DETERMINATION OF CORNEAL POWER AFTER REFRACTIVE SURGERY WITH EXCIMER LASER: A CONCISE REVIEW

Refractive surgery with excimer laser has been a very common surgical procedure worldwide during the last decades. Currently, patients who underwent refractive surgery years ago are older, with a growing number of them now needing cataract surgery. To establish the power of the intraocular lens to be implanted in these patients, it is essential to define the true corneal power. However, since the refractive surgery modified the anterior, but not the posterior surface of the cornea, the determination of the corneal power in this group of patients is challenging. This article reviews the different sources of error in finding the true corneal power in these cases, and comments on several approaches, including the clinical history method as described originally by Holladay, and a modified version of it, as well as new alternatives based on corneal tomography, using devices that are able to measure the actual anterior and posterior corneal curvatures, which have emerged in recent years to address this issue.

VISUAL OUTCOMES, CONTRAST SENSITIVITY, AND SATISFACTION WITH MULTIFOCAL INTRAOCULAR LENS BLENDED TECHNIQUE: LATE MID-TERM RESULTS

PURPOSE

To describe clinical visual outcomes, spectacle independence, and patient satisfaction after cataract surgery with blending implantation of ReSTOR (Alcon laboratories) multifocal intraocular lenses.

MATERIAL AND METHODS

A single-arm, non-randomized prospective study assessed patients undergoing cataract surgery with ReSTOR® +2.50 intraocular lens in the dominant eye and +3.00 add in the fellow eye between January 2015 to January 2020.

RESULTS

In total, 47 patients (94 eyes) were enrolled, 28 women and 19 men. The average age at surgery time was 64 ±8 years, average postoperative follow-up was 45.4 ±7.0 months, with a minimum of 18.9 months. Postoperative binocular uncorrected distance visual acuity (UDVA) was on average 0.07 logMar (Snellen 20/24), uncorrected binocular intermediate visual acuity at 65 cm was 0.07 logMar (20/24), uncorrected binocular near visual acuity at 40 cm was 0.06 logMar (20/23). Contrast sensitivity under photopic and scotopic conditions, with and without glare, remained at the upper limit of normality. 98% of patients were quite satisfied or very satisfied. 87% did not require glasses for any activities, either at distant vision, nor at near vision.

CONCLUSIONS

Cataract surgery with ReSTOR® IOL blended vision showed medium-term satisfactory visual results, achieving spectacle independence and a high level of satisfaction.

Determination of Corneal Power after Refractive Surgery with Excimer Laser: A Concise Review

Refractive surgery with excimer laser has been a very common surgical procedure worldwide during the last decades. Currently, patients who underwent refractive surgery years ago are older, with a growing number of them now needing cataract surgery. To establish the power of the intraocular lens to be implanted in these patients, it is essential to define the true corneal power. However, since the refractive surgery modified the anterior, but not the posterior surface of the cornea, the determination of the corneal power in this group of patients is challenging. This article reviews the different sources of error in finding the true corneal power in these cases, and comments on several approaches, including the clinical history method as described originally by Holladay, and a modified version of it, as well as new alternatives based on corneal tomography, using devices that are able to measure the actual anterior and posterior corneal curvatures, which have emerged in recent years to address this issue.

SEVERE NEAR REFLEX SPASM IN A HEALTHY TEENAGER. A CASE REPORT

INTRODUCTION

Spasm of the near reflex usually includes accommodative spasm, esophoria/tropia, and different degrees of miosis. Patients usually refer to distance blurred and fluctuating vision, ocular discomfort, and headaches. The diagnosis is established with refraction with and without cycloplegia; most of the cases have a functional etiology. However, some cases require neurological conditions to be ruled out; cycloplegics have an important diagnostic and therapeutic role.

PURPOSE

To describe a case of bilateral severe accommodative spasm in a healthy 14-year-old teenager.

CASE PRESENTATION

A 14-year-old boy with progressive diminished visual acuity attended for YSP consultation. The diagnosis of bilateral spasm of the near reflex was made, based on a gap refraction of 9.75 D between retinoscopy with and without cycloplegia and esophoria with normal keratometry and axial length. The spasm was eliminated with 2 drops of cycloplegic in each eye separated by 15 days; no clear etiology was found other than the start of school.

CONCLUSION

Clinicians should be aware of pseudomyopia, especially in children with acute changes in visual acuity, who are usually exposed to myopigenic environmental factors that induce overstimulation of the parasympathetic third cranial nerve's innervation.

