Ramesh Venkatesh

VeriAbs: Verification by Abstraction Competition Contribution

VeriAbs verifies C programs by transforming them to abstract programs. The transformation replaces loops in the original code by abstract loops of small known bounds. Bounded model checkers can then be used to prove properties over such programs. To perform such a transformation, VeriAbs implements i a static value analysis to compute loop invariants, ii abstract acceleration and output abstraction for numerical loops, iii a novel array witness selection for loops that iterate over arrays, and iv an iterative refinement using an enhanced k-induction technique. To find errors, VeriAbs computes bounds of the original loops and then checks for errors within those bounds. VeriAbs can thus prove properties and find errors using bounded model checking. It uses the C Bounded Model Checker CBMC version 5.4 with MiniSat version 2.2.

Optical Coherence Tomography and Autofluorescence Findings in Photic Maculopathy Secondary to Distant Lightning Strike

Comment. In this case, the excimer laser was used in a novel fashion to ablate central corneal tissue where dye had migrated from the previous tattooing procedure 27 years earlier. This procedure allowed for the creation of a precisely circular central clear corneal “pupil,” enhancing both cosmesis and light passage to maximize the patient’s residual vision. We believe that this method offers a simple and effective technique to clear the areas of aberrant dye that is known to migrate over time following corneal tattooing.

Clomiphene citrate-induced visual hallucinations: a case report

BackgroundPolycystic ovary syndrome is a common cause of chronic anovulation and infertility in otherwise healthy fertile couples. Clomiphene citrate is used as a first-line ovulation induction therapy in patients with polycystic ovary syndrome. Clomiphene citrate can cause both systemic and ocular side effects. We report a rare side effect of illusory palinopsias in a patient with polycystic ovary syndrome treated with ovulation induction therapy with clomiphene citrate, and emphasize the need for gynecologists and their patients to be aware of this rare ocular side effect.Case presentationA 30-year-old Asian woman complained of persistent visual afterimages following treatment with 100 mg clomiphene citrate for anovulation. Her symptoms started on the fourth day after commencing the treatment and would last for 5 to 10 minutes. Similar visual symptoms were noted during her second cycle of treatment with clomiphene citrate. The severity of her symptoms reduced following the stoppage of the medication; however, the symptoms have persisted for more than 1 year since she stopped taking the drug.ConclusionsClomiphene citrate can cause disturbing illusory palinopsias. These afterimages persist even after stopping the infertility medication. It is a side effect not frequently seen by gynecologists or ophthalmologists. Gynecologists should make their patients aware of this rare ocular side effect when their patients start treatment with clomiphene citrate for infertility.

Negative pressure pulmonary edema--a life-threatening condition in an eye care setting: a case report.

BackgroundNegative pressure pulmonary edema is a potentially life-threatening complication after general anesthesia in young healthy individuals that results from upper airway obstruction followed by strong inspiratory effort. It is a known complication after nasal or upper airway surgery. Occurrence of such a life-threatening complication in an eye care setting where advanced intensive care is usually lacking is rare.Case presentationA 15-year-old Asian boy presented to our hospital with a penetrating eye injury caused by a pellet. Globe and vitreoretinal exploratory surgery was performed with the patient under general anesthesia. The patient’s postoperative course was uneventful immediately after the procedure, but soon he developed negative pressure pulmonary edema.ConclusionsThis case report highlights the importance of early diagnosis and prompt management of negative pressure pulmonary edema to save the life of the patient. Most ophthalmologic surgeries are performed with the patient under regional anesthesia; very few are done with the patient under general anesthesia. Intensive care facilities are needed in such settings for prompt management of such a serious and rare complication.

Long-term Follow-up and Outcomes in Traumatic Macular Holes

WE READ WITH GREAT INTEREST THE ARTICLE BY MILLER and associates titled ‘‘Long-term Follow-up and Outcomes in Traumatic Macular Holes.’’ In their study, the authors have very clearly mentioned regarding the timing for vitrectomy and the visual outcomes comparing between spontaneous closure and surgical intervention in patients with traumatic macular holes. However, we have a few comments to make. According to Yamashita and associates, pathogenetically there are 2 distinct types of traumatic macular hole formation: 1 type due to primary dehiscence of the fovea, and the other type due to dehiscence of the fovea secondary to persistent vitreofoveal adhesion. The role of the internal limiting membrane in the formation of the traumatic macular hole has not been clearly understood. Further analysis of cases with vitrectomy with and without internal limiting membrane peeling would have helped in understanding the role of internal limiting membrane in the pathogenesis of formation and spontaneous closure of traumatic macular holes. One of the mechanisms for traumatic macular hole closure, as described by Lewis and associates, was the appearance of the epiretinal membrane around the hole. In the current study, 10 of the 11 cases that underwent vitrectomy for macular hole closure had an associated epiretinal membrane. Thus one would interpret that the presence of the epiretinal membrane in traumatic macular

Efficiently Learning Safety Proofs from Appearance as well as Behaviours

Proving safety of programs relies principally on discovering invariants that are inductive and adequate. Obtaining such invariants, therefore, has been studied widely from diverse perspectives, including even mining them from the input program’s source in a guess-and-check manner [13]. However, guessing candidates based on syntactical constructions of the source code has its limitations. For one, a required invariant may not manifest on the syntactic surface of the program. Secondly, a poor guess may give rise to a series of expensive checks. Furthermore, unlike conjunctions, refining disjunctive invariant candidates is unobvious and may frequently cause the proof search to diverge. This paper attempts to overcome these limitations, by learning from both – appearance and behaviours of a program. We present an algorithm that (i) infers useful invariants by observing a program’s syntactic source as well as its semantics, and (ii) looks for conditional invariants, in the form of implications, that are guided by counterexamples to inductiveness. Our experiments demonstrate its benefits on several benchmarks taken from SV-COMP and the literature.

