A comparative study between 10-MHz and 15-MHz ultrasound probes for retinal evaluation in silicone-oil-filled globes.

PURPOSE: To compare 10-MHz and 15-MHz B-scan probes regarding the detection and localization of retinal detachment (RD) in silicone-oil-filled eyes. METHODS: This cross-sectional observational study included 100 eyes (98 patients) -having media opacity precluding fundus examination- scheduled for silicone-oil removal. Patients were examined in the sitting-position using both frequencies one week preoperatively. Longitudinal and transverse scans were taken in primary-gaze, inferior, inferonasal, and inferotemporal positions to detect the presence/absence and extent of RD. Patients were sub-grouped according to axial lengths (AXLs), state of silicone emulsification, and globe filling. Agreement between sonographic and intraoperative observations was compared. RESULTS: No statistically significant differences were found between 15-MHz and intra-operative findings regarding RD detection (P = 0.752) and accurate localization of inferior, inferonasal, and inferotemporal RD (P = 0.279, 0.606, and 0.599). There were statistically significant differences between 10-MHz and intra-operative findings regarding RD detection and localization (P < 0.001). The 15-MHz probe was superior to 10-MHz probe regarding the accuracy of RD detection and localization (94% and 47%, respectively). The accuracy of 15-MHz probe was 88%, 83%, and 85% in detecting and localizing inferior, inferonasal, and inferotemporal RD compared to 45%, 60%, and 62% with 10-MHz probe. The 15-MHz probe showed better sensitivity while 10-MHz probe showed better accuracy in eyes with short AXLs. The 10-MHz probe showed better sensitivity in patients with sonographic emulsification while15-MHz probe had better sensitivity in detecting vitreoretinal-interface disorders. CONCLUSION: The 15-MHz B-scan probe is more accurate in detecting and localizing recurrent RD in silicone-oil-filled globes with higher sensitivity in detecting vitreoretinal-interface disorders.

Effect of pneumatic vitreolysis in management of patients with symptomatic focal vitreomacular traction.

PURPOSE: To evaluate the efficacy of single intravitreal injection of an expansile concentration of sulphur hexafluoride gas (SF6) in treating patients with symptomatic focal vitreomacular traction (VMT) documented by spectral domain optical coherence tomography (SD-OCT) preoperatively. METHODS: This is a prospective interventional case series including 30 eyes of 29 patients with symptomatic focal VMT evident on SD-OCT. Pre-operatively, mean best corrected visual acuity (BCVA) was 20/125 (range 20/400-20/40). Mean central foveal thickness (CFT) was 382 µm (range 149-576 µm; SD ± 91.88). All eyes received single intravitreal injection of 0.3 mL of 100% SF6 gas. Postoperatively, we performed SD-OCT at one week, one month, and three months for all eyes. Primary outcome measure was release of VMT. Secondary outcome measures were changes in postoperative BCVA andCFT. RESULTS: Overall, VMT release occurred in 24 of 30 eyes by the final follow-up visit (80% final release rate); furthermore, 76.9% of eyes with diabetic maculopathy and 25% of eyes with concurrent epiretinal membrane (ERM) had successful VMT release. VMT release was documented on SD-OCT at an average of 3 weeks (range, 1-12 weeks). The rate of release in phakic eyes was 90% (18 of 20 eyes) versus 60% in pseudophakic eyes (6 of 10 eyes). One patient developed a retinal break at upper nasal retina after two weeks of injection. CONCLUSION: Pneumatic vitreolysis (PVL) with limited face-down position is a viable option for treating focal VMT with few adverse events. Further studies are needed to evaluate its indications, benefits, and risks.

Evaluation of Central and Peripheral Corneal Thicknesses in Patients with Systemic Lupus Erythematosus.

PURPOSE: To evaluate the corneal pachymetric and topographic parameters of systemic Lupus Erythematosus (SLE) patients using Dual Scheimpflug Imaging. METHODS: This observational cross-sectional controlled study included the right eye of 30 SLE patients and 30 age-matched controls. Corneal measurements were acquired by dual Scheimpflug imaging including anterior and posterior corneal curvatures, central, mid-peripheral corneal thickness (measured at the 5 mm zone) and peripheral pachymetry (measured at the 7 mm zone). SLE disease activity index (SLEDAI) was calculated and correlated with corneal pachymetry. RESULTS: SLE patients had significantly thicker corneal periphery than controls. Mean central corneal pachymetry was 530.4± 27.3 microns (SD) in SLE and 547.5±31.5 microns (SD) in control group, p = 0.032. The corneal periphery - except superiorly - was significantly thicker in SLE patients than controls (p ˂0.001). Nasal peripheral corneal thickness positively correlated with disease activity index SLEDAI (p=0.03). CONCLUSION: SLE patients present with thicker corneal periphery than controls characteristically sparing the superior quadrant. Possible corneal photosensitivity leading to peripheral immune complex deposition as well as flatter posterior corneal surface at the periphery are proposed explanations for these findings.

