Journal of Ophthalmic and Vision Research
Volume:11 Issue: 1, Jan-Mar 2016

To investigate whether microRNA (MIR)‑184 mutations make a substantial contribution to keratoconus (KCN) among affected Iranian patients.
A total of 47 Iranian KCN patients, diagnosed based on family history, clinical examinations using slit lamp biomicroscopy, refraction and corneal topography were enrolled in this study. The pri‑miR‑184 encoding gene obtained from the DNAs of all participants was amplified using polymerase chain reaction and subsequently sequenced by the Sanger dideoxynucleotide protocol. The sequences were compared to MIR184 reference sequence in order to identify sequence variations. The potential effects of a single variation observed on RNA structure was predicted.
Only one sequence variation, � >T, was observed within the pri‑miR‑184 encoding sequence in one proband. The patient’s KCN‑affected sister harbored the same variation. The variation was not novel and was recently shown to be present at similar frequencies among large cohorts of KCN patients and control individuals.
Mutations in MIR‑184 are not a major cause of keratoconus among Iranian patients. The pri‑miR‑184 sequence needs to be screened in larger cohorts in order to establish whether mutations in the gene are present at low frequencies among Iranian patients.

To determine the predictive ability of different data measured by the Galilei dual Scheimpflug analyzer in differentiating subclinical keratoconus and keratoconus from normal corneas.
This prospective comparative study included 136 normal eyes, 23 eyes with subclinical keratoconus, and 51 keratoconic eyes. In each eye, keratometric values, pachymetry, elevation parameters and surface indices were evaluated. Receiver operating characteristic (ROC) curves were calculated and quantified by using the area under the curve (AUC) to compare the sensitivity and specificity of the measured parameters and to identify optimal cutoff points for differenciating subclinical keratoconus and keratoconus from normal corneas. Several model structures including keratometric, pachymetric, elevation parameters and surface indices were analyzed to find the best model for distinguishing subclinical and clinical keratoconus. The data sets were also examined using the non‑parametric “classification and regression tree” (CRT) technique for the three diagnostic groups.
Nearly all measured parameters were strong enough to distinguish keratoconus. However, only the radius of best fit sphere and keratometry readings had an acceptable predictive accuracy to differentiate subclinical keratoconus. Elevation parameters and surface indices were able to differentiate keratoconus from normal corneas in 100% of eyes. Meanwhile, none of the parameter sets could effectively discriminate subclinical keratoconus; a 3‑factor model including keratometric variables, elevation data and surface indices provided the highest predictive ability for this purpose.
Surface indices measured by the Galilei analyzer can effectively differentiate keratoconus from normal corneas. However, a combination of different data is required to distinguish subclinical keratoconus.

To compare the visual outcomes of deep anterior lamellar keratoplasty (DALK) for keratoconus with and without successful big-bubble formation.
In this retrospective comparative study, a total of 289 consecutive eyes from 257 patients underwent DALK using the big-bubble technique. In cases where the big bubble could not be accomplished, manual stromal dissection down to Descemeton membrane (DM) was performed using a crescent knife. Visual acuity and refractive outcomes were compared between the bare DM group (Group 1) and manual dissection group (Group 2).
A bare DM was successfully achieved in 229 (79.2%) eyes and manual dissection was performed in 60 (20.8%) eyes. The study groups were comparable in terms of age (P = 0.79), preoperative best-spectacle corrected visual acuity (BSCVA) (P = 0.15), and follow-up duration (P = 0.73). Postoperative BSCVA was significantly better in Group 1 than in Group 2 throughout follow-up (P Retention of the posterior corneal stroma which occurs with manual dissection during failed big bubble formation in DALK is associated with lower visual acuity as compared to achieving a bare DM.

To evaluate long‑term follow‑up data on implantation of a full‑ring intra‑corneal implant (MyoRing) for management of keratoconus.
A total of 40 keratoconic eyes of 37 consecutive patients who had undergone MyoRing implantation using the Pocket Maker microkeratome (Dioptex, GmbH, Linz, Austria) and completed 3 years of follow‑up appointments were included in this retrospective study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction and keratometry (K) readings were measured and evaluated preoperatively, and 3 years, postoperatively.
No intraoperative complications were observed in this case series. Three years postoperatively, there was a significant improvement in UDVA, CDVA, K readings, spherical equivalent (SE), and manifest sphere and cylinder (P MyoRing implantation using the Pocket Maker microkeratome was found to be a minimally invasive procedure for improving visual acuity and refraction in the majority of the patients with keratoconus.

