Circuit Complexity of Visual Search

We study computational hardness of feature and conjunction search through the lens of circuit complexity. Let $x = (x_1, ... , x_n)$ (resp., $y = (y_1, ... , y_n)$) be Boolean variables each of which takes the value one if and only if a neuron at place $i$ detects a feature (resp., another feature). We then simply formulate the feature and conjunction search as Boolean functions ${\rm FTR}_n(x) = \bigvee_{i=1}^n x_i$ and ${\rm CONJ}_n(x, y) = \bigvee_{i=1}^n x_i \wedge y_i$, respectively. We employ a threshold circuit or a discretized circuit (such as a sigmoid circuit or a ReLU circuit with discretization) as our models of neural networks, and consider the following four computational resources: [i] the number of neurons (size), [ii] the number of levels (depth), [iii] the number of active neurons outputting non-zero values (energy), and [iv] synaptic weight resolution (weight). We first prove that any threshold circuit $C$ of size $s$, depth $d$, energy $e$ and weight $w$ satisfies $\log rk(M_C) \le ed (\log s + \log w + \log n)$, where $rk(M_C)$ is the rank of the communication matrix $M_C$ of a $2n$-variable Boolean function that $C$ computes. Since ${\rm CONJ}_n$ has rank $2^n$, we have $n \le ed (\log s + \log w + \log n)$. Thus, an exponential lower bound on the size of even sublinear-depth threshold circuits exists if the energy and weight are sufficiently small. Since ${\rm FTR}_n$ is computable independently of $n$, our result suggests that computational capacity for the feature and conjunction search are different. We also show that the inequality is tight up to a constant factor if $ed = o(n/ \log n)$. We next show that a similar inequality holds for any discretized circuit. Thus, if we regard the number of gates outputting non-zero values as a measure for sparse activity, our results suggest that larger depth helps neural networks to acquire sparse activity

Perspectives on the role of orthoptists in Japan

The authors summarized history of orthoptists. Demand for orthoptists in ophthalmology is on the increase. However it was revealed a shortage in the number of orthoptists. If awareness of orthoptists is increased, it is expected that the number of students wishing to become orthoptists will increase, leading to a growth in those qualified in orthoptists, thus making a contribution to ophthalmology. A greater variety of PR activities are required in order to increase awareness

Evaluation of the relationship between quality of vision and visual function in Japanese glaucoma patients

Hideko Sawada, Takeo Fukuchi, Haruki AbeDepartment of Ophthalmology, Niigata University Medical and Dental Hospital, Niigata, JapanPurpose: To evaluate the correlation between quality of vision (QOV) and visual function in glaucoma patients.Patients and methods: The relationship between QOV and visual function was investigated in 200 Japanese glaucoma patients. QOV was assessed using the Japanese version of the 25-item National Eye Institute Visual Function Questionnaire. The better eye and the worse eye were defined based on the mean deviation (MD) value of the Humphrey Field Analyzer program 30-2. A single linear regression analysis was applied to assess the relationship.Results: The lowest subscale score was observed in general health followed by general vision and driving. Visual acuity and the central 10° MD value in the better eye and the central 30° MD value in the worse eye were highly correlated with QOV. Threshold MD values at which patients began to have lower QOV ranged from —2 to —12 dB in the better eye and from —7 to —16 dB in the worse eye.Conclusion: Loss of visual function in both the better and the worse eye is significantly correlated to QOV. QOV of glaucoma patients begins to decrease in the early stages of visual field defects.Keywords: glaucoma, 25-item National Eye Institute Visual Function Questionnaire, visual field, visual acuity, quality of visio

Fibrin membrane pupillary-block glaucoma after uneventful cataract surgery treated with intracameral tissue plasminogen activator: a case report

<p>Abstract</p> <p>Background</p> <p>Fibrin pupillary-block glaucoma is a rare complication after cataract surgery. The treatment for this condition is still controversial, since Nd:YAG laser fibrin membranotomy tends to reocclude and laser peripheral iridotomy entails the risk of damaging the corneal endothelium in the presence of corneal edema associated with elevated intraocular pressure.</p> <p>Case presentation</p> <p>A 62-year-old man with diabetes mellitus developed acute elevation of intraocular pressure with a shallow anterior chamber five days after uneventful cataract surgery. Initially, slit lamp examination provided only limited information due to severe corneal edema. After resolution of corneal edema with systemic glaucoma therapy, a complete fibrin membrane was observed across the pupil by slit lamp examination. Anterior segment optic coherence tomography clearly revealed a thin fibrin membrane covering the entire pupillary space, a shallow anterior chamber, and a deep posterior chamber. The intraocular lens was not observed by anterior segment optic coherence tomography. In contrast, ultrasound biomicroscopy, which has superior penetration depth, was able to visualize the intraocular lens deep in the posterior chamber. Injection of tissue plasminogen activator into the anterior chamber resulted in complete fibrinolysis and released the pupillary block.</p> <p>Conclusion</p> <p>This case suggests that ocular anterior segment imaging modalities, especially ultrasound biomicroscopy, serve as powerful diagnostic tools to identify mechanisms of acute angle closure glaucoma, which is often accompanied by poor intraocular visibility. This is the first reported case of fibrin pupillary-block glaucoma after cataract surgery successfully treated with intracameral tissue plasminogen activator.</p