Designing of a pH-Triggered Carbopol®/HPMC In Situ Gel for Ocular Delivery of Dorzolamide HCl: In Vitro, In Vivo, and Ex Vivo Evaluation.

Dorzolamide HCl (DRZ) ophthalmic drop is one of the most common glaucoma medications which rapidly eliminates after instillation leading to short residence time of the drug on cornea. The purpose of the present study is to develop a pH-triggered in situ gel system for ophthalmic delivery of DRZ for treatment of ocular hypertension. In this study, a 32 full factorial design was used for preparation of in situ gel formulations using different levels of Carbopol® and hydroxyl propyl methyl cellulose (HPMC). Rheological behavior, in vitro drug release, ex vivo corneal permeability, and IOP-lowering activity were investigated. DRZ solution (2% w/v) containing of 0.1% (w/v) Carbopol® and 0.1% (w/v) HPMC was selected as the optimal formulation considering its free flow under non-physiological conditions (initial pH and 25 ± 2°C) and transition to appropriate gel form under physiological circumstance (pH 7.4 and 34°C). This in situ gel presented the mucoadhesive property. Ex vivo corneal permeability of this combined solution was similar to those of DRZ solution. The developed formulation compared to the marketed drop (Biosopt®) and DRZ 2% solution had a better performance in intraocular pressure activity. The efficiency and long duration of IOP reduction could be due to the prolonged residence time of the in situ gel. The presence of Carbopol® as a pH triggered and mucoadhesive polymer causes to attach to the ocular mucosal surface for a long term.

Chitosan/carbomer nanoparticles- laden in situ gel for improved ocular delivery of timolol: in vitro, in vivo, and ex vivo study.

Due to the small capacity of the eye cavity and the rapid drainage of liquid into the nasolacrimal duct, patients must frequently administer the drops. Nanoparticles (NPs) and in situ gel systems have each proven their ability to achieve eye retention independently. In this study, timolol-loaded chitosan-carbomer NPs were prepared using the polyelectrolyte complexation method, and incorporated into a pH-responsive in situ gel system made of carbomer. The rheological behavior of NPs-laden in situ gel was examined at room and physiological conditions. Characteristics such as zeta potential, surface tension, refractive index, mucoadhesive properties, drug release, transcorneal permeability, and intra-ocular pressure (IOP) lowering activity were investigated on NPS and NPs-laden in situ gel formulations. The optimum gained NPs system had an encapsulation efficiency of about 69% with a particle size of 196 nm. The zeta potential of the NP and NPs-laden in situ gel were - 16 and + 11 mV respectively. NPs-laden in situ gel presented enhanced viscosity at physiological pH. All physicochemical properties were acceptable for both formulations. NPs and NPs-laden in situ gel systems proved to sustain drug release. They showed mucoadhesive properties which were greater for NPs-laden in situ gel. IOP reduction by NPs-laden in situ gel was significantly higher and more long-lasting than the timolol solution and NPs. In conclusion, the developed NPs-laden in situ gel is a promising carrier for ocular drug delivery due to the slow release of drug from nanoparticles, its mucoadhesive properties, and high viscosity acquisition in contact with precorneal film, which lead to improved therapeutic efficacy.

Analysis of Operated Patients with Ocular Trauma: A 10-Year Retrospective Study.

Background: Ocular trauma is one of the most common causes of hospitalization in patients with ocular injuries. It imposes many direct and indirect physical and psychological costs on the patient and the community. Materials and Methods: The present descriptive cross-sectional and retrospective study includes all patients with ocular trauma who underwent surgery in the referral center's ophthalmic operating room for 10 years. A checklist was completed for each patient, including demographic information and the variables required for the study. A total of 927 patients who underwent eye surgery due to ocular trauma were eligible for the study. All descriptive data were reported as the mean plus standard deviation for quantitative variables and distribution tables and frequency percentage for qualitative variables. Inferential tests such as independent t-test and Chi-square test were used to evaluate the research questions. Results: This study showed that most ocular traumas occur at a young age and mostly in males. The types of trauma in the studied eyes were divided into penetrating and non-penetrating in different age groups. The results showed that the most common type of surgery was corneal laceration repair, and in all patients, visual acuity improved significantly after surgery. In this study, a total of 81% of patients underwent only one operation. Conclusions: Training and caring for children and adolescents about high-risk behaviors and educating industry professionals to wear goggles, and increase workplace safety can reduce these types of trauma.

