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Time and polarization-resolved stimulated emission depletion (STED) measurements are used to investigate excited state evolution following the two-photon excitation of enhanced green fluorescent protein (EGFP). We employ a new approach for the accurate STED measurement of the hitherto unmeasured degree of hexadecapolar transition dipole moment alignment α40 present at a given excitation-depletion (pump-dump) pulse separation. Time-resolved polarized fluorescence measurements as a function of pump-dump delay reveal the time evolution of α40 to be considerably more rapid than predicted for isotropic rotational diffusion in EGFP. Additional depolarization by homo-Förster resonance energy transfer is investigated for both α20 (quadrupolar) and α40 transition dipole alignments. These results point to the utility of higher order dipole correlation measurements in the investigation of resonance energy transfer processes.

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In this work, we present a complete theoretical description of the excited state order created by two-photon photoselection from an isotropic ground state; this encompasses both the conventionally measured quadrupolar (K = 2) and the "hidden" degree of hexadecapolar (K = 4) transition dipole alignment, their dependence on the two-photon transition tensor and emission transition dipole moment orientation. Linearly and circularly polarized two-photon absorption (TPA) and time-resolved single- and two-photon fluorescence anisotropy measurements are used to determine the structure of the transition tensor in the deprotonated form of enhanced green fluorescent protein. For excitation wavelengths between 800 nm and 900 nm, TPA is best described by a single element, almost completely diagonal, two-dimensional (planar) transition tensor whose principal axis is collinear to that of the single-photon S0 → S1 transition moment. These observations are in accordance with assignments of the near-infrared two-photon absorption band in fluorescent proteins to a vibronically enhanced S0 → S1 transition.

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A new approach to time-resolved fluorescence spectroscopy based on stimulated emission depletion (STED) of two-photon excited states is presented. Combined with time-resolved detection, STED can circumvent orientational averaging constraints and spontaneous emission selection rules inherent in all conventional techniques. Applications of STED to the study of molecular probe dynamics are presented, together with studies of STED dynamics in a new push-push two-photon chromophore.

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Twenty eyes with age related peripapillary choroidal neovascular membranes were studied retrospectively to establish visual outcome in relation to treatment with argon laser, position and size. There was no statistical difference in final visual acuity in relation to laser treatment, size of membrane, nor position of the membrane at presentation. Despite these findings, there is evidence that laser treatment may delay the progression of visual loss.

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The role of oral acyclovir (ACV) in the management of immunocompetent patients with herpes zoster ophthalmicus remains controversial. We have performed a retrospective, comparative, case-control study of cases seen in the Zoster Clinic at Moorfields Eye Hospital over the last 5 years. A standard proforma was used during this period to collect data on the rash, ocular involvement and treatment. There were 419 immunocompetent patients of whom 77 were treated with oral ACV prior to attending the clinic. We compared these with paired controls matched for age, sex and severity of rash. No difference in the rate of ocular complications between treated and untreated patients could be detected. This suggests that oral ACV as currently prescribed has little or no preventive effect on the ocular complications of ophthalmic zoster.

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Six double-blind, independently randomized studies evaluated the efficacy and safety of calcium mupirocin ointment in eliminating nasal carriage of Staphylococcus aureus among health care workers. Healthy volunteers with stable nasal carriage of S. aureus (n = 339) received either calcium mupirocin ointment (n = 170) or an identical placebo ointment (n = 169) intranasally for 5 days. Nasal carriage was eliminated 48-96 hours after completion of treatment in 130 (91%) of 143 evaluable volunteers receiving mupirocin but in only 8 (6%) of 142 evaluable volunteers receiving placebo. The 85% crude difference represents a 90% pooled (adjusted) estimate of the risk difference (95% confidence interval, 0.86-0.95) and a risk ratio of 16 (P < .0001). This effect of treatment with mupirocin was observed consistently (risk ratio, 8-32) in all six centers. In addition, 96 of the 130 mupirocin-treated volunteers and 1 of the 8 placebo-treated volunteers who were culture-negative at the end of therapy remained free of S. aureus 4 weeks after treatment. Adverse events in each treatment arm were mild and equally frequent. These data, consistent across six institutions, demonstrate that calcium mupirocin ointment administered intranasally for 5 days is safe and effective in eliminating stable nasal carriage of S. aureus.

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A current review of ophthalmic zoster is presented including its virology, immunology, epidemiology and pathogenesis. We give our findings in 1356 patients referred to the Zoster Clinic at Moorfields Eye Hospital, London. The treatment of the disease and its ocular complications is discussed.

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Ninety seven new patients with ophthalmic zoster were randomly allocated to three topical treatment groups: acyclovir (ACV) ointment and placebo drops (AP), placebo ointment with steroid drops (PS), and acyclovir ointment with steroid drops (AS). The dosage administered was determined by the score of the ocular inflammation. Follow-up was for at least one year. The results showed that topical ACV alone is insufficient for severe ocular inflammation but is not inclined to lead to recurrences in milder cases. Topical steroid alone is effective but tends to necessitate prolonged treatment. Combined steroid and ACV is questionably better than steroid alone and causes marginally fewer rebound inflammations.

