Scheimpflug Imaging Research Articles

Multimodal corneal imaging before refractive cataract surgery.

To prospectively review the advances in diagnostics for refractive cataract surgery, focusing on multimodal corneal analysis. The article explores the considerations related to planning refractive cataract surgery, emphasizing its potential to enhance patients' vision performance and quality of life. This review explores preoperative analysis in cataract surgery, focusing on assessing the cornea and ocular surface using multimodal diagnostics, including Placido disk-based corneal topography, Scheimpflug tomography OCT (optical coherence tomography), and biomechanical assessment. Wavefront technology, gene therapy, and artificial intelligence are also relevant in enhancing surgical precision and outcomes. It highlights the importance of preoperative thorough evaluations and technological advancements in ophthalmology. The rapid evolution and advancement of technology enable excellent refractive outcomes in most cases following cataract surgery. Consideration of appropriate preoperative factors is essential for achieving the desired postoperative outcome.

Evaluation of parameters for early detection of pediatric keratoconus

BackgroundKeratoconus in children is often more severe and rapidly progressive compared to adults. While Scheimpflug imaging (Pentacam) improves screening, there are no established pediatric guidelines. Due to challenges in diagnosis, we aimed to correlate clinical factors with abnormal imaging results to aid in the development of screening protocols.MethodsA single-center retrospective cohort analysis of patients 3–18 years screened for keratoconus with ophthalmic examination and initial Scheimpflug imaging between 2021 to 2023. Scheimpflug indices including final D, ART max, and calculated CAIRO 8, which is a corneal metric combining pachymetry, ART max, and elevation, were compared to published pediatric ranges for normal and keratoconus corneas.ResultsSeventy-eight patients (11.8 ± 3.9 years) were screened with the majority referred due to high and/or progressive astigmatism (74 patients, 94%). Forty-nine patients (63%) were male and 48 (62%) self-reported Hispanic ethnicity. Average astigmatism was 4.9 ± 1.8 D and 86% had with-the-rule astigmatism. Fourteen patients (18%) had corneal findings on slit lamp. Average LogMAR CDVA was 0.243 ± 0.274 D. By Pentacam, 55 (70%) patients had ≥ 1 indeterminate or keratoconus value. Patients stratified as keratoconus by all parameters were older (15 vs. 11 years, p = 0.015–0.02), had worse visual acuity (p < 0.0001), and were more likely to have oblique astigmatism (0.0002—< 0.0001) and corneal abnormalities on examination (p < 0.00001) compared to eyes with normal or indeterminate indices.ConclusionsOlder age, lower visual acuity, oblique astigmatism, and corneal findings were more commonly found in patients with abnormal screening Pentacam. Most patients clinically suspicious for keratoconus had ≥ 1 indeterminate/abnormal indices. Future studies will follow these patients to identify clinical risk factors for progression.

Agreement in anterior segment measurements between swept-source optical coherence and dual Scheimpflug tomography devices in keratoconus eyes

PurposeTo evaluate the agreement of ocular biometry measured using a swept-source optical coherence (Casia 2) and a dual Scheimpflug (Galilei G6) tomography in keratoconus.MethodsThis retrospective study included 102 eyes from 102 keratoconus patient examined using both devices. Parameters compared included flat (Kf) and steep (Ks) keratometry, astigmatism of anterior, posterior, and total keratometry, central (CCT) and thinnest (TCT) corneal thickness. To assess the agreement, intraclass coefficient (ICC) and Bland-Altman analysis with 95% limits of agreement (LoA) were used.ResultsAnterior and total Ks and Kf showed moderate or good agreement with 95% limits of agreement (LoA) range over 9.75 D. Posterior Ks and Kf were lower in the Galilei G6 (all p < 0.001). Astigmatism showed moderate, poor, and moderate agreement for anterior, posterior, and total keratometry, respectively. CCT and TCT showed excellent agreement; however, the 95% LoA range was over 60 μm.ConclusionThe agreement between the two devices was not excellent for most parameters used to diagnose keratoconus and assess disease progression, and the differences were clinically significant. Therefore, the measurements from these two devices are not interchangeable for patients with keratoconus.

Cataract surgery with endothelial keratoplasty.

