A Simple Pre-Operative Nuclear Classification Score (SPONCS) for Grading Cataract Hardness in Clinical Studies

Quantitative Evaluation of Human Lens and Lens Capsule Elasticity by Optical Coherence Elastography Based on a Rayleigh Wave Model

Evaluating the biomechanical properties of the lens and lens capsule is important for the clinical diagnosis and treatment of age-related cataracts and presbyopia. In this study, we developed an optical coherent elastography technique to assess the elasticity of the lens and lens capsule in the human eye. With age, the mean Young's modulus of the lens increased from 12.28 ± 0.87 kPa to 18.59 ± 1.45 kPa, and the lens capsule increased from 6.33 ± 0.36 kPa to 13.33 ± 0.74 kPa. The results showed that the Young's modulus of the lens capsule and lens increased with age, with the Young's modulus of the lens significantly higher than that of the lens capsule. This study reports the assessment of the elasticity of the human lens and lens capsule by the OCE technique, indicating that it may provide a potential clinical tool for advancing research on diseases affecting the lens.

Metabolomic Disparities in Intraocular Fluid Across Varied Stages of Cataract Progression: Implications for the Analysis of Cataract Development

Introduction: The lens's metabolic demands are met through a continuous circulation of aqueous humor, encompassing a spectrum of components such as organic and inorganic ions, carbohydrates, glutathione, urea, amino acids, proteins, oxygen, carbon dioxide, and water. Metabolomics is a pivotal tool, offering an initial insight into the complexities of integrated metabolism. In this investigative study, we systematically scrutinize the composition of intraocular fluid in individuals afflicted with cataracts. Methods: The investigation involved a comprehensive analysis of aqueous humor samples from a cohort comprising 192 patients. These individuals were stratified by utilizing the SPONCS classification system, delineating distinct groups characterized by the hardness of cataracts. The analytical approach employed targeted quantitative metabolite analysis using HILIC-based liquid chromatography coupled with high-resolution mass spectrometric detection. The metabolomics data analysis was performed with MetaboAnalyst 5.0. Results: The results of the enrichment analysis have facilitated the inference that the discerned disparities among groups arise from disruptions in taurine and hypotaurine metabolism, variations in tryptophan metabolism, and modifications in mitochondrial beta-oxidation of short-chain saturated fatty acids and pyrimidine metabolism. Conclusion: A decline in taurine concentration precipitates diminished glutathione activity, prompting an elevated requirement for NAD+ and instigating tryptophan metabolism along the kynurenine pathway. Activation of this pathway is additionally prompted by interferon-gamma and UV radiation, leading to the induction of IDO. Concurrently, heightened mitochondrial beta-oxidation signifies a distinctive scenario in translocating fatty acids into the mitochondria, enhancing energy production.

Outcomes of bent ab interno needle goniectomy with phacoemulsification in moderate to severe primary open angle glaucoma

PURPOSE

To assess the safety and efficacy of bent ab interno needle goniectomy (BANG) in moderate to severe primary open angle glaucoma (POAG) eyes undergoing phacoemulsification (phaco).

DESIGN

Single-arm, prospective, interventional study.

METHODS

POAG patients with medically uncontrolled intraocular pressure (IOP), >15 mmHg for moderate and >12 mmHg for severe POAG, with visually significant cataract were recruited. All patients underwent BANG using a 26-gauge needle to excise 30° of the trabecular meshwork, along with phaco. Primary outcome was IOP. Secondary outcomes were success rate, percentage reduction in IOP/antiglaucoma medications (AGMs), and intraoperative complications. Success at 12 months was defined as: criterion A: IOP <15 mmHg for moderate glaucoma or <12 mmHg for severe glaucoma with or without AGMs OR criterion B: reduction in number of AGMs by >1.

RESULTS

Thirty-two eyes of 32 patients underwent BANG + phaco. Mean age of the participants was 62.7 ± 8.4 years and there were 25 males and seven females. At 12 months, a significant decrease was noted in both IOP (from 17.6 ± 3.6 to 12 ± 1.6 mmHg, 31.8%; P < 0.001) and AGMs (from 3.7 ± 0.9 to 2.8 ± 0.8, 24.3%; P < 0.001). Twenty percent or more reduction in IOP was achieved in 62.5% (20/32) of eyes. Overall success (meeting either of the criteria A or B) at 12 months was achieved in 87.5% eyes. Mild postoperative hyphema was noted in 10 (31.2%) eyes, and two eyes (6.2%) required additional filtration surgery at 7 months.

