Journal of Ophthalmic and Vision Research
Volume:10 Issue: 1, Jan-Mar 2015

To compare ultrasound pachymetry and Orbscan II for measurement of central corneal thickness (CCT) in normal eyes. The current study was performed at Labbafinejad Medical Center (LMC), Tehran, Iran. Three hundred eyes from 150 healthy individuals referred for keratorefractive surgery were assessed first by Orbscan II and then by ultrasound pachymetry, and CCT values were recorded and compared. Overall, Orbscan II overestimated CCT as compared to ultrasound pachymetry by about 2.4% (mean values 547.6 ± 34.7 versus 534.8 ± 34.7, respectively, P < 0.001). The difference was more significant when CCT was less than 500 microns (mean values 493.2 ± 16.9 versus 479.9 ± 15.6, mean overestimation: 2.6%, P < 0.001). There was good linear correlation between the two methods (Pearson's correlation r = 0.968, P < 0.0001). Orbscan II has good correlation with ultrasound pachymetry for measurement of CCT in normal eyes; however Orbscan II should not be used to evaluate corneal thickness before keratorefractive surgeries, as it tends to overestimate corneal thickness and may result in undesirable, low residual stromal thickness.

To determine the sensitivity and specificity of anterior and posterior corneal elevation parameters as determined by Orbscan II (Bausch and Lomb, Rochester, NY, USA) in discriminating between (sub) clinical keratoconus (KCN) and normal corneas. This prospective case‑control study included 28 eyes with subclinical KCN, 65 with clinical KCN and 141 normal corneas. Anterior and posterior corneal elevation was measured and compared in the central 5‑mm corneal zone using Orbscan II. Receiver operating curves (ROC) curve analyses for posterior corneal elevation showed predictive accuracy in both KCN and subclinical KCN with an area under the curve (AUC) of 0.97 and 0.69, respectively while optimal cutoff points were 51 μm for KCN and 35 μm for subclinical KCN. These values were associated with sensitivity and specificity of 89.23% and 98.58%, respectively, for KCN; and 50.00% and 88.65% for subclinical KCN. ROC curve analyses for anterior corneal elevation showed predictive accuracy in both KCN and subclinical KCN with AUC of 0.97 and 0.69, respectively while optimal cutoff points were 19 μm for KCN and 16 μm for subclinical KCN. These values were associated with sensitivity and specificity of 93.85% and 97.16%, respectively, for KCN; and 60.71% and 87.94% for subclinical KCN. Anterior and posterior corneal elevation data obtained by Orbscan II can well discriminate between KCN and normal corneas, however the reliability of their indices is lower in differentiating subclinical KCN from normal cases.

To evaluate the efficacy of corneal collagen cross‑linking (CXL) for treatment of corneal ulcers not responding to antimicrobial therapy. Eight patients with corneal ulcers associated with corneal melting, not responding to conventional antibiotic therapy, were treated with CXL. The procedure was performed according to the standardized protocol for keratoconus. Preoperative medications were continued after CXL in all cases. Microbiological exams revealed Pseudomonas aeruginosa in 3 cases. Follow up continued from 1 to 10 months. In 6 of 8 eyes, progression of corneal melting was halted and complete epithelialization occurred. In one eye emergency keratoplasty was needed due to corneal perforation. A conjunctival flap was performed to treat severe localized corneal thinning in one of the patients a few days after CXL. Significant clinical improvement occurred in all cases of Pseudomonas aeruginosa keratitis. CXL can be considered as a promising new treatment in the management of refractory non‑healing corneal ulcers, including Pseudomonas aeruginosa keratitis.

