A fluorophotometric comparison of anterior chamber riboflavin delivery via corneal application and fornix instillation

INTRODUCTION AND OBJECTIVES

We investigated whether riboflavin self-administration by patients could be a feasible option for corneal cross-linking, given the considerable resources required to impregnate the cornea with riboflavin. We analysed whether administering riboflavin in the inferior fornix (the site of self-administration) results in non-inferior riboflavin concentrations as when applied directly on the cornea (the site of administration by medical personnel).

PATIENTS AND METHODS

We conducted a prospective study to evaluate riboflavin concentrations at six time-points (baseline, 5, 15, 30, 45 and 60min) in 18 healthy volunteers for each of two application sites: cornea and fornix. Anterior chamber riboflavin (Peschke® TE 0.25%) concentrations were measured by fluorophotometry (Fluorotron™ Master FM-2).

RESULTS

For the two application sites cornea and fornix, participants did not differ in terms of age and sex. At baseline, the autofluorescence in the anterior chamber was 16.7ng/mL (SD 5.5) and 14.6ng/mL (SD 4.6) (P=.221). After 30min, anterior chamber fluorescein concentrations had risen to 55.1ng/mL (SD 25.5) and 46.1ng/mL (SD 25.1) (P=.293) without a further relevant increase by 60min.

CONCLUSIONS

This study found that applying riboflavin drops in the inferior fornix was non-inferior to applying it directly to the cornea, based on fluorophotometric measurements of anterior chamber riboflavin concentrations. This suggests that self-application of riboflavin is feasible in terms of corneal riboflavin impregnation.

Economic Evaluation of an Intervention to Prevent Adolescent Dating Violence (Me & You)

Me & You: Building Healthy Relationships (Me & You) is a multilevel, technology-enhanced adolescent dating violence (DV) prevention program that aimed to reduce DV among ethnic-minority, early adolescent, urban youth. A group-randomized control trial of Me & You, conducted with 10 middle schools from a large urban school district in Southeast Texas in 2014-2015, found it to be effective in reducing DV perpetration and decreasing some forms of DV victimization. Economic evaluations of DV interventions are extremely limited, despite calls for more economic analyses to be incorporated in research. We help fill this gap by evaluating the cost-effectiveness from the payer and societal perspectives of implementing the Me & You program. Using cost data collected alongside the Me & You group-randomized trial, we computed incremental cost-effectiveness ratios. Our primary outcome was "any DV perpetrated" within 12 months of the intervention. We conducted a cost-benefit analysis beyond the intervention endpoint by using literature estimates of per-victim lifetime costs of DV. We performed sensitivity analyses to assess effects of uncertain parameters. Under the base-case scenario, the cost of the Me & You curriculum compared to the standard curriculum was $103.70 per-student from the societal perspective, and the effectiveness was 34.84 perpetrations averted, implying an incremental cost per perpetration averted of $2.98, which ranged from $0.48 to $73.24 in sensitivity analysis. Thus, we find the Me & You curriculum is cost-effective and cost-saving in most scenarios. Policymakers should carefully consider school-based DV prevention programs, and cost data should be regularly collected in adolescent prevention program evaluations.

Socio-Ecological Factors Associated With Students' Perceived Impact of an Evidence-Based Sexual Health Education Curriculum

BACKGROUND

Although schools often implement evidence-based sexual health education programs to address sexual and reproductive health disparities, multiple factors may influence program effectiveness.

METHODS

Using student-reported perceived impact measures as a proxy for program effectiveness, we employed a socio-ecological approach to examine student, teacher, school, and district factors associated with greater perceived impact of It's Your Game (IYG), an evidence-based middle school sexual health education program. The student sample was 58.7% female, 51.8% Hispanic, mean age 13.2 years, from 73 middle schools. We assessed students' (N = 4531) perceived impact of IYG on healthy decision-making (α = 0.75) and sexual communication (α = 0.71); satisfaction with IYG activities and teacher; and demographics. We assessed teachers' (N = 56) self-efficacy to teach IYG, perceived administrative support, implementation barriers, and demographics. School and district data were abstracted from state records. We used multilevel logistic regression to estimate associations between independent variables and student-reported perceived impact.

RESULTS

In final multivariate models, students' demographics (sex, β = 0.06, SE = 0.015), satisfaction with IYG (β = 0.21, SE = 0.012), and their IYG teacher (β = 0.18, SE = 0.013) (all p = .000) were significantly associated with perceived impact on healthy decision-making. Similar findings resulted for sexual communication. No other variables were significantly associated with perceived impact.

CONCLUSIONS

Helping schools select age-appropriate, culturally relevant programs, and facilitate supportive learning environments may enhance the perceived impact of sexual health education programs.

Replication of It's Your Game…Keep It Real! in Southeast Texas

Despite the recent efforts of the Office of Adolescent Health to replicate programs with demonstrated efficacy, there are still few evidence-based HIV, sexually transmitted infection (STI), and teen pregnancy prevention programs that have been replicated in "real-world" settings. To test the effectiveness of It's Your Game…Keep It Real! (IYG), an evidence-based STI and pregnancy prevention program for middle schools, the curriculum was implemented by teachers in urban and suburban middle schools in Southeast Texas from 2012 to 2015. IYG was evaluated using a group-randomized wait-list controlled effectiveness trial design in which 20 middle schools in nine urban and suburban school districts in Southeast Texas were randomized equally, using a multi-attribute randomization protocol, to either the intervention condition (received IYG) (n = 10 schools comprising 1936 eligible seventh graders) or the comparison condition (received usual care) (n = 10 schools comprising 1825 eligible seventh graders). All students were blinded to condition prior to administering the baseline survey. The analytic sample comprised 1543 students (n = 804, intervention; n = 739, comparison) who were followed from baseline (seventh grade) to the 24-month follow-up (ninth grade). Multilevel regression analyses were conducted to assess behavioral and psychosocial outcomes at follow-up. There were no significant differences in initiation of vaginal or oral sex between study conditions at follow-up. However, at 12-month follow-up, compared with students in the comparison condition, students in the intervention condition reported increased knowledge, self-efficacy, and perceived favorable norms related to HIV/STIs, condoms, and/or abstinence; decreased intentions to have sex; and increased intentions to use birth control. Knowledge outcomes were statistically significant at 24-month follow-up. This IYG effectiveness trial did not replicate the behavioral effects of the original IYG efficacy trials. However, it adds to the growing literature on the replication of evidence-based programs, and underscores the need to better understand how variations in implementation, setting, and measurement affect the behavioral impact of such programs.Clinical trial registration clinicaltrials.gov (NCT03533192).

