Fluid reservoir thickness and corneal oedema during closed eye scleral lens wear

Fisher, Damien; Collins, Michael J.; Vincent, Stephen J.

doi:10.1016/j.clae.2020.08.002

Cited by 14 publications

(23 citation statements)

References 54 publications

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“…Corneoscleral lenses display less movement upon blinking (up to ~ 0.5 mm) compared to rigid corneal lenses (1-2 mm), but more movement than scleral lens designs which settle back into the underlying conjunctival tissue over the course of the day [273]. Consequently, oxygen delivery is enhanced in corneoscleral designs compared to sealed scleral lenses, due to tear exchange and a thinner post-lens fluid reservoir which minimises corneal oedema [274,275]. Limbal compression must be avoided in corneoscleral designs since any insult at this anatomical location can potentially trigger a neovascular response [276].…”

Section: Corneoscleral and Scleral Lensesmentioning

confidence: 99%

“…Despite increased lens stability and comfort of scleral lenses compared to rigid corneal or corneoscleral lenses, a disadvantage of scleral lenses is the increased potential for corneal hypoxia in healthy eyes [179,274,275,[289][290][291][292], keratoconics [293], and following penetrating keratoplasty [294] due to reduced tear exchange [295][296][297] and the thicker central post-lens fluid reservoir (e.g. 200 µm compared to 20 µm in some corneoscleral designs).…”

Section: Corneoscleral and Scleral Lensesmentioning

confidence: 99%

See 1 more Smart Citation

Keratoconus: An updated review

Santodomingo-Rubido

Carracedo

Suzaki

et al. 2022

Contact Lens and Anterior Eye

Self Cite

333

204

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Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20-to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal crosslinking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.

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Section: Corneoscleral and Scleral Lensesmentioning

confidence: 99%

Section: Corneoscleral and Scleral Lensesmentioning

confidence: 99%

Keratoconus: An updated review

Santodomingo-Rubido

Carracedo

Suzaki

et al. 2022

Contact Lens and Anterior Eye

Self Cite

333

204

View full text Add to dashboard Cite

show abstract

“…However, short term wear studies in healthy subjects demonstrated corneal oedema following high Dk scleral lens wear ranging between 1.6-3.9% which is within the range of normal overnight physiological corneal swelling [106,489,[493][494][495]. A recent study showed that closed eye corneal swelling in normal eyes was higher with a high (716 ± 16 μm) compared with low (160 ± 7 μm) post-contact lens tear film thickness and suggested that modelling studies overestimated the impact of post-contact lens tear thickness on corneal swelling [496] Recently, a 12 month prospective study reported less than 2% increase in corneal thickness in both compromised corneas and healthy corneas following contemporary scleral lens wear [497].…”

Section: Physiological Complicationsmentioning

confidence: 93%

BCLA CLEAR - Contact lens complications

Stapleton

Bakkar

Carnt

et al. 2021

Contact Lens and Anterior Eye

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Contact lens-related complications are common, affecting around one third of wearers, although most are mild and easily managed. Contact lenses have well-defined anatomical and physiological effects on the ocular surface and can result in other consequences due to the presence of a biologically active material. A contact lens interacts with the tear film, ocular surface, skin, endogenous and environmental microorganisms, components of care solutions and other antigens which may result in disease specific to contact lens wear, such as metabolic or hypersensitivity disorders. Contact lens wear may also modify the epidemiology or pathophysiology of recognised conditions, such as papillary conjunctivitis or microbial keratitis. Wearers may also present with intercurrent disease, meaning concomitant or pre-existing conditions unrelated to contact lens wear, such as allergic eye disease or blepharitis, which may complicate the diagnosis and management of contact lens-related disease.Complications can be grouped into corneal infection (microbial keratitis), corneal inflammation (sterile keratitis), metabolic conditions (epithelial: microcysts, vacuoles, bullae, tight lens syndrome, epithelial oedema; stromal: superficial and deep neovascularisation, stromal oedema [striae/folds], endothelial: blebs, polymegethism/ pleomorphism), mechanical (corneal abrasion, corneal erosion, lens binding, warpage/refractive error changes; superior epithelial arcuate lesion, mucin balls, conjunctival epithelial flaps, ptosis, discomfort), toxic and allergic disorders (papillary conjunctivitis, solution-induced corneal staining, incomplete neutralisation of peroxide, Limbal Stem Cell Deficiency), tear resurfacing disorders/dry eye (contact lens-induced dry eye, Meibomian gland dysfunction, lid wiper epitheliopathy, lid parallel conjunctival folds, inferior closure stain, 3 and 9 o'clock stain, dellen, dimple veil) or contact lens discomfort. This report summarises the best available evidence for the classification, epidemiology, pathophysiology, management and prevention of contact lensrelated complications in addition to presenting strategies for optimising contact lens wear.

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“…Owing to small differences in the initial fluid reservoir thickness across the different lens thickness conditions, a series of corrections were applied to each individuals' total corneal edema data measured in this experiment because the fluid reservoir thickness is known to affect the magnitude of corneal edema. 32,33…”

Section: Methodsmentioning

confidence: 99%

Scleral Lens Thickness and Corneal Edema Under Closed Eye Conditions

Fisher

Collins

Vincent

2021

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

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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. Data were corrected for variations in initial fluid reservoir thickness and compared with predictions from theoretical modeling of overnight scleral lens wear.Results:Scleral lens–induced central corneal edema was primarily stromal in nature. The mean±standard error of corrected total corneal edema was 4.31%±0.32%, 4.55%±0.42%, 4.92%±0.50%, and 4.83%±0.22% for the 150-, 300-, 600-, and 1,200-μm lenses, respectively. No significant differences in the corrected total corneal edema were observed across all thickness groups (P=0.20). Theoretical modeling of overnight scleral lens wear seemed to overestimate the relative increase in central corneal edema as a function of decreasing lens Dk/t for values lower than 25.Conclusion:The magnitude of scleral lens–induced central corneal edema during short-term closed eye lens wear did not vary significantly with increasing central lens thickness. Theoretical modeling of overnight closed eye scleral lens wear seems to overestimate the effect of increasing lens thickness.

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Fluid reservoir thickness and corneal oedema during closed eye scleral lens wear

Cited by 14 publications

References 54 publications

Keratoconus: An updated review

Keratoconus: An updated review

BCLA CLEAR - Contact lens complications

Scleral Lens Thickness and Corneal Edema Under Closed Eye Conditions

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