Conjunctival prolapse during open eye scleral lens wear

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

doi:10.1016/j.clae.2020.09.001

Cited by 14 publications

(9 citation statements)

References 24 publications

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“…Both compression and suction forces [269] may contribute to conjunctival prolapse (an elevation of the perilimbal conjunctival tissue that may encroach the limbus), which has been observed in the region of the thickest fluid reservoir [270], although recent work suggests that the magnitude of lens settling at the limbus may be associated with conjunctival prolapse rather than excessive fluid reservoir thickness, asymmetry, or conjunctival compression ( [271]. Aside from cosmesis, the longer-term physiological effects of conjunctival prolapse are unknown.…”

Section: Compression and Suction Forces 951 Conjunctival Prolapsementioning

confidence: 99%

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BCLA CLEAR - Scleral lenses

Barnett

Courey

Fadel³

et al. 2021

Contact Lens and Anterior Eye

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Section: Compression and Suction Forces 951 Conjunctival Prolapsementioning

confidence: 99%

“…Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.clae.2021.02.001. Eye 44 (2021) [270][271][272][273][274][275][276][277][278][279][280][281][282][283][284][285][286][287][288]…”

Section: Appendix a Supplementary Datamentioning

confidence: 99%

BCLA CLEAR - Scleral lenses

Barnett

Courey

Fadel³

et al. 2021

Contact Lens and Anterior Eye

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“…1 provides accurate swelling predictions for ESCL wear. With ESL wear, the PoLTF thickness is smaller at the periphery than at the center and provides a PoLTF thickness profile representative of commercially available SLs [21,34].…”

Section: Lens Designmentioning

confidence: 97%

Central-to-peripheral corneal edema during wear of embedded-component contact lenses

Kim

Lin

Radke

2022

Contact Lens and Anterior Eye

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With active investigation underway for embedded-circuit contact lenses, safe oxygen supply of these novel lenses remains a question. Central-to-peripheral corneal edema for healthy eyes during wear of soft contact (SCL) and scleral lenses (SL) with embedding components is assessed. Methods: Various 2-dimensional (2D) designs of SL and SCL with embedded components are constructed on Comsol Multiphysics 5.5. Local corneal swelling associated with the designed lenses is determined by a recently developed 2D metabolic-swelling model. Settled central post-lens tear-film thicknesses (PoLTFs) are set at 400 μm and 3 μm for SL and SCL designs, respectively. Each lens design has an axisymmetric central and an axisymmetric peripheral embedment. Oxygen permeability (Dk) of the lens and the embedments ranges from 0 to 200 Barrer. Dimensions and location of the embedments are varied to assess optimal-design configurations to minimize central-to-peripheral corneal edema. Results: By adjusting oxygen Dk of the central embedment, the peripheral embedment, or the lens matrix polymer, corneal swelling is reduced by up to 2.5 %, 1.5 %, or 1.4 % of the baseline corneal thickness, respectively, while keeping all other parameters constant. A decrease in PoLTF thickness from 400 μm to 3 μm decreases corneal edema by up to 1.8 % of the baseline corneal thickness. Shifting the peripheral embedment farther out towards the periphery and towards the anterior lens surface reduces peak edema by up to 1.3 % and 0.6 % of the baseline corneal thickness, respectively.Conclusions: To minimize central-to-peripheral corneal edema, embedments should be placed anteriorly and far into the periphery to allow maximal limbal metabolic support and oxygen transport in the polar direction (i.e., the θ-direction in spherical coordinates). High-oxygen transmissibility for all components and thinner PoLTF thickness are recommended to minimize corneal edema. Depending on design specifications, less than 1 % swelling over the entire cornea is achievable even with oxygen-impermeable embedments.

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“…The action of compression and suction forces and the extent of limbal settling were associated with this phenomenon. 1 , 118 Back surface toricity or customized peripheral designs can reduce several aspects such as localized blanching, conjunctival prolapse, debris, formation of air bubbles, lens flexure and decentration. Impingement may be challenging to address with a slit-lamp in cases without associated compression; it occurs because of a steep lens edge.…”

Section: Measuring Scleral Lens Performancementioning

confidence: 99%

How Can We Best Measure the Performance of Scleral Lenses? Current Insights

Macedo-de-Araújo¹,

Fadel²,

Barnett³

2022

OPTO

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Scleral lenses (SLs) present several unique advantageous characteristics for patients. As these lenses are mainly fitted in severely diseased eyes, a thorough evaluation of the ocular surface before and after SL fitting and the on-eye SL fitting evaluation are essential and help minimize potential physiological complications. This review will explore the current and emerging techniques and instrumentation to best measure SL performance ensuring optimal lens fitting, visual quality, comfort and physiological responses, highlighting some potential complications and follow-up recommendations. A single physician could perform the great majority of evaluations. Still, the authors consider that the assessment of SL fitting should be a collaborative and multidisciplinary job, involving contact lens practitioners, ophthalmologists and the industry. This publication has reviewed the most up-to-date work and listed the most used techniques; however, the authors encourage the development of more evidence-based recommendations for SL clinical practice.

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Conjunctival prolapse during open eye scleral lens wear

Cited by 14 publications

References 24 publications

BCLA CLEAR - Scleral lenses

BCLA CLEAR - Scleral lenses

Central-to-peripheral corneal edema during wear of embedded-component contact lenses

How Can We Best Measure the Performance of Scleral Lenses? Current Insights

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