Relationship between Axial Length and Corneo-Scleral Topography: A Preliminary Study

The main objective of the current study was to investigate further the relationship of the overall length of the eye with a great variety of anterior segment parameters, including scleral geometry. A total of 64 eyes of 32 participants with ages from 12 to 52 years were included in this prospective non-randomized single-center study. All participants underwent a complete eye examination, including an analysis of corneo-scleral shape with a Fourier-domain profilometer. A strong negative correlation was found between axial length and temporal-nasal ocular sagittal height difference for different chord lengths. For the right eye, a consistent and stable linear model was obtained to predict the axial length from the spherical equivalent, the corneal diameter, the high-order aberrations root mean square, and the minimum sagittal height for 13- and 14-mm chord. For the left eye, a model was obtained to predict the axial length from the spherical equivalent and the mean corneal curvature, including other parameters such as corneal diameter or high-order aberrations, depending on the chord length, considered for estimating the sagittal height values. More studies with larger samples are needed to confirm these preliminary outcomes.

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Spontaneous Scleral Perforation of an Anterior Chamber Intraocular Lens

Case Reports in Ophthalmology ◽

10.1159/000445880 ◽

2016 ◽

Vol 7 (1) ◽

pp. 249-252

Author(s):

Oriel Spierer ◽

Terrence P. O’Brien

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Intraocular Lens ◽

Anterior Segment ◽

Optical Coherence ◽

Chamber Length ◽

Good Visual Acuity ◽

Vertically Aligned ◽

Eye Examination ◽

The Right

A routine eye examination of a 69-year-old man revealed a scleral perforation of one of the haptics of the anterior chamber intraocular lens (AC IOL) which had been implanted many years ago. The patient was asymptomatic with good visual acuity. His history was negative for any trauma, eye rubbing, topical corticosteroid use, or autoimmune disease. The horizontal and vertical white-to-white diameters of the cornea in the right eye were 11.5 and 10.5 mm, respectively. Anterior segment optical coherence tomography showed the anterior chamber length to be 12.28 mm horizontally and 10.63 mm vertically. The patient underwent an IOL exchange, and the length of the explanted AC IOL was measured to be 12 mm. We speculate that the AC IOL, which was vertically aligned, was oversized. This case demonstrates the need for proper sizing and positioning of an AC IOL. In complex cases where AC IOL may be used, measuring the horizontal and vertical lengths of the anterior chamber by anterior segment optical coherence tomography prior to surgery may be useful.

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Posterior microphthalmos with pigmentary retinopathy

BMJ Case Reports ◽

10.1136/bcr-2020-234443 ◽

2020 ◽

Vol 13 (11) ◽

pp. e234443

Author(s):

Deepika C Parameswarappa ◽

Avantika Dogra

Keyword(s):

Low Vision ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Retinal Layer ◽

Slit Lamp ◽

Pigmentary Retinopathy ◽

Corrected Visual Acuity ◽

The Right ◽

Corneal Diameter ◽

Posterior Microphthalmos

We report a case of 19-year-old man with gradual diminution of vision in both eyes since childhood. His best-corrected visual acuity was 20/160, N16 in the right eye and 20/200, N16 in the left eye. Slit-lamp biomicroscopic examination revealed normal cornea, anterior segment, intraocular pressure and lens. Fundus of both eyes showed crowded optic disc with pigmentary changes. Ancillary tests were performed to aid in the diagnosis. A-scan ultrasound revealed short axial lengths with normal corneal diameter, anterior chamber depth and lens thickness. Optical coherence tomography of both eyes showed inner retinal layer folds. Electroretinogram of both eyes showed extinguished photopic as well as scoptopic responses. A diagnosis of posterior microphthalmos with pigmentary retinopathy was made. The patient was counselled regarding nature of the disease and the condition was managed with low vision aids.

