New insights into amiodarone induced retinal and optic nerve toxicity: functional and structural changes.

Background: Amiodarone is widely used for heart arrhytmia. Previous studies have suggested the possibility of optic neuropathy with the chronic use of this drug. Objectives: To identify structural or functional changes in the retina and optic nerve in patients on chronic amiodarone therapy without visual complaints. Methods: This observational study included 15 eyes of 15 patients with cardiac arrythmia on chronic amiodarone treatment and 15 healthy matched subjects as a control group. All subjects underwent electrophysiological tests [pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), multifocal electroretinogram (mfERG), and optical coherence tomography (OCT) and angiography (OCTA)]. Results: There were no statistically significant differences between the two groups regarding the PVEP, PERG, and the mfERG parameters. Macular and optic nerve head OCT and OCTA have not shown statistically significant differences except for the morphological parameters of the optic disc (p = 0.008 for the horizontal and p = 0.013 for vertical cup/disc ratio and p = 0.045 for rim area). Conclusion: Patients on chronic amiodarone therapy have not shown evident structural or functional changes in the retinal or optic nerve as demonstrated by electrophysiological tests, OCT, and OCTA results compared to controls.

Optical coherence tomography and electrophysiological analysis of proptotic eyes due to thyroid-associated ophthalmopathy.

PURPOSE: To study the degree of morphological and functional changes in thyroid-associated ophthalmology (TAO) patients using optical coherence tomography and electrophysiological studies and investigate their clinical correlation. METHODS: A cross-sectional study including 40 patients with TAO and a control group with age- and sex-matched healthy subjects. All subjects underwent a complete ophthalmological examination, proptosis evaluation, spectral domain optical coherence tomography, and electrophysiological tests (pattern and multifocal electroretinograms, and visual evoked potentials). RESULTS: On multiple regression analysis, the degree of proptosis and P50 amplitude were the most important predictors of central foveal thickness (CFT) (ß = - 0.56 and 0.39 and p = 0.03 and 0.01, respectively); while duration of the disease, and clinical activity score (CAS) were the most important predictors of average RNFL thickness (ß = 0.67 and - 0.81 and p = 0.004 and < 0.001, respectively). CONCLUSION: In the absence of fundus changes, macular thinning along with functional alterations noticed by pattern and multifocal electroretinogram could indicate presence of subclinical retinopathy in TAO cases.

Correlation Between Optical Coherence Tomography and Photopic Negative Response of Flash Electroretinography in Ganglion Cell Complex Assessment in Glaucoma Patients.

Purpose: To investigate the correlation between the photopic negative response (PhNR) of the light-adapted flash electroretinography (ERG) and measurements of standard automated perimetry (SAP) and optical coherence tomography (OCT) in assessment of retinal ganglion cells' (RGCs) affection in glaucoma. Patients and Methods: A cross-sectional study included 40 eyes of glaucoma patients and 40 eyes of age- and gender-matched normal subjects. Participants underwent a complete ophthalmologic assessment, SAP, OCT, and light-adapted flash ERG using the extended PhNR protocol of the International Society for Clinical Electrophysiology of Vision (ISCEV). Glaucomatous eyes were divided into 3 subgroups: mild (n = 15), moderate (n = 11) and severe glaucoma (n = 14) according to the mean deviation (MD) of SAP. Measurements of SAP, OCT and ERG parameters were analyzed, and correlations between PhNR measurements and other study measurements were evaluated. Results: PhNR amplitudes and PhNR/b-wave ratios were significantly reduced in glaucoma cases compared to healthy controls, and they showed a significant and progressive decline across the three glaucoma subgroups (P < 0.05). An exception to this is PT (b-wave peak to PhNR trough) PhNR amplitude where its reduction was statistically non-significant when comparing between controls and mild glaucoma cases (P = 0.178), and between moderate and severe glaucoma cases (P = 0.714). PhNR amplitudes and PhNR/b-wave ratios correlated significantly with SAP and OCT parameters (P < 0.05). Conclusion: PhNR correlates well with SAP and OCT parameters in glaucoma assessment. PhNR could be a valuable supplementary tool for objective assessment of the RGCs' function in glaucoma.