CONCLUSION

A 30-degree BANG with phaco in patients of POAG appears to be a safe, effective and affordable MIGS for developing countries.

Visual results and subjective satisfaction after implantation of two different trifocal diffractive intraocular lenses models (AcrySof IQ PanOptix and AT LISA tri 839 MP)

BACKGROUND

This study aimed to compare visual results following the implantation of two distinct diffractive trifocal IOLs utilizing various vision evaluation techniques and subjective satisfaction.

METHODS

The study included 32 eyes receiving AcrySof IQ PanOptix implantation and 32 receiving AT LISA tri 839 MP. Post-operative examination at one year included uncorrected visual acuity (UCVA), distance-corrected visual acuity (DCVA) at 4 m, 80 cm, 60 cm, and 40 cm, Contrast sensitivity under photopic and mesopic conditions, and a questionnaire on subjective quality of vision, optical phenomena, and spectacle independence.

RESULTS

The two groups were similar in baseline demographics, pre-operative visual, biometric data (except for axial length), and surgical paraments. The PanOptix outperformed the AT LISA tri in the intermediate range when using the standard visual acuity testing (UCVA: 0.23 ± 0.14 logMAR vs. 0.31 ± 0.17 logMAR, p = 0.04; BCVA: 0.21 ± 0.12 vs. 0.28 ± 0.14, p = 0.03) and in the intermediate and far range when using the interactive computer program (intermediate: UNVA "E" optotype test: 0.05 ± 0.12 vs. 0.12 ± 0.13, p = 0.03; Far: UNVA "E" optotype: 0.07 ± 0.12 vs. 0.13 ± 0.10, p = 0.05). In addition, the PanOptix group had higher contrast sensitivity under photopic and mesopic conditions with and without glare at all spatial frequencies. There was no difference in subjective outcomes between the groups.

CONCLUSIONS

Patients who received PanOptix IOL had better visual outcomes for intermediate and far with higher contrast sensitivity under various conditions. Based on patients ' needs and demands, these results could support discussion when tailoring the optimal multifocal IOl.

Narrative review after post-hoc trial analysis of factors that predict corneal endothelial cell loss after phacoemulsification: Tips for improving cataract surgery research

PURPOSE

Identifying pre/perioperative factors that predict corneal endothelial-cell loss (ECL) after phacoemulsification may reveal ways to reduce ECL. Our literature analysis showed that 37 studies have investigated one or several such factors but all have significant limitations. Therefore, the data of a large randomized controlled trial (PERCEPOLIS) were subjected to post-hoc multivariate analysis determining the ability of nine pre/perioperative variables to predict ECL.

METHODS

PERCEPOLIS was conducted in 2015-2016 to compare two phacoemulsification techniques (subluxation and divide-and-conquer) in terms of 3-month ECL. Non-inferiority between the techniques was found. In the present study, post-hoc univariate and multivariate analyses were conducted to determine associations between ECL and age, sex, cataract density, preoperative endothelial-cell density, phacoemulsification technique, effective phaco time (EPT), and 2-hour central-corneal thickness. The data are presented in the context of a narrative review of the literature.

RESULTS

Three-month data were available for 275 patients (94% of the randomized cohort; mean age, 74 years; 58% women). Mean LOCSIII cataract grade was 3.2. Mean EPT was 6 seconds. Mean ECL was 13%. Only an older age (beta = 0.2%, p = 0.049) and higher EPT (beta = 1.2%, p = 0.0002) predicted 3-month ECL. Cataract density was significant on univariate (p = 0.04) but not multivariate analysis. The other variables did not associate with ECL.

CONCLUSIONS

Older age may amplify ECL due to increased endothelial cell fragility. EPT may promote ECL via cataract density-dependent and -independent mechanisms that should be considered in future phacoemulsification research aiming to reduce ECL. Our literature analysis showed that the average ECL for relatively unselected consecutively-sampled cohorts is 12%.

