"Predicting intraocular lens tilt using a machine learning concept".

OBJECTIVE: Aim of this study was to use a combination of partial least squares regression and a machine learning approach to predict IOL tilt using pre-operative biometry data. SETTING: Patients scheduled for cataract surgery at the Kepler University Clinic Linz. DESIGN: Prospective single center study. METHODS: Optical coherence tomography, autorefraction and subjective refraction was performed at baseline and 8 weeks after cataract surgery. In analysis I only one eye per patient was included and a tilt prediction model was generated. In analysis II a pair-wise comparison between right and left eyes was performed. RESULTS: In analysis I 50 eyes of 50 patients were analysed. Difference in amount, orientation and vector from pre- to post-operative lens tilt was -0.13°, 2.14° and 1.20° respectively. A high predictive power (variable importance for projection) for post-operative tilt prediction was found for pre-operative tilt (VIP=2.2), pupil decentration (VIP=1.5), lens thickness (VIP=1.1), axial eye length (VIP=0.9) and pre-operative lens decentration (VIP=0.8). These variables were applied to a machine learning algorithm resulting in an out of bag score of 0.92°. In analysis II 76 eyes of 38 patients were included. The difference of pre- to post-operative IOL tilt of right and left eyes of the same individuum was statistically relevant. CONCLUSION: Post-operative IOL tilt showed excellent predictability using pre-operative biometry data and a combination of partial least squares regression and a machine learning algorithm. Pre-operative lens tilt, pupil decentration, lens thickness, axial eye length and pre-operative lens decentration were found to be the most relevant parameters for this prediction model.

Rotational stability and capsular bag performance of a hydrophobic acrylic open-loop single-piece intraocular lens.

PURPOSE: To evaluate the rotational stability and capsular bag performance of a blue light-absorbing hydrophobic acrylic open-loop single-piece intraocular lens (IOL) with a blast-finished anchor wing haptic design during the first 6 postoperative months. METHODS: In this prospective clinical study, patients with age-related cataract and potential postoperative corrected distance visual acuity (CDVA) of 0.2 logMAR or better were included. The patients received a non-toric hydrophobic acrylic single-piece IOL with an axis mark (YST0.00; Nidek Co. Ltd, Japan). Surgeries were video-taped. Retroillumination images were acquired 1 h, 1 week and 6 months postoperatively. Rotational stability was assessed by precise image overlay. At 6 months, Purkinje meter measurements were performed to evaluate tilt and decentration. RESULTS: In total, 100 eyes of 77 patients were included in the analysis. Mean absolute rotation was 2.1 ± 1.7° (median 1.7, range: 0-7.9) at 6 months (1 h - 6 months postoperatively). IOL rotation was ≤3° and ≤6° in 74 (74%) and 98 (98%) eyes, respectively. Mean absolute IOL rotation from the end of surgery to 6 months was 2.5 ± 2.2° (median 2.3, range: 0-15.6; n = 78). Mean tilt (pupillary axis) and decentration were 4.1 ± 1.9° (median 4.0, range: 0.5-8.2) and 0.35 ± 0.17 mm (median 0.32, range: 0.06-0.91) respectively (n = 84). Postoperatively, 98 (98%) eyes achieved a CDVA of 0.2 logMAR or better, 95 (95%) of ≤0.1 and 81 (81%) of ≤0.0. CONCLUSIONS: This hydrophobic acrylic single-piece IOL showed an excellent rotational stability and capsular bag position with low tilt and decentration values.

Repeatability of biometry in patients with meibomian gland dysfunction before and after vectored thermal pulsation therapy: A randomized, controlled trial.

