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1.
Transl Vis Sci Technol ; 13(6): 2, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38837172

ABSTRACT

Purpose: The purpose of this study was to develop a simplified method to approximate constants minimizing the standard deviation (SD) and the root mean square (RMS) of the prediction error in single-optimized intraocular lens (IOL) power calculation formulas. Methods: The study introduces analytical formulas to determine the optimal constant value for minimizing SD and RMS in single-optimized IOL power calculation formulas. These formulas were tested against various datasets containing biometric measurements from cataractous populations and included 10,330 eyes and 4 different IOL models. The study evaluated the effectiveness of the proposed method by comparing the outcomes with those obtained using traditional reference methods. Results: In optimizing IOL constants, minor differences between reference and estimated A-constants were found, with the maximum deviation at -0.086 (SD, SRK/T, and Vivinex) and -0.003 (RMS, PEARL DGS, and Vivinex). The largest discrepancy for third-generation formulas was -0.027 mm (SD, Haigis, and Vivinex) and 0.002 mm (RMS, Hoffer Q, and PCB00/SN60WF). Maximum RMS differences were -0.021 and +0.021, both involving Hoffer Q. Post-minimization, the largest mean prediction error was 0.726 diopters (D; SD) and 0.043 D (RMS), with the highest SD and RMS after adjustments at 0.529 D and 0.875 D, respectively, indicating effective minimization strategies. Conclusions: The study simplifies the process of minimizing SD and RMS in single-optimized IOL power predictions, offering a valuable tool for clinicians. However, it also underscores the complexity of achieving balanced optimization and suggests the need for further research in this area. Translational Relevance: The study presents a novel, clinically practical approach for optimizing IOL power calculations.


Subject(s)
Lenses, Intraocular , Optics and Photonics , Humans , Optics and Photonics/methods , Biometry/methods , Refraction, Ocular/physiology , Female , Male , Lens Implantation, Intraocular/methods , Aged , Visual Acuity/physiology , Middle Aged
2.
Article in English | MEDLINE | ID: mdl-38758195

ABSTRACT

PURPOSE: To evaluate visual outcomes of high hyperopic LASIK, using corneal aspherization to control the induced spherical aberration. SETTING: Fondation Ophtalmologique Adolphe de Rothschild. DESIGN: Prospective interventional case series. METHODS: Prospective interventional study of consecutive high hyperopes (≥+3D of Spherical Equivalent SE) undergoing LASIK with the WaveLight FS200 femtosecond and EX500 excimer laser platform. An aspheric ablation profile (planned change in corneal asphericity ΔQ = +0.2) was delivered using the Custom-Q nomogram (Alcon Laboratories, Inc., Fort Worth, TX) on an optical zone of ≥ 6.5mm centered near the corneal vertex. Uncorrected and best-corrected distance visual acuity (UDVA-BDVA), as well as changes in SE, corneal asphericity (ΔQ) and Higher order aberrations (HOAs), were analyzed preoperatively and on day1, 1, 3, 6, and 12 months. RESULTS: 117 eyes of 63 patients, (mean age of 30.1 ± 5.6 years), were included. Preoperatively and at 12 months postoperatively, the mean SE was 5.1 ± 1.1 D and 0.00 ± 0.7 D, respectively. 88% of eyes achieved 0 Log Mar or better UDVA at 12 months. One month after surgery, there was a statistically significant induction of positive spherical aberration decreasing progressively and significantly until the last visit (Preop SA4 = 0.09 ± 0.11 µm, Day 1 SA4 = 0.30 ± 0.32 µm, 12 Months SA4 = 0.08 ± 0.21 µm, p=0.056). Two eyes needed enhancement at 12 months. CONCLUSION: LASIK for high levels of hyperopia showed good outcomes mainly due to aspheric-customized ablation profile with a change of ΔQ = +0.2 in corneal asphericity.