Spanlastics nanovesicular ocular insert as a novel ocular delivery of travoprost: optimization using Box-Behnken design and in vivo evaluation.

Currently, travoprost is a synthetic prostaglandin F2α analogue used in the treatment of glaucoma, it is delivered by eye drop solution. Due to its very low bioavailability and patient non-compliance, the objective of the current study was to enhance its bioavailability, and prolong its release Spanlastic nano-vesicles gels were designed and optimized using Box-Behnken design. The optimized spanlastic nano-vesicles gel exhibited the lowest particle size (PS), polydispersity index (PDI) and the highest zeta potential (ZP), encapsulation efficiency (EE) and mucoadhesive strength was fabricated into spanlastic nano-vesicles ocular insert by solvent casting. In vivo studies showed enhanced bioavailability of travoprost spanlastic nano-vesicles gel and ocular insert compared to the marketed eye drops (travoswix®), as proven by their higher Cmax and AUC0-∞, in addition to being nonirritant to ocular surfaces. However, spanlastic nano-vesicles ocular insert showed more prolonged effect than spanlastic nano-vesicles gel. According to our study, it can be suggested that travoprost spanlastic nano-vesicles ocular insert is a novel ocular delivery system for glaucoma treatment.

Intravitreal methotrexate infusion for prophylaxis of proliferative vitreoretinopathy after pars plana vitrectomy for rhegmatogenous retinal detachment.

Background: Proliferative vitreoretinopathy (PVR) is the leading cause of recurrent retinal detachment after surgical repair of rhegmatogenous retinal detachment (RRD). Our study aimed to assess the efficacy and safety of intravitreal methotrexate infusion (IMI) for the prevention of PVR after pars plana vitrectomy (PPV) in eyes with RRD. Methods: This prospective comparative interventional study was conducted from September 2020 to November 2021 at Ain Shams University Hospitals, Egypt. We recruited a consecutive, non-randomized sample of 47 eyes of 47 patients with RRD undergoing PPV. Participants were allocated to a control group or an intervention group that received IMI during surgery. Each group was subdivided into subgroups of eyes at high-risk of developing PVR and eyes with established preoperative PVR grade C. Outcome measures at the 3-month postoperative follow-up were the rate of retinal attachment, incidence of PVR, reoperation rate to flatten the retina, and changes in the retina and/or optic nerve function as assessed by full-field electroretinogram and flash visual evoked potential. Results: Data from 47 eyes (23 and 24 eyes in the intervention and control groups, respectively) were evaluated. Subgroups IA, IB, and IIB each included 12 eyes, subgroup IIA included 11 eyes, and all subgroups had comparable sex ratios and age distributions. Postoperative PVR at 1 month and between 1 and 3 months was present in 13% and 4% of eyes in the intervention group, respectively. Reoperation to flatten the retina was required in 2 (9%) eyes in the intervention group, while 22 eyes (96%) had complete flattening of the retina at 3 months. No significant differences were found between the study groups and the corresponding subgroups regarding the outcome measures (all P > 0.05). No adverse events attributable to IMI were detected up to 3 months postoperatively. Conclusions: Although IMI was safe for intraocular use in eyes with RRD and PVR grade C or a high risk of developing PVR, it did not affect the anatomical success rate or development of PVR up to 3 months after PPV. Further multicenter randomized clinical trials with longer follow-up periods and larger sample sizes are needed to verify these preliminary outcomes.

Choroidal thickness in relation to urinary albumin excretion rate in type 2 diabetes mellitus without retinopathy.