PURPOSE: To evaluate the effect of vectored thermal pulsation therapy (VTPT) on the repeatability of biometry readings of two different optical biometers in patients with meibomian gland dysfunction (MGD). METHODS: Patients affected by MGD were included in this prospective, randomized, controlled, investigator-masked study. One eye was randomized to VTPT (LipiFlow®, Johnson & Johnson), and the contralateral eye served as a control. Three visits were scheduled at baseline, 2 weeks and 3 months after the treatment. The main outcome parameter of the study was the repeatability of three calculations of emmetropic intraocular lens power (EIOLP) at the 3 months visit as compared to baseline using an optical biometer (IOLMaster® 700, Carl Zeiss Meditec AG). Repeatability of different keratometry values obtained by the optical biometer and a Placido-disc topographer (MS-39®, CSO) served as secondary outcome parameters. RESULTS: Twenty-nine patients were included in the final analysis. While tear film parameters improved in the study eyes, there were no significant differences regarding the repeatability of three EIOLP measurements between baseline and 3-months-visit in both eyes (p > 0.05) and keratometry measurements in both the optical biometer and the Placido-disc topographer. Remarkably, throughout all study visits, there were some outliers regarding the repeatability of measurements. CONCLUSION: While both devices showed high repeatability regarding EIOLP and keratometry, future studies are needed to detect high-risk patients for poor repeatability.

Diagnostic Potential of Anterior Segment Optical Coherence Tomography Scans for Pseudomonas Keratitis.

Purpose: The purpose of this study was to investigate the diagnostic value of anterior segment optical coherence tomography (AS-OCT) scans for Pseudomonas keratitis. Methods: Patients with treatment-naïve keratitis underwent AS-OCT imaging. The following parameters were evaluated: corneal thickness (CT), infiltrate thickness (IT), infiltrate diameter (ID), tissue loss/gain, entropy, and distance of the lesion from the corneal pupillary center. Three different OCT devices were used for the analysis. The relationship between the detected pathogen and the OCT patterns was analyzed. Results: Nineteen eyes of 19 patients were included in the analysis: seven cases in the Pseudomonas group and 12 cases in the Gram-positive group. The mean (SD) values for the Pseudomonas and Gram-positive groups, respectively, were as follows: CT, 834 µm (165 µm) and 760 µm (120 µm); IT, 290 µm (152 µm) and 287 µm (84 µm); ID, 2067 µm (1470 µm) and 1307 µm (745 µm); distance to center, 3.0 mm (1.2 mm) and 3.0 mm (1.6 mm); epithelial defect, 1193 µm (586 µm) and 484 µm (615 µm); tissue gain, +31% (19%) and +10% (12%); and entropy level, 4.0 (0.8) and 3.9 (1.1). Conclusions: This study introduces novel insights by identifying specific OCT parameters that distinguish Pseudomonas keratitis, including a 30% tissue gain. These findings align with earlier research that underscores the potential of OCT in differentiating various pathogens causing keratitis. Translational Relevance: The findings of this study could be used to develop new diagnostic strategies for Pseudomonas keratitis. The OCT findings could be used to develop new biomarkers for the infection.

Assessing the astigmatism-reducing effect of toric intraocular lenses in eyes with low astigmatism: randomized masked bilateral comparison.

PURPOSE: To evaluate the astigmatism-reducing effect of toric intraocular lenses (IOLs) for low amounts of corneal astigmatism. SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Randomized, masked, controlled trial with bilateral comparison. METHODS: Patients scheduled for bilateral cataract surgery and a corneal astigmatism in both eyes between 0.75 diopters (D) and 1.5 D were included in this study. The first eye was randomized to receive either a toric IOL or a nontoric IOL, and the contralateral eye received the other type of IOL. At the follow-up visits, optical biometry, corneal measurements with tomography and topography, autorefraction, subjective refraction, corrected and uncorrected distance visual acuity (CDVA/UDVA) with ETDRS charts and a questionnaire were performed. RESULTS: 58 eyes were included in the study. Postoperative median UDVA was 0.00 (logMAR) in the toric eyes and 0.10 in the nontoric eyes ( P = .03). The median CDVA was 0.00 in both groups ( P = .60). Median residual astigmatism determined by subjective refraction and autorefraction in the toric eyes was 0.25 D and 0.50 D, respectively ( P = .04), and 0.50 D and 1.00 D in the nontoric eyes, respectively ( P < .001). CONCLUSIONS: The use of a toric IOL appears to be appropriate from a threshold value of approximately 0.75 D preoperative corneal astigmatism. Further studies in a larger patient population are needed to confirm these results.

