Disc Margin Research Articles

Malarial Retinopathy: Falci Not So Fan-See!

Malarial retinopathy is an established entity in cases of complicated falciparum malaria and cerebral malaria in children whereas, in adults it is rarely reported. Here we report a case of a 21-year-old male, with uncomplicated falciparum malaria, referred to the ophthalmology outpatient department with a chief complaint of sudden blurring of vision in both eyes. On examination, both eyes showed mild blurring of nasal optic disc margins with multiple intraretinal, preretinal haemorrhages, subhyaloid haemorrhage involving the macula and Roth spots, suggestive of malarial retinopathy. The patient was observed closely for spontaneous resolution and was treated systemically with anti-malarial drugs including injection artesunate and tablet doxycycline. On subsequent follow-up after 2 weeks, improvement in visual acuity with complete resolution of haemorrhages occurred. We aspire to bring to light a rare entity of malarial retinopathy and the need to not over-treat the condition.

Wide-Field Swept-Source OCT Analysis of Interocular Symmetry of Choroidal Thickness in Subjects with Uncomplicated Pachychoroid.

Background: We aimed to study the bilateral choroidal thickness (CT) symmetry and difference in uncomplicated pachychoroid subjects using wide-field swept-source optical coherence tomography (SS-OCT). Methods: All subjects underwent a wide-field 16-mm one-line scan using SS-OCT. Bilateral CT was measured at, and compared among, the following 12 points: three points at 900-µm intervals from the nasal optic disc margin (nasal peripapillary area), one point at the subfovea, six points at 900-µm intervals from the fovea to the nasal and temporal areas (macular area), and two peripheral points 5400 and 8100 µm from the fovea (peripheral area). Results: There were no statistically significant differences in CT between the right and left eyes in any area (all p > 0.05); they all showed significant positive correlations (all p < 0.01). However, the correlation coefficients (ρ) were smaller for the nasal peripapillary and peripheral areas compared to the macular area. Conclusions: The CTs in each region were bilaterally symmetrical in subjects with uncomplicated pachychoroid. However, interocular difference in CT increased from the center to the periphery, indicating that the anatomical variation of the nasal peripapillary and peripheral choroid was greater than that of the macula.

Risk factors for failure of resolving optic disc pit maculopathy after primary vitrectomy without laser photocoagulation.

To determine factors significantly correlated with the failure of macular reattachment by pars plana vitrectomy (PPV) without laser photocoagulation of the optic disc margin to treat optic disc pit (ODP) maculopathy. Retrospective, interventional case series. We reviewed the medical records of 35 consecutive patients with ODP maculopathy who underwent PPV without laser photocoagulation. PPV with the creation of a posterior vitreous detachment (PVD) was performed in 34 eyes. An epiretinal membrane and internal limiting membrane present in the other eye with a PVD were removed. Patients were followed for 12-193months (mean 58months) after surgery. The main outcome measures were the postoperative rate of retinal reattachment and best-corrected visual acuity. The preoperative clinical characteristics of the successful cases were compared to those of the unsuccessful cases. A complete retinal reattachment was attained in 31 of 35 eyes and it required about one year. The 4 other eyes that did not achieve a macular reattachment after the primary PPV underwent additional therapies. The factors that were significantly associated with a failure of a retinal reattachment after primary PPV were the presence of a retinal detachment connected to the optic disc (P < 0.001) and the presence of preoperative headaches (P = 0.030). Clinicians should be aware that the presence of a preoperative macular detachment connected to the optic disc margin and preoperative headaches are indicators for an unsuccessful outcome of PPV without laser photocoagulationin eyes with ODP maculopathy.

Bilateral Buried Optic Nerve Head Drusen Mimicking Idiopathic Intracranial Hypertension

Optic nerve head (ONH) drusen are buried deposits in the optic nerve head simulating papilloedema. Idiopathic Intracranial Hypertension (IIH) signifies raised intracranial pressure in the absence of intracranial space occupying lesion. A 35-year old woman diagnosed elsewhere with IIH and treated with oral acetazolamide for six months, presented with non-specific headache. Fundus showed bilateral blurring of disc margins, elevated disc and obscuration of cup. MRI of brain was normal. The non- resolution of disc edema despite six months of acetazolamide therapy raised suspicion of an alternate diagnosis. Ultrasound B-scan confirmed the diagnosis of ONH drusen. ONH drusen should be excluded before entertaining the diagnosis of IIH.