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We describe the results and the complications encountered in 69 lensectomies performed via a limbal approach with the Ocutome vitrectomy instrument, in which it was the intention at surgery to maintain the integrity of the posterior capsule. After operation 87% improved in visual acuity, and 68% achieved 6/12 or better. The main early complications encountered were perioperative rupture of the posterior capsule and iris damage. The main late complications were postoperative thickening of the posterior capsule, retinal detachment, and bullous keratopathy. Of the eyes in which the posterior capsule remained intact after operation 17% developed thickening of the posterior capsule to a degree that required capsulotomy over a mean follow-up period of 50 months.

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Most ophthalmic zoster occurs in healthy people and ocular complications occur in 50%. The mainstay of ocular therapy is topical steroid, but careful follow-up and withdrawal are essential. The place of systemic steroid therapy and acyclovir in immunocompetent patients with zoster is uncertain.

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A description is given of the apparatus and technique for carrying out cine photography of anterior segment fluorescein angiography with special emphasis on its application in the recording and diagnosis of iris tumours.

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Between 40-94% of patients with florid AIDS develop ocular complications indeed, these may be the presenting feature of the disease. They fall into four categories: primary retinal microvascular disease; opportunistic infections of the eye and adnexa; neoplasms of the eye and adnexa; and neurophthalmic abnormalities.

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Surgical outcome after ophthalmic zoster was analysed with respect to cataract, glaucoma, corneal ulceration and scarring. We used data from the Zoster Clinic and Hospital Activity Analysis (HAA) at Moorfields Eye Hospital and a lipid keratopathy database at the Western Ophthalmic Hospital. Conventional surgery for cataract, glaucoma and corneal scarring gave good results which were probably no different from experience with routine cases, although there was a tendency for prolonged post-operative inflammation. Lateral and central tarsorrhaphy for neuroparalytic ulceration almost invariably led to rapid healing.

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Sixty-three cases of vascularised lipid keratopathy were treated with the argon laser to occlude feeder vessels which had been identified by fluorescein angiography. There was a reduction in extent in 62% and density in 49%. Visual acuity was improved in 48%. Six patients had keratoplasties shortly after treatment, none of which showed graft rejection. Minor complications included temporary haemorrhage into the cornea and iris atrophy. A more serious problem was severe corneal thinning after resorption of lipid. The patients had to be carefully followed up and maintained on a low dose of topical steroid.

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A retrospective analysis of 32 cases of anterior uveal melanocytic tumours included 14 cases in which the tumours could be categorised histologically as malignant, of intermediate cytology with equivocal features of malignancy, or as benign progressive naevi. An additional eight cases without a histological diagnosis were included as benign naevi, because there had been no change in their clinical characteristics after a minimum follow-up of four years. Clinical features and iris fluorescein angiographic (IFA) findings were analysed with respect to these groups in an attempt to identify features predictive of malignant or locally invasive behaviour. Very small tumours were more likely to be benign (p = 0.029). Glaucoma and episcleral vascular dilatation occurred in ciliary body tumours only. Tumours involving the anterior chamber angle proved more likely to be malignant (p = 0.019). IFA showed a disorganised vasculature and gross late leakage in 4/7 (56%) malignant melanomas as well as in 2/6 (33%) tumours with intermediate cytology. No benign tumours showed these features. Four out of nine (44%) benign tumours, but no tumours with malignant or intermediate cytology, showed complete masking of fluorescence. Early leakage of dye from tumour vessels and a geometric tumour vasculature were not specific features of any tumour category. IFA correlated with the cytology and behaviour of anterior uveal melanocytic tumours in 11/22 (50%) of our cases.

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We studied 40 patients with a total of 44 retinal arterial macroaneurysms. All patients were followed up for at least six months. Macroaneurysms (MAs) have variable clinical presentations and are still frequently misdiagnosed before fluorescein angiography. Haemorrhagic MAs were most frequently misdiagnosed (75%), and had a sudden onset with a relatively poor visual outcome. Patients with these MAs had higher systolic blood pressures and significantly fewer associated retinal vein occlusions (p less than 0.05) than other types of MA. Exudative MAs caused a gradual onset of symptoms, were frequently associated with retinal vein occlusions, and were the most frequent indication for laser treatment. Only one of 10 quiescent MAs subsequently developed significant exudation or haemorrhage. We confirm the association of MAs with retinal and systemic vascular disease. In addition we found that MA patients had a significantly higher blood packed cell volume (haematocrit) than controls (p less than 0.05). Laser treatment significantly shortened the duration of MA patency (p = 0.006).

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