Capsular tension ring as protective measure against in-the-bag dislocations after cataract surgery.

PURPOSE: To assess the influence of capsular tension ring (CTR) implantation on the development of in-the-bag (ITB) dislocations after cataract surgery. SETTING: Department of Ophthalmology Graz, Graz, Austria. DESIGN: Single-center, retrospective cohort study. METHODS: The medical records of patients who underwent cataract operation between 1996 and 2017 were analyzed. Cox proportional hazards regression analysis was used to assess the influence of CTR implantation and other predisposing factors (pseudoexfoliation [PEX], age, retinitis pigmentosa, sex, zonular weakness, uveitis, high myopia, and intraocular lens design and material) on ITB dislocations. RESULTS: ITB dislocations were found in 111 (0.16%) of 68199 eyes (46 632 patients). In the multivariate analysis adjusted for other predisposing risk factors, a CTR implantation was associated with a lower risk of an ITB dislocation (hazard ratio [HR], 0.29; 95% CI, 0.11-0.80; P = .017). In eyes with PEX, a CTR implantation was associated with an HR of 0.16 (95% CI, 0.04-0.70; P = .015), whereas eyes without PEX had an HR of 0.80 (95% CI, 0.14-4.41; P = .793). A CTR implantation in eyes with zonular weakness resulted in a potentially lower risk (HR, 0.37; 95% CI, 0.12-1.12; P = .078). CONCLUSIONS: According to the dataset, implantation of a CTR was a protective measure against an ITB dislocation. Especially in patients with zonular weakness and PEX, the CTR implantation was association with a lower risk of ITB dislocations. In patients without PEX, no association was established.

Evaluation of phakic intraocular lens power calculation using the new Linz-Homburg-Castrop formula and comparison with four conventional methods.

PURPOSE: To evaluate the accuracy of phakic intraocular lens (pIOL) power calculation in a middle European patient cohort. SETTING: EyeLaser Clinic, Linz, Austria. DESIGN: Single-center single-surgeon retrospective consecutive case series. METHODS: Patients were included after uneventful pIOL surgery implanting 91 nontoric and toric Visian implantable collamer lens model V4c. Online Calculation and Ordering System (OCOS) software, JPhakic software, Olsen-Feingold formula, Holladay formula, and Linz-Homburg-Castrop (LHC) formula were compared. When possible, lens constants were optimized for the patient cohort. Data of single eye per patient were included. Outcome measures were mean absolute prediction error, median absolute prediction error, mean prediction error with SD, and median prediction error, as well as the percentage of eyes with an absolute prediction error within limits of 0.25 diopters (D), 0.5 D, 0.75 D, and 1.0 D. RESULTS: 91 eyes of 91 patients were assessed. After application of the Cochran Q test, the Olsen-Feingold formula achieved a significantly lower percentage of eyes within an absolute prediction error of 1.0 D than all other methods. CONCLUSIONS: In the patient cohort, OCOS software, JPhakic software, and Holladay and LHC formulas showed equal results and can be cross-checked. The LHC formula was not published before. A ready-to-use Excel sheet is available as an addendum.

The 10,000 Eyes Study: Analysis of Keratometry, Abulafia-Koch regression transformation, and Biometric Eye Parameters Obtained With Swept-Source Optical Coherence Tomography.