3.
Can J Ophthalmol ; 59(2): 67-72, 2024 Apr.
Article in English | MEDLINE | ID: mdl-36627103

ABSTRACT

OBJECTIVE: Zonular dialysis (ZD), referred to as the presence of a deficient zonular support for the lenticular capsule, might be the result of several causes and be detected only at the time of cataract surgery. The aim of this study was to evaluate pre-, intra-, and postoperative features of eyes with ZD regardless of the etiology detected during cataract surgery. METHODS: A single-centre retrospective observational cohort study was performed at Moorfields Eye Hospital (NHS Foundation Trust, London, U.K.) to identify patients who underwent cataract surgery whose procedure was intraoperatively described as being complicated by ZD between January 1, 2014, and August 22, 2019. Patient characteristics, intraoperative clinical findings, visual and refractive outcomes, and postoperative complications were recorded. RESULTS: ZD was identified intraoperatively in 447 eyes. In most cases (213 of 223; 96.8%), patients underwent a phacoemulsification procedure, not requiring any conversion to intracapsular or extracapsular extraction technique. Intraoperative complications increased to 46.2% (103 of 223), with no significant correlation with ZD width. Capsular tension rings (CTRs) were implanted in 43.4% of patients (97 of 223). The use of CTRs correlated with better postoperative visual and refractive outcomes. CONCLUSIONS: ZD is a serious complication of cataract surgery requiring prompt intraoperative diagnosis and proper management. While it tends to worsen cataract surgery outcomes, the implantation of CTRs during the surgical procedure seems to be associated with better postoperative visual and refractive results.


Subject(s)
Cataract Extraction , Cataract , Phacoemulsification , Humans , Retrospective Studies , Visual Acuity , Renal Dialysis/adverse effects , Cataract Extraction/adverse effects , Phacoemulsification/methods , Postoperative Complications/etiology , Cataract/complications , Referral and Consultation , United Kingdom
4.
J Cataract Refract Surg ; 50(1): 72-77, 2024 01 01.
Article in English | MEDLINE | ID: mdl-37732731

ABSTRACT

PURPOSE: To assess the extent of paper waste generated per year by instructions for use (IFUs) brochures included in intraocular lens (IOL) packaging in Europe and the U.S. SETTING: Rothschild Foundation Hospital, Paris, France; Royal Free London NHS Foundation Trust; Center for Sight, London, United Kingdom. DESIGN: Experimental study. METHODS: A sample of IOLs were collected and each IFU was weighed. In addition, the cumulative weight of these brochures used in cataract surgeries performed annually in Europe and the U.S. was estimated, and the potential annual paper conservation that could be achieved if all manufacturers adopted electronic IFUs (e-IFUs) in Europe and the U.S. was determined. RESULTS: The mean and standard deviation of the weight for overall IFUs, classic IFUs, and e-IFUs were 17.6 ± 13.8 g, 23.5 ± 13.2 g, and 2.9 ± 1.9 g, respectively. The estimated cumulative weight of paper generated from the IFUs accompanying implants used in European and U.S. cataract surgeries is 153 tons. If all manufacturers transition to e-IFUs, the cumulative weight saved would be 128 tons (-84%), equivalent to 120 tons of carbon dioxide equivalent and the preservation of more than 2000 trees annually. CONCLUSIONS: The classic IFUs in IOL packaging result in a significant amount of paper waste annually. Therefore, there is an urgent need for a rapid transition to e-IFU technology. The adoption of e-IFUs has already been authorized in Europe and the U.S., and it is crucial to expedite this process.


Subject(s)
Cataract Extraction , Cataract , Lenses, Intraocular , Humans , United States , Visual Acuity , Pamphlets , Europe
5.
Transl Vis Sci Technol ; 12(11): 11, 2023 11 01.
Article in English | MEDLINE | ID: mdl-37930666

