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REVIEW ARTICLES
Optical coherence tomography angiography in retinal diseases
KV Chalam, Kumar Sambhav
January-March 2016, 11(1):84-92
DOI:10.4103/2008-322X.180709  PMID:27195091
Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA) algorithm (a vital component of OCTA software) helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD), retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV) in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA). Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.
  32 2,090 565
PERSPECTIVE
PACK-CXL: Corneal cross-linking for treatment of infectious keratitis
David Tabibian, Olivier Richoz, Farhad Hafezi
January-March 2015, 10(1):77-80
DOI:10.4103/2008-322X.156122  PMID:26005557
This article discusses corneal cross-linking (CXL) and how it transitioned from a modality for 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 9 th 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.
  10 989 214
ORIGINAL ARTICLES
Prevalence of refractive errors in students with and without color vision deficiency
Hadi Ostadimoghaddam, Abbas Ali Yekta, Javad Heravian, Abbas Azimi, Seyed Mahdi Ahmadi Hosseini, Sakineh Vatandoust, Fatemeh Sharifi, Fereshteh Abolbashari
October-December 2014, 9(4):484-486
DOI:10.4103/2008-322X.150828  PMID:25709775
Purpose: To evaluate refractive errors in school age children with color vision deficiency (CVD) and those with normal color vision (NCV) in order to make a better understanding of the emmetropization process. Methods: A total of 4,400 primary school students aged 7-12 years were screened for color vision using Ishihara pseudoisochromatic color vision plate sets. Of these, 160 (3.6%) students had CVD. A total of 400 age- and sex-matched students with NCV were selected as controls. Refractive status was evaluated using objective cyclorefraction. Results: The CVD group included 136 male (85%) and 24 female (15%) subjects with mean age of 10.1 ± 1.8 years. The NCV group comprised of 336 male (84%) and 64 female (16%) subjects with mean age of 10.5 ± 1.2 years. The prevalence of myopia (7.7% vs. 13.9%, P < 0.001) and hyperopia (41% vs. 57.4%, P = 0.03) was significantly lower in the CVD group. Furthermore, subjects with CVD subjects demonstrated a lower magnitude of refractive errors as compared to the CVD group (mean refractive error: +0.54 ± 0.19 D versus + 0.74 ± 1.12 D, P < 0.001). Conclusion: Although the lower prevalence of myopia in subjects with CVD group supports the role of longitudinal chromatic aberration in the development of refractive errors; the lower prevalence of hyperopia in this group is an opposing finding. Myopia is a multifactorial disorder and longitudinal chromatic aberration is not the only factor influencing the emmetropization process.
  8 685 160
Long term efficacy of repeat selective laser trabeculoplasty
Albert S Khouri, Hamed B Lari, Tamara L Berezina, Barry Maltzman, Robert D Fechtner
October-December 2014, 9(4):444-448
DOI:10.4103/2008-322X.150814  PMID:25709769
Purpose: To evaluate long term intraocular pressure (IOP) control after repeat selective laser trabeculoplasty (SLT). Methods: This single center study retrospectively reviews the electronic medical records of patients with open angle glaucoma undergoing repeat SLT. Eyes with prior argon laser trabeculoplasty, or incisional surgery before or during the study period were excluded. Demographics, laser parameters, number of glaucoma medications and IOP at baseline and after 1, 4, 8, 12, 18 and 24 months were collected. The percentage of subjects with IOP reduction >20% and ≥15% from baseline was determined. Results: A total of 45 eyes of 25 subjects with mean age of 73 ΁ 9 years undergoing repeat SLT were included. Repeat SLT was performed at a mean interval of 28.3 ΁ 12.7 months after initial treatment. Mean IOP reductions were statistically significant with repeat SLT as compared to baseline at 1, 4, 8, 12, 18 and 24 months' follow-up. Change in IOP after first and repeat SLT were comparable at most time points except at 4, 8 and 12 months when initial treatment had yielded significantly greater reductions. At 24 months, 29% and 39% of eyes achieved IOP reduction >20% and ≥15% respectively after repeat SLT as compared to 36% and 54% of eyes following initial treatment (P > 0.05). Conclusion: Repeat SLT is effective in lowering IOP up to 24 months. Long term IOP control was achieved in 29-39% of eyes following repeat treatment in this cohort of patients.