This review aims to provide an updated summary of the combined approach of cataract surgery with endothelial keratoplasty (EK), addressing key considerations, including intraocular lens (IOL) choice and calculation, decision between sequential and triple EK, and modifications in surgical techniques and postoperative management. Advances in imaging techniques (Scheimpflug tomography and anterior segment optical coherence tomography) have improved the ability to detect subclinical corneal edema, aiding in surgical decision-making for EK. Recent studies comparing sequential and triple-EK indicate that both methods yield similar visual outcomes. Though triple-EK offers quicker recovery, it may have higher complication rates. The use of gases like SF6 and C3F8 for anterior chamber tamponade is evolving, with conflicting findings on their efficacy in preventing graft detachment. Furthermore, IOL selection remains crucial, as hyperopic refractive surprises are common, and hydrophilic lenses should be avoided owing to the risk of opacification after EK. The combination of cataract surgery with EK has emerged as an effective treatment for patients with corneal endothelial diseases and cataract. Careful preoperative evaluation, appropriate IOL selection, and advances in surgical techniques contribute to better outcomes, although patient-specific factors must guide the choice between sequential and triple-EK procedures.

Agreement between a new fully automatic ocular biometer based on optical low-coherence reflectometry and an optical biometer based on Scheimpflug imaging combined with partial coherence interferometry

BackgroundTo analyze the difference and agreement between measurements obtained by a new fully automatic optical biometer, the SW-9000 μm Plus, based on optical low-coherence reflectometry (OLCR) and a commonly used optical biometer (Pentacam AXL) based on Scheimpflug imaging with partial coherence interferometry (PCI).MethodsThe central corneal thickness (CCT), anterior chamber depth (ACD, from epithelium to anterior lens surface), lens thickness (LT), mean keratometry (Km), corneal astigmatism, corneal diameter (CD), pupil diameter (PD), and axial length (AL) of 74 eyes (from 74 healthy subjects) were measured using the SW-9000 μm Plus and the Pentacam AXL to determine the agreement. Double angle plots were used for astigmatism vector analysis. Bland–Altman and 95% limits of agreement (LoA) were calculated.ResultsStatistically significant differences were detected for all parameters but J0 vector. The Bland–Altman analysis of AL, CCT, ACD, Km, CD, J0 and J45 indicated a high level of agreement between the two devices. Among AL, CCT, ACD, Km, J0, J45, CD, and PD, the 95% LoA ranged from -0.07 to 0.05 mm, -9.67 to 7.34 mm, -0.11 to 0.04 mm, -0.25 to 0.50 D, -0.22 to 0.20 D, -0.15 to 0.20 D, -0.23 to 0.35 mm and 1.55 to 3.77 mm, respectively.ConclusionsThe measurements of AL, CCT, ACD, Km, corneal astigmatism, and CD showed a narrow LoA and may be used interchangeably in healthy subjects between the new OLCR optical biometer and the Scheimpflug/PCI biometer; however, a poor agreement was noted for PD values.

Comparison of ocular biometric measurements and intraocular lens power calculation using different methods in eyes with implantable collamer lenses

This prospective cohort study included 80 healthy candidates for Implantable Collamer Lens (ICL) implantation who underwent biometric assessments with Scheimpflug imaging (the Pentacam-AXL) and swept-source optical coherence tomography (SS-OCT; the IOLMaster-700), both before and 3 months after surgery. The main outcome measures were mean keratometry, anterior chamber depth, axial length, and various intraocular lens (IOL) calculation formulas (Haigis, SRK/T, Hoffer Q, Holladay 1, Barrett Universal 2, and Olsen). The interchangeability of the devices was assessed by generating 95% limits of agreement (95% LoA) and associated Bland-Altman plots. The average age of the participants was 31.5 ± 5.4 years (22–43), with 58 (72.5%) being female. Among the cases analyzed, 11 (13.4%) had incorrect anterior lens surface segmentation using the IOLMaster-700, and 1 case (1.2%) had inappropriate segmentation using the Pentacam-AXL. Postoperative IOL power calculation resulted in readings that were, on average, 0.15 to 0.30 D higher compared to preoperative measurements. The 95% LoAs could differ by up to 0.85 D higher after surgery, indicating weak agreement between pre- and postoperative measurements. There was poor agreement between the IOLMaster-700 and Pentacam-AXL in IOL power calculation for eyes with post-ICL implantation, with a difference of more than 1 D in the 95% LoAs. In conclusion, Scheimpflug imaging was found to be less susceptible than the SS-OCT technique to segmentation errors of the anterior lens surface after ICL implantation. Neither device showed interchangeable results for pre- versus postoperative IOL power calculation. The determination of IOL power by the IOLMaster-700 versus Pentacam-AXL was not interchangeable in eyes with ICL implantation.