ABSTRACT

Purpose: The primary objective of this research is to examine how precision in intraocular lens calculation formulas can be impacted by zeroing the mean error through adjustments in the effective lens position value. Additionally, the study aims to evaluate how this modification influences outcomes differently based on the source of the prediction error. Methods: In order to analyze the impact of individual variables on the standard deviation, the study maintained all variables constant except for one at a time. Subsequently, variations were introduced to specific parameters, such as corneal curvature radius, keratometric refractive index, axial length, and predicted implant position. Results: According to our findings, when zeroing the mean error is applied to correct for inaccuracies in corneal power estimation, it results in a significant and exponential rise in standard deviation, thus adversely affecting the formula's precision. However, when zeroing is employed to compensate for prediction errors stemming from axial length measurements or predicted implant position, the effect on precision is minimal or potentially beneficial. Conclusions: The study highlights the potential risks associated with the indiscriminate but necessary zeroing of prediction errors in implant power calculation formulas. The impact on formula precision greatly depends on the source of the error, underscoring the importance of error source when analyzing variations in the standard deviation of the prediction error after zeroing. Translational Relevance: Our study contributes to the ongoing effort to enhance the accuracy and reliability of these formulas, thereby improving the surgical outcomes for cataract patients.


Subject(s)
Cataract , Lenses, Intraocular , Humans , Reproducibility of Results , Cornea
6.
Front Med (Lausanne) ; 10: 1212314, 2023.
Article in English | MEDLINE | ID: mdl-37409272

ABSTRACT

Keratoconus is the most common corneal ectatic disorder. It is characterized by progressive corneal thinning with resultant irregular astigmatism and myopia. Its prevalence has been estimated at 1:375 to 1:2,000 people globally, with a considerably higher rate in the younger populations. Over the past two decades, there was a paradigm shift in the management of keratoconus. The treatment has expanded significantly from conservative management (e.g., spectacles and contact lenses wear) and penetrating keratoplasty to many other therapeutic and refractive modalities, including corneal cross-linking (with various protocols/techniques), combined CXL-keratorefractive surgeries, intracorneal ring segments, anterior lamellar keratoplasty, and more recently, Bowman's layer transplantation, stromal keratophakia, and stromal regeneration. Several recent large genome-wide association studies (GWAS) have identified important genetic mutations relevant to keratoconus, facilitating the development of potential gene therapy targeting keratoconus and halting the disease progression. In addition, attempts have been made to leverage the power of artificial intelligence-assisted algorithms in enabling earlier detection and progression prediction in keratoconus. In this review, we provide a comprehensive overview of the current and emerging treatment of keratoconus and propose a treatment algorithm for systematically guiding the management of this common clinical entity.

7.
Front Med (Lausanne) ; 10: 1152266, 2023.
Article in English | MEDLINE | ID: mdl-37293301

ABSTRACT

Purpose: To study the progression of keratoconus after cessation of eye rubbing with a minimum follow up of three-years. Design: Retrospective, monocentric, longitudinal cohort study of keratoconus patients with a minimum of 3 years follow-up. Participants: One hundred fifty three eyes of seventy-seven consecutive patients with keratoconus were included. Methods: Initial examination consisted of anterior and posterior segment evaluation using slit-lamp biomicroscopy. At the initial visit, patients were thoroughly informed of their pathology and instructed to stop rubbing their eyes. Eye rubbing cessation was assessed at all the follow-up visits at 6 months, 1 year, 2 years, 3 years, and yearly afterward. Corneal topography using the Pentacam® (Oculus®, Wetzlar, Germany) was used to obtain maximum and average anterior keratometry readings (Kmax and Kmean), as well as thinnest pachymetry (Pachymin, µm) in both eyes. Main outcome measures: The main outcomes measured were maximum keratometry (Kmax), mean keratometry (Kmean), and thinnest pachymetry (Pachymin) values at various time points to assess for keratoconus progression. Keratoconus progression was defined as a significant augmentation of Kmax (>1D), Kmean (>1D), or significant diminution of Pachymin (>5%) throughout the total follow-up duration. Results: One hundred fifty three eyes of seventy-seven patients (75.3% males) aged 26.4 years old, were followed for an average of 53 months. Over the course of the follow-up, there was no statistically significant variation of ∆Kmax (+0.04 ± 0.87; p = 0.34), ∆ Kmean (+0.30 ± 0.67; p = 0.27) nor ∆Pachymin (-4.36 ± 11.88; p = 0.64). Among the 26 of the 153 eyes which had at least one criterion of KC progression, 25 admitted continuing eye rubbing, or other at-risk behaviors. Conclusion: This study suggests that a significant proportion of keratoconus patients are likely to remain stable if close monitoring and strict ARB cessation are achieved, without the need for further intervention.

