scholarly journals Retinal contour modelling to reproduce two-dimensional peripheral spherical equivalent refraction

2021 ◽  
Author(s):  
Qing Li ◽  
Fengzhou Fang
Keyword(s):  
Two Dimensional ◽  
Spherical Equivalent ◽  
Spherical Equivalent Refraction

scholarly journals Refractive outcome of cataract surgery in eyes filled with silicone oil

2019 ◽  
Author(s):  
Piotr Kanclerz ◽  
Christoph Leisser ◽  
Andrzej Grzybowski ◽  
Paweł Lipowski
Keyword(s):  
Cataract Surgery ◽  
Silicone Oil ◽  
Spherical Equivalent ◽  
Refractive Outcome ◽  
Spherical Equivalent Refraction ◽  
Cataract Development ◽  
Oil Injection ◽  
Phacoemulsification Cataract Surgery

Abstract Background Cataract development is common in phakic eyes filled with silicone oil (SO), necessitating subsequent cataract removal. This study evaluated the refractive outcome in eyes filled with SO undergoing phacoemulsification cataract surgery (PCS). Methods This retrospective study evaluated patients with SO tamponade who were scheduled for PCS. Results Subjects (n=26) were followed-up for 29.5 ± 13.9 months after cataract surgery. The median spherical equivalent refraction (SER) was +5.3 D (interquartile range [IQR] +2.9 to +6.7) before PCS, and +3.4 D (IQR +2.0 to +4.4) after PCS. Within the follow-up period retinal reattachment after SO removal was achieved in 15 out of 26 eyes (57.7%). In 13 eyes assessment of refraction after SO-removal was possible, and showed a myopic shift of -4.6 D (IQR -2.9 to -7.3) in the SER. After SO removal, 5 of 13 eyes (38.5%) were within ±1.0 D of the target refraction, while 9 out of 13 eyes (69.2%) were within ±2.0 D. Conclusions The refractive outcome after PCS for eyes filled with SO is less predictable than that for normal eyes. Some of the eyes undergoing silicone oil injection may require long-term tamponade.

Clinical outcomes of small incision lenticule extraction versus advanced surface ablation in low myopia

2019 ◽  
Vol 30 (6) ◽  
pp. 1278-1286 ◽  
Author(s):  
Suphi Taneri ◽  
Saskia Kießler ◽  
Anika Rost ◽  
Tim Schultz ◽  
H Burkhard Dick
Keyword(s):  
Visual Acuity ◽  
Spherical Equivalent ◽  
Small Incision Lenticule Extraction ◽  
Distance Visual Acuity ◽  
Small Incision ◽  
Surface Ablation ◽  
Uncorrected Distance Visual Acuity ◽  
Corrected Distance Visual Acuity ◽  
Spherical Equivalent Refraction ◽  
Lenticule Extraction

Purpose: To compare the visual and refractive outcomes of small incision lenticule extraction and advanced surface ablation for low myopia or myopic astigmatism. Methods: Retrospective, observational case series of our first 50 consecutive small incision lenticule extraction patients compared to refraction-matched 50 advanced surface ablation treatments with attempted spherical equivalent correction ⩽−3.5 D, astigmatism ⩽−1.5 D, and corrected distance visual acuity of 1.0 (decimal scale) or better. Only one eye per patient was included. Results: Small incision lenticule extraction: mean attempted spherical equivalent correction was −2.80 ± 0.63 D. Uncorrected distance visual acuity was 0.85 and 1.0 at days 1 and 5, respectively. At 3 months, mean spherical equivalent refraction was 0.02 ± 0.32 D (range: −0.5 to +0.75 D), mean cylinder was −0.24 ± 0.21 D (range: 0 to −0.75 D), mean uncorrected distance visual acuity was 1.27, mean efficacy index was 0.96, and mean safety index was 1.05. Uncorrected distance visual acuity was same or better than corrected distance visual acuity in 96%, astigmatism ⩽0.5 D in 98% and ⩽1 D in 100% of eyes, respectively. Advanced surface ablation: mean attempted spherical equivalent correction was −2.75 ± 0.5 D. Uncorrected distance visual acuity was 0.72 and 0.61 at days 1 and 5, respectively. At 3 months, mean spherical equivalent refraction was 0.22 ± 0.32 D, mean cylinder was −0.27 ± 0.27 D, mean uncorrected distance visual acuity was 1.21, mean efficacy index was 1.03, and mean safety index was 1.08. Conclusion: Small incision lenticule extraction for low myopia was found to be safe and effective with outcomes at 3 months similar to those obtained with advanced surface ablation while offering a quicker visual recovery.

scholarly journals The Role of Axial Length-Corneal Radius of Curvature Ratio in Refractive State Categorization in a Nigerian Population

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Eghosasere Iyamu ◽  
Joy Iyamu ◽  
Christian Izuchukwu Obiakor
Keyword(s):  
Axial Length ◽  
Inverse Correlation ◽  
Radius Of Curvature ◽  
Spherical Equivalent ◽  
Refractive State ◽  
Spherical Equivalent Refraction ◽  
Nigerian Population ◽  
Corneal Radius ◽  
The Mean

