Technique for the Management of Extensive Ocular Surface Lipodermoid Involving the Cornea of Children.

PURPOSE: Ocular surface lipodermoids with corneal involvement may require surgical intervention; if deep, ocular surface reconstruction with lamellar corneal tissue or amniotic membrane may be needed. We describe a staged technique using autologous ipsilateral simple limbal epithelial transplantation. METHODS: After verifying sparing of Descemet membrane, the conjunctival portion of the lipodermoid was debulked in the first stage. Six weeks later, the corneal portion was excised, followed by autologous ipsilateral simple limbal epithelial transplantation to promote rapid reepithelialization of the residual stromal bed. Temporary tarsorrhaphy was used for patient comfort and to expedite ocular surface healing. RESULTS: Three eyes of 3 children with grade III large ocular surface lipodermoids that encroached the visual axis and hindered proper eyelid closure underwent surgery without complications. In all cases, the visual axis was cleared and eyelid closure was improved. At the last follow-up (mean 35.7 months, median 36.0 months), the bed of the original dermoid showed minimal haze in 1 case, while 2 eyes developed small pseudopterygium; best spectacle-corrected visual acuity improved from 20/200 to 20/70 in the first case, from fix and follow to 20/50 in the second case, and remained fix and follow in the last case, but this child had congenital hydrocephalus with severe developmental delay. CONCLUSIONS: This surgical technique is a promising option for children with grade III large ocular surface lipodermoids given its effectiveness in clearing the visual axis and in improving eyelid closure. Moreover, it does not require lamellar corneal transplantation or intervention to the fellow eye.

Bilateral Acute Angle-Closure Glaucoma: A Case Report of an Unusual Cause of Acute Headache in a Child.

INTRODUCTION: Acute angle-closure glaucoma (AACG) is typically considered a disease of adulthood. However, AACG may occasionally be seen in children. The clinical presentation is similar to adults, including headache, vomiting, and eye pain. However, the etiology of angle closure in children is different and most often associated with congenital anterior segment abnormalities. A precipitating factor of AACG in children with previous established, anterior segment abnormalities is eye dilation, which may occur during routine ophthalmological examination with topical mydriasis, or physiologic mydriasis upon entering a dark room. CASE REPORT: We describe a 5-year-old child with a history of severe prematurity and retinopathy of prematurity (ROP) presenting with bilateral AACG following a routine outpatient, dilated ophthalmological examination. While angle-closure glaucoma has previously been reported in cases of ROP, a bilateral acute attack of AACG following pupil dilation in regressed ROP has hitherto been unreported. CONCLUSION: Given the association of ROP and AACG, it can be expected that as the survival rate of premature infants improves, the incidence of ROP and AACG may also increase. It is therefore prudent for the emergency physician to have AACG on the differential for pediatric patients with headache and eye pain.

Human Meibum Age, Lipid-Lipid Interactions and Lipid Saturation in Meibum from Infants.

Tear stability decreases with increasing age and the same signs of instability are exacerbated with dry eye. Meibum lipid compositional changes with age provide insights into the biomolecules responsible for tear film instability. Meibum was collected from 69 normal donors ranging in age from 0.6 to 68 years of age. Infrared spectroscopy was used to measure meibum lipid phase transition parameters. Nuclear magnetic resonance spectroscopy was used to measure lipid saturation. Increasing human meibum lipid hydrocarbon chain unsaturation with age was related to a decrease in hydrocarbon chain order, cooperativity, and in the phase transition temperature. The change in these parameters was most dramatic between 1 and 20 years of age. Meibum was catalytically saturated to determine the effect of saturation on meibum lipid phase transition parameters. Hydrocarbon chain saturation was directly related to lipid order, phase transition temperature, cooperativity, changes in enthalpy and entropy, and could account for the changes in the lipid phase transition parameters observed with age. Unsaturation could contribute to decreased tear film stability with age.

Evaporation and Hydrocarbon Chain Conformation of Surface Lipid Films.

