Journal of Ophthalmic and Vision Research
Volume:7 Issue: 1, Jan-Mar 2012

To compare the accuracy of noncycloplegic photorefraction (NCP) with that of cycloplegic refraction (CR) for detecting refractive amblyopia risk factors (RARFs) and to determine cutoff points. In this diagnostic test study, right eyes of 185 children (aged 1 to 14 years) first underwent NCP using the PlusoptiX SO4 photoscreener followed by CR. Based on CR results, hyperopia (+3.5 D or higher), myopia (-3 D or higher), astigmatism (1.5 D or higher), and anisometropia (1.5 D or higher) were set as diagnostic criteria based on AAPOS guidelines. The difference in the detection of RARFs by the two methods was the main outcome measure. RARFs were present in 57 (30.8%) and 52 (28.1%) of cases by CR and NCP, respectively, with an 89.7% agreement. In contrast to myopia and astigmatism, mean spherical power in hyperopic eyes was significantly different based on the two methods (P < 0.001), being higher with CR (+5.96 ± 2.13 D) as compared to NCP (+2.37 ± 1.36 D). Considering CR as the gold standard, specificities for NCP exceeded 93% and sensitivities were also acceptable (at least 83%) for myopia and astigmatism. Nevertheless, sensitivity of NCP for detecting hyperopia was only 45.4%. Using a cutoff point of +1.87 D, instead of +3.5 D, for hyperopia, sensitivity of NCP was increased to 81.8% with specificity of 84%. NCP is a relatively accurate method for detecting RARFs in myopia and astigmatism. Using an alternative cutoff point in this study, NCP may be considered an acceptable device for detecting hyperopia as well.

To evaluate the long-term outcomes of two-step versus single application of mitomycin-C (MMC) during photorefractive keratectomy (PRK) for high myopia. This randomized clinical trial included consecutive patients with high myopia (exceeding 7D). Patients underwent PRK and were randomized to two methods of MMC 0.02% application as follows: in the single application group, MMC was applied for 45 seconds followed by irrigation; in the two-step group MMC was used identically followed by repeat application for another 15 seconds and corneal surface irrigation. Visual acuity, refractive error, pachymetry, topography, corneal haze and complications were compared between the two groups 18 months after surgery. One hundred and forty patients (70 subjects in either study arm) underwent PRK according to the study protocol. Mean spherical equivalent refractive error was significantly reduced from baseline to -1.16±0.39 D in the single application group and to -1.07±0.39 D in the two-step group. Sixteen (11.5%) versus 8 (5.7%) eyes lost one or more line(s) of best corrected visual acuity in the single application group as compared to the two-step group (P=0.05). Corneal haze was observed in 18 (12.9%) and 8 (5.7%) eyes in the single application versus two-step group, respectively (P=0.04). Grade 3 corneal haze was not observed in the two-step group but occurred in five eyes (3.6%) in the single application group (P=0.03). No eyes developed corneal ectasia during the follow-up period. Two-step intraoperative application of MMC 0.02% in highly myopic eyes undergoing PRK can reduce the frequency and severity of haze formation.

To evaluate the long-term outcomes of two-step versus single application of mitomycin-C (MMC) during photorefractive keratectomy (PRK) for high myopia. This randomized clinical trial included consecutive patients with high myopia (exceeding 7D). Patients underwent PRK and were randomized to two methods of MMC 0.02% application as follows: in the single application group, MMC was applied for 45 seconds followed by irrigation; in the two-step group MMC was used identically followed by repeat application for another 15 seconds and corneal surface irrigation. Visual acuity, refractive error, pachymetry, topography, corneal haze and complications were compared between the two groups 18 months after surgery. One hundred and forty patients (70 subjects in either study arm) underwent PRK according to the study protocol. Mean spherical equivalent refractive error was significantly reduced from baseline to -1.16±0.39 D in the single application group and to -1.07±0.39 D in the two-step group. Sixteen (11.5%) versus 8 (5.7%) eyes lost one or more line(s) of best corrected visual acuity in the single application group as compared to the two-step group (P=0.05). Corneal haze was observed in 18 (12.9%) and 8 (5.7%) eyes in the single application versus two-step group, respectively (P=0.04). Grade 3 corneal haze was not observed in the two-step group but occurred in five eyes (3.6%) in the single application group (P=0.03). No eyes developed corneal ectasia during the follow-up period. Two-step intraoperative application of MMC 0.02% in highly myopic eyes undergoing PRK can reduce the frequency and severity of haze formation.