DETERMINATION OF CORNEAL POWER AFTER REFRACTIVE SURGERY WITH EXCIMER LASER: A CONCISE REVIEW

Refractive surgery with excimer laser has been a very common surgical procedure worldwide during the last decades. Currently, patients who underwent refractive surgery years ago are older, with a growing number of them now needing cataract surgery. To establish the power of the intraocular lens to be implanted in these patients, it is essential to define the true corneal power. However, since the refractive surgery modified the anterior, but not the posterior surface of the cornea, the determination of the corneal power in this group of patients is challenging. This article reviews the different sources of error in finding the true corneal power in these cases, and comments on several approaches, including the clinical history method as described originally by Holladay, and a modified version of it, as well as new alternatives based on corneal tomography, using devices that are able to measure the actual anterior and posterior corneal curvatures, which have emerged in recent years to address this issue.

Cystoid Macular Edema after an uncomplicated Gonioscopy- Assisted Transluminal Trabeculotomy on a previously vitrec- tomized patient

PURPOSE

The main purpose of this study was to report a case of cystoid macular edema (CME) after gonioscopy-assisted transluminal trabeculotomy (GATT).

METHODS

We describe the case of a 73-year-old woman with ocular hypertension and history of cataract surgery combined with posterior vitrectomy and epiretinal membrane peeling 2 years before, who developed CME after uncomplicated GATT procedure.

RESULTS

Uneventful GATT surgery was performed in an eye with ocular hypertension. A month after GATT surgery, the patient com-plained of blurry vision. Best corrected visual acuity had deteriorated from 20/20 on Snellen chart, to 20/70. The patient was diagnosed with CME. Treatment with topical non-steroidal anti-inflammatory drug (NSAID) and topical corticosteroids for one month, and oral carbonic anhydrase inhibitor for one week achieved a total CME regression with recovery of a normal macular and foveal architecture.

CONCLUSIONS

Surgery-induced CME may occur following stand-alone microinvasive glaucoma surgery (MIGS) such as GATT. It would be worthwhile to conduct studies to explore whether the prophylactic use of NSAID and corticosteroids is justified.

DETERMINATION OF FACTORS ASSOCIATED WITH LONG-TERM ENDOTHELIAL LOSS AND REFRACTIVE RESULT IN PATIENTS WITH ARTISAN PHAKIC LENS

PURPOSE

To determine the changes in endothelial cell density, refractive results, and risk factors associated with endothelial loss in patients with irisclaw phakic intraocular lenses for myopia/myopic astigmatism (Artisan).

METHODOLOGY

Data collection was obtained from an existing database with information on patients with a phakic Artisan lens implant between 1998 and 2011 at the Virgilio Galvis Ophthalmology Centre, with at least 5 years of follow-up. As a second stage, an analysis was carried out to identify the change in endothelial cell density and its potential associated factors.

RESULTS

A total of 80 eyes with myopic errors were included with a follow-up of 11.9 + 3.48 years. The percentage of total loss of endothelial cells was greater than 25% of the preoperative density in 43.8% of the eyes. A postoperative annual loss > 1.6% was found in 47.0% of the eyes with that information available. 41 eyes (51%) had final endothelial density < 2000 cells/mm2, and 7 (8.8%) eyes had endothelial cell density < 1000 cells/mm2. Among the variables studied, no associated factors for long-term endothelial loss were found. During the course of the study, 8 (10%) phakic intraocular lenses were explanted, including 3 with accelerated endothelial loss, and another 2 with cataract associated and a significantly low endothelial density. The last mean spherical equivalent was -0.81 (±1.01 D), and the final uncorrected distance visual acuity was 0.45 logMar (Snellen 20/56).

CONCLUSION

Artisan-type phakic lenses are a good alternative for the correction of high myopic defects, with predictable refractive results in the long term. However, there is an increased loss of endothelial cells in the long term in a high percentage of patients. Strict postoperative follow-up, including endothelial evaluation, is required, and further studies are warranted.

SPONTANEOUS REGRESSION OF A PRIMARY IRIS STROMAL CYST IN A PATIENT WITH KERATOCONUS. A CASE REPORT

PURPOSE

To report the rare case of a 29-year-old male with a history of keratoconus, who presented with a primary iris stromal cyst which eventually showed spontaneous regression.

METHODS

Description of the clinical findings in the case of a 29-year-old male with a prior history of keratoconus, but no eye surgery or trauma, who consulted for an iris cyst in the left eye, diagnosed 9 months earlier.

CASE REPORT

Slit-lamp examination revealed mild dyscoria, and a large cyst in the inferior quadrant of the iris. Ultrasound biomicroscopy and anterior segment optical coherence tomography of the left eye confirmed the presence of a giant iris cyst with thin walls, in contact with the corneal endothelium. Corneal endothelial cell density in the inferior cornea (close to the cyst) was 1805 cells/mm2 and 2066 cells/mm2 in the central area. After considering the risk of anterior chamber epithelial downgrowth following any surgical procedure of the cyst, the patient received conservative management. In the following months, the patient presented with 3 episodes of anterior uveitis, managed with topical corticosteroids. Finally, at approx. 21 months after the initial diagnosis, the cyst presented spontaneous regression. Anterior segment optical coherence tomography confirmed the absence of fluid inside the cyst remnants and the final endothelial cell densities evidenced endothelial cell loss (inferior cornea 738 cells/mm2 and central cornea 1605 cells/mm2).

