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Purpose: To describe a strategy to reduce Covid-19 spread among healthcare workers and provide ophthalmologists with recommendations useful for a possible second wave of Covid-19 in Autumn. Methods: Epidemiological surveillance at the Cà Foncello Hospital (Veneto, Italy) since 24 February 2020 to 24 April 2020 when the municipality of Treviso was hit by the Covid-19 outbreak. The number of naso-pharigeal (NP) swabs performed was 7010. Results: The number of infected among healthcare workers was 209/ 3924 (5.32%): medical doctors: 28 cases / 498 (5.6%). None among ophthalmologists; specialized nurses: 86/1294 (6.4%) None in the ophthalmic unit; intermediate care technicians: 68/463 (14.7%). The 46% of the positive tested were asymptomatic. We share key suggested actions for the reorganization in ophthalmological services: be part of a global epidemiological local strategy of containment (Testing, Tracing, Treating); protect your department: Keep on screening patients by telephone interview before entering the hospital; promote continuous and appropriate use of PPE both for doctors and for patients; make any effort to obtain a continuous flow of patients in every line of the ophthalmic service; treat appropriately any single patient with vision threatening condition; avoid unnecessary or futile testings and examinations. Conclusion: The Treviso model shows that it is possible and safe to keep on performing high risk hospital activities like ophthalmology, even in the epicenter of covid outbreak, if adequate actions are performed. We discuss about the value of NP swabs and serological tests as a strategy in case of a second wave of infections.

Purpose: To compare the effect of topical 0.1% indomethacin solution versus 0.1% fluorometholon acetate in the early postoperative period after LASEK treatment. Methods: One hundred thirty-five patients undergoing LASEK, having been randomized in a double-masked manner into 2 groups (1 receiving indomethacin and 1 fluorometholon), were evaluated 2–4 days before and 4 days after treatment. We examined corneal fluorescein staining and corneal esthesiometry; the level of pain experienced was reported by the patient on a visual pain scale. In addition, haze was evaluated at 14 ± 1 weeks after surgery. Results: The pain level and corneal fluorescein staining were significantly less in the indomethacin group. Corneal esthesiometry was reduced to the same extent in the 2 groups. There were no statistically significant differences in haze presentation between the 2 groups. Conclusion: Our study highlights the efficacy of indomethacin solution compared with fluorometholon as a pain reducer after LASEK treatment and suggests that indomethacin is associated with a faster epithelial healing process.

The signal structure of the responses to equiluminant chromatic and achromatic (contrast) stimuli was studied in normal volunteers and patients with mild to moderate idiopathic Parkinson's disease. Visual stimuli were full-field (14 x 16 deg) achromatic or equiluminant (red-green or blue-yellow) sinusoidal gratings at 2c/deg and 90% contrast presented in onset-offset mode. The signal was processed offline by DFT and factor analysis was performed in the frequency domain. The conventional VEPs to chromatic onset stimuli showed a monophasic negative wave, while the response to offset stimuli was comparable in shape to the on-/offset achromatic responses; latencies were longer and amplitudes higher than those of responses to contrast stimulation. In patients, latencies were longer than in controls after achromatic and (to a lesser extent) red-green stimulations, but not after blue-yellow stimulation; amplitudes were comparable in all stimulus conditions. In healthy subjects, two non-overlapping factors accounted for the approximately 2-30.0 Hz and approximately 25.0-50.0 Hz signal components (representative of the low-frequency VEP and gamma oscillatory responses, respectively); the frequency of the approximately 25.0-50.0 Hz factor was lower after color than after contrast stimulation. The same factor structure was identified in patients, but the peak frequency of the factor on gamma activity was higher than in controls and did not vary with color-opponent stimulation. These observations indicate that stimulus-related gamma activity originates in cortex irrespective of the activated (magno-, parvo-, or konio-cellular) visual pathway, consistent with the suggested role in the phase coding of neuronal activities. Some dopaminergic modulation of gamma activity is conceivable.

The flash induced electroretinogram (ERG) and early receptor potential (ERP) were recorded in a population of patients with definite diagnosis of retinitis pigmentosa in the context of a study protocol including a complete diagnostic screening. ERPs were evoked by full-field 20-joule stimuli (5 stimuli at 10 min of interval in dark adaptation); recording was by skin electrodes positioned at the inferior orbital margin; amplifiers were set at 10-10,000 Hz. The flash ERG was absent or markedly abnormal in all cases, even at an early stage of development of the retinitis, while ERPs (with a normal morphology, latency of the R1 component increased and a reduced amplitude compared to normal controls) could be identified unambiguously in all cases. The amplitude reduction was highly correlated with the severity of the disease as determined by kinetic perimetry and fluorangiography.