Adolescent Dating Violence Prevention Program for Early Adolescents: The Me & You Randomized Controlled Trial, 2014-2015

Objectives. To test the efficacy of Me & You, a multilevel technology-enhanced adolescent dating violence (DV) intervention, in reducing DV perpetration and victimization among ethnic-minority early adolescent youths. We assessed secondary impact for specific DV types and psychosocial outcomes.Methods. We conducted a group-randomized controlled trial of 10 middle schools from a large urban school district in Southeast Texas in 2014 to 2015. We used multilevel regression modeling; the final analytic sample comprised 709 sixth-grade students followed for 1 year.Results. Among the total sample, odds of DV perpetration were lower among intervention students than among control students (adjusted odds ratio = 0.46; 95% confidence interval = 0.28, 0.74). Odds of DV victimization were not significantly different. There were significant effects on some specific DV types.Conclusions. Me & You is effective in reducing DV perpetration and decreasing some forms of DV victimization in early middle-school ethnic-minority students.

[Complications of Descemet Stripping Automated Endothelial Keratoplasty (DSAEK)]

BACKGROUND

Lamellar keratoplasties, e.g. Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) are considered the procedures of choice for corneal endothelial diseases. In comparison to penetrating keratoplasty (PK) they are associated with faster visual rehabilitation, a lower risk of complications and a decreased necessity for follow-up visits, which reduces the burden on quality of life in elderly patients. In order to advise patients regarding the indications for surgery and to facilitate the follow-up management, it is important to know the most important complications associated with these keratoplasty techniques.

RESULTS AND DISCUSSION

The most important preoperative complication is a delayed indication for the operation. In contrast to PK, DSAEK and DMEK surgery should be provided at an earlier stage of disease as chronic edema alters the stroma and reduces the speed of visual recovery. The most important complications during or early after surgery are detached lamellae, pupillary blocks with increased pressure or air bubbles in the vitreous cavity in patients with previous vitrectomy. The main long-term complications include chronic increased intraocular pressure and immune-mediated graft rejections in DSAEK patients after reducing or stopping topical corticosteroid therapy. This article describes the potential complications of endothelial keratoplasty and provides a detailed explanation of strategies to avoid these complications.

Blood flow velocity measured using the Retinal Function Imager predicts successful ranibizumab treatment in neovascular age-related macular degeneration: early prospective cohort study

PURPOSE

Anti-VEGF treatment has a potent vasoconstrictive effect. Early changes of retinal blood flow velocity (RBFV) measured using the Retinal Function Imager (RFI) combined with indicators of vascular status may help in predicting the visual outcome 1 month post injection in patients with neovascular age-related macular degeneration (nvAMD) under ranibizumab treatment. To develop a simple prediction model based on the change in RBFV 3 days post injection and indicators of a patient's vascular status to assess the probability of a successful visual outcome 1 month post injection.

METHODS

RBFV measured using RFI were prospectively collected pre-injection and 3 days post injection in 18 eyes of 15 patients. Indicators of vascular status (history of hypertension, diabetes mellitus without retinal affection, and smoking) were assessed by medical history. By univariate analyses, parameters associated with visual outcome were weighted (-1 to 6 points). A multivariate logistic regression model with the categorized visual outcome parameter (≥0 letters gained after 1 month) as the dependent variate and the sum score as the independent variate (continuous scale) was used to estimate the score value-specific probabilities of letters gained ≥0 1 month post injection.

RESULTS

The indicators of vascular status negatively influenced the likelihood of a letter gain ≥0 whereas an increase in the arterial RBFV strongly increased it. The area under the receiver operating characteristics curve for these parameters investigated was 0.71 (95% CI: 0.43-1.00).

CONCLUSION

Changes in the arterial RBFV following 3 days after ranibizumab injection combined with three indicators of the vascular status identified nvAMD patients with favorable visual outcome accurately.

Diagnostic accuracy of the Amsler grid and the preferential hyperacuity perimetry in the screening of patients with age-related macular degeneration: systematic review and meta-analysis

OBJECTIVE

To clarify the screening potential of the Amsler grid and preferential hyperacuity perimetry (PHP) in detecting or ruling out wet age-related macular degeneration (AMD).

EVIDENCE ACQUISITION

Medline, Scopus and Web of Science (by citation of reference) were searched. Checking of reference lists of review articles and of included articles complemented electronic searches. Papers were selected, assessed, and extracted in duplicate.

EVIDENCE SYNTHESIS

Systematic review and meta-analysis. Twelve included studies enrolled 903 patients and allowed constructing 27 two-by-two tables. Twelve tables reported on the Amsler grid and its modifications, twelve tables reported on the PHP, one table assessed the MCPT and two tables assessed the M-charts. All but two studies had a case-control design. The pooled sensitivity of studies assessing the Amsler grid was 0.78 (95% confidence intervals; 0.64-0.87), and the pooled specificity was 0.97 (95% confidence intervals; 0.91-0.99). The corresponding positive and negative likelihood ratios were 23.1 (95% confidence intervals; 8.4-64.0) and 0.23 (95% confidence intervals; 0.14-0.39), respectively. The pooled sensitivity of studies assessing the PHP was 0.85 (95% confidence intervals; 0.80-0.89), and specificity was 0.87 (95% confidence intervals; 0.82-0.91). The corresponding positive and negative likelihood ratios were 6.7 (95% confidence intervals; 4.6-9.8) and 0.17 (95% confidence intervals; 0.13-0.23). No pooling was possible for MCPT and M-charts.