Non-orthogonal spectacle correction for irregular astigmatism.

To investigate the potential improvement in visual acuity and subjective perception of image quality in patients with keratoconus using non-orthogonal correction (NOC) cylinder trial lenses where the steep and flat power meridians are set at angles less or greater than 90°. A set of NOC plano/cylindrical trial lenses, where the axes between the power meridians were set at a range of non-orthogonal angles, were used to refract 18 participants with keratoconus in whom 23 eyes were used for testing. Corneal elevation data were processed by bespoke MATLAB code from Pentacam Scheimpflug tomographer scans. Each participant first underwent subjective refraction using standard orthogonal cylinder trial lenses, and the monocular best-corrected visual acuity (BCVA, logMAR) was recorded for each eye. They then underwent a second subjective refraction using NOC cylinder trial lenses created for the study and completed a questionnaire to elicit their subjective appraisal of letter clarity and ghosting. Fourteen (61%) eyes demonstrated an increase in objective BCVA with the NOC versus the orthogonal correction; seven (30%) eyes showed no change and in two (9%) eyes, the BCVA was slightly worse. Further, 87% and 79% experienced an increase in letter clarity and a reduction in ghosting, respectively, independent of changes in BCVA. The majority of non-orthogonal angles were in the range of 80°-85°, and it was possible to refine the cylinder and axis of the NOC further compared with the orthogonal correction. All but one of the participants said they would be interested in trying non-orthogonal spectacles if the opportunity arose. Correcting irregular astigmatism in keratoconic individuals with non-orthogonal spectacle correction may provide benefit in terms of increased visual acuity, improvements in letter clarity and a reduction of ghosting effects. This type of correction has the potential to improve the overall quality of life for patients with keratoconus.

Peripheral Iridectomy in Intrascleral Intraocular Lens Fixation: Preventing Reverse Pupillary Block

To compare clinical outcomes, reverse pupillary block (RPB) findings and anterior segment parameters in patients with and without intraoperative peripheral iridectomy during sutureless flattened flange intrascleral intraocular lens (IOL) fixation. Retrospective comparative case series. This study included 94 eyes of 82 patients who underwent IOL explantation due to vitreous-dislocated IOL at our clinic between March 2020 and September 2023, followed by flattened haptic-tipped IOL intrascleral fixation combined with pars plana vitrectomy (PPV). The patients were divided into two groups: Group 1 (n=54) underwent peripheral iridectomy during surgery, while Group 2 (n=40) did not undergo surgical peripheral iridectomy. Anterior chamber depth (ACD), anterior chamber angle (ACA) and white-to-white (WTW) distance were measured with Scheimpflug imaging. Visual outcomes, ACD, ACA, spherical equivalence (SE), intraocular pressure (IOP), complications, and secondary interventions were evaluated. There was no significant difference between the two groups preoperatively in terms of IOP, ACD, ACA, WTW distance, and axial length (p > 0.05). Postoperatively, the mean ACD was significantly less in Group 1 (3.79 ± 0.67 mm) than in Group 2 (4.11 ± 0.75 mm) (p = 0.03). Postoperative IOP was 15.51 ± 2.48 mmHg in group 1 and 18.20 ± 4.51 mmHg in group 2 (p < 0.001). The postoperative ACA was statistically significantly shallower in Group 1 (41.72 ± 3.47 degrees) than in Group 2 (52.45 ± 17.93 degrees) (p < 0.001). Postoperatively, RPB developed in 10 eyes (25.0%) in Group 2, while it was not observed in any patient in Group 1 (p < 0.001). In Group 2, pupillary capture developed in 4 cases (10%) in addition to RPB. Laser peripheral iridotomy was performed in cases with RPB. After laser peripheral iridotomy, mean IOP, mean ACA and ACD also decreased significantly (p < 0.001). Intraoperative peripheral iridectomy during scleral fixation surgery combined with PPV leads to significantly less RPB, a more stable anterior chamber, and fewer complications. Laser peripheral iridotomy was very useful in managing RPB that developed in the postoperative period.