BACKGROUND: To evaluate choroidal thickness (CT) in diabetic patients without diabetic retinopathy (DR) in relation to the urinary albumin excretion rate (UAER). METHODS: This is a prospective case-control study that included a consecutive sample of 120 patients with type 2 diabetes without clinically evident DR and a group of 60 matched healthy controls. Diabetic patients were included in two groups according to their UAER (normoalbuminuria and microalbuminuria). Complete ophthalmological examination was performed followed by optical coherence tomography (SD-OCT) for retinal and choroidal assessment. Twenty-four-hour urine samples were collected for UAER and blood samples for HbA1c and serum creatinine were obtained. RESULTS: The study included 180 eyes from 180 subjects in three groups. Patients with higher levels of albuminuria had a thinner choroid than normal controls, with decremental thinning as albuminuria progressed. Diabetics with normoalbuminuria showed no significant differences from controls. Choroidal thickness showed a significant moderate negative correlation with UAER (r = - 0.58, p < 0.001). Multiple regression analyses for diabetic patients with microalbuminuria demonstrated that UAER is the most important determinant of subfoveal choroidal thickness (SFCT) (p < 0.001). CONCLUSIONS: Decreased CT was significantly correlated with UAER in diabetic patients without retinopathy and otherwise normal kidney functions. This decrease in thickness might be a predictor of DR.

Multifocal visual evoked potential for evaluation of open-angle glaucoma.

Background: To correlate multifocal visual evoked potential (mfVEP) findings with static automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in eyes with primary open- angle glaucoma (POAG). Methods: This cross-sectional study included a consecutive sample of 40 eyes of 40 patients with POAG. The participants underwent a complete ophthalmologic assessment, axial length (AL) measurement, and assessments with SAP, SD-OCT, and mfVEP. Results: POAG cases were aged 49.70 (14.16) years (mean [SD]) and most were females (n = 24, 60%). For eyes of patients with POAG, the mfVEP upper-ring signal-to-noise ratio (SNR) showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.33; P = 0.038), and a significant positive correlation with the superior hemifield of the visual field (VF) and the inferior-quadrant retinal nerve fiber layer (RNFL) thickness (r = + 0.34; P = 0.030; r = + 0.51; P < 0.001, respectively). Similarly, the mfVEP lower-ring SNR showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.36; P = 0.024) and a significant positive correlation with the inferior hemifield of the VF and superior quadrant RNFL thickness (r = + 0.55; P < 0.001 and r = + 0.70; P < 0.001, respectively). Conclusions: mfVEP is a promising tool for objective assessment of the VF in patients with POAG, as it is positively correlated with the VF and OCT RNFL thickness. Future longitudinal studies with a larger sample size and a specific glaucoma subtype, along with multiple follow-up evaluations, are warranted to confirm our preliminary results.

EFFECT OF SMOKING ON MACULAR FUNCTION AND STRUCTURE IN ACTIVE SMOKERS VERSUS PASSIVE SMOKERS.

PURPOSE: The aim is to study the effects of cigarette smoking on the structural and functional alterations of the macula in eyes of healthy young smokers. METHODS: Cross-sectional clinical study included 100 active smokers (Group 1) and 100 age- and sex-matched healthy passive smokers (Group 2). All participants underwent a complete ophthalmologic assessment, axial length measurement, central corneal thickness measurement, spectral domain optical coherence tomography, and multifocal electroretinogram. Urine samples were collected to measure urinary levels of cotinine and creatinine with subsequent calculation of the cotinine creatinine ratio. RESULTS: Central foveal thickness (255.62 ± 17.23 and 264.75 ± 17.35 µm, respectively, with P = 0.0003) and subfoveal choroidal thickness (377.48 ± 30.32 and 385.08 ± 21.10 µm, respectively, with P = 0.04) were significantly lower in active smokers than those of passive smokers. Retinal response density of ring 1 (31.08 ± 2.29 and 33.46 ± 3.83 nV/deg, respectively, with P < 0.001) and Ring 1 (R1) P1 amplitude (0.81 ± 0.07 and 0.95 ± 0.16 µV, respectively, with P < 0.001) were significantly lower, whereas R1 P1 latency (43.02 ± 0.97 and 40.39 ± 2.08 milliseconds, respectively, with P < 0.001) was significantly longer in active smokers than those of passive smokers. The mf-ERG ring ratios were significantly lower in the active smokers than those of passive smokers. CONCLUSION: In the absence of clinically apparent foveal toxicity, CFT, SFCT together with ring amplitude ratio could be used as good predictors of subclinical nicotine induced foveal changes.

Relation of anthropometric measurements to ocular biometric changes and refractive error in children with thalassemia.

