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Mehrdad Mohammadpour,1 Mehdi Mazloumi,2 Masoud Khorrami-Nejad1,3 1Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran; 2Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA, USA; 3School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, IranCorrespondence: Mehdi MazloumiWills Eye Hospital, Thomas Jefferson University, Philadelphia, PA, USATel +1 2673577861Email mazloumi.mehdi@gmail.comPurpose: To describe a case with acute postoperative uveitis, posterior synechia and iris atrophy following iris-claw phakic intraocular lens (pIOL) implantation.Methods: A case report.Results: A 26-year-old man with high myopia had implantation of a − 14.0 diopter, foldable, iris-claw Artiflex (model 401) anterior chamber pIOL (Ophtec B.V.) in both eyes. On the third postoperative day, the patient had significant postoperative inflammation in the left eye and received topical steroids and mydriatic eye drops. On the fifth postoperative day, the right eye had a round pupil and centered pIOL, but the left eye had an atrophic iris and dilated pupil with significant posterior synechias over the inferior half of the pupil. Despite intensive topical steroid application, the synechias remained one year after surgery.Conclusion: Severe uveitis with posterior synechia can occur after iris-claw pIOL implantation. We hypothesized that excessive iris tissue enclavation in the pIOLs haptics and large iridotomies may be an associated factor.Keywords: phakic intraocular lenses, anterior uveitis, posterior synechia, iris atrophy

Mehrdad Mohammadpour,1 Masoud Khorrami-Nejad1,2 1Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran; 2School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, IranCorrespondence: Masoud Khorrami-NejadEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, IranTel +98 21 5540 0010Email op_khorrami@yahoo.comAbstract: We introduce a simple, easy to learn, fast and safe technique to facilitate nucleus management in patients with zonular weakening in uncomplicated cases. The surgery begins with a temporal 3.2 mm clear corneal incision under topical anesthesia. Two side-port incisions are made on the inferior and superior sides. Anterior continuous curvilinear 5– 6 mm diameter capsulorhexis and hydrodissection are performed to loosen capsule cortical attachments. The nucleus is not rotated, and an appropriated groove (80– 90% depth) is sculpted using phaco machine. The groove is cracked into two hemispheres; lateral pressure and a side port manipulator. Then, 15– 30 degree phaco tip is introduced and embedded into one hemisphere of nucleus beside the capsulorhexis edge at temporal or nasal part. After complete removal of the first hemisphere, the second is flipped again from bag into iris plane and phacoemulsified in the same manner.Keywords: phacoemulsification, pseudoexfoliation syndrome

Mehrdad Mohammadpour, Meysam Kosari, Masoud Khorrami-Nejad Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, IranCorrespondence: Mehrdad MohammadpourEye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, IranTel +98 21 5540 0010Email mahammadpour@yahoo.comPurpose: To report a case of Behcet’s disease presented with bilateral hypopyon after sequential cataract surgery masquerading delayed onset post-operative endophthalmitis.Methods: A 53-year-old man with a history of sequential uneventful cataract surgeries came to our clinic with decreased vision (0.3 LogMAR) since 2 days ago and bilateral hypopyon in his both eyes. The primary diagnosis was chronic late-onset endophthalmitis.Results: There was no lid edema or chemosis on the external examination. On slit-lamp examination, the cornea was clear, the pupil was well reactive with no posterior synechia, the intraocular lens was centered with good red reflex, however, bilateral hypopyon was detected in his both eyes which was more prominent in the left eye. The eyes were fairly calm and absence of vitreous reaction on slit-lamp examination, there was no pain and photophobia. Further, on physical examination, oral mucosal ulcerations were detected. His systemic workup revealed Behcet’s disease with HLA-B5 positive serology.Conclusion: In cases with delayed onset hypopyon following cataract surgery, inflammatory diseases such as Behcet’s disease should be considered. Appropriate history taking and physical examinations in the context of serologic laboratory investigations may lead to the proper diagnosis.Keywords: Behcet’s disease, bilateral hypopyon, uveitis, cataract surgery