Absorbable suture for band tightening of scleral buckling in pseudophakic rhegmatogenous retinal detachment: a modified surgical technique and a 6-month follow-up.

Background: Rhegmatogenous retinal detachment (RRD) is a separation of the neurosensory retina from the retinal pigment epithelium as a result of liquid vitreous passing through a retinal break. Scleral buckling surgery (SB) is a conventional treatment for RRD. In SB, a silicon explant is used to indent the sclera, reduce vitreous traction, and close the retinal break, and an encircling band is used circumferentially, leading to myopia. This study aimed to evaluate the functional and biometric outcomes after SB with absorbable band-tightening sutures in patients with pseudophakic RRD. Methods: In this prospective interventional study, we included pseudophakic eyes with RRD treated surgically with SB and a temporary encircling band using a 6-0 absorbable Vicryl suture to tighten the band, instead of conventional permanent suture tightening. Anterior chamber depth (ACD), axial length (AL), intraocular pressure (IOP), spherical equivalent refractive error (SER), and best-corrected distance visual acuity (BCDVA) were measured preoperatively and at 1 day, 2 weeks, 3 months, and 6 months postoperatively. Results: We included 30 eyes of 30 patients with a mean (standard deviation [SD]) age of 66.1 (10.5) years who underwent SB with an absorbable band-tightening suture for pseudophakic RRD. Significant increases in AL and ACD were observed at 2 weeks after surgery, with a significant decline in values thereafter; however, at the 6-month follow-up, the values were significantly higher than those at baseline (all P < 0.05). Based on the Vicryl tension and its hydrolysis, mean (SD) SER at 2 weeks postoperatively was significantly more myopic than at baseline (-5.8 [1.6] D versus +1.3 [1.8] D). However, the mean (SD) SER decreased significantly throughout the 6-month follow-up (all P < 0.05), and it reached -1.8 (0.9) D, which was comparable with the mean baseline SER (P = 0.140). The participants experienced significant improvement in BCDVA throughout the follow-up period (all P < 0.05). Conclusions: Using an absorbable suture to tighten the encircling band in patients with pseudophakic RRD can reduce postoperative myopia without adversely affecting the anatomical or functional outcomes. Future comparative studies with larger sample sizes and longer postoperative follow-up are needed to verify these findings.

The effect of eye care protocol on the prevention of ocular surface disorders in patients admitted to intensive care unit.

Eye care is one of the most critical tasks of intensive care unit (ICU) nurses. Patients in this unit are exposed to potential ocular problems due to critical conditions. This study aimed to establish a new eye care protocol for preventing ocular surface disorders in patients admitted to ICU. This was a clinical trial study performed on patients admitted to ICU in 2019. The data gathering tools included the demographic questionnaire, the Schirmer test for dry eye, fluorescein staining and slit lamp manual for examining corneal ulcers, and slit lamp manual to check keratitis and conjunctivitis. A type of eye care protocol was performed on the patient's eyes. After five consecutive days of executing the protocol, the data were analyzed using SPSS software version 18. The use of eye care protocol reduced the risk of keratitis (P=0.027), conjunctivitis (P=0.012), eye dryness (P=0.001), and corneal ulcer (P=0.003) in patients admitted to ICU in the intervention group compared to the control group. Ophthalmology protocols reduced the incidence of keratitis, conjunctivitis, dry eye, and corneal ulcers in ICU patients. Therefore, using this method in ICU patients can improve nursing care.

Frequency of retinopathy of prematurity at a tertiary referral center.

