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BMJ Open Ophthalmology 2022The purpose of this paper is to review the basic principles of linear optics. A paraxial optical system is represented by a symplectic matrix called the transference,... (Review)
Review
The purpose of this paper is to review the basic principles of linear optics. A paraxial optical system is represented by a symplectic matrix called the transference, with entries that represent the fundamental properties of a paraxial optical system. Such an optical system may have elements that are astigmatic and decentred or tilted. Nearly all the familiar optical properties of an optical system can be derived from the transference. The transference is readily obtainable, as shown, for Gaussian and astigmatic optical systems, including systems with elements that are decentred or tilted. Four special systems are described and used to obtain the commonly used optical properties including power, refractive compensation, vertex powers, neutralising powers, the generalised Prentice equation and change in vergence across an optical system. The use of linear optics in quantitative analysis and the consequences of symplecticity are discussed. A systematic review produced 84 relevant papers for inclusion in this review on optical properties of linear systems. Topics reviewed include various magnifications (transverse, angular, spectacle, instrument, aniseikonia, retinal blur), cardinal points and axes of the eye, chromatic aberrations, positioning and design of intraocular lenses, flipped, reversed and catadioptric systems and gradient indices. The optical properties are discussed briefly, with emphasis placed on results and their implications. Many of these optical properties have applications for vision science and eye surgery and some examples of using linear optics for quantitative analyses are mentioned.
Topics: Astigmatism; Eyeglasses; Humans; Lenses, Intraocular; Optics and Photonics; Refraction, Ocular
PubMed: 35452208
DOI: 10.1136/bmjophth-2021-000932 -
Ophthalmic Research 2023The iStent (Glaukos Corporation; Laguna Hills, CA, USA) is one of the minimally invasive glaucoma devices. It can be inserted at the time of phacoemulsification or as a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The iStent (Glaukos Corporation; Laguna Hills, CA, USA) is one of the minimally invasive glaucoma devices. It can be inserted at the time of phacoemulsification or as a stand-alone procedure to lower the intraocular pressure (IOP).
OBJECTIVE
Our aim was to conduct a systematic review and meta-analysis comparing the effect of iStent insertion at the time of phacoemulsification with phacoemulsification alone in patients with ocular hypertension or open-angle glaucoma.
METHODS
We searched EMBASE, MEDLINE (OVID and PubMed), CINAHL, and Cochrane Library for articles published between 2008 and June 2022 (PRISMA 2020 for the checklist). Studies comparing the IOP-lowering effect of iStent with phacoemulsification versus phacoemulsification alone were included. The endpoints were IOP reduction (IOPR) and the mean reduction in the number of glaucoma drops. A quality-effects model was used to compare both surgical groups.
RESULTS
Ten studies were included, reporting on 1,453 eyes. Eight hundred fifty three eyes had the combined iStent and phacoemulsification, and 600 eyes underwent phacoemulsification alone. IOPR was higher in the combined surgery at of 4.7 ± 2 mm Hg compared to 2.8 ± 1.9 mm Hg in phacoemulsification alone. A greater decrease in postoperative eye drops was noted in the combined group having a decrease of 1.2 ± 0.3 eye drops versus of 0.6 ± 0.6 drops in isolated phacoemulsification. The quality effect model showed an IOPR weighted mean difference (WMD) of 1.22 mm Hg (confidence interval [CI]: [-0.43, 2.87]; Q = 315.64; p < 0.01; I2 = 97%) and decreased eye drops WMD 0.42 drops (CI: [0.22, 0.62]; Q = 42.6; p < 0.01; I2 = 84%) between both surgical groups. Subgroup analysis shows that the new generation iStent may be more effective in reducing IOP.
CONCLUSION
iStent has a synergetic effect with phacoemulsification. The reduction of IOP and glaucoma eye drops was higher when iStent is combined with phacoemulsification compared with isolated phacoemulsification.
Topics: Humans; Phacoemulsification; Glaucoma, Open-Angle; Glaucoma Drainage Implants; Glaucoma; Intraocular Pressure; Trabecular Meshwork; Ophthalmic Solutions
PubMed: 37245507
DOI: 10.1159/000531077 -
The Ocular Surface Jul 2023Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality,...
Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO) and soil pollution (from chromium), but not from air pollution from CO or PM. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.