CONCLUSION

Conservative management should be considered in patients with cysts that show slow progression and are distant from the visual axis, in order to minimise the risk of complications following any surgical procedure of the cyst. In addition, the present case is one of the few of primary stromal iris cysts with spontaneous regression reported in the literature.

Estimation of ocular axial length with optometric parameters is not accurate

Myopia is a worldwide major public concern, aside from the visual disturbance needing optical correction, myopia may be associated with open angle glaucoma, retinal detachment and myopic maculopathy. The higher the myopia the higher the risk for retinal associated comorbidities, and the axial length is the more important measure to estimate risk of visual impairment. Recently a formula to predict axial length using spherical equivalent and keratometry was proposed, with the intention of categorizing the risk of visual impairment with Tideman et al. classification.

PURPOSE

To evaluate the accuracy of an axial length prediction formula in a Colombian population 8-17 years old.

METHODS

Children from MIOPUR study with optical biometer axial length measure (AL), manifest refraction and keratometry were included in the analysis. Predicted axial length (PAL) was calculated with the prediction formula. A Bland-Altman assessment was conducted, and the concordance correlation coefficient was measured. Proposed classification of AL to establish risk of visual loss was used with measured AL and with PAL. The percentage of eyes misclassified was then established.

RESULTS

A total of 2129 eyes were included in the analysis. Mean difference of axial length (actual AL minus PAL) was -0.516 mm (-1.559 mm - 0.528 mm). Concordance correlation coefficient (CCC) of 0.656 (IC95 0.636-0.675) was found between the real AL and PAL. PAL differed from measured AL by 1 mm or more in 16.58 %, and by 2 mm or more, in 0.61 % of the eyes. In myopic eyes, PAL was in average 0.426 mm longer than the AL actually measured with CCC of 0.714 (IC95 0.666-0.761). PAL differed from measured AL by 1 mm or more in 21.92 %, and by 2 mm or more, in 0.45 % of the myopic eyes. The study revealed that 15.03 % of all eyes, and 29.81 % of myopic eyes, were misclassified when PAL was used.

CONCLUSIONS

The proposed axial length prediction formula was not accurate, and it did not adequately classify risk of visual impairment in myopic eyes in a group of Colombian children. We consider that it is not possible to predict the axial length based only on optometric data, such as the corneal radius of curvature and the spherical equivalent. This is very possibly related to the variability of crystalline lens power within a population.

PHOTOREFRACTIVE SURGERY WITH EXCIMER LASER AND ITS IMPACT ON THE DIAGNOSIS AND FOLLOW-UP OF GLAUCOMA. A REVIEW

Excimer laser refractive surgery is a procedure performed worldwide to solve refractive errors and reduce dependence on glasses or contact lenses. There has been an increase in the number of procedures performed around the world. Myopia is the most common indication for corneal photorefractive surgery. Myopic patients have a higher risk of developing some type of glaucoma in their lifetime, such as primary open-angle glaucoma and others. Refractive surgery ablates central corneal stromal tissue, altering its thickness and biomechanics, which in turn makes it difficult to accurately measure intraocular pressure (IOP), since it underestimates it. This underestimation of IOP may delay the diagnosis of de novo glaucoma in patients with a history of refractive surgery. Each patient who wishes to undergo corneal refractive surgery should undergo a thorough glaucoma examination in order to monitor and detect the possible development and / or progression of glaucoma. A very useful practical approach is to perform a series of IOP measurements before and after surgery, when the eye is already stable, and the difference between the averages of the two sets of readings can then be used as a personalised correction factor for postoperative IOP monitoring in that eye. Also, if there is any suspicion of a possible glaucoma, paraclinical tests, such as coherent optical tomography of the retinal nerve fibre layer (RNFL), visual fields and photos of the optic nerve should be requested. All this data prior to refractive surgery should be provided to these patients, so that they can save it and give it to their treating ophthalmologists in the future.

Malignant transformation of a conjunctival keratoacanthoma requiring enucleation

PURPOSE

We report a rare case of rapid transformation of a conjunctival keratoacanthoma (KA) into a highly aggressive squamous cell carcinoma requiring enucleation. To our knowledge, this is the second such case reported in the literature.

METHODS

Case report.

RESULTS

A 73-year-old man presented with a recurrent conjunctival lesion in the right eye. A slit lamp examination revealed a hyperkeratotic lesion in the limbar conjunctiva adhered to deep planes but with no ocular involvement. An incisional biopsy was performed because an area of scleromalacia was observed underlying the lesion. Histological findings were consistent with conjunctival KA. One week later, a raised lesion was observed invading the anterior chamber. Histological examination of another excisional biopsy specimen indicated conjunctival squamous cell carcinoma. The right eye was enucleated. Histological analysis confirmed intraocular tumor invasion. Complete clinical remission was observed over one year of follow up.