Background: With advances in medical facilities and increased survival of premature infants, the prevalence of retinopathy of prematurity (ROP) has increased. This study aimed to determine the frequency of ROP and its associated risk factors. Methods: This descriptive-analytical, retrospective study included all premature infants with a birth weight (BW) ≤ 2,500 g and/or gestational age (GA) ≤ 35 weeks who were referred to Imam Khomeini Hospital in Ahvaz, Iran, for ROP screening over a 7-year period from April 2013 to April 2020. Demographic criteria, associated risk factors, and findings of eye examinations were collected and analyzed. Results: Of the 812 at-risk infants screened, 807 met the inclusion criteria. ROP was observed in 316 (39.0%) of the 807 premature infants, with types I and II in 142 (45.0%) and 174 (55.0%) infants, respectively. The mean (SD) GA (29.6 [2.5] weeks versus 30.7 [2.5] weeks) and BW (1,203.6 [382.8] g versus 1,333.5 [386.5] g) were significantly lower in infants with ROP than in those without ROP (both P < 0.001). GA (r = 0.80; P < 0.001) and BW (r = 0.85; P < 0.001) had a strong positive correlation with ROP, and the correlation increased as GA and BW decreased (all P < 0.001). Associated risk factors in infants with ROP, in order of frequency, were oxygen therapy (22.8%), respiratory distress (16.1%), phototherapy (14.6%), blood transfusion (5.7%), apnea (4.1%), mechanical ventilation (1.6%), and intraventricular hemorrhage (0.9%). Multivariate regression analyses showed low GA and BW (both P < 0.05) as independent predictors of ROP. Conclusions: The frequency of ROP in premature infants was slightly higher than the average range reported for domestic and foreign statistics. Low BW and GA were independent predictors of ROP.

Evaluation of changes in corneal volume, volume and angle of anterior chamber in keratoconus patients using Pentacam after CXL.

INTRODUCTION AND OBJECTIVE: Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) is a new technique of mechanical stability of the cornea and prevention of keratoconus progression. The present study aimed at the evaluation of the changes in the corneal volume (CV), volume, and the angle of anterior chamber in keratoconus patients using the Pentacam after CXL. METHODS: This prospective study was performed on 48 eyes of 24 patients (including 12 men, 17-33 years old) with progressive keratoconus undergoing CXL treatment at collagen cross-linking Imam Khomeini Hospital in Ahvaz in 2019. The CV (CV) and anterior chamber parameters such as anterior chamber volume (ACV) and anterior chamber angle (ACA) were measured using the Pentacam before CXL and at 6 and 12 months after CXL. Also, all of the patients were evaluated in terms of best-corrected visual acuity (BCVA), during the follow-up. RESULTS: The pre-CXL values of BCVA was significantly lower than the post-CXL values in 6 and 12 months (0.18 ± 0.11, 0.15 ± 0.10, and 0.11 ± 0.10, respectively, P < 0.0001). In general, there was a significant improvement in the BCVA (P < 0.0001), a significant decrease in the CV (P = 0.001), and a significant increase in the ACV (P < 0.0001), and angle (P < 0.0001) 6 and 12 months after CXL. CONCLUSION: It seems that CXL has a positive effect on the anterior chamber parameters (ACV and ACA) and CV after 6 months and 1 year in the treatment of keratoconus patients. In addition, the visual acuity improves after CXL. Finally, further studies with a higher sample size and longer follow-up periods are recommended.

Anti-microbial Effect and in Vivo Ocular Delivery of Ciprofloxacin-loaded Liposome through Rabbit's Eye.

Purpose: The main purpose of this study was to increase the concentration and bioavailability of Ciprofloxacin (CPX) in the rabbit eye by liposomal formulation. Methods: CPX- loaded liposomes with and without Carbomer 934 (carbomer) were prepared by a thin-layer hydration method. Liposomal formulations after evaluation for characters such as particle size and entrapment efficiency were used in in-vivo experimental for installation into the rabbit's eyes. This experimental study consisted of 10 rabbits divided into two groups. Group 1 (liposomes without coating) and group 2 (carbomer coated liposomes) received one drop per h of liposomes consists of 0.3% CPX in the right eye and commercial CPX eye drop in the left eye until 6 h. Aqueous humor and vitreous samples were collected from all rabbits at the baseline, 1, 3 and 6 h and the drug concentration determined by high pressure liquid chromatography (HPLC). On the other hand, minimum inhibitor concentration (MIC) and minimum bactericidal concentration (MBC) of CPX-loaded in liposomes were determined. Results: liposomal formulations increased ocular bioavailability of CPX around four-folds compared with a commercial CPX eye drop. The increase in the ocular bioavailability may be effective and help to treat bacterial endophthalmitis as well as can be used in prophylaxis of post-operative endophthalmitis. Conclusion: The concentrations of CPX on the aqueous humor and vitreous after liposomes application were more than MIC of CPX against pseudomonas auroginosa and staphylococcus aurous but for commercial eye drop was less than MIC. Therefore liposomes modified the pharmacokinetics of CPX and improved pharmacodynamics property.