Topics: Humans; Air Pollution; Particulate Matter; Dry Eye Syndromes; Conjunctiva; Life Style
PubMed: 37062427
DOI: 10.1016/j.jtos.2023.04.007 -
Indian Journal of Ophthalmology May 2021The incidence of leishmaniasis is reported to be up to 1 million per year. To date, there has been no comprehensive review describing the diversity of clinical... (Review)
Review
The incidence of leishmaniasis is reported to be up to 1 million per year. To date, there has been no comprehensive review describing the diversity of clinical presentations of ocular leishmaniasis (OL) and its treatment. This systematic review aims to address this knowledge gap and provide a summary of the clinical presentation, natural course, and treatment options for OL. Our study identified a total of 57 published articles as describing cases of OL involving: adnexa (n = 26), orbit (n = 1), retina (n = 7), uvea (n = 18) and cornea (n = 6). Though well described and easily treated, palpebral leishmaniasis is often misdiagnosed and may lead to chronic issues if untreated. The retinal manifestations of Leishmaniasis consist of self-resolving hemorrhages secondary to thrombocytopenia. Two main uveitis etiologies have been identified: uveitis in the context of active Leishmanial infection (associated with immunosuppression) and uveitis occurring as an immune reconstitution syndrome. Corneal involvement in most geographic areas generally follows an aggressive course, most often ending in corneal perforation if left untreated. In the Americas, a chronic indolent interstitial keratitis may also occur. Topical steroids are of little use in keratitis (systemic antileishmanials being the cornerstone of treatment). However, these are essential in cases of uveitis, with or without concomitant systemic antileishmanial therapy. In conclusion, though ocular involvement in Leishmaniasis is rare, severe sight-threatening consequences follow if left untreated. Early diagnosis, enthusiastic follow-up and aggressive treatment are essential for good outcomes.
Topics: Cornea; Corneal Perforation; Humans; Keratitis; Leishmaniasis; Uveitis
PubMed: 33913831
DOI: 10.4103/ijo.IJO_2232_20 -
Survey of Ophthalmology 2023Choroidal osteoma is a benign ossifying tumor within the choroid. Complications associated with choroidal osteoma, including disruption of retinal pigment epithelium,... (Review)
Review
Choroidal osteoma is a benign ossifying tumor within the choroid. Complications associated with choroidal osteoma, including disruption of retinal pigment epithelium, atrophy of photoreceptors, subretinal fluid, and choroidal neovascularization, present challenges for clinicians, and management remain controversial. We performed a comprehensive search in the PubMed, EMBASE, and Ovid databases for published studies and case reports relating to the management of choroidal osteoma. Since it was first described in 1978, various case reports of ocular complications associated with choroidal osteoma have been documented, and various therapies have yielded different outcomes. We systematically evaluate the literature published on this rare entity.
Topics: Humans; Choroid Neoplasms; Choroid; Osteoma; Choroidal Neovascularization; Retinal Pigment Epithelium; Fluorescein Angiography; Tomography, Optical Coherence
PubMed: 37321477
DOI: 10.1016/j.survophthal.2023.06.002 -
Journal of Cataract and Refractive... Sep 2023In this meta-analysis and systematic literature review of refractive outcomes after Descemet membrane endothelial keratoplasty (DMEK), the extent of the refractive shift... (Meta-Analysis)
Meta-Analysis
In this meta-analysis and systematic literature review of refractive outcomes after Descemet membrane endothelial keratoplasty (DMEK), the extent of the refractive shift and an overview of reasons for refractive shift after DMEK are provided. The PubMed library was screened for articles containing the terms "Descemet membrane endothelial keratoplasty," "DMEK," "Descemet membrane endothelial keratoplasty combined with cataract surgery," "triple-DMEK" combined with "refractive outcomes," "refractive shift," and "hyperopic shift." The refractive outcomes after DMEK were analyzed and compared using a fixed and random effects model. The overall mean change of the spherical equivalent outcome when compared with the preoperative value in cases of DMEK or when compared with the preoperative target refraction in cases of DMEK combined with cataract surgery was +0.43 diopters (D) (95% CI, 0.31-0.55). When DMEK is combined with cataract surgery, a target refraction of -0.5 D is recommended to achieve emmetropia. Changes in the posterior corneal curvature are identified as the main cause of the refractive hyperopic shift.