To evaluate the effectiveness of topical cyclosporine A 0.05% for treatment of mustard gas‑induced ocular surface disorders with special attention to conjunctival goblet cell density in patients with severe dry eye. This prospective clinical study included 20 eyes of 20 patients previously exposed to mustard gas with dry eye syndrome unresponsive to artificial tears. Before and after treatment with topical cyclosporine A 0.05% twice daily for 3 months, subjects were evaluated for improvement in symptoms using the ocular surface disease index (OSDI) and signs by tear breakup time (TBUT), Schirmer test and measurement of superior bulbar conjunctival goblet cell density. Limbal stem cell deficiency (LSCD) and the degree of corneal squamous cell metaplasia were also assessed before and after treatment. Before treatment, mean OSDI score, Schirmer test I value and mean TBUT were 42.8 ± 6.1, 4.2 ± 1.2 mm and 2.5 ± 1.3 s, respectively. After 3 months of treatment with topical cyclosporine A, these scores reached 36.4 ± 5.2, 5.8 ± 1.6 mm and 4.9 ± 2.1 s, respectively showing a statistically significant improvement (P < 0.001) in all parameters. Mean goblet cell density was 23.3 ± 1. /high power field (hpf) at baseline which was significantly increased to 47.7 ± 16.1/hpf at the end of the study (P < 0.001). There was no improvement, however, in corneal conjunctivalization, LSCD and the degree of corneal squamous cell metaplasia based on impression cytology reports (P > 0.05). Treatment with topical cyclosporine A 0.05% in patients with severe dry eye due to mustard gas injury increases goblet cell density in the bulbar conjunctiva and improves symptoms of the disease.

To evaluate the anterior keratoprosthesis‑cornea interface in eyes with Boston type I keratoprosthesis (Kpro). In a prospective non‑interventional study, patients with Boston type I Kpro underwent ultra‑high resolution optical coherence tomography (UHR‑OCT) evaluation. The images were used to measure and describe characteristics of the anterior keratoprosthesis‑cornea interface, epithelial interaction at the keratoprosthesis edge and the keratoprosthesis‑cornea interface gap. Ten patients including 4 male and 6 female subjects with different preoperative diagnoses, i.e. 8 multiple corneal graft failures and 2 immunological ocular surface diseases, were studied. Mean age was 62.1 ± 20.0 (range, 33.0‑83.0) years and mean interval between surgery and UHR‑OCT evaluation was 15.2 ± 11.09 months. In eight patients, 360° epithelial growth over the peripheral edge of the Kpro was documented. We detected keratoprosthesis‑cornea interface gap in three patients. One subject had developed postoperative endophthalmitis 8 months after surgery and the other two cases were among the high risk group according to the preoperative diagnosis. In one patient with severe ocular hypotony, the Kpro edge was inserted into the anterior stroma and covered with epithelium. UHR‑OCT showed that corneal epithelium covers the Kpro edge and seals the potential space between the Kpro and cornea in 80% of cases. The presence of a gap in the interface and lack of epithelial sealing around the Kpro edge might be associated with endophthalmitis.

To describe prophylactic patterns employed against endophthalmitis after cataract surgery in Iran. This cross-sectional study included 486 ophthalmologists filling in a self‑administered questionnaire during the 20th Annual Congress of the Iranian Society of Ophthalmology in December 2010, Tehran, working in both private and academic medical centers. Prophylactic measures used preoperatively, intraoperatively and postoperatively and self‑reported rates of endophthalmitis were assessed as the main outcome measurements. In the preoperative phase, 75.5% of surgeons used povidone‑iodine in the conjunctival sac and 71.4% of them did not use antibiotics. The rate of intraoperative prophylaxis was 61.9% either in the form of intracameral antibiotics or subconjunctival injection (mostly cephazolin or gentamicin). Only 7.8% of participants used intracameral cephalosporins. Postoperative antibiotics [mostly chloramphenicol (57%) and ciprofloxacin (28%)] were used by 94.2% of surgeons. On average, ten years of practice were required to observe one case of endophthalmitis. The surgeons in present setting used various prophylactic regimens against endophthalmitis after cataract surgery. Setting a local and evidence‑based clinical practice guideline seems necessary.