CONCLUSION

Results from small preliminary studies show promising test performance characteristics both for the Amsler grid and PHP to rule out wet AMD in the screening setting. To what extent these findings can be transferred to a real clinic practice still needs to be established.

Effects and adverse events after CXL for keratoconus are independent of age: a 1-year follow-up study

PURPOSE

To compare the effect, failure rate and the risks of corneal cross-linking (CXL) in keratoconus patients aged ≥35 years to patients <35 years.

METHODS

In 141 eyes of 116 keratoconus patients we compared the changes in best phoropter-corrected visual acuity (BCVA) and maximum keratometry values (Kmax) before and 12 months after CLX in patients aged ≥35 years (n=34, 38 eyes) to the cohort of patients below 35 years of age.

RESULTS

Overall, CXL significantly improved BCVA from 0.487 logMAR (95% confidence interval (CI) 0.426-0.548) by -0.197 logMAR (95% CI -0.243 to -0.150; P<0.001) and reduced Kmax from 48.96 diopter (Dpt) by -1.33 Dpt (95% CI -1.85 to -0.81: P<0.001). Age ≥35 years had no effect on the changes of BCVA (-0.02 (95% CI -0.13 to 0.09); P=0.757) or Kmax (0.58 (95%CI -0.51 to 1.68); P=0.294) as compared with younger patients. In 54 patients (55 eyes, 38.5%) aged <35 years and in 18 patients (18 eyes, 47.4%) aged ≥35 years, BCVA increased by ≥2 Snellen lines. Failure (increase in Kmax ≥1 Dpt) was observed in 17 eyes (16.5%) of patients aged <35 years and in 3 eyes (7.9%) of patients aged ≥35 years during the 12-month follow-up period. Adverse outcomes (loss of ≥2 Snellen lines) occurred in 4 (3.9%) eyes of patients aged <35 years and 1 (2.6%) eye of a patient aged ≥35 years.

CONCLUSION

Effects and adverse events of CXL treatment do not seem to differ between subjects younger or older than 35 years.

Central corneal regularization--optimization of uncorrected visual acuity in keratoconus patients

BACKGROUND

Combined excimer laser correction and corneal cross-linking is a promising concept in treating keratoconus patients. Central corneal regularization represents advanced topography-guided custom ablation for ectatic corneas, aiming at correcting irregular astigmatism and at increasing the optical regularity of the corneal surface.

PATIENTS AND METHODS

In a prospective single centre study, 10 keratoconus patients underwent combined treatment with corneal cross-linking and central corneal regularization by an iRES-Laser. Uncorrected visual acuity at 1 and 3 months postoperatively represented the primary endpoint.

RESULTS

Mean preoperative uncorrected decimal visual acuity was 0.15 (± 0.28 standard deviation). Mean postoperative visual acuity was 0.28 (± 0.47) at one month and 0.24 (± 0.25) at three months, respectively.

CONCLUSIONS

Combined corneal cross-linking and central corneal regularization treatment has the potential to achieve a clinically significant improvement of uncorrected visual acuity.

Corneal cross-linking as supplementary treatment option in melting keratitis: a case series

BACKGROUND

Corneal melting represents a serious condition that can result in corneal perforation and loss of vision. Treatment options include topical and systemic immunosuppression, cyanoacrylate gluing, and emergency keratoplasty, depending on the underlying disease and the stage of corneal melt. Recently, corneal cross-linking (CXL) has emerged as an additional treatment option. The present study evaluates whether CXL induces a clinical improvement in melting keratitis not responding to conventional treatment.

HISTORY AND SIGNS

Six patients undergoing CXL for corneal melting of variable origin (including bacterial, fungal and Acanthamoeba keratitis) were reviewed retrospectively.

THERAPY AND OUTCOME

Treatment parameters included riboflavin application following UV irradiation with a wavelength of 370 nm and an irradiance of 3 mW/cm2 for 30 minutes. Four patients with corneal melting due to contact lens-related infectious keratitis showed healing without any need for further interventions up to date. In two patients, CXL stabilized the melting cornea and facilitated additional surgical procedures.

CONCLUSIONS

By stabilizing corneal collagen fibres, CXL seems to represent an effective option to re-establish corneal integrity in the event of pending perforations. In established perforations, CXL facilitates further emergency procedures by stiffening the tissue.

[Cataract surgery - essentials for the general practitioner]

Age-related cataracts are mainly caused by life-long accumulation of oxidative stress on the lens fibres. Symptoms include reduced visual acuity, requiring more light for reading, and glare. The only treatment that provides a cure for cataracts is surgery. Phacoemulsification represents the preferred method of lens removal. It involves fragmentation of the lens using ultrasound and insertion of an artificial intraocular lens. The preoperative assessment the general practitioner provides to surgeon and anesthesia team has an important share in the low complication rate of the procedure in the event of co-existing systemic disease. Growing patient expectation for spectacle independence following cataract surgery is met to some extent using techniques for astigmatism control and presbyo-pia-correcting intraocular lenses.

The disc damage likelihood scale (DDLS): interobserver agreement of a new grading system to assess glaucomatous optic disc damage

BACKGROUND

The disc damage likelihood scale (DDLS) is a new grading system to estimate the amount of optic disc damage in glaucoma patients. The objective of this study was to assess the interobserver agreement of the DDLS and the cup/disc ratio.

PATIENTS AND METHODS

The reproducibility of the DDLS and the cup/disc ratio was measured by two masked observers (one glaucoma specialist and one of two resident physicians in their first 6 months of training) staging 42 eyes of 25 patients with glaucoma or ocular hypertension. Disc size, cup/disc ratio and DDLS were documented and the Cohen's kappa was calculated as a measure for interobserver agreement.