Risk factors for a phacodonesis surprise during cataract surgery in patients with pseudoexfoliation

PURPOSE

To evaluate the association of different pre-operative parameters with surprise phacodonesis during cataract surgery among patients with pseudoexfoliation (PXF).

MATERIALS AND METHODS

This is a retrospective charts review of all PXF patients who underwent cataract surgery between the years 2013 and 2018. Pre-operative parameters (demographics, biometry, intraocular pressure (IOP), endothelial cell count, pupil size, cataract density, glaucoma status, cup to disc ratio, number of glaucoma medications, prior intra-vitreous injections, risk for intraoperative floppy iris syndrome) were compared between patients with and without surprise phacodonesis. Binary logistic regression was used to calculate the predictive value of each parameter.

RESULTS

Out of 396 surgical cases with computerized pre-operative assessment, we included 127 eyes of 120 PXF patients without evidence of phacodonesis preoperatively. The mean age was 77.8 ± 12.0 years, 63 (52.7%) were male, and 106 (84.2%) underwent phacoemulsification surgery. We identified 10 cases of surprise phacodonesis during surgery (8.2%). Compared to PXF cases without intraoperative phacodonesis, they had higher pre-operative IOP (23.0 ± 11.0 mmHg vs. 14.9 ± 3.8 mmHg, p < 0.001) and a higher rate of B scan use due to dense cataract obscuring posterior pole evaluation [4 (40%) vs. 15 (12.8%), p = 0.04]. Multivariant binary logistic regression confirmed that only baseline IOP contributed to the prediction of surprise phacodonesis (OR 1.22 CI 1.04-1.43, p = 0.014).

CONCLUSIONS

Among patients with PXF undergoing cataract surgery, elevated IOP and poor posterior segment visibility requiring B scan use were associated with zonular instability putting these patients at risk for intra-operative complications.

The human lens is capable of trilineage differentiation towards osteo-, chondro-, and adipogenesis-a model for studying cataract pathogenesis

The potential for trilineage differentiation of cells in tissues represents a model for studying disease pathogenesis and regeneration pathways. Human lens trilineage differentiation has not yet been demonstrated, and so has calcification and osteogenic differentiation of human lens epithelial cells in the whole human lens. Such changes can pose a risk for complications during cataract surgery. Human lens capsules (n = 9) from cataract patients undergoing uneventful surgery were trilineage-differentiated toward osteogenesis, chondrogenesis, and adipogenesis. Furthermore, whole human healthy lenses (n = 3) collected from cadaveric eyes were differentiated into bone and characterized by immunohistochemistry. The cells in the human lens capsules were capable of undergoing trilineage differentiation, while the whole human healthy lenses could undergo osteogenesis differentiation, expressing osteocalcin, collagen I, and pigment epithelium-derived factor. We, hereby, show an ex vivo model for cataract formation through different stages of opacification, as well as provide in vivo evidence from patients undergoing calcified lens extraction with bone-like consistency.

In situ assessment of lens elasticity with noncontact optical coherence elastography

Lens biomechanics has great potential for application in clinical diagnostics and treatment monitoring of presbyopia and cataracts. However, current approaches to lens elastography do not meet the desired safety or sensitivity for clinical application. In this regard, we propose a noncontact optical coherence elastography (OCE) method to facilitate quantitative in situ imaging of lens elasticity. Elastic waves induced by air-pulse stimulation on the limbus propagate to the lens and are then imaged using custom-built swept-source optical coherence tomography to obtain the elastic wave velocity and Young's modulus. The proposed OCE method was first validated by comparing the results of in situ and in vitro measurements of porcine lenses. The results demonstrate that the Young's modulus measured in situ was highly consistent with that measured in vitro and had an intraclass correlation coefficient of 0.988. We further investigated the elastic changes induced by cold storage and microwave heating. During 36-hour cold storage, the mean Young's modulus gradually increased (from 5.62 ± 1.24 kPa to 11.40 ± 2.68 kPa, P < 0.0001, n = 9) along with the formation of nuclear opacities. 15-second microwave heating caused a greater increase in the mean Young's modulus (from 6.86 ± 1.21 kPa to 25.96 ± 8.64 kPa, P < 0.0025, n = 6) without apparent cataract formation. Accordingly, this study reports the first air-pulse OCE measurements of in situ lenses, which quantified the loss of lens elasticity during simulated cataract development with good repeatability and sensitivity, thus enhancing the potential for adoption of lens biomechanics in the clinic.