To compare the visual outcomes of deep anterior lamellar keratoplasty (DALK) for keratoconus with and without successful big‑bubble formation.
In this retrospective comparative study, a total of 289 consecutive eyes from 257 patients underwent DALK using the big‑bubble technique. In cases where the big bubble could not be accomplished, manual stromal dissection down to Descemeton membrane (DM) was performed using a crescent knife. Visual acuity and refractive outcomes were compared between the bare DM group (Group 1) and manual dissection group (Group 2).
A bare DM was successfully achieved in 229 (79.2%) eyes and manual dissection was performed in 60 (20.8%) eyes. The study groups were comparable in terms of age (P = 0.79), preoperative best‑spectacle corrected visual acuity (BSCVA) (P = 0.15), and follow‑up duration (P = 0.73). Postoperative BSCVA was significantly better in Group 1 than in Group 2 throughout follow‑up (P Retention of the posterior corneal stroma which occurs with manual dissection during failed big bubble formation in DALK is associated with lower visual acuity as compared to achieving a bare DM.

To report the anatomical and visual outcomes of double layered amniotic membrane transplantation (AMT) in eyes with advanced Pseudomonas keratitis leading to Descemetocele formation.
This prospective interventional case series included 6 eyes of 6 female patients with pseudomonas keratitis caused by contact lens‑induced infection who underwent double layered AMT. Surgery was performed after the ulcers were found to be poorly responsive to antibiotics, and severe thinning or Descemetocele had developed. All patients underwent a complete examination pre‑ and postoperatively, as well as anterior segment optical coherence tomography (OCT) and pachymetry or Orbscan after the procedure.
Mean follow‑up period was 24 months. There was neither frank corneal perforation nor a need for emergent corneal transplantation in any of the eyes. All patients had visual acuity of hand motions before the procedure which improved to 20/50 to 20/30 three months after surgery. No surgical or postoperative complication occurred in this series.
Double layered AMT may result in acceptable anatomical outcomes in patients with advanced Pseudomonas keratitis with Descemetocele formation and can eliminate the need for emergent corneal transplantation.

To evaluate diurnal variations in intraocular pressure (IOP), central corneal thickness (CCT), and macular and retinal nerve fiber layer (RNFL) thickness in diabetic patients and normal individuals.
This study included 11 diabetic patients with macular edema and 11 healthy individuals. IOP, CCT, and macular and RNFL thickness were measured every 3 hours on a single day between 9 AM and 6 PM. Diurnal variations in IOP, CCT, total macular volume (TMV), central macular thickness (CMT), average macular thickness (AMT), and RNFL thickness were measured.
None of the parameters showed a significant absolute or relative change over the course of the day. However, the following non‑significant changes were observed. In the control group, all parameters demonstrated the highest values at 9 AM. The lowest IOP, TMV and AMT occurred at 12 PM; lowest CCT and RNFL at 6 PM; and the lowest CMT at 3 PM. Diabetic subjects had the highest values of RNFL, CMT and TMV at 9 AM, and that for IOP, CCT and AMT at 6 PM. The lowest RNFL and CMT values occurred at 6 PM; lowest IOP at 12 PM; and the lowest CCT, TMV and AMT were observed at 3 PM. In the diabetic group, TMV, CMT, AMT and CCT were significantly higher and RNFL was significantly lower than the control group at all time points (all P-values While there were slight decreases in IOP, RNFL thickness and CMT during the day, these changes were not significant between 9 AM and 6 PM and probably do not affect the interpretation of measurements.

To determine the clinical features and risk factors of presumed ocular toxoplasmosis (POT) in patients affected with the condition at Irrua, Nigeria.
The study included 69 patients with POT, and 69 age and sex matched subjects who served as the control group. Data was obtained using interviewer administered questionnaires. Examination included measurement of visual acuity (VA), intraocular pressure (IOP), slit lamp examination, gonioscopy and dilated fundus examination.
Mean age of cases and control subjects was 57.16 ± 18.69 and 56.09 ± 16.01 years respectively. The peak age group in patients with POT was 60 years and above. The most common presenting complaint was blurred vision occurring in 100% of cases. Drinking unfiltered water in 58 (84.1%) patients was the most common risk factor. Other risk factors included post cataract surgery status in 32 (46.4%) subjects, ingestion of poorly cooked meat in 30 (43.5%) cases and exposure to cats in 9 (13.0%) patients. All risk factors were more common in POT patients (P Patients with POT were rather old and some risk factors were modifiable, therefore health education for preventing the transmission of toxoplasmosis and provision of sanitary water may help reduce the incidence of ocular toxoplasmosis.

