Publications by authors named "Vincent Stephen"

Purpose: To explore the associations between myopia defocus dosage (MDD), aberration coefficients (primary spherical aberration and coma), and axial elongation in children undergoing orthokeratology (ortho-k) with back optic zone diameters (BOZD) of 5 mm and 6 mm over 2 years.

Methods: Data from 80 participants from two ortho-k studies were analyzed: 22 and 58 children wore lenses with 5-mm and 6-mm BOZD, respectively. Four MDD metrics were calculated from corneal topography data over a 5-mm pupil for the 1-month and 24-month visits: the circumferential, flat, steep, and volumetric MDD.

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Oxygen delivery and tear exchange are considered essential to maintain corneal homoeostasis during contact lens wear. Since the 1940s, fenestrations and back surface channels have been utilised in scleral, corneal rigid, and soft contact lenses in an attempt to enhance corneal oxygen transmission, facilitate the removal of carbon dioxide from the post-lens tear layer, minimise corneal oedema and prevent post-lens tear stagnation. This review examines the use of contact lens fenestrations and channels in both clinical and laboratory settings, and the effect of these modifications upon tear exchange and corneal oedema.

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Purpose: To quantify the magnitude and recovery of central and limbal corneal oedema induced by short-term unilateral eyelid closure without contact lens wear.

Methods: The left eye of 10 adults with healthy corneas was patched using a folded eye pad for 30 min. High-resolution optical coherence tomography images (which captured the limbal and central corneal regions simultaneously) were obtained before patching, immediately after eye opening and again at 1, 2, 5, 6, 9, 10, 14 and 15 mins after eyelid opening.

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Purpose: To quantify the impact of varying central fluid reservoir depth, lens thickness/mass and the addition of a peripheral fenestration upon scleral lens centration.

Methods: Ten young, healthy adults participated in a series of repeated-measures experiments involving short-term (90 min) open eye scleral lens wear. Scleral lens parameters (material, back optic zone radius, diameter, back vertex power and landing zone) were controlled across all experiments, and the central fluid reservoir depth (ranging from 144 to 726 μm), lens thickness (ranging from 150 to 1200 μm), lens mass (101-241 mg) and lens design (with or without a single 0.

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John Lennon has an enduring, instantly recognisable, iconic, spectacle look. However, prior to 1966, he was rarely seen wearing glasses in public. From ages 7 to 26, he effectively hid his myopia away, including a period of unsuccessful contact lens wear during Beatlemania.

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Purpose: To investigate the myopia control efficacy of novel Lenslet-ARray-Integrated (LARI) spectacle lenses with positive power lenslets (PLARI) and negative power lenslets (NLARI) worn for 1 year in myopic children.

Design: Randomized, double-masked, controlled clinical trial.

Participants: A total of 240 children 6 to 12 years of age with spherical equivalent refraction (SER) between -4.

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Article Synopsis
  • * Key factors for successful treatment involve evaluating the patient's visual needs, ocular health, and any previous surgeries, alongside strict contraindications for refractive surgery.
  • * Different approaches like laser ablation, corneal inlays, and conductive keratoplasty offer various ways to adjust corneal shape and focus, with recommended follow-up care to monitor the effects and complications after the procedure.
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Purpose: The fit and optical performance of a scleral lens is affected by the alignment of the landing zone with the underlying ocular surface. The aim of this research was to quantify the effect of landing zone toricity upon scleral lens fitting characteristics (rotation and decentration) and optics (lens flexure) during short-term wear.

Methods: Scleral lenses with nominal landing zone toricities of 0, 100, 150 and 200 μm were worn in a randomised order by 10 young healthy participants (mean [SD] 24 [7] years) for 30 min, with other lens parameters held constant.

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Professor George Smelser was a scientist who played a crucial role in advancing the understanding of the anatomical and physiological changes within the cornea during contact lens wear. In a series of unique experiments conducted in the early 1950s, using both humans and animal models, his research team provided the first conclusive evidence that contact lenses impaired the delivery of atmospheric oxygen to the cornea, resulting in an excess of lactate within the cornea and a subsequent ingress of water, leading to corneal oedema and disturbed vision (Sattler's veil). This historical note reviews the career of George Smelser, with particular emphasis on his contributions to understanding the importance of atmospheric oxygen in maintaining corneal homeostasis.

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Purpose: To report the characteristics (prevalence, severity, and location) of corneal epithelial microcysts and investigate associated risk factors in children wearing orthokeratology (ortho-k) lenses.

Method: Ninety-five myopic children wearing ortho-k lenses (examined by one of three independent investigators from March to September 2020) were included in this retrospective cross-sectional study. Pertinent data at baseline before ortho-k treatment and at the aftercare visits (the first visit when the microcysts were observed for children with microcysts, and the last visit before October 2020 for children without microcysts) were retrieved and analysed.