To assess the prevalence of allergic conjunctivitis in Gambia and to determine its epidemiologic features, seasonal variations and associated ocular and systemic conditions. Records of patients clinically diagnosed with allergic conjunctivitis between April 2007 and March 2008 were reviewed. Variables including age, sex, date of presentation, and systemic and ocular findings were recorded. A total of 7,912 patients were visited within the study period, out of which 624 (7.9%) were diagnosed with allergic conjunctivitis. The disease was equally distributed in male and female subjects, with high preponderance in children (54.5%). Most patients (60.7%) presented during the dry season as compared to the rainy season. Refractive error was the most common ocular condition associated with the condition present in 7.4% of patients while the most common systemic association was asthma, reported in 1.4% of cases. Allergic conjunctivitis in Gambia is more common in children than in adults and has seasonal variation with more patients presenting during dry seasons. Refractive errors are the most common ocular problem associated with the disease and asthma is a systemic association.

To evaluate the effect of tetracaine on intraocular pressure (IOP) in normal and hypertensive rabbit eyes. The study was conducted on 12 healthy rabbits as controls and 6 healthy rabbits in which an experimental model of ocular hypertension (OHT) was induced by administration of 70 mL/kg of tap water through an orogastric tube. One drop of tetracaine was instilled in the left eye while a drop of normal saline (placebo) was applied to the right eye of the control group. IOP was measured before and 0, 5, 10,15, 20, 25, 30, 35 and 40 minutes after drop administration in this group. The OHT group also received one drop of tetracaine and normal saline in the left eyes and right eyes respectively, immediately after water loading; the instillation of drops was repeated after 55 minutes. IOP was measured before and 0, 5, 10, 15, 20, 25, 30, 35,40, 55, 70, 85, 100 and 115 minutes after water loading in this group. Tetracaine treated eyes in both groups (ocular hypertensive and normal controls) demonstrated significant IOP reduction at time zero (immediately after drop instillation) which was sustained up to 20 minutes, as compared to placebo treated eyes (P)

To compare electroretinogram (ERG) characteristics in patients with retinitis pigmentosa (RP) and normal subjects using frequency domain analysis. Five basic ERG recordings were performed in normal subjects and patients with a clinical diagnosis of RP according to the ISCEV (International Society of Clinical Electrophysiology of Vision) protocol. Frequency domain analysis was performed by MATLAB software. Different frequency domain parameters were compared between the study groups. Peak frequency (Fmod) of flicker and oscillatory responses in RP patients showed significant.

Tumor necrosis factor (TNF) alpha is a pro-inflammatory cytokine produced by macrophages and T-cells. It plays an important role both in inflammation and apoptosis. In the eye, TNF alpha appears to have a role in the pathogenesis of inflammatory, edematous, neovascular and neurodegenerative disorders. Several TNF-blocking drugs have been developed and approved, and are in clinical use for inflammatory diseases such as rheumatoid arthritis, psoriasis and ankylosing spondylitis. TNF alpha blockers are widely used in ophthalmology as an off-label alternative to «traditional» immunosuppressive and immune-modulatory treatments in noninfectious uveitis. Preliminary studies suggest a positive effect of intravenously administered TNF alpha blockers, mainly infliximab, for treating refractory diabetic macular edema and neovascular age-related macular degeneration. Unfortunately, much of the current data raises considerable safety concerns for intravitreal use of TNF alpha inhibitors, in particular, intraocular inflammatory responses have been reported after intravitreal injection of infliximab. Results of dose-finding studies and humanized antibody or antibody fragments (e. g. adalimumab) are anticipated in the coming years; these will shed light on potential benefits and risks of local and systemic TNF alpha blockers used for treatment of diseases of the retina and choroid.

