Axial Length in Keratoconus

Lanier, Jeffrey Day; Bullington, Robert H.; Prager, Thomas C.

doi:10.1097/00003226-199205000-00011

Cited by 34 publications

(6 citation statements)

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“…Axial length of the eye is a potential factor that can alter HCVA estimates due to a difference in magnification on the retina. KC eyes are reported to have longer axial lengths than emmetropes (Lanier, Bullington, & Prager, 1992), which would translate to a higher magnification of the visual stimulus on the retina. Accordingly, the difference in HCVA between KC and normal eyes, by accounting for this magnification, will be further increased.…”

Section: Discussionmentioning

confidence: 99%

Visual performance after correcting higher order aberrations in keratoconic eyes

Sabesan

Yoon

2009

Journal of Vision

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Keratoconic eyes are affected by an irregular optical blur induced by significant magnitude of higher order aberrations (HOAs). Although it is expected that correction of ocular aberrations leads to an improvement in visual performance, keratoconic eyes might not achieve the visual benefit predicted by optical theory because of long-term adaptation to poor retinal image quality. To investigate this, an adaptive optics (AO) system equipped with a large-stroke deformable mirror and a Shack–Hartmann wavefront sensor was used to correct the aberrations and measure high contrast tumbling E visual acuity (HCVA) in 8 keratoconic eyes. Eight normal eyes were employed as control. Aberrations were dynamically corrected with closed-loop AO during visual acuity testing, with residual root-mean-square error of around 0.1 μm in both groups over 6-mm pupil (p = 0.11). With AO correction, the HCVA in logMAR was −0.26 ± 0.063 in normal eyes, and in keratoconic eyes, it was −0.07 ± 0.051 (p = 0.0001) for the same pupil size. There was no correlation in the AO-corrected HCVA for normals with the magnitudes of their native HOA. However, within keratoconic eyes, poorer AO-corrected HCVA was observed with an increase of the native magnitudes of HOA (R2 = 0.67). This may indicate that long-term visual experience with poor retinal image quality, induced by HOA, may restrict the visual benefit achievable immediately after correction in keratoconic eyes.

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Section: Discussionmentioning

confidence: 99%

Visual performance after correcting higher order aberrations in keratoconic eyes

Sabesan

Yoon

2009

Journal of Vision

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“…However, when the anterior lens-to-retina length is less than 20.19 mm, a reduction of donor size could result in significant postoperative hyperopia. 153 – 157 …”

Section: Resultsmentioning

confidence: 99%

Keratoconus: exploring fundamentals and future perspectives – a comprehensive systematic review

Niazi,

Gatzioufas,

Doroodgar

et al. 2024

Ophthalmol Eye Dis

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Background: New developments in artificial intelligence, particularly with promising results in early detection and management of keratoconus, have favorably altered the natural history of the disease over the last few decades. Features of artificial intelligence in different machine such as anterior segment optical coherence tomography, and femtosecond laser technique have improved safety, precision, effectiveness, and predictability of treatment modalities of keratoconus (from contact lenses to keratoplasty techniques). These options ingrained in artificial intelligence are already underway and allow ophthalmologist to approach disease in the most non-invasive way. Objectives: This study comprehensively describes all of the treatment modalities of keratoconus considering machine learning strategies. Design: A multidimensional comprehensive systematic narrative review. Data sources and methods: A comprehensive search was done in the five main electronic databases (PubMed, Scopus, Web of Science, Embase, and Cochrane), without language and time or type of study restrictions. Afterward, eligible articles were selected by screening the titles and abstracts based on main mesh keywords. For potentially eligible articles, the full text was also reviewed. Results: Artificial intelligence demonstrates promise in keratoconus diagnosis and clinical management, spanning early detection (especially in subclinical cases), preoperative screening, postoperative ectasia prediction after keratorefractive surgery, and guiding surgical decisions. The majority of studies employed a solitary machine learning algorithm, whereas minor studies assessed multiple algorithms that evaluated the association of various keratoconus staging and management strategies. Last but not least, AI has proven effective in guiding the implantation of intracorneal ring segments in keratoconus corneas and predicting surgical outcomes. Conclusion: The efficient and widespread clinical translation of machine learning models in keratoconus management is a crucial goal of potential future approaches to better visual performance in keratoconus patients. Trial registration: The article has been registered through PROSPERO, an international database of prospectively registered systematic reviews, with the ID: CRD42022319338