PURPOSE: To evaluate and correlate anthropometric, biometric, and refractive error changes in thalassemia major (TM). METHODS: One hundred children with TM and another hundred healthy controls were recruited. Height, weight, body mass index (BMI), and occipitofrontal circumference (OFC) were the anthropometric parameters recorded. Full ophthalmologic examination was performed, including best-corrected visual acuity, cycloplegic refraction, slit-lamp examination, Goldmann applanation tonometry, indirect ophthalmoscopy, keratometry (K readings), and ocular biometry. RESULTS: Compared to controls, children with TM were shorter and lighter, with a smaller BMI (p<0.001); however, no significant difference existed in OFC. Regarding ocular biometric data, patients with thalassemia had steeper mean K readings (p = 0.03), shorter axial length (AXL) (p = 0.005), shorter vitreous chamber depth (p<0.001), and thicker crystalline lens (p<0.001) than controls. Patients with thalassemia had a significant myopic shift (p = 0.003). Multiple regression analyses only showed a significant correlation between corneal astigmatism and both weight and height (ß = -0.05 and p = 0.03 and ß = 0.06 and p = 0.04, respectively). Spherical equivalent was significantly correlated to K readings, lens thickness, and anterior chamber depth (p<0.0001 for all parameters). CONCLUSIONS: Compared to controls, children with TM have significant retardation in general and ocular growth (smaller BMI and shorter AXL). Ocular growth changes probably resulted in compensatory biometric changes (steeper corneas and thicker lenses) to reach emmetropization, with an exaggerated response and subsequent myopic shift. However, growth retardation is not directly related to ocular growth changes, myopic shift, or variations in biometric parameters.

Pattern Visual Evoked Potential, Pattern Electroretinogram, and Retinal Nerve Fiber Layer Thickness in Patients with Migraine during and after Aura.

PURPOSE: To study pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), and retinal nerve fiber layer (RNFL) thickness in patients with migraine during and after aura. MATERIALS AND METHODS: We included 60 eyes of 60 patients with migraine (Group 1) and 30 healthy volunteers (30 eyes) as controls (Group 2). Group 1 was studied twice, during a visual aura (1-a) and in between attacks (1-b). All participants underwent full ophthalmological examination, PVEP, PERG, and optical coherence tomographyOCT imaging of the RNFL thickness for each patient. RESULTS: RNFL thickness was found to be thinner in patients during the aura compared to controls. It increased significantly post-aura but remained lower than the controls. Prolonged P100 latency and decreased amplitude were found in patients during aura compared to controls with significant change in between attacks to values comparable to the controls. We found prolonged N95 latency and decreased amplitude in patients during aura compared to controls with significant change post-aura to values comparable to the controls. There was positive correlation between average RNFL thicknesses and VA and spherical equivalent; but it showed negative correlation with duration of migraine, attack duration, and aura duration. Multiple regression analysis showed that the most important determinants of average RNFL thickness in patients of migraine were attack and aura duration (beta = -0.21 and -0.26 and p = 0.03 and 0.04, respectively). CONCLUSION: Migraine attacks impose both functional and structural retinal changes. The functional changes are fully reversible after the aura but not the structural ones. So, vigorous prevention of migraine attacks would be protective for retina.

Effect of Active and Passive Smoking on Retinal Nerve Fibre Layer and Ganglion Cell Complex.

Aim. To evaluate the possible structural and functional changes in the retinal nerve fibre layer (RNFL) and the ganglion cell complex (GCC) of chronic smokers and compare them with those of passive healthy smokers using spectral domain optical coherence tomography (SD-OCT) and pattern electroretinogram (PERG). Materials and Methods. We include 80 active chronic smokers and 80 age- and sex-matched healthy passive smokers. After a full ophthalmological examination, SD-OCT and PERG were tested for all participants. Urinary levels of cotinine and creatinine with subsequent calculation of the cotinine creatinine ratio (CCR). Results. Inferior and superior quadrants of RNFL were thinner in group I, but nasal and temporal quadrants did not show significant difference between the groups. There were no significant differences of GCC values between the two groups. There was no significant difference of PERG-P50 amplitude and latency; however, PERG-N95 showed significant difference between the two groups. Multiple regression analyses demonstrated that the number of cigarettes/day, urinary cotinine, and PERG-N95 amplitude are the most important determinants for both superior and inferior RNFL thicknesses. Conclusion. RNFL thickness decreases in chronic, healthy, heavy cigarette smokers, and this thinning is related to the number of cigarettes/day, urinary cotinine, and PERG-N95 latency and amplitude.