PURPOSE: To analyze Abulafia-Koch regression (AKRT), anterior and posterior astigmatism (K and TK), and evaluate biometry data in a large population. DESIGN: Retrospective cross-sectional study. METHODS: This multicenter (2 tertiary care centers) study analyzed datasets acquired between 2017 and 2020. Axial length (AL), corneal front and back radii (including meridians for K and TK conversion), horizontal corneal diameter, anterior chamber depth, lens thickness, and central corneal thickness were measured using telecentric keratometry and swept-source optical coherence tomography-based biometry (IOLMaster 700; Carl Zeiss Meditec AG). Cooke-modified axial length (CMAL) and AKRT were calculated. Difference vectors between K and TK astigmatism and between AKRT and TK astigmatism were compared. RESULTS: A total of 10,300 eyes from 6388 patients were assessed. Difference vectors for K and TK were significantly smaller than for AKRT and TK. K measurement showed a configuration of 51.49% of with-the-rule astigmatism and 30.51% against-the-rule astigmatism, TK measurement showed a configuration of 41.60% of with-the-rule astigmatism and 40.21% against-the-rule astigmatism. Mean total astigmatism was -0.94 ± 0.74 dpt. Mean values for AL and CMAL were 23.70 ± 1.39 mm and 23.70 ± 1.34 mm, respectively. Anterior chamber depth, lens thickness, horizontal corneal diameter, AL, and age were all correlated with each other. CONCLUSION: Astigmatism analysis showed less difference between K and TK than between AKRT and TK. There were significantly fewer eyes with with-the-rule astigmatism and more eyes with against-the-rule astigmatism configuration in TK-derived than in K-derived keratometry. The study provides data on gender and generational differences in biometry. Significant intersexual differences in AL and CMAL were observed, with CMAL providing lower standard deviation compared with AL.

An evaluation of the efficacy of a supplemental computer-based tutorial to enhance the informed consent process for cataract surgery: an exploratory randomized clinical study.

BACKGROUND: To assess whether informing patients with a computer-based tutorial in addition to standard informed consent influences the patient's attitude towards surgery and increases patient's knowledge. METHODS: In this prospective, exploratory, randomized clinical study, patients scheduled for their first eye cataract surgery were randomly allocated to two groups, receiving standard face-to-face informed consent (control group) or additionally using an interactive computer-based tool (CatInfo) containing an audiovisual presentation about cataract and its treatment (study group). Cataract-related knowledge and decisional confidence (decisional conflict scale (DCS)) were assessed as well as one-month postoperatively decisional regret (decision regret scale (DRS)) and willingness to exchange face-to-face discussion time for the use of such a tool. RESULTS: The study comprised 134 patients, 64 patients in the study group and 70 in the control group. Patients in the study group answered more questions correctly, 16.3 ± 2.0 (median 16.5, 11.0-19.0) versus 15.5 ± 1.9 (median 16.0, 8.0-19.0; p = 0.01). Patients showed a high decisional confidence with a study group mean DCS score of 92.4 ± 9.8 (median 96.9, 65.6-100) and control group score of 91.6 ± 10.9 (median 95.3, 43.3-100; p = 0.52). Mean DRS score in the study group was 2.5 ± 8.0 (median 0, 0-40) and 4.3 ± 12.5 (median 0, 0-75) in the control group (p = 0.14). Of study group patients 23 (67.6%) were willing to trade time, on average 158 ± 180 s (median 120 s, 45-900). Satisfaction with the tool was high with a mean of 9.1 ± 1.3 out of 10 (median 9.7, 5.0-10). CONCLUSIONS: Cataract-related knowledge was generally good, with slightly higher scores in the study group. In both groups, decisional confidence was high and regret after surgery was low. A tendency towards slightly higher decisional confidence and lower regret was found in the study group, although these differences were not statistically significant. Additional use of an interactive computer-based tool may prove useful in the informed consent process in a high-volume cataract outpatient setting. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04975126. Retrospectively registered - July 23, 2021.

Influence of combined phacovitrectomy without tamponade on intraocular lens displacement and postoperative refraction.