To study factors affecting laser energy levels required for neodymium: yttrium aluminium garnet (Nd: YAG) laser capsulotomy and to evaluate whether any correlation exists between applied laser energy levels and complications. The present study examined 474 consecutive patients for a number of factors including age, type of posterior capsule opacification (PCO), material and fixation of intraocular lens (IOL) and complication rates, versus energy levels used for Nd: YAG laser capsulotomy. Mean patient age was 55.6 ± 8.7 years and mean follow up period was 22.9 ± 4.5 months. IOL biomaterial (KW ANOVA; P = 0.173) and patient’s age (P = 0.246) did not significantly influence total laser energy requirement for capsulotomy. However, total laser energy levels were significantly higher (KW ANOVA; P < 0.001) with fibro‑membranous and fibrous subtypes of PCO. Complications such as IOL pitting, intraocular pressure (IOP) elevation, uveitis, retinal detachment (RD) and cystoid macular edema (CME) were significantly more common when higher energy levels was used. The mean total energy in patients with RD was 77.7 ± 17.7 mJ as compared to 43.4 ± 26.9 mJ in the rest of the cohort. RD was more common in patients with higher axial length [n = 7 (63%)] (P < 0.001). Type of PCO significantly influenced laser energy levels required for capsulotomy, whereas IOL biomaterial and fixation did not. Complications such as IOL pitting, uveitis, IOP elevation, RD and CME was significantly more common when total laser energy was higher. It is recommended that the lowest possible single pulse laser energy be used for capsulotomy to minimize complications.

To determine the agreement between intraocular pressure (IOP) measurements using an automated non‑contact tonometer (NCT), Goldmann applanation tonometer (GAT), and the ocular response analyzer (ORA) in subjects with primary congenital glaucoma (PCG). Twenty‑nine eyes of 17 PCG patients underwent IOP measurements using NCT, GAT and ORA. Variables obtained by the ORA were corneal‑compensated IOP (IOPcc), Goldmann‑correlated IOP (IOPg), corneal hysteresis (CH), and corneal resistance factor (CRF). A difference more than 1.5 mmHg for IOP was considered as clinically relevant. Mean age of the patients was 12 years. Mean IOP (±standard deviation, SD) was 15.3 ± 2.8 mmHg (GAT), 15.5 ± 6.0 (NCT), 19.2 ± 7.0 (IOPg), and 21.1 ± 7.9 (IOPcc); (P = 0.001). Except for NCT vs. GAT (P = 1.0), the average IOP difference between each pair of measurements was clinically relevant. The 95% limits of agreements were − 10.2 to 10.3 mmHg (NCT vs. GAT), −7. to 15.3 (IOPg vs. GAT), and − 8.1 to 19.0 (IOPcc vs. GAT). The differences in IOP measurements increased significantly with higher average IOP values (r = 0.715, P = 0.001, for NCT vs. GAT; r = 0.802, P < 0.00, for IOPg vs. GAT; and r = 0.806, P < 0.001, for IOPcc vs. GAT). CH showed a significant association with differences in IOP measurements only for IOPcc vs. GAT (r = 0.830, P < 0.001). Mean IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.

To assess changes in aqueous humor levels of different interleukins (IL), tumor necrosis factor (TNF)‑α and vascular endothelial growth factor (VEGF) in patients with uveitis treated with adalimumab. In this study, 24 aqueous humor samples including 12 pre‑ and post‑treatment samples from 6 patients with uveitis treated with subcutaneous adalimumab and 12 samples from patients with cataracts (serving as controls) were evaluated. The levels of IL‑1β, IL‑2, IL‑6, IL‑10, TNF‑α and VEGF were measured using a Luminex® 200™ flow cytometer (Merckmillipore, Merck KGaA, Darmstadt, Alemania) and a highly sensitive ELISA system. The levels of IL‑1β, IL‑2, IL‑6 and IL‑10 in the aqueous humor before and after treatment with adalimumab did not show significant differences. Aqueous VEGF levels significantly reduced after treatment with adalimumab (P = 0.028). Aqueous TNF‑α levels did not significantly change after treatment with adalimumab, however the post‑treatment level was significantly higher in patients as compared to control subjects (P = 0.032). IL‑2 showed significantly higher levels in uveitis patients before treatment as compared to controls (P = 0.024), while its post‑treatment levels were almost normalized. Decrease in the aqueous humor levels of VEGF and IL‑2 after treatment with systemic adalimumab indicates that anti‑TNF‑α therapy induces modifications of some inflammatory mediators involved in the pathogenesis of uveitis. Aqueous humor samples may be useful to assess the effect of adalimumab on intraocular inflammation through measurement of cytokines.