We apply the classical finite Fourier transform to construct an embedded functional process to a given multivariate time series model. The basic properties of the embedded functional process are presented. It appears that the embedded functional process is quite useful for the model building and prediction. We also provide a new method for approximating an infinite functional process with a finite functional process. The methodology is different from the classical one. Indeed, the active underlying frequencies are taken into consideration rather than the significant eigenvectors. The performance of our method is illustrated through simulations. Interestingly, in doing prediction, it appears that for our proposal the computation time is much shorter compared to existing ones. [ABSTRACT FROM AUTHOR]

Alternative estimation and forecasting procedures for the integer-valued autoregressive process with dependent geometric counting series are investigated. Some nonparametric estimation methods are applied to estimate the parameters of the model. The performance of the estimators is assessed via simulation study. We investigate an application of the process using COVID-19 data set and illustrate the best performance of the proposed model among some competitive INAR(1) models via the residual analysis and model adequacy. Consequently, the selected model is applied to predict the number of cases of COVID-19 based on the classic and Bayesian approaches. [ABSTRACT FROM AUTHOR]

Mehrdad Mohammadpour,1 Seyedeh Simindokht Hosseini,1 Masoud Khorrami-Nejad,1,2 Fatemeh Bazvand1 1Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran; 2Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran Abstract: Microbial keratitis is a potentially blinding condition for those who do not receive rapid and proper treatment. The case of a healthy 26-year-old man who has worn extended-wear hydrogel soft contact lenses and developed a unilateral central corneal ulcer with underlying dense stromal infiltrates surrounded by subepithelial and superficial stromal opacity in a reticular pattern along with several complications is reported. Keywords: infectious keratitis, contact lens, emergency penetrating keratoplasty

Mehrdad Mohammadpour,1 Mehdi Khodaparast,1 Masoud Khorrami-Nejad1,21Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran; 2Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, IranIntroduction: We report a case of a 35-year-old man who presented with headache followed by decreased vision, metamorphopsia, and altered color perception in his left eye, after repeated intake of sildenafil citrate (four times; 100 mg) in a limited period (3 days).Methods: On the first ocular examination, best-corrected distance visual acuity (CDVA) was 20/80 in his left eye and 20/20 in his right eye. On fundus examination, loss of foveal reflex and serous retinal detachment in the foveal region were detected. Fluorescein angiography of the left eye was compatible with a leakage area with determined borders. The patient was advised to stop sildenafil intake.Results: After 4 weeks, CDVA increased to 20/25, and the fundus examination revealed significant improvement of the macular edema. Optical coherence tomography showed increased foveal thickness to 350 μm.Conclusion: Advising patients with central serous chorioretinopathy to stop sildenafil intake should be considered.Keywords: central serous chorioretinopathy, sildenafil citrate, serous retinal detachment

Parabolic carrier Pulse Width Modulation (PWM) method is considered as one of the direct current control methods for the Voltage Source Converters (VSCs). This method has an excellent dynamic response. Besides, it offers a constant switching frequency by employing a pair of parabolic PWM carriers. However, it suffers from some drawbacks and limitations. The major drawback of this method is its sensitivity to the inductance variations. In other words, in grid-connected applications, the exact value of grid inductance should be known to achieve a proper performance. Moreover, it is essential that during each switching cycle, the voltage at the point of common coupling remains constant. In grid connected applications such as active power filter, these drawbacks may lead to operation at variable or non-expected frequencies. Therefore, this paper provides suggestions to deal with the situation. In this paper, by applying the conventional method, the aforementioned problems are examined in a grid-connected active power filter. It is shown analytically that by using the proposed method, the problem of sensitivity to inductance is overcome and the necessity for a constant voltage at the point of common coupling in a switching period will be solved as well. The simulation and experimental results are presented. [ABSTRACT FROM AUTHOR]