Dissipativity, inverse optimal control, and stability margins for nonlinear discrete-time stochastic feedback regulators

ABSTRACT In this paper, we derive stability margins for optimal and inverse optimal stochastic feedback regulators. Specifically, gain, sector, and disk margin guarantees are obtained for discrete-time nonlinear stochastic dynamical systems controlled by nonlinear optimal and inverse optimal controllers that minimise a nonlinear-nonquadratic performance criterion. Furthermore, using the newly developed notion of stochastic dissipativity we derive a return difference inequality to provide connections between stochastic dissipativity and optimality of nonlinear controllers for discrete-time stochastic dynamical systems. In particular, using extended Kalman-Yakubovich-Popov conditions characterising stochastic dissipativity we show that our optimal feedback control law satisfies a return difference inequality predicated on a difference operator of a controlled Markov dispersion process and is stochastically dissipative with respect to a specific quadratic supply rate.

Pediatric Giant Prolactinoma Presenting With Acute Obstructive Hydrocephalus and Intracranial Hypertension

Background: Pediatric prolactinomas (PP) are rare but represent 50% of all pediatric pituitary adenomas. Girls are affected more frequently than boys, although PP tend to be larger and more aggressive (earlier age, larger mass, and higher prolactin levels) in boys. Thus, microadenomas (tumors < 10 mm in diameter) are typical in females and macroadenomas (10–40 mm in diameter) are typical in males. Giant prolactinomas (> 40 mm in maximum diameter), an unusual subset of macroprolactinomas, are also commonly found in boys. In a large case series, the largest tumor volume reported was 93.5 cm3. Here we report a giant prolactinoma in a female requiring V/P shunt for decompression. Clinical Case: A 16-year old female presented with 2 weeks of intractable headache, nausea and vomiting, vision impairment, and changes in balance described as running into stationary household objects. Historical review revealed primary amenorrhea and short stature. On initial exam, the patient had a right eye afferent pupillary defect, concern for loss of color vision, and bilateral optic nerve edema with blurred disc margins. Brain MRI showed a large lobulated mass centered in the suprasellar cistern, measuring approximately 6.4 x 5.8 x 5.7 cm with a tumor volume of 105 cm3. There was extension superiorly, anteriorly, and laterally, with homogeneously enhancing and cystic components, and mass effect resulting in obstructive hydrocephalus. Differential diagnoses included craniopharyngioma, germinoma, and adenoma. Initial tests demonstrated prolactin of >2,000 ng/mL, with diluted result of 17,811.16 ng/mL. Morning fasting labs confirmed multiple anterior pituitary hormone deficiencies including central hypothyroidism, ACTH deficiency, GH deficiency, and hypogonadotropic hypogonadism. The patient was started on hydrocortisone and levothyroxine. Due to obstructive hydrocephalus and vision impairment, she underwent VP shunt placement for decompression. She was started on cabergoline for medical treatment of the tumor and did not require surgical resection. Repeat prolactin measurements have shown striking improvement (to 2,350 ng/ml, 824 ng/ml, and 152 ng/ml at 1 week, 1-month, and 2-month-follow-up, respectively) with central vision improved in both eyes, papilledema resolved, and resolution of headaches. Conclusion: Giant prolactinomas presenting with hydrocephalus and intracranial hypertension are very rare in pediatrics, especially in girls, and can vary greatly in mass characteristics and resulting hormone deficiencies. Our patient is unique with her large tumor volume and the extent of pituitary hormone deficiencies. Prolactin levels should be measured with all sellar masses, as this may prevent unnecessary invasive intervention and possibly provide prompt response to medical management.