Efficacy of oral rifampicin in chronic central serous chorioretinopathy

Objective: To evaluate the role of oral rifampicin in the management of chronic central serous chorioretinopathy. Methods: Retrospective analysis of patients diagnosed with chronic central serous chorioretinopathy (duration >3 months) and treated with oral rifampicin 600 mg daily for a maximum period of 3 months was carried out. Baseline visual acuity, fundus fluorescein angiography, and optical coherence tomography were recorded and the patients were followed up. Resolution of subretinal fluid and improvement in visual acuity were the main outcome measures. Recurrence of subretinal fluid was noted. Any adverse reaction to the drug was monitored. Results: Nine eyes of eight patients were included in the study. The average age of the patients was 41.90 years (range 32–52 years). Mean duration of symptoms was 16 months (range 3–60 months). Mean duration of follow-up was 10.11 months (range 3–33 months). Fluorescein angiography showed four eyes with subfoveal leaks and five eyes with diffuse retinal pigment epitheliopathy. Complete resolution of subretinal fluid was achieved in four of the nine eyes – two patients at the end of 1 month, one patient each at the end of 2 and 3 months, respectively. Visual acuity improvement was noted in four of the nine eyes. Three patients had one-line improvement and one patient had a two-line visual improvement. None of the patients had severe adverse events for which the drug had to be discontinued. None of the patients had recurrence of subretinal fluid after the discontinuation of the drug. Conclusion: Oral rifampicin could provide a useful, effective, and cost-effective alternative for treatment of patients with chronic central serous choroidopathy and evidence of healthier retinal pigment epithelium, those with focal leakage. It was not effective in eyes with diffuse retinal pigment epitheliopathy.

Scleral buckle infection by Serratia species

We describe a rare case of scleral buckle (SB) infection with Serratia species. A 48-year-old male with a history of retinal detachment repair with scleral buckling presented with redness, pain, and purulent discharge in the left eye for 4 days. Conjunctival erosion with exposure of the SB and scleral thinning was noted. The SB was removed and sent for culture. Blood and chocolate agar grew Gram-negative rod-shaped bacillus identified as Serratia marcescens. On the basis of the susceptibility test results, the patient was treated with oral and topical antibiotics. After 6 weeks of the treatment, his infection resolved.

Capillary Dropout: A Novel Fluorescein Angiography Finding in Primary Vitreoretinal Lymphoma

Tissue diagnosis with vitreous and/or retinal biopsy usually confirms the diagnosis of primary vitreoretinal lymphoma. Multiple imaging modalities like fundus fluorescein angiography, fundus autofluorescence, and optical coherence tomography have been used to support the diagnosis of vitreoretinal lymphoma. We report a case of a 74-year-old lady diagnosed with primary vitreoretinal lymphoma showing a novel fluorescein angiographic finding of capillary dropout. We hypothesize that this clinical finding on the fluorescein angiogram may be due to the occlusion of the retinal vasculature by the malignant tumor cells. This finding also suggests the possible intraocular invasion of the malignant lymphomatous cells into the inner retinal layers.

Appraising the spectrum of firework trauma and the related laws during Diwali in North India

Purpose: To evaluate the epidemiological characteristics and outcomes of ocular injuries resulting from the use of firecrackers during the Diwali festival in all age groups. Materials and Methods: A single-center, retrospective, hospital-based case series presenting with ocular trauma consequent to fireworks usage in a tertiary eye care center in North India during the 5 days of Diwali festival from 2011 to 2015 was conducted. Results: A total of 53 eyes of 45 patients were included in the study, out of which the vast majority (39/87%) were males. The mean age was 20.55 years. Almost an equal number of bystanders (25/55.5%) were affected as compared to people handling the fireworks (20/44.44%). Five (9.43%) eyes had open-globe injury, whereas 48 (90.56%) eyes had closed-globe injury. Eighteen (33.96%) eyes underwent surgical intervention. Thirty-three (62.26%) eyes had final vision >20/200 with eight (15.09%) eyes being vision <3/60 in the affected eye. Conclusion: Firework-related ocular trauma can lead to serious visual impairment. Mandatory legislative laws pertaining to the manufacture, sale, and use of fireworks and creating public awareness can reduce the incidence of this preventable cause of blindness in the society. Initiating new policies for retailers involved in sale of these firecrackers can also bring in decrease of such morbidities.