PURPOSE: The inhibition of the rate of evaporation (Revap) by surface lipids is relevant to reservoirs and dry eye. Our aim was to test the idea that lipid surface films inhibit Revap. METHODS: Revap were determined gravimetrically. Hydrocarbon chain conformation and structure were measured using a Raman microscope. Six 1-hydroxyl hydrocarbons (11-24 carbons in length) and human meibum were studied. Reflex tears were obtained from a 62-year-old male. RESULTS: The Raman scattering intensity of the lipid film deviated by about 7 % for hydroxyl lipids and varied by 21 % for meibum films across the entire film at a resolution of 5 µm2. All of the surface lipids were ordered. Revap of the shorter chain hydroxyl lipids were slightly (7%) but significantly lower compared with the longer chain hydroxyl lipids. Revap of both groups was essentially similar to that of buffer. A hydroxyl lipid film did not influence Revap over an estimated average thickness range of 0.69 to >6.9 µm. Revap of human tears and buffer with and without human meibum (34.4 µm thick) was not significantly different. Revap of human tears was not significantly different from buffer. CONCLUSIONS: Human meibum and hydroxyl lipids, regardless of their fluidity, chain length, or thickness did not inhibit Revap of buffer or tears even though they completely covered the surface. It is unlikely that hydroxyl lipids can be used to inhibit Revap of reservoirs. Our data do not support the widely accepted (yet unconfirmed) idea that the tear film lipid layer inhibits Revap of tears.

Pilot study of the influence of eyeliner cosmetics on the molecular structure of human meibum.

BACKGROUND/AIMS: It has been suggested that eye makeup could interact with human meibum causing a decrease in the stability of the tear film. The aim of this pilot study was to measure makeup-human meibum interactions in vitro. METHODS: Human meibum-makeup interactions were quantified by measuring order-to-disorder lipid phase transitions using infrared spectroscopy. RESULTS: Makeup products exhibited lipid phase transition temperatures that were much higher than those for meibum. One product increased the lipid phase transition temperature by 4.2°C when combined with human meibum causing a large increase (from 30 to 49%) in the order of the meibum-lipid hydrocarbon chains and significantly decreased the minimum frequency, enthalpy and entropy of the phase transition of human meibum. Another eyeliner caused no significant (p < 0.05) change in the phase transition parameters of human meibum. CONCLUSION: Infrared spectroscopy may be used to measure interactions between human meibum and makeup. One makeup product increased the lipid order (viscosity) which could have adverse effects on tear film stability. Modern cosmetics are highly regulated and relatively safe to use; however, it could be beneficial to design makeup products that do not interact with meibum, especially since women have a higher prevalence of dry eye symptoms.

Dental Procedures, Oral Practices, and Associated Anxiety: A Study on Late-teenagers.

OBJECTIVES: The study aims to determine the degree of anxiety pertaining to dental procedures and various oral hygiene practices among college teenagers. METHODS: Corah's Modified Dental Anxiety Scale was administered on a randomly chosen sample of 100 Indian college students (50 males and 50 females) of Delhi University, belonging to the age group of 17-20 years. RESULTS: Descriptive statistical computations revealed 12.14 years as the mean age of first dental visit, with moderately high levels of anxiety (60.75%) for various dental procedures among the Indian teenagers and 5% lying in the "phobic or extremely anxious" category. With merely 4.16% people going for regular consultations, general check-ups evoked 78.3% anxiety and having an injection or a tooth removed was perceived as the most threatening. The sample subgroup not using mouthwash and mouthspray, smokers, and alcohol drinkers with improper oral hygiene practices experienced much higher anxiety towards routine dental procedures. CONCLUSION: The majority of the Indian youngsters had an evasive attitude of delaying dental treatment. The core problems lay in deficient health care knowledge, lack of patient-sensitive pedagogy to train dental professionals, inaccessibility of services, and a dismissive attitude towards medical help. The feelings of fear and anxiety prevalent among the Indian youth offer significant insights into causes and preventive measures for future research and practice. Methods of education and motivation could be developed to dissipate the anxiety amongst Indian teenagers that prevent routine dental visits and maintenance of adequate oral hygiene.