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Refractive error and biometrics of anterior segment of eyes of healthy young university students in Japan

Scientific Reports ◽

10.1038/s41598-019-51920-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Kumiko Kato ◽

Mineo Kondo ◽

Maki Takeuchi ◽

Koji Hirano

Keyword(s):

University Students ◽

Anterior Chamber ◽

Refractive Error ◽

Axial Length ◽

Corneal Thickness ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Japanese University ◽

The Mean ◽

Corneal Diameter

Abstract To determine the parameters of the anterior segment of eyes that are significantly associated with the refractive error in healthy young Japanese university students. This was a cross-sectional observational study of 229 healthy Japanese university students (men: women,147:82) whose age ranged between 20 to 29 years. Univariate and multivariate linear regression analyses were performed to identify the factors that were significantly correlated with the refractive error. The independent variables included age, sex, axial length, anterior chamber depth, corneal diameter, curvature of anterior surface of cornea, and central corneal thickness. The mean refractive error (spherical equivalent) was −4.1 ± 2.7 diopters (D) with a range of −12.5 to +0.5 D, and the mean axial length was 25.4 ± 1.3 mm with a range of 22.4 to 29.0 mm. Pearson univariate correlation analysis found that the refractive error was significantly and negatively correlated with the axial length (R = −0.82, P < 0.001), deeper anterior chamber (R = −0.30, P < 0.001), and larger corneal diameter (R = −0.21, P = 0.001). Multiple regression analysis showed that the refractive error was significantly associated with a longer axial length (P < 0.001), a deeper anterior chamber (P < 0.001), and a flatter corneal curvature (P < 0.001).The biometric values of the anterior segment of the eyes should make the eye more hyperopic which would reduce the myopia-inducing lengthening of the axial length.

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Eyes of Aniso-Axial Length Individuals Share Generally Similar Corneal Biometrics with Normal Eyes in Cataract Population

Journal of Ophthalmology ◽

10.1155/2020/4760978 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Min Zhang ◽

Tianhui Chen ◽

Michael Deng ◽

Jiahui Chen ◽

Qinghe Jing ◽

...

Keyword(s):

Axial Length ◽

Case Series ◽

High Order ◽

Corneal Astigmatism ◽

Retrospective Case ◽

Corneal Aberrations ◽

Length Group ◽

Cataract Patients ◽

High Order Aberrations ◽

Anterior Corneal Astigmatism

Aims. To determine the characteristics of corneal biometrics in eyes from aniso-axial length cataract patients compared with eyes from non-aniso-axial length individuals. Methods. This is a retrospective case series. Cataract patients with preoperative binocular measurements were recruited. A binocular axial difference of ≥1 mm was considered to indicate aniso-axial length. The anterior segmental biometrics were measured using Pentacam HR (Oculus, Wetzlar, Germany) and IOLMaster 500 (Carl Zeiss Meditec, Jena, Germany). Comparisons of biometrics were made among 4 eye conditions: the longer eyes from aniso-axial length patients, the shorter eyes from aniso-axial length patients, the longer eyes from non-aniso-axial length patients, and the shorter eyes from non-aniso-axial length patients. The aniso-axial length eyes were also stratified into 8 subgroups with axial length (AL) increments of 1 mm, and the biometrics of the subgroups were compared. Results. There was smaller anterior corneal astigmatism in the shorter aniso-axial length group than those in the longer aniso-axial length group (1.01 ± 0.70 D vs 1.12 ± 0.76 D, P = 0.031 ). The longer aniso-axial length eyes had greater anterior corneal steep curvature (44.13 ± 1.69 D vs 43.87 ± 1.69 D, P = 0.009 ) and anterior corneal astigmatism (1.12 ± 0.76 D vs 1.02 ± 0.69 D, P = 0.023 ) compared with longer non-aniso-axial length subjects. Other corneal biometrics were similar between the aniso-axial length eyes and the non-aniso-axial length eyes. In the longer aniso-axial length group, the posterior corneal aberrations of eyes in the ≥5 mm subgroups were greater than those in the <5 mm subgroups (0.879 ± 0.183 μm vs 0.768 ± 0.178 μm for total aberrations, P < 0.001 ; 0.228 ± 0.086 μm vs 0.196 ± 0.043 μm for high-order aberrations, P = 0.036 ; 0.847 ± 0.173 μm vs 0.741 ± 0.179 μm for low-order aberrations, P = 0.001 ). Conclusion. Eyes of aniso-axial length individuals share generally similar corneal biometrics with normal eyes in cataract population. Anterior corneal astigmatism of the longer eyes from the aniso-axial length cataract patients was higher than that of the longer eyes from the non-aniso-axial length individuals. Total posterior corneal aberrations of the longer aniso-axial length eyes increased when the binocular axial difference was over 5 mm.