8.
J Clin Med ; 12(10)2023 May 11.
Article in English | MEDLINE | ID: mdl-37240510

ABSTRACT

To ascertain the theoretical impact of optical design variations of the intraocular lens (IOL) on the accuracy of IOL power formulas based on a single lens constant using a thick lens eye model. This impact was also simulated before and after optimization. We modeled 70 thick-lens pseudophakic eyes implanted with IOLs of symmetrical optical design and power comprised between 0.50 D and 35 D in 0.5-step increments. Modifications of the shape factor resulting in variations in the anterior and posterior radii of an IOL were made, keeping the central thickness and paraxial powers static. Geometry data from three IOL models were also used. Corresponding postoperative spherical equivalent (SE) were computed for different IOL powers and assimilated to a prediction error of the formula due to the sole change in optical design alone. Formula accuracy was studied before and after zeroization on a uniform and non-uniform realistic IOL power distribution. The impact of the incremental change in optic design variability depended on the IOL power. Design modifications theoretically induce an increase in the standard deviation (SD), Mean Absolute Error (MAE), and Root Mean Square (RMS) of the error. The values of these parameters reduce dramatically after zeroization. While the variations in optical design can affect refractive outcomes, especially in short eyes, the zeroization of the mean error theoretically reduces the impact of the IOL's design and power on the accuracy of IOL power calculation.

9.
IDCases ; 32: e01793, 2023.
Article in English | MEDLINE | ID: mdl-37207172

ABSTRACT

Infection by Candida spp is a potentially life-threatening condition among both immunocompromised and immunocompetent patients. Candida chorioretinitis can occur as a complication of candidemia and may develop into endophthalmitis if not detected and treated early, which can lead to irreversible visual loss. Here, we report on a 52-year-old diabetic woman who developed candidemia complicated by bilateral chorioretinitis following kidney transplantation. Antifungal therapy was immediately started but fundoscopic examination highlighted multiple bilateral chorioretinal lesions. Given new onset of vomiting and increased number of retinal lesions on repeat fundus examination a few weeks later, the patient underwent a positron emission tomography (PET) which revealed a mycotic arterial pseudoaneurysm at the renal graft anastomosis. It led ineluctably to transplantectomy, aneurysm flattening and vascular reconstruction a few days later. Blood cultures remained negative and fundus examination progressively showed a regression of chorioretinal lesions until their complete disappearance a few months later. Our case emphasizes the importance of a non-invasive examination which allowed to accelerate and optimize in a consequential way the management of the patient leading to her recovery after a long antifungal treatment.

10.
Am J Ophthalmol ; 253: 65-73, 2023 09.
Article in English | MEDLINE | ID: mdl-37150337

ABSTRACT

PURPOSE: To provide a simplified method to optimize lens constants to zero the mean prediction error (ME) of an intraocular lens (IOL) calculation formula, without the need to program the formula itself, by exploring the influence of IOL and corneal power on the refractive impact of variations in effective lens position. DESIGN: Theoretical development of an optimized formula and retrospective clinical evaluation on documented datasets. METHODS: Retrospective data from 8878 patients with cataracts with pre- and postoperative measurements available using 4 IOL models and 6 IOL power calculation formulas were examined. A schematic eye model was used to study the impact of small variations in effective lens position (ELP) on the postoperative spherical equivalent (SE) refraction. The impact of keratometry (K) and IOL power (P) on SE was investigated. A theoretical thick lens model was used to devise a formula to zero the average prediction error of an IOL power calculation formula. This was achieved by incrementing the predicted ELP, which could then be translated into an increment in the IOL constant. This method was tested on documented real-life postoperative datasets, using different IOL models and single-constant optimized IOL calculation formulas. RESULTS: For small variations in ELP, there was an exponential relationship between IOL power and the resultant postoperative refractive variation. The ELP adjustment necessary to zero the ME equated to a ratio between the ME and the mean of the following expression: 0.0006*(P2+2K*P) on the considered datasets. The accuracy of the values obtained using this formula was confirmed on documented postoperative datasets, and on published and nonpublished formulas. CONCLUSION: The proposed method allows surgeons without special expertise to optimize an IOL constant to nullify the ME on a documented dataset without coding the different formulas. The influence of individual eyes is proportional to the squared power of the implanted IOL.


