Unilateral intraindividual comparison and bilateral performance of a monofocal spherical and diffractive extended depth of field intraocular lens mix-and-match approach.

BACKGROUND: To evaluate the intraindividual visual performance of a spherical and extended depth of field (EDOF) IOL used in a mix-and-match approach. METHODS: Single centre (tertiary care centre), retrospective consecutive case series. Included patients had uneventful cataract surgery with implantation of a spherical monofocal IOL (CT Spheris 204) in the dominant eye and a diffractive EDOF IOL (AT LARA 829) in the non-dominant eye. Monocular and binocular defocus curves and visual acuity at various distances were assessed. In addition, binocular reading speed, contrast sensitivity, and patient satisfaction using QOV, Catquest 9SF, and glare/halo questionnaires are reported. RESULTS: A total of 29 patients (58 eyes) were included. We observed significant intra-individual differences for monocular DCIVA, DCNVA, UIVA, and UNVA. There were no differences in monocular BCDVA or UDVA. The monocular defocus curves for the two IOLs significantly differed at defocus steps between -1.0 and -3.5 D. 93.10% of patients reported they would opt for the same combination of IOLs. CONCLUSION: Excellent uncorrected and corrected distance visual acuity was demonstrated in both groups. The mix-and-match approach described in this study yielded good intermediate vision and improved near vision with high-patient satisfaction.

Enhancing Scleral Buckling Surgery Using an Illuminated Scleral Depressor.

PURPOSE: To report a technique for scleral buckling surgery under the operating microscope with wide-field viewing. METHODS: The identification and reliable marking of retinal breaks is one of the key steps for successful surgery in scleral buckling. For sufficient visualization of retinal breaks, some kind of indentation and illumination is necessary. In this technique, one instrument (Visible Periphery illuminated scleral indentor; Oertli Instrumente AG, Switzerland) combines scleral depression, illumination, and color marking (using a surgical marking pen) of the corresponding sclera above the retinal break. RESULTS: The illuminated scleral depressor enables the surgeon to safely and precisely mark the retinal break while stabilizing and rotating the eye with the other hand. This technique simplifies scleral buckling surgery by improving the handling and visualization of marking retinal breaks at the corresponding scleral. Neither intraoperative indirect ophthalmoscopy nor sclerotomies for chandelier light systems or any intraocular instrument are necessary. CONCLUSION: The illuminated scleral depressor facilitates scleral buckling surgery in a convenient way for easy and precise scleral marking of the retinal breaks even in challenging situations and positions of retinal breaks under the operating microscope with wide-field viewing. Indirect ophthalmology or other illumination sources are no longer needed.

Meridional ocular magnification after cataract surgery with toric and non-toric intraocular lenses.

BACKGROUND: Overall ocular magnification (OOM) and meridional ocular magnification (MOM) with consequent image distortions have been widely ignored in modern cataract surgery. The purpose of this study was to investigate OOM and MOM in a general situation with an astigmatic refracting surface. METHODS: From a large dataset containing biometric measurements (IOLMaster 700) of both eyes of 9734 patients prior to cataract surgery, the equivalent (PIOLeq) and cylindric power (PIOLcyl) were derived for the HofferQ, Haigis, and Castrop formulae for emmetropia. Based on the pseudophakic eye model, OOM and MOM were extracted using 4 × 4 matrix algebra for the corrected eye (with PIOLeq/PIOLcyl (scenario 1) or with PIOLeq and spectacle correction of the residual refractive cylinder (scenario 2) or with PIOLeq remaining the residual uncorrected refractive cylinder (blurry image) (scenario 3)). In each case, the relative image distortion of MOM/OOM was calculated in %. RESULTS: On average, PIOLeq/PIOLcyl was 20.73 ± 4.50 dpt/1.39 ± 1.09 dpt for HofferQ, 20.75 ± 4.23 dpt/1.29 ± 1.01 dpt for Haigis, and 20.63 ± 4.31 dpt/1.26 ± 0.98 dpt for Castrop formulae. Cylindric refraction for scenario 2 was 0.91 ± 0.70 dpt, 0.89 ± 0.69 dpt, and 0.89 ± 0.69 dpt, respectively. OOM/MOM (× 1000) was 16.56 ± 1.20/0.08 ± 0.07, 16.56 ± 1.20/0.18 ± 0.14, and 16.56 ± 1.20/0.08 ± 0.07 mm/mrad with HofferQ; 16.64 ± 1.16/0.07 ± 0.06, 16.64 ± 1.16/0.18 ± 0.14, and 16.64 ± 1.16/0.07 ± 0.06 mm/mrad with Haigis; and 16.72 ± 1.18/0.07 ± 0.05, 16.72 ± 1.18/0.18 ± 0.14, and 16.72 ± 1.18/0.07 ± 0.05 mm/mrad with Castrop formulae. Mean/95% quantile relative image distortion was 0.49/1.23%, 0.41/1.05%, and 0.40/0.98% for scenarios 1 and 3 and 1.09/2.71%, 1.07/2.66%, and 1.06/2.64% for scenario 2 with HofferQ, Haigis, and Castrop formulae. CONCLUSION: Matrix representation of the pseudophakic eye allows for a simple and straightforward prediction of OOM and MOM of the pseudophakic eye after cataract surgery. OOM and MOM could be used for estimating monocular image distortions, or differences in overall or meridional magnifications between eyes.

