Author's Reply: Involvement of the Abducens Nucleus Results in Adduction Impairment of the Contralateral Eye

In this report, we provide the first characterization of abducens nucleus neuron (ABN) discharge dynamics during horizontal disjunctive saccades. These movements function to rapidly transfer the visual axes between targets located at different eccentricities and depths. Our primary objective was to determine whether the signals carried by ABNs during these movements are appropriate to drive the motion of the eye to which they project. We also asked whether ABNs encode eye movements similarly during disjunctive saccades and disjunctive fixation. To address the first objective we 1) assessed whether we could predict the discharge dynamics of individual neurons during disjunctive saccades based on their discharge properties during conjugate saccades and 2) directly estimated the sensitivity of individual neurons to either the ipsilateral/contralateral eye or the conjugate/vergence position and velocity using bootstrap statistics. Our main finding was that during disjunctive saccades in the direction ipsilateral to the recording site (on-direction), the majority of ABNs preferentially encoded the velocity and the position of the ipsilateral eye. The remaining neurons predominantly encoded the conjugate motion of the eyes (i.e., were equally sensitive to the motion of both eyes). Generally, ipsilateral/contralateral eye based models better described neuronal discharges than conjugate/vergence based models, yet both model structures yielded similar conclusions. Moreover, the preferred eye of individual neurons based on their position and velocity sensitivities were generally well matched. We also found that for saccades in the off-direction, the pausing behavior of ABNs was similar during conjugate and disjunctive saccades, with the exception that for movements of small amplitudes, more ABNs paused during conjugate saccades. Finally, we found that putative motoneurons and internuclear neurons encoded on- and off-direction disjunctive saccades in a similar manner. To address our second objective, we compared the discharge properties of individual ABNs during disjunctive saccades and disjunctive fixation. Good coherence was observed between the preferred eye of individual ABNs during the two behaviors. Taken together, our results indicate that although individual ABNs can encode the motion of both eyes to various degrees, the population drive of ABNs accounts for most of the movement of the ipsilateral eye during disjunctive saccades and disjunctive fixation.

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Effectiveness of 0.66% Povidone-Iodine Eye Drops on Ocular Surface Flora before Cataract Surgery: A Nationwide Microbiological Study

Journal of Clinical Medicine ◽

10.3390/jcm10102198 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2198

Author(s):

Rosario Musumeci ◽

Pasquale Troiano ◽

Marianna Martinelli ◽

Matteo Piovella ◽

Claudio Carbonara ◽

...

Keyword(s):

Cataract Surgery ◽

Ocular Surface ◽

Povidone Iodine ◽

Bacterial Species ◽

Bacterial Flora ◽

Bacterial Load ◽

Controlled Study ◽

Eye Drops ◽

Microbiological Analysis ◽

Contralateral Eye

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure.

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Chemically-Boosted Corneal Cross-Linking for the Treatment of Keratoconus through a Riboflavin 0.25% Optimized Solution with High Superoxide Anion Release

Journal of Clinical Medicine ◽

10.3390/jcm10061324 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1324

Author(s):

Cosimo Mazzotta ◽

Marco Ferrise ◽

Guido Gabriele ◽

Paolo Gennaro ◽

Alessandro Meduri

Keyword(s):

Superoxide Anion ◽

Hydroxypropyl Methylcellulose ◽

Anterior Segment ◽

Preclinical Study ◽

Cross Linking ◽

Specular Microscopy ◽

The Novel ◽

Power Setting ◽

Contralateral Eye

The purpose of this study was to evaluate the effectiveness and safety of a novel buffered riboflavin solution approved for corneal cross-linking (CXL) in progressive keratoconus and secondary corneal ectasia. Following the in vivo preclinical study performed on New Zealand rabbits comparing the novel 0.25% riboflavin solution (Safecross®) containing 1% hydroxypropyl methylcellulose (HPMC) with a 0.25% riboflavin solution containing 0.10% EDTA, accelerated epithelium-off CXL was performed on 10 patients (10 eyes treated, with the contralateral eye used as control) through UV-A at a power setting of 9 mW/cm2 with a total dose of 5.4 J/cm2. Re-epithelialization was evaluated in the postoperative 7 days by fluorescein dye test at biomicroscopy; endothelial cell count and morphology (ECD) were analyzed by specular microscopy at the 1st and 6th month of follow-up and demarcation line depth (DLD) measured by anterior segment optical coherence tomography (AS-OCT) one month after the treatment. We observed complete re-epithelization in all eyes between 72 and 96 h after surgery (88 h on average). ECD and morphology remained unchanged in all eyes. DLD was detected at a mean depth of 362 ± 50 µm, 20% over solutions with equivalent dosage. SafeCross® riboflavin solution chemically-boosted corneal cross-linking seems to optimize CXL oxidative reaction by higher superoxide anion release, improving DLD by a factor of 20%, without adverse events for corneal endothelium.

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Five year results of a prospective, randomised, contralateral eye trial of corneal crosslinking for keratoconus

Clinical and Experimental Ophthalmology ◽

10.1111/ceo.13959 ◽

2021 ◽

Author(s):

Jay J. Meyer ◽

Charlotte A. Jordan ◽

Dipika V. Patel ◽

Akilesh Gokul ◽

Simon J. Dean ◽

...