Repeatability and agreement of two swept-source optical coherence tomographers and scheimpflug imaging for measurements of corneal curvature

PurposeTo evaluate the repeatability and agreement of two swept-source optical coherence tomographers and Scheimpflug imaging for corneal curvature in healthy subjects to obtain data on the clinical application of a new device.MethodsThis prospective study was conducted in January and February 2021 with 100 healthy subjects at the Eye Hospital of Wenzhou Medical University. Simulated keratometry (Sim-K), posterior keratometry (Kp), total corneal power (TCP), and total corneal astigmatism (TCA) were measured with CASIA2, Anterion, and Pentacam. Within-subject standard deviation (Sw), repeatability coefficient (RC), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were used to assess inter-device repeatability. Bland–Altman analysis was performed to determine inter-device agreement.ResultsThe three devices showed good repeatability for Sim-K, Kp, and TCP with all ICC > 0.980. Pentacam showed the highest repeatability (ICC ≥ 0.993; ICC ≥ 0.993) while the CASIA2 demonstrated the lowest repeatability (ICC: ≥ 0.986; ICC: ≥ 0.985) for Sim-K and TCP. Anterion and CASIA2 revealed better repeatability (ICC ≥ 0.998; ICC ≥ 0.981) for Kp than Pentacam (ICC ≥ 0.980). Pentacam and Anterion showed good repeatability for TCA (ICC: 0.935 and 0.916), whereas the CASIA2 showed moderate repeatability (ICC: 0.836). Three instruments demonstrated good agreement with the maximum absolute 95% Limits of agreement (LoA) of 1.00 D for Sim-K, Kp, and TCP. Wide LoA were found for TCA with the maximum absolute 95% LoA ≥ 0.66 D between the three devices.ConclusionsIn healthy subjects, the three devices (Pentacam, Anterion and CASIA2) displayed comparable repeatability and accuracy for SimK, Kp, and TCP, and could be used interchangeably for these parameters. However, TCA measured by the three devices was not interchangeable.Trial registrationChinese Clinical Trial Registry Center (10/10/2020, ChiCTR2000038959).

Comparison of a Scheimpflug imaging with other screening indices in diagnosing keratoconus and keratoconus suspect

Keratoconus (KC) is an irreversible blinding eye disease; therefore, early screening of KC suspects (KCS) is crucial for protecting patients’ quality of life. Scheimpflug imaging is a commonly used screening device in clinical practice. We aimed to evaluate the diagnostic ability of a Scheimpflug imaging device (Scansys) for KC and KCS and compared it with other Scheimpflug-based devices (Pentacam and Corvis ST). This prospective case-control study included 107 normal eyes, 72 KCS, and 57 KC. Scansys screening index Keratoconus probability (KCP) showed excellent performance in diagnosing KC at a cutoff value of 16.4 (area under the receiver operating characteristic [AUROC] = 1.000), with 100% sensitivity and 98.11% specificity. KCP had a better KCS diagnostic ability at a cutoff value of 8.9 (AUROC = 0.813) than Corvis biomechanical index (CBI, AUROC = 0.764), reaching 67.61% sensitivity and 85.85% specificity. Pentacam screening index Belin/Ambrósio enhanced ectasia display deviation (BAD-D) showed the best performance with 92.96% sensitivity and 89.62% specificity at a cutoff value of 1.525 (AUROC = 0.970) in diagnosing KCS. Scansys provides accurate KCP parameters in diagnosing KC; however, the efficiency of diagnosing KCS should be further optimized.

Binocular Scheimpflug light-field PIV

This work presents theoretical and experimental studies on a binocular Scheimpflug light-field based PIV. To investigate the effects of key parameters such as magnification, camera separation angle and tilt angle, a simulation study and quantitative comparison between conventional and binocular Scheimpflug light-field PIV have been performed. To validate the performance of binocular Scheimpflug light-field PIV, a series of vortex ring experiments have been carried out with different parameters. A comparison of the reconstructed volume and quality of the resolved vortex ring structures shows the advantages of binocular Scheimpflug light-field PIV. With Scheimpflug imaging, the focal plane of two light-field cameras can be fully overlapped which results in an extended reconstructed particle volume and less distortion in the resolved flow field than conventional binocular light-field PIV.

Descemet Endothelial Thickness Comparison Trial II (DETECT II): multicentre, outcome assessor-masked, placebo-controlled trial comparing Descemet membrane endothelial keratoplasty (DMEK) to Descemet stripping only (DSO) with adjunctive ripasudil for Fuchs dystrophy

IntroductionIt remains uncertain whether Descemet membrane endothelial keratoplasty (DMEK) or Descemet stripping only (DSO) yields better outcomes in patients with symptomatic Fuchs endothelial corneal dystrophy (FECD). This paper presents the...