CONCLUSIONS

Although conjunctival keratoacanthoma is normally benign, it is important to correctly differentiate between KA and squamous cell carcinoma, and closely monitor the eye after surgery because of the rare possibility of recurrence or conversion to squamous cell carcinoma. Immunohistochemistry could help in the diagnosis and management of dubious cases.

Synthesis of salt-stable fluorescent nanoparticles (quantum dots) by polyextremophile halophilic bacteria

Here we report the biological synthesis of CdS fluorescent nanoparticles (Quantum Dots, QDs) by polyextremophile halophilic bacteria isolated from Atacama Salt Flat (Chile), Uyuni Salt Flat (Bolivia) and the Dead Sea (Israel). In particular, a Halobacillus sp. DS2, a strain presenting high resistance to NaCl (3-22%), acidic pH (1-4) and cadmium (CdCl2 MIC: 1,375 mM) was used for QDs biosynthesis studies. Halobacillus sp. synthesize CdS QDs in presence of high NaCl concentrations in a process related with their capacity to generate S2- in these conditions. Biosynthesized QDs were purified, characterized and their stability at different NaCl concentrations determined. Hexagonal nanoparticles with highly defined structures (hexagonal phase), monodisperse size distribution (2-5 nm) and composed by CdS, NaCl and cysteine were determined by TEM, EDX, HRXPS and FTIR. In addition, QDs biosynthesized by Halobacillus sp. DS2 displayed increased tolerance to NaCl when compared to QDs produced chemically or biosynthesized by non-halophilic bacteria. This is the first report of biological synthesis of salt-stable QDs and confirms the potential of using extremophile microorganisms to produce novel nanoparticles. Obtained results constitute a new alternative to improve QDs properties, and as consequence, to increase their industrial and biomedical applications.

Antibiotic resistance profile in eye infections in a reference centre in Floridablanca, Colombia

BACKGROUND AND OBJECTIVE

In view of the increasing bacterial resistance to antibiotics, it is necessary to determine it locally in order to serve as a guide in clinical management. The purpose of this study was to characterise the pattern of antibiotic sensitivity in cases of eye infections in a third level ophthalmological institution in Floridablanca (Colombia).

MATERIALS AND METHODS

An observational cross-sectional study in which an analysis was made of the culture and antibiogram reports of specimens taken from cases of conjunctivitis, infectious keratitis, and endophthalmitis between January 2013 and June 2016.

RESULTS

A total of 833 specimens were positive for bacteria. Considering both gram-positive and gram-negative microorganisms gentamicin, tobramycin, and ciprofloxacin showed high resistance rates (64.4%, 40.3%, and 29.1%, respectively). Moxifloxacin, vancomycin, imipenem, and gatifloxacin showed low percentages of resistance: 2.6%, 2.1%, 0.6%, and 0.4%, respectively. When comparing the results with previous studies in our institution, there was a decrease in sensitivity to the fourth-generation quinolones and imipenem, especially within the gram-negative ones.

CONCLUSION

Fourth generation quinolones, imipenem and vancomycin continue to have a low in vitro resistance to bacteria that cause eye infections. However, there was a tendency to an increase in the resistance of gram-negative bacteria. Measures should be taken to try to control this phenomenon, and consider possible antimicrobial therapy alternatives to infections caused by these microorganisms.

Mycotic keratitis caused by Scedosporium apiospermum in an immunocompetent patient

CLINICAL CASE

A 51 year-old immunocompetent male was referred due to presenting with a large corneal ulcer with hypopyon in the right eye. Topical amphotericin B, fluconazole and moxifloxacin, as well as oral itraconazole were initially indicated. Following the report of mycotic structures on staining, topical natamycin was started. The result of the culture was reported two weeks later as, Scedosporium apiospermum (S. apiospermum), and topical voriconazole was then added. The response to treatment was very slow, and took five weeks after receiving triple therapy (natamycin, voriconazole and fluconazole) and one dose of intrastromal voriconazole, for the hypopyon to disappear. The final outcome was successful, achieving healing of the ulcer. The patient is waiting for a corneal transplant.

DISCUSSION

A microbiological study is essential in patients in whom fungal keratitis is suspected. The treatment of choice against S. apiospermum is with voriconazole, but the combination of various antifungal agents may be required.

Topical insulin in neurotrophic keratopathy after resection of acoustic neuroma

CASE REPORT

A patient with a history of surgical resection of an acoustic neuroma presented with involvement of both the left facial nerve and the left trigeminal nerve. She initially consulted for exposure keratitis, but two weeks later presented with an infectious keratitis. After taking the corneal sample, she presented with persistent epithelial defect, which did not respond to medical management. Topical insulin was indicated, and a decrease in the area of the lesion was seen in the following 5 days. A therapeutic contact lens was also placed at that time and finally, two weeks after the initiation of insulin, the epithelial defect completely closed.