Case report: atypical, unilateral optic nerve infiltration as the first sign of acute lymphoblastic leukemia (ALL) relapse.

BACKGROUND: We describe a case of an atypical presentation of leukemic optic nerve infiltration. CASE PRESENTATION: A patient with acute lymphoblastic leukemia (ALL) in remission suffered from sudden right eye vision loss. At the time of presentation, the affected eye presented with an afferent pupillary defect, while the fundus examination was normal. A complete work up of the patient revealed no signs of ALL relapse, but MR imaging of the optic nerve showed contrast agent uptake consistent with optic nerve infiltration. The patient developed a fulminant ALL relapse and died shortly after. Histology of the optic nerve showed a leukemic infiltration with CD10 positive cells. CONCLUSIONS: This is the first report of an ALL relapse in the optic nerve without intraocular signs. Patients' medical history should therefore be taken into consideration in patients with unclear vision loss.

Efficacy of a Disease Management Program of a Tertiary Center and Ophthalmologic Practitioners for the Treatment of Neovascular Age-Related Macular Degeneration.

PURPOSE: The aim of the study was to examine real-world data of patients with neovascular age-related macular degeneration (nAMD) within a disease management program (DMP) treated with anti-VEGF. METHODS: A monocentric, retrospective chart review of 379 eyes of a local DMP was conducted at the Department of Ophthalmology, Kepler University Clinic Linz. Eyes were treated either with bevacizumab or aflibercept using a pro re nata scheme, consisting of 3 injections every 4 weeks in case of presence of disease activity. The observational period was up to 24 months. Disease activity was monitored by visual acuity (VA), clinical examination, and optical coherence tomography (OCT). For (re-)treatments, ophthalmologic practitioners referred patients directly to the intravitreal injection, avoiding redundant examinations. RESULTS: VA improved significantly for all patients after 2 months (logMAR 0.47 ± 0.36; p = 0.000) compared to baseline (0.55 ± 0.37), and for the aflibercept group for up to 6 months (0.36 ± 0.27; p = 0.018). After 12 months, VA remained stable without further significant improvement and decreased by 24 months compared to baseline. The median number of injections was 6 over the first 12 months and 4 in the second year. CONCLUSION: Data revealed the efficacy of a DMP for nAMD involving both ophthalmologic practitioners and a tertiary center. Avoiding redundant examinations increased the efficacy of a clinical setting.

Retinal Organoids and Retinal Prostheses: An Overview.

