Microcystic corneal oedema associated with over-wear of decentred orthokeratology lenses during COVID-19 lockdown

Guo, Biyue; Cho, Pauline; Efron, Nathan

doi:10.1080/08164622.2021.1896944

Cited by 6 publications

(7 citation statements)

References 10 publications

(12 reference statements)

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“…No cases of microbial keratitis were observed during the 2‐year study. One participant with diffuse Grade 4 microcysts and corneal haze was observed during the COVID‐19 pandemic lockdown, with details reported previously 14 . The incidence of non‐inflammatory infiltrates observed here was higher than previous findings 7 .…”

Section: Discussionsupporting

confidence: 75%

“…In the current study, 21 subjects presented with microcysts at different visits (Grade 1–Grade 4). Except for one severe case with corneal haze 14 and one who stopped lens wear in the early stage of the study, subjects presenting with more than Grade 2 microcysts ( n = 10) resumed lens wear after the condition had subsided to a low to moderate level (≤Grade 2) after temporary lens discontinuation (26–73 days).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: A 2‐year randomised clinical trial

Guo,

Cheung,

Kojima

et al. 2023

Ophthalmic Physiologic Optic

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PurposeTo compare axial elongation (AE) and treatment zone (TZ) characteristics in children wearing 6 mm or 5 mm back optic zone diameter (BOZD) orthokeratology (ortho‐k) lenses over 2 years.MethodsForty‐five (6 to <11 years of age) myopic (−4.00 to −0.75 D) children of Chinese ethnicity were randomly assigned to use the two different lens designs (23 and 22 wore the 6 and 5 mm lenses, respectively). Data collection was performed at baseline and every 6‐months after commencing lens wear.ResultsAfter 24 months, subjects wearing lenses with a 5 mm BOZD achieved smaller TZ diameter (horizontal: 2.69 ± 0.28 vs. 3.84 ± 0.39 mm; vertical: 2.65 ± 0.22 vs. 3.42 ± 0.34 mm, p < 0.001) and less AE (0.15 ± 0.21 vs. 0.35 ± 0.23, p = 0.005) compared to those using the 6 mm design, with no difference in choroidal thickness (ChT) changes (p = 0.93). A significant increase in ChT, using pooled data analysis, was noted at the 6‐month (11.8 ± 19.77 μm, p < 0.001) and 12‐month (12.0 ± 23.7 μm, p = 0.004) visits, compared to baseline, indicating a transient change in ChT. Significant associations were noted, using linear mixed models, between AE and the TZ diameters (p < 0.003) after adjusting for baseline data. A very weak association was found between ChT changes and AE, with the effect size close to zero.ConclusionsSmaller BOZD ortho‐k lenses resulted in a smaller TZ diameter, which was associated with less AE after 2 years of treatment. The changes in ChT played a very weak role, suggesting that other factors may contribute more to the reduced AE in subjects wearing lenses having a smaller BOZD.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: A 2‐year randomised clinical trial

Guo,

Cheung,

Kojima

et al. 2023

Ophthalmic Physiologic Optic

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“…The lens parameters were determined using computer‐aided software. A lens was considered as an unsuccessful fit when poor corneal response and/or clinically significant lens decentration was observed: significant decentration (>1.0 mm) or moderate decentration (>0.5 mm) with associated symptoms, such as compromised vision and/or affected ocular integrity 31 . Lenses were replaced on an annual basis and/or when any of the following modifications was indicated: (a) residual myopia exceeded 0.50 D on two consecutive visits, (b) unaided visual acuity was worse than 0.18 LogMAR in either eye, (c) clinically significant lens decentration.…”

Section: Methodsmentioning

confidence: 99%

One‐year results of the Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: a prospective randomised clinical trial

Guo

Cheung

Kojima

et al. 2021

Ophthalmic Physiologic Optic

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Purpose: To present the 1-year results of the Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study, which aims to investigate the myopia control effect of orthokeratology (ortho-k) lenses with different back optic zone diameters (BOZD). Method: Children, aged 6 to <11 years, having myopia −4.00 D to −0.75 D, were randomly assigned to wear ortho-k lenses with 6 mm (6-MM group) or 5 mm (5-MM group) BOZD. Data collection included changes in refraction, vision, lens performance and binding, ocular health conditions, axial length and characteristics of the treatment zone (TZ) area. Results: The 1-year results of 34 and 36 subjects (right eye only) in the 6-MM and 5-MM groups, respectively, are presented. No significant differences in baseline demographics were found between the groups (p > 0.05). The first-fit success rates, based on satisfactory centration at the 1-month visit, were 100% and 94% respectively. Horizontal TZ size was 0.92 mm and 0.72 mm smaller in the 5-MM group at the 6-month and 12-month visits, respectively (p < 0.05). At the 12month visit, no significant between-group differences were found in the incidence of corneal staining (low grade only), lens binding and visual performance (all p > 0.05). Axial elongation was slower in the 5-MM group (0.04 AE 0.15 mm) than the 6-MM group (0.17 AE 0.13 mm) (p = 0.001). A significant positive correlation was observed between the horizontal TZ size and axial elongation (r = 0.36, p = 0.006). Conclusion: Clinical performance of the two ortho-k lenses was similar, indicating that a smaller BOZD (5 mm) did not affect lens performance or ocular integrity. However, a smaller BOZD led to a reduced TZ, with retardation of axial elongation by 0.13 mm compared to conventional 6 mm BOZD ortho-k lenses after one year of lens wear.

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“…Due to the use of high Dk rigid lens materials, microcysts have been observed only occasionally in ortho-k lens wearers and have not warranted clinical management due to the small numbers detected [69,109]. Anecdotal reports indicate that microcysts are more commonly seen in children who require higher myopia correction and in those who wear ortho-k lenses for longer periods overnight [150], which may be due to reduced oxygen availability to the cornea.…”

Section: Microcystsmentioning

confidence: 99%

BCLA CLEAR - Orthokeratology

Vincent

Cho

Chan³

et al. 2021

Contact Lens and Anterior Eye

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103

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Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children.This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size.

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Microcystic corneal oedema associated with over-wear of decentred orthokeratology lenses during COVID-19 lockdown

Cited by 6 publications

References 10 publications

Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: A 2‐year randomised clinical trial

Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: A 2‐year randomised clinical trial

One‐year results of the Variation of Orthokeratology Lens Treatment Zone (VOLTZ) Study: a prospective randomised clinical trial

BCLA CLEAR - Orthokeratology

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