Malignant Keratitis Caused by a Highly-Resistant Strain of Fusarium Tonkinense from the Fusarium Solani Complex.

Fusarium spp. are moulds ubiquitously distributed in nature and only occasionally pathogenic for humans. Species of the Fusarium solani complex are the predominant keratitis-inducing pathogens, because they are endowed with proper virulence factors. These fungi can adhere to the cornea creating a biofilm and, with the help of enzymes and cytotoxins, penetrate the cornea. Whereas an intact cornea is hardly able to be invaded by Fusarium spp. in spite of appropriate virulence factors, these opportunistic fungi may profit from predisposing conditions, for example mechanical injuries. This can lead to a progressive course of corneal infection and may finally affect the whole eye up to the need for enucleation. Here, we present and discuss the clinical, microbiological and histopathological aspects of a particular case due to Fusarium tonkinense of the Fusarium solani complex with severe consequences in a patient without any obvious predisposing factors. A broad portfolio of antifungal agents was applied, both topically and systemically as well as two penetrating keratoplasties were performed. The exact determination of the etiologic agent of the fungal infection proved likewise to be very challenging.

New Antimycotics in the Pipeline - For Ophthalmology Too? / Neue Antimykotika in der Pipeline ­ auch für die Augenheilkunde?

Seven new antimycotics are presented that are at different points of development or approval. These substances are mainly first-in-class drugs. They are primarily developed for systemic administration. However, with the support of a pharmacist, the intravenous formulation may be used as eyedrops. In this short review, the activities of the substances against various fungal infections are described. After unsuccessful conventional therapy of fungal eye infections, one of these new substances might be suitable to cure the mycosis.

Keratomycosis due to Tintelnotia destructans refractory to common therapy treated successfully with systemic and local terbinafine in combination with polyhexamethylene biguanide.

PURPOSE: To report on a wearer of rigid gas-permeable contact lenses with a keratomycosis due to Tintelnotia-a new genus of Phaeosphaeriaceae-treated with terbinafine and polyhexamethylene biguanide. METHODS: Chart review of a patient with fungal keratitis treated additionally with systemic and topical terbinafine 0.25% after symptoms increased under conventional antimycotic therapy with voriconazole. Antifungal susceptibility had been tested in vitro. RESULTS: After starting an additional treatment with systemic and topical terbinafine, the severe corneal infection was sufficiently resolved. The drug was well tolerated without any neurological, dermatological or gastroenterological problems. Terbinafine revealed a marked in vitro antifungal activity of 0.12 µg/ml. The fungus was identified as Tintelnotia destructans. CONCLUSIONS: Terbinafine might be considered as a therapeutic option in severe cases of fungal keratitis refractory to common antifungal therapy.

VEP-based acuity assessment in low vision.

PURPOSE: Objective assessment of visual acuity (VA) is possible with VEP methodology, but established with sufficient precision only for vision better than about 1.0 logMAR. We here explore whether this can be extended down to 2.0 logMAR, highly desirable for low-vision evaluations. METHODS: Based on the stepwise sweep algorithm (Bach et al. in Br J Ophthalmol 92:396-403, 2008) VEPs to monocular steady-state brief onset pattern stimulation (7.5-Hz checkerboards, 40% contrast, 40 ms on, 93 ms off) were recorded for eight different check sizes, from 0.5° to 9.0°, for two runs with three occipital electrodes in a Laplace-approximating montage. We examined 22 visually normal participants where acuity was reduced to ≈ 2.0 logMAR with frosted transparencies. With the established heuristic algorithm the "VEP acuity" was extracted and compared to psychophysical VA, both obtained at 57 cm distance. RESULTS: In 20 of the 22 participants with artificially reduced acuity the automatic analysis indicated a valid result (1.80 logMAR on average) in at least one of the two runs. 95% test-retest limits of agreement on average were ± 0.09 logMAR for psychophysical, and ± 0.21 logMAR for VEP-derived acuity. For 15 participants we obtained results in both runs and averaged them. In 12 of these 15 the low-acuity results stayed within the 95% confidence interval (± 0.3 logMAR) as established by Bach et al. (2008). CONCLUSIONS: The fully automated analysis yielded good agreement of psychophysical and electrophysiological VAs in 12 of 15 cases (80%) in the low-vision range down to 2.0 logMAR. This encourages us to further pursue this methodology and assess its value in patients.

Feasibility study: 7 T MRI in giant cell arteritis.