Adherence to Intravitreal Anti-Vascular Endothelial Growth Factor (Anti-VEGF) Drugs in Diabetic Macular Edema in an Egyptian Population: A Health Belief Model.

PURPOSE: To determine the factors that influence the adherence to follow-up and injections in patients with diabetic macular edema (DME) utilizing a health belief model (HBM) as a theoretical framework, and using demographic variables and knowledge about DME as factors that influence individual perceptions. MATERIAL AND METHODS: A structured questionnaire was developed utilizing the six domains of HBM and using knowledge and other demographics as modifying variables. The questionnaire was checked for validity and reliability, and then used to collect data from patients with DME who were candidates for intravitreal injections according to pro-re-nata regimen, and completed one year after the first injection. Univariate and multivariable analysis was performed to identify factors associated with poor adherence. RESULTS: Of all 343 included patients (168 women and 175 men; mean [SD] age, 58[10] years, 71 (20.7 %) patients dropped visits and/or injections during the first year of treatment. Mean number of dropped injections was 1.32 ± 0.65 (range 1-5 injections). Factors associated with non-adherence were unilaterality of the injection (p < 0.001), absence of funding (p = 0.002), higher perceived barriers (p = 0.011), lower perceived benefits (p = 0.015), lower self-efficacy (p = 0.023), and lower perceived susceptibility (p = 0.029). In multivariable logistic regression model, the final goodness of fit with the data of the model was high (χ2/df = 1.81, p < 0.001). CONCLUSIONS: Funding and psychological burden are the main controllable factors for compliance to anti-VEGF therapy in DME. Identifying reasons for non-adherence could contribute to a better outcome.

The Effect of Strabismus Muscle Surgery on Corneal Biomechanics.

PURPOSE: Studying the early effect of different extraocular muscle (EOM) surgeries on corneal biomechanics. SUBJECTS AND METHODS: This is a prospective, nonrandomized, interventional study, in which 42 eyes of 29 candidates for EOM surgery for strabismus correction at Cairo university hospitals, aged 14-37 years, were recruited. All participants had measuring of the visual acuity, refraction (spherical equivalent (SE)), assessment of the EOM motility and muscle balance, sensory evaluation, fundus examination, and assessing the ocular biomechanics using the Ocular response analyzer (ORA, Reichert, INC., Depew, NY) noting the corneal hysteresis (CH) and corneal resistance factor (CRF) preoperatively. Same patients were reassessed using ORA 4 weeks postoperatively following a different standard EOM surgery (recti weakening/strengthening and inferior oblique weakening either (graded recession) according to the surgical indication, and ∆CH and ∆CRF were calculated, each is the preoperative - the postoperative value. RESULTS: ∆CH and ∆CRF = -0.78 ± 1.56 and -0.72 ± 2.15, respectively, and a highly significant difference was found between each of the pre- and postoperative CH and CRF (p < 0.001). 18 eyes had single EOM surgery, while 24 had multiple (2 or 3) EOM surgery; ∆CH in the single group = -1.28 ± 1.5, and ∆CH in the multiple group = 0.4 ± 1.49 (p=0.07). 23 eyes had EOM weakening surgery, while 18 had combined weakening and strengthening EOM surgery: ∆CH in the weakening group = -1.24 ± 1.77 and ∆CH in combined group = -0.26 ± 1.07 (p=0.04). A nonsignificant difference was found for ∆CRF (p=0.53). CONCLUSION: A different EOM surgery has an early tendency for increase of the postoperative CH specially for muscle weakening procedures (recti recession/inferior oblique muscle weakening).

Vision-Threatening Behcet's Disease: Severity of Ocular Involvement Predictors.

PURPOSE: To examine and spot systemic findings commonly associated with a serious form of ocular Behcet's disease. This could potentially help ophthalmologists categorize their patients based on future risk and plan treatment accordingly. SUBJECTS AND METHODS: The data of 249 patients with Behcet's disease were examined thoroughly. Correlations between systemic and ocular findings were recorded. Patients were further subgrouped by the authors as having a vision-threatening form of the disease or not. Regression analysis was done to spot predictors for a vision-threatening form of the disease. RESULTS: The presence of systemic vasculitis and oral and genital ulcers in a patient with Behcet's disease was found to be associated with a milder form of ocular affection or none at all and vice versa. Certain correlations between findings were also found. CONCLUSION: Certain findings in Behcet's disease may act as predictors for the severity of ocular affection. Directing our attention to these factors by the internist and ophthalmologist can help plan the frequency of follow-up as well as the aggressiveness of treatment in patients with Behcet's disease.