Subject(s)
Lenses, Intraocular , Myopia , Phacoemulsification , Humans , Retrospective Studies , Myopia/surgery , Refraction, Ocular , Bias , Biometry , Optics and Photonics
11.
J Refract Surg ; 39(4): 266-272, 2023 Apr.
Article in English | MEDLINE | ID: mdl-37040212

ABSTRACT

PURPOSE: To predict the relationships between the keratometric index value that would match the total Gaussian corneal power and its related variables: anterior and posterior radii of curvature of the cornea, anterior-posterior corneal radius ratio (APR), and central corneal thickness. METHODS: The relationship between the APR and the keratometric index was approximated by calculating the analytical expression for the theoretical value of the keratometric index, which would make the keratometric power of the cornea equal to the total paraxial Gaussian power of the cornea. RESULTS: The study of the impact of variations in the radius of anterior and posterior curvature and central corneal thickness showed that the difference between exact and approximated best-matching theoretical keratometric index was less than 0.001 for all of the performed simulations. This translated to a variation in the total corneal power estimation of less than ±0.128 diopters. After refractive surgery, the estimated optimal keratometric index value is a function of the preoperative anterior keratometry, the preoperative APR, and the delivered correction. The larger the magnitude of myopic corrections, the greater the increase in postoperative APR value. CONCLUSIONS: It is possible to estimate the most compatible value of the keratometric index that allows simulated keratometric power to equal the total Gaussian corneal power. The obtained equations enable the evaluation of the impact of corneal variables such as the APR on the ideal keratometric index value. The use of 1.3375 for the keratometric index results in an overestimation of the total corneal power in most clinical situations. [J Refract Surg. 2023;39(4):266-272.].


Subject(s)
Myopia , Refractive Surgical Procedures , Humans , Corneal Topography/methods , Refraction, Ocular , Cornea , Myopia/surgery
12.
Cornea ; 42(8): 954-961, 2023 Aug 01.
Article in English | MEDLINE | ID: mdl-36155366

ABSTRACT

PURPOSE: The aim of this study was to determine the mechanisms leading to the refractive shift and intraocular lens calculation error induced by Descemet membrane endothelial keratoplasty (DMEK), using ocular biometry and corneal elevation tomography data. METHODS: This is a retrospective, monocentric cohort study. Eyes which underwent uncomplicated DMEK surgery with available pre-DMEK and post-DMEK Scheimpflug rotating camera data (Pentacam, Oculus, Wetzlar, Germany) were considered for inclusion with an age-matched control group of healthy corneas. Cataract surgery data were collected for triple-DMEK cases. DMEK-induced refractive shift (DIRS) and intraocular lens calculation error (DICE) were calculated. Pearson r correlation coefficient was calculated between each corneal parameter variation and both DIRS and DICE. RESULTS: DIRS was calculable for 49 eyes from 43 patients. It was 30.61% neutral, 53.06% hyperopic (36.73% > 1D), and 16.32% myopic (6.12% > 1 D). DICE was calculable for 30 eyes of 26 patients: It was 46.67% neutral, 40.00% hyperopic (10.00% > 1D), and 13.33% myopic (3.33% > 1D). DIRS and DICE were mainly associated with variations in PRC/ARC ratio, anterior average radii of curvature (ARC), posterior average radii of curvature (PRC), and posterior Q. CONCLUSIONS: Our results suggest that ARC variations, PRC/ARC ratio variations, PRC variations, and posterior Q variations are the most influential parameters for both DIRS and DICE. We suggest that a distinction between those different phenomenons, both currently described as "hyperopic shift" in the literature, should be made by researchers and clinicians.