Correction of pre-existing astigmatism by on-axis incision size modulation in manual small-incision cataract surgery

Purpose

To study the effect of wound size modulation on pre-existing astigmatism by on-axis placement of incision in manual small-incision cataract surgery (MSICS).

Methods

In this prospective interventional study conducted at a tertiary care centre, 40 eyes of 40 consecutive senile cataract patients with 1.00-3.00 D corneal astigmatism were enrolled for the study. MSICS by modified Blumenthal's technique was performed through 6.0, 6.5, and 7.0 mm on-axis incision in 1.0-1.49 D (group A), 1.50-1.99 D (group B), and 2.00-3.00 D (group C) astigmatism, respectively. Surgically induced astigmatism (SIA) was calculated by vector analysis and double angle plots (DAP) at 12 weeks postoperatively.

Results

There were 22 males and 18 females with mean age of 58.12 ± 1.18 years. The mean SIA at 12 weeks was 0.85 ± 0.28 D in group A (17 eyes), 1.32 ± 0.65 D in group B (10 eyes), and 1.91 ± 0.69 D in group C (13 eyes). The overall median uncorrected visual acuity was 0.18 (IQR = 0 to 0.2). The mean astigmatism decreased from 1.95 ± 0.74 D to 1.04 + 0.57 D (P = 0.00) in superior incision and from 1.70 + 0.50 D to 0.92 ± 0.45 D (P = 0.00) in temporal incision group with central shift of centroid in all cases.

Conclusion

The customization of on-axis external incision size can be used to manage pre-existing corneal astigmatism of less than 3.00 D using both temporal and superior incisions effectively.

Use of Black-and-White Digital Filters to Optimize Visualization in Cataract Surgery

PURPOSE

To evaluate the effect of a black-and-white (BW) filter on the optimization of visualization at each stage of cataract surgery.

METHODS

Prospective, single-center, single-surgeon, consecutive case series of 40 patients undergoing cataract surgery with BW filter. Surgical images and videos were recorded with and without the BW filter at each stage of cataract surgery. Contrast measurements of surgical images and subjective analysis of video sequences were performed.

RESULTS

The surgeons assessed the BW filter to optimize the tissue visibility of capsulorhexis contours, hydrodissection fluid wave perception, the contrast of instruments through a nucleus during phaco-chop, and subincisional cortex contrast through the corneal edema. Despite the higher contrasts' value obtained with BW filter images during nucleus removal, posterior capsular polishing and viscous removal, the surgeons subjectively reported no significant advantage of using a BW filter. Standard color images were found to be better for localizing the limbal area during incision and for nucleus sculpture to assess groove depth.

CONCLUSIONS

In conclusion, we describe here the potential indications for BW filter use at particular stages in cataract surgery. A BW filter could be used, with caution, in cases of poor visualization.

Advancements in Postoperative Care after Cataract Surgery

Cataract surgery is one of the most frequently performed surgical procedures in many countries [...].

Facilitating Role of the 3D Viewing System in Tilted Microscope Positions for Cataract Surgery in Patients Unable to Lie Flat

PURPOSE

To assess the utility of the 3D viewing system in tilted microscope positions for the performance of cataract surgery in challenging positions, for patients with difficulty remaining supine.

METHODS

Prospective, single-center, single-surgeon, consecutive case series of patients undergoing surgery in an inclined position.

RESULTS

21 eyes of 15 patients who had undergone surgery at inclined positions at angles of 20° to 80°, with a mean angle of 47.62°. Surgeon comfort was considered to be globally good. The surgeon rated red reflex perception and the impression of depth as good and stable in all cases. The operating time was slightly longer for patients inclined at angles of more than 50°. On the first day after surgery, BSCVA was 20/25 or better in all cases. No ocular complications occurred in any of the interventions.

CONCLUSIONS

Due to the ocular-free design of the 3D system, the surgical procedure and the positioning of the surgeon remained almost identical to that for patients undergoing surgery in a supine position, maintaining the safety of the standard surgical approach.