DISCUSSION

This was a complex case due to the confluence of facial paralysis, neurotrophic keratitis, and infectious keratitis, which finally had a successful outcome. Topical insulin can be an effective adjuvant therapy in cases of neurotrophic ulcers that do not respond to standard therapy.

Application of botulinum toxin in Horner's muscle for the treatment of dry eye

OBJECTIVE/METHODS

The aim of this study is to describe the use of botulinum toxin to increase tear retention in patients with dry eye, using the description of 2 cases.

RESULTS

Patients with moderate to severe dry eye that were given an injection of type A botulinum toxin in the Horner's muscle. The results at one month and 3 months are reported. An assessment was made of the subjective perception of the patient as regards any improvement, as well as taking into account, the Ocular Surface Disease Index, superficial punctate keratitis, and the time of the tear rupture and tear meniscus. A significant improvement was observed in the subjective perception of the patient, the Ocular Surface Disease Index, superficial punctate keratitis, and the time of the tear rupture and tear meniscus at one month after treatment, and the good results still being maintained at the third month. There were no adverse events.

DISCUSSION

The use of type A botulinum toxin can be considered as an alternative to increase tear retention in moderate to severe dry eye, with a good response during the first month, with an acceptable response still being maintained at the third month. Given the temporary effect of the drug, further treatments would be required.

Risk factors for infectious pancreatic necrosis in farmed Chilean Atlantic salmon (Salmo salar L.) from 2010 to 2013

Infectious pancreatic necrosis (IPN) is a widespread and economically devastating fish disease caused by infection with a virus referred to as IPN virus (IPNv). In Chile, the disease is endemic and prevalent in both fresh- and salt-water farms affecting cultured salmonids, mainly Atlantic salmon. Here, we present the results of a retrospective cohort study of Atlantic salmon farms stocked between 2010 and 2013, aimed at quantifying the extent to which certain epidemiological factors influence the time interval between stocking and onset of IPN mortality (time to mortality, ttm) in marine farms. Six variables were retained in a final multivariable Cox proportional hazard model. Compared to the 2010 stocking year, ttm was shorter for salmon stocked in years 2012 (HR = 2.1; p = 0.005) and 2013 (HR = 4.3; p = 0.01). The number of salmon farms within a 10-km radius (HR = 1.07; p = 0.002), positive report of IPN in the previous production cycle (HR = 1.95; p = 0.006), three or more smolt batches (HR = 2.27; p < 0.001), and positive report of mortality attributable to BKD (HR = 2.02; p < 0.001) were also associated with low ttm; conversely, ttm was longer for farms that stocked heavier fish (HR = 0.94; p = 0.001). The results presented here were consistent with early studies of IPN epidemiology in Norway and Scotland. Some of the risk factors identified in this study also influenced the risk for other diseases, such as infectious salmon anemia, suggesting that implementation of selected management practices may help to mitigate the burden of important infectious diseases of salmon in Chile.

UUnilateral corneal edema caused by a hidden foreign body

CASE REPORT

A middle-aged adult male was referred to our institution due to unilateral corneal edema for a possible corneal transplant. At first, the patient denied a history of trauma. A small foreign body, which had been overlooked by the primary ophthalmologist, was detected by gonioscopy, embedded in the anterior chamber angle. It was successfully surgically removed and visual results were good.

DISCUSSION

In any patient with unilateral unexplained corneal edema, it is necessary to rule out the presence of a foreign body in the anterior chamber.

Gene-specific promoter methylation is associated with micronuclei frequency in urothelial cells from individuals exposed to organic solvents and paints

Sufficient epidemiologic evidence has established an etiologic link between bladder cancer risk and occupational exposure as a painter to organic solvents. Currently, it remains to be established whether gene-specific promoter methylation contributes to bladder cancer development, including by enhancing chromosome breakage or loss. We investigated the effect of chronic exposure to organic solvents and paints on DNA methylation profiles in the promoter regions of four genes (GSTP1, p16(INK4a), APC and CDH1) and micronucleus (MN) frequency in exfoliated urothelial cells from voided urine from Colombian male non-smoking car painters and age-matched unexposed individuals. The exposed group had a higher percentage of individuals with >2 MNs/2000 cells compared with the unexposed group (P=0.04). Gene-specific analysis showed a significantly higher percentage of individuals with methylated GSTP1, p16(INK4a) and APC in the exposed group. Poisson regression analysis indicated that exposed individuals with methylated GSTP1 and p16(INK4a) promoters were more than twofold more likely to have an increase in MN frequency as compared with the reference. Finally, among exposed individuals with GSTP1 and p16(INK4a) methylated promoters, those with a greater age had a higher RR of increased MN frequency compared with younger exposed individuals with methylated promoters. These results support the conclusion that gene-specific promoter methylation may increase MN frequency in a dependent or independent interaction with occupational exposure to organic solvents.

Keratoconus: an inflammatory disorder?