OBJECTIVES: To assess the detectability of vasculitic changes of the superficial cranial arteries with contrast-enhanced 7 T MRI in three patients with GCA and intraindividual comparison with 3 T MRI. METHODS: Three patients (two female, one male) with suspected GCA underwent contrast-enhanced T1-weighted high-resolution MRI at 3 T and 7 T magnetic field strength. The clinical diagnosis, based on criteria of the American College of Rheumatology, was confirmed by biopsy of the superficial temporal artery after MRI. MR images were visually assessed for detection of vasculitic mural contrast enhancement and vessel wall thickening of the superficial cranial arteries. RESULTS: Both 3 T and 7 T MRI allows for visualisation of mural inflammatory changes and assessment of the vasculitic involvement pattern. Image quality of 7 T MRI was rated superior to image quality of 3 T MRI scans. CONCLUSIONS: 7 T MR imaging of vasculitic changes in patients with GCA is possible, and suggests superior image quality. Larger patient studies are necessary to quantify the diagnostic advantages of 7 T MRI.

Impact of chiasma opticum malformations on the organization of the human ventral visual cortex.

Congenital malformations of the optic chiasm, such as enhanced and reduced crossing of the optic nerve fibers, are evident in albinism and achiasma, respectively. In early visual cortex the resulting additional visual input from the ipsilateral visual hemifield is superimposed onto the normal retinotopic representation of the contralateral visual field, which is likely due to conservative geniculo-striate projections. Counterintuitively, this organization in early visual cortex does not have profound consequences on visual function. Here we ask, whether higher stages of visual processing provide a correction to the abnormal representation allowing for largely normal perception. To this end we assessed the organization patterns of early and ventral visual cortex in five albinotic, one achiasmic, and five control participants. In albinism and achiasma the mirror-symmetrical superposition of the ipsilateral and contalateral visual fields was evident not only in early visual cortex, but also in the higher areas of the ventral processing stream. Specifically, in the visual areas VO1/2 and PHC1/2 no differences in the extent, the degree of superposition, and the magnitude of the responses were evident in comparison to the early visual areas. Consequently, the highly atypical organization of the primary visual cortex was propagated downstream to highly specialized processing stages in an undiminished and unchanged manner. This indicates largely unaltered cortico-cortical connections in both types of misrouting, i.e., enhanced and reduced crossing of the optic nerves. It is concluded that main aspects of visual function are preserved despite sizable representation abnormalities in the ventral visual processing stream.

Differential effects of head-mounted displays on visual performance.

Head-mounted displays (HMDs) virtually augment the visual world to aid visual task completion. Three types of HMDs were compared [look around (LA); optical see-through with organic light emitting diodes and virtual retinal display] to determine whether LA, leaving the observer functionally monocular, is inferior. Response times and error rates were determined for a combined visual search and Go-NoGo task. The costs of switching between displays were assessed separately. Finally, HMD effects on basic visual functions were quantified. Effects of HMDs on visual search and Go-NoGo task were small, but for LA display-switching costs for the Go-NoGo-task the effects were pronounced. Basic visual functions were most affected for LA (reduced visual acuity and visual field sensitivity, inaccurate vergence movements and absent stereo-vision). LA involved comparatively high switching costs for the Go-NoGo task, which might indicate reduced processing of external control cues. Reduced basic visual functions are a likely cause of this effect.

Systemic iodine absorption associated with the use of preoperative ophthalmic antiseptics containing iodine.

BACKGROUND: Polyvinylpyrrolidone-Iodine (PVP-I) is routinely used as preoperative antiseptic during ophthalmic surgery. Iodine absorption from iodine-containing antiseptics can lead to the development of thyroid disorders. Therefore, a quantitative measurement of iodine absorption from these antiseptics was performed in patients undergoing elective cataract surgery. METHODS: This study enrolled 241 patients to evaluate systemic iodine absorption after exposure to conjunctival and/or periorbital 1.25% and 10% PVP-I compared to an iodine-free antiseptic. RESULTS: All patients who received the 10% PVP-I regardless of the application site showed a 1.2-1.5-fold increase in urinary iodine excretion after 24 h (p = 0.01). In 17 out of 110 (15.5%) patients in whom 10% PVP-I was used, the critical threshold of urinary iodine excretion as defined by WHO (>300 µg/L) was exceeded. In contrast, no significant ioduria was observed with the use of 1.25% PVP-I except in patients after 48 h (p = 0.01) and with a concurrent conjunctival and periorbital application. The proportion of the excreted iodine in urine ranged from 0.24% to 1.77%. No correlation was found between the total applied concentration of iodine and the amount excreted in urine. CONCLUSION: Based on our findings, we believe that the use of 10% PVP-I as preoperative ophthalmic antiseptic should undergo further clinical evaluation in regard to its impact on thyroid function. Conjunctival or periorbital application of 1.25% PVP-I does not result in significant ioduria.