PURPOSE: To compare phacoemulsification versus phacovitrectomy regarding postoperative intraocular lens (IOL) shift and refraction. METHODS: This prospective bilateral comparison study included 40 eyes of 20 patients. Inclusion criteria were combined phacovitrectomy without gas/air tamponade in one eye and cataract surgery in the contralateral eye with implantation of the same IOL. Postoperative anterior chamber depth (ACD) was compared between both groups 1-5 hr, 1 day and 8 weeks after surgery. Postoperative refraction was compared after 8 weeks using the Holladay I, HofferQ, SRK/T, Haigis and Barrett formulae. RESULTS: There were no intergroup differences in ACD (8 weeks: 0.02 mm absolute difference, SD 0.22, range -0.36 to 0.65, p = 0.401), mean absolute refractive error (8 weeks: Holladay I p = 0.452; HofferQ p = 0.475; SRK/T p = 0.498; Haigis p = 0.869; and Barrett p = 0.352) or percentages within the 0.5 D and 1.0 D range at any time-point. All formulae were optimized for the phacovitrectomy and the cataract groups. There was no correlation of macular thickness change and refractive error (cataract group r2 = -0.13, p = 0.58; phacovitrectomy group r2 = -0.10, p = 0.68). CONCLUSION: Combined phacovitrectomy without air/ gas tamponade caused neither ACD displacement nor refractive shifts compared to phacoemulsification alone. Surgically induced macular thickness change had no significant influence on postoperative refraction in this study. All five IOL formulae showed comparable postoperative refractive outcomes.

Project Hyperopic Power Prediction II: The Effects of Second Eye Refinement Methods on Prediction Error in Hyperopic Eyes.

PURPOSE: The purpose of the study was to evaluate the potential accuracy of different second eye refinement methods in a patient cohort with short axial eye length to assess the performance of intraocular lens (IOL) power calculation schemes in high hyperopes. METHODS: The study design was a single-center, single-surgeon retrospective consecutive case series. The setting of the study was in Augen- und Laserklinik, Castrop-Rauxel, Germany. Patients were assessed after uneventful bilateral cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were an axial eye length of ≤21.5 mm and/or emmetropizing IOL power of >28.5 dpt. Outcome measures were the mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with standard deviation, median prediction error, and the percentage of eyes with an absolute prediction error (absPE) within 0.25 dpt, 0.5 dpt, 0.75 dpt, or 1.0 dpt. Second eye refinement was performed using the first eye prediction error, either with a correction coefficient of 0.50 (SER1), or an individual coefficient optimized for MAE. RESULTS: A total of 55 patients were assessed. A statistically significant reduction in the absPE after the application of SER1 was observed in 9 of 13 formulae. The SER1 refined Hoffer Q, refined Holladay I, refined Holladay II, refined Kane, refined Okulix, and refined PEARL-DGS provided a smaller absPE than other methods. CONCLUSION: In this patient cohort with a short axial eye length, the second eye refinement led to a lower MAE in almost all formulae. The use of refinement in Kane, Okulix, PEARL-DGS, and Castrop formulae exhibited the lowest MAE.

Structure-Function Analysis of MP-3 Microperimetry versus Octopus Perimetry in Central Glaucomatous Visual Field Defects.