Prevention of Corneal Neovascularization; a Preliminary Experimental Study in Rabbits.

The purpose of this study was to compare the effects of propranolol, timolol and bevacizumab with betamethasone to prevent corneal neovascularization (CNV) in rabbits. This study was performed on 28 male rabbits. CNV was induced by three 7-0 silk sutures 2 mm long and 1 mm distal to the limbus. Animals were randomly divided into 4 groups of propranolol + betamethasone, timolol + betamethasone and bevacizumab + betamethasone and betamethasone alone. Eye drops were started from the first day of study. On 7th, 14th, 21st, 28th, 35th and 42nd days, vascular progression, time of neovascularization and vascular area were evaluated and compared with the control group (betamethasone alone). There was a significant reduction in the area of ​​neovascularization in the timolol and bevacizumab groups compared to the control group (P-value = 0.05, P=0.047, respectively). Also, regarding vascular progression, there was a significant decrease in the timolol and bevacizumab groups (P-value = 0.014, P=0.002, respectively). Regarding delayed onset of neovascularization, there was a significant difference in the timolol and bevacizumab group in rabbits (P-value = 0.04, P=0.00, respectively). In conclusion, the use of timolol and bevacizumab drops besides betamethasone can delay neovascularization and decrease the length of corneal vascularization in rabbits.

Comparison of Corneal Epithelial Thickness Map Measured by Spectral Domain Optical Coherence Tomography in Healthy, Subclinical and Early Keratoconus Subjects.

The aim of this study was to compare epithelial thickness map obtained by Spectral Domain Optical Coherence Tomography (SD-OCT) of eyes with myopic astigmatism but without keratoconus, subclinical and early keratoconus. Sixty-three eyes were divided into three groups; myopic astigmatism without keratoconus, subclinical and early keratoconus. Corneal epithelial thickness map was obtained by SD-OCT for all patients and compared between the 3 groups. Mean ± Standard Deviation of epithelial thickness in the area of minimum corneal epithelial thickness, in the one eighth part of the inferior (I) and in the one eighth part of the temporal (T) were 56.64±2.82 µm, 59.00±3.24 µm and 60.40±4.93 µm respectively in subclinical group. Three parameters on epithelial maps obtained by SD-OCT was significantly different in the 2 groups: I and T corneal epithelial thickness map was thicker in subclinical keratoconus (P<0.02 and P<0.02 respectively). Epithelial map uniformity indices were different between the groups, as Superior-I, Superonasal-Inferotemporal were lower (P<0.00 and P< 0.01 respectively) but T-nasal was higher in the subclinical group (P<0.02). The area with minimum epithelial thickness had a significantly lower amount in early keratoconus group compared to the other two groups (P<0.00). In conclusion, corneal epithelial thickness map provided early detection of keratoconus in the subclinical stage with compensatory epithelial thickening of inferior and one eighth of temporal compared to total corneal thickness and changes in epithelial map uniformity indices may lead to early detection of subclinical keratoconus from normal cornea.

Quantitative Analysis of Macular Thickness following Open Globe Injury in Subjects with Clear Media and no Retinal Damage.

PURPOSE: To evaluate the change in macular thickness after open globe injury (OGI) in patients with clear media and without retinal damage using optical coherence tomography (OCT). METHODS: In this longitudinal observational pilot study, 17 patients with clear media and without retinal damage who underwent repair of OGI for corneal, corneoscleral, or scleral laceration were studied. In addition to routine follow-up, all patients were examined at the first and third postoperative months and best corrected visual acuity (BCVA), slit-lamp examination, applanation tonometry, dilated fundus examinations, and macular OCT scans were documented. RESULTS: In all patients, no signs of macular edema, macular thickening, cystic changes, or other signs of cystoid macular edema were present in OCT images and examinations. The Early Treatment Diabetic Retinopathy Study map indicated that there were no significant differences in macular thickness between the first and third months in all patients (P > 0.05). There was no significant relationship between macular thickness and uveal or vitreous prolapse and the size or site of laceration (P > 0.05). BCVA in the first and third months also showed no significant change (P > 0.05). There were no cases of intraocular pressure increase in any of the patients. CONCLUSION: Macular thickness had no significant change following OGI repair in eyes with clear media and without retinal damage; thus, it seems that OGI of this extent and its surgical repair have no effect on macular thickness.