To compare the results of narrow encircling band surgery with standard encircling scleral buckling for retinal detachments (RDs) with intrabasal or unseen breaks. In a retrospective study, eyes with intrabasal or unseen breaks underwent narrow band implantation (group N) or standard encircling buckling plus wide tire placement (group W) and were followed for at least one year. A total of 112 eyes including 39 eyes in group N and 73 eyes in group W were studied. Preoperatively visual acuity of eyes in group N was significantly better (1.55 ± 0.9 vs. 1.93 ± 0.9 logMAR, P = 0.043). The two study groups (N and W) were comparable in terms of the extent of RD (2.8 ± 0.96 vs. 2.8 ± 0.93 quadrants), interval to surgery (88.3 ± 176.4 vs. 71.9 ± 135.4 days) and percentage of visible breaks (56.4% vs. 63%), respectively (all P values > 0.05). More atrophic holes were present in group W and more dialyses were reported in group N. The single operation success rate at 12 months was 69.2% in group N and 74% in group W (P = 0.1). The single operation success rate for eyes with unseen breaks was also comparable (66.7% vs. 85.7%, P = 0.157). Final corrected visual acuity was also similar (0.63 ± 0.44 vs. 0.85 ± 0.69 log MAR). The only factor influencing success rate was the type of retinal breaks (P = 0.04). Type of scleral buckling did not affect the single operation success rate (P = 0.460). Narrow encircling band surgery is a possible option with acceptable single operation success rate for RDs with intrabasal or unseen breaks.

Cytochrome P450 1B1 (Cyp1b1) belongs to the CYP450 superfamily of heme‑binding mono‑oxygenases which catalyze oxidation of various endogenous and exogenous substrates. The expression of Cyp1b1 plays an important role in the modulation of development and functions of the trabecular meshwork (TM). Mutations in Cyp1b1 have been reported in patients with primary congenital glaucoma (PCG). Mice lacking Cyp1b1 also exhibit developmental defects in the TM similar to those reported in congenital glaucoma patients. However, how Cyp1b1 deficiency contributes to TM dysgenesis remains unknown. In the present review, we will address the significance of Cyp1b1 expression and/or its function in anterior segment development. Cyp1b1‑deficient (Cyp1b1−/−) mice are discussed as a promising model for an oxidative stress‑induced model of PCG, in which Cyp1b1 activity is revealed as an important modulator of oxidative homeostasis contributing to the development and structural function of the TM. This conclusion suggests a possible clinical intervention for individuals who are genetically at high risk of developing PCG.

Epidemiologic and genetic/molecular research on glaucoma in Iran started within the past decade. A population‑based study on the epidemiology of glaucoma in Yazd, a city in central Iran, revealed that 4.4% of studied individuals were affected with glaucoma: 1.6% with high tension primary open angle glaucoma (POAG), 1.6% with normal tension POAG, and 0.4% each with primary angle closure glaucoma (PACG) and pseudoexfoliation glaucoma (PEXG), and other types of secondary glaucoma. Two notable observations were the relatively high frequency of normal tension glaucoma cases (1.6%) and the large fraction of glaucoma affected individuals (nearly 90%) who were unaware of their condition. The first and most subsequent genetic studies on glaucoma in Iran were focused on primary congenital glaucoma (PCG) showing that cytochrome P450 1B1 (CYP1B1) is the cause of PCG in the majority of Iranian patients, many different CYP1B1 mutations are present among Iranian patients but only four mutations constitute the vast majority, and the origins of most mutations in the Iranians are identical by descent (IBD) with the same mutations in other populations. Furthermore, most of the PCG patients are from the northern and northwestern provinces of Iran. A statistically significant male predominance of PCG was observed only among patients without CYP1B1 mutations. Clinical investigations on family members of PCG patients revealed that CYP1B1 mutations exhibit variable expressivity, but almost complete penetrance. A great number of individuals harboring CYP1B1 mutations become affected with juvenile onset POAG. Screening of JOAG patients showed that an approximately equal fraction of the patients harbor CY 1B1 and (myocilin) MYOC mutations; MYOC is a well‑known adult onset glaucoma causing gene. Presence of CYP1B1 mutations in JOAG patients suggests that in some cases, the two conditions may share a common etiology. Further genetic analysis of Iranian PCG patients led to identification of Latent‑transforming growth factor beta‑binding protein 2 (LTBP2) as a causative gene for both PCG and several diseases which are often accompanied by glaucomatous presentations, such as Weill‑Marchesani syndrome 3 (WMS3). The findings on LTBP2 have contributed to recognize the importance of the extracellular matrix in pathways leading to glaucoma.

