Evaluation of intraocular pressure according to corneal thickness before and after excimer laser corneal ablation for myopia.

Intraocular pressure is affected by corneal thickness and biomechanics. Following ablative corneal refractive surgery, corneal structural changes occur. The purpose of the study is to determine the relationship between the mean central corneal thickness (CCT) and the change in intraocular pressure measurements following various corneal ablation techniques, using different measurement methods. Two hundred myopic eyes undergoing laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) were enrolled into a prospective, non-randomized study. Corneal parameters examined included full ocular examination, measurement of CCT, corneal topography, corneal curvature and ocular refractivity. Intraocular pressure measurements were obtained using three different instruments-non-contact tonometer, Goldmann applanation tonometer and TonoPen XL (TonoPen-Central and TonoPen-Peripheral). All measurements were performed pre-operatively and 4 months post-operatively. Post-operative intraocular pressure was significantly lower than pre-operative values, with all instruments (p value < 0.001, Student's t-test). The post-operative intraocular pressure decrease was smallest using the Tonopen-XL compared to the Goldmann applanation tonometer and non-contact tonometer (p value < 0.001, ANOVA). Intraocular pressure readings are significantly reduced following corneal ablation surgery. We determined in our myopic patient cohort that the TonoPen XL intraocular pressure measurement method is the least affected following PRK and LASIK as compared to other techniques.

Surgical results in the management of advanced primary congenital glaucoma in a rural pediatric population.

OBJECTIVE: To present the anatomic and functional results of surgical treatment for advanced primary congenital glaucoma (PCG) in a rural setting. DESIGN: Retrospective, observational case series. PARTICIPANTS: Forty eyes of 22 consecutive patients diagnosed with PCG and who underwent surgical treatment. METHODS: All eyes underwent surgical treatment for PCG. Type of surgery and postoperative complications were noted. We examined anatomic and functional indices before and after the operation. MAIN OUTCOME MEASURES: Visual acuity (VA), intraocular pressure (IOP), refractive spherical error, cup-to-disc ratio (CDR), and horizontal corneal diameter (HCD). RESULTS: Average age at the time of surgery was 3.3 years (range, 0.4-10) and the mean follow-up was 6 months (range, 1-11). 15% showed marked lens dislocation owing to the severe buphthalmos at presentation. Preoperative IOP was 54 ± 2 mmHg, HCD was 15.1 ± 0.3 mm, and CDR (when visible) was 0.8 ± 0.02. Surgical intervention included 31 trabeculotomies, 6 Ahmed Glaucoma Valve implants, 1 goniotomy, and 2 eviscerations. Serious complications were noted in 4 eyes. Final postoperative IOP was 23 ± 2 mmHg (P < 0.0001). Patients were significantly more likely to have ambulatory VA (following objects or better) after operation (18% vs 64%; P < 0.0001). CONCLUSIONS: Our surgical outcomes in children with advanced PCG demonstrated moderate overall improvement in IOP and modest improvement of VA. Deep deprivation amblyopia, severe disease manifestation at presentation, opaque corneas, and frequent lens dislocation limited the possible success. These data further signify the need for effective, timely screening of children and prompt recognition by health care workers to reduce the rate of avoidable blindness in developing countries.

The postoperative occurrence of cardio-respiratory adverse events in small infants undergoing gastrointestinal surgery: a prospective comparison of general anesthesia and combined spinal-epidural anesthesia.

INTRODUCTION: This study was designed to compare the occurrences of postoperative cardio-respiratory adverse events during an 8-day follow-up period in the neonatal intensive care unit in small infants who underwent elective gastrointestinal surgery under general and combined spinal epidural anesthesia. METHODS: Fifty infants who underwent elective primary gastrointestinal surgery were randomly divided into two anesthetic techniques. General anesthesia (25 patients) and combined spinal-epidural anesthesia (25 patients). The frequency and types of postoperative cardiovascular and respiratory adverse events in the two groups were recorded and compared during an 8-day follow-up period in the neonatal intensive care unit. RESULTS: The total number of postoperative respiratory adverse events and the number of infants who experienced at least one respiratory adverse event were statistically more in infants anesthetised by general anesthesia than in infants who were anesthetised by combined spinal-epidural anesthesia, respectively (p < 0.0001) and (RR = 2.5; 95% CI 1.2-5.3). There were significantly more cardiovascular adverse events in the general anesthesia infants than in the combined spinal-epidural anesthesia (p = 0.005). These adverse cardiovascular events were also more resistant to treatment in the general anesthesia infants than in the combined spinal-epidural anesthesia infants (p = 0.001). CONCLUSION: Compared to general anesthesia, combined spinal-epidural anesthesia reduces the frequency of postoperative respiratory adverse events and improves the postoperative cardiovascular stability in small infants who undergo elective gastrointestinal surgery.

