrated whole blood taken from 15 healthy donors (mean age = 26 years) and recombined to 20 physiologically relevant combinations of hematocrit and platelet count (HCT: 20-50, PLC: 100-500). Platelet aggregability was measured using WBEA with three different triggers. A special-purpose software package was used in this study, ensuring proper calibration, acquisition, and evaluation of analogue to digital converted data, allowing the calculation of a set of characteristic parameters of each impedance curve. Most of the linear regressions showed that all parameters significantly depend on HCT and PLC. Furthermore, we found interactions of both variables, making it impossible to focus on the effects of one of the investigated variables only. The outcome of this study is a set of dependences, allowing the calculation of regressions for in vitro aggregation in whole blood, enabling a comparison of blood of any quality with each other, regardless of the variables HCT and PLC. Together with the previously defined dependence of sample age on WBEA data, this step should help to make this technique a more reliable and practicable clinical tool, making it suitable for daily routine investigations.

Ultrahigh resolution optical coherence tomography of macular holes.

Purpose: To evaluate ultrahigh resolution optical coherence tomography (UHR OCT) for visualization of intraretinal layers, especially the photoreceptor inner segment and outer segment layers, in eyes with macular holes and after surgical intervention. Methods: An UHR OCT system based on a titanium:sapphire laser was used, enabling in vivo cross-sectional retinal imaging with 3-&mgr;m axial resolution. Typical, representative tomograms of 5 of 48 eyes from 36 patients demonstrated the potential of UHR OCT to detect morphologic changes in different stages of full-thickness macular holes and changes induced by surgical intervention. Results: UHR OCT could detect subtle intraretinal changes in macular hole formation. Unprecedented visualization of photoreceptor impairment was achieved that appeared to be more extensive than the hole itself. Postoperatively, clinically closed holes showed restoration of the photoreceptor inner and outer segment layers of various extents, with residual disease in some eyes. Conclusion: In macular holes, UHR OCT allows for detection of even small morphologic changes of the retinal layers, especially the photoreceptor inner and outer segment layers. Therefore, it also represents a superior method to monitor the effect of surgical interventions. Preoperative photoreceptor impairment and the degree of postoperative restoration could possibly be associated with visual function. Hence, UHR OCT could lead to better understanding of macular hole pathogenesis and to more accurate disease prognosis.

Photodynamic therapy and vitelliform lesions.

Purpose: To investigate the effect of photodynamic therapy (PDT) with verteporfin on patients with vitelliform lesions caused by cuticular drusen or adult-onset foveomacular vitelliform dystrophy (AOFVD). Design: Observational case series. Patients and Methods: Eight eyes of seven patients from two centers were examined prospectively. Each patient received PDT with verteporfin applied to the vitelliform lesions. Results: Photodynamic therapy did not significantly affect the median visual acuity outcome (20/50 before PDT and 20/66 after PDT) in all seven treated patients. Of note, however, were four eyes of four patients who experienced a severe decrease in visual acuity after PDT with verteporfin. The temporary relationship of the vision loss to the treatment suggests that this may represent an adverse effect from therapy. The fluorescein angiographic appearance was virtually unchanged in all treated patients, whereas indocyanine green angiography showed typical PDT-associated reduction of choroidal perfusion in the treatment area. Conclusion: Photodynamic therapy does not have a positive influence on the visual outcome in patients with vitelliform lesions and may have a negative impact on vision in some treated patients. It is important for physicians using PDT to exercise caution in distinguishing between choroidal neovascular membranes and vitelliform lesions because the outcome in this latter group may be worse with application of PDT than with the natural course.

Rapid Communication The Mydriatic Effect of Tropicamide and its Diagnostic Use in Alzheimer's Disease

The mydriatic effect of topically administered tropicamide was investigated as a possible diagnostic indicator for Alzheimers disease. Although an initial series seemed to show a correlation between hypersensitivity to tropicamide and intellectual impairment, subsequent testing showed a greater inter- and intra-individual variation than that between the normal group and the group of patients with intellectual impairment. This procedure seems, therefore, to lack sufficient specificity to be useful for such a diagnostic purpose.