Intravitreal Injection of Anti-vascular Endothelial Growth Factor Agents for Ocular Vascular Diseases: Clinical Practice Guideline.

PURPOSE: To provide the clinical recommendations for the administration of intravitreal anti-vascular endothelial growth factor (VEGF) drugs especially bavacizumab for ocular vascular diseases including diabetic macular edema, neovascular age-related macular degeneration, myopic choroidal neovascularization, retinal vein occlusion and central serous chorioretinopathy. METHODS: Twenty clinical questions were developed by the guideline technical committee. Relevant websites and databases were searched to find out the pertinent clinical practice guidelines to answer the questions. The technical committee provided possible answers (scenarios) according to the available evidences for each question. All scenarios along with their levels of evidence and the supported articles were sent to the experts for external review. If the experts did not agree on any of the scenarios for one particular clinical question, the technical committee reviewed all scenarios and their pertinent evidences and made the necessary decision. After that, the experts were asked to score them again. All confirmed scenarios were gathered as the final recommendations. RESULTS: All the experts agreed on at least one of the scenarios. The technical committee extracted the agreed scenario for each clinical question as the final recommendation. Finally, 56 recommendations were developed for the procedure of intravitreal anti-VEGF injection and their applications in the management of ocular vascular diseases. CONCLUSION: The implementation of this guideline can standardize the management of the common ocular vascular diseases by intravitreal injection of anti-VEGF agents. It can lead to better policy-making and evidence-based clinical decision by ophthalmologists and optimal evidence based eye care for patients.

Serum Vitamin A Levels in Patients with Chalazion.

Chalazion is a chronic, localized lipogranulomatous inflammation of the sebaceous glands of the lids. Chalazion occurs often secondary to blockage of the sebaceous gland ducts. Some studies have reported vitamin A deficiency as a risk factor for chalazion. In this study, we determined the serum levels of vitamin A in patients with chalazion. The study involved a total of 107 subjects (52 patients with chalazion and 55 control healthy subjects). The study was conducted at the Ophthalmology Clinics of Imam Khomeini Hospital, Ahwaz Jundishapur University of Medical Sciences, Ahwaz, Iran between September 2014 and February 2015. The subjects were divided into three groups according to age: 7-12 years old, 13-19 years old, and more than 19 years old. Patients were further divided into four subgroups based on the type of chalazion: single, multiple, primary, and recurrent. Blood samples were collected and the serum was tested for levels of vitamin A using high-performance liquid chromatography (HPLC). The average serum vitamin A levels in patients with chalazion in the age groups of 7-12 and 13-19 years were significantly lower than in their control counterparts. Serum vitamin A levels in patients with recurrent, multiple chalazia were significantly lower than in patients with primary, multiple chalazia (P = 0.026) and patients with a recurrent, single chalazion (P = 0.029). In conclusion, chalazion could be one of the ocular presentations of vitamin A deficiency.

Topical Timolol Inhibits Corneal Neovascularization in Rabbits.

Timolol is a non-selective beta-adrenergic antagonist that is similar to propranolol. The mechanism through which these drugs act on the regression of neovascularization is largely unknown. However, it is thought that the drugs may act through vascular endothelial growth factor signaling, vasoconstriction, and vascular endothelial cell apoptosis. The aim of this study was to determine the effect of timolol on corneal neovascularization in rabbits. Neovascularization was induced in the eyes of 20 rabbits. Next, the rabbits were divided into two groups: the timolol (experimental) group received eye drops containing timolol 0.5% twice per day; and the saline (control) group received saline drops twice per day for two weeks. After 7 days, the mean area of corneal neovascularization (presented as a percentage relative to baseline) was significantly lower in the timolol group than in the saline group (4.63 ± 4.61% versus 58.39 ± 6.31%, P < 0.001). After 2 weeks, the mean area of corneal neovascularization was 0.85 ± 1.33% in the timolol group and 1.73 ± 2.06% in the saline group (P = 0.315). After the first week of treatment, timolol significantly reduced the area of neovascularization compared to control. Timolol may increase the rate of recovery from corneal neovascularization.