The aim of this study was to investigate the association of axial length (AL)/corneal radius of curvature (CRC) ratio (AL/CRC) with spherical equivalent refractive state (SER) in young adults. A total of seventy () subjects consisting of 31 males and 39 females participated in this study. Subjects were categorized into emmetropia, hyperopia and myopia using the spherical equivalent refraction. The axial length was measured with I-2100 A-Scan ultrasonography/Biometer (CIMA Technology, USA), the corneal radius of curvature with Bausch & Lomb H-135A (Bausch & Lomb Corp., USA), and the refractive state by static retinoscopy and subjective refraction. The mean AL, CRC and AL/CRC ratio of all subjects were 23.74 ± 0.70 mm, 7.84 ± 0.19 mm, and 3.03 ± 0.14, respectively. Myopes had significantly longer AL, steeper CRC and higher AL/CRC ratio than the emmetropes and hyperopes. There was statistically significant inverse correlation between AL and CRC (, ), SER (, ), and between SER and AL/CRC (, ). A significant positive correlation was found between CRC and SER (, ). The categorization of the refractive state of an individual is better done by using the AL/CRC ratio index.

scholarly journals Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Isabel Cacho ◽  
Juan Sanchez-Naves ◽  
Laura Batres ◽  
Jesús Pintor ◽  
Gonzalo Carracedo
Keyword(s):  
Intraocular Pressure ◽  
Refractive Surgery ◽  
Corneal Thickness ◽  
Laser In Situ Keratomileusis ◽  
Spherical Equivalent ◽  
Transpalpebral Tonometry ◽  
Spherical Equivalent Refraction ◽  
Before And After ◽  
Noncontact Tonometry

Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers.Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers.Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (p<0.05). However, no significant differences were found (p>0.05) for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery (p<0.05) but no statistical differences were found in SCT (p=0.08). Correlations between pre- and postsurgery were found for all tonometers used, withp=0.001andr=0.434for the air pulse tonometer,p=0.008andr=0.355for Perkins, andp<0.001andr=0.637for Diaton.Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment.

EVALUATION OF THE EFFECTS OF ORTHOKERATOLOGY ON MYOPIA, ASTIGMATISM IN DA NANG FARGO ORTHO-K CENTER

2018 ◽  
Vol 8 (4) ◽  
pp. 70-75
Author(s):  
Khoi Hoang Huu
Keyword(s):  
Visual Acuity ◽  
Prospective Study ◽  
Key Words ◽  
Case Studies ◽  
Outcome Evaluation ◽  
Spherical Equivalent ◽  
Safe Treatment ◽  
Spherical Equivalent Refraction ◽  
Pre Treatment ◽  
A Prospective Study

Objectives: To evaluate the effects of orthokeratology (Ortho-K) on myopia, astigmatism and identify complications during applying the treatment. Methods: This is a prospective study accompanied with a series of case studies and outcome evaluation of 118 eyes of 60 patients who were diagnosed for myopia, astigmatism and were indicated wearing overnight Ortho-K lenses during the time from June 2017 to June 2018. Results: 118 eyes were prescribed wearing overnight Ortho-K lenses and their results were reported as follow: Visiual acuity ≥ 8/10 before the treatment was 1.7%, after one day of the treatment it increased to 3.4%, after 1 week it was 34.7%, after 1 month it was 71.2%, after 3 month it was 87.1% and after 6 months it accounted for 94.7%; Mean spherical equivalent refraction pre-treatment was -4.03D ± 1.70D, after 6 months of the treatment it reduced to - 0.38D ± 0.45D; Residual refraction after 6 months of the treatment ≤ 1.00D accounted for 96.5%; After 1 month of the treatment, 09 eyes (7.6%) were diagnosed for mild keratitis and 109 eyes (92.4%) had normal cornea after the treatment. Conclusions: Our results suggest that orthokeratology is a highly effective and safe treatment for correcting visual acuity in myopic and astigmatic patients. Key words: Myopia, astigmatism, orthokeratology

scholarly journals Multifocal Toric Intraocular Lens for Traumatic Cataract in a Child

2016 ◽  
Vol 7 (3) ◽  
pp. 481-485 ◽  
Author(s):  
Yanfeng Zeng ◽  
Licheng Fan ◽  
Peirong Lu
Keyword(s):  
Intraocular Lens ◽  
Primary Outcome ◽  
Corneal Astigmatism ◽  
Spherical Equivalent ◽  
Traumatic Cataract ◽  
Toric Intraocular Lens ◽  
Near Vision ◽  
Uncorrected Distance Visual Acuity ◽  
Spherical Equivalent Refraction ◽  
Optical Phenomena