Prevalence of patients presenting with neovascular age-related macular degeneration in an urban population.

Purpose: To determine the number and type of new cases of neovascular age-related macular degeneration (AMD) present in a defined urban population and to establish the proportion that would be recommended for treatment with verteporfin or laser photocoagulation. Methods: Patients referred to an ophthalmic center in Vienna during a 10-week period because of recent deterioration in vision caused by newly diagnosed neovascular AMD were included. Results: Neovascular AMD was diagnosed in 168 eyes in 153 patients. One hundred one eyes (60.1%) had lesions that were occult with no classic choroidal neovascularization (CNV); of these, 70 were subfoveal, 19 were juxtafoveal, and 12 were extrafoveal. Thirty-five eyes (20.8%) had predominantly classic lesions; of these, 27 were subfoveal, 6 were juxtafoveal, and 2 were extrafoveal. Thirty-two eyes (19.0%) had minimally classic lesions, of which 31 were subfoveal and 1 was extrafoveal. In accordance with consensus guidelines from a panel of experts and with American Academy of Ophthalmology’s Preferred Practice Pattern guidelines, 33 lesions (17%) would be considered for treatment with verteporfin therapy. A further 37 subfoveal lesions with occult with no classic CNV and 7 juxtafoveal lesions with occult with no classic CNV might also benefit from verteporfin therapy if there is evidence of presumed recent disease progression. Five lesions (3.0%) could have been treated with laser photocoagulation according to Macular Photocoagulation Study criteria. Conclusions: These results suggest that verteporfin therapy substantially increases the number of patients with treatable neovascular AMD.

Incidence of laser photocoagulation and photodynamic therapy with verteporfin at a tertiary retinal center.

Purpose To examine the influence of photodynamic therapy (PDT) with verteporfin on the indication and frequency of conventional thermal krypton laser photocoagulation in choroidal neovascularization. Methods A retrospective chart review was performed comparing laser indication and frequency 1 year before and 2 years after PDT started to be used routinely following the guidelines of the Treatment of Age-Related Macular Degeneration with Photodynamic Therapy Study Group and the Verteporfin in Photodynamic Therapy Study Group. Results Similar frequencies of laser treatment were seen in the year before and during the first year after PDT was commenced (301 [7.1% of all patients] to 281 [6.9%]). In the year thereafter, however, there was a marked decrease in laser treatments (174 [3.9%]). Interestingly, there was a steady increase in the relative frequency of laser treatments of extrafoveal and parapapillary lesions in the years after PDT was commenced (29.2%, year 1; 30.6%, year 2; and 39.6%, year 3). Conclusion PDT has led to a decrease in conventional laser photocoagulation at one large tertiary retinal center in Austria. Moreover, it is our belief that patients are now referred at earlier stages of the disease, which has resulted in a shift in thermal laser indications.

Treatment frequency and visual outcome in subfoveal choroidal neovascularization related to pathologic myopia treated with photodynamic therapy.

BackgroundThe purpose of this study was to examine the influence of treatment frequency on visual acuity of patients with PDT treatment for subfoveal predominantly classic CNV related to pathological myopia.DesignRetrospective case series.MethodsThirty-seven patients with subfoveal predominantly classic CNV caused by pathologic myopia and treated with PDT were included. All patients received a full ophthalmic examination, including best-corrected visual acuity, slit-lamp biomicroscopy, fundus photography and fluorescein angiography, before first treatment and every 3 months thereafter. Photodynamic therapy was performed according to standard protocol. Main outcome measurements were visual acuity and treatment frequency.ResultsThe number of treatments received was 3.35±1.83 (average: 1–7). In 12 eyes (32.43%); the BCVA was stable or increased during the entire follow-up period. In eight eyes (21.62%), the BCVA decreased and did not return to the baseline values. A transient loss of visual acuity (over 3–9 months) with subsequent improvement in visual function was found in 68% (17 eyes). A gain of three or more lines compared with lowest BCVA was found in 56% (14 eyes). The number of treatments did not correlate with baseline BCVA, greatest linear dimension of CNV at baseline or with the change of BCVA from baseline. In cases with transient worsening of BCVA, the recovery of visual acuity correlated significantly with the number of treatments (r=−0.522, P<0.05; Spearman rank correlation) received.ConclusionVisual acuity recovery correlates with the number of PDT re-treatments; in many cases, an improvement in visual function after temporary decrease of BCVA can be observed after re-treatment according to current treatment guidelines. The number of PDT treatments has no negative effect on the visual outcome in subfoveal CNVs caused by pathological myopia.