  7 883 131
Prevalence of amblyopia and refractive errors among primary school children
Zhale Rajavi, Hamideh Sabbaghi, Ahmad Shojaei Baghini, Mehdi Yaseri, Hamidreza Moein, Shadi Akbarian, Narges Behradfar, Simin Hosseini, Hossein Mohammad Rabei, Kourosh Sheibani
October-December 2015, 10(4):408-416
DOI:10.4103/2008-322X.176909  PMID:27051485
Purpose: To determine the prevalence of amblyopia and refractive errors among 7 to 12-year-old primary school children in Tehran, Iran. Methods: This population-based cross-sectional study included 2,410 randomly selected students. Visual acuity was tested using an E-chart on Yang vision tester. Refractive errors were measured by photorefractometry and cycloautorefraction. Strabismus was checked using cover test. Direct ophthalmoscopy was used to assess the anterior segment, lens opacities, red reflex and fundus. Functional amblyopia was defined as best corrected visual acuity ≤20/40 in one or both eyes with no anatomical problems. Results: Amblyopia was present in 2.3% (95% CI: 1.8% to 2.9%) of participants with no difference between the genders. Amblyopic subjects were significantly younger than non-amblyopic children (P=0.004). Overall, 15.9% of hyperopic and 5.9% of myopic cases had amblyopia. The prevalence of hyperopia ≥+2.00D, myopia ≤-0.50D, astigmatism ≥0.75D, and anisometropia (≥1.00D) was 3.5%, 4.9%, 22.6%, and 3.9%, respectively. With increasing age, the prevalence of myopia increased (P<0.001), that of hyperopia decreased (P=0.007), but astigmatism showed no change. Strabismus was found in 2.3% of cases. Strabismus (OR=17.9) and refractive errors, especially anisometropia (OR=12.87) and hyperopia (OR=11.87), were important amblyogenic risk factors. Conclusion: The high prevalence of amblyopia in our subjects in comparison to developed countries reveals the necessity of timely and sensitive screening methods. Due to the high prevalence of amblyopia among children with refractive errors, particularly high hyperopia and anisometropia, provision of glasses should be specifically attended by parents and supported by the Ministry of Health and insurance organizations.
  7 911 222
REVIEW ARTICLES
Cytochrome P450 1B1 and primary congenital glaucoma
Yun Zhao, Christine M Sorenson, Nader Sheibani
January-March 2015, 10(1):60-67
DOI:10.4103/2008-322X.156116  PMID:26005555
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.
  7 1,051 173
REVIEW ARTICLE
Senile dementia and glaucoma: Evidence for a common link
Sachin Jain, Ahmad A Aref
April-June 2015, 10(2):178-183
DOI:10.4103/2008-322X.163766  PMID:26425322
Dementia and glaucoma are both neurodegenerative conditions characterized by neuronal loss leading to cognitive and visual dysfunction, respectively. A variety of evidence exists linking the two diseases including structural signs, specifically degenerative changes within ganglion cells. Both diseases become more prevalent with increased age, but that alone is unlikely to account for the increased co-prevalence of the diseases found in various studies. Neurotoxic substances including abnormal hyperphosphorylated tau and amyloid-β have been found in both disease processes suggesting possible pathophysiologic links between the diseases. The exact mechanism of apoptosis, whether by direct toxicity or potentiation, still needs to be established, but could prove important for both diseases. Another potential link relates to low intracranial pressure in patients with both diseases causing a high translaminar pressure gradient and optic nerve damage in certain patients. While this alone may not account for direct optic nerve damage, it could lead to cerebrospinal fluid (CSF) circulatory failure causing increased neurotoxins along the optic nerves with resultant damage. All of this evidence suggests the need to further study links between the two diseases, as this could prove instrumental in understanding their overlapping pathophysiology and developing directed therapies for both diseases. While this is more thoroughly investigated, it may be prudent to have a lower threshold for a glaucoma work-up in patients with pre-existing dementia.