INTRODUCTION: The aim of this study was to compare the structure-function relationship with microperimetry and Octopus perimetry in primary open-angle glaucoma (POAG) patients with central visual field (VF) defects. METHODS: Forty eyes of 24 patients with POAG were enrolled. Circumpapillary retinal nerve fiber layer (cpRNFL) analysis measured by spectral-domain optical coherence tomography (SD-OCT) of the superotemporal, temporal, and inferotemporal optic-nerve head sectors were related to corresponding microperimetric and Octopus VF clusters using the G2 grid-pattern with dynamic strategy, respectively. The structure-function relationships of both devices were assessed via a segmented regression, as well as linear regression across overall SD-OCT cpRNFL values and outside normative (<1%) SD-OCT cpRNFL values. RESULTS: Linear and segmented regression fits were similar with both devices. Across overall cpRNFL sectorial values, structure-function relations for the superotemporal, temporal, and inferotemporal sectors were R2 = 0.176 (p = <0.001), R2 = 0.008 (p = 0.069), and R2 = 0.294 (p = <0.001) for microperimetry and R2 = 0.189 (p = <0.001), R2 = 0.020 (p = 0.002), and R2 = 0.326 (p = <0.001) for Octopus perimetry. For corresponding values outside normative limits (<1%), the relationships were R2 = 0.113 (p = <0.001), R2 = 0.001 (p = 0.836), and R2 = 0.420 (p = <0.001) for microperimetry and R2 = 0.192 (p = <0.001), R2 = 0.002, (p = 0.336), and R2 = 0.366 (p = <0.001) for Octopus perimetry. DISCUSSION/CONCLUSION: Structure-function analysis was similar for both devices. Fundus-tracking should be further evaluated in a longitudinal setting in patients affected by glaucoma.

Influence of Biometric Data on Planning Strabismus Surgery. / Einfluss von biometrischen Daten auf die Planung der Augenmuskeloperation.

PURPOSE: To evaluate the influence of optical biometry data (axial eye length, anterior chamber depth) on planning strabismus surgery using a simulation software and partial least squares regression. METHODS: This retrospective study included patients who had undergone strabismus surgery in one eye involving only the horizontal eye muscles. Furthermore, optical biometry had been performed and the extent of strabismus had been measured pre- and postoperatively. In the next step the strabismus surgery was simulated (See++, RISC, Austria) with and without axial eye length data. In the last step, anatomical data of the eye were used and their influence on the postoperative extent of strabismus was evaluated using partial least squares regression and boot strapping. RESULTS: Of 97 patients, 92 were included in the analysis. In all cases the extent of strabismus was reduced by at least 25% and in 60% of the cases the reduction was at least 75%. Taking the axial eye length into account improved the simulation slightly (change of surgical planning: 0.30 mm, standard deviation 1.65 mm). DISCUSSION: The simulation model used showed that including the axial eye length is useful for strabismus surgery planning. However, the anterior chamber depth/axial eye length was found to have a significantly greater impact.

Project hyperopic power prediction: accuracy of 13 different concepts for intraocular lens calculation in short eyes.

PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power calculation in a patient cohort with short axial eye length to assess the performance of IOL power calculation schemes in strong hyperopes. METHODOLOGY: The study was a single centre, single surgeon retrospective consecutive case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Inclusion of patients after uneventful cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were axial eye length <21.5 mm and/or emmetropising IOL power >28.5 D. Lens constants were optimised on a separate patient cohort considering the full bandwidth of axial eye length. Data of one single eye per patient were randomly included. The outcome measures were: mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with SD and median prediction error and the percentage of eyes with an MAE within 0.25 D, 0.5 D, 0.75 D and 1.0 D. RESULTS: A total of 150 eyes from 150 patients were assessed. Okulix, PEARL-DGS, Kane and Castrop provided a statistically significantly smaller MAE compared with the Hoffer Q and SRK/T formulae. CONCLUSION: In our patient cohort with short axial eye length, the use of PEARL-DGS, Okulix, Kane or Castrop formulae showed the lowest MAE. The Castrop formula has not been published before, but will be disclosed with a ready-to-use Excel sheet as an addendum to this paper.

Lasting Effects: Seven Year Results of the Castrop Nomogram for Femtosecond Laser-Assisted Paired Corneal Arcuate Incisions.