RESULTS

The interobserver agreement for the cup/disc ratio was good (Cohen's kappa 0.803). For the DDLS, the interobserver agreement was even better (Cohen's kappa 0.902).

DISCUSSION

Unlike the cup/disc ratio, which focuses on the excavation, the DDLS is based directly on the thickness of the neuroretinal rim and takes into account the optic disc size. Therefore, the DDLS estimates the glaucomatous damage of the optic disc more precisely than the currently used method. Although this new grading system is more complicated to use in clinical practice, the interobserver agreement for the DDLS in our study setting was very good.

Contact lens-associated fusarium keratitis in Switzerland

BACKGROUND

Fusarium has been an exceptionally rare cause of infectious keratitis. A recent outbreak of Fusarium keratitis in contact lens wearers in North America and Asia has been associated with the multipurpose disinfection solution ReNu with MoistureLoc (Bausch&Lomb). We report a series of Fusarium keratitis in Swiss contact lens wearers.

PATIENTS AND METHODS

A multicentre retrospective case review of patients with corneal ulceration and a positive microbiological identification of Fusarium species was undertaken.

RESULTS

Between September 2005 and August 2007, six cases of Fusarium keratitis were identified. Patients were 39 to 63 years of age. All patients were using disposable soft contact lenses for at least two years. Four patients used daily wear disposable lenses. Two patients were wearing 1-monthly disposable lenses and used ReNu with MoistureLoc solution. Due to multiresistant Fusarium, enucleation was required in two cases and an emergency keratoplasty was performed in three cases. An optical keratoplasty was undertaken in one case that developed corneal scarring. Final visual acuity in patients with preserved eyes ranged from light perception to 8 / 20.

CONCLUSIONS

Exposure to ReNu with MoistureLoc is not the only risk factor for Fusarium keratitis. In addition to antifungal therapy, an early keratoplasty with excision of the infected tissue seems mandatory to improve prognosis.

Phosphate concentration in ophthalmic corticoid preparations

BACKGROUND

Topical preparations, high in phosphate, may cause calcification when used on a damaged corneal surface. The knowledge of the phosphate concentration in medications helps to prevent corneal calcifications. Our study gives an overview of the amount of phosphate contained in ophthalmic corticoid preparations.

METHODS

Samples of 38 commercially available corticoid preparations were tested. The quantification of phosphate was performed using the molybdate method on a Modular P autoanalyzer.

RESULTS

18 of 38 preparations (47%) had a phosphate concentration above physiological levels (>1.45 mmol/l). It varied greatly, and ranged from less than 0.1 mmol/l (18 preparations) to 62.6 mmol/l. The corticoids that were tested included betamethasone sodium phosphate (18.3-35.5 mmol/l), dexamethasone (0.1-17.6 mmol/l), dexamethasone sodium phosphate (<0.1-62.6 mmol/l), fluorometholone (<0.1-22.5 mmol/l), and prednisolone acetate (<0.1-0.5 mmol/l).

CONCLUSIONS

The phosphate concentration in corticoid-phosphate formulations varies greatly, and is mainly determined by the chosen buffer. The prednisolone acetate preparations showed physiological phosphate concentrations. For a treatment on a damaged corneal surface, preparations with physiological phosphate concentrations should be used.

Antibiotic Susceptibilities of Bacteria Isolated from Ophthalmic Specimens between 1984 and 2005 in Zurich, Switzerland

BACKGROUND

Increasing resistance of bacteria cultured from ophthalmic specimens to antibiotic therapy has been documented worldwide. Inappropriate prescribing practices are thought to represent a major risk factor for antibiotic resistance. This study investigates the pattern of bacterial antibiotic susceptibility in Zurich, Switzerland over a period of twenty years.

METHODS

Antibiotic susceptibilities of bacterial isolates from all ophthalmic specimens cultured at the Institute of Medical Microbiology in Zurich between 1984 and 2005 were analysed retrospectively.

RESULTS

A total of 7,862 ocular surface samples have been collected. 3,010 specimens (38.3 %) were positive for aerobic bacteria. The strains isolated most frequently were Staphylococcus aureus (23.9 %), coagulase-negative staphylococci (16.1 %), Pseudomonas aeruginosa (10.0 %), Haemophilus influenzae (6.3 %), Escherichia coli (5.1 %), Serratia marcescens (4.7 %), and Streptococcus pneumoniae (3.9 %). Various bacteria accounted for the remaining 30.0 %. Susceptibility of these strains to the aminoglycosides, quinolones, and cephalosporins tested did not change over this period of time.

CONCLUSION

The data suggest that bacteria cultured from ophthalmic specimens in Zurich, Switzerland have not changed their pattern of antibiotic susceptibility over the past 20 years.

Phosphate Concentrations in Antiglaucoma Medication

BACKGROUND

Eye drops may contain phosphates as part of their buffer system. In the presence of epithelial keratopathy a high concentration of phosphate favours corneal calcification. To date European legislation does not require a quantitative declaration of the phosphates since buffers are regarded as additives. The knowledge of the phosphate concentration in medications helps to prevent corneal calcifications. Our study gives an overview on the amount of phosphate contained in antiglaucoma drops.

METHODS

21 samples of commercially available antiglaucoma drops were tested. The quantification of phosphate was performed using the molybdate method on a Modular P autoanalyzer.

RESULTS

10 of 21 (47 %) glaucoma drops had a phosphate concentration above physiological levels (> 1.45 mmol/L). A concentration higher than 100 mmol/L was found in four preparations that contained timolol.

CONCLUSIONS

Many antiglaucoma drops contain unphysiological levels of phosphate, very high concentrations are found in some beta-blockers. These preparations have the potential to favour the formation of insoluble crystalline calcium phosphate deposits when used on a damaged corneal surface, and should therefore be avoided.