  6 773 128
REVIEW ARTICLES
Neuroprotection in glaucoma
Azadeh Doozandeh, Shahin Yazdani
April-June 2016, 11(2):209-220
DOI:10.4103/2008-322X.183923  PMID:27413504
Glaucoma is a degenerative optic neuropathy characterized by retinal ganglion cell (RGC) loss and visual field defects. It is known that in some glaucoma patients, death of RGCs continues despite intraocular pressure (IOP) reduction. Neuroprotection in the field of glaucoma is defined as any treatment, independent of IOP reduction, which prevents RGC death. Glutamate antagonists, ginkgo biloba extract, neurotrophic factors, antioxidants, calcium channel blockers, brimonidine, glaucoma medications with blood regulatory effect and nitric oxide synthase inhibitors are among compounds with possible neuroprotective activity in preclinical studies. A few agents (such as brimonidine or memantine) with neuroprotective effects in experimental studies have advanced to clinical trials; however the results of clinical trials for these agents have not been conclusive. Nevertheless, lack of compelling clinical evidence has not prevented the off-label use of some of these compounds in glaucoma practice. Stem cell transplantation has been reported to halt experimental neurodegenerative disease processes in the absence of cell replacement. It has been hypothesized that transplantation of some types of stem cells activates multiple neuroprotective pathways via secretion of various factors. The advantage of this approach is a prolonged and targeted effect. Important concerns in this field include the secretion of unwanted harmful mediators, graft survival issues and tumorigenesis. Neuroprotection in glaucoma, pharmacologically or by stem cell transplantation, is an interesting subject waiting for broad and multidisciplinary collaborative studies to better clarify its role in clinical practice.
  6 1,153 345
Optical coherence tomography angiography of the optic disc; an overview
Handan Akil, Khalil Ghasemi Falavarjani, Srinivas R Sadda, Alfredo A Sadun
January-March 2017, 12(1):98-105
DOI:10.4103/2008-322X.200162  PMID:28299012
Different diseases of the optic disc may be caused by or lead to abnormal vasculature at the optic nerve head. Optical coherence tomography angiography (OCTA) is a novel technology that provides high resolution mapping of the retinal and optic disc vessels. Recent studies have shown the ability of OCTA to visualize vascular abnormalities in different optic neuropathies. In addition, quantified OCTA measurements were found promising for differentiating optic neuropathies from healthy eyes.
  6 509 191
Visual prostheses: The enabling technology to give sight to the blind
Mohammad Hossein Maghami, Amir Masoud Sodagar, Alireza Lashay, Hamid Riazi-Esfahani, Mohammad Riazi-Esfahani
October-December 2014, 9(4):494-505
DOI:10.4103/2008-322X.150830  PMID:25709777
Millions of patients are either slowly losing their vision or are already blind due to retinal degenerative diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) or because of accidents or injuries. Employment of artificial means to treat extreme vision impairment has come closer to reality during the past few decades. Currently, many research groups work towards effective solutions to restore a rudimentary sense of vision to the blind. Aside from the efforts being put on replacing damaged parts of the retina by engineered living tissues or microfabricated photoreceptor arrays, implantable electronic microsystems, referred to as visual prostheses, are also sought as promising solutions to restore vision. From a functional point of view, visual prostheses receive image information from the outside world and deliver them to the natural visual system, enabling the subject to receive a meaningful perception of the image. This paper provides an overview of technical design aspects and clinical test results of visual prostheses, highlights past and recent progress in realizing chronic high-resolution visual implants as well as some technical challenges confronted when trying to enhance the functional quality of such devices.
  6 3,338 294
ORIGINAL ARTICLES
Psychophysical evidence for impaired Magno, Parvo, and Konio-cellular pathways in dyslexic children
Khazar Ahmadi, Hamid Reza Pouretemad, Jahangir Esfandiari, Ahmad Yoonessi, Ali Yoonessi
October-December 2015, 10(4):433-440
DOI:10.4103/2008-322X.176911  PMID:27051489
Purpose: Dyslexia is one of the most common learning disabilities affecting millions of people worldwide. Although exact causes of dyslexia are not well-known, a deficit in the magnocellular pathway may play a role. We examined possible deficiency of magnocellular, as compared to parvocellular and koniocellular pathway function by measuring luminance and color perception. Methods: Visual stimuli consisted of a series of natural images, divided into layers of luminance, red-green and blue-yellow, which probed magnocellular, parvocellular, and koniocellular pathways, respectively. Thirteen children with dyslexia and 13 sex- and age- matched controls performed three psychophysical tasks. In the first task, subjects were instructed to match the contrast of luminance (magno) and red-green (parvo) images to that of the blue-yellow (konio) images. In the second task, subjects detected the isoluminant point of red-green images to probe parvocellular pathway. In the third task, temporal processing was assessed by measuring reaction time and percentage of correct responses in an identification task using four categories of images, activating all three pathways. Results: The dyslexic group had significantly elevated luminance and color contrast thresholds and higher isoluminant point ratio in comparison to the control group. Furthermore, they had significantly less correct responses than the control group for the blue-yellow images. Conclusion: We may suggest that dyslexic subjects might suffer from both magnocellular and parvocellular deficits. Moreover, our results show partial impairment of the koniocellular pathway. Thus, dyslexia might be associated with deficits in all three visual pathways.