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Axial Length and White to White Corneal Diameter in Eyes with Keratoconus

QJM ◽

10.1093/qjmed/hcab109.028 ◽

2021 ◽

Vol 114 (Supplement_1) ◽

Author(s):

Omnia Talaat Abd elwahab ◽

Dina Ezzat Mansour ◽

Maged Maher Salib Roshdy ◽

Ahmed Taha Ismail ◽

Omnia Talaat Abd elwahab

Keyword(s):

Axial Length ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Normal Group ◽

Control Group ◽

Spherical Equivalent ◽

Lens Thickness ◽

Significant Difference ◽

The Mean ◽

Corneal Diameter

Abstract Objective To study the axial length (AL) and white to white (WTW) corneal diameter in keratoconus (KC) eyes and compare them to normal eyes. Methods Sixty-three eyes of 53 patients were included in this cross-sectional observational study divided into KC group comprised of 28 eyes of 18 patients and control group comprised of 35 eyes of 35 patients based on clinical and tomographic findings. All subjects were examined using rotating Scheimpflug corneal tomography (Pentacam HR; Oculyzer II) for central corneal thickness (CCT), thinnest corneal thickness (TCT), keratometric values, anterior chamber depth (ACD) and lens thickness, and by optical biometry (IOLMaster 500) for axial length (AL) measurements. Vitreous cavity length (VCL) was calculated by subtracting the values of CCT, ACD (internal), and lens thickness from the AL. White to white (WTW) corneal diameter was measured using Placido-based tomography (Topolyzer VARIO). Results The mean age was 31.27±8.65 years(30.39 ± 9.31) in the KC group and .(31.74 ± 8.38) in the non KC group. The KC group included 28 eyes their mean spherical equivalent (SE) was -3.16 ± 2.42 and the control group 35 healthy eyes including 23 ametropic eyes with mean spherical equivalent (SE) (-3.95±4.50 D) and 12 emmetropic eyes with mean SE (-0.19±0.40 D). The mean VCL was significantly greater in normal eyes (17.45 ±1.34 mm) compared with KC (16.77±1.18 mm) (P = 0.037), while the mean ACD (internal) was significantly greater in KC eyes compared to normal (P = 0.020) and the lens thickness showed no statistically significant difference. The greater VCL in the normal group was compensated by the greater ACD in the KC group causing the total AL to have no statistically significant difference (normal eyes =24.44 ±1.38 mm and KC eyes= 24.21 ±1.31 mm) (P = 0.513). There was no statistically significant difference in the WTW corneal diameter between KC and normal eyes (11.81 ±0.35 mm in the normal group compared to 11.79 ±0.35 mm in the KC group) (P = 0.835). Conclusion VCL was significantly greater in normal eyes compared with those eyes with KC. AL and WTW showed no difference between the two groups.

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Wavefront aberrations induced from biomechanical effects after customized myopic laser refractive surgery in finite element model

10.21203/rs.3.rs-189830/v1 ◽

2021 ◽

Author(s):

Ruirui Du ◽

Lihua Fang ◽

Weijian Peng ◽

Ruizhi Yang ◽

Shifeng Nie ◽

...

