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Neuroophthalmic manifestations are very rare in corona virus disease-19 (COVID-19) infection. Only few reports have been published till date describing COVID-19-associated neuroophthalmic manifestations. We, hereby, present a series of three cases who developed optic neuritis during the recovery period from COVID-19 infection. Among the three patients, demyelinating lesions were identified in two cases, while another case was associated with serum antibodies against myelin oligodendrocyte glycoprotein. All three patients received intravenous methylprednisolone followed by oral steroids according to the Optic Neuritis Treatment Trail ptotocol. Vision recovery was noted in all three patients, which was maintained at 2 months of the last follow up visit.

Phacoemulsification in soft cataracts can be challenging due to the lack of rigid cleavage planes and the inability to crack. We describe a new phacoemulsification technique for dealing with soft cataracts using high vacuum and zero energy. Following capsulorhexis and hydrodissection, we introduced the phacoemulsification probe, keeping the torsional and longitudinal power at zero. A central groove was created in sculpting mode. We held the nucleus with adequate vacuum in chop mode and divided the nucleus. Then, we rotated and chopped the nucleus similarly into small pieces without using any power. For emulsification, we increased the vacuum to 600 mmHg and then shredded and stuffed the pieces into the phaco probe by the chopper. A newer generation phaco machine with active fluidic system and monitored pressurized infusion helps the surgeon control the intraocular pressure (IOP) and hold the nucleus with vacuum alone, allowing chopping and emulsifying of the pieces without any energy.

Filling-in at the blind spot is a perceptual phenomenon in which the visual system fills the informational void, which arises due to the absence of retinal input corresponding to the optic disc, with surrounding visual attributes. It is known that during filling-in, nonlinear neural responses are observed in the early visual area that correlates with the perception, but the knowledge of underlying neural mechanism for filling-in at the blind spot is far from complete. In this work, we attempted to present a fresh perspective on the computational mechanism of filling-in process in the framework of hierarchical predictive coding, which provides a functional explanation for a range of neural responses in the cortex. We simulated a three-level hierarchical network and observe its response while stimulating the network with different bar stimulus across the blind spot. We find that the predictive-estimator neurons that represent blind spot in primary visual cortex exhibit elevated non-linear response when the bar stimulated both sides of the blind spot. Using generative model, we also show that these responses represent the filling-in completion. All these results are consistent with the finding of psychophysical and physiological studies. In this study, we also demonstrate that the tolerance in filling-in qualitatively matches with the experimental findings related to non-aligned bars. We discuss this phenomenon in the predictive coding paradigm and show that all our results could be explained by taking into account the efficient coding of natural images along with feedback and feed-forward connections that allow priors and predictions to co-evolve to arrive at the best prediction. These results suggest that the filling-in process could be a manifestation of the general computational principle of hierarchical predictive coding of natural images.

Patients under hemolytic condition need continuous monitoring of lysis as depletion of Red Blood Cells (RBC) and the presence of antioxidant free hemoglobin (Hb) in excess amount due to hemolysis lead to severe deterioration of their health. Out of many modalities, Photoacoustics (PA) offers real time information noninvasively from deep lying blood vessels since Hb is the strongest chromophore in mammalian blood and the PA response of blood varies with the amount of Hb present. During hemolysis, total Hb content in blood however remains unchanged, thus, questions the use of PA in hemolysis detection. In this report, a hypothesis that the amplitude of the PA signal would not change with the amount of lysis is framed and tested by applying osmotic shock to the RBCs in hypotonic environment and the PA response is recorded over time using a low cost NIR based PA system. The experimental outcome indicates that PA amplitude falls off as lysis progresses in course of time consequently rejecting the hypothesis. The decaying PA response also carries the signature of RBC swelling during the early phase of lysis. The PA measurement can detect hemolysis as low as 1.7%. These findings further advocate transforming this NIR-PA system into a portable, noninvasive patient care device to monitor hemolysis in-vivo.

Purpose: To evaluate the clinical outcome following intraoperative transzonular intravitreal injection of triamcinolone acetonide and moxifloxacin in patients undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation. Methods: In this prospective, non-randomized, clinical, interventional study, a total of 200 eyes were enrolled. Patients who voluntarily gave their consent after being informed about dropless cataract surgery along with its pros and cons were included. Those who had glaucoma or were known steroid responders as well as those who were lost to follow-up were excluded. 0.1 ml each of moxifloxacin (500 mg) and triamcinolone acetonide (4 mg) were injected transzonularly following IOL implantation in phacoemulsification cataract surgery with the help of 27G curved cannula. Slit-lamp examination was done to detect cells, visual acuity was noted, and intraocular pressure was measured postoperatively on day 1, 7, 30, 60, and 90. Results: Uncorrected visual acuity (UCVA) greater than 6/9 was achieved in 96% of patients at the end of 3 months. The mean IOP was found to be normal in all the cases at every visit. Twenty patients complained of floaters on postoperative day 1 (D1), which decreased to zero after 60 days (D60). None of the patients needed any eye drop during the entire postoperative period. Conclusion: The study demonstrates that this procedure is advantageous and safe.

The partial dominance orderings introduced in Allison and Foster (J.Health Econom. 23 (3), 505–524, 2004 ) and Chakravarty and Maharaj (Int. J. Econom. Theory 11 (2), 231–246, 2015 ) are applicable to ordinal variables with identical median categories. In the present paper, we extend these approaches to distributions having different medians. We introduce the notions of “ Slide ” and “ Addition of Unpopulated Categories at Extremities ”(AUCE) and construct new distributions with matching median categories from distributions having non-identical medians. In general, these two notions are sufficient to generate distributions with matching median categories and in some cases, Slide alone suffices. If both Slide and AUCE are required to generate the new distributions, then these distributions may not be ranked by the dominance ordering of Allison and Foster but may be ranked by that of Chakravarty and Maharaj. On the other hand, if Slide alone is used, then the generated distributions may be ranked by both criteria. We characterize the class of polarization measures that ranks the original distributions in accordance with the dominance orderings of the constructed distributions. We observe that a number of well-known polarization measures belongs to this class. Empirical applicability of the theory is illustrated using data on male and female educational attainments in India.

Psychophysical experiments reveal our horizontal preference in perceptual filling-in at the blind spot. On the other hand, tolerance in filling-in exhibit vertical preference. What causes this anisotropy in our perception? Building upon the general notion that the functional properties of the early visual system are shaped by the innate specification as well as the statistics of the environment, we reasoned that the anisotropy in filling-in could be understood in terms of anisotropy in orientation distribution inherent in natural scene statistics. We examined this proposition by investigating filling-in of bar stimuli in a Hierarchical Predictive Coding model network. The model network, trained with natural images, exhibited anisotropic filling-in performance at the blind spot, which is similar to the findings of psychophysical experiments. We suggest that the over-representation of horizontal contours in the natural scene contributes to the observed horizontal superiority in filling-in and the broader distribution of vertical contours contributes to the observed vertical superiority of tolerance in filling-in. These results indicate that natural scene statistics plays a significant role in determining the filling-in performance at the blind spot and shaping the associated anisotropies.