Correlation between choroidal thickness and degree of myopia assessed with enhanced depth imaging optical coherence tomography.

PURPOSE: To assess the choroidal thickness in different degrees of myopia using enhanced depth imaging optical coherence tomography (EDI-OCT) compared with healthy subjects. METHODS: We included 240 patients with myopia and 60 emmetropes as controls. Participants underwent full ophthalmologic examination, axial length measurement, and EDI-OCT imaging of the choroid. Choroidal thickness (CT) was measured at 5 locations, including subfoveal (SFCT), 2 mm nasal, temporal, upper, and lower to fovea. RESULTS: Choroidal thickness was significantly lower in myopic eyes compared to controls. Regardless of the degree of myopia, nasal regions showed the lowest CT with decremental pattern with advance of myopia (low myopia 279.00 ± 24.50 µm, moderate myopia 269.58 ± 20.69 µm, high myopia 189.58 ± 25.95 µm, advanced myopia 96.75 ± 24.83 µm). Highest CT was variable according to the degree of myopia with decremental pattern with advance of myopia (low myopia in subfoveal region 354.40 ± 35.14 µm, moderate myopia in temporal region 337.87 ± 35.75 µm, high myopia in lower region 312.15 ± 38.90 µm, and advanced myopia in upper region 201.25 ± 18.27 µm). Axial length showed significant negative correlation with SFCT and CT in different studied regions. CONCLUSIONS: Different degrees of myopia showed thinner choroidal thickness than that of normal control eyes with decremental thinning with progress of myopia. This might be secondary to the longer axial length, which was the determining factor in some locations such as subfoveal, nasal, and upper CT.

Relationship between functional and structural retinal changes in myopic eyes.

BACKGROUND: The aim of this study was to investigate the retinal structure in different grades of myopia and correlate it with the functional changes detected with multifocal electroretinogram (mf-ERG) and try to show the most important determining factors. METHODS: The study included 80 participants divided into four groups according to their spherical equivalent refractive error, namely, emmetropia (within ± 0.50 D), mild myopia group (greater than -0.50 to -3.00 D), moderate myopia group (more than -3.00 to -6.00 D) and high myopia group (greater than -6.00 D). Full ophthalmologic examination was performed for all participants, including visual acuity (VA), slitlamp examination, Goldmann applanation tonometry, indirect ophthalmoscopy, axial length (AL) measurement, retinal nerve fibre layer thickness assessment and mf-ERG stimulation. RESULTS: Axial length was significantly higher in myopes than emmetropes; also it was higher the greater the degree of myopia. There was a reduction in the amplitude and prolongation of implicit times of mf-ERG in myopia. Also P1 implicit time of the mf-ERG response was prolonged the greater the degree of myopia. The retinal nerve fibre layer was significantly thinner in myopic groups than the emmetropic group. The thinning of the retinal nerve fibre layer increased the more the degree of myopia. Multiple regression analysis of myopic patients showed that AL is the most important determinant of most of the mf-ERG five-rings retinal response density (RRD), mf-ERG four-quadrant (Q) RRD, most of the five-rings P1 amplitude and all five-rings latencies. The most important determinant factors of mean Q RRD were VA, AL and retinal nerve fibre layer thickness. CONCLUSION: The retina of the myope is subject to both structural and functional alterations compared to that of the emmetrope. Significant correlations exist between the functional and structural changes and can be explained on bases of longer AL and increasing myopic refraction.

ELECTRORETINOGRAPHIC AND VISUAL-EVOKED POTENTIAL CHANGES IN RELATION TO CHELATION MODALITY IN CHILDREN WITH THALASSEMIA.