Treatment of dry eye syndrome with orally administered CF101: data from a phase 2 clinical trial.

OBJECTIVE: To explore the safety and efficacy of CF101, an A(3) adenosine receptor agonist, in patients with moderate to severe dry eye syndrome. DESIGN: Phase 2, multicenter, randomized, double-masked, placebo-controlled, parallel-group study. PARTICIPANTS: Sixty-eight patients completed the study, 35 patients in the placebo group and 33 patients in the CF101 group. INTERVENTION: Patients were treated orally with either 1 mg CF101 pills or matching vehicle-filled placebo pills, given twice daily for 12 weeks, followed by a 2-week posttreatment observation. MAIN OUTCOME MEASURES: An improvement of more than 25% over baseline at week 12 in one of the following parameters: (1) tear break-up time (BUT); (2) superficial punctate keratitis assessed by fluorescein staining results; and (3) Schirmer tear test 1 results. Clinical laboratory safety tests, ophthalmic examinations, intraocular pressure (IOP) measurements, electrocardiographic evaluations, vital sign measurements, and monitoring of adverse events. RESULTS: A statistically significant increase in the proportion of patients who achieved more than 25% improvement in the corneal staining and in the clearance of corneal staining was noted between the CF101-treated group and the placebo group. Treatment with CF101 resulted in a statistically significant improvement in the mean change from baseline at week 12 of the corneal staining, BUT, and tear meniscus (TM) height in the CF101-treated group. CF101 was well tolerated and exhibited an excellent safety profile with no serious adverse events. A statistically significant decrease from baseline was observed in the IOP of the CF101-treated group in comparison with the placebo group. CONCLUSIONS: CF101, given orally, induced a statistically significant improvement in the corneal staining and an improvement in the BUT and TM in patients with moderate to severe dry eye syndrome. The drug was very well tolerated. These data and the anti-inflammatory characteristic of CF101 support further study of the drug as a potential treatment for the signs and symptoms of dry eye syndrome. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

TGF-beta receptor-mediated albumin uptake into astrocytes is involved in neocortical epileptogenesis.

It has long been recognized that insults to the cerebral cortex, such as trauma, ischaemia or infections, may result in the development of epilepsy, one of the most common neurological disorders. Human and animal studies have suggested that perturbations in neurovascular integrity and breakdown of the blood-brain barrier (BBB) lead to neuronal hypersynchronization and epileptiform activity, but the mechanisms underlying these processes are not known. In this study, we reveal a novel mechanism for epileptogenesis in the injured brain. We used focal neocortical, long-lasting BBB disruption or direct exposure to serum albumin in rats (51 and 13 animals, respectively, and 26 controls) as well as albumin exposure in brain slices in vitro. Most treated slices (72%, n = 189) displayed hypersynchronous propagating epileptiform field potentials when examined 5-49 days after treatment, but only 14% (n = 71) of control slices showed similar responses. We demonstrate that direct brain exposure to serum albumin is associated with albumin uptake into astrocytes, which is mediated by transforming growth factor beta receptors (TGF-betaRs). This uptake is followed by down regulation of inward-rectifying potassium (Kir 4.1) channels in astrocytes, resulting in reduced buffering of extracellular potassium. This, in turn, leads to activity-dependent increased accumulation of extracellular potassium, resulting in facilitated N-methyl-d-aspartate-receptor-mediated neuronal hyperexcitability and eventually epileptiform activity. Blocking TGF-betaR in vivo reduces the likelihood of epileptogenesis in albumin-exposed brains to 29.3% (n = 41 slices, P < 0.05). We propose that the above-described cascade of events following common brain insults leads to brain dysfunction and eventually epilepsy and suggest TGF-betaRs as a possible therapeutic target.

Lasting blood-brain barrier disruption induces epileptic focus in the rat somatosensory cortex.