A study on use of adjuvant therapy of steroid and antibiotics in treatment of unilateral retinitis following typhoid fever in a medical college in Kuppam

Purpose: To compare the efficacy of adjuvant therapy of topical steroids eye drops with oral antibiotics and monotherapy of oral antibiotics in a typhoid fever associated retinitis. Materials and Methods: The study was conducted on a 30yr old male who presented to our OPD with decreased vision in left eye and was followed up for 1 month. Results: A 30yr old male patient presented to our OPD with decreased vision with left eye with history of typhoid fever for a duration of 4 weeks and was treated successfully. His BCVA was 6/6 in Right Eye and 6/36 in Left Eye. Fundus examination revealed multiple whitish ill defined lesions suggestive of retinitis lesions which was noted superiorly to the disc which was associated with macular neuro-sensory detachment and blurring of disc margins in the left eye. Significant improvement in BCVA was observed with adjuvant therapy of topical steroids with antibiotics over a period of 1 month. Diagnosis of post typhoid immune mediated retinitis was made with good resolution following treatment. Keywords: Post typhoid retinitis, Immune mediated retinitis, Post fever retinitis.

Peripapillary hyperreflective ovoid mass-like structures (PHOMS) in children.

To analyse structural characteristics and perifoveal/peripapillary vasculature by OCT in children with peripapillary hyperreflective ovoid mass-like structures (PHOMS) and compare the results with those of normal subjects. Forty-five patients (84 eyes) under 18 years old with blurry disc margin were evaluated with spectral domain-OCT and swept course-OCT. Patients were divided into four groups, according to presence of PHOMS and then the size of the existing PHOMS. Eyes with visible optic disc drusen (ODD) were not included. Foveal avascular zone (FAZ) and vessel densities from macula and optic disc area were assessed and potential associations between vessel density and structural parameters, such as peripapillary retinal nerve fibre layer (pRNFL), and macular ganglion cell and inner plexiform layer (mGCIPL) thickness, were analysed. Among 45 patients (eighty-four eyes), coexisting buried ODD were found only in eyes with PHOMS. The scleral canal diameter was significantly smaller in PHOMS positive eyes compared to control eyes. Vessel density measurements from the papillary, peripapillary and optic nerve head (ONH) regions in the large PHOMS group were significantly lower compared to the control group (papillary; P = 0.014, peripapillary; P = 0.001, ONH; P = 0.046). FAZ area and macular vessel densities showed no difference compared to normal eyes in all three PHOMS groups. pRNFL and mGCIPL thickness did not differ among four groups and correlations were also not significant. Children with PHOMS have smaller scleral canal and can entail buried ODD. Vessel densities of optic disc area in large PHOMS eyes are significantly lower than in normal eyes.

Articular Disc of a Human Temporomandibular Joint: Evaluation through Light Microscopy, Immunofluorescence and Scanning Electron Microscopy.

The extracellular matrix of the articular disc in a temporomandibular joint (TMJ) is composed mainly of collagen I and elastin. The collagen is important for resisting tensile forces, while the elastin is responsible to maintain the shape after deformation. We studied the orientation of collagen and elastin in a normal human temporomandibular joint disc by light microscopy, immunofluorescence and scanning electron microscopy. Our results demonstrated that collagen and elastin run parallel to each other in the intermediate zone with an anteroposterior orientation. From here, the orientation of two fibers groups changes into a disordered arrangement in the transition zone. Numerous elastic fibers cross with the collagen fibers, defining an interwoven knitted arrangement. The evaluation of the disc–condyle relationship shows that the medial margin of the articular disc is inserted directly at the superficial layer of the mandibular condylar cartilage. Therefore, the tensile properties of the TMJ disc are expressed in the directions corresponding to the orientation of the collagen fibers, and the complex orientation of elastin with the collagen determines the maintaining of the shape after the stresses by the joint movements. Moreover, the direct anatomical relationship between the articular disc and the mandibular condyle makes a decisive contribution to the understanding of TMJ movements.

Factors Affecting Slip Reduction in Oblique Lumbar Interbody Fusion With Posterior Fixation for Degenerative Spondylolisthesis.