This article discusses corneal cross-linking (CXL) and how it transitioned from a modalityfor treating corneal ectatic disorders to an inventive means of treating infectious keratitis. Initially, CXL was successfully developed to halt the progression of ectatic diseases such as keratoconus, using the standard Dresden protocol. Later, indications were extended to treat iatrogenic ectasia developing after laser-assisted in situ keratomileusis (LASIK) and photo-refractive keratectomy (PRK). At the time, it had been postulated that the combination of ultraviolet light with riboflavin could not only biomechanically strengthen the cornea but also was capable of destroying living cells and organisms including keratocytes and pathogens. Thus a new and innovative concept of treatment for infectious keratitis emerged through the use of CXL technology. Initially only advanced infectious melting ulcers resisting standard microbicidal therapy were treated with CXL in addition to standard therapy. In subsequent studies CXL was also used to treat bacterial keratitis as first line therapy without the use of concomitant antibiotic therapy. With the increasing interest in CXL technology to treat infectious keratitis and to clearly separate its use from the treatment of ectatic disorders, a new term was adopted at the 9th CXL congress in Dublin for this specific indication: PACK-CXL (photoactivated chromophore for infectious keratitis). PACK-CXL has the potential to eventually become an interesting alternative to standard antibiotic therapy in treating infectious corneal disorders, and may help reduce the global burden of microbial resistance to antibiotics and other therapeutic agents.

To report a case of complex Descemet’s membrane detachment (DMD) and tears during phacoemulsification cataract surgery. Case Report: A 64-year-old woman underwent phacoemulsification surgery in her right eye and developed tears and partial loss of Descemet’s membrane (DM) while the aspiration port was inserted through themain incision. Massive corneal edema obscured the view and the anterior chamber was barely visible the following day. Scheimpflug imaging was used to complement slit lamp examination in the postoperative period. Frequent topical corticosteroid drops were initiated. After 5 days of treatment, multiple tears and detachment of DM were visible and the anterior chamber was filled with air. After 5 weeks, the cornea regained much of its clarity despite large DM tears and focal loss of DM. Despite partial loss of DM, the corneal edema mostly disappeared after 5 weeks of air bubble injection. Scheimpflug imaging was beneficial in the diagnosis and monitoring of DM tears and detachments.

To report a case of primary acquired melanosis (PAM) successfully treated with combined topical mitomycin C and interferon-α2b.Case Report: A 75-year-old man presented with an extensive unilateral pigmented lesion involving 360° of the bulbar conjunctiva, extending to the fornices and palpebral conjunctiva. Map biopsy confirmed PAM with local atypia. Treatment was initiated with mitomycin C 0.04% eye drops for two courses. Although the lesion markedly responded to the treatment, residual lesions justified further therapy. To avoid ocular surface toxicity induced by excessive mitomycin C exposure, interferon-α2b eye drops were started and continued for 6 months. The pigmented lesion almost completely disappeared and no significant complication or recurrence was observed for 24 months. Combination therapy using mitomycin C and interferon-α2b for PAM with atypia may be recommended as an effective treatment modality, avoiding the ocular surface toxicity due to excessive mitomycin C exposure.

We describe an innovative technique for performing standardized low cost glaucoma filtration surgery using a polytetrafluoroethylene (PTFE) intravenous cannula. The trocar of a 24 gauge (24G) PTFE intravenous cannula was used to create a trabeculectomy ostium and its tube was inserted under a partial thickness scleral flap in 2 patients with advanced glaucomatous optic neuropathy, in whom intraocular pressure (IOP) was not controlled on maximal tolerable hypotensive therapy. Postoperatively, IOP of the operated eyes at 3, 6 and 9 month's follow-up ranged from 12 to 15 mmHg with a well formed anterior chamber and a diffuse bleb.