Perturbations in the integrity of the blood-brain barrier have been reported in both humans and animals under numerous pathological conditions. Although the blood-brain barrier prevents the penetration of many blood constituents into the brain extracellular space, the effect of such perturbations on the brain function and their roles in the pathogenesis of cortical diseases are unknown. In this study we established a model for focal disruption of the blood-brain barrier in the rat cortex by direct application of bile salts. Exposure of the cerebral cortex in vivo to bile salts resulted in long-lasting extravasation of serum albumin to the brain extracellular space and was associated with a prominent activation of astrocytes with no inflammatory response or marked cell loss. Using electrophysiological recordings in brain slices we found that a focus of epileptiform discharges developed within 4-7 d after treatment and could be recorded up to 49 d postoperatively in >60% of slices from treated animals but only rarely (10%) in sham-operated controls. Epileptiform activity involved both glutamatergic and GABAergic neurotransmission. Epileptiform activity was also induced by direct cortical application of native serum, denatured serum, or albumin-containing solution. In contrast, perfusion with serum-adapted electrolyte solution did not induce abnormal activity, thereby suggesting that the exposure of the serum-devoid brain environment to serum proteins underlies epileptogenesis in the blood-brain barrier-disrupted cortex. Although many neuropathologies entail a compromised blood-brain barrier, this is the first direct evidence that it may have a role in the pathogenesis of focal cortical epilepsy, a common neurological disease.

A review of primary congenital glaucoma in the developing world.

Primary congenital glaucoma is the most common type of infantile glaucoma, yet it remains a relatively rare disease. Treatment is principally surgical, and management lasts a lifetime. In the developing world, delayed diagnosis, limited treatment, and inadequate follow-up lead to a heavier burden on the patient and community. We highlight the epidemiology and genetics of the disease, its current management and prognosis, and the limitations facing both providers and patients in the developing world. Further efforts are necessary to provide effective, timely screening of children and allocate adequate resources to allow health care workers to reduce the rate of avoidable blindness in developing countries.

Novel fluorescein angiography-based computer-aided algorithm for assessment of retinal vessel permeability.

PURPOSE: To present a novel method for quantitative assessment of retinal vessel permeability using a fluorescein angiography-based computer algorithm. METHODS: Twenty-one subjects (13 with diabetic retinopathy, 8 healthy volunteers) underwent fluorescein angiography (FA). Image pre-processing included removal of non-retinal and noisy images and registration to achieve spatial and temporal pixel-based analysis. Permeability was assessed for each pixel by computing intensity kinetics normalized to arterial values. A linear curve was fitted and the slope value was assigned, color-coded and displayed. The initial FA studies and the computed permeability maps were interpreted in a masked and randomized manner by three experienced ophthalmologists for statistical validation of diagnosis accuracy and efficacy. RESULTS: Permeability maps were successfully generated for all subjects. For healthy volunteers permeability values showed a normal distribution with a comparable range between subjects. Based on the mean cumulative histogram for the healthy population a threshold (99.5%) for pathological permeability was determined. Clear differences were found between patients and healthy subjects in the number and spatial distribution of pixels with pathological vascular leakage. The computed maps improved the discrimination between patients and healthy subjects, achieved sensitivity and specificity of 0.974 and 0.833 respectively, and significantly improved the consensus among raters for the localization of pathological regions. CONCLUSION: The new algorithm allows quantification of retinal vessel permeability and provides objective, more sensitive and accurate evaluation than the present subjective clinical diagnosis. Future studies with a larger patients' cohort and different retinal pathologies are awaited to further validate this new approach and its role in diagnosis and treatment follow-up. Successful evaluation of vasculature permeability may be used for the early diagnosis of brain microvascular pathology and potentially predict associated neurological sequelae. Finally, the algorithm could be implemented for intraoperative evaluation of micovascular integrity in other organs or during animal experiments.

Outcomes of pediatric cataract surgery at a tertiary care center in rural southern Ethiopia.

OBJECTIVE: To evaluate the etiologies, management, and outcomes of pediatric cataracts in a rural sub-Saharan African setting. METHODS: A retrospective, consecutive case series of patients presenting to a tertiary referral center in southern Ethiopia during a 13-month period. All patients underwent clinical examination, were diagnosed as having cataract on the basis of standard clinical assessment, and immediately underwent surgical management. Visual acuity results were grossly divided into ambulatory and nonambulatory vision according to patient age and cooperation. RESULTS: Ninety-one eyes of 73 consecutive patients (57 boys and 16 girls) were included in the study. The mean (SEM) age at diagnosis was 7.1 (0.5) years (range, 0.5-15 years). Fifty-five patients had unilateral cataract and 18 had bilateral cataract. Cataracts were categorized according to the etiologic cause: congenital (n = 50), traumatic (n = 33), congenital glaucoma-related (n = 3), partially absorbed cataracts (n = 3), and congenital rubella infections (n = 2). At presentation, visual acuity ranged from 6/60 to light perception, with 13 eyes (14%) having ambulatory vision (better than hand motion). The mean postoperative visual acuity was significantly improved, ranging from light perception to 6/9. Seventy-five eyes (82%) achieved ambulatory vision. Of the 61 eyes with an implanted intraocular lens, 56 (92%) reached ambulatory visual acuity following surgery. This was significantly greater than preoperative visual acuity results (P < .001). CONCLUSIONS: The underlying cause and management of pediatric cataracts in the developing world can differ significantly from that commonly reported in the literature. The effects of appropriate intervention on both visual outcome and associated survival statistics may be profound.