Comparison of Goldmann applanation and dynamic contour tonometry before and after cataract surgery.

PURPOSE: To validate changes in intraocular pressure (IOP) after phacoemulsification with intraocular lens (IOL) implantation without pressure-lowering surgery in previously unoperated eyes of normal and glaucoma patients. SETTING: University Eye Clinic, Otto-von-Guericke-University, Magdeburg, Germany. DESIGN: Cohort study. METHODS: The IOP in both eyes of patients was determined by Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) 1 to 2 days before and after uneventful unilateral surgery. Central corneal thickness was used to correct raw GAT readings. RESULTS: Of the 50 patients having unilateral phacoemulsification, 29 had had cataract extraction in the contralateral eye. The mean baseline IOP was 17.4 ± 4.4 mm Hg (GAT) and 16.6 ± 2.9 mm Hg (DCT). Postoperatively, the GAT IOP decreased to 16.4 ± 6.5 mm Hg and the DCT IOP increased slightly to 17.1 ± 4.1 mm Hg. The mean tonometer difference (ΔIOP = GAT - DCT) amounted to ΔIOP(pre) = +0.75 ± 2.69 mm Hg in phakic eyes and ΔIOP(post) = -0.70 ± 3.76 mm Hg in pseudophakic eyes (P=.0011). Consistent results were found in pairs of phakic eyes and pseudophakic eyes (mean IOP 18.0 ± 4.8 mm Hg [GAT] and 17.0 ± 3.3 mm Hg [DCT]). In fellow eyes, the mean GAT reading was 13.4 ± 4.4 mm Hg and the mean DCT value, 14.8 ± 2.4 mm Hg. ΔIOP(phakic) was +1.04 ± 2.75 mm Hg and ΔIOP(pseudophakic) was -1.48 ± 2.78 mm Hg (P=.00000021). CONCLUSIONS: The GAT IOP readings in pseudophakic eyes seemed to be falsely low. Hence, special attention in the screening, diagnosis, and management of glaucoma is necessary.

Effect of blue-light filtering on multifocal visual-evoked potentials.

PURPOSE: To perform an objective functional assessment of the impact of blue-light filters on cortical processing to evaluate the potential side effects of the filters on higher tier visual function at the neural level. SETTING: Department of Ophthalmology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany. DESIGN: Cohort study. METHODS: Multifocal pattern-reversal visual-evoked potentials (multifocal VEPs) were recorded monocularly in pseudophakic patients with a clear intraocular lens (IOL) under 2 conditions: (1) stimulus perception through a yellow filter with the filter characteristics of an AF-1 YA-60BB IOL (blue filtering); (2) stimulus perception through a neutral filter that homogeneously attenuates the effective stimulus intensity as under the blue-light filtering condition but independent of the wavelength (neutral filtering). Second-order kernel multifocal VEPs were extracted for 60 visual field locations, and amplitude and latency effects were determined for 6 stimulus eccentricities. RESULTS: The study evaluated 20 patients. Typical multifocal VEPs were obtained for the blue-light and neutral filtering conditions at all eccentricities. No significant effects on amplitudes were obtained, and a subtle latency effect (<0.5 millisecond delay for neutral filtering; P<.02) did not reach significance in an eccentricity-specific analysis. CONCLUSIONS: The induced short-term change in the spectral composition of the visual stimulus left neural activity at the level of the primary visual cortex largely unaffected, providing an objective account of the integrity of visual processing under this condition.

Noninvasive assessment of intracranial pressure with venous ophthalmodynamometry. Clinical article.

OBJECT: Venous ophthalmodynamometry is a technique used to register the pressure within the central retinal vein. Because the outflow of the central retinal vein is exposed to the intracranial pressure (ICP), the pressure of the central retinal vein may be correlated with the ICP. In the absence of adequate statistical evidence, the authors compared the pressure of the central retinal vein with results of simultaneous invasive monitoring of ICP in neurosurgical patients. METHODS: The pressure within the central retinal vein was recorded in 102 patients, in whom invasive continuous monitoring of ICP had become necessary for various reasons, mostly because of suspected hydrocephalus and intracranial hemorrhage. RESULTS: A highly significant correlation of the pressure in the central retinal vein and the intracranial cavity was confirmed statistically. An increased pressure of the central retinal vein indicated an elevated ICP, with a probability of 84.2%, whereas a normal pressure of the central retinal vein indicated a normal ICP in 92.8% of patients. Conclusions Venous ophthalmodynamometry is a valuable technique for the noninvasive assessment of ICP.