Topics: Humans; Visual Acuity; Descemet Stripping Endothelial Keratoplasty; Refraction, Ocular; Hyperopia; Cataract; Retrospective Studies; Fuchs' Endothelial Dystrophy; Descemet Membrane; Endothelium, Corneal
PubMed: 37144644
DOI: 10.1097/j.jcrs.0000000000001212 -
Journal of Cataract and Refractive... May 2021Twenty-eight case reports and case series published between 2000 and 2019 concerning laser refractive surgery in patients with corneal dystrophies, resulting in 173 eyes...
Twenty-eight case reports and case series published between 2000 and 2019 concerning laser refractive surgery in patients with corneal dystrophies, resulting in 173 eyes from 94 patients, were included in this systematic review. Best results were achieved in posterior corneal polymorphous and Cogan dystrophy. Unfavorable results were found in Avellino dystrophy and Fuchs endothelial corneal dystrophy (FECD). Photorefractive keratectomy was not indicated in Meesmann and Avellino dystrophy. Laser in situ keratomileusis was indicated in posterior polymorphous corneal dystrophy but not in FECD, Avellino, or Cogan dystrophy. Small-incision lenticule extraction and other dystrophies such as lattice, fleck, Lisch, or François did not achieve enough scientific evidence to report any recommendation.
Topics: Cornea; Corneal Dystrophies, Hereditary; Humans; Keratomileusis, Laser In Situ; Lasers, Excimer; Photorefractive Keratectomy
PubMed: 33149045
DOI: 10.1097/j.jcrs.0000000000000468 -
Ophthalmology. Retina Jun 2023To characterize the presentation, management, and outcomes of suprachoroidal hemorrhage (SCH). (Meta-Analysis)
Meta-Analysis Review
TOPIC
To characterize the presentation, management, and outcomes of suprachoroidal hemorrhage (SCH).
CLINICAL RELEVANCE
Suprachoroidal hemorrhage is a potentially devastating condition but there is no high-quality evidence for the prognosis or management of SCH.
METHODS
We performed a systematic review and meta-analysis of peer-reviewed studies of SCH published in PubMed, EMBASE, Web of Science, or Google Scholar between January 1, 1990, and September 1, 2022. The protocol was prospectively registered on the Open Science Framework (https://osf.io/69v3q/). Random-effects models were used to calculate the pooled estimate and 95% confidence intervals (CIs) for visual acuity (VA) and anatomic outcomes. Univariable and multivariable random-effects meta-regressions were performed to determine factors associated with VA outcomes and anatomic success, defined as the retina attached at the last follow-up.
RESULTS
Sixty-eight studies comprising 1246 eyes of 1245 patients were included, with mean (standard deviation [SD]) follow-up of 14.0 (9.4) months. The pooled estimate (95% CI) for mean change in logarithm of the minimum angle of resolution (logMAR) VA from baseline to the last follow-up was -0.98 (-1.22 to -0.74) (I = 88.4%), with 72.0% (63.5%-80.5%) (I = 74.3%) achieving VA improvement of ≥ 0.3 logMAR (3-line improvement in ETDRS VA), 39.6% (32.5%-46.7%) (I = 83.2%) achieving final VA of 1.0 logMAR (Snellen equivalent 20/200) or better, and 75.5% (68.4%-82.7%) (I = 74.7%) achieving anatomic success. Studies with predominantly nonspontaneous SCH and greater percent of eyes receiving systemic steroids were associated with greater improvement in logMAR VA, a greater proportion of eyes with VA improvement ≥ 0.3 logMAR, and greater proportion of eyes achieving anatomic success (all P < 0.05 univariable meta-regression). Studies with greater percent of eyes treated surgically were associated with greater proportion of eyes with VA improvement of ≥ 0.3 logMAR in (P < 0.05, univariable and multivariable analysis). The mean (SD) quality score across studies was 13.9 (2.3) out of 24, and outcomes were of very low certainty of evidence.
CONCLUSION
Although limited by heterogeneous observational studies, published reports of SCH indicate that most eyes with SCH experience some degree of VA improvement and anatomic success. However, final VA outcomes remain poor, with most cases resulting in severe visual impairment or blindness.