Subject(s)
Descemet Stripping Endothelial Keratoplasty , Fuchs' Endothelial Dystrophy , Hyperopia , Lenses, Intraocular , Humans , Descemet Membrane/surgery , Visual Acuity , Cohort Studies , Retrospective Studies , Descemet Stripping Endothelial Keratoplasty/adverse effects , Descemet Stripping Endothelial Keratoplasty/methods , Lenses, Intraocular/adverse effects , Hyperopia/etiology , Hyperopia/surgery , Fuchs' Endothelial Dystrophy/surgery
13.
Transl Vis Sci Technol ; 11(9): 5, 2022 09 01.
Article in English | MEDLINE | ID: mdl-36069859

ABSTRACT

Purpose: To ascertain the theoretical impact of anatomical variations in the effective lens position (ELP) of the intraocular lens (IOL) in a thick lens eye model. The impact of optimization of IOL power formulas based on a single lens constant was also simulated. Methods: A schematic eye model was designed and manipulated to reflect changes in the ELP while keeping the optical design of the IOL unchanged. Corresponding relationships among variations in ELP, postoperative spherical equivalent refraction, and required IOL power adjustment to attain target refractions were computed for differing corneal powers (38 diopters [D], 43 D, and 48 D) with IOL power ranging from 1 to 35 D. Results: The change in ELP required to compensate for various systematic biases increased dramatically with low-power IOLs (less than 10 D) and was proportional to the magnitude of the change in refraction. The theoretical impact of the variation in ELP on postoperative refraction was nonlinear and highly dependent on the optical power of the IOL. The concomitant variations in IOL power and refraction at the spectacle plane, induced by varying the ELP, were linearly related. The influence of the corneal power was minimal. Conclusions: The consequences of variations in the lens constant mainly concern eyes receiving high-power IOLs. The compensation of a systematic bias by a constant increment of the ELP may induce a nonsystematic modification of the predicted IOL power, according to the biometric characteristics of the eyes studied. Translational Relevance: Optimizing IOL power formulas by altering the ELP may induce nonsystematic modification of the predicted IOL power.


Subject(s)
Lens, Crystalline , Lenses, Intraocular , Biometry , Cornea/surgery , Refraction, Ocular
14.
Asia Pac J Ophthalmol (Phila) ; 10(3): 268-281, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-34224467

ABSTRACT

ABSTRACT: Corneal diseases, uncorrected refractive errors, and cataract represent the major causes of blindness globally. The number of refractive surgeries, either cornea- or lens-based, is also on the rise as the demand for perfect vision continues to increase. With the recent advancement and potential promises of artificial intelligence (AI) technologies demonstrated in the realm of ophthalmology, particularly retinal diseases and glaucoma, AI researchers and clinicians are now channeling their focus toward the less explored ophthalmic areas related to the anterior segment of the eye. Conditions that rely on anterior segment imaging modalities, including slit-lamp photography, anterior segment optical coherence tomography, corneal tomography, in vivo confocal microscopy and/or optical biometers, are the most commonly explored areas. These include infectious keratitis, keratoconus, corneal grafts, ocular surface pathologies, preoperative screening before refractive surgery, intraocular lens calculation, and automated refraction, among others. In this review, we aimed to provide a comprehensive update on the utilization of AI in anterior segment diseases, with particular emphasis on the recent advancement in the past few years. In addition, we demystify some of the basic principles and terminologies related to AI, particularly machine learning and deep learning, to help improve the understanding, research and clinical implementation of these AI technologies among the ophthalmologists and vision scientists. As we march toward the era of digital health, guidelines such as CONSORT-AI, SPIRIT-AI, and STARD-AI will play crucial roles in guiding and standardizing the conduct and reporting of AI-related trials, ultimately promoting their potential for clinical translation.