Blood-brain barrier breakdown following traumatic brain injury: a possible role in posttraumatic epilepsy.

Recent animal experiments indicate a critical role for opening of the blood-brain barrier (BBB) in the pathogenesis of post-traumatic epilepsy (PTE). This study aimed to investigate the frequency, extent, and functional correlates of BBB disruption in epileptic patients following mild traumatic brain injury (TBI). Thirty-seven TBI patients were included in this study, 19 of whom suffered from PTE. All underwent electroencephalographic (EEG) recordings and brain magnetic resonance imaging (bMRI). bMRIs were evaluated for BBB disruption using novel quantitative techniques. Cortical dysfunction was localized using standardized low-resolution brain electromagnetic tomography (sLORETA). TBI patients displayed significant EEG slowing compared to controls with no significant differences between PTE and nonepileptic patients. BBB disruption was found in 82.4% of PTE compared to 25% of non-epileptic patients (P = .001) and could be observed even years following the trauma. The volume of cerebral cortex with BBB disruption was significantly larger in PTE patients (P = .001). Slow wave EEG activity was localized to the same region of BBB disruption in 70% of patients and correlated to the volume of BBB disrupted cortex. We finally present a patient suffering from early cortical dysfunction and BBB breakdown with a gradual and parallel resolution of both pathologies. Our findings demonstrate that BBB pathology is frequently found following mild TBI. Lasting BBB breakdown is found with increased frequency and extent in PTE patients. Based on recent animal studies and the colocalization found between the region of disrupted BBB and abnormal EEG activity, we suggest a role for a vascular lesion in the pathogenesis of PTE.

Management of recurrent pterygium with intraoperative mitomycin C and conjunctival autograft with fibrin glue.

PURPOSE: To evaluate the safety and efficacy of using fibrin glue in cases of recurrent pterygium treated with pterygium excision and conjunctival autograft combined with mitomycin C. DESIGN: Retrospective, interventional case series. METHODS: The charts of 28 patients with recurrent pterygium who had undergone pterygium excision and conjunctival autograft using fibrin glue to secure the graft combined with intraoperative mitomycin C at a corneal service in a university teaching hospital were reviewed. Inclusion criteria were recurrent pterygium that had undergone at least 1 previous surgical excision and patients who had completed a regular postoperative follow-up of at least 12 months. Outcome measures included mean best-corrected visual acuity (BCVA) and intraoperative and postoperative complications. RESULTS: The mean age of the cohort was 49.7 years. There were no intraoperative complications. Early postoperative total graft dehiscence developed in 1 eye that underwent repositioning with glue and sutures. One eye had mild graft dehiscence and required no surgical intervention. One eye had a conjunctival cyst on the graft that did not require intervention. No significant change was observed in BCVA. At a mean follow-up of 26.5 months, there was 1 case of recurrence. CONCLUSIONS: Pterygium excision and conjunctival autograft using fibrin glue to secure the graft combined with intraoperative mitomycin C seems to be a safe and effective surgical option for treating recurrent pterygium. However, a larger cohort with longer follow-up may be required to assess the recurrence rate of this method.

Fusarium keratitis acquired during travel to Namibia.

Fungal infections in travelers are rare. Fusariosis has recently become an important infection of immunocompromised patients. Herein, we describe the case of an immunocompetent traveler who contracted Fusarium keratitis while in Africa.

Collagen cross-linking: Strengthening the unstable cornea.

Corneal ectasia, a weakening of corneal integrity, occurs both due to acquired and congenital conditions such as keratoconus. It is a progressing condition that affects both visual acuity, and corneal stability. Various methods exist for correcting this impairment, however none address the inherit pathology, an increase laxity of the corneal stroma. Collagen cross-linking, a new, minimally invasive method, aims to strengthen the stroma by inducing cross links between neighboring collagen fibers. This method results in an increase in corneal tensile strength, with no medium term adverse effects on its normal architecture. Clinically, treated patients display improvement in both visual acuity and keratometric readings. This method may provide clinicians with easily accessible tools to stop the progression, and even correct visual deterioration due to corneal ectasia. Here we review the current information regarding this new method, as well as discuss its potential benefits and downfalls.