  5 609 241
Intravitreal bevacizumab for treatment of central serous chorioretinopathy
Cihan Ünlü, Gurkan Erdogan, Tugba Aydogan, Betul Ilkay Sezgin Akcay, Esra Kardes, Gulunay Akcali Kiray, Tahir Kansu Bozkurt
January-March 2016, 11(1):61-65
DOI:10.4103/2008-322X.180700  PMID:27195087
Purpose: To compare the outcomes of treatment with intravitreal bevacizumab (IVB) versus observation in central serous chorioretinopathy (CSCR). Methods: In a retrospective comparative study, records of 45 patients with CSCR were reviewed. Twenty-two patients received IVB (1.25 mg/0.05 ml) while 23 subjects were observed. All subjects underwent measurement of best corrected visual acuity (BCVA) and intraocular pressure (IOP), dilated fundus examination and optical coherence tomography (OCT) imaging at baseline and follow up visits. Outcome measures included central macular thickness (CMT) and BCVA in logarithm of minimum angle of resolution (logMAR) notations. Results: Mean age was 44.1 ± 9.3 (range: 24 to 64) years and mean follow-up period was 10.4 ± 11.2 (range: 3 to 43; median: 6) months. All patients demonstrated resolution of neurosensory detachment and improvement in visual acuity. At final visit, there was no significant difference in mean CMT between the IVB and observation groups (275 vs 284 μm, P> 0.05). Mean baseline logMAR visual acuity was 0.38 ± 0.24 in the IVB group which improved to 0.24 ± 0.31 at final follow-up (P = 0.011); mean baseline logMAR visual acuity was 0.42 ± 0.28 in the observation group and improved to 0.12 ± 0.18 (P = 0.001). Visual improvement was more marked in the observation group (0.30 vs 0.14 logMAR, P< 0.05) and mean final visual acuity was also significantly better (P = 0.05). Conclusion: There was no significant difference between IVB injection and observation in terms of anatomical outcomes of treatment for CSCR. In terms of visual outcomes, observation was superior to IVB injection.
  5 381 74
Short-term efficacy of intravitreal dexamethasone implant in vitrectomized eyes with recalcitrant diabetic macular edema and prior anti-VEGF therapy
Ankoor R Shah, Mengqiao Xi, Ashkan M Abbey, Yoshihiro Yonekawa, Lisa J Faia, Tarek S Hassan, Alan J Ruby, Jeremy D Wolfe
April-June 2016, 11(2):183-187
DOI:10.4103/2008-322X.183928  PMID:27413499
Purpose: To determine the efficacy of an intravitreal dexamethasone implant (IDI) for diabetic macular edema (DME) in vitrectomized eyes. Methods: This interventional retrospective consecutive case series included vitrectomized eyes undergoing IDI placement for treatment of recalcitrant DME between June 2011 and June 2014. All patients had previously received anti-VEGF therapy (ranibizumab or bevacizumab). Primary endpoints were changes in visual acuity (VA) and central retinal thickness (CRT) from baseline values one month after device implantation. Secondary endpoints were VA and CRT changes at 3 months. Results: A total of 8 eyes of 8 patients met the inclusion criteria. One month after IDI placement, there was a significant (p = 0.01) improvement in VA from 0.79 ± 0.52 logMAR (20/123 Snellen equivalent) to 0.64 ± 0.55 logMAR (20/88), meanwhile CRT improved from 455.75 ± 123.19 to 295.00 ± 90.39 μm (p = 0.02). These findings persisted at 3 months. Conclusion: In vitrectomized eyes previously treated with anti-VEGF agents for recalcitrant DME, implantation of the IDI appears to be efficacious in improving VA and CRT at 1-month with the observed benefits persisting for at least for 3 months.