Despite the progress of modern medicine in the last decades, millions of people diagnosed with retinal dystrophies (RDs), such as retinitis pigmentosa, or age-related diseases, such as age-related macular degeneration, are suffering from severe visual impairment or even legal blindness. On the one hand, the reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) and the progress of three-dimensional (3D) retinal organoids (ROs) technology provide a great opportunity to study, understand, and even treat retinal diseases. On the other hand, research advances in the field of electronic retinal prosthesis using inorganic photovoltaic polymers and the emergence of organic semiconductors represent an encouraging therapeutical strategy to restore vision to patients at the late onset of the disease. This review will provide an overview of the latest advancement in both fields. We first describe the retina and the photoreceptors, briefly mention the most used RD animal models, then focus on the latest RO differentiation protocols, carry out an overview of the current technology on inorganic and organic retinal prostheses to restore vision, and finally summarize the potential utility and applications of ROs.

In Vitro Cytotoxicity of D18 and Y6 as Potential Organic Photovoltaic Materials for Retinal Prostheses.

Millions of people worldwide are diagnosed with retinal dystrophies such as retinitis pigmentosa and age-related macular degeneration. A retinal prosthesis using organic photovoltaic (OPV) semiconductors is a promising therapeutic device to restore vision to patients at the late onset of the disease. However, an appropriate cytotoxicity approach has to be employed on the OPV materials before using them as retinal implants. In this study, we followed ISO standards to assess the cytotoxicity of D18, Y6, PFN-Br and PDIN individually, and as mixtures of D18/Y6, D18/Y6/PFN-Br and D18/Y6/PDIN. These materials were proven for their high performance as organic solar cells. Human RPE cells were put in direct and indirect contact with these materials to analyze their cytotoxicity by the MTT assay, apoptosis by flow cytometry, and measurements of cell morphology and proliferation by immunofluorescence. We also assessed electrophysiological recordings on mouse retinal explants via microelectrode arrays (MEAs) coated with D18/Y6. In contrast to PFN-Br and PDIN, all in vitro experiments show no cytotoxicity of D18 and Y6 alone or as a D18/Y6 mixture. We conclude that D18/Y6 is safe to be subsequently investigated as a retinal prosthesis.

Toric phakic IOLs in keratoconus-evaluation of preoperative parameters on the outcome of phakic anterior chamber lens implantation in patients with keratoconus.

PURPOSE: To evaluate the influence of the type of the keratectasia and preoperative keratometry readings on the efficacy of implantation of iris-fixated phakic anterior chamber intraocular lenses (pIOL) in patients with keratoconus. METHODS: In this retrospective study, iris-fixated pIOLs (Artisan/Artiflex (Ophtec®), Verisyse/Veriflex (AMO®)) were implanted in 38 eyes of 22 patients with stable keratoconus. Thirty-six eyes underwent corneal crosslinking (CXL) prior to the lens implantation. The refractive outcome was evaluated 6 weeks postoperatively and the influence of preoperative refraction and topo- and tomographical factors were analyzed. RESULTS: The mean postoperative uncorrected distance visual acuity (UDVApost) was 0.25 ± 0.15 logMAR and was not statistically different from the mean preoperative corrected distance visual acuity (CDVApre), which was 0.24 ± 0.13 logMAR. Twenty-seven eyes (71%) reached UDVApost/CDVApre ≥ 1 (efficacy index), whereas patients with PMD-like ectasia (n = 14) showed significantly (p = 0.003) higher efficacy index (100%) than patients diagnosed with keratoconus (n = 24) (54%). Higher eccentricity of the maximum posterior elevation showed a significant beneficial influence on the efficacy index (p = 0.021). Furthermore, a higher Amsler-Krumeich stage and preoperative MAE were correlated with a worse UDVApost. The mean absolute spherical equivalent was significantly decreased from 5.71 ± 4.96 D to 1.25 ± 1.20 D (p < 0.001). No significant difference was found in endothelial cell count. CONCLUSION: The results indicate that the implantation of phakic iris-fixated anterior chamber IOLs is a reasonable refractive option for patients with keratoconus. Keratoconus patients with a pellucidal marginal degeneration (PMD)-like appearance ectasia seem to benefit most from such procedures.

Influence of ACPA-positive rheumatoid arthritis on visual field testing in patients with arterial hypertension: A comparative cross-sectional study.