Correlation Between Degree of Lens Opacity and the Phacoemulsification Energy Parameters Using Different Imaging Methods in Age-Related Cataract

Purpose

To compare the correlation between degree of lens opacity and the phacoemulsification energy parameter in patients with age-related cataract as determined by slit lamp, 25-MHz ultrasound biomicroscopy (UBM), and Scheimpflug imaging (Pentacam) and to evaluate the application of these three methods to measuring lens opacification.

Methods

This observational study was conducted in 319 patients (381 eyes) with different types of age-related cataract. The average age of patients was 67.3 ± 11.4 years. The degree of lens opacity acquired by slit lamp, 25-MHz UBM, and Pentacam was determined by the Lens Opacity Classification System III (LOCSIII), pixel units calculated by ImageJ, and lens density, respectively. We primarily analyzed and compared the correlation between lens opacity and the cumulative dissipated energy (CDE) values of phacoemulsification.

Results

Cortical, nuclear, and posterior subcapsular (PSC) cataracts were evaluated as follows: LOCSIII grades 3.31 ± 1.42, 3.29 ± 1.49, and 0.91 ± 0.83; pixel units 120.91 ± 22.8, 93.2 ± 15.9, and 99.7 ± 13.0; and lens density 51.8 ± 31.2, 21.2 ± 6.10, and 53.3 ± 35.3, respectively. The CDE values were 12.1 ± 12.4, 13.5 ± 9.11, and 3.93 ± 1.96. In cortical cataract, there was a linear correlation among LOCSIII, pixel units, and CDE value (r = 0.560, r = 0.832, and r = 0.582, respectively; both P < 0.05), but lens density had no correlation with other parameters. In nuclear cataract, there was a linear correlation among LOCSIII, lens density, and CDE value (r = 0.747, r = 0.865, and r = 0.906, respectively; both P < 0.05), but pixel units had no correlation with other parameters. In PSC, only pixel units and LOCSIII showed a correlation.

Conclusions

The various imaging methods offered different advantages in terms of determining lens opacity, a feature related to types of age-related cataracts. Choosing the most suitable imaging method to evaluate lens opacification based on the type of age-related cataract is important for accurately predicting the phacoemulsification parameters for cataract surgery.

Translational Relevance

Determining the appropriate phacoemulsification strategy depends on quantitative analysis of the degree of lens opacity to reduce intraoperative and postoperative complications and to obtain the optimal postoperative visual outcome.

Early corneal pachymetry maps after cataract surgery and influence of 3D digital visualization system in minimizing corneal oedema

PURPOSE

To describe the early topography of corneal swelling occurring after cataract surgery and to evaluate the impact of the three-dimensional (3D) digital visualization system in minimizing corneal oedema.

METHODS

Prospective observational, single-centre, consecutive case series of 134 patients undergoing cataract surgery performed by the same surgeon, with either 3D or conventional visualization systems. Eyes were assigned to two groups based on their anterior chamber depth (group ACD ≤3 mm and group ACD >3 mm). Optical coherence tomography was performed to evaluate postoperative corneal swelling.

RESULTS

Three corneal swelling profiles were identified on the first postoperative day type 1, limited corneal oedema near peripheral corneal incisions; type 2, dome-shaped corneal swelling spreading from the principal corneal incision and reaching the paracentral cornea; type 3, continuous oedema spreading from the principal incision to central cornea, with a generalized oedema predominating in the upper part of the cornea. On the first day after surgery, in group ACD ≤3 mm, visual acuity was significantly better in patients undergoing surgery with 3D visualization (0.023 vs 0.072 logMar, p = 0.014) with reduced central corneal thickening 17.3 µm (±3.2) in comparison with conventional visualization 44.0 µm (±9.3) (p = 0.0082). In group ACD >3 mm, no significant association was found between the use of the 3D system and pachymetry changes and early visual rehabilitation. On day 21 after surgery, no significant differences in corneal pachymetry values were observed between the two surgical approaches in both groups.

CONCLUSIONS

We describe early postoperative corneal map profiles providing insight into the pathogenesis of postoperative corneal swelling and possible prevention strategies. By improving visualization of the narrow surgical space in patients with shallow anterior chambers, the 3D system could help to minimize postoperative corneal oedema.