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“…Tüm Bunun yanında keratokonus ve emetrop gözlerde aksiyel uzunluk farkı olmadığını gösteren çalışmalarda mevcuttur. 9,22 Bu iki çalışmada ortalama aksiyel uzunluk 24,39 ve 24,01 mm olmasına rağmen karşılaştırdıkları emetrop grupta ortalama aksiyel uzunluk 24,2 mm olduğu için fark saptanmamıştır. Bizim çalışmamızda ortalama AU, keratokonusta 23,83±0,72 mm, kontrol grubunda 22,81±0,66 mm idi (p=0,001).…”

Section: Gereç Ve Yöntemunclassified

Keratoconus Association with Axial Myopia

...

2012

tjo

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Amaç: Keratokonus ve aksiyel miyopi arasındaki ilişkiyi incelemek ve ayrıca normal ve keratokonuslu gözlerde ultrason biyometri kullanarak ön kamara derinliği, aksiyel uzunluğu ve arka segment uzunluklarını karşılaştırmak. Ge reç ve Yön tem: Bu çalışmada, 44 keratokonuslu ve 44 emetropik gözün refraksiyon ve oküler biyometrileri prospektif olarak değerlendirildi. Tüm olguların, ultrason biyometri ile aksiyel uzunluk ve ön kamara derinliği ölçümleri yapıldı. İstatiksel yöntemler, iki grubu karşılaştırmak ve herhangi bir ilişki olup olmadığını tespit etmek için kullanıldı. So nuç lar: Aksiyel uzunluk, keratokonuslu grupta emetrop kontrol grubuna göre istatiksel olarak anlamlı bir biçimde daha uzundu. Ortalama aksiyel uzunluk, keratokonusta 23,83±0,72 mm ve emetropik grupta 22,81±0,66 mm idi (p=0,001). Ortalama arka segment uzunluğu, keratokonusta 19,96±0,41 mm ve emetropik grupta 19,63±0,54 mm idi (p=0,002). Keratokonuslu grup için ortalama keratometri, sferik eşdeğer ve görme keskinliği ile korele idi. Tar t›fl ma: Keratokonuslu gözler, emetrop gözlerden daha uzun ortalama aksiyel uzunluk ve arka segment uzunluğuna sahipti. Bu keratokonus ve aksiyel uzunluk arasında istatiksel bir ilişki olduğunu düşündürmektedir. (Turk J Ophthalmol 2012; 42: 246-8) Anah tar Ke li me ler: Keratokonus, aksiyel uzunluk, ön kamara derinliği, ultrason biyometri Sum maryPur po se: To study the relationship between keratoconus and axial myopia and also to compare anterior chamber depth, axial length and posterior segment length in normal eyes and keratoconic eyes using ultrasound biometry. Ma te ri al and Met hod: In this study, refraction and ocular biometry in 44 keratoconus eyes and 44 emmetropic eyes were evaluated prospectively. All subjects underwent axial length and anterior chamber depth measurement by ultrasound biometry. Statistical methods were employed to compare the two groups and to ascertain whether any associations exist. Re sults: The axial length was significantly longer in the keratoconic group than in the emmetropic control group in a statistically significant fashion. The mean axial lengths in the keratoconic and emmetropic groups were 23.83±0.72 and 22.81±0.66 mm, respectively (p=0.001). The mean posterior segment length in the keratoconic group was 19.96±0.41 vs. 19.63±0.54 mm in the emmetropic group (p=0.002). The mean keratometry for the keratoconic group correlated with spherical equivalence and visual acuity. Dis cus si on: Keratoconic eyes have on average longer axial lengths and posterior segment lengths than emmetropic eyes. This finding suggests a statistical relationship between keratoconus and axial myopia. (Turk J Ophthalmol 2012; 42: 246-8)

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Axial Length in Keratoconus

Cited by 34 publications

References 0 publications

Visual performance after correcting higher order aberrations in keratoconic eyes

Visual performance after correcting higher order aberrations in keratoconic eyes

Keratoconus: exploring fundamentals and future perspectives – a comprehensive systematic review

Keratoconus Association with Axial Myopia

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