To evaluate the association between age‑related macular degeneration (ARMD) and sensory neural hearing impairment (SHI).
In this case‑control study, hearing status of 46 consecutive patients with ARMD were compared with 46 age‑matched cases without clinical ARMD as a control group. In all patients, retinal involvements were confirmed by clinical examination, fluorescein angiography (FA) and optical coherence tomography (OCT). All participants were examined with an otoscope and underwent audiological tests including pure tone audiometry (PTA), speech reception threshold (SRT), speech discrimination score (SDS), tympanometry, reflex tests and auditory brainstem response (ABR).
A significant (P = 0.009) association was present between ARMD, especially with exudative and choroidal neovascularization (CNV) components, and age‑related hearing impairment primarily involving high frequencies. Patients had higher SRT and lower SDS against anticipated presbycusis than control subjects. Similar results were detected in exudative, CNV and scar patterns supporting an association between late ARMD with SRT and SDS abnormalities. ABR showed significantly prolonged wave I and IV latency times in ARMD (P = 0.034 and 0.022, respectively). Average latency periods for wave I in geographic atrophy (GA) and CNV, and that for wave IV in drusen patterns of ARMD were significantly higher than controls (P = 0.030, 0.007 and 0.050, respectively).
The association between ARMD and age‑related SHI may be attributed to common anatomical components such as melanin in these two sensory organs.

To compare the outcomes of treatment with intravitreal bevacizumab (IVB) versus observation in central serous chorioretinopathy (CSCR).
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.
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 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.

To report the outcomes of half‑dose photodynamic therapy (PDT) in patients with chronic central serous chorioretinopathy (CSC).
A chart review of patients with chronic CSC who had received half‑dose verteporfin PDT (3 mg/m2) was performed. The main outcome measures were resolution of subretinal fluid and best corrected visual acuity (BCVA).
Fifty‑three eyes of 51 patients with mean age of 45.01 ± 8.9 years were studied. Three, 6 and 12 months after half‑dose PDT, subretinal fluid was completely resolved in 51 eyes (96.2%). In 2 eyes (one patient), subretinal fluid decreased at 3 months but one year later, an increase in subretinal fluid was detected on optical coherence tomography (OCT) which completely resolved following additional PDT. Another patient with recurrence of subretinal fluid rejected further treatment. Mean baseline central subfield thickness was 385 ± 113.0 μm which was decreased to 235 ± 39.7, 247 ± 49.7, and 244 ± 49.52 μm after 3, 6 and 12 months, respectively (all P‑values Half‑dose PDT is effective for treatment of patients with chronic CSC.

To characterize histopathologic and electroretinographic (ERG) changes in the retina of pigmented rats injected with sodium iodate in order to establish a model of retinal degeneration for future cell therapy studies.
In 50 male pigmented rats weighing 250‑300 grams, NaIO3 was injected into the left orbital venous plexus at 40 and 60 mg/kg doses (25 eyes in each group). Fourteen rats received phosphate buffered saline (PBS) injection in their left orbital plexus and were considered as the sham‑control group. Histopathologic and ERG studies were performed at baseline and on days 1, 7, 14 and 28 after the injections.
Progressive retinal pigment epithelial (RPE) changes were observed from the first day of injection in both the 40 and 60 mg/kg study groups in a dose dependent manner. These changes manifested as loss of melanin pigment and accumulation of lipofuscin in RPE cells with subsequent cell death and patchy loss of RPE cells (in flat mounts), as well as thinning of the outer nuclear layer and later the inner nuclear layer in the succeeding days. ERG showed a progressive and significant decrease in a‑ and b‑ wave amplitudes in both case groups relative to baseline values and the controls (P NaIO3 injection into the retrobulbar venous plexus of pigmented rats can result in significant and progressive damage to the RPE and subsequently to the neuroretina of the injected eye, and may serve as a model of retinal degeneration.