Study Design:Retrospective case seriesObjectives:Reduction of translational/angular slip is a favorable radiological result in spinal fusion for degenerative spondylolisthesis, although its clinical significance remains controversial. Few studies have investigated slip reduction and associated factors in oblique lumbar interbody fusion (OLIF) for degenerative spondylolisthesis.Methods:This study involved a retrospective analysis of 56 operated levels of 52 consecutive patients who underwent OLIF for degenerative spondylolisthesis and had more than 1-year of regular follow-up. Translational/angular slip, anterior/posterior disc height, and spinopelvic parameters were measured preoperatively, postoperatively at 6-weeks, and at the last follow-up. Demographic, radiological, and surgical parameters were analyzed to determine factors associated with the amount of slip reduction.Result:The mean follow-up duration was 30.4 ± 12.9 months (range, 12 to 61). The mean decrease in translational slip was 5.7 ± 2.1 mm (13.6 ± 5.5%) and the mean increase in angular slip was 7.9 ± 7.1° at the last follow-up (both P < 0.001). The amount of slip reduction was greater in female sex, age < 65 years, use of a 12° cage, cage position from the anterior disc margin of < 7 mm, and cases with posterior decompression (laminectomy with inferior facetectomy).Conclusions:OLIF showed satisfactory translational/angular slip reduction in degenerative spondylolisthesis. Surgical techniques for optimal reduction include the use of a large angle cage, anterior cage placement, and resection of the inferior facet.

A comparison of optic disc area measured by confocal scanning laser tomography versus Bruch\u2019s membrane opening area measured using optical coherence tomography

BackgroundPrecise optic disc size measurements based on anatomically exact disc margins are fundamental for a correct assessment of glaucoma suspects. Computerized imaging techniques, such as confocal-scanning-laser-tomography (CSLT), which applies operator defined boundaries and optical-coherence-tomography (OCT), which incorporates an alternative detectable landmark (Bruch’s-membrane-opening (BMO)), have simplified the planimetry of the optic disc and BMO-area, respectively. This study’s objectives are to compare both modalities for area and to define a threshold for macro-BMO using BMO-OCT.MethodsRetrospectively, patients that simultaneously received CSLT and BMO-OCT scans were included. Their images were correlated and agreement was determined using Bland-Altman-analysis. The diagnostic power of a macro-BMO threshold using OCT was derived after creating a receiver-operating-characteristics-curve using the well-established analogous CSLT threshold (2.43 mm2).ResultsOur study included 373 eyes with a median optic disc area by CSLT/ BMO-area by OCT of 2.56 mm2 and 2.19 mm2 respectively. The Bland-Altman-analysis revealed a systematic deviation with a diverging tendency with increasing area, which enabled the creation of the following mathematical relation: disc-area (CSLT)*0.73 + 0.3 = BMO-area (OCT). BMO-area of 2.19 mm2 showed the best diagnostic power for identifying macro-BMOs using OCT (sensitivity: 75%, specificity: 86%).ConclusionsArea measurements (CSLT optic disc area vs. BMO-area by OCT) showed a systematic deviation with a divergent tendency with increasing size. Our mathematical equation offers an estimated comparison of these anatomically diverse entities. Considering BMO-OCT´ anatomical accuracy, the 2.19 mm2 threshold may improve discernment between glaucoma suspects and norm variants.

Adaptive Cruise Control With Gain Scheduling Technique Under Varying Vehicle Mass

Today, advanced driver-assistance systems (ADAS) come up with different abilities. One of them is the adaptive cruise control (ACC) system. The ACC system is a continuation of research on cruise control (CC) system, which integrates spacing control with the existing velocity control on the CC system. The vehicles with an ACC system guarantee traffic safety while at the same time ensure a well-driving sense. Many studies have demonstrated numerous control techniques applied as ACC controllers to accomplish uncertainty and perturbation issues. Nevertheless, most of the existing papers assumed the model vehicle dynamics as a linear time-invariant (LTI) system while designing the ACC controller. This paper proposed an ACC controller using the gain scheduling technique to deal with the model vehicle dynamics as a linear parameter varying (LPV) system. The passenger vehicle’s mass varies during ACC operation depending on how many passengers or loads on the vehicle’s trunks. Later, the vehicle’s mass is estimated by recursive least square (RLS) with a forgetting factor. Then, the disk margin is utilized to provide the high-level robustness at each operating or “frozen” point. The robustness performance will be analyzed using the worst-case gain metric while the uncertainty is modeled by integral quadratic constraints (IQC). The LPV system behavior, such as the rate vehicle’s mass, is also considered in the analysis. The effectiveness algorithm is validated through joint simulation between Matlab/Simulink and PreScan. The last, the comparison performance between gain scheduling and fixed gain ACC controller is evaluated.