Keyword(s):

Corneal Crosslinking ◽

Contralateral Eye

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Chronic Glaucoma Using Biodegradable Microspheres to Induce Intraocular Pressure Elevation. Six-Month Follow-Up

Biomedicines ◽

10.3390/biomedicines9060682 ◽

2021 ◽

Vol 9 (6) ◽

pp. 682

Author(s):

Maria Jesus Rodrigo ◽

David Garcia-Herranz ◽

Manuel Subias ◽

Teresa Martinez-Rincón ◽

Silvia Mendez-Martínez ◽

...

Keyword(s):

Intraocular Pressure ◽

Anterior Chamber ◽

Clinical Signs ◽

Progressive Increase ◽

Biodegradable Microspheres ◽

Fiber Layer ◽

Chronic Glaucoma ◽

Biodegradable Poly ◽

Contralateral Eye

Background: To compare two prolonged animal models of glaucoma over 24 weeks of follow-up. A novel pre-trabecular model of chronic glaucoma was achieved by injection of biodegradable poly lactic-co-glycolic acid (PLGA) microspheres (10–20 µm) (Ms20/10) into the ocular anterior chamber to progressively increase ocular hypertension (OHT). Methods: Rat right eyes were injected to induce OHT: 50% received a suspension of Ms20/10 in the anterior chamber at 0, 2, 4, 8, 12, 16 and 20 weeks, and the other 50% received a sclerosing episcleral vein injection biweekly (EPIm). Ophthalmological clinical signs, intraocular pressure (IOP), neuroretinal functionality measured by electroretinography (ERG), and structural analysis of the retina, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) protocols using optical coherence tomography (OCT) and histological exams were performed. Results: Both models showed progressive neuroretinal degeneration (p < 0.05), and contralateral eye affectation. The Ms20/10 model showed a more progressive increase in IOP and better preservation of ocular surface. Although no statistical differences were found between models, the EPIm showed a tendency to produce thicker retinal and thinner GCL thicknesses, slower latency and smaller amplitude as measured using ERG, and more aggressive disturbances in retinal histology. In both models, while the GCL showed the greatest percentage loss of thickness, the RNFL showed the greatest and earliest rate of thickness loss. Conclusions: The intracameral model with biodegradable microspheres resulted more like the conditions observed in humans. It was obtained by a less-aggressive mechanism, which allows for adequate study of the pathology over longer periods.

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Development of the human abducens nucleus: A morphometric study

Brain and Development ◽

10.1016/j.braindev.2011.12.009 ◽

2012 ◽

Vol 34 (9) ◽

pp. 712-718 ◽

Cited By ~ 7

Author(s):

Katsuyuki Yamaguchi ◽

Koichi Honma

Keyword(s):

Morphometric Study ◽

Abducens Nucleus

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Unilateral paralysis of conjugate gaze due to lesion of the abducens nucleus Clinico-pathological case report

Neuro-Ophthalmology ◽

10.3109/01658108109010259 ◽

1981 ◽

Vol 2 (1) ◽

pp. 47-52 ◽

Cited By ~ 9

Author(s):

Ottmar Meienberg ◽

Jean A. Ner-Enneve ◽

Rolf Kraus-Ruppert

Keyword(s):

Case Report ◽

Abducens Nucleus ◽

Pathological Case

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Pupil Dilation with Intracameral Epinephrine Hydrochloride during Phacoemulsification and Intraocular Lens Implantation

Journal of Ophthalmology ◽

10.1155/2016/4917659 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

A-Yong Yu ◽

Hua Guo ◽

Qin-Mei Wang ◽

Fang-Jun Bao ◽

Jing-Hai Huang

Keyword(s):

Intraocular Lens ◽

Pupil Diameter ◽

Pupil Dilation ◽

Surgical Performance ◽

Corneal Incision ◽

Iol Implantation ◽

The Mean ◽

Contralateral Eye ◽

To Receive ◽

Time Point

Objective. To investigate mydriatic effect of intracamerally injected epinephrine hydrochloride during phacoemulsification and intraocular lens (IOL) implantation.Methods. Eighteen cataract patients for bilateral phacoemulsification were enrolled. To dilate pupil, one eye was randomly selected to receive intracamerally 1 mL epinephrine hydrochloride 0.001% for 1 minute after corneal incision (intracameral group), and the contralateral eye received 3 drops of compound tropicamide 0.5% and phenylephrine 0.5% at 5-minute intervals 30 minutes before surgery (topical group). Pupil diameters were measured before corneal incision, before ophthalmic viscoelastic device (OVD) injection, after OVD injection, before IOL implantation, and at the end of surgery.Results. At each time point, the mean pupil diameter in the intracameral group was2.20±0.08,5.09±0.20,6.76±0.19,6.48±0.18, and5.97±0.24 mm, respectively, and in the topical group it was7.98±0.15,7.98±0.15,8.53±0.14,8.27±0.16, and7.93±0.20 mm, respectively. The topical group consistently had larger mydriatic effects than the intracameral group (P<0.05). The onset of mydriatic effect was rapid in the intracameral group. There was no difference in surgical performance or other parameters between groups.Conclusions. Intracameral epinephrine hydrochloride appears to be an alternative to the mydriatic modalities for phacoemulsification and IOL implantation. In comparison with topical mydriatics, intracameral epinephrine hydrochloride offers easier preoperative preparation, more rapid pupil dilation, and comparable surgical performance.

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