Validation of the Nuclear Cataract Grading System BCN 10

AOP report: Development of an adverse outcome pathway for deposition of energy leading to cataracts

Cataracts are one of the leading causes of blindness, with an estimated 95 million people affected worldwide. A hallmark of cataract development is lens opacification, typically associated not only with aging but also radiation exposure as encountered by interventional radiologists and astronauts during the long-term space mission. To better understand radiation-induced cataracts, the adverse outcome pathway (AOP) framework was used to structure and evaluate knowledge across biological levels of organization (e.g., macromolecular, cell, tissue, organ, organism and population). AOPs identify a sequence of key events (KEs) causally connected by key event relationships (KERs) beginning with a molecular initiating event to an adverse outcome (AO) of relevance to regulatory decision-making. To construct the cataract AO and retrieve evidence to support it, a scoping review methodology was used to filter, screen, and review studies based on the modified Bradford Hill criteria. Eight KEs were identified that were moderately supported by empirical evidence (e.g., dose-, time-, incidence-concordance) across the adjacent (directly linked) relationships using well-established endpoints. Over half of the evidence to justify the KER linkages was derived from the evidence stream of biological plausibility. Early KEs of oxidative stress and protein modifications had strong linkages to downstream KEs and could be the focus of countermeasure development. Several identified knowledge gaps and inconsistencies related to the quantitative understanding of KERs which could be the basis of future research, most notably directed to experiments in the range of low or moderate doses and dose-rates, relevant to radiation workers and other occupational exposures.

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.

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.

Clinical Practice of Cataract Special Care Standards in Nonophthalmic Wards

Cataract is a lens metabolism disease, which is caused by various factors, and leads to metamorphic lens proteins turbidity. Cataract commonly occurs in elderly patients, and majority of these patients have clinical manifestations of blurred vision and other symptoms. In this study, we explored the clinical practice and observations of cataract care criteria in nonophthalmic wards. To realize this, a total of one hundred and twenty (120) cataract patients, admitted to the East Department of Ophthalmology, Shanghai Sixth People's Hospital, particularly from April 2019-2020, were divided into the control and observation groups, where 60 cases were added to each group. The control group received routine nursing, and observation group was treated with cataract care criteria based on the control group. The complication rate, health cognition, and patient's satisfaction were compared with existing approaches. The incidence of corneal edema, anterior chamber hemorrhage, endophthalmitis, and incision infection, specifically in the observation group, was lower than that in the control group (P < 0.05). Likewise, the number of hospitalization days and expenses, specifically in the observation group, were lower than those in the control group (P < 0.05). Health knowledge and satisfaction scores of the observation group were higher than the control group (P < 0.05). Active service, service attitude, psychological support, caring patients, and health education dissatisfaction rate of the observation group were lower than the control group (P < 0.05). Finally, the standard of cataract care in nonophthalmic wards reduces the incidence of complications, improve health awareness of patients, and help to improve satisfaction of patients with nurses. Furthermore, it is worthy of promotion and application particularly in traditional hospitals.

Difluprednate 0.05% twice a day vs Prednisolone acetate 1% four times a day for cataract postsurgical inflammation treatment: a non-inferiority trial

PURPOSE

To establish if Difluprednate 0.05% nanoemulsion (DIFL) twice a day (BID) is as effective as Prednisolone acetate 1% + Phenylephrine hydrochloride 0.12% suspension (PRED) four times a day (QID) on postsurgical inflammation treatment.

SETTING

4 private Argentine ophthalmological centers.

DESIGN

Non-inferiority, prospective, multicenter, double-blind, randomized, parallel-group, comparative trial.

METHODS

A total of 259 patients who underwent phacoemulsification randomly received DIFL or PRED starting the day before surgery and continuing for 28 days. The primary endpoint was central corneal thickness. Non-inferior anti-inflammatory efficacy was considered if the difference of corneal thickness between baseline and Day 4 did not differ beyond 17 µm between treatments. Secondary endpoints were cell & flare, corrected distance visual acuity (CDVA), endothelial cell count, OCT-central macular thickness, and intraocular pressure (IOP). All outcomes were evaluated at baseline, day 1, 4, and 28 after surgery.

RESULTS

225 patients finished the study. The difference in corneal thickness at baseline and Day 4 did not differ beyond