Dysfunctional lens syndrome: a literature review

Introduction. The term “Dysfunctional Lens Syndrome” (DLS) refers to age-related changes in the lens, including early cataracts and presbyopia, that do not significantly reduce visual acuity. This syndrome is characterized by a decrease in accommodative amplitude, an increase in light scattering, and a reduction in contrast sensitivity. With rising life expectancy, the prevalence of DLS is increasing, necessitating a more in-depth study of the pathogenic mechanisms underlying the syndrome and the refinement of its diagnostic criteria to establish standards for treatment correction. Aim: to summarize information on the pathogenesis of DLS, the potential for staging the syndrome using objective examination methods, and to provide treatment recommendations. Materials and methods. A bibliographic study of scientific publications was conducted using the Pubmed, ScienceDirect, and Cyberleninka databases. Literature sources were searched using the following keywords: dysfunctional lens syndrome (DLS), presbyopia correction, cataract, age-related lens changes. A total of 32 publications, primarily from the last 10 years, were included in the study from more than 100 viewed sources. Results. The DLS encompasses a wide range of conditions, from early stages characterized by a loss of accommodative amplitude and minor refractive anomalies to later stages involving a decrease in visual acuity and quality due to increased light scattering and aberrations. Currently, the evaluation of age-related lens changes involves assessing visual acuity and determining the degree of lens opacification using slit-lamp examination. Additionally, objective instrumental methods, such as optical coherence tomography and Scheimpflug imaging, can be used to assess the degree of lens opacification. Various methods are employed for the correction and treatment of DLS, ranging from glasses and contact lenses to surgical interventions, such as lens extraction and intraocular lens implantation. Research is also ongoing into drugs aimed at slowing the progression of lens changes. Conclusion. The term “Dysfunctional Lens Syndrome” is currently used to describe early cataracts and presbyopia, where the reduction in visual acuity is still minor, but patients experience visual complaints due to age-related lens changes. Further research is necessary to develop and standardize diagnostic criteria and to evaluate the effectiveness of new treatment methods and interventions in order to create the most effective and adequate approach to correcting DLS and alleviating the associated visual complaints.

Corneal densitometry measurements comparison between anterior segment OCT and scheimpflug imaging

PurposeTo evaluate and compare the repeatability of corneal densitometry (CD) measurements obtained using both an anterior-segment optical coherence tomography (AS-OCT) device and a Scheimpflug camera system, while also assessing the level of agreement. The study also sought to investigate the correlation of CD with age, gender, and central corneal thickness (CCT) in normal eyes.MethodsCD measurements were obtained using the Casia 2 and the Pentacam AXL Wave. Data were collected on Total Corneal Densitometry and 4 concentric corneal annular areas, these are referred to as zone 1, denoting the central area, through to zone 4, designating the outermost peripheral region. Repeatability was assessed using intra-session test–retest variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). The agreement was evaluated using Bland–Altman plots. Correlation analysis was performed between CD, age, gender, and CCT.ResultsThe study included 96 healthy volunteers. The Casia 2 demonstrated high repeatability with ICC values exceeding 0.9 in all the corneal zones and lower CoV values compared to the Pentacam AXL Wave (ranging from 1.07% to 2.25% for Casia 2 and from 1.91% to 6.89% for Pentacam).95% LoA were within ± 2 standard deviation from the average mean except from zone 1 (± 2.42).However, the measurements showed a consistent bias among all the corneal zones. CD values were positively correlated with age, except for zone 1 with the Pentacam (p = 0.083).ConclusionsThe findings suggest that the Casia 2 can be a reliable tool for assessing corneal transparency in healthy individuals, however its measurements are not interchangeable with those provided by the Pentacam. The AS-OCT device may be more sensitive in detecting subtle age-related changes in CD within the central zone.