Ketamine and intraocular pressure in children.

STUDY OBJECTIVE: We determine the increase in intraocular pressure during pediatric procedural sedation with ketamine, and the proportion of children whose increase might be clinically important (at least 5 mm Hg). METHODS: We prospectively enrolled children aged 8 to 18 years, chosen to receive ketamine sedation in a pediatric emergency department. We measured intraocular pressure before sedation, immediately after ketamine administration, 2 minutes post-drug administration, and every 5 minutes thereafter until recovery or 30 minutes after the final dose. We descriptively report our observations. RESULTS: For the 60 children enrolled, the median intraocular pressure increase was 3 mm Hg (range 0 to 8 mm Hg). Fifteen children had a brief greater than or equal to 5 mm Hg increase in intraocular pressure from baseline. CONCLUSION: In this study of ketamine sedation in children with healthy eyes, we observed mild increases in intraocular pressure that at times transiently exceeded our bounds for potential clinical importance (5 mm Hg).

Confirmation of the presence of squalene in human eyelid lipid by heteronuclear single quantum correlation spectroscopy.

(1)H-NMR spectroscopy has been used to quantify squalene in meibum and sebum. Squalene has many beneficial properties and its loss on the surface of skin upon ultraviolet light exposure or in the tear film with dry eye could be detrimental. In this study, we confirm the NMR proton resonance assignments of squalene, squalene in human meibum, and in human eyelid lipid using heteronuclear single quantum correlation spectroscopy. Our results confirm the presence of squalene in eyelid lipid. We speculate that the squalene in eyelid lipid could be secreted from sebaceous glands. The NMR resonances between 5.2 and 5.0 ppm, characteristic of the =CH of squalene, were resolved in the spectrum of human meibum and used to estimate that 1 % or less of squalene is present in meibum. However, the resonance assignments of squalene in meibum were not confirmed. The characteristics of squalene including its anti-inflammatory, antioxidant, and antibacterial qualities suggest that the presence of a squalene film is beneficial. Its loss in human meibum from patients with dry eye could be detrimental and contribute to the symptoms observed in these patients.

Lipid order, saturation and surface property relationships: a study of human meibum saturation.

Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum suggests greater film stability especially under the high shear stress of a blink.

13C and 1H NMR ester region resonance assignments and the composition of human infant and child meibum.

Recent NMR studies suggest that unsaturation may contribute to tear film instability in adults and loss of cholesteryl esters and squalene could reduce tear film stability in adults with meibomian gland dysfunction. The proton resonances were tentatively assigned in those studies. In this current investigation, meibum from seven infants and children, one adult and a pool of adult meibum have been analyzed using an NMR spectrometer with greater sensitivity and spectral resolution. The goals of this work are to confirm/correct the previous assignments and to determine possible age-related changes in composition. The initial resonance assignments were confirmed using heteronuclear single quantum correlation spectroscopy. Because there were no significant interferences in the spectral region corresponding to the resonances for cholesteryl and wax esters, the areas of these resonances were used to calculate their molar ratios. We calculated a wax ester:cholesteryl ester molar ratio of 1:0.57 ± 0.05 for all our meibum samples and there were no age-related differences. At lower film thicknesses, the rate of evaporation measured in vitro was lower for wax esters mixed with a long chain cholesteryl ester compared to wax esters alone. However, the film thicknesses tested were non-physiological. Longer chain cholesteryl esters increase the interactions between hydrocarbon chains. Hydrocarbon chains were more saturated in meibum from infants and children compared to adults. Unsaturation may contribute to tear film instability in adults. Loss of cholesteryl ester and squalene could destabilize tear film in adults with meibomian gland dysfunction.