A Controlled Study on the Correlation between Tear Film Volume and Tear Film Stability in Diabetic Patients.

Purpose. To assess the tear film quantity and correlate it with the quality and stability of the tear film in diabetics and compare them to age matched controls. Introduction. Diabetes affects tear film parameters in multiple ways. Poor metabolic control and neuropathy are postulated factors. To further understand how diabetes affects tear film parameters this study was conducted. Subjects and Methods. Tear meniscus height was measured by anterior segment OCT, along with tear thinning time, a subtype of noninvasive tear break-up time, and blinking rate per minute which were all recorded for 22 diabetic patients. Correlations between these tear film parameters were studied and then compared to 16 age matched controls. Results. A statistically significant difference was found in blinking rate between the diabetic and the control group (P = 0.002), with higher blinking rate among diabetics. All tear film parameters were negatively correlated with duration of diabetes. A positive correlation was found between tear film volume and stability. Conclusion. Diabetes affects the tear film in various ways. Diabetics should be examined for dry eye signs even in absence of symptoms which may be masked by associated neuropathy. Duration of diabetes has an impact on tear film status.

Examining Delay Intervals in the Diagnosis and Treatment of Primary Open Angle Glaucoma in an Egyptian Population and Its Impact on Lifestyle.

Purpose. To examine causes as well as extent of delay in diagnosis and treatment of primary open angle glaucoma patients in a sample of Egyptians. Patients and Methods. 440 patients with primary open angle glaucoma were interviewed to evaluate delay in their diagnosis and treatment. The extent and cause of delay were investigated. The total delay interval, if any, was correlated with socioeconomic and other factors. Results. The median total delay was one year, with 50% of patients having a total delay of 1 year or less, of which 25% exhibited zero total delay. 25% of patients had a delay ranging from 1 to 3 years, and 25% had a total delay ranging from 3 to 27 years. Diagnostic delay accounted for 43.03% of cases. Longer delays were met in patients with certain socioeconomic factors. Patients with a positive family history of glaucoma displayed shorter delay periods. Conclusion. Significant delay in the diagnosis and treatment of glaucoma was found. Poor socioeconomic status seems to hinder timely diagnosis and treatment of POAG. Certain socioeconomic factors seem to correlate with the extent of delay. More effort is thus needed to subsidize the cost of investigations and treatment for glaucoma patients.

Analysis of Factors Affecting Patients' Compliance to Topical Antiglaucoma Medications in Egypt as a Developing Country Model.

Purpose. To study factors affecting patients' compliance to antiglaucoma medications in Egypt where there are unique factors as a developing country. Patients and Methods. A cross-sectional descriptive study on 440 Egyptian patients with open angle glaucoma (OAG) recruited for over two years. The patients were thoroughly interviewed about their age, education level, duration of glaucoma, difficulty in instilling the drops, medication regimens, a family history of glaucoma, knowledge of the disease, and the presence of medical insurance. Results. 236 (53.6%) were noncompliant compared to 204 (46.4%) who were compliant. Females had a tendency for higher compliance (p=0.061). Patient age above 50 years and low level of education and negative family history of glaucoma were factors significantly associated with poor compliance (p < 0.0001). Polytherapy and lack of medical insurance could be contributing factors. Conclusion. Egyptian patients have a high rate of noncompliance compared to the average in literature. Great effort is needed in educating patients about the importance of medications and the risk and the prognosis of this disease. Economic factors must also be taken into consideration in developing countries with large number of poor patients. We recommend simplifying drug regimens, incorporating electronic dose monitors, and creating reminders for follow-up visits of glaucoma patients.

Effect of intracameral bevacizumab injection on corneal endothelial cells: an in vivo evaluation.

BACKGROUND: We studied the effect of an intracameral bevacizumab injection on the corneal endothelium and iris neovessels (INV). METHODS: Ten eyes were studied in 10 patients with an average age of 52.1 +/- 13.17 years. Patients underwent intracameral bevacizumab injections at a concentration of 1.25 mg/0.05 mL. Intraocular pressure, best-corrected visual acuity, gonioscopy, neovascular membrane extent, anterior segment photography, iris fluorescein angiography, pachymetry, and specular microscopy were recorded preoperatively and postoperatively. RESULTS: The minimum follow-up period was 4 months. INVs started to regress within the first 2 days after the injection and regressed completely by the end of the fourth week. Reduction in INV leakage started 1 week after injection, and resolved in 8 eyes (80%) by the end of the fourth week. Intraocular pressure dropped significantly from 17.8 +/- 4.8 mmHg to 16.6 +/- 2.8 mmHg over 4 weeks. The mean endothelial cell loss was 3.95% +/- 6.78%. CONCLUSIONS: An intracameral bevacizumab injection proved to be safe for corneal endothelial cells.