Comparison of measurements and calculated lens power using three biometers: a Scheimpflug tomographer with partial coherence interferometry and two swept source optical coherence tomographers

PurposeTo compare the biometric measurements obtained from the Pentacam AXL Wave, IOLMaster 700, and ANTERION and calculate the recommended intraocular lens power using the Barrett Formulae.MethodsThis was a retrospective cross-sectional study of patients who underwent biometry using the Pentacam AXL Wave, IOLMaster 700, and ANTERION. Flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), and axial length (AL) from each device were measured and compared. These parameters were used to calculate the recommended IOL powers using the Barrett formula.ResultsThe study included 252 eyes of 153 patients. The IOLMaster had the highest acquisition rate among the two biometers. The Pentacam obtained the shortest mean AL, the IOLMaster measured the highest mean keratometry values, and the ANTERION measured the highest mean ACD. In terms of pairwise comparisons, keratometry and axial length were not significantly different between the Pentacam-IOLMaster and ANTERION-IOLMaster groups, while the rest of the pairwise comparisons were statistically significant. In nontoric and toric eyes, 35–45% of patients recommended the same sphere of IOL power. In another 30–40%, the Pentacam and ANTERION recommended an IOL power one step greater than that of the IOLMaster-derived data. 50% of the study population recommended the same toric-cylinder IOL power.ConclusionsThe Pentacam AXL Wave, IOLMaster 700, and ANTERION can reliably provide data for IOL power calculations; however, these data are not interchangeable. In nontoric and toric eyes, 35–45% of cases recommended the same sphere IOL power, and in another 30–40%, the Pentacam and ANTERION recommended one-step higher IOL power than the IOLMaster-derived data. In targeting emmetropia, selecting the first plus IOL power is advisable when using the Pentacam and ANTERION to approximate the IOL power calculations recommended by the IOLMaster 700.

Corneal densitometry changes post-CXL for keratoconus: Comparative evaluation of epithelium-off, contact lens-assisted, and transepithelial techniques.

To evaluate changes in corneal backscattering after collagen cross-linking (CXL) for progressive keratoconus and compare its course with different techniques - standard epithelium-off CXL (SCXL), contact lens-assisted CXL (CACXL), and transepithelial CXL (TECXL). Advanced Eye Center, Post Graduate Institute of Medical Education and Research, Chandigarh, India. Retrospective comparative study. Ninety-four eyes (SCXL: 47, CACXL: 30, and TECXL: 17) were compared. Corneal haze was quantified using Scheimpflug tomography, pre- and post-CXL at 1, 3, 6, and 12 months. The baseline mean density score of the central anterior stromal layer was 16.14 ± 7.07, 15.85 ± 7.89 and 15.89 ± 7.21 in SCXL, CACXL, and TECXL groups, respectively (P 0.93). After SCXL, the score increased to 28.83 and 31.34 at 1 and 3 months, respectively (both P < 0.001) and dropped at 6 months (28.66, P < 0.001) and 12 months (23.72, P 0.003). Post-CACXL, the mean densitometry peaked at 3 months (20.35, P 0.14) and returned toward baseline at 6 months (18.82, P 0.15). After TECXL, it increased slightly at 1 month (18.47, P 0.17), decreased at 3 months (14.88, P 0.7), and plateaued over 1 year. No correlation with visual acuity was seen. Corneal haze increased significantly after SCXL, peaking at 3 months, declining over 6-12 months, and returning to baseline at 12 months. In contrast, post-TECXL and -CACXL, there was an insignificant increase in anterior corneal haze, which returned to baseline within 3-6 months.

Assessment of the Corneal Biomechanical Features of Sturge-Weber Syndrome Using Dynamic Ultrahigh-speed Scheimpflug Imaging.

To evaluate the corneal biomechanical characteristics of eyes with Sturge-Weber syndrome (SWS) secondary glaucoma (SSG) by analyzing corneal biomechanical parameters obtained using the Corneal Visualization Scheimpflug Technology instrument (Corvis ST). In patients with SWS, eyes affected by SSG were designated as the SSG group while the contralateral eyes were designated as the SWS contralateral group (SC group). Patients from the myopia clinic served as the control group. Dynamic corneal response parameters (DCRs) including the stress-strain index (SSI)-a critical material stiffness parameter that excludes interference from IOP and central corneal thickness (CCT)-were analyzed. For CCT, no significant difference was observed between the SSG and SC groups. However, significant differences were found between the SSG and control groups and between the SC and control groups. Parameters such as HC Time, A1 Deformation Amp., A2 Deformation Amp., length of Whole Eye Movement (WEM), DA Ratio Max (2 mm), PachySlope, DA Ratio Max (1 mm), and ARTh showed significant differences between the SSG group and control group. In the SSG group, 4 of night eyes had an SSI of less than 0.85. Some DCRs indicated a stiffer cornea in the SSG group, possibly due to a thicker cornea in this group. On analyzing SSI, it was found that corneal material properties change, becoming less stiff in some of the patients with SSG. In conclusion, our study provides a preliminary exploration of the biomechanical properties of SWS secondary glaucoma.