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Purpose: To quantify the magnitude of central and peripheral scleral lens-induced corneal oedema for a range of fluid reservoir thicknesses, and to compare these experimental results with theoretical models of corneal oedema both with and without limbal metabolic support (i.e., the lateral transport of metabolites and the influence of the limbal vasculature).

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Purpose: To compare changes in ocular aberrations in children wearing orthokeratology (ortho-k) lenses with a back optic zone diameter (BOZD) of 6 mm (6-MM group) or 5 mm (5-MM group) and their associations with axial elongation (AE) over two years.

Methods: Seventy Chinese children, aged 6 to < 11 years, with myopia between - 4.00 to - 0.

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Background: The retinal image quality derived from lower-order (LOA) and higher-order aberrations (HOA) for fixed 3-mm and photopic pupil diameters, in children undergoing combined 0.01% atropine and orthokeratology (AOK) versus those receiving orthokeratology alone (OK) over two years was evaluated.

Methods: The visual Strehl ratio based on the optical transfer function (VSOTF), derived from 2nd- to 4th-order terms (LOA and HOA combined), 2nd-order terms (LOA only), and 3rd- to 4th-order terms (HOA only) for fixed 3-mm and natural photopic pupil diameters, was compared between the two treatment groups.

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Purpose: One clinical approach to address poor front surface wettability during scleral lens wear is the use of a "reverse piggyback" system (a soft contact lens applied to the anterior surface of a scleral lens). The aim of this study was to compare the magnitude of corneal oedema induced following short-term reverse piggyback scleral lens wear and standard scleral lens wear.

Methods: Ten young (mean age 22 ± 6 years) healthy participants with normal corneas were recruited.

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Introduction: Despite the known associations between near work and myopia, and retinal image quality and eye growth, accommodation-induced changes in higher order aberrations (HOA's) and retinal image quality in children with different refractive errors are poorly understood.

Methods: Ocular HOA's were measured using a Hartmann-Shack wavefront sensor (COAS-HD, Wavefront Sciences) in 18 myopic and 18 age- and sex-matched non-myopic children during short-term accommodation tasks (four demands of 0, 3, 6 and 9 D) presented using a Badal optometer. Eighth order Zernike polynomials were fitted across a 2.

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This study examined anterior corneal, internal ocular, and total ocular higher order aberrations (HOA's), and retinal image quality in a non-myopic, paediatric cohort. Anterior corneal aberrations were derived from corneal topography data captured using a Placido disk videokeratoscope (E300, Medmont International), and whole eye HOA's were measured using a Hartmann-Shack wavefront sensor (COAS-HD, Wavefront Sciences). The associations between HOA's and age, sex, refractive error, and axial length were explored using correlation analyses.

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Anterior segment optical coherence tomography (AS-OCT) is a fundamental ophthalmic imaging technique. AS-OCT images can be examined by experts and segmented to provide quantitative metrics that inform clinical decision making. Manual segmentation of these images is time-consuming and subjective, encouraging software developers in the field to automate segmentation procedures.

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Background: Trans-scleral diode laser cycloablation (cyclodiode) is effective in the short-term management of refractory glaucoma where alternative treatments are not feasible. Long-term outcomes of 5-years or more are not well-documented, particularly in relation to intraocular pressure (IOP) control, need for further procedures and complications such as hypotony and phthisis.

Methods: A review was undertaken of patient medical records with refractory glaucoma who underwent cyclodiode at City Eye Centre in Brisbane from 2012 to 2016.

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Article Synopsis
  • * This paper conducts a comprehensive analysis of eight U-Net variants using four diverse OCT datasets, revealing minimal performance differences and emphasizing the importance of standardized comparisons.
  • * Results indicate that the standard U-Net model is effective for OCT segmentation, suggesting that more complex variants may not provide significant benefits and can complicate the process.
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Melioidosis is the clinical disease caused by the Gram-negative bacillus and is endemic to Northern Australia and Southeast Asia. It is commonly referred to as the 'great mimicker' because of its wide range of clinical presentations, often making diagnosis challenging. Isolated mediastinal lymphadenopathy as the presenting feature of melioidosis is rare and can be indistinguishable from tuberculosis or malignancy.

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Objectives: To examine the relationship between central lens thickness and central corneal edema during short-term closed eye scleral lens wear.

Methods: Nine participants (mean age 30 years) with normal corneas wore scleral lenses (Dk 141) under closed eye conditions on separate days with nominal center thicknesses of 150, 300, 600, and 1,200 μm. Epithelial, stromal, and total corneal edema were measured using high-resolution optical coherence tomography immediately after lens application and after 90 min of wear, before lens removal.

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Introduction: Studies examining the effect of fenestrating soft and corneal rigid contact lenses upon corneal oedema have yielded conflicting results. Although often utilised in clinical practice, no studies have quantified the effect of fenestrating a scleral contact lens upon corneal oedema. Therefore, the aim of this experiment was to examine the effect of incorporating a single peripheral fenestration on central corneal oedema during short-term open-eye scleral lens wear, while controlling for potential confounding variables.

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