Evaluation of stress distribution in and around dental implants using three different implant-abutment interfaces with platform-switched and non-platform-switched abutments: A three-dimensional finite element analysis.

Background: A key factor for the success or failure of an implant is how the stresses are transferred to the surrounding bone. The implant‒abutment connection (IAC) is paramount for implant success. The purpose of this finite element analysis (FEA) study was to evaluate the stress distribution in and around three different implant‒abutment interfaces with platform-switched and platform-matched abutments using the finite element method (FEM). Methods: Three distinct types of IAC were selected: tri-channel internal connection, conical connection, and internal hex connection. Six models were generated, three in platform-switched and three in non-platform-switched configuration. Computer-Aided Three-Dimensional Interactive Application (CATIA) V5 R20 software was used to generate virtual models of the implants and the mandible. The models were transferred to Analysis of Systems (ANSYS) 15.0 software, in which the models were meshed and underwent FEA. Results: On the crestal bone, the highest von Mises stresses in platform-switched abutments were noticed in the internal hex implant‒abutment system (370 MPa), followed by the tri-channel implant‒abutment system (190 MPa) and conical implant‒abutment system (110 MPa). On the implant and the abutment screw, the highest von Mises stresses were observed in the internal hex implant‒abutment system, followed by the conical implant abutment system and tri-channel implant‒abutment system. Platform-switched implants had a more favorable stress distribution on crestal bone. Conclusion: Within the constraints of the current study, the internal hex connection exhibited the highest stress. In contrast, the conical abutment connection with platform switching configuration had more favorable stress distribution in crestal bone than other implant abutment systems.

ROP examination of premature babies at an eye hospital referred from urban and semi-urban NICUs.

INTRODUCTION: Retinopathy of prematurity (ROP) is seen in low gestational age (GA) and birth weight (BW) babies leading to retinal vascular damage. Screening of preterm would help in early identification of this, sight-threatening disease. Multiple factors play an important role in planning screening strategies for these preterm. The objective of this study was done to find the differences and the reasons affecting the proportion of ROP distribution between urban and semi-urban regions in North India. MATERIALS AND METHODS: In this retrospective, comparative study, all babies referred for ROP examination by paediatricians or other general ophthalmologists between 2013 to 2016 were included in the study. Demographic, clinical and treatment related findings were recorded. RESULTS: Five hundred and fifty eight babies (467: urban and 91: semi urban) were examined for ROP. The mean BW in urban and semi-urban settings was 1348.6 ± 395.21 gm and 1703.77 ± 401.76 gm respectively. The mean GA was 30.99 ± 2.93 weeks and 30.73 ± 2.08 weeks in the urban and semi-urban cohorts respectively. The average time for first ophthalmic examination following birth was 23.82 ± 13.69 (range: 3-77) days in urban and 101.16 ± 238.26 (range: 13- 330) days in semi-urban settings. 94% of the babies completed all screening examination visits. Any ROP was identified in 12% and 33.0% of urban and semi-urban cohorts respectively; Type 1 was detected in 7.5% of urban babies and 24% of semi-urban babies. CONCLUSION: Proportion of ROP in the urban region was 3 times lesser than the semiurban region. Differences in proportion of babies developing any ROP and Type 1 ROP between semi-urban and urban groups is likely due to selection bias, as a high proportion of semi-urban babies did not attend for examination or failed to complete all the examinations necessary. This was particularly true for females. More needs to be done to increase access to regular, systematic screening of preterm babies within neonatal units.

ARTEFACTUALLY DAMPENED FLASH STIMULUS VISUAL EVOKED RESPONSES IN A SILICONE OIL-FILLED EYE.

PURPOSE: To report a case of falsely dampened visual evoked responses in a patient of Usher syndrome after retinal detachment surgery secondary to probable intraocular silicone oil. METHODS: Retrospective observational case report. CASE DESCRIPTION: A 16-year-old boy with Usher syndrome developed rhegmatogenous retinal detachment in the left eye. He underwent a successful retinal detachment surgery with silicone oil tamponade. On his postoperative follow-up visit, poor vision was noted by our optometrist. A flash stimulus visual evoked response was done, which showed marked delayed latency and reduced amplitude. Marked improvement in the flash stimulus visual evoked response potentials and waveforms was noted after silicone oil removal. CONCLUSION: Intraocular silicone oil could be responsible for this false delay in the latency and reduction in flash stimulus visual evoked response amplitudes. Assessment of flash stimulus visual evoked responses in the presence of silicone oil after vitreoretinal surgery may produce unreliable responses.

Post-traumatic endophthalmitis in children.