Subject(s)
Cataract , Ophthalmology , Refractive Surgical Procedures , Artificial Intelligence , Cornea/surgery , Humans , Keratoconus
16.
Am J Ophthalmol ; 232: 58-69, 2021 12.
Article in English | MEDLINE | ID: mdl-33992611

ABSTRACT

PURPOSE: To describe an open-source, reproducible, step-by-step method to design sum-of-segments thick intraocular lens (IOL) calculation formulas, and to evaluate a formula built using this methodology. DESIGN: Retrospective, multicenter case series METHODS: A set of 4242 eyes implanted with Finevision IOLs (PhysIOL, Liège, Belgium) was used to devise the formula design process and build the formula. A different set of 677 eyes from the same center was kept separate to serve as a test set. The resulting formula was evaluated on the test set as well as another independent data set of 262 eyes. RESULTS: The lowest standard deviation (SD) of prediction errors on Set 1 were obtained with the PEARL-DGS formula (±0.382 D), followed by K6 and Olsen (±0.394 D), EVO 2.0 (±0.398 D), RBF 3.0, and BUII (±0.402 D). The formula yielding the lowest SD on Set 2 was the PEARL-DGS (±0.269 D), followed by Olsen (±0.272 D), K6 (±0.276 D), EVO 2.0 (±0.277 D), and BUII (±0.301 D). CONCLUSION: Our methodology achieved an accuracy comparable to other state-of-the-art IOL formulas. The open-source tools provided in this article could allow other researchers to reproduce our results using their own data sets, with other IOL models, population settings, biometric devices, and measured, rather than calculated, posterior corneal radius of curvature or sum-of-segments axial lengths.


Subject(s)
Lenses, Intraocular , Phacoemulsification , Axial Length, Eye , Biometry , Humans , Machine Learning , Optics and Photonics , Refraction, Ocular , Retrospective Studies
17.
Transl Vis Sci Technol ; 10(4): 27, 2021 04 01.
Article in English | MEDLINE | ID: mdl-34004006

ABSTRACT

Purpose: To describe a formula to back-calculate the theoretical position of the principal object plane of an intraocular lens (IOL), as well as the theoretical anatomic position in a thick lens eye model. A study was conducted to ascertain the impact of variations in design and IOL power, on the refractive outcomes of cataract surgery. Methods: A schematic eye model was designed and manipulated to reflect changes in the anterior and posterior radii of an IOL, while keeping the central thickness and paraxial powers static. Modifications of the shape factor (X) of the IOL affects the thick lens estimated effective lens position (ELP). Corresponding postoperative spherical equivalent (SE) were computed for different IOL powers (-5 diopters [D], 5 D, 15 D, 25 D, and 35 D) with X ranging from -1 to +1 by 0.1. Results: The impact of the thick lens estimated effective lens position shift on postoperative refraction was highly dependent on the optical power of the IOL and its thickness. Design modifications could theoretically induce postoperative refraction variations between approximately 0.50 and 3.0 D, for implant powers ranging from 15 D to 35 D. Conclusions: This work could be of interest for researchers involved in the design of IOL power calculation formulas. The importance of IOL geometry in refractive outcomes, especially for short eyes, should challenge the fact that these data are not usually published by IOL manufacturers. Translational Relevance: The back-calculation of the estimated effective lens position is central to intraocular lens calculation formulas, especially for artificial intelligence-based optical formulas, where the algorithm can be trained to predict this value.