  5 507 121
Neodymium-yttrium aluminium garnet laser capsulotomy energy levels for posterior capsule opacification
Rahul Bhargava, Prachi Kumar, Hemant Phogat, Kulbhushan Prakash Chaudhary
January-March 2015, 10(1):37-42
DOI:10.4103/2008-322X.156101  PMID:26005551
Purpose: 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. Methods: 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. Results: 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). Conclusion: 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.
  5 840 170
REVIEW ARTICLES
Nutrient supplementation for age-related macular degeneration, cataract, and dry eye
Ronald P Hobbs, Paul S Bernstein
October-December 2014, 9(4):487-493
DOI:10.4103/2008-322X.150829  PMID:25709776
There have been enormous advances in the past decade for the treatment of age-related macular degeneration (AMD); however, these treatments are expensive and require frequent follow-up and injections which place a tremendous burden on both the healthcare system and patients. Consequently, there remains considerable interest in preventing or slowing the progression of AMD requiring treatment. Epidemiological studies have shown that diet is a modifiable AMD risk factor, and nutrient modification is a particularly appealing treatment for AMD due to the perceived universal benefit and relatively low expense. Recently, the age-related eye disease study part two (AREDS2) was concluded and demonstrated further benefit with the addition of lutein and zeaxanthin as a replacement for the β-carotene of the previous generation formulation. The addition of omega-3 essential fatty acids did not show an added benefit. This review aims to highlight some of the evidenced based body of knowledge that has been accumulated from recent studies regarding the use of nutritional supplements and their effect on AMD, cataracts, and dry eyes.
  5 1,914 329
Update on normal tension glaucoma
Jyotiranjan Mallick, Lily Devi, Pradeep K Malik, Jogamaya Mallick
April-June 2016, 11(2):204-208
DOI:10.4103/2008-322X.183914  PMID:27413503
Normal tension glaucoma (NTG) is labelled when typical glaucomatous disc changes, visual field defects and open anterior chamber angles are associated with intraocular pressure (IOP) constantly below 21 mmHg. Chronic low vascular perfusion, Raynaud's phenomenon, migraine, nocturnal systemic hypotension and over-treated systemic hypertension are the main causes of normal tension glaucoma. Goldmann applanation tonometry, gonioscopy, slit lamp biomicroscopy, optical coherence tomography and visual field analysis are the main tools of investigation for the diagnosis of NTG. Management follows the same principles of treatment for other chronic glaucomas: To reduce IOP by a substantial amount, sufficient to prevent disabling visual loss. Treatment is generally aimed to lower IOP by 30% from pre-existing levels to 12-14 mmHg. Betaxolol, brimonidine, prostaglandin analogues, trabeculectomy (in refractory cases), systemic calcium channel blockers (such as nifedipine) and 24-hour monitoring of blood pressure are considered in the management of NTG. The present review summarises risk factors, causes, pathogenesis, diagnosis and management of NTG.
  5 946 314
Surgery for proliferative diabetic retinopathy: New tips and tricks
Patrick Oellers, Tamer H Mahmoud
January-March 2016, 11(1):93-99
DOI:10.4103/2008-322X.180697  PMID:27195092
Over the recent years, retina specialists have enjoyed significant improvements in the surgical management of proliferative diabetic retinopathy including improved preoperative planning, vitreoretinal instrumentation and new surgical maneuvers. In this review, we present new tips and tricks such as preoperative pharmacotherapy approaches including pegaptanib injection and biodegradable dexamethasone implantation, bimanual vitrectomy techniques and the concept of mixing small gauges as well as valved cannulas and intraoperative optical coherence tomography. With advanced surgical planning and sophisticated operative maneuvers tailored to the individual patient, excellent outcomes can be achieved even in severe cases of diabetic tractional detachment.
  5 783 196
ORIGINAL ARTICLES
Topical interferon alpha-2b for treatment of noninvasive ocular surface squamous neoplasia with 360° limbal involvement
Siamak Zarei-Ghanavati, Reza Alizadeh, Sophie X Deng
October-December 2014, 9(4):423-426
DOI:10.4103/2008-322X.150811  PMID:25709765
Purpose: To report the results of topical interferon alpha-2b (IFNα2b) for the treatment of ocular surface squamous neoplasia (OSSN) with 360° limbal involvement. Methods: In a prospective observational study, five patients with biopsy proven primary or recurrent OSSN with 360° limbal involvement received topical IFNα2b (3 million IU/ml, 4 times daily) and were followed from 8 to 12 months. Outcome measures included resolution of the lesion, relief of symptoms, systemic and ocular side effects, and recurrence rate. Results: Five patients including 4 primary OSSNs and one recurrent OSSN received topical interferon alpha-2b. The mean age was 60.2 (range: 52-73) years and mean follow up duration was 10.2 months. Clinical resolution of the tumor occurred in all cases 2 months after initiation of treatment and no patient developed ocular or systemic complications. No recurrence of OSSN developed during the follow up period. Conclusion: Topical recombinant IFNα2b appears to be an effective alternative treatment for OSSN with 360° limbal involvement. This approach precludes the high risk of limbal stem cell deficiency which results from surgical excision or topical chemotherapeutic agents.