[Povidone-iodine for treatment of adenoviral conjunctivitis: an in vitro study]

BACKGROUND

Adenoviral conjunctivitis causes high socioeconomic costs due to high contagiousness and therefore the need for extended quarantine. To date the only potentially active, topical antiviral agent is povidone-iodine (PVI). The aim of this study was to investigate the effect of diluted PVI on free adenovirus and adenoviral infected cells as well as to evaluate the cellular toxicity of PVI on non-infected cells.

MATERIAL AND METHODS

PVI was diluted to a final concentration of 0.0008 %. Virucidal activity was measured IN VITRO using adenovirus 8 and A549 human epithelial cell cultures. Cytotoxicity effects on healthy cells after short- and long-term exposure to diluted PVI were measured in A549 cell cultures.

RESULTS

Exposure to PVI at a concentration of 1:10 (0.8 %) completely extinguishes infectivity of free adenovirus after an exposure time of 10 minutes. PVI is less effective against intracellular adenovirus resulting in a decreased infectivity and viral activity for approximately one day with a narrow spectrum between toxicity and virucidal activity. Healthy epithelial cells can be exposed to PVI for up to 6 hours without a cytotoxic effect.

CONCLUSIONS

PVI is highly effective against free adenovirus but less effective against intracellular adenoviral particles in already infected cell. Short- and long-term exposure of PVI causes little cytotoxicity for healthy cells. Therefore, administration of diluted PVI at a concentration of 1:10 is a potential option to reduce contagiousness in cases of adenoviral infections.

[Corneal and conjunctival findings in systemic silver intoxication]

BACKGROUND

Chronic silver intoxication is a rare disease and therefore the typical ocular findings may be missed. Based on a case with severe intoxication, the clinical and histological findings as well as the prognosis in argyria are presented.

HISTORY

A 33-years-old-employee of a battery production plant developed a biopsy proven systemic argyria. On slit lamp examination the conjunctiva showed a dark, blue-grey discoloration in the areas of the tear flow and the small conjunctival arteries. Diffuse silver deposits were noticed on the level of Descemet's membrane without endothelial damage. Silver deposits were also visible in the trabecular meshwork. Chemical reaction of the silver particles upon exposure to UV light results in irreversible tissue discoloration. Without options for an effective treatment, early diagnosis and prevention of overexposure are most important.

CONCLUSIONS

The typical ocular findings in systemic argyria are helpful in occupational medicine for establishing the correct diagnosis.

Bakterielles Kontaminationsrisiko nach Povidon-Iod-Desinfektion in der Kataraktchirurgie

BACKGROUND

Povidone-iodine alone or in combination with antibiotics is commonly used for presurgical disinfection in cataract surgery. In spite of the use of the combination Povidone-iodine and ofloxacin, the rate of ocular contamination as assessed from surgical knives was reported to be as high as 26 %. The aim of this study was to investigate the efficacy of diluted Povidone-iodine alone for surgical disinfection.

PATIENTS AND METHODS

126 consecutive patients undergoing elective cataract surgery with a conjunctival wound and a scleral tunnel received prior to surgery a disinfection with diluted Povidone-iodine eye drops (Braunol 1:10 diluted = 0.8 % Povidone-iodine, 3 times every 5 min). To assess residual bacteria on the ocular surface after disinfection, the surgical knives for the side ports and the scleral tunnel were cultured in thioglycolate broth.

RESULTS

In 8 out of 126 (6 %) patients the culture from the surgical knives revealed a positive result (89 % coagulase negative Staphylococci). Four of these 8 cases occurred during a single list. All control cultures remained negative.

CONCLUSION

Diluted Povidone-iodine eye drops alone are highly effective for bacterial disinfection when applied properly. The rate of contamination using 0.8 % Povidone-iodine in our series was considerably lower as compared to that of other studies.

Corneal calcification following intensified treatment with sodium hyaluronate artificial tears

AIM

To report a potential adverse effect of intensified treatment with sodium hyaluronate artificial tears.

METHODS

Five cases of deep calcium deposition in the cornea associated with ocular surface disease and frequent use of hyaluronic acid artificial tears are described. All patients used one formulation of phosphate buffered hyaluronate eye drops when rapid calcification developed. All eyes required corneal graft surgery for visual rehabilitation. Specimens at keratoplasty were available for light microscopy and investigation by dispersive x ray analysis. The phosphate concentration in the medication used for topical treatment was measured and compared to alternative hyaluronate preparations.

RESULTS

Light microscopy showed dense mineralisation of the entire stroma. The crystalline deposits consisted of hydroxyapatite, Ca5(PO4)3OH. A 50-fold higher concentration of phosphate was measured in the sodium hyaluronate eye drops used for treatment (50.9 mmol/l) when compared with normal serum. The other hyaluronate formulations showed phosphate concentrations from <0.1 mmol/l to 10.9 mmol/l.

CONCLUSIONS

The hyaluronate artificial tear formulation "Hylo-Comod" favours the formation of insoluble crystalline calcium phosphate deposits in presence of epithelial keratopathy. This is because of its high phosphate concentration and typically frequent instillation. Manufacturers and prescribers should be aware that topical preparations may contain considerable amounts of phosphate which may lead to sight threatening corneal complications.

Phosphate concentration in artificial tears

BACKGROUND

Irrigating solutions and eye drops may contain phosphates as part of their buffer system. In the presence of epithelial keratopathy, a high concentration of phosphate favours corneal calcification. Knowledge of the phosphate concentration in artificial tear products helps to prevent this sight-threatening complication. This study gives an overview on the amount of phosphate contained in artificial tears.

METHODS

Fifty-nine samples of commercially available artificial tear preparations were tested. The quantification of phosphate was performed using the molybdate method on a Modular P autoanalyzer.

RESULTS

Twenty-six of 59 (44%) artificial tear products had a phosphate concentration above physiological levels (>1.45 mmol/l). A phosphate concentration above 25 mmol/l was found in nine products (15%), a concentration higher than 50 mmol/l in three (5%).

