Clearing the Haze: Navigating Corneal Refractive Surgery in Patients with Posterior Polymorphous Corneal Dystrophy

Abstract Background To analyze whether corneal refractive surgery (CRS) is associated with the distribution of different accommodative dysfunctions (ADs) and binocular dysfunctions (BDs) in civilian pilots. A further aim was to analyze the percentages and visual symptoms associated with ADs and/or BDs in this population. Methods One hundred and eight civilian pilots who underwent CRS from January 2001 to July 2012 (age: 30.33 ± 4.60 years) were enrolled, the mean preoperative SE was − 1.51 ± 1.15 D (range: − 1.00- − 5.00 D). Ninety-nine emmetropic civilian pilots (age: 29.64 ± 3.77 years) who were age- and sex-matched to the CRS group were also enrolled. Refractive status, accommodative and binocular tests of each subject were performed. Visually related symptoms were quantified using the 19-item College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. The 19 items were summed to obtain visual symptom scores that might indicate visual dysfunctions. The chi-square test was used to analyze differences in percentages of ADs and/or BDs between the CRS and emmetropic groups. The Mann-Whitney U test was used to compare visual symptom scores between pilots with ADs and/or BDs and pilots with normal binocular vision. Results No significant difference was observed between the CRS and emmetropic groups in the overall prevalence of ADs and BDs (15.7% and 15.2% in the CRS and emmetropic groups, respectively; P = 0.185). ADs were present in 4.63% and 3.03% of the CRS and emmetropic group, respectively. BDs were observed in 11.1% and 12.1% of the CRS and emmetropic group, respectively, yielding no significant differences between the groups in the prevalence of ADs or BDs (AD: P = 0.094; BD: P = 0.105). Pilots with ADs and/or BDs had significantly more visual symptoms than pilots with normal binocular vision (p < 0.001). Conclusions CRS for civilian pilots with low-moderate myopia might not impact binocular functions. ADs and/or BDs commonly occur in both emmetropia pilots and pilots who undergo CRS, and pilots with ADs and/or BDs are associated with increased symptoms. This study confirms the importance of a full assessment of binocular visual functions in detecting and remedying these dysfunctions in this specific population.

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Corneal cross-linking for treatment of progressive keratoconus in a patient with Alport syndrome: A case report

European Journal of Ophthalmology ◽

10.1177/1120672121997672 ◽

2021 ◽

pp. 112067212199767

Author(s):

Iva Krolo ◽

Aida Kasumović ◽

Ivana Radman ◽

Pavao Pavić

Keyword(s):

Case Report ◽

Alport Syndrome ◽

Contact Lenses ◽

Corneal Dystrophy ◽

Clinical Findings ◽

Cross Linking ◽

Posterior Polymorphous Corneal Dystrophy ◽

One Year ◽

Corneal Tomography

Purpose: Ocular features of Alport syndrome include anterior lenticonus, posterior polymorphous corneal dystrophy, and fleck-and-dot retinopathy in most cases. Keratoconus in such patients has been rarely mentioned in previous studies. To our knowledge, this is the first report of corneal cross-linking for halting the progression of keratoconus in a patient with Alport syndrome. Case report: A 22-year-old male was referred for his initial corneal topography, after he was already prescribed with rigid gas-permeable contact lenses. Alport syndrome was diagnosed in his infancy and gene COL4A5 mutation was confirmed. Ophthalmological evaluation confirmed keratoconus. One-year follow-up showed a progression on his right eye and standard corneal cross-linking was performed. Stabilization of the disease marked by normalization in visual function and corneal tomography values was noticed 1 year after the procedure. Conclusions: When diagnosing ocular clinical findings of Alport syndrome, keratoconus should be considered. Standard corneal cross-linking protocol can halt its progression.

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Constitutive Laws for Biomechanical Modeling of Refractive Surgery

Journal of Biomechanical Engineering ◽

10.1115/1.2796033 ◽

1996 ◽

Vol 118 (4) ◽

pp. 473-481 ◽

Cited By ~ 122

Author(s):

Michael R. Bryant ◽

Peter J. McDonnell

Keyword(s):

Finite Element ◽

Material Properties ◽

Refractive Surgery ◽

Fiber Optic ◽

Transverse Isotropy ◽

Constitutive Laws ◽

Finite Element Models ◽

Corneal Refractive Surgery ◽

Best Fit ◽

Membrane Inflation

Membrane inflation tests were performed on fresh, intact human corneas using a fiber optic displacement probe to measure the apical displacements. Finite element models of each test were used to identify the material properties for four different constitutive laws commonly used to model corneal refractive surgery. Finite element models of radial keratotomy using the different best-fit constitutive laws were then compared. The results suggest that the nonlinearity in the response of the cornea is material rather than geometric, and that material nonlinearity is important for modeling refractive surgery. It was also found that linear transverse isotropy is incapable of representing the anisotropy that has been experimentally measured by others, and that a hyperelastic law is not suitable for modeling the stiffening response of the cornea.

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