PURPOSE: To evaluate a possible influence of anti-cyclic citrullinated peptide autoantibodies (ACPA) - positive rheumatoid arthritis (RA) on visual field (VF) testing in patients with arterial hypertension (aHT). METHODS: We conducted an observational cross-sectional study comparing patients with ACPA-positive RA and aHT, patients with aHT and healthy subjects. Further inclusion criteria were visual acuity (VA) of 0.8 or better and age between 40 and 60 years. VF testing was performed with standard automated achromatic perimetry (SAP), short wavelength automated perimetry (SWAP) (Octopus 300® ) and flicker perimetry (Pulsar® ). Results were analysed for a possible correlation with blood pressure or RA-activity. RESULTS: Twenty subjects with RA and aHT, 26 patients with aHT and 22 healthy participants were examined. Significant differences were found for mean sensitivity (MS) in SWAP comparing RA-patients with healthy participants (ΔMS -3.06, p = 0.001) and with hypertensive patients (ΔMS -2.32, p = 0.007). In SAP we observed a significant difference between patients with RA and healthy subjects regarding loss variance (LV) (ΔLV = +9.77, p = 0.004). Flicker perimetry did not demonstrate significant differences between groups. A correlation of VF changes with blood pressure level or RA-activity was not observed. CONCLUSION: Patients with ACPA-positive RA and aHT showed significant impairment of VF performance in SWAP compared to patients with aHT alone and healthy subjects. SAP also revealed a significant difference of LV between RA-patients and healthy subjects. aHT does not seem to induce functional changes in VF testing alone.

Vascular Aspects in Glaucoma: From Pathogenesis to Therapeutic Approaches.

Glaucomatous optic neuropathies have been regarded as diseases caused by high intraocular pressure for a long time, despite the concept of vascular glaucoma dating back to von Graefe in 1854. Since then, a tremendous amount of knowledge about the ocular vasculature has been gained; cohort studies have established new vascular risk factors for glaucoma as well as identifying protective measures acting on blood vessels. The knowledge about the physiology and pathophysiology of the choroidal, retinal, as well as ciliary and episcleral circulation has also advanced. Only recently have novel drugs based on that knowledge been approved for clinical use, with more to follow. This review provides an overview of the current vascular concepts in glaucoma, ranging from novel pathogenesis insights to promising therapeutic approaches, covering the supply of the optic nerve head as well as the aqueous humor production and drainage system.

RETINAL MORPHOMETRY CHANGES MEASURED WITH SPECTRAL DOMAIN-OPTICAL COHERENCE TOMOGRAPHY AFTER PAN-RETINAL PHOTOCOAGULATION IN PATIENTS WITH PROLIFERATIVE DIABETIC RETINOPATHY.

PURPOSE: To identify the effects of pan-retinal laser treatment on the integrity of neurosensory retinal layers. METHODS: Patients were examined with fluorescence angiography after a standardized examination for diabetic retinopathy and a peripapillary ring scan with spectral domain optical coherence tomography. A single-session pan-retinal photocoagulation was performed using the PASCAL pattern scanning argon laser applying a minimum of 1,500 spots. Optical coherence tomography was evaluated more than 6 months. RESULTS: Eighteen eyes of 12 consecutive patients with new onset, treatment-naive proliferative diabetic retinopathy secondary to diabetes Type 2 were treated and retinal optical coherence tomography morphology evaluated. Retinal nerve fiber layer thickness increased statistically significantly from baseline to week 1, when it reached its peak. The combined thickness of the outer plexiform and the inner nuclear layers and the combined thickness of the inner plexiform and the ganglion cell layers showed no relevant changes. The combined thickness of the retinal pigment epithelium and the photoreceptor cell layers decreased at month 1 followed by a steady increase in thickness, which remained below baseline values over time. CONCLUSION: Pan-retinal photocoagulation in proliferative diabetic retinopathy leads to a slowly reversible, marked biological response with statistically significant morphometric changes detected by spectral domain optical coherence tomography. Swelling of the retinal nerve fiber and outer nuclear layers induce an increase in peripapillary total retinal thickness. Simultaneously, the photoreceptor and retinal pigment epithelium layers decrease in thickness. These changes indicate diffuse retinal inflammation after pan-retinal laser therapy.

Refractive changes after pharmacologic resolution of diabetic macular edema.