  4 622 131
Topical cyclosporine a for treatment of dry eye due to chronic mustard gas injury
Khosrow Jadidi, Yunes Panahi, Ali Ebrahimi, Mostafa Mafi, Farhad Nejat, Amirhossein Sahebkar
October-December 2014, 9(4):417-422
DOI:10.4103/2008-322X.150803  PMID:25709764
Purpose: To evaluate the efficacy of topical cyclosporine A (tCsA) for treatment of dry eye disease in patients suffering from chronic ocular complications of mustard gas (MG) injury. Methods: This interventional case series included patients with MG injury suffering from severe dry eye despite receiving artificial tears and punctal plugs. Patients were administered tCsA 0.05% twice daily for 3 months. Severity of the condition was evaluated by measuring tear osmolarity, ocular surface disease index (OSDI), tear break-up time (TBUT), and Schirmer's test at baseline and at the end of study. Results: A total of 34 patients with chronic MG injury and mean age of 47.1 ± 6.5 years were studied. Compared to baseline values, tear osmolarity (301.7 ± 11.5 vs. 286.3 ± 7.9 mOsmol/L, P < 0.001) and OSDI (47.5 ± 7.2 vs. 42.7 ± 7.1, P < 0.001) were significantly improved. Likewise, Schirmer's test (4.6 ± 1.3 vs. 5 ± 1.3 mm, P < 0.001) and TBUT (1.9 ± 1.4 vs. 2.7 ± 1.5 s, P < 0.001) also significantly recovered at the end of the study. Conclusion: TCsA 0.05% reduces tear osmolarity and improves dry eye symptoms and can serve as an efficacious treatment for ocular complications in patients with chronic MG injury.
  4 1,080 153
Measurement of central corneal thickness using ultrasound pachymetry and Orbscan II in normal eyes
Mohammad Mehdi Sadoughi, Bahram Einollahi, Neda Einollahi, Javad Rezaei, Danial Roshandel, Sepehr Feizi
January-March 2015, 10(1):4-9
DOI:10.4103/2008-322X.156084  PMID:26005545
Purpose: To compare ultrasound pachymetry and Orbscan II for measurement of central corneal thickness (CCT) in normal eyes. Methods: 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. Results: 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). Conclusion: 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.
  4 1,132 206
Multifocal electroretinogram in diabetic macular edema; Correlation with visual acuity and optical coherence tomography
Neda Mazahery Tehrani, Hamid Riazi-Esfahani, Ebrahim Jafarzadehpur, Ali Mirzajani, Hossein Talebi, Abdulrahim Amini, Mehdi Mazloumi, Ramak Roohipoor, Mohammad Riazi-Esfahani
April-June 2015, 10(2):165-171
DOI:10.4103/2008-322X.163773  PMID:26425320
Purpose: To evaluate multifocal electroretinogram (mfERG) changes in eyes with diabetic macular edema (DME) and investigate any possible correlation with optical coherence tomography (OCT) features and visual acuity (VA). Methods: Twenty-nine right eyes of 29 subjects with DME due to non-proliferative diabetic retinopathy and 30 eyes of 30 normal subjects were evaluated. All patients underwent a complete ophthalmic examination. Sixty-one scaled hexagon mfERG responses were recorded. Components of thefirst order kernel of N1, N2, and P1 in five concentric rings centered on the fovea, were measured in both groups. Correlation and regression analyses were performed among VA, central macular thickness (CMT) based on OCT, mfERG amplitude, and latency of the N1, N2 and P1 waves. Results: Significant differences were observed in all mfERG parameters in five-ring regions of the retina between eyes with DME versus controls (P < 0.05). There were significant correlations among VA with N2 (P = 0,001, b = 0.73) and P1 amplitudes (P = 0.001, b = −0.84) in the central macular area, and there was a borderline association between VA and CMT (P = 0.042, b = 0.392). Conclusion: Amplitudes of mfERG components (N1, P1, and N2) are significantly reduced and their latencies are delayed in eyes with DME indicating functional impairment in the outer retina. The mfERG total amplitude was significantly correlated with VA even more than CMT, therefore the combined use of OCT and mfERG for macular evaluation may better evaluate visual status in DME patients.