Optic nerve projections in patients with primary ciliary dyskinesia.

PURPOSE: Recently, it has been suggested that misprojections of the temporal retina to the contralateral hemisphere might not be specific for patients with albinism and might also be associated with the Kartagener syndrome (i.e., with situs inversus totalis in the presence of primary ciliary dyskinesia [PCD]). The authors tested whether such projection abnormalities are associated with PCD and situs inversus. METHODS: In 10 patients with PCD (five with situs inversus totalis) and in 10 age- and sex-matched controls, visual evoked potentials (VEPs) were recorded monocularly, as follows: conventional pattern-onset VEPs (cVEPs) and multifocal VEPs (mfVEPs) for 60 locations constituting a visual field of 44° diameter. cVEPs from 13 albinotic subjects were included as a reference. For each eye, interhemispheric difference potentials were calculated and correlated with each other to assess the lateralization of the responses: positive and negative correlation coefficients indicated lateralizations on same or opposite hemispheres, respectively. Misrouted optic nerves are expected to yield negative interocular correlations. RESULTS: For both cVEPs and mfVEPs, the distribution of the correlation coefficients in the PCD patients yielded largely positive values and did not differ from that of the controls. Consequently, neither large- nor small-scale lateralization abnormalities were observed in PCD. Further, the optic nerve projection did not depend on the presence of situs inversus. CONCLUSIONS: The absence of evidence for projection abnormalities in a cohort of 10 subjects with PCD, five of whom had Kartagener syndrome, underscores that misrouting of the optic nerves is not a common trait of these subjects.

Self-organisation in the human visual system--visuo-motor processing with congenitally abnormal V1 input.

Due to an abnormal projection of the temporal retina the albinotic primary visual cortex receives substantial input from the ipsilateral visual field. To test whether representation abnormalities are also evident in higher tier visual, and in motor and somatosensory cortices, brain activity was measured with fMRI in 14 subjects with albinism performing a visuo-motor task. During central fixation, a blue or red target embedded in a distractor array was presented for 250 ms in the left or right visual hemifield. After a delay, the subjects were prompted to indicate with left or right thumb button presses the target presence in the upper or lower hemifield. The fMRI responses were evaluated for different regions of interest concerned with visual, motor and somatosensory processing and compared to previously acquired data from 14 controls. The following results were obtained: (1) in albinism the hit rates in the visuo-motor task were indistinguishable from normal. (2) In area MT and the intraparietal sulcus there was an indication of abnormal lateralisation patterns. (3) Largely normal lateralisation patterns were evident in motor and somatosensory cortices. It is concluded that in human albinism, the abnormal visual field representation is made available for visuo-motor processing with a motor cortex that comprises an essentially normal lateralisation. Consequently, specific adaptations of the mechanisms mediating visuo-motor integration are required in albinism.

Minor effect of blue-light filtering on multifocal electroretinograms.

PURPOSE: To assess the impact of blue-light filtering on retinal processing to evaluate potential side effects of these filters on visual function at the neural level. SETTING: Department of Ophthalmology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany. DESIGN: Cohort study. METHODS: Multifocal electroretinograms (ERGs) were recorded monocularly after pupil dilation in pseudophakic patients with a colorless intraocular lens (IOL) under 2 conditions: (1) stimulus perception through a yellow-tinted filter with the filter characteristics of the AF-1 YA-60BB IOL (blue-light filter) and (2) stimulus perception through a neutral filter that homogeneously attenuates the effective stimulus intensity like the blue-light filter independent of the wavelength. First-order kernel multifocal ERGs were extracted at 61 visual field locations and averaged for 5 stimulus eccentricities. Amplitudes and implicit times were determined for the multifocal ERG components N1 (first negative deflection), N2 (second negative deflection), and P1 (first positive deflection). RESULTS: The study evaluated 20 patients. Typical multifocal ERGs were obtained for both conditions at all eccentricities. There were no significant differences in amplitudes or implicit times between the 2 conditions except for a slight P1 amplitude enhancement (6.9%) with the blue-light filter at an intermediate eccentricity (P = .003). CONCLUSIONS: The bipolar cell-dominated multifocal ERG was largely unaffected by short-term effects of blue-light filtering. The induced change in the spectral composition of the stimulus did not significantly alter the activity at the input stage of the visual system, specifically the retinal network comprising photoreceptors, horizontal cells, and bipolar cells.