Ocular Dorzolamide Nanoliposomes for Prolonged IOP Reduction: in-vitroand in-vivo Evaluation in Rabbits.

Dorzolamide ophthalmic drop is one of the most common glaucoma medications but it has a short residence time in the eye. The aim of this study is to develop ocular dorzolamide HCl nanoliposomes (DRZ - nanoliposomes) and to evaluate their potential use for the treatment of ocular hypertension. Nanoliposomes were prepared using Reverse-phase evaporation vesicle (REV) and thin layer hydration (TLH) method with 7:3 and 7:4 molar ratios of phosphatidylcholine:cholesterol. The physicochemical properties of the formulations were investigated. Formulations with 7:4 lipid ratios were evaluated in terms of drug release, physical stability and ex-vivo permeation through the excised albino rabbit cornea. The rabbits in groups of 6 were treated with selected DRZ - nanoliposomes or dorzolamide solution or marketed dorzolamid preparation (Biosopt®) and intraocular pressure (IOP) was monitored. Formulations with 7:4 molar ratio entrapped greater amount of drug compared to those with 7:3 lipid components ratio. DRZ - nanoliposomes with 7:4 lipid ratio showed more transcorneal permeation than Dorzolamide solution (p<0.05); and the formulation prepared by TLH method exhibited higher permeability than that prepared by REV method (p<0.05). The selected DRZ - nanoliposomes showed greater IOP lowering activity and a more prolonged effect compared to dorzolamide solution and Biosopt®. DRZ - nanoliposomes prepared by TLH method with 7:4 ratios showed promising results as a candidate for the treatment of ocular hypertension.

Diabetic Retinopathy Clinical Practice Guidelines: Customized for Iranian Population.

PURPOSE: To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population. METHODS: Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology [Preferred Practice Pattern 2012], and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefits, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9. RESULTS: Agreed recommendations were accepted as the final recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence. CONCLUSION: This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy.

Effect of adding oral calcium dobesilate to laser photocoagulation on the macular thickness in patients with diabetic macular edema: a randomized clinical trial.

PURPOSE: To evaluate the effect of oral calcium dobesilate (Doxium) on macular thickness in clinically significant macular edema (CSME). METHODS: Overall, 71 eyes of 40 patients with non-proliferative diabetic retinopathy and clinically significant macular edema were included. All patients were received laser treatment for macular edema. Coherence optical tomography was used to determine the retinal thickness. Patients were randomized into two groups: group A received three Doxium capsule daily and group B received three placebo capsule daily for six months. RESULTS: The mean macular thickness before and after treatment in the group A was 340 and 257 micrometers respectively (24.5% reduced), and in the group B was 336 micrometers and 263 micrometers respectively (21.5% reduced). Macular thickness significantly decreased after treatment in both groups and the reduction in group A is higher but the difference of reduction between the two groups was not statistically significant (P>0.05). CONCLUSION: In respect to the effect of adding oral Doxium to Laser Photocoagulation on the macular thickness in patients with diabetic macular edema, this study showed no statistically significant difference between Doxium and placebo.

Pars plana vitrectomy and silicone oil injection in phakic and pseudophakic eyes; corneal endothelial changes.