CONCLUSIONS

Many artificial tear formulations contain unphysiological levels of phosphate, but very high concentrations are found only in a few products. These preparations have the potential to favour the formation of insoluble crystalline calcium phosphate deposits when used on a damaged corneal surface, and should therefore be used cautiously.

Influence of format on in vitro penetration of antibody fragments through porcine cornea

AIM

Antibody fragments, appropriately formulated, can penetrate through the ocular surface and thus have potential as therapeutic agents. The aim was to investigate the influence of protein fragment format on the kinetics and extent of ocular penetration in vitro.

METHODS

Immunoglobulin single chain variable domain fragments of a murine monoclonal antibody with specificity for rat CD4 were engineered with a 20 or 11 amino acid linker by assembly polymerase chain reaction, expressed in Escherichia coli and purified by chromatography. Fab fragments of the parental antibody were prepared by papain digestion. Antibody fragments were formulated with a penetration and a viscosity enhancer and were applied to the surface of perfused pig corneas for up to 10 hours in vitro. Penetration was quantified by flow cytometry on rat thymocytes.

RESULTS

20-mer antibody fragments formed natural monomers and dimers following purification that could be separately isolated, while 11-mer fragments were dimeric. All formats of fragment (20-mer monomers and dimers, 11-mer dimers, Fab) showed penetration through the pig cornea after 6 hours of intermittent topical administration.

CONCLUSION

Antibody fragments of different shapes and sizes can penetrate the cornea after topical administration, thereby increasing the potential of this class of proteins for topical ophthalmic use.

Lethal Epstein-Barr Virus Associated NK/T-Cell Lymphoma with Primary Manifestation in the Conjunctiva

BACKGROUND

Lethal midline granulomas (LMG) are very rare angiocentric NK/T-cell lymphomas in association with Epstein-Barr virus. LMG are reported mainly in East Asia occurring in immune compromised patients.

HISTORY AND SIGNS

A 41-year old male patient presented with a conjunctival swelling of his upper left eyelid. The lesion had increased over a period of 2 months despite topical corticosteroid treatment. Conjunctival biopsy revealed a highly malignant, CD3 + and BCL2 + extranodal T-cell lymphoma with features of an NK/T-cell origin (CD56 +, TIA + TCR-rearrangement: germline). All lymphoma cells were positive for Epstein-Barr virus RNA. The proliferation rate was highly elevated at 100 %.

THERAPY AND OUTCOME

Systemic 1 (st) cycle chemotherapy with cyclophosphamide, doxorubicin, vincristin and prednisone resulted in a complete remission of the swelling within 4 days. However, one week later a massive conjunctival tumour reappeared with only partial regression after combined chemo- and radiotherapy. The patient died within a month because of untreatable pancytopenia due to malignant bone marrow infiltration.

CONCLUSIONS

LMG is a rare but highly malignant Epstein-Barr virus associated NK/T-cell lymphoma that can occur in healthy, immune competent Caucasians. This is the first reported case of an LMG in an immune-competent Caucasian patient with primary ocular manifestation. The LMG has a high mortality rate despite systemic treatment and can be lethal within a few months or even weeks.

Pfeffersprayverletzungen des vorderen Augensegmentes

BACKGROUND

A wide variety of pepper sprays is currently available and gaining increasing popularity among both professional guardians and amateurs. Adverse side effects to the anterior segment of the eye are known but underestimated.

HISTORY AND SIGNS

We present two cases with severe corneal and conjunctival damage after accidental self injury by a pepper spray (Jet Protector Guardian Angel), benzyl alcohol 90.1 %, capsaicinoids 2.6 %).

THERAPY AND OUTCOME

Despite immediate and intensive irrigation, a complete epithelial defect, extensive ischemia to the limbus and the conjunctiva and a circular conjunctival chemosis were diagnosed. After slow re-epithelialization in both cases, a neurotrophic superficial keratitis, a reduced corneal sensibility and in one case deep stromal scarring were noted.

CONCLUSIONS

Pepper spray application to the eye might result in severe and permanent damage to the corneo-conjunctival tissue which is not adequately addressed in the current literature. From the present case reports arise the discussion whether the irritative and lipophilic capsacin/benzyl alcohol mixture or the pyrotechnical additives nitrocellulose und sinoxide are responsible for the anterior segment injuries.

Loa-Loa-Infektion des Auges - eine Fallserie

BACKGROUND

With increasing migration tropical diseases such as Loa loa infections are becoming more frequent in Europe. While the ocular diagnosis is usually straight forward, systemic work-up and treatment requires an interdisciplinary approach. We review the diagnostic and therapeutic work-up of ocular Loa loa infections based on a series of 4 cases that presented between 1998 and 2004.

HISTORY AND SIGNS

The first symptoms in all cases were ocular irritations occurring 2 months to 8 years after a trip to West Africa. One case presented with a swollen upper eyelid without a visible worm. In three patients microfilariae were detected in the blood.

THERAPY AND OUTCOME

In two cases visible subconjunctival worms could be removed under the slit lamp. Three cases required systemic treatment as inpatients while one case could be observed without systemic treatment. All 4 cases had a favourable outcome with complete eradication of the disease.

CONCLUSION

Surgical removal of adult Loa loa worms from the subconjunctival space only improves the ocular symptoms. An interdisciplinary approach (ophthalmology, infectious disease and parasitology) for a systemic work-up and treatment is usually required.

Follicular conjunctivitis caused by a mantle cell lymphoma

BACKGROUND

Lymphoma of the conjunctiva as part of a systemic disease is rare. The follicular appearance of the lymphocyte hyperplasia may mimic the clinical picture of infectious or allergic conjunctivitis. We report on a case of marked chronic follicular conjunctivitis, finally diagnosed as mantle cell lymphoma.