Keratoconus has been classically defined as a progressive, non-inflammatory condition, which produces a thinning and steepening of the cornea. Its pathophysiological mechanisms have been investigated for a long time. Both genetic and environmental factors have been associated with the disease. Recent studies have shown a significant role of proteolytic enzymes, cytokines, and free radicals; therefore, although keratoconus does not meet all the classic criteria for an inflammatory disease, the lack of inflammation has been questioned. The majority of studies in the tears of patients with keratoconus have found increased levels of interleukin-6 (IL-6), tumor necrosis factor-α(TNF-α), and matrix metalloproteinase (MMP)-9. Eye rubbing, a proven risk factor for keratoconus, has been also shown recently to increase the tear levels of MMP-13, IL-6, and TNF-α. In the tear fluid of patients with ocular rosacea, IL-1α and MMP-9 have been reported to be significantly elevated, and cases of inferior corneal thinning, resembling keratoconus, have been reported. We performed a literature review of published biochemical changes in keratoconus that would support that this could be, at least in part, an inflammatory condition.

[In vitro antibiotic susceptibility to fluoroquinolones]

OBJECTIVE

To determine the antibiotic susceptibility of bacteria recovered from cultures of ocular infections in the Fundación Oftalmológica de Santander - Clínica Carlos Ardila Lulle (FOSCAL).

MATERIALS AND METHODS

Retrospective descriptive study of a series of registries of cultures of samples from ocular surfaces and intraocular fluids from the OCULAB-FOSCAL laboratory in Floridablanca (Colombia) made between January and December of 2007. Antibiotic sensitivity screening by the method of Kirby-Bauer with impregnated Sensi-Discs™ of determined antibiotic concentrations was performed.

RESULTS

A total of 352 samples were studied: 160 from conjunctiva, 150 from cornea and 42 from intraocular fluids. Of the total of the samples more than one microorganism was recovered 45.65% of the samples. Gram positive and Gram negative bacteria were identified in 78.7 and 18.4%, respectively. Resistance to gatifloxacin, moxifloxacin, ciprofloxacin and levofloxacin was observed in 6.3, 8.9, 33.2 and 35.6%, respectively, of Gram positive bacteria. Resistance to gatifloxacin, moxifloxacin, ciprofloxacin and levofloxacin was also observed in 7.4, 16.7, 16.7%and 25.9%, respectively, of Gram negative bacteria. The overall bacterial resistance (Gram positive and Gram negative) to moxifloxacin was 10.15%, and to gatifloxacin it was 6.46%, being which showed a statistically significant difference (P<.05).

CONCLUSIONS

In our study the development of bacterial resistance to fourth generation fluoroquinolones was demonstrated in ocular samples. However, lower levels of resistance to fourth generation fluoroquinolones compared with that of third and second generation were found, particularly to Gram positive. Gatifloxacin showed lower resistance levels than moxifloxacin. Nevertheless, interpretation of this superiority must be made with caution in the clinical field, since other factors, like tissue penetration and in vivo activity, must be taken into account.

Amygdalar hyperactivity, a fear-related link between panic disorder and mesiotemporal epilepsy

The sudden onset, short duration and stereotyped features of panic attacks, and the fear aura of seizures starting at the mesial aspects of the temporal lobe, suggest common mechanisms underlying panic disorder (PD) and mesiotemporal epilepsy (MTLE). However, current consensus emphasizes the importance of differentiating the two entities based on 1) intact consciousness in panic attacks, 2) poor response to antiepileptics, and 3) unsuccessful electrophysiological attempts to demonstrate a relationship. We report two cases with a diagnosis of PD that had been partially responsive to first line treatments. During the EEG session, both patients developed panic symptoms with minimal EEG changes in response to paper bag-hyperventilation (PB-HV), and several minutes later presented a clear ictal EEG pattern associated with very different clinical symptoms, but both with strong fear content. Z-scored LORETA analysis showed increased current source densities (CSD) at the right amygdala in both subjects during the induced panic symptoms. Several areas were involved during the seizure, different in each subject. Yet, a very significant increase at the amygdala was found in both cases. The LORETA Z-scored source correlation (LSC) analysis also showed similar abnormal patterns during the panic symptoms in both patients, and marked differences during the seizure. These findings show a major role of amygdalar hyperactivity in both fear-related conditions for the two patients, and are discussed in relation to existing models of PD in general. Abnormal overactivation at mesiotemporal regions is poorly represented at the surface recordings but can be detected by the appropriate analytical techniques.

How do land-based salmonid farms affect stream ecology?