PURPOSE: To determine precisely the mean change in refractive power induced by treatment in patients with diabetic macular edema (DME). DESIGN: Prospective, randomized study. PARTICIPANTS: Fifty eyes of 50 consecutive patients with clinically significant macular edema receiving all 3 types of current state-of-the-art treatment with intravitreal antiedematous substances (ranibizumab, bevacizumab, or triamcinolone). METHODS: Patients were followed up at monthly intervals and were treated following a standardized pro re nata regimen according to protocol. Best-corrected visual acuity (BCVA) was determined by certified visual acuity examiners. The refractive power of the treated eyes was determined using a push-plus technique. The change in refraction between baseline and the visit when the macula was completely dry or when the central subfield thickness (CST) measured by optical coherence tomography had reached the thinnest level was analyzed. MAIN OUTCOME MEASURES: Spherical equivalent refraction (SER) and CST. RESULTS: Fifty eyes of 50 patients received intravitreal therapy using ranibizumab (n = 11), bevacizumab (n = 20), or triamcinolone (n = 19). Mean BCVA was 0.33±0.23 logarithm of the minimum angle of resolution (logMAR) and mean CST was 492±130 µm. The mean SER was 0.41±2.06 diopters (D) at baseline. The BCVA at the time of optimal retinal morphologic features was 0.24±0.2 logMAR, mean CST was 300±78 µm, and mean change in SER was -0.01±0.46 D. Changes is BCVA and CST were statistically significant (P < 0.0001), but the SER change was not (P = 0.824). CONCLUSIONS: Appropriate spectacle correction can be prescribed to patients with DME any time during ongoing therapy using antiedematous substances because resolution of retinal thickening is not associated with an increased risk of a myopic shift.

Morphologic parameters relevant for visual outcome during anti-angiogenic therapy of neovascular age-related macular degeneration.

PURPOSE: To identify the effects of anti-angiogenic therapy in neovascular age-related macular degeneration (AMD) in respect to morphologic type and time course and to identify prognostic factors for visual outcome on the basis of standardized optical coherence tomography (OCT) analysis. DESIGN: Subanalysis of a prospective, 12-month, multicenter, phase IIIb trial (Efficacy and Safety of Ranibizumab in Patients with Subfoveal Choroidal Neovascularization Secondary to Age-Related Macular Degeneration [EXCITE]). PARTICIPANTS: A total of 353 treatment-naïve patients with subfoveal choroidal neovascularization (CNV) receiving quarterly or monthly ranibizumab therapy. METHODS: Patients were randomized to receive 0.3 mg quarterly, 0.5 mg quarterly, or 0.3 mg monthly doses of ranibizumab. Treatment comprised a loading phase of 3 consecutive monthly injections followed by a 9-month maintenance phase of monthly or quarterly injections. Best-corrected visual acuity (BCVA) was measured using the Early Treatment Diabetic Retinopathy Study protocol, and retinal morphology was assessed by Stratus OCT (Carl Zeiss Meditec, Dublin, CA). Imaging data were evaluated by certified examiners of the Vienna Reading Center using a standardized protocol. MAIN OUTCOME MEASURES: The BCVA was measured using ETDRS charts and retinal morphology was assessed by OCT. RESULTS: During the loading phase, there was a significant correlation between a reduction in central retinal thickness and an increase in BCVA (P < 0.001), which decreased during the maintenance phase in all treatment arms. The proportion of patients showing retinal morphologic changes, such as intraretinal cysts (IRCs), subretinal fluid (SRF), and pigment epithelial detachments (PEDs), decreased significantly in all groups (P < 0.001), more intensively in the 0.5 mg quarterly than in both 0.3 mg groups. Intraretinal cysts resolved most rapidly followed by SRF, whereas PED decreased at a slower rate and intensity. Patients with IRC at baseline had lower BCVA levels that remained lower over the entire study period, whereas recurrence of IRC during follow-up showed no additional negative effect on function. Baseline SRF had no effect on visual recovery; however, recurrence of SRF during follow-up showed a tendency for an additional negative effect on function (P = 0.06). Baseline PED showed a negative influence on visual outcome only in combination with IRC and SRF. CONCLUSIONS: There is a distinct response pattern and time course of morphologic parameters associated with anti-vascular endothelial growth factor therapy in neovascular AMD. Specific alterations, such as IRC, SRF, and PED, as baseline or follow-up features are significantly influencing the potential for visual gain.