PURPOSE: Long-term results of arcuate incisions are rarely reported. This is unfortunate as long-term stability of astigmatic correction is of great interest to surgeons performing astigmatic correction. This study investigates the 7 year stability of results after application of femtosecond laser-assisted arcuate incisions with the Castrop nomogram. METHODS: Prospective interventional case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Single site, single surgeon study. Seven year results of cataract patients with low to moderate corneal astigmatism receiving femtosecond laser-assisted arcuate incisions using a TechnolasVictus SW 2.7 (Bausch & Lomb Inc, Dornach, Germany) were assessed and compared to 1 year results. Outcome evaluation was based on astigmatic vector analysis, manifest refraction, and visual acuity. RESULTS: The study analyzed 19 eyes of 19 patients 7 years after surgery. Ocular residual astigmatism changed from -0.26 to -0.39 D. Preoperative corneal astigmatism was -1.51 D. Correction Index changed from 1.0 to 1.16. The magnitude of difference vector changed from 0.26 to 0.39 D. The index of success changed from 0.20 to 0.29. Spherical equivalent remained stable. A slight tendency to change toward astigmatic overcorrection was mainly observed for patients with preoperative with the rule astigmatism, but not with patients with against the rule astigmatism. CONCLUSIONS: The Castrop nomogram showed stable results 7 years after surgery. Similar to toric IOL surgery, it is advisable to be less aggressive when correcting with the rule astigmatism, to avoid overcorrection over a long period.

Evaluation of intraoperative aphakic eye axial length measurements using swept-source OCT.

PURPOSE: To evaluate intraoperative aphakic eye axial length (AL) measurements using swept-source optical coherence tomography (SS-OCT). SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Prospective single-center study. METHODS: Patients scheduled for cataract surgery were measured using SS-OCT (IOLMaster 700, Carl Zeiss Meditec AG) to assess the AL. Intraoperatively (intra-OP), SS-OCT measurements were performed with a prototype device (IOLMaster 700 connected to an OPMI Lumera 700 microscope, CZM) at the beginning of cataract surgery furthermore of the aphakic eye and 2 months after surgery. RESULTS: 106 patients were included. Of the 59 eyes of 59 patients, the phakic median AL preoperatively and intra-OP was 23.61 mm ± 0.96 (standard deviation [SD]) and 23.51 mm ± 0.96 (SD), respectively. The absolute median difference was 0.028 ± 0.02 (SD) (P = .049). Median phakic AL intra-OP vs 2 months postoperatively (post-OP) was 23.51 mm ± 0.97 (SD) vs 23.49 mm ± 0.95 (SD). The absolute median difference was 0.049 ± 0.04 (SD) (P = .000). Median AL intra-OP aphakic vs 2 months post-OP pseudophakic was 23.42 mm ± 0.97 (SD) vs 23.42 mm ± 0.97 (SD), respectively. Absolute median difference was 0.038 ± 0.04 (SD) (P = .379). CONCLUSIONS: Intra-OP, SS-OCT technology of the phakic and aphakic eye shows excellent comparability to preoperative and postoperative measurements. This technique allows AL measurements with high precision in cases in which preoperative biometric measurements are not possible.

Physics-aware learning and domain-specific loss design in ophthalmology.

The human cataract, a developing opacification of the human eye lens, currently constitutes the world's most frequent cause for blindness. As a result, cataract surgery has become the most frequently performed ophthalmic surgery in the world. By removing the human lens and replacing it with an artificial intraocular lens (IOL), the optical system of the eye is restored. In order to receive a good refractive result, the IOL specifications, especially the refractive power, have to be determined precisely prior to surgery. In the last years, there has been a body of work to perform this prediction by using biometric information extracted from OCT imaging data, recently also by machine learning (ML) methods. Approaches so far consider only biometric information or physical modelling, but provide no effective combination, while often also neglecting IOL geometry. Additionally, ML on small data sets without sufficient domain coverage can be challenging. To solve these issues, we propose OpticNet, a novel optical refraction network based on an unsupervised, domain-specific loss function that explicitly incorporates physical information into the network. By providing a precise and differentiable light propagation eye model, physical gradients following the eye optics are backpropagated into the network. We further propose a new transfer learning procedure, which allows the unsupervised pre-training on the optical model and fine-tuning of the network on small amounts of surgical patient data. We show that our method outperforms the current state of the art on five OCT-image based data sets, provides better domain coverage within its predictions, and achieves better physical consistency.