PURPOSE: To evaluate possible benefits of using electrophysiological investigations for detecting retinal and visual pathway changes and correlating them with chelation modality in children with thalassemia. METHODS: This study included 60 patients on single oral iron chelator (deferasirox) (Group 1), 60 on deferoxamine chelator (Group 2), and 60 controls (Group 3). Participants underwent full ophthalmologic examination, pattern visual-evoked potential, pattern electroretinogram, and multifocal electroretinogram. RESULTS: Fundus showed no abnormalities. Multifocal electroretinogram mean P1 amplitude showed statistically significant differences in all 5 rings, amplitudes being significantly lower in Groups 1 and 2 than Group 3; moreover, significantly lower in Group 2 than Group 1. There was a statistically significant difference between groups regarding P50 wave latency and N35-P50 of pattern electroretinogram amplitude (P < 0.001 and P < 0.001, respectively). However, there were no statistically significant differences between groups regarding N95 wave of pattern electroretinogram and pattern visual-evoked potential waves' amplitude and latency. Multiple regression analyses illustrated that chelator was the most important determinant for multifocal electroretinogram and P50 parameters. CONCLUSION: Preclinical electrophysiologic changes existed in thalassemics, more obvious in those on deferoxamine. Electrophysiologic studies analysis denotes an early toxic macular insult rather than optic nerve affection. Thus, regular follow-up using multifocal electroretinogram and pattern electroretinogram is recommended.

CORRELATION BETWEEN SUBFOVEAL CHOROIDAL THICKNESS AND FOVEAL THICKNESS IN THALASSEMIC PATIENTS.

PURPOSE: To assess the impact of two iron chelation modalities in thalassemic patients on foveal and subfoveal choroidal thickness. METHODS: The study included 60 ß-thalassemia major patients. They included 30 patients on oral deferasirox after a period of subcutaneous deferoxamine (Group 2) and 30 patients on subcutaneous deferoxamine (Group 3). Thirty age- and sex-matched healthy children were included as a control group (Group 1). All participants underwent a complete ophthalmologic evaluation and Spectral Domain Optical Coherence Tomography. RESULTS: Age, gender, intraocular pressure, best-corrected visual acuity, and refraction were not statistically different between the three studied groups. Ferritin level, pretransfusion hemoglobin, serum iron, and duration of thalassemia were not statistically different between the two thalassemic groups. Foveal thickness in Group 1 (225.15 ± 17.35 µm) was statistically higher than in Group 2 (210.53 ± 21.73 µm) (P < 0.001) and Group 3 (200.15 ± 7.34 µm) (P < 0.001). It was statistically higher in Group 2 than in Group 3 (P = 0.001). Subfoveal choroidal thickness in Group 1 (279.70 ± 32.54 µm) was statistically higher than in Group 2 (255.80 ± 19.20 µm) (P < 0.001) and Group 3 (248.28 ± 20.43 µm) (P < 0.001). It was statistically higher in Group 2 than in Group 3 (P < 0.05). CONCLUSION: Thalassemic patients can develop a significant decrease in foveal thickness because of the inevitable use of chelation therapy. Deferoxamine as a chelating agent can affect foveal thickness more than the oral form (deferasirox).

Short wavelength automated perimetry can detect visual field changes in diabetic patients without retinopathy.

PURPOSE: The purpose of the following study is to compare short wave automated perimetry (SWAP) versus standard automated perimetry (SAP) for early detection of diabetic retinopathy (DR). MATERIALS AND METHODS: A total of 40 diabetic patients, divided into group I without DR (20 patients = 40 eyes) and group II with mild non-proliferative DR (20 patients = 40 eyes) were included. They were tested with central 24-2 threshold test with both shortwave and SAP to compare sensitivity values and local visual field indices in both of them. A total of 20 healthy age and gender matched subjects were assessed as a control group. RESULTS: Control group showed no differences between SWAP and SAP regarding mean deviation (MD), corrected pattern standard deviation (CPSD) or short fluctuations (SF). In group I, MD showed significant more deflection in SWAP (-4.44 ± 2.02 dB) compared to SAP (-0.96 ± 1.81 dB) (P = 0.000002). However, CPSD and SF were not different between SWAP and SAP. In group II, MD and SF showed significantly different values in SWAP (-5.75 ± 3.11 dB and 2.0 ± 0.95) compared to SAP (-3.91 ± 2.87 dB and 2.86 ± 1.23) (P = 0.01 and 0.006 respectively). There are no differences regarding CPSD between SWAP and SAP. The SWAP technique was significantly more sensitive than SAP in patients without retinopathy (p), but no difference exists between the two techniques in patients with non-proliferative DR. CONCLUSION: The SWAP technique has a higher yield and efficacy to pick up abnormal findings in diabetic patients without overt retinopathy rather than patients with clinical retinopathy.