Functionalization of titanium based metallic biomaterials for implant applications.

Surface immobilization with active functional molecules (AFMs) on a nano-scale is a main field in the current biomaterial research. The functionalization of a vast number of substances and molecules, ranging from inorganic calcium phosphates, peptides and proteins, has been investigated throughout recent decades. However, in vitro and in vivo results are heterogeneous. This may be attributed partially to the limits of the applied immobilization methods. Therefore, this paper highlights the advantages and limitations of the currently applied methods for the biological nano-functionalization of titanium-based biomaterial surfaces. The second part describes a newer immobilization system, using the nanomechanical fixation of at least partially single-stranded nucleic acids (NAs) into an anodic titanium oxide layer as an immobilization principle and their hybridization ability for the functionalization of the surface with active functional molecules conjugated to the respective complementary NA strands.

Cellular response of titanium and its alloys as implants.

The cellular response of osteocytes to commercially pure titanium (α) and its alloys (α + ß and ß) has been tested in a culture media, and the results have been supplemented by analyses from various techniques such as inductively coupled plasma atomic emission spectroscopic (ICP-AES) analysis, X-ray photoemission spectroscopy (XPS), scanning electron microscopy (SEM), metallography, and electrochemical measurements. These results have been correlated with respect to the presence of various alloying elements in these alloys to qualify them for human application. The newer ß alloys have been examined for their potential use as implants. These results serve as a preliminary baseline to characterize the best alloy system for a comprehensive long-term investigation.

Effect of povidone-iodine addition on the corrosion behavior of cp-Ti in normal saline.

The effect of various concentrations of povidone-iodine (PI) on the corrosion behavior of a commercially pure titanium alloy (Ti-1) has been investigated in normal saline solution to simulate the povidone-iodine addition in an oral environment. The open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization measurements have been used to characterize the electrochemical phenomena occurring on the alloy surface. The open circuit potential values for Ti-1 in various concentrations of PI shift considerably towards noble direction as compared to pure normal saline. In the potentiodynamic polarization curve for Ti-1 in various solutions, the cathodic current density has increased for all concentrations of PI and the anodic current density has decreased. Only the 0.1% PI concentration is able to inhibit corrosion of Ti-1 in normal saline and the other higher concentrations studied, accelerate corrosion. The EIS data for Ti-1 in normal saline and in various concentrations of PI follows a one time constant circuit, suggesting the formation of a single passive film on Ti-1 which is not altered by the addition of PI to normal saline.

Effect of granulocyte colony-stimulating factor on the incidence of threshold retinopathy of prematurity.

PURPOSE: To study the effect of granulocyte colony-stimulating factor (GCSF) on the incidence of threshold retinopathy of prematurity (ROP). METHODS: A retrospective chart review of all neonates who received GCSF at our neonatal intensive care unit over a period ranging from January 2003 to September 2007 was performed. Of the 213 patients identified, 50 patients with birth weight <1,500 g and gestational age <32 weeks were included in this study. The incidence of threshold ROP in this subset was compared to a control group (n = 161) obtained from Vermont Oxford Network ROP database over the same time period. The two data sets were cross-referenced to exclude any patient receiving GCSF from the control data. RESULTS: The average birth weight was 913 g in GCSF patients and 847 g in controls. The average dose of GCSF was 10.4 microg (range, 1.2-21.6 microg). The average age at administration of GCSF was 12 days after birth (range, 0-34 days). Out of 50 patients in the GCSF group, 5 (10%) required laser treatment, whereas in the contol group, 30 (18.6 %) required laser treatment; this difference was not statistically significant. CONCLUSIONS: There was a suggestion of a decreased incidence of threshold ROP, leading to reduced need for laser treatment, in patients who received GCSF, but the observed differences were not statistically significant. The authors anticipate that these findings will lead to further study of the upstream regulators of neovascularization.

Hang-back recession of inferior oblique muscle in V-pattern strabismus with inferior oblique overaction.

