A 31-year-old female patient with refractive error in both eyes underwent small incision lenticule extraction. On the 4th day after surgery, arc-shaped peripheral corneal infiltrates appeared in the right eye. Tobramycin and dexamethasone eye drops, 0.3% gatifloxacin eye drops, and a corneal bandage lens were applied to the eye. After bacterial infection was ruled out, dexamethasone sodium phosphate was injected subconjunctivally near the corneal lesion. The symptoms improved and the corneal lesion subsided afterwards.

A man in his 70s on regular follow-up with an ophthalmologist for 10 years presented with blurry vision in his right eye for 4 days. He was diagnosed with elevated intraocular pressure (IOP) bilaterally 18 months earlier and treated with antiglaucoma eye-drops. On direct questioning, he admitted to using fixed combination tobramycin 0.3%/dexamethasone 0.1% eye-drops frequently to relieve ocular redness and discomfort in both eyes for 3.5 years without his ophthalmologist's knowledge. Examination disclosed markedly elevated IOP, advanced optic disc cupping and tunnel vision due to steroid-induced glaucoma bilaterally. After cessation of the eye-drops and 2 weeks of antiglaucoma therapy, his IOP returned to normal and his visual field remained stable for 4 years.Our case highlights the danger of habitual self-treatment of prescription medications containing corticosteroids and the importance of taking a detailed medication history in the diagnosis and management of steroid-induced glaucoma.

Aminoglycosides (AGs) are a class of broad spectrum antibiotics that have bactericidal activity against some aerobic gram-positive and gram-negative organisms. AGs have been extensively employed in animal husbandry for the treatment of bacterial infections or growth promotion. Many countries have issued strict maximum residue levels (MRLs) for AGs in many animal-origin foods. Analysis of AGs is quite challenging due to their physicochemical properties. The lack of any notable chromophores or fluorophores makes direct detection using ultraviolet (UV) or fluorescence (FLR) spectroscopy unfeasible. Therefore, AGs must be derivatized before they can be analyzed by UV or FLR detection techniques. However, the sensitivity of such derivatization methods is relatively low. Methods based on chromatographic analysis coupled with tandem mass spectrometric detection are emerging as the most common way of identification and quantification. The retention of AGs on reversed-phase column is poor due to the presence of various amino and hydroxyl groups in their structures. Therefore, ion-pair chromatography has reportedly been used to improve the retention of AGs. However, electrospray ionization-mass spectrometric detection was hampered by using an ion pairing reagent due to the suppression of ionization. In this study, a method based on mixed-mode ion exchange liquid chromatography-tandem mass spectrometry was developed for the determination of ten AGs residues (streptomycin, dihydrostreptomycin, hygromycin B, kanamycin, amikacin, tobramycin, apramycin, spectinomycin, neomycin, and gentamycin) in eggs. The main factors governing the method, such as the type of chromatographic column used, the type and proportion of the mobile phase used, mass spectroscopy parameters, type and volume of the extraction solvent used, pH, and the type of solid phase extraction (SPE) column, were investigated during sample pretreatment and instrument analysis. The residues of AGs in the test samples were extracted by ultrasonication with 10 mmol/L ammonium acetate buffer solution (comprising 0.4 mmol/L EDTA and 50 g/L trichloroacetic acid). After adjusting the pH, the AG residues in the sample were purified and enriched using a PRiME HLB SPE column. The target analytes were separated on a SIELC Obelisc R column (150 mm×2.1mm, 5 μm), the column temperature being 40 ℃, the flow rate being 0.3 mL/min, and the injection volume being 5 μL. Gradient elution was carried out with acetonitrile and 1.0%(v/v) formic acid aqueous solution (including 1 mmol/L ammonium formate) as the mobile phases. The detection was performed by electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in multiple reaction monitoring (MRM) mode. The retention times and ionic ratios were used for qualitative analysis, and the peak areas were used for quantitative analysis by the external standard method. Good correlation coefficients exceeding 0.99 were observed for all the AGs in the concentration range of 5-200 μg/L under the optimum conditions. The limits of detection (LODs, S/N ≥ 3) and limits of quantification (LOQs, S/N≥10) for the ten AGs were 2-5 μg/kg and 5-10 μg/kg, respectively. The recoveries ranged from 68.1% to 111.3% (n=6) at three levels (LODs, 20 μg/kg, and 100 μg/kg) in spiked blank egg samples, and the relative standard deviations were 1.2%-12.3%. The matrix effects of the analytes were between 0.3% and 94.3% after purification on the PRiME HLB column. The applicability of the method was validated by analyzing egg samples purchased from local markets. Overall, the method of mixed-mode ion exchange liquid chromatography-tandem mass spectrometry has proven to be a reliable and powerful technique for the simultaneous quantification and confirmation of ten AGs without using an ion pair reagent. Moreover, the clean-up step only required a kind of PRiME HLB sorbent cartridge. The relative parameter data of established method were consistent with GB/T 27404-2008. With simple pretreatment, rapid determination and high sensitivity, the method can be used in the determination of AGs in eggs.

Corticosteroids are known to cause many ocular and systemic side effects when administered by oral or parenteral routes. Corticosteroid induced systemic toxicity secondary to topical steroid eye drops is rare. A 6-week-old, male infant was brought to our tertiary eye care center with bilateral congenital cataracts. The child underwent phacoaspiration with primary posterior capsulotomy without intraocular lens implantation in both eyes at an interval of 6 weeks. Child was initiated on topical betamethsone 0.1% eight times a day, tobramycin 0.3% six times a day, homatropine 2% twice a day, and carboxymethylcellulose 0.5% four times a day. Two and four weeks later he underwent surgical membranectomy in the right and left eye respectively followed by frequent use of topical steroids, initially given 1 hourly and then tapered weekly in the follow-up period. The patient showed increase in intraocular pressure and gain in body weight along with development of cushingoid habitus nearly 6 to 8 weeks after starting topical steroids. These side effects started weaning off following the reduction in dose of topical steroids, suggesting the role of the corticosteroid-related systemic side effects. This case highlights the serious systemic side effects secondary to increased frequency and duration of topical corticosteroid use in infancy. Hence, dosage of topical steroids should be adjusted in its therapeutic range to prevent their ocular and systemic side effects. Therefore, close monitoring is advocated for children using topical corticosteroids to prevent serious ocular and systemic side effects.