Enhancement of the ocular therapeutic effect of prednisolone acetate by liposomal entrapment.

Eye drops account for 90% of ophthalmic formulations despite of the rapid precorneal drug loss. Our aim is to test the effect of positive charge induction and the subsequent size reduction on the efficiency of liposomes as ocular drug delivery system for the lipophilic drug prednisolone acetate (PSA). Different formulations of PSA-loaded liposomes, positive multilamellar liposomes (pMLV), positive small (nano-sized) unilamellar liposomes (pSUV) and neutral multilamellar liposomes (nMLV), were prepared. These formulations were characterized by measuring surface charge, size distribution, entrapment efficiency, release rate, and ability to deliver PSA across the cornea. In vitro studies showed that positive charge induction reduces the transcorneal flux (about 1.9-fold lower than nMLV), while the subsequent size reduction results in higher flux (about 1.2-fold higher than nMLV). But in vivo results revealed that pSUV produced more concentrations of PSA in aqueous humor than nMLV (P < 0.05) suggesting greater chance for drug penetration, pSUV were more effective than nMLV in this regard (P < 0.05). As revealed by in vivo studies and ophthalmic examinations, positive charge induction and the subsequent size reduction increased the efficiency of liposomes as ocular drug delivery system for PSA.

Passive smoking as a risk factor of dry eye in children.

Purpose. Adult active smoking is a risk factor for dry eye. We hypothesize that passive smoking in children can also produce the same effects. Methods. We included 112 school children presenting with eye discomfort. Assessment of eye dryness and its severity levels depending on symptoms of dry eye, visual symptoms, tear breakup time (TBUT), Schirmer-1 test, and corneal fluorescein staining were done for all of them. Exposure to cigarette smoking was assessed by history-taking and urinary cotinine levels. Results. Dry eye was found in 80/112 children. Passive smoking was documented in 76/112 children. Number of cigarettes to which the child was exposed per day and the duration of exposure to passive smoking were significantly higher in children with dry eye compared to those without. Urinary cotinine, and cotinine/creatinine ratio (CCR) was significantly higher in children with dry eye compared to those without dry eye. Multiregression analysis showed that the most important determinants of dry eye were CCR and number of cigarettes/day. Conclusion. Passive smoking represents a significant risk factor of dry eye in children comparable to that shown with active adult smoking. Male children are more prone to this effect.

Passive smoking exposure might be associated with hypermetropia.

PURPOSE: The aim of the study was to explore the relationship between nicotine exposure in children via passive smoking and the refractive errors of these children. METHODS: The study included 300 children between the age of 5 and 12 years. Children were subjected to detailed history taking with special emphasis on the degree of exposure to passive smoke. They underwent a complete ophthalmological evaluation including cycloplegic refraction. Urine samples were collected to measure urinary levels of cotinine and creatinine with subsequent calculation of the cotinine creatinine ratio (CCR). RESULTS: The refractive error assessment indicated 122 hypermetropic (40.7%), 86 myopic (28.7%) and 92 emmetropic (30.7%) children. Gender and age were not statistically different between the three groups. Urinary cotinine was significantly higher in the hypermetropic than myopic and emmetropic groups (p < 0.0001). Moreover, it was significantly higher in the emmetropic group than the myopic one (p = 0.02). Cotinine/creatinine ratio (CCR) and the parental number of cigarettes smoked per day showed the same pattern as urinary cotinine. Considering all 300 data, the spherical equivalent refractive error was significantly correlated with the number of cigarettes smoked by the parents, CCR and urinary cotinine levels cotinine (p < 0.0001 for all correlations). CONCLUSION: Passive smoking indices were related to the degree of refractive error and children with hypermetropia showed significantly higher passive smoking indices. We suggest that passive smoking might be associated with a refractive error shift towards hypermetropia.