To conduct an ocular health and safety assessment among mechanics in the Cape Coast Metropolis, Ghana.
This descriptive cross sectional study included 500 mechanics using multistage sampling. All participants filled a structured questionnaire on demographic data, occupational history and ocular health history. Study participants underwent determination of visual acuity (VA) using LogMAR chart, external eye examination with a handheld slit lamp biomicroscope, dilated fundus examination, applanation tonometry and refraction.
Out of 500 mechanics, 433 were examined (response rate, 87%) comprised of 408 (94.2%) male and 25 (5.8%) female subjects. The prevalence of visual impairment (i.e. presenting VA Eye injuries were prevalent among the mechanics as the use of eye protection was low. Eye safety should be made an integral part of the public health agenda in the Cape Coast Metropolis.

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.

Over the recent years, retina specialists have enoyed 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.

The status of the macula is a significant factor in determining final visual outcomes in rhegmatogenous retinal detachment (RRD) and should be considered in the timing of surgical repair. Several studies have shown that macula‑involving RRDs attain similar visual and anatomic outcomes when surgery is performed within seven days as compared to emergent surgery (within 24 hours). In contrast, surgery prior to macular detachment in macula‑sparing RRDs generally yields the best visual outcomes. In the case of macula‑sparing RRDs, it is not clear how long the macula may remain attached, therefore, standard practice dictates emergent surgery. Timing of presentation, examination findings, case complexity, co‑existing medical conditions, surgeon expertise, and timing and quality of access to operating facilities and staff, however, should all be considered in determining whether a macula‑sparing RRD requires immediate intervention or if equivalent visual and possibly better overall outcomes can be achieved with scheduled surgery within an appropriate time frame.

To describe a case of chronic graft versus host disease (GVHD) leading to severe dry eye and recurrent corneal perforation in both eyes, its stepwise management and histopathological reports.
Case Report: A 22-year-old woman with a history of thalassemia and subsequent high-dose chemotherapy followed by allogeneic bone marrow transplant (BMT) was referred to Farabi Eye Hospital. Despite aggressive medical and surgical intervention, corneal vascularization in her right eye progressed and led to corneal perforation. Cyanoacrylate glue was applied to seal the perforation, however it recurred. Multilayer amniotic membrane transplantation (AMT) was performed to seal the corneal perforation, which was effective for a short period. Subsequently, the corneal perforation recurred and penetrating keratoplasty was performed. After a few months deep vascularization and descemetocele occurred in the fellow left eye and the patient finally underwent therapeutic lamellar keratoplasty.
Patients with GVHD are at risk of severe dry eye and subsequent corneal vascularization. Recurrent and recalcitrant corneal perforation resistant to cyanoacrylate glue and multilayer AMT may occur. Proper systemic and ocular management alongside close collaboration with the hematologist is strongly recommended to control the condition.

To report a complication pertaining to subconjunctival bevacizumab injection as an adjunct to Ahmed Glaucoma Valve (AGV) implantation.
Case Report: A 54‑year‑old woman with history of complicated cataract surgery was referred for advanced intractable glaucoma. AGV implantation with adjunctive subconjunctival bevacizumab (1.25 mg) was performed with satisfactory results during the first postoperative week. However, 10 days after surgery, she developed wound dehiscence and tube exposure. The second case was a 33‑year‑old man with history of congenital glaucoma and uncontrolled IOP who developed AGV exposure and wound dehiscence after surgery. In both cases, for prevention of endophthalmitis and corneal damage by the unstable tube, the shunt was removed and the conjunctiva was re‑sutured.
The potential adverse effect of subconjunctival bevacizumab injection on wound healing should be considered in AGV surgery.

Diffuse unilateral subacute neuroretinitis (DUSN), a form of posterior uveitis, is secondary to the presence of a highly motile nematode in the intraretinal or subretinal space. Herein, we report a case of DUSN that was successfully managed by an intravitreal injection of triamcinolone and laser therapy.
Case Report: A middle‑aged man with complaint of decreased vision and marked unilateral vitritis and neuroretinitis. Fluorescein angiography revealed disc leakage, vessel wall staining, and diffuse track‑like transmission defects of the RPE. Optical coherence tomography confirmed the subretinal location of the worm. The patient received oral thiabendazole and an intravitreal injection of triamcinolone acetonide. After 10 days, media haziness decreased, and a live motile subretinal worm was identified. Direct laser photocoagulation was performed to destroy the worm. After two months, a localized chorioretinal scar developed and no further active inflammation and subretinal worms were detected.
Intravitreal steroids can be used safely in cases with DUSN and may help detect the causative worm for applying laser photocoagulation.