Subject(s)
Cataract Extraction , Lenses, Intraocular , Artificial Intelligence , Machine Learning , Refraction, Ocular
18.
BMJ Case Rep ; 14(3)2021 Mar 02.
Article in English | MEDLINE | ID: mdl-33653853

ABSTRACT

A 25-year-old longsighted woman presented with a history of spectacle and contact lens induced exacerbation of Tourette syndrome symptoms. Preoperatively, she had very poor unaided vision (6/60), achieving good (6/9) vision in both eyes with spectacle correction. The patient underwent bilateral simultaneous implantation of phakic implantable collamer lens (ICL) implants (STAAR, USA) which sit in front of the natural lens. Postoperatively, her uncorrected visual acuity was markedly improved as were her manifestations of Tourette syndrome. She achieved her full potential of unaided vision (6/9). This is the first documented case of Tourette syndrome triggered by glasses and contact lenses in which bilateral phakic toric lens implants were effective in improving vision and controlling motor symptoms. Phakic toric ICL implantation is a reversible technique for the correction of visually significant ametropia in selected patients and has improved this patient's quality of life.


Subject(s)
Contact Lenses , Lenses, Intraocular , Myopia , Phakic Intraocular Lenses , Tourette Syndrome , Adult , Eyeglasses , Female , Follow-Up Studies , Humans , Lens Implantation, Intraocular/adverse effects , Myopia/surgery , Quality of Life , Refraction, Ocular
19.
BMJ Case Rep ; 14(3)2021 Mar 17.
Article in English | MEDLINE | ID: mdl-33731403

ABSTRACT

An adult man was struck in the face by his own aerial drone. The propellers hit the upper face region leading to forehead and eyelid lacerations, a partial scleral laceration, conjunctival laceration, hyphaema, traumatic iritis and forward displacement of one haptic of the intraocular lens from a previous cataract surgery. In the last decade, drone use has significantly increased and drone-related injuries have become an emerging cause of trauma. Our case raises awareness of the risks and highlights the need for improvement in regulation of drone use.


Subject(s)
Drug-Related Side Effects and Adverse Reactions , Eye Injuries , Lacerations , Lens, Crystalline , Adult , Eye Injuries/etiology , Face , Humans , Lacerations/etiology , Male
20.
J Refract Surg ; 37(1): 16-24, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33432991

ABSTRACT

PURPOSE: To evaluate the visual outcomes of patients with presbyopic hyperopia, comparing the current standard of monovision treatment with a novel bilateral presbyopic LASIK (Custom-Q mode) technique. METHODS: This prospective comparative study of consecutive eligible patients with presbyopic hyperopia undergoing a bilateral presbyopic laser in situ keratomileusis technique was conducted between January 2018 and February 2019. After contact lens-simulated monovision measurements were obtained, the non-dominant eyes had a negative aspheric ablation profile planned using the Custom-Q nomogram (Alcon Laboratories, Inc). The dominant eye was operated on with a positive aspheric ablation profile. Visual acuity testing, refraction, corneal asphericity (▵Q), higher order aberrations, and a satisfaction questionnaire (National Eye Institute Refractive Error Quality of Life) were evaluated after the monovision trial and postoperatively. RESULTS: Twenty-eight patients, with a mean age of 56.03 ± 4.31 years, were included in the study. At 6 months, 100% of patients achieved 20/20 or better binocular uncorrected distance visual acuity (UDVA) versus 57% in the monovision group, 100% of patients achieved 20/25 or better binocular uncorrected intermediate visual acuity versus 32% in the monovision group, and 92.86% of patients achieved 20/25 or better binocular uncorrected near visual acuity (UNVA) in both groups. In contact lens monovision simulation, no patient reached a UDVA of 20/50 or better, with only 3.6% having a UNVA of 20/40 or better. The questionnaire demonstrated high patient satisfaction. CONCLUSIONS: The outcomes confirm the superiority of increased depth of focus using negative spherical aberration modulation in the non-dominant eye compared with contact lens monovision. They also demonstrate the effectiveness of positive spherical aberration induction to improve intermediate and near vision in the dominant eye. [J Refract Surg. 2021;37(1):16-24.].


Subject(s)
Hyperopia , Keratomileusis, Laser In Situ , Presbyopia , Humans , Hyperopia/surgery , Lasers, Excimer/therapeutic use , Middle Aged , Presbyopia/surgery , Prospective Studies , Quality of Life , Refraction, Ocular , Treatment Outcome , Vision, Binocular
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