HISTORY AND SIGNS

A 52-year old male with a history of epiphora for one year, presented with follicular conjunctivitis in both eyes, a nodal mass in the upper right eyelid and nuchal lymphadenopathy. No infectious or allergic aetiology could be found. Conjunctival biopsy revealed a mantle cell lymphoma. Magnetic resonance tomography showed a bilateral spread into the orbital cavity. Other sites of involvement were the epipharynx and the cervical, axillary and paratracheal lymph nodes.

THERAPY AND OUTCOME

Chemotherapy with hyper-CVAD (cyclophosphamide, vincristine, doxorubicine, dexamethasone) was initiated. After 4 of 6 cycles, all clinical tumour manifestations had disappeared completely.

CONCLUSIONS

Conjunctival lymphoma may clinically resemble follicular conjunctivitis. Conjunctival biopsy may lead to early diagnosis and initiation of therapy.

Preclinical students: who are surgeons?1

BACKGROUND

The purpose of the present study was to determine how preclinical medical students formulate their career choice and to determine the origin of negative perceptions regarding surgery as a career.

MATERIALS AND METHODS

A qualitative study was performed with second-year medical students voluntarily participating in focus group study. Students with and without an interest in surgery attended. Topics discussed included factors influencing career choice, priorities, perceptions, exposure, and interactions with surgeons. Three investigators conducted independent content analysis.

RESULTS

Career choices for students interested in surgery originated primarily from premedical school experiences/interactions with surgeons. In contrast, students not interested in surgery made career choices during medical school and choices were shaped primarily by second-year preceptors. The main priority for students interested in surgery was personal happiness that was perceived as being significantly dependent upon career satisfaction. Students not interested in surgery tended to separate happiness derived from career versus family. Negative perceptions toward surgery were developed and reinforced by media, preceptors, and classmates. All students had minimal exposure to surgeons during preclinical years and generally agreed that increased involvement with surgeons would be beneficial, particularly through preclinical preceptorships.

CONCLUSIONS

Career choices of preclinical students interested in surgery were made prior to entering medical school, suggesting that outreach programs to high schools and colleges may beneficial. Negative perceptions about surgery develop through a variety of sources, including fellow classmates, preceptors, and the media. Surgeons need to take responsibility for these perceptions.

Normalisation of Ocular Pulse Amplitude after Embolisation of Dural Cavernous Sinus Arteriovenous Fistula

BACKGROUND

The difference in the ocular pulse amplitude between an individual's eyes may reflect abnormalities of the cerebrovascular circulation and has been shown to be helpful in assessing patients with cavernous sinus arteriovenous fistulas.

HISTORY AND SIGNS

A 71-year-old woman presented with episcleral injection, proptosis, bruit and retro-orbital pain on the left side. Ocular pulse amplitude as measured by dynamic contour tonometry was 4.38 +/- 1.23 mm Hg in the right and 9.57 +/- 2.71 mm Hg in the left eye. Angiography revealed the haemodynamics of a dural left cavernous sinus arteriovenous fistula.

THERAPY AND OUTCOME

Successful occlusion of the fistula was performed by transvenous embolisation. After embolisation, ocular pulse amplitude was 2.84 +/- 0.60 mm Hg in the right and 1.88 +/- 0.29 mm Hg in the left eye.

CONCLUSION

In this case of a dural arteriovenous fistula the ocular pulse amplitude as measured by dynamic contour tonometry parallels closely both clinical findings and neuroimaging.

Penetration of engineered antibody fragments into the eye

Antibodies are powerful immunotherapeutic agents but their use for treating ocular disorders is limited by their poor penetration into the eye. We hypothesized that antibody fragments of relatively small size might penetrate the cornea more readily. Monovalent single chain variable region (scFv) antibody fragments and divalent miniantibodies were engineered from existing monoclonal antibodies, expressed in a bacterial expression system, and purified by metal ion affinity chromatography. Corneoscleral preparations from normal pig and cat eyes were mounted in a corneal perfusion chamber. Intact antibodies and antibody fragments were applied topically to the anterior corneal surface over 12-h periods, and samples were collected from the artificial anterior chamber. Similar experiments were performed with whole enucleated pig and human eyes. Penetration of antibodies and fragments was quantified by high-sensitivity flow cytometry on appropriate target cells. Both monovalent scFv and divalent miniantibody fragments (but not whole immunoglobulin molecules) passed through de-epithelialized and intact corneas after topical administration, and could be detected by antigen binding. Addition of 0.5% sodium caprate facilitated penetration through intact corneas. Topically-applied scFv was found to penetrate into the anterior chamber fluid of rabbit eyes in vivo. The engineered fragments were stable and resistant to ocular proteases. Monovalent and divalent antibody constructs of molecular weight 28 kD and 67 kD, respectively, can penetrate through intact corneas into the anterior chamber, with retention of appropriate antigen-binding activity. Such constructs may form novel therapeutic agents for topical ophthalmic use.

A simple corneal perfusion chamber for drug penetration and toxicity studies

AIMS

Corneal perfusion chambers are important tools in the development and assessment of ophthalmic drugs. The aim of this study was to design and test a modified perfusion chamber suitable for topical application of drugs to isolated corneoscleral preparations, and which allowed continuous monitoring of endothelial cell function.

METHODS

A polycarbonate and stainless steel perfusion chamber was designed to clamp corneas in a horizontal plane suitable for topical drug delivery. Endothelial cell function was assessed by ultrasonic pachymetry and specular microscopy during perfusion. Epithelial barrier function was assessed by penetration of fluorescein. Leakage was examined by measuring penetration of a large protein, IgG. Tissue architecture after perfusion was examined by conventional histology.

RESULTS

Corneas maintained a functionally and morphologically intact endothelial monolayer during perfusion periods of up to 14 hours. The epithelial barrier function was well preserved. The tissue clamp sealed the preparation effectively against leakage of macromolecules.

CONCLUSION

The new chamber device forms a reliable tool for in vitro drug penetration and toxicity studies in isolated perfused corneoscleral tissue.