Evaluation of a Novel Zonular Tension Restoring Accommodating Silicone IOL Design: Pilocarpine and Cyclopentolate-Induced Effect 20 Months after Implantation.

PURPOSE: To investigate a novel zonular-stress restoring accommodating 1-piece silicone IOL. Setting. Angeles City, Philippines. DESIGN: Prospective randomized bilateral study. METHODS: Each patient received a study IOL (ActaLens™, Emmetrope, La Canada, CA) in one eye and a control IOL (CrystaLens® AO, B&L, USA, or an AcrySof IQ®, Alcon, USA) in the contralateral eye to allow for intraindividual comparison. At the 20-month follow-up, two measurement days were set to measure all eyes before and after instilling 2% pilocarpine on the first day and 1% cyclopentolate on the second measurement day using an optical biometry device (Lenstar, Haag-Streit AG, Switzerland), respectively. PCO was graded by two examiners independently at the slit lamp. RESULTS: In total, 16 eyes of 8 patients were included. In the study group and the control group, the pilocarpine-induced ACD shift was 0.32 mm (SD: 0.12) (p=0.014) and 0.04 mm (SD: 0.16) (p=0.854), respectively. In the study group and the control group, the mean cyclopentolate-induced ACD shift was 0.14 (SD: 0.06) (p=0.014) and 0.03 mm (SD: 0.03) (p=0.181), respectively. PCO and Nd : YAG rates were higher in the study group, but differences were not found to be significant (AcrySof vs. ActaLens p=0.100 and CrystaLens vs. ActaLens p=0.174). CONCLUSION: The investigated IOL is a novel concept for an accommodating IOL, and results showed a moderate pilocarpine-induced forward shift of the IOL 20 months following implantation. For all patients, the investigated IOL seems to have a higher PCO rate compared to standard monofocal IOLs.

Digital ocular swept source optical coherence aberrometry.

Ocular aberrometry is an essential technique in vision science and ophthalmology. We demonstrate how a phase-sensitive single mode fiber-based swept source optical coherence tomography (SS-OCT) setup can be employed for quantitative ocular aberrometry with digital adaptive optics (DAO). The system records the volumetric point spread function at the retina in a de-scanning geometry using a guide star pencil beam. Succeeding test-retest repeatability assessment with defocus and astigmatism analysis on a model eye within ± 3 D dynamic range, the feasibility of technique is demonstrated in-vivo at a B-scan rate of >1 kHz in comparison with a commercially available aberrometer.

Impact of TCF4 Repeat Number on Resolution of Corneal Edema after Descemet's Stripping Only in Fuchs Dystrophy: A Pilot Study.

PURPOSE: To investigate whether Fuchs endothelial corneal dystrophy (FECD) genotype, specifically transcription factor 4 (TCF4) CTG triplet repeat "load" predicts time to clearance following Descemet's Stripping Only (DSO). METHODS: This prospective, interventional trial was conducted on consecutive FECD patients undergoing DSO. Genetic analysis using patients' saliva was performed to assess the extent of CTG expansion using short tandem repeat analysis, corroborated gel electrophoresis and Sanger sequencing. Polymerase chain reaction and bidirectional Sanger sequencing was undertaken. Partial least square regression and logistic regression modelling was used to evaluate the predictive power of TCF4 repeats on corneal clearance. RESULTS: Of 11 eyes of 11 patients, 8 showed complete corneal clearance. For these 8 patients, mean TCF4 allele repeat was 24.8 (SD: 23.7, range: 11-63) and 63.4 (SD: 30.3; range: 11-97), respectively. In total, 9/11 (81.8%) had expanded CTG repeats (>40) in one allele. In cases with an allele repeat ≥80, there was a significantly increased risk of corneal non-clearance (odds ratio 18.2, p = 0.009). CONCLUSION: Whilst it was not possible to predict time to corneal clearance based on CTG repeats, there is a significant correlation between allele repeats and achievement of corneal clearance.