Human visual-evoked potentials (VEPs) from upper and lower hemifield stimulation are thought to reflect the anatomical and functional differences between the hemiretinas and corresponding visual pathways. Conflicting results have, however, been reported in topographic studies on the putative cortical generators. We have estimated by automatic perimetry (Octopus 2000R, Program 32) and compared the sensitivity thresholds of lower and upper hemifields of the retina in 12 healthy subjects with no history or evidence of visual or neurological diseases. A visual P3 that is linked to cognitive function was recorded in an odd-ball paradigm with presentation of high-contrast checkerboards at two different spatial frequencies at 20 degrees eccentricity in each hemifield. VEP and P3 were recorded at O1 and O2 and at Cz according to the 10/20 international system. Lower sensitivity thresholds were found, and higher VEP and event-related potential (ERP) amplitude values were obtained when stimulating the lower, compared with the upper, visual hemifield. The results are consistent with previous findings and anatomical and physiological evidence in animals and man. Interactions between perceptive process in the visual system and higher cognitive functions are a possible explanation for this finding.

The evaluation of macular function in patients with opacities of the optic media is very difficult.

Early receptor potentials were recorded by skin electrodes positioned at the inferior orbital margin in 32 patients with recent bullous retinal detachments and in nine patients with old, total retinal detachments. Results were compared to those obtained in a normative study performed on 200 healthy subjects. In patients with recent retinal detachments, no significant variations were found with respect to normal subjects. In patients with old retinal detachments, an early receptor potential of decreased amplitude was recorded in only five subjects, while in the other four the trace could not be separated from the noise.

PURPOSE Stimulus-related oscillatory activity above approximately 20 Hz (gamma band) is observed in the firing rate and membrane or field potentials of neurons in the visual cortex of cat and monkey. Cortical mass responses in the same frequency range are evoked in humans by contrast stimulation and proved (partly) independent of conventional VEPs. Visual evoked responses (pattern VEPs) with abnormal waveform (quasi-sinusoidal or with bifid wave P100) are reportedly common in diseases affecting the visual pathways (e.g., multiple sclerosis). Contributions of gamma activity to the distorted VEP waveform are possible if the mechanisms of generation are differentially affected by brain disorders. This hypothesis was investigated in patients with documented impairment of the visual system. METHODS VEPs and oscillatory responses to contrast stimulation (central 9 degrees of visual field; 1.3 to 5.0 cyc/deg; 80% contrast; reversal at 2.13 Hz) were recorded in 765 patients referred for standard visual testing and frequency analyzed. Controls were 40 healthy volunteers. The stimulus conditions and recording procedures replicated previous normative studies on the human oscillatory response. RESULTS Conventional VEPs were replaced by oscillatory responses comparable to those of controls in the unfiltered recordings of 9.8% of examined patients (with postchiasmatic disorders in 59.9% of cases). Signal amplitude in the frequency interval of the VEPs (below approximately 19 Hz) was significantly lower in the frequency spectra of patients than of controls but did not differ in the frequency range above 20 Hz, reflecting the oscillatory response. CONCLUSIONS The human gamma oscillatory response mediating in cortical visual information processing further proved independent of the VEPs. It can contribute to VEP waveform distortion, and its observation in substitution of VEPs should be regarded as an indication of impaired visual pathway function.

Single intramuscular doses of scopolamine and matching placebo were administered to young, healthy, and emmetropic volunteers. Electroretinograms and visual evoked potentials (flash and pattern stimuli) were recorded prior to and 30, 90, and 120 min after administration. The effects of scopolamine at the central nervous system level were monitored also by quantitative electroencephalographic methods. Scopolamine reduced the peak-to-peak amplitude of the late components of the flash-evoked potential without affecting latencies. A decrease of the N75 latency and increment of N175 latency of pattern-evoked potentials were observed without any apparent modification of the amplitude values. These changes were not produced by administering topical cyclopentholate. Electroencephalographic effects were apparent with a longer delay after administration than were those on the visual evoked potentials. No significant modification was observed in the electroretinogram under these recording conditions.

Electroretinograms and retinal oscillatory potentials to full-field flash stimulation were recorded by dermal electrodes in a population of subjects (1 to 84 yrs) balanced for age and sex (119 females, 133 males), without evidence or history of ocular and/or relevant systemic diseases. The electroretinogram latencies and b-wave amplitude increased, while the a-wave amplitude decreased linearly with age. The oscillatory potential amplitude initially increased, to decrease approximately at the age of 50, with an inverted U-shaped distribution.

Two young brothers were bilaterally affected by pigmentary glaucoma and extensive symmetrical changes of the retinal pigment epithelium (RPE). Fundus changes consisted in widespread salt-and-pepper RPE mottling and pigment clumping, sparing only the peripapillary and foveal areas. During the course of 4 years, one of the two patients suffered multiple, recurrent, exudative and hemorrhagic detachments of the RPE that involved the midperiphery and posterior pole. No exudative lesions appeared in the brother. The medical history and systemic laboratory tests were noncontributory in both patients. The ERG was normal and the EOG subnormal. Dark adaptation was delayed and showed an elevation of the scotopic threshold. These cases seem to support the hypothesis that the RPE is also involved in the pigmentary dispersion syndrome. An inherited defect could affect the pigment epithelium in both the anterior and posterior segments of the eye. The multifocal subretinal exudative pattern that occurred in one of our patients has not been previously observed in hereditary disorders of the RPE.