Distribution of intraretinal exudates in diabetic macular edema during anti-vascular endothelial growth factor therapy observed by spectral domain optical coherence tomography and fundus photography.

PURPOSE: To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema. METHODS: Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography. RESULTS: Before treatment, microexudates were detected by SD-OCT as hyperreflective foci in 24 eyes, whereas HEs were seen in 22 eyes. During therapy, HE increased significantly in number and size. This was accompanied by accumulation of microexudates in the outer retina. Enlargement of hyperreflective structures in SD-OCT was accompanied by enlargement of HE at corresponding fundus locations. A rapid reduction in diabetic macular edema was seen in all patients, but to varying degrees. Patients with hemoglobin A1c levels <7% and serum cholesterol <200 mg/dL formed fewer HEs and featured more edema reduction and visual acuity gain. CONCLUSION: Diabetic macular edema reduction during intravitreal anti-vascular endothelial growth factor therapy was accompanied by dynamic rearrangement of intraretinal exudates at corresponding locations in fundus photography and SD-OCT. Intraretinal aggregates of microexudates detectable as hyperreflective foci by SD-OCT may compose and precede HE before they become clinically visible.

Differential diagnosis of macular edema of different pathophysiologic origins by spectral domain optical coherence tomography.

PURPOSE: To develop a classification approach based solely on spectral domain optical coherence tomography to differentiate macular edema (ME) of different disease entities and to determine underlying pathology. METHODS: A cross-sectional study including 153 participants: 27 with Irvine-Gass, 31 with uveitic ME, 24 with ME after branch retinal vein occlusion, 13 with central retinal vein occlusion, 44 with diabetic ME, and 14 controls. Spectral domain optical coherence tomography was graded according to a standardized reading protocol. Grading characteristics were: ME pattern in the central line (horizontal/vertical) and in volume scans, distribution of cysts in Early Treatment Diabetic Retinopathy Study grid, morphologic features, and quantitative parameters such as individual layer thickness. The parameters in a best-fitting multivariate model were evaluated for reliability to predict the underlying pathology using a leave-one-out crossover-validation analysis. To evaluate clinical reliability, two masked clinicians graded spectral domain optical coherence tomography images according to the assessed parameters. RESULTS: The best-fitting multivariate model revealed that microfoci, ME pattern in vertical line scan, and foveal retinal nerve fiber layer thickness are the best indicators of the underlying pathology of ME. Classification accuracy of this model was 96%, mean cross-validated test classification accuracy was 84% (r² = 0.95, P < 0.0001). Clinical relevance was examined with 2 independent readers, yielding classification accuracies of 86% in both cases. CONCLUSION: Macular edema demonstrates characteristic patterns, morphologic features, and layer thicknesses dependent on the underlying disease process. Diagnostic recognition of these features may allow clinical and automated disease identification based primarily on spectral domain optical coherence tomography analysis.

Impact of uncertainties in biometric parameters on intraocular lens power formula predicted refraction using a Monte-Carlo simulation.

PURPOSE: The purpose of this study was to investigate the uncertainty in the formula predicted refractive outcome REFU after cataract surgery resulting from measurement uncertainties in modern optical biometers using literature data for within-subject standard deviation Sw. METHODS: This Monte-Carlo simulation study used a large dataset containing 16 667 preoperative IOLMaster 700 biometric measurements. Based on literature Sw values, REFU was derived for both the Haigis and Castrop formulae using error propagation strategies. Using the Hoya Vivinex lens (IOL) as an example, REFU was calculated both with (WLT) and without (WoLT) consideration of IOL power labelling tolerances. RESULTS: WoLT the median REFU was 0.10/0.12 dpt for the Haigis/Castrop formula, and WLT it was 0.13/0.15 dpt. WoLT REFU increased systematically for short eyes (or high power IOLs), and WLT this effect was even more pronounced because of increased labelling tolerances. WoLT the uncertainty in the measurement of the corneal front surface radius showed the largest contribution to REFU, especially in long eyes (and low power IOLs). WLT the IOL power uncertainty dominated in short eyes (or high power IOLs) and the uncertainty of the corneal front surface in long eyes (or low power IOLs). CONCLUSIONS: Compared with published data on the formula prediction error of refractive outcome after cataract surgery, the uncertainty of biometric measures seems to contribute with ⅓ to ½ to the entire standard deviation. REFU systematically increases with IOL power and decreases with axial length.