Accumulation of misfolded proteins in the endoplasmic reticulum (ER) and their aggregation impair normal cellular function and can be toxic, leading to cell death. Prolonged expression of misfolded proteins triggers ER stress, which initiates a cascade of reactions called the unfolded protein response (UPR). Protein misfolding is the basis for a variety of disorders known as ER storage or conformational diseases. There are an increasing number of eye disorders associated with misfolded proteins and pathologic ER responses, including retinitis pigmentosa (RP). Herein we review the basic cellular and molecular biology of UPR with focus on pathways that could be potential targets for treating retinal degenerative diseases.

To report an interesting case of concomitant bilateral Terrien''s marginal degeneration-like corneal ectasia and posterior polymorphous corneal dystrophy in a young man with quiescent rheumatoid arthritis. Case Report: A 24-year-old man with history of rheumatoid arthritis presented with bilateral decreased vision since four years ago. Slit lamp examination revealed bilateral circumferential peripheral corneal thinning and bulging with vascularization and lipid deposition in addition to band-like lesions in descemet''s membrane. Previous records revealed no gross corneal abnormalities up to 4 years ago. Corneal lesions were compatible with bilateral circumferential Terrien''s marginal degeneration concomitant with posterior polymorphous dystrophy. To our knowledge, this is the first report of concomitant bilateral Terrien''s marginal degeneration with peripheral corneal ectasia and posterior polymorphous dystrophy in a patient with rheumatoid arthritis. Bilateral circumferential involvement, younger age at presentation and total peripheral corneal ectasia as observed in this case are not typical for classic Terrien''s marginal degeneration.

To report a case of early decomposition of retained heavy silicone oil droplets. Case Report: The single highly myopic eye of a 16-year-old boy with history of scleral buckling and buckle revision developed redetachment due to inferior retinal dialysis. The patient underwent pars plana vitrectomy and injection of heavy silicone oil. Early emulsification of the silicone oil was observed following surgery, which was removed 4 weeks later in another operation. Retained heavy silicone droplets lost their heavier- than-water specific gravity within 2 months together with extensive iris depigmentation, and release of pigment granules into the anterior chamber and vitreous cavity. This case report demonstrates that heavy silicone oil droplets can undergo in vivo chemical decomposition with possible toxic effects on ocular tissues.

To present a patient with overlapping choriocapillaritis syndromes who first presented as a typical case of multiple evanescent white dot syndrome (MEWDS) and later with characteristic findings compatible with multifocal choroiditis (MFC). Case Report: A 40-year-old myopic woman presented with a paracentral scotoma OS. Fundus examination revealed pale discolored areas around the optic disc corresponding to faintly hyperfluorescent areas on fluorescein angiography (FA). On indocyanine green angiography (ICGA) there was extensive peripapillary hypofluorescence and confluent hypofluorescent dots superiorly. According to the clinical picture, a diagnosis of MEWDS was made. In 4 weeks, the visual field reverted to normal together with almost complete regression of hypofluorescence on ICGA. However, 4 months later fundus examination revealed some scars, a finding not typical for MEWDS. Besides, she developed another scotoma 12 months later accompanied by photopsia and the fundus illustrated more numerous scars than one year earlier. ICGA showed hypofluorescent areas corresponding to the scotoma delineated by visual field testing. The pattern of this recurrence clearly corresponded to MFC. This case illustrates an overlap between two entities, MEWDS and MFC in two sequential episodes. FA and fundus autofluorescence accounted for the lesions and optical coherence tomography showed damage to the photoreceptor outer segments, but only ICGA correlated well with functional evolution.

Herein we introduce a simple approach for clearing an edematous cornea during vitreoretinal surgery in eyes with decompensated corneal endothelium, allowing the surgeon to postpone penetrating keratoplasty. This technique was performed in 3 eyes by filling the anterior chambers with air or silicone oil, and sufficiently cleared the media for completion of vitrectomy. This simple technique enables completion of the vitrectomy without a temporary keratoprosthesis and penetrating keratoplastyin eyes with corneal edema due to endothelial decompensation.