Increasing research is highlighting the fact that streams provide crucial ecosystem services through the biogeochemical and ecological processes they sustain. Freshwater land-based salmonid farms commonly discharge their effluents into low order, headwater streams, partly due to the fact that adequate freshwater resources for production are commonly found in undisturbed areas. We review the effects of salmonid farm effluents on different biological components of stream ecosystems. Relevant considerations related to the temporal and spatial scales of effluent discharge and ecological effects are discussed. These highlight the need to characterize the patterns of stressor discharge when assessing environmental impacts and designing ecological effects studies. The potential role of multiple stressors in disrupting ecosystem structure and function is discussed with an emphasis on aquaculture veterinary medicines. Further research on the effects of veterinary medicines using relevant exposure scenarios would significantly contribute to our understanding of their impact in relation to other effluent stressors.

The performance of three serum creatinine-based formulas in estimating GFR in former kidney donors

Studies addressing long-term consequences of living with one kidney have used serum creatinine-based formulas that have not been validated in former kidney donors. Therefore, we evaluated the performance of Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD) and Mayo Clinic formulas in predicting iohexol glomerular filtration rate (iGFR) after donation in 112 randomly selected former kidney donors. Mean time from donation was 12.2 +/- 8.5 years. Serum creatinine was 1.1 +/- 0.2 mg/dL and iohexol GFR was 72 +/- 12 mL/min/1.73 m(2). The majority, 83.9%, of donors had a GFR >60 mL/min. CG formula overestimated GFR by 3.35 +/- 13.6 mL/min and was within 10% of iohexol GFR in only 43.7% of cases. MDRD formula underestimated iohexol GFR by 6.45 +/- 9.5 mL/min and was within 10% of actual GFR in half of the cases. In contrast, the Mayo Clinic equation was the most biased at 14.71 +/- 12.3 mL/min and was within 10% of measured GFR in only a fifth of the cases. Only MDRD and CG formulas provide estimates of GFR in former kidney donors that are within a clinically acceptable range of actual GFR. In conclusion, the majority of former kidney donors have excellent kidney function and the MDRD formula should be the recommended GFR estimating model in this population.

Sinovitis crónica hipertrófica vellosa de la vaina del tendón flexor tras picadura de abeja

Presentamos un caso inusual de sinovitis deformante del tendón flexor en una mujer de 18 años de edad, con el antecedente de una picadura de abeja 12 meses antes de su consulta. En su historia destaca un cuadro de dolor y edematización progresivos, con bloqueo de la flexión y de la extensión del tercer dedo de la mano derecha. Durante la intervención quirúrgica se disecó una gran masa de tejido blando, destruyendo el sistema de poleas entre la A1 y la A4. Se practicó extensa sinovectomía y reconstrucción de las poleas. El estudio histopatológico reveló una sinovitis crónica hipertrófica con hiperplasia vellosa y granulomas.

A prospective study of the clarithromycin-digoxin interaction in elderly patients

The study was a prospective observational trial carried out to assess the clarithromycin-digoxin interaction in elderly patients chronically taking digoxin. Digoxin concentrations were determined before and after concomitant treatment with clarithromycin. A Bayesian approach was used to calculate digoxin pharmacokinetics. In the seven patients who were studied there was a significant increase in digoxin concentration after 4-7 days of clarithromycin treatment; digoxin clearance and elimination rate constant were 56-60% lower and elimination half-life was 82% longer. The pharmacokinetic clarithromycin-digoxin interaction in the elderly may be much more frequent than has been assumed up to now.

Unraveling the realities of vascular access: the Network 11 experience

Arteriovenous (AV) fistulae are well recognized as the preferred vascular access for hemodialysis, yet national data show that only 23% of patients used an AV fistula in 1997. To identify barriers to the placement of native AV fistulae, the Renal Network of the Upper Midwest, Inc. (End-Stage Renal Disease [ESRD] Network 11) initiated a vascular access project to look at the process of referral for patients beginning hemodialysis in the first 6 months of 1999. Of these patients, 63% began hemodialysis with a catheter as the only access, 22% had an AV fistula placed (but only 14% used an AV fistula for their first dialysis treatment), and 15% began with a graft. About 40% of patients were referred to a nephrologist less than 1 month before dialysis, allowing little chance for permanent access placement. Yet 27% of patients used a catheter on the first hemodialysis treatment and were seen by a nephrologist more than 1 month before starting dialysis, indicating the presence of an opportunity to improve. At 6 months after initiation of dialysis, 25% of patients who began dialysis using a catheter were using an AV fistula and 35% were using a graft. Network 11 plans to use this information to promote early referral of patients to a nephrologist and subsequent prompt referral of such patients to a vascular surgeon. Other activities to improve vascular access management are also indicated.