Continuous Detection of Stimulus Brightness Differences Using Visual Evoked Potentials in Healthy Volunteers with Closed Eyes.

Background/Objectives: We defined the value of a machine learning algorithm to distinguish between the EEG response to no light or any light stimulations, and between light stimulations with different brightnesses in awake volunteers with closed eyelids. This new method utilizing EEG analysis is visionary in the understanding of visual signal processing and will facilitate the deepening of our knowledge concerning anesthetic research. Methods: X-gradient boosting models were used to classify the cortical response to visual stimulation (no light vs. light stimulations and two lights with different brightnesses). For each of the two classifications, three scenarios were tested: training and prediction in all participants (all), training and prediction in one participant (individual), and training across all but one participant with prediction performed in the participant left out (one out). Results: Ninety-four Caucasian adults were included. The machine learning algorithm had a very high predictive value and accuracy in differentiating between no light and any light stimulations (AUCROCall: 0.96; accuracyall: 0.94; AUCROCindividual: 0.96 ± 0.05, accuracyindividual: 0.94 ± 0.05; AUCROConeout: 0.98 ± 0.04; accuracyoneout: 0.96 ± 0.04). The machine learning algorithm was highly predictive and accurate in distinguishing between light stimulations with different brightnesses (AUCROCall: 0.97; accuracyall: 0.91; AUCROCindividual: 0.98 ± 0.04, accuracyindividual: 0.96 ± 0.04; AUCROConeout: 0.96 ± 0.05; accuracyoneout: 0.93 ± 0.06). The predictive value and accuracy of both classification tasks was comparable between males and females. Conclusions: Machine learning algorithms could almost continuously and reliably differentiate between the cortical EEG responses to no light or light stimulations using visual evoked potentials in awake female and male volunteers with eyes closed. Our findings may open new possibilities for the use of visual evoked potentials in the clinical and intraoperative setting.

Predicting intraocular lens tilt using a machine learning concept.

PURPOSE: To use a combination of partial least squares regression and a machine learning approach to predict intraocular lens (IOL) tilt using preoperative biometry data. SETTING: Kepler University Clinic Linz, Linz, Austria. DESIGN: Prospective single-center study. METHODS: Optical coherence tomography, autorefraction, and subjective refraction were performed at baseline and 8 weeks after cataract surgery. In analysis I, only 1 eye per patient was included and a tilt prediction model was generated. In analysis II, a pairwise comparison between right and left eyes was performed. RESULTS: In analysis I, 50 eyes of 50 patients were analyzed. Difference in amount, orientation, and vector from preoperative to postoperative lens tilt was -0.13 degrees, 2.14 degrees, and 1.20 degrees, respectively. A high predictive power (variable importance for projection [VIP]) for postoperative tilt prediction was found for preoperative tilt (VIP = 2.2), pupil decentration (VIP = 1.5), lens thickness (VIP = 1.1), axial eye length (VIP = 0.9), and preoperative lens decentration (VIP = 0.8). These variables were applied to a machine learning algorithm resulting in an out of bag score of 0.92 degrees. In analysis II, 76 eyes of 38 patients were included. The difference of preoperative to postoperative IOL tilt of right and left eyes of the same individual was statistically relevant. CONCLUSIONS: Postoperative IOL tilt showed excellent predictability using preoperative biometry data and a combination of partial least squares regression and a machine learning algorithm. Preoperative lens tilt, pupil decentration, lens thickness, axial eye length, and preoperative lens decentration were found to be the most relevant parameters for this prediction model.