PURPOSE: To evaluate the effect of silicone oil (SO) on the corneal endothelium in SO filled phakic and pseudophakic vitrectomizied eyes. METHODS: This prospective comparative consecutive case-control study evaluated the corneal endothelial characteristics of 64 SO filled vitrectomizied eyes (case group) as compared to 46 vitrectomizied eyes without SO injection (control group). Endothelial cell densities (ECD), coefficient of variation (CV), and percentage of hexagonal cells (hexagonality) at the corneal center were evaluated preoperatively, 1 month and 6 months after surgery using noncontact specular microscopy and were compared between the two groups. Exclusion criteria were previous vitreoretinal surgery, aphakia, any degree of anterior chamber inflammation, SO bubbles in the anterior chamber and increased intraocular pressure in the postoperative period. RESULTS: Six months after SO injection, mean ECD was 2,438.2±327.6 cell/mm(2) in the case group and 2,462.6±361.7 cell/mm(2) in the control group (P = 0.714) and mean hexagonality was 49.6 ± 6.8 and 54.6 ± 8.9, in the case and control groups, respectively (P = 0.004). Six months after operation, CV in the case group was 39.3 ± 5.6 and that in the control group was 35.7 ± 6.4 (P = 0.003). CONCLUSION: Although the presence of SO in the vitreous cavity of phakic and pseudophakic eyes causes slight reduction in the number of endothelial cells, however it leads to significant changes in endothelial cell morphology. Thus, removal of SO after reaching the desired tamponade effect is recommended.

Comparison of IOPen rebound tonometer with Goldmann applanation tonometer at different IOP levels.

AIM: To compare the accuracy of IOPen rebound tonometer with Goldmann applanation tonometer (GAT) in individuals with low, normal and high intraocular pressure (IOP) and to evaluate the effect of central corneal thickness (CCT) on IOP measurements. METHODS: This cross-sectional study consisted of 159 participants. IOP of one eye of each subject was measured consecutively with IOPen and GAT. Then CCT was measured using an ultrasonic pachymeter. Based on GAT IOP readings, participants were divided into low, normal and high IOP groups. Correlation between tonometers and CCT was calculated by spearman's correlation coefficient. Agreement between tonometers was evaluated using Bland-Altman method. RESULTS: Non-significant underestimation of IOP by IOPen was observed in low IOP group (Mean difference: 0.20mmHg; P=0.454) and also in normal IOP group (Mean difference: 0.56mmHg; P=0.065). However, IOPen significantly overestimated IOP in high IOP group (Mean difference: 1.06mmHg; P=0.038). The 95% limits of agreement (LoA) width between IOPen and GAT IOPs were 7.84, 8.57 and 14.27mmHg in low, normal and high IOP groups, respectively. Low IOP group had thinner corneas compared to high IOP group (P=0.034). IOP measurements taken by IOPen were not influenced by CCT (P=0.099) while poor correlation between CCT and GAT was found (R=0.17, P=0.032). Using receiver operating characteristic (ROC) curve, cutoff value of 18.75mmHg was determined for IOPen with sensitivity of 98.1 and specificity of 97.2%. CONCLUSION: Accuracy of IOPen is comparable to GAT in patients with low or normal IOP but IOPen overestimates IOP at high IOP levels. CCT does not affect IOP readings with IOPen.

Intraretinal foreign bodies: surgical techniques and outcomes.

PURPOSE: To report the clinical features of eyes with intraretinal foreign bodies (IRFBs) and to evaluate the results of surgical management in these eyes. METHODS: Hospital records of 34 eyes of 33 patients with IRFBs were reviewed. All eyes underwent pars plana vitrectomy to remove the foreign bodies using intraocular forceps or by magnetic extraction. RESULTS: All patients were male with mean age of 28±12.3 years and were followed for a mean period of 24.5±2.3 months. The IRFBs were ferromagnetic in 29 (85.3%) cases and were removed using an external magnet in 13 eyes (38.4%) or intraocular forceps in 21 eyes (61.6%). Laser photocoagulation was performed around the IRFB prior to surgery in 7 (20.6%) eyes. Macular pucker and scars developed in 8 (23.5%) eyes and retinal breaks posterior to the sclerotomy were formed in 12 eyes (35.3%) postoperatively. Final visual acuity was 20/40 or better in 12 (35.3%) eyes and 20/200 or better in 23 (67.7%) eyes. Final visual acuity of 20/200 or better had no significant relationship with the site, size, or type of the IRFB or with the interval from trauma to surgery. CONCLUSION: Despite the complexity of surgical management of IRFBs, anatomic and visual outcomes of vitreoretinal surgery in these cases are generally good. The appropriate route of removal may be determined by the type, size, and site of the IRFB. Removal of magnetic IRFBs using external magnets versus intraocular forceps seems to entail comparable results.