Altitudinal neglect in a patient with occipital infarction

Visual neglect has been frequently described in a horizontal direction. Altitudinal neglect, however, has rarely been described and has been associated with bilateral lesions in the parieto-occipital or temporo-occipital region. The following case report presents a patient with marked altitudinal neglect of the inferior space which was elicited using a line bisection test. The previously healthy patient had well-defined lesions solely in the occipital cortex following an embolic infarction. The present case report underlines the possibility that bioccipital lesions themselves can be responsible for altitudinal neglect.

The efficient use of perimetry for neuro-ophthalmic diagnosis.

AIMS/BACKGROUND: Automated perimetry is both one of the most important diagnostic procedures in ophthalmology and the most difficult for the patient who is required to comply with strict and tiring conditions. This paper examines the use of a moving fixation target and a strategy for full threshold determination only in those data points found to be abnormal. METHODS: 142 eyes in 71 patients were subjected to two types of visual field tests: the Dicon TKS 4000 Autoperimeter program 5 and the Humphrey field analyser program 30/2. The first procedure was compared with a commonly used instrument and strategy that is usually employed for the management of glaucoma patients. RESULTS: Such a strategy was used in patients presenting with neuro-ophthalmic problems taking an average testing time of 14.9 minutes. The alternative test described here took an average of 3.9 minutes, without loss of diagnostic value. CONCLUSION: The shorter testing time results in greater patient acceptance, fewer fatigue induced artefacts, and the possibility of completing a perimetry test with patients whose ability might seriously be challenged by a longer test. The reduced time required and the more natural condition of not having to fixate on an unmoving position were found not to reduce the diagnostic value of the data produced in patients presenting for various reasons at a neuro-ophthalmology clinic.

Incidence of patients presenting with exudative maculopathy and neovascular retinal disease in an urban population

SummaryPURPOSE: To determine the incidence of exudative macular and neovascular retinal disease presenting within a defined urban population. STUDY DESIGN: Prospective, observational, consecutive case series. PATIENTS AND METHODS: Patients referred to ten ophthalmic centers within a defined 10-week period with a newly diagnosed exudative macular and/or neovascular retinal disease were examined fundoscopically and angiographically and quantified according to age and underlying disease. RESULTS: A total of 527 eyes of 426 patients were referred. The most frequent disease was neovascular age-related macular degeneration (AMD) (199 of 527, 37.8%, 184 patients), followed by diabetic maculopathy and/or proliferative diabetic retinopathy (199 of 527, 37.8%, 128 patients) and venous occlusive disease (67 of 527, 12.7%, 67 patients). The majority of neovascular AMD consisted of occult without classic choroidal neovascularization (CNV) (115 of 199, 57.8%); predominantly classic CNV was seen more often than minimally classic CNV (43 of 199, 21.6%, vs. 27 of 199, 13.6%). The overwhelming majority of the diabetic cases had diabetic macular edema (179 of 199, 89.9%); only 10.1% had vasoproliferative disease. All other causes of CNV, macular edema and exudation, and retinal neovascularization were observed in <5% of all patients. CONCLUSION: The main causes of exudative maculopathy are CNV due to neovascular AMD and diabetic macular edema. Proliferative diabetic retinopathy is the main cause of retinal neovascularization. The number of patients with neovascular AMD presents a future challenge for ophthalmologists.