Diclofenac-induced papilledema

A 32-year-old female came to the outpatient with complaints of headache. She was taking tablet diclofenac over the counter for the same without proper prescription from the doctor. On examination, anterior segment appeared normal with vision in both eyes 6/9 partial not improving with pinhole. Intraocular pressures were 14 mmHg and 13 mmHg in the right and left eye, respectively. Fundus examination by 90 D slit-lamp biomicroscopy showed blurring of disc margins. On fundus photograph examination, it revealed that the disc margins of both eyes were blurred, indicating grade four papilledema (Frisen papilledema grading system). The patient was administered anti edema measures for her condition and after a month; there were symptomatic improvement with the fundus photography confirming the resolution of papilledema. The patient was advised against nonsteriodial anti-inflammatory drugs in the future as there is a likely chance of the same idiosyncratic reaction, after a thorough systemic work-up was done to rule our other causes of the same.

Optic Disc Drusen &amp; a Constellation of Other Features of Retinitis Pigmentosa: A Case Report

<i>Aim: </i>We describe a case of optic disc drusen in retinitis pigmentosa with a myriad of other ocular associations of retinitis pigmentosa coexisting in our patient. To the best of our knowledge, this is the first case reported in a Nigerian. <i>Method: </i>This is a case report of a 16 year old who presented top our eye clinic with a 2 year history of poor night vision with an associated history of difficulty seeing far since childhood. The best corrected visual acuity was 6/18 and 6/12 respectively in the right and left eye. Slit lamp biomicroscopy revealed bilateral grade 1 posterior subcapsular cataracts. Binocular indirect ophthalmoscopy of both eyes revealed vitreous opacities, pale, cupped discs with nasalization of the vessels and yellowish, crystalline deposits at the inferior and superior disc margins. The retina was pale with attenuated vessels, bone spicule pigmentation, atrophic maculopathy and epiretinal membranes bilaterally. <i>Results:</i> An assessment of optic disc drusen, glaucoma, atrophic maculopathy with epiretinal membrane in retinitis pigmentosa was made. The diagnosis of optic disc drusen was confirmed by characteristic ocular B-scan findings. He was commenced on guttae betaxolol BD in both eyes and counselled on the nature of the eye pathology. <i>Conclusion: </i>Optic disc drusen co-exists with retinitis pigmentosa. Though uncommon, optic disc drusen may occur in Africans as seen in our patient. Other ocular associations including myopia, glaucoma and macula lesions like epiretinal membrane and atrophic maculopathy may also be present. The central visual field changes in a patient with retinitis pigmentosa, optic disc drusen and glaucoma may be attributable to all three ocular entities and not just the glaucoma. Prompt diagnosis, follow –up and adequate patient counselling is essential in the management of these patients.

Anti-GFAP neuroinflammation with synchronous bilateral papillitis and characteristic imaging

A 50-year-old female marine ecologist presented to the emergency department following 3 weeks of persistent headache, nausea, vomiting, disturbed vision, intermittent aural pulsations, unsteady gait and acroparesthesias. She had previously...

Ultrastructure of the egg of Coquillettidia venezuelensis (Theobald)(Diptera: Culicidae).

This study examined the ultrastructural characteristics of the egg of Coquillettidia venezuelensis (Theobald) (Diptera: Culicidae) with the aid of scanning electron microscopy. The eggs are elliptical and blackish, measuring on average 525.3 ± 12.8 μm in length and 94.9 ± 5.14 μm in width, with a length to width ratio of 5.54 ± 0.18. The anterior region of the egg is tubuliform, with a well-developed micropylar collar measuring approximately 2.54 ± 0.33 μm in thickness, the inner side of which is uniformly and deeply excavated, with a depression around the outer margin of the micropylar disc, which has a diameter of 29.4 ± 1.7 μm, an area of 234.4 μm2 ± 401.3 μm2 and a slightly elevated central region measuring 1.7 ± 0.5 μm in diameter that bears the central micropyle.