[Guidelines of the Spanish Society of Cardiology on valve heart disease]

Valvular heart diseases, which continue to be a major cause of morbidity and mortality world wide, have undergone radical changes since the first valve prostheses were implanted 40 years ago. These changes have been the result of both scientific progress and improved standard of living in developed countries. The availability of penicillin to treat streptococcal pharyngitis and less crowded living conditions have now made rheumatic fever uncommon in these countries. However, other forms of valve impairment have appeared over the past several years. The etiology of some of these valvular diseases remains obscure (e. g. myxomatous mitral valve); others, such as the senile type of calcific aortic valve stenosis, seem to be the price to be paid for the extension of life expectancy. With regard to diagnosis, echocardiography has constituted a formidable tool for visualizing anatomic valve changes, interpreting complex hemodynamic derangements, and evaluating repercussion on the left ventricle. In addition, the iteration of this non-invasive examination has allowed a much better understanding of the natural history of non-severe valvular disease and therefore of the precise timing for surgical intervention, without awaiting, in most cases, the appearance of advanced symptomatology. This has also been possible because of the great advances in cardiac surgery which can be summarised as: a) the improvement in extracorporeal circulation and myocardial preservation techniques; b) the greatly improved biologic and mechanic valve substitutes; c) the introduction of imaginative mitral valve repair procedures, and d) the use of intraoperative transesophageal echocardiography to assess the adequacy of valve repair. At the same time, percutaneous catheter balloon valvuloplasty has emerged as a valid alternative to mitral surgical commissurotomy for mitral stenosis. All these changes, and many more that can not be described in this brief summary, make a review of the management of patients with valve heart disease appropriate.

Asymmetries in brain maturation and behavioral disturbances: multivariate electroencephalogram and P300 studies

If behavior results from brain function, some evidence of dysfunction could be expected in children with major behavioral problems. Yet, neurophysiologic studies in these children are frequently normal. We hypothesized a relationship between maturational asymmetry and behavior, given the role of hemispheric imbalance in adult psychopathology. The purpose of this study was to investigate whether age-sensitive neurophysiologic measures could identify behaviorally relevant maturational asymmetries in otherwise healthy children. Ninety-five children were studied; reasons for testing were behavioral (19), academic (12), medical nonneurologic (16), and mixed (28), along with 20 control subjects. Academic, behavioral (Child Behavioral Checklist), and psychometric (Wechsler Intelligence Scale for Children-Revised; WISC-R) measures were analyzed in relation to four neurophysiologic parameters: P300 Latency, P300 Latency Asymmetry, Maturational Z-score, and Maturational Z-score Asymmetry, within a canonical design. The highest correlation was behavior with Maturational Z-score Asymmetry. Academic scores were predicted by the three-variable interaction of P300 Latency,Maturational Z-score, and Maturational Z-score Asymmetry. We concluded that behavior was strongly influenced by maturational asymmetry, while academic performance depended on both global maturation and maturational asymmetry. Our results suggest that behavioral disturbances can have a neural substrate despite apparently normal electroencephalograms (EEGs) and event-related potentials (ERPs). They open the possibility for specific therapeutic interventions to improve behavior and performance, and, perhaps, prevent major psychopathology in later life.

A patient with Simpson-Golabi-Behmel syndrome and hepatocellular carcinoma

Simpson-Golabi-Behmel syndrome (SGBS) is an X linked disorder characterised by pre- and postnatal overgrowth, coarse facial features, and visceral and skeletal abnormalities. Like other overgrowth syndromes, in the SGBS there is an increased risk for developing neoplasia, mainly embryonic, such as Wilms tumour. We report a 3 year old male patient with SGBS and hepatocellular carcinoma, a previously undescribed tumour associated with the syndrome.

Selected quantitative EEG (QEEG) and event-related potential (ERP) variables as discriminators for positive and negative schizophrenia

Heterogeneity is a major obstacle in the search for biological substrates in schizophrenia. The positive and negative distinction, even if too simplistic, may improve our understanding of underlying processes. Frontostriatal deficits have been related to negative symptoms, while dysfunction of the dominant temporal lobe appears more relevant to the generation of positive symptoms. Despite interactions between the subsystems, different neurophysiological profiles could be expected for patients predominantly affected at each of those levels. We performed discriminant analysis on 10 neurophysiological variables (hypothesis-related) in schizophrenic patients grouped by positive or negative symptoms (PANSS), obtaining a discriminant that correctly classified the sample. The function was then tested in a new sample of patients with schizophrenia, affective psychoses, and controls, classifying subjects with 78% sensitivity and 85% specificity. Our findings suggest that predominantly negative and positive schizophrenics have different neurophysiological profiles, which are consistent with the hypotheses of hypofrontality and temporal lobe dysfunction, respectively. A linear relation between discriminant scores and PANSS ratings might reflect coexisting pathologies or compensatory interactions in the mixed subgroup.

External carotid artery fistula due to microcompression of the gasserian ganglion for relief of trigeminal neuralgia. Case report

Vascular complications after percutaneous injection procedures for relief of trigeminal neuralgia are varied, ranging from puncture of arterial or venous structures to carotid-cavernous fistulas. The authors present a patient in whom an external carotid artery fistula occurred after a microcompression procedure for the treatment of a left-sided trigeminal neuralgia. This is believed to be the first case of this complication secondary to a percutaneous injection procedure for relief of facial pain.