Colorimetric analysis of three editions of the Velhagen-Broschmann pseudoisochromatic colour plates.

PURPOSE: Chromatic variations across different copies and different editions of pseudoisochromatic tests and violation of underlying principles of construction for individual plates can influence test results. METHODS: We analysed the colorimetric characteristics of three different editions of Velhagen-Broschmann pseudoisochromatic plates (30th edition printed in 1995, 31st edition printed in 1997, 32nd edition printed in 2000). One hundred and twelve coloured dots of 18 plates were chosen from each edition. We measured RGB and CIE XYZ values using a spectrophotometer. Differences in lightness and chromaticity between corresponding dots of different editions were analysed in terms of Delta L* and Delta u'v', respectively. For each plate deviations from dichromatic confusion lines were analysed. Furthermore, we determined the relative luminance of a target compared to its background in terms of the Weber contrast. RESULTS: The mean Delta L* across editions was 2.05 (+/-1.4) and the mean Delta u'v' was 0.0078 (+/-0.0029). For two plates the deviations of targets from dichromatic confusion lines exceeded suggested values. For a number of plates, the lightness contrast between the symbol and its background was high. Comparison with psychophysical data showed that these colour plates are easily detectable by colour-deficient observers. CONCLUSIONS: Lightness and chromatic variation across the three editions was moderate except for a small number of plates perhaps due to inaccuracies in the printing process. The design of several plates should be revised according to standard principles of construction of colour deficiency tests.

Toric intraocular lenses--theory, matrix calculations, and clinical practice.

PURPOSE: To describe 1) how to determine toric (posterior chamber) intraocular lenses (IOLs) with standard formulas, 2) a matrix-based calculation scheme for determining toric IOLs using 4x4 matrices, 3) a method to determine residual refraction after implantation of an arbitrary toric lens, and 4) to address clinical aspects. METHODS: Formulas and metrics are reviewed for determining IOL power and residual refraction after toric IOL implantation. RESULTS: From 4x4 refraction and translation matrices characterizing refractive surfaces and interspaces between refractive surfaces, a system matrix is determined characterizing the entire optical system paraxially. Toric posterior chamber IOLs are determined by solving a linear equation system. In a second step, the same methodology is used for estimation of the residual refraction at the spectacle plane after implantation of an arbitrary toric lens. The methodology is applied to working examples, and the calculation procedure is described in a step-by-step approach. CONCLUSIONS: A straight-forward en bloc concept is demonstrated for determination of toric IOLs and estimation of the residual refraction. The applicability is shown in working examples, and clinical aspects such as rotation of the lens implant are addressed.

Retinal vein occlusion and low-dose fibrinolytic therapy (R.O.L.F.): a prospective, randomized, controlled multicenter study of low-dose recombinant tissue plasminogen activator versus hemodilution in retinal vein occlusion.

PURPOSE: To investigate the efficacy of intravenous thrombolysis with low-dose recombinant tissue plasminogen activator (rt-PA) in recent-onset central retinal vein occlusion (CRVO) or branch retinal vein occlusion. METHODS: This was a prospective, randomized, controlled multicenter trial in patients with CRVO or branch retinal vein occlusion, best-corrected visual acuity < or =20/50, and onset of symptoms within 11 days before treatment. In each group, patients were randomized to either hemodilution or thrombolysis with 50 mg of rt-PA with concomitant intravenous heparinization. The primary clinical outcome measure was improvement in best-corrected visual acuity from baseline at 1 year. RESULTS: Fifty-two subjects were enrolled in the study. Patients with CRVO (n = 41) who were treated with rt-PA exhibited a significant improvement in best-corrected visual acuity compared with those who received hemodilution (P < 0.0001). At 1-year follow-up, the proportion of eyes with CRVO achieving an improvement in visual acuity of three or more lines was 45% after treatment with rt-PA and 21% after hemodilution therapy. The median final best-corrected visual acuity among CRVO patients given rt-PA was 20/60 (light perception, 20/15) compared with 20/400 (light perception, 20/20) in the hemodilution group. There were no significant differences among patients with branch retinal vein occlusion (n = 11). We observed no serious adverse events. No significant differences were found regarding the development of ocular neovascularization. CONCLUSION: Treatment with intravenous low-dose rt-PA improved visual outcome in CRVO. Thrombolysis was not associated with a lower risk of ocular neovascularization, indicating that the mechanisms involved in this process occur at an early stage.