INTRODUCTION: Although hang-back recession has widely been used as a weakening procedure on extraocular muscles, its effectiveness has mostly been studied for rectus muscles. We report a surgical technique for recessing the inferior oblique muscle and evaluate its effectiveness in V-pattern strabismus with inferior oblique overaction (IOOA). METHODS: Fifteen patients with V-pattern strabismus and IOOA, 7 with V exotropia, and 8 with V esotropia underwent hang-back recession of inferior oblique muscle in addition to horizontal muscle surgery when required. The surgical technique consisted of free suspension of one or both inferior oblique muscles 10 mm along their physiological path using 6-0 polyglactin 910 sutures bridging the cut ends of muscle. RESULTS: The mean preoperative V pattern in the V-exotropia group was 22(Delta) +/- 6(Delta) and 25(Delta) +/- 7(Delta) in V-esotropia group. The mean correction of V pattern after a mean follow-up period of 8 +/- 1 months was 19(Delta) +/- 2(Delta) for the V-exotropia group and 22(Delta) +/- 7(Delta) months for the V-esotropia group. Mean correction of IOOA in the V-exotropia group was 18(Delta) +/- 5(Delta); in the V-esotropia group, mean correction was 20(Delta) +/- 6(Delta) in the right eye and 18(Delta) +/- 2(Delta) in the left eye. CONCLUSIONS: Hang-back recession of inferior oblique is another surgical procedure for correction of both V pattern and IOOA in V-pattern strabismus.

Evaluation of subjective and objective cyclodeviation following oblique muscle weakening procedures.

PURPOSE: To evaluate the subjective and objective cyclodeviational changes following different weakening procedures on superior and inferior oblique muscles. DESIGN: Comparative case series. MATERIALS AND METHODS: In a prospective institution based study, 16 cases of A pattern horizontal strabismus having superior oblique overaction were randomized to superior oblique weakening procedures: either silicon expander or translational-recession. Similarly, 20 cases of V pattern horizontal strabismus with inferior oblique overaction were randomized for inferior oblique weakening procedures: either 10 mm Fink's recession or modified Elliot and Nankin's anteropositioning. Cyclodeviation was assessed subjectively with the synoptophore and objectively using the fundus photograph before surgery and 3 months postoperatively. Change in cyclodeviation was measured by subjective and objective methods. The index of surgical effect (ISE) was defined as the net torsional change postoperatively. RESULTS: The difference between the extorsional change induced by the two superior oblique procedures, silicone expander (-6 degrees ) and translational recession (-11.3 degrees), was statistically significant (P=0.001). Translational recession caused more extorsional change (ISE=296%) than silicone expander surgery (ISE=107%). The two inferior oblique weakening procedures, Fink's recession (+2.5 degrees) and modified Elliot and Nankin's anteropositioning (+4.7 degrees) produced equitable amount of intorsional shift with no statistical difference (P=0.93). Objective measurements were significantly more than the subjective measurements. CONCLUSIONS: Different weakening procedures on oblique muscles produce different changes in cyclodeviation, which persists even up to 3 months. Subjective cyclodeviation is less than the objective measurements indicating partial compensation by sensorial adaptations.

Recurrence of amblyopia after occlusion therapy.