A child suffering from traumatic cataract and corneal astigmatism of 2.14 D had a phacoemulsification operation and implantation of a ReSTOR Toric intraocular lens (IOL) to correct the astigmatism. The primary outcome measurements were the uncorrected distance visual acuity (UDVA), uncorrected near vision at 40 cm, intraocular pressure, spherical equivalent refraction, residual astigmatism, corneal astigmatism, presence of unusual optical phenomena, and use of spectacles. At 7 months postoperatively, UDVA was maintained between 16/20 and 24/20, near vision was between J1 and J3, residual spherical refraction was 0–0.37 D, and residual refractive cylinder was between 0 and 0.67 D. A multifocal toric IOL can provide the possibility of satisfactory vision for both distant and near conditions without the use of spectacles to meet children’s needs when studying and doing sports. Additionally, binocular vision can be reconstructed. This intervention, therefore, seems to be a satisfactory alternative.

scholarly journals Influence of Refractive Condition on Retinal Vasculature Complexity in Younger Subjects

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Mohd Zulfaezal Che Azemin ◽  
Norsyazwani Mohamad Daud ◽  
Fadilah Ab Hamid ◽  
Ilyanoon Zahari ◽  
Abdul Halim Sapuan
Keyword(s):  
Fractal Dimension ◽  
High Myopia ◽  
Computer Software ◽  
Retinal Vessel ◽  
Retinal Vasculature ◽  
Spherical Equivalent ◽  
Standardized Protocol ◽  
Significant Difference ◽  
Spherical Equivalent Refraction ◽  
Retinal Vessel Density

Objective. The aim of this study was to compare the retinal vasculature complexity between emmetropia, and myopia in younger subjects.Methods. A total of 82 patients (24.12±1. 25years) with two types of refractive conditions, myopia and emmetropia were enrolled in this study. Refraction data were converted to spherical equivalent refraction. These retinal images (right eyes) were obtained from NAVIS Lite Image Filing System and the vasculature complexity was measured by fractal dimension (Df), quantified using a computer software following a standardized protocol.Results. There was a significant difference (P < 0.05) in the value ofDfbetween emmetropic (1.5666 ± 0.0160) and myopic (1.5588 ± 0.0142) groups. A positive correlation (rho = 0.260,P < 0.05) between theDfand the spherical equivalent refraction was detected in this study. Using a linear model, it was estimated that 6.7% of the variation inDfcould be explained by spherical equivalent refraction.Conclusions. This study provides valuable findings about the effect of moderate to high myopia on the fractal dimension of the retinal vasculature network. These results show that myopic refraction in younger subjects was associated with a decrease inDf, suggesting a loss of retinal vessel density with moderate to high myopia.

Astigmatism and its components in 12-year-old Chinese children: the Anyang Childhood Eye Study

2018 ◽  
Vol 103 (6) ◽  
pp. 768-774 ◽  
Author(s):  
He Li ◽  
Shi-Ming Li ◽  
Luo-Ru Liu ◽  
Ya-Zhou Ji ◽  
Meng-Tian Kang ◽  
...  
Keyword(s):  
Study Data ◽  
Chinese Children ◽  
Refractive Errors ◽  
Spherical Equivalent ◽  
Corneal Curvature ◽  
Old Chinese ◽  
Spherical Equivalent Refraction

PurposeTo determine prevalence of refractive (RA), corneal (CA) and internal astigmatism (IA), including variation with gender and spherical equivalent refraction (SE), in a population of 12-year-old Chinese children.MethodsA total of 1783 students with a mean age of 12.7 years (range 10.0–15.6 years) completed comprehensive eye examinations in the Anyang Childhood Eye Study. Data of cycloplegic refraction and corneal curvature were analysed.ResultsPrevalences of RA, CA and IA ≥1.0 D were 17.4% (95%CI 15.6% to 19.2%), 52.8% (50.5% to 55.1%)%) and 20.9% (19.0% to 22.8%), respectively. With different limits of astigmatism axes classification, including ±15°, ±20° and ±30°, RA and CA axes were mainly ‘with-the-rule’ (WTR) (ie, correcting axis of negative cylinders at or near 180°), while those for IA axes were mainly ‘against-the-rule’ (ATR) (ie, correcting axis of negative cylinders at or near 90°). RA was not different between the genders, but girls had higher prevalence and greater means of CA and IA. RA and CA increased in students with higher ametropia (more myopia and more hyperopia) and were the highest in a high myopic group (SE≤−6 D), while IA was stable across refraction groups. Children with RA higher than 0.50 D were more likely to have lens corrections (51%, 57%, 61% and 69% for magnitudes of ≥0.50 D, ≥0.75 D, ≥1.0 D and ≥1.5 D, respectively).ConclusionsPrevalence of RA in the Chinese 12-year-old children was relatively high compared with other studies. RA and CA had mainly ‘WTR’ astigmatism, while IA was mainly ATR and partially compensated for CA. Girls had greater means and prevalences of CA and IA than did boys. Both RA and CA, but not IA, increased with refractive errors away from emmetropia.

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