Cataract surgery with corneal endothelial pathology

Abstract: It is not uncommon for Fuch’s endothelial corneal dystrophy (FECD) patients to present with a co-existent cataract. Surgeons are often faced with a choice between simultaneous and staged corneal and cataract surgery. Descemet’s membrane endothelial keratoplasty (DMEK) has been found to have better visual outcomes as compared to Descemet’s stripping endothelial keratoplasty (DSEK) and penetrating keratoplasty and is currently the preferred surgery for FECD. Endothelial cell count and pachymetry cutoffs were earlier used for decision-making. Various other investigations such as Scheimpflug imaging and confocal microscopy are now used to prognosticate the outcome when performing cataract surgery only. Triple DMEK has the advantage of a definite treatment in a single sitting. Whereas, a staged approach with DMEK followed by cataract surgery has a better visual outcome. This is due to variable refractive changes in the cornea post-DMEK or DSEK that can lead to inaccurate intraocular lens (IOL) power calculation. Even though the graft detachment rates and rebubbling rates have been found to be comparable in triple DMEK versus a staged surgery, in view of increasing patient demands and expectations for a spectacle-independent outcome, a staged surgery is now preferable. Conventionally, surgeons favored the use of only monofocal lenses; however, the use of premium IOLs, especially extended depth of focus lenses, is now increasing. In this review, we will discuss the various advantages and disadvantages of a simultaneous and staged approach and pearls on decision-making in FECD with cataracts.

Pseudo Corneal Ectasia Due to Corneal Endothelial Disease

Purpose To describe two patients referred for presumed ectasia after laser in situ keratomileusis (LASIK) based on increasing myopia and corneal steepening years after LASIK. In both patients, further testing confirmed endothelial disease with central corneal edema as the cause of topographic changes. Methods Two patients showing symptoms similar to post-LASIK ectasia were assessed with Scheimpflug imaging (Pentacam; Oculus Optikgeräte GmbH) and subsequently treated with endothelial keratoplasty. Results Case 1 was a 66-year-old woman with increasing myopia after LASIK that was initially diagnosed as post-LASIK ectasia. Pentacam imaging revealed central corneal steep-ening with central corneal edema, and the clinical presence of guttata was consistent with Fuch's endothelial dystrophy. Case 2 was a 49-year-old man who also had increasing myopia and corneal steepening after LASIK, but no guttata. Pentacam imaging showed a similar pattern of central corneal swelling. Both patients underwent endothelial keratoplasty with reversal of corneal steepening. Conclusions Several conditions can mimic corneal ectasia, necessitating thorough clinical examination and tomography. This report describes two cases of central corneal edema resulting in myopia and corneal steepening that mimicked corneal ectasia. [ Journal of Refractive Surgery Case Reports. 2024;4(3):e24–e29.]

Recent Advances in Refractive Surgery: An Overview.

Refractive surgery has experienced substantial advancements over the past few years, driven by innovative techniques and continuous technological progress aimed at enhancing visual outcomes and patient satisfaction. Refractive errors such as myopia, hyperopia, and astigmatism affect a significant portion of the global population, impacting quality of life and productivity. Recent advancements have been fueled by a deeper understanding of ocular biomechanics and visual optics, leading to more precise and effective treatments. Traditional methods such as LASIK and PRK have been refined, and new procedures like SMILE (Small Incision Lenticule Extraction) have been introduced, expanding the range of treatable refractive errors and improving safety and predictability. Customized treatments, such as wavefront-guided LASIK and topography-guided PRK, allow for individualized plans tailored to each patient's unique corneal characteristics, enhancing visual acuity and reducing higher-order aberrations. The use of femtosecond lasers in procedures like Femto-LASIK and femtosecond laser-assisted cataract surgery (FLACS) offers unparalleled precision, reducing surgical risks and improving outcomes. Implantable Collamer Lenses (ICLs) and corneal crosslinking (CXL) have emerged as effective options for specific patient groups. Advanced diagnostic tools like optical coherence tomography (OCT) and Scheimpflug imaging have improved surgical planning and complication management. As research and technology continue to evolve, these advancements promise even greater improvements in refractive surgery, addressing the visual needs of the global population.