PURPOSE: To determine the stability of visual acuity (VA) after a standardized occlusion regimen in children with strabismic and/or anisometropic amblyopia. DESIGN: Retrospective, population-based, consecutive observational case series. PARTICIPANTS: Four hundred forty-nine patients younger than 10 years who underwent an occlusion trial for amblyopia and were observed until there was a recurrence of amblyopia or for a maximum of 1 year after decrease or cessation of occlusion therapy. METHODS: We performed a retrospective chart review of all patients treated by occlusion therapy for strabismic and/or anisometropic amblyopia at our institution over a 34-year period. Of the 1621 patients identified in our database, 449 met the eligibility criteria and were included in this study. Patients having at least a 2 logarithm of the minimum angle of resolution (logMAR)-level improvement in VA by optotypes or a change from unmaintained to maintained fixation preference during the course of occlusion therapy were included. A recurrence of amblyopia was defined as > or =2 logMAR levels of VA reduction or reversal of fixation preference within 1 year after a decrease or cessation of occlusion therapy. MAIN OUTCOME MEASURE: Recurrence of amblyopia after a decrease or cessation of occlusion therapy and its relationship with patient age and VA of the amblyopic eye at the time of decrease or cessation of occlusion therapy. RESULTS: Of 653 occlusion trials, 179 (27%) resulted in recurrence of amblyopia. The recurrence was found to be inversely correlated with patient age. There was no statistically significant association between the recurrence of amblyopia and VA of the amblyopic eye at the end of maximal occlusion therapy. CONCLUSIONS: There is a clinically important risk of amblyopia recurrence when occlusion therapy is decreased before the age of 10 years. The risk of recurrence is inversely correlated with age (P<0.0001).

Orbital magnetic resonance imaging of extraocular muscles in chronic progressive external ophthalmoplegia: specific diagnostic findings.

INTRODUCTION: Chronic progressive external ophthalmoplegia (CPEO) is characterized by slowly progressive bilateral ophthalmoplegia and blepharoptosis. Molecular diagnosis is problematic because sporadic mitochondrial DNA deletions can be causative. We sought findings using magnetic resonance imaging (MRI) that might support the diagnosis of CPEO. METHODS: Two men (ages 31 and 47 years) and 3 women (ages 40-49 years) with CPEO and symptom durations of 8 months to 28 years underwent high-resolution (2-mm slice thickness, 312 micron pixels), surface coil, T1-weighted orbital MRI in coronal planes. Images were analyzed quantitatively to determine extraocular muscle (EOM) sizes and were compared with 10 age- and gender-matched normal volunteers, one subject with myasthenia gravis, and with 30 subjects having EOM paralysis caused by oculomotor, trochlear,0 and abducens neuropathies. RESULTS: EOM function was clinically diminished in CPEO, most markedly for the superior rectus (SR) and levator muscles. All EOMs in CPEO exhibited unusual qualitative T1 MRI signal abnormalities. Unlike the profound EOM atrophy typical of neurogenic paralysis, anterior volumes of medial rectus, lateral rectus, and inferior rectus muscles in CPEO were not smaller than normal (p>0.003). Anterior volumes of the SR muscle-levator complex and superior oblique were significantly reduced (p<0.003). Denervated EOMs exhibited statistically significant volume reduction when compared with normal and CPEO groups. Volume of the SR muscle-levator complex was the same in subjects with CPEO and oculomotor palsies. CONCLUSIONS: CPEO is associated with minimal EOM volume reduction despite clinically severe weakness. This combination of findings may be specific for CPEO and could resolve the diagnostic dilemma in difficult cases.

Periosteal fixation in third-nerve palsy.

PURPOSE: We present a new technique of anchoring the eyeball to the nasal periosteum using a nonabsorbable suture in acquired isolated third-nerve paresis. METHODS: This was a case series of 4 consecutive adult subjects with isolated third-nerve paresis. After a 12-mm lateral rectus muscle recession in all 4 subjects, we passed 5-O double-armed polyester (NW683 Ethibond; Ethicon, Division of Johnson and Johnson Ltd., Aurangabad, India) on spatulated needles through the periosteum overlying the anterior lacrimal crest (exposed as in a Dacryocystorhinostomy procedure) at its superior part. The needles were brought anterior to the medial rectus muscle insertion and tightened enough to align the eye in 8-10 prism diopters adducted position. RESULTS: Ocular alignment in the primary gaze was satisfactory at 6-12 months of follow up. CONCLUSIONS: The use of a nonabsorbable polyester suture to anchor the globe to the nasal periosteum is an additional technique that holds promise to align the eyes in the primary gaze.