Pseudotumor cerebri in patient on leuprolide acetate for central precocious puberty

BackgroundGonadotropin releasing hormone agonists (GnRHa) are well established as a standard of care for the treatment of central precocious puberty (CPP) worldwide. While numerous delivery systems and routes of administration exist, depot intramuscular injections or sustained-release preparations have been most widely used. Leuprolide acetate is well tolerated among children though some can develop some complications.Case presentationWe present a case report of a 6.5 year old girl with central precocious puberty who developed signs of pseudotumor cerebri after 2 doses of leuprolide acetate 3.75 mg given monthly. Systemic exam and other tests to look for the cause did not yield anything. However, fundoscopy showed marked papilloedema with blurred disc margins. After six weeks’ treatment with acetazolamide and withdrawal of the GRNHa the papilloedema resolved.ConclusionsIf a patient presents with complaints such as headache, nausea, vomiting, and double vision in pediatric patients treated with GnRH analogue one should highly consider the presence of pseudotumor cerebri and fundus examination be performed.

Is a virtual clinic model a safe and effective way for assessing patients referred with suspiciously blurred optic discs? The blurred disc clinic.

There are increasing numbers of referrals to ophthalmology departments due to blurred optic disc margins. In light of this and the COVID-19 pandemic we aimed to assess whether these patients could be safely assessed without direct contact between the clinician and patient. We retrospectively reviewed the records of consecutive patients seen in our 'blurred disc clinic' between August 2018 and October 2019. We then presented anonymous information from their referral letter, their visual fields and optic nerve images to two consultant neuro-ophthalmologists blinded to the outcome of the face-to-face consultation. In the simulated virtual clinic, the two consultants were asked to choose an outcome for each patient from discharge, investigate or bring in for a face-to-face assessment. Out of 133 patients seen in the blurred disc clinic, six (4.5%) were found to have papilloedema. All six were identified by both neuro-ophthalmologists as needing a face-to-face clinic consultation from the simulated virtual clinic. One hundred and twenty (90%) patients were discharged from the face-to-face clinic at the first consultation. The two neuro-ophthalmologists chose to discharge 114 (95%) and 99 (83%) of these respectively from the simulated virtual clinic. The virtual clinic would have potentially missed serious pathology in only one patient who had normal optic discs but reported diplopia at the previous face-to-face consultation. A virtual clinic model is an effective way of screening for papilloedema in patients referred to the eye clinic with suspicious optic discs. Unrelated or incidental pathology may be missed in a virtual clinic.

Multiple cranial nerve enlargement in Charcot-Marie-Tooth disease

Hypertrophy of peripheral nerves are commonly reported in patients with demyelinating forms of Charcot-Marie-Tooth disease (CMT).1 Herein, an under-recognised association with hypertrophy of multiple cranial nerves in a patient with...

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Lecanographa atlantica&lt;/em&gt; (Arthoniales, Lecanographaceae), a widespread and conspicuous but still undescribed lichen-forming fungus&lt;/strong&gt;&lt;/p&gt;

Lecanographa farinosa was considered to be a lichen inhabiting coastal rocks of the Mediterranean region and to possess psoromic and conpsoromic acids as major secondary metabolites. A revision of its type specimen from Germany proved that the species has been misunderstood. In this paper, L. farinosa is shown to have a thallus containing confluentic and 2’-O-methylmicrophyllinic acids and to have a different ecology and distribution. A revision of previous reports of L. farinosa from continental Portugal and the study of recent specimens of Lecanographa cf. farinosa from the Azores, Canary Islands, Cape Verde and continental Portugal revealed a new species described as L. atlantica. Moreover, reports of L. dialeuca from France (Brittany) and of L. subgrumulosa from the Azores are considered misidentifications of L. atlantica. This latter has thus a widespread distribution ranging from the Azores to the Atlantic coast of the European continent where it inhabits volcanic rocks near the sea. Lecanographa atlantica is characterized by a whitish to cream coloured thallus, usually rounded or oblong to shortly lirelliform and white pruinose ascomata with a widely exposed hymenial disc and thin margin, (3–)5–7-septate ascospores of (16–)18.9–23(–26) × (3–)3.4–4(–4.5) µm, and a chemistry including at least 2’-O-methylperlatolic acid but lacking confluentic and 2’-O-methylmicrophyllinic acids. Psoromic acid is sometimes present in L. atlantica but its origin is unclear. Phylogenetic analyses using nuLSU sequences place L. atlantica as sister to L. hypothallina.