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REVIEW ARTICLES
Pars planitis: Epidemiology, clinical characteristics, management and visual prognosis
Pinar Cakar Ozdal, Nilufer Berker, Ilknur Tugal-Tutkun
October-December 2015, 10(4):469-480
DOI:10.4103/2008-322X.176897  PMID:27051493
Pars planitis is an idiopathic chronic intermediate uveitis which predominantly affects children and adolescents, and accounts for 5-26.7% of pediatric uveitis. Although an autoimmune process with a genetic predisposition has been suggested, its etiology still remains unknown. The most common presenting symptoms are floaters and blurred vision. Diffuse vitreous cells, haze, snowballs and snowbanks are typical findings of pars planitis. Peripheral retinal vasculitis, optic disc edema and anterior segment inflammation are other well-known findings. Although pars planitis is known to be a benign form of uveitis in most cases, it may become a potentially blinding disease due to complications including cataract, cystoid macular edema, vitreous opacities and optic disc edema. Cystoid macular edema is the most common cause of visual morbidity. Band keratopathy, epiretinal membrane formation, vitreous condensation, neovascularizations, vitreous hemorrhage, retinal detachment, cyclitic membranes, glaucoma and amblyopia may develop as a consequence of the chronic course of the disease. Exclusion of infectious and non-infectious causes which may present with intermediate uveitis is of utmost importance before starting treatment. Treatment of pars planitis has been a controversial issue. There is no consensus specifically for treatment of cases with minimal inflammation and relatively good visual acuity. However, current experience shows that pars planitis may cause severe inflammation and needs an aggressive treatment. A stepladder approach including corticosteroids, immunosupressive agents, anti-tumor necrosis factor-alpha and pars plana vitrectomy and/or laser photocoagulation is the most commonly used method for treatment of pars planitis. Adequate control of inflammation and prompt detection of associated complications are crucial in order to improve the overall prognosis of the disease.
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SURGICAL TECHNIQUE
Modified descemet's stripping automated endothelial keratoplasty for congenital hereditary endothelial dystrophy
Mahmoodreza Panahi-Bazaz, Farideh Sharifipour, Mohammad Malekahmadi
October-December 2014, 9(4):522-525
DOI:10.4103/2008-322X.150836  PMID:25709783
A 19-year-old male with congenital hereditary endothelial dystrophy (CHED) presented with severe bilateral corneal clouding precluding any view of the intraocular structures. He underwent modified Descemet's stripping automated endothelial keratoplasty (DSAEK) technique including a suture pull-through technique to prevent lens damage. Surgery resulted in progressive clearing of the cornea and decreased corneal thickness. Visual acuity increased from hand motions preoperatively to counting fingers at 4 m after 4 months. DSAEK can be successfully performed in phakic eyes with CHED as an alternative to penetrating keratoplasty. It has the advantage of less wound problems and better preservation of globe integrity especially in children.
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ORIGINAL ARTICLES
Aqueous humor levels of different interleukins 1-β, 2, 6 and 10, tumor necrosis factor-α and vascular endothelial growth factor in uveitis treated with adalimumab
María Luisa Hernández Garfella, Paula Palomares Fort, José Andrés Román Ivorra, Enrique Cervera Taulet
January-March 2015, 10(1):49-54
DOI:10.4103/2008-322X.156110  PMID:26005553
Purpose: 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. Methods: 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. Results: 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. Conclusion: 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.
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Intraocular pressure measurement by three different tonometers in primary congenital glaucoma
Athar Zareei, Mohammad Reza Razeghinejad, Mohammad Hosein Nowroozzadeh, Yadollah Mehrabi, Mohammad Aghazadeh-Amiri
January-March 2015, 10(1):43-48
DOI:10.4103/2008-322X.156105  PMID:26005552
Purpose: 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). Methods: 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. Results: 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), −7.8 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 < 0.001, 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). Conclusion: Mean IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.
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* Source: CrossRef