[Clinical evaluation of impression cytology in diagnosis of superficial viral infections]

BACKGROUND

Impression cytology is a non invasive technique for the diagnosis of external eye disease. As infected epithelial cells are losing their adhesion to neighbouring cells they are an ideal target for impression cytology. Despite its diagnostic potential impression cytology has not yet become a routine diagnostic tool because of technical inconvenience in use of conventional membranes. The aim of this study was to evaluate a practicable technique of impression cytology for the rapid diagnosis of superficial viral eye disease.

MATERIAL AND METHODS

52 patients with suspected viral conjunctivitis or keratitis underwent impression cytology with a Biopore membrane device. After air fixation immunologic detection tests using either peroxidase antiperoxidase or fluorescent techniques were performed directly on the membrane.

RESULTS AND CONCLUSIONS

21 of 38 patients with suspected Herpes-simplex-virus (HSV), 3 of 4 patients with suspected Varicella-Zoster-virus (VZV) and 2 of 10 patients with suspected Adenovirus infection had a positive result on the impression cytology membrane. These results were confirmed by virus cultures or polymerase chain reactions (PCR) a few days later. No patient with a negative impression cytology had a positive culture result. Using impression cytology and an immunodetection test results became available within 1 to 4 hours.

CONCLUSIONS

Impression cytology combined with immunologic detection tests is a rapid, sensitive and practicable diagnostic test for superficial viral eye diseases.

Improved impression cytology techniques for the immunopathological diagnosis of superficial viral infections

BACKGROUND

For epidemiological and therapeutic reasons early diagnosis of superficial viral infections is crucial. Conventional microbiological techniques are expensive, time consuming, and not sufficiently sensitive. In this study impression cytology techniques were evaluated to analyse their diagnostic potential in viral infections of the ocular surface.

METHOD

A Biopore membrane device instead of the original impression cytology technique was used to allow better quality and handling of the specimens. The impressions were processed, using monoclonal antibodies and immunoperoxidase or immunofluorescence techniques to assess the presence of herpes simplex virus, varicella zoster virus, or adenovirus antigens. Ocular surface specimens from healthy individuals (n = 10) and from patients with suspected viral surface disease (n = 19) were studied. Infected and non-infected cell cultures served as controls.

RESULTS

This modified technique of impression cytology allowed the collection of large conjunctival and corneal epithelial cell layers with excellent morphology. Immunocytological staining of these samples provided diagnostic results for all three viruses in patients with viral surface disease.

CONCLUSIONS

The use of Biopore membrane devices for the collection of ocular surface epithelia offers new diagnostic possibilities for external eye diseases. Immunopathological methods that are applied directly on these membrane devices can provide virological results within 1-4 hours. This contributes considerably to the clinical management of patients with infectious diseases of the ocular surface.

Intraluminal pressure modulates vascular contractility of perfused mesenteric resistance arteries. Altered response in hypertension

Intraluminal pressure may affect vascular contractility in both normotension and hypertension. To test this hypothesis, we studied mesenteric resistance arteries from normotensive humans as well as normotensive (WKY) and spontaneously hypertensive (SHR) rats (internal diameter 214 +/- 27, 201 +/- 6, and 172 +/- 6 microns, mean +/- SEM at 10 mm Hg). Vessels were mounted on glass cannulas and perfused in organ chambers filled with buffer solution at intraluminal pressures of 10 to 120 mm Hg; vasomotion was measured using a video dimension analyzer. Under baseline conditions (10 mm Hg), wall thickness was 36 +/- 4 microns in humans, 32 +/- 4 microns in WKY, and 47 +/- 2 microns in SHR (P less than .001). With increasing pressure, the diameter of human vessels increased up to 25 mm Hg and remained constant at higher pressures. In contrast, resistance arteries of normotensive and hypertensive rats exhibited an almost linear increase in diameter over the whole pressure range. In SHR, the pressure-diameter relationship was much flatter than that of WKY, indicating reduced compliance. In human arteries, the contraction to KCl was maximal at 25 mm Hg and averaged 40 +/- 6%. Both above and below 25 mm Hg, the response declined to a minimum of 17 +/- 2% at 120 mm Hg (P less than .01). Similar results were obtained in WKY rats. In contrast, the contractile response in SHR remained maximal over the entire pressure range studied (65 +/- 5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of endothelial L-arginine pathway in resistance arteries. Effect of age and hypertension

In conduit arteries, nitric oxide is formed from L-arginine in the endothelium and released after stimulation with acetylcholine. The contribution of the L-arginine pathway and the effects of age and hypertension on endothelium-dependent vascular regulation were studied, using a video dimension analyzer, in pressurized and perfused mesenteric resistance arteries of 8- and 16-20-week-old Wistar-Kyoto and spontaneously hypertensive rats. Norepinephrine and phenylephrine caused contractions, which were similarly augmented after removal of the endothelium. NG-Monomethyl-L-arginine, an inhibitor of nitric oxide formation, augmented the contraction, but less than endothelial removal. Acetylcholine caused endothelium-dependent relaxations that were much more pronounced with intraluminal than with extraluminal application. NG-Monomethyl-L-arginine, methylene blue, and hemoglobin only partially inhibited the response. With aging, the endothelium-dependent inhibition of the response to norepinephrine decreased in Wistar-Kyoto rats; in spontaneously hypertensive rats this inhibition was smaller as compared with age-matched Wistar-Kyoto rats. In Wistar-Kyoto rats, the difference between intraluminal and extraluminal activation became more pronounced in adult rats. In the adult but not the young spontaneously hypertensive rats, the response to intraluminal but not extraluminal acetylcholine was reduced as compared with Wistar-Kyoto rats. Thus, in mesenteric resistance arteries of the rat, nitric oxide is released from L-arginine under basal conditions and after stimulation with acetylcholine but only in part accounts for endothelium-dependent responses. With aging and hypertension, the inhibitory effects of the endothelium against norepinephrine-induced contractions decrease. In hypertension, the intraluminal but not extraluminal activation of the release of endothelium-derived relaxing factors is impaired.