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Refractive Surgery ◽

Element Model ◽

High Order ◽

Spherical Equivalent ◽

Wavefront Aberrations ◽

Material Parameters ◽

Ablation Profile ◽

High Order Aberrations

Abstract Purpose A customized myopic refractive surgery was simulated by establishing a finite element model of the human eye,after which we studied the wavefront aberrations induced by biomechanical effects and ablation profile after wavefront-guided LASIK surgery. Methods Thirty myopia patients (i.e., 60 eyes) without other eye diseases were selected. Their ages, preoperative spherical equivalent, astigmatism, and wavefront aberration were then obtained, in addition to the mean spherical equivalent error range − 4 to -8D. Afterward, wavefront-guided customized LASIK surgery was simulated by establishing a finite element eye model, followed by the analysis of the wavefront aberrations induced by the surface displacement from corneal biomechanical effects, as well as customized ablation profile. Finally, the preoperative and induced aberrations were statistically analyzed. Results Comatic aberrations were the main wavefront abnormality induced by biomechanical effects, and the wavefront aberrations induced by the ablation profile mainly included coma and secondary-coma, as well as sphere and secondary-sphere aberrations. Overall, the total high-order aberrations (tHOAs), total coma (C31), and sphere () increased after wavefront-guided customized LASIK surgery. According to our correlation analyses, coma, sphere, and total high-order aberrations were significantly correlated with decentration. Additionally, the material parameters of ocular tissue were found to affect the postoperative wavefront aberrations. When the material parameters of the sclera remained constant but those of cornea increased, the induced wavefront aberrations were reduced. Conclusion All biomechanical effects of cornea and ablation profile had significant effects on postoperative wavefront aberrations after customized LASIK refractive surgery; however, the effects of the ablation profile were more notorious.Additionally,the characteristics of biomechanical materials have influence on the clinical correction effect.

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Hyperopic anisometropia with a shorter axial length ipsilateral to the ptotic eye in children with congenital ptosis

BMC Ophthalmology ◽

10.1186/s12886-021-02126-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Satoshi Ueki ◽

Yuji Suzuki ◽

Megumi Kiyokawa ◽

Takako Hanyu ◽

Takeo Fukuchi

Keyword(s):

Axial Length ◽

Clinical Characteristics ◽

Visual Development ◽

Spherical Equivalent ◽

Congenital Ptosis ◽

High Incidence ◽

Dental Hospital ◽

Refractive Correction ◽

The Difference ◽

The Right

Abstract Background To investigate the clinical characteristics of children with congenital ptosis, with particular attention given to the incidence of anisometropia, and the difference in axial length (AL) between the right and left eyes. Methods The medical charts of 55 patients with congenital ptosis at Niigata University Medical and Dental Hospital were retrospectively analyzed. Clinical characteristics, including age, cycloplegic refraction, AL, and the presence of amblyopia and its causes were analyzed. Results Age at the initial visit was 16 ± 20 (mean ± standard deviation, the same applies below) months. Of the 49 patients whose cycloplegic refraction was measured, hyperopic anisometropia, defined as ≥ one-diopter difference in spherical equivalent (SE), was observed in 1/11, 9/27 and 5/11 patients with bilateral, right, and left ptosis, respectively. Among 14/38 patients with hyperopic anisometropia involving unilateral ptosis, 13 demonstrated a larger SE in the ptotic eye than in the non-ptotic eye. The inter-eye difference in AL (AL of the ptotic eye minus that of the non-ptotic eye) in six patients with unilateral ptosis and hyperopic anisometropia ipsilateral to the ptotic eye (-0.29 ± 0.40 mm) was significantly smaller than that in three patients with unilateral ptosis and no hyperopic anisometropia (0.38 ± 0.29 mm). Conclusions At our institute, children with congenital ptosis had a high incidence of hyperopic anisometropia ipsilateral to the ptotic eye. Furthermore, this condition was associated with a shorter axial length. These results indicate that refractive correction for hyperopic anisometropia is important for proper visual development in children with congenital ptosis.

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