PURPOSE: To study the clinico-microbiological profile and evaluate the functional and anatomical outcomes of pediatric post-traumatic endophthalmitis (PPTE). METHODS: This was a retrospective interventional case series. All medical case records of patients diagnosed with PPTE over a 5-year period from January 2011 to December2015 were reviewed. Data recorded was: age, sex, type of trauma, mode of injury, interval between trauma and presentation, treatment, follow-up duration and final functional and anatomical outcomes. RESULTS: Forty-one eyes of 41 patients diagnosed with PPTE met the inclusion criteria. There were 26 boys and 15 girls. The mean age at the time of presentation was 7.34 years (1month -16years). The median interval between trauma and presentation was 3 days (mean = 13.71 days; 1-240 days). The average follow-up period was 292.24 days (median 150 days; 30 1440 days). Injury with wooden stick (20,50%) was the most common mode of injury. Culture positivity was noted in 25(61%) cases. Staphylococcusaureus was the most common organisms identified on culture. Univariate analysis of in dependent variables was done using the Chi-square test showed patients with positive culture for gram-positive organisms had better anatomical (p=0.038) and functional outcomes (p=0.043). 35(85%) patients underwent vitrectomy along with intraocular antibiotics. Optimal anatomical and functional outcomes were noted in 23(56.1%) and12(29.3%) respectively. CONCLUSION: PPTE carries a significantly poor prognosis in terms of ocular integrity and visual function. PPTE is common in boys and often caused by vegetative matter. Staphylococcus aureus is the most common organism seen in PPTE. Early presentation following trauma and identification of gram-positive organisms have a better prognosis.

Optic nerve head retinal artery macroaneurysm: Report of a case.

A 61-year-old elderly male, hypertensive patient presented to the retina clinic with sudden drop in vision in the left eye for 6 days. His best-corrected visual acuity at presentation was counting fingers close to face. Fundus examination of the left eye revealed the presence of subretinal and preretinal haemorrhage at the macula along with hypertensive retinopathy changes in both eyes. Fluorescein angiography was done, which showed a retinal artery macroaneurysm at the optic nerve head. Optical coherence tomogram through the optic nerve head also confirmed the presence of retinal artery macroaneurysm. The patient was treated with injection of 0.4 cc of 100% C3F8 to displace the blood off the macula. At final follow-up visit at 2 months post treatment, his vision improved to 6/12, N8. Fundus examination showed a small residual altered blood nasal to the fovea. No treatment was however done to the retinal artery macroaneurysm due to its atypical location and chance of spontaneous involution. In conclusion, retinal artery macroaneurysm at the optic disc is extremely uncommon. Identification of the retinal artery macroaneurysm lesion is more difficult in glaucoma patients due to the large and deep optic cup. Fluorescein angiography remains the main investigative modality to confirm the diagnosis. Spontaneous involution still remains the mainstay of treatment in optic disc retinal artery macroaneurysm.

IATROGENIC CHOROIDAL NEOVASCULAR MEMBRANE IN MACULAR HOLE-INDUCED RETINAL DETACHMENT.

PURPOSE: To report a case of choroidal neovascular membrane after vitreoretinal surgery in a patient with macular hole-induced retinal detachment. METHODS: Retrospective observational case report. CASE DESCRIPTION: A 64-year-old lady presented with sudden drop in vision in the right eye since 20 days. Her best-corrected visual acuity was 6/36 in the right eye and 6/18 in the left eye. She was diagnosed with retinal detachment with a macular hole in the right eye. She underwent vitrectomy with internal limiting membrane peeling and gas tamponade for the retinal detachment. Internal limiting membrane peeling was performed after staining with brilliant blue green dye and over the detached retina. Drainage of the subretinal fluid was performed through the macular hole and drainage retinotomy. Four months of postoperative examination revealed a scarred subfoveal choroidal neovascular membrane and retinal pigment epithelial atrophy surrounding it. This was confirmed by fluorescein angiography and optical coherence tomography. CONCLUSION: Visual loss secondary to choroidal neovascular membrane can occur because of surgical trauma to the retinal pigment epithelium and Bruch membrane. Drainage of the subretinal fluid should be preferably avoided through the macular hole to prevent this complication.

Retinal meteor.

We describe a case of a 65-year old man diagnosed with retinal vasoproliferative tumour secondary to posterior uveitis. The fluorescein angiography shows an interesting meteor-like leak emanating from the tumour and rising towards the superior retina in the later frames of the angiogram. Pictorially, we call it the "Retinal Meteor" and also describe the possible mechanism for this pattern of leakage.

Clomiphene citrate-induced visual hallucinations: a case report.

BACKGROUND: Polycystic 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 PRESENTATION: A 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. CONCLUSIONS: Clomiphene 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.

Ocular infection with Gliocladium species-report of a case.

PURPOSE: The purpose of this study is to report a case of ocular infection with Gliocladium species due to an exposed scleral buckle. DESIGN: Interventional case report was used as the study design. METHODS: A 60-year-old diabetic male patient presented with persistent pain, redness, and discharge in his left eye since 2 months. He had been treated previously with both topical and systemic steroids for a diagnosis of autoimmune scleritis. He had undergone scleral buckling surgery with cryotherapy for an inferior rhegmatogenous retinal detachment in the past. His best-corrected visual acuity was 6/6, N6 and 6/6, N6 in the right and left eyes, respectively. Retraction of the left lower lid revealed an exposed scleral buckle with an overlying necrotic conjunctiva. Scleral buckle removal was done. Microbiological examination showed Gliocladium species growing on blood agar and Sabouraud dextrose agar. Treatment was started with topical antifungal medication and oral antibiotics. RESULTS: Following treatment, signs of infection showed resolution. Patient underwent retinal reattachment surgery with favorable anatomic and visual outcome. CONCLUSION: Ocular infection with Gliocladium species has not been previously reported. Poor response to steroids and uncontrolled diabetes should make the clinician aware of a possible fungal infection. Removal of the scleral buckle, identification of the causative organism, and use of appropriate antibiotics are important for the accurate management of the case.

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.

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.