FINANCIAL DISCLOSURE(S)
Proprietary or commercial disclosure may be found after the references.
Topics: Humans; Retina; Prognosis; Hemorrhage
PubMed: 36858317
DOI: 10.1016/j.oret.2023.02.011 -
Journal of Affective Disorders Jun 2023Individuals with a severe mental illness (SMI), such as bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia (SZ), have increased rates of... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Individuals with a severe mental illness (SMI), such as bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia (SZ), have increased rates of cardiovascular and cerebrovascular disease. Interestingly, it has been reported that retinal microvessels, a proxy cerebrovascular measure, non-invasively assessed via retinal imaging, predict future cardiovascular disease, with some studies also showing anomalous retinal microvascular caliber in SMI. Therefore, this review and meta-analysis evaluated whether retinal microvascular caliber differs between individuals with SMI vs controls and summarized current findings.
METHODS
A systematic literature search for retinal microvascular caliber and SMI was conducted in Embase and MEDLINE. Studies needed to be published in English before 2022 December 1st and examine retinal microvascular caliber in individuals diagnosed with a SMI. Finally, a meta-analysis of arteriolar and venular caliber in SMI case-controlled studies was also conducted.
RESULTS
The search yielded 65 unique articles, 11 were included in the review and 6 in the meta-analysis. The meta-analysis found that the SMI group had significantly wider venules than controls (SMD = 0.53; 95 % CI = 0.24, 0.81; p = 0.0004) but not arterioles (SMD = 0.07; 95 % CI = -0.29, 0.44; p = 0.70). Additionally, the systematic review found that poorer retinal microvascular health is associated with greater illness severity.
LIMITATIONS
Large heterogeneity of findings and small sample size.
CONCLUSION
This systematic review and meta-analysis found that SMI, specifically SZ, is associated with wider retinal venules. Retinal imaging, a fast, cost-effective, and non-invasive assay of cerebrovascular health, may provide insight into the pathophysiological processes of SMI. However, future longitudinal studies investigating these findings are warranted.
Topics: Humans; Bipolar Disorder; Depressive Disorder, Major; Schizophrenia; Retina; Cerebrovascular Disorders
PubMed: 36958491
DOI: 10.1016/j.jad.2023.03.040 -
International Ophthalmology Feb 2024Pediatric keratoconus (pediatric KC) causes progressive deformation of the cornea in children and adolescents, leading to a gradual loss of vision and a need for... (Review)
Review
BACKGROUND
Pediatric keratoconus (pediatric KC) causes progressive deformation of the cornea in children and adolescents, leading to a gradual loss of vision and a need for rehabilitation. However, new treatments may halt the disease and prevent worse outcomes that require penetrating keratoplasty and its associated morbidity and high cost, irreversible loss of vision, and amblyopia. Few systematic reviews focus on keratoconus-and even fewer, on pediatric KC.
METHODS
Here, we report a systematic scoping review of pediatric KC epidemiology and discuss the studies reporting data on pediatric KC. We used PRISMA-ScR methodology and checklists in the elaboration of the manuscript. The inclusion criteria were: English language; publication between August 7, 1998, and August 7, 2019 (20 years); theme of the study pediatric KC epidemiology. The search strategy: searches of the PubMed-MEDLINE database and Cochrane Database of Systematic Reviews, using eight combinations of the following MeSH terms: keratoconus; child; incidence; prevalence; pediatrics; adolescent; epidemiology.
RESULTS
We charted and reviewed the selected articles. Initial searches included 1802 records; after the exclusion of article duplicates, we screened 777 records, read 97 articles in full text, and included 76 articles in this review.
CONCLUSIONS
Recent epidemiological studies with better methodologies demonstrated increased prevalence rates in comparison to the older literature. This effect may be due to better diagnostic methods and better sample selection than those in historical studies. Diagnosis remains a major challenge as the early disease is usually asymptomatic. Economic and social aspects of pediatric KC remain understudied in the pediatric literature. Global, inclusive, and proactive screening studies in schools are imperative to better understand the great impact of this disease in the young.
Topics: Adolescent; Humans; Child; Keratoconus; Cornea; Keratoplasty, Penetrating; Morbidity; Incidence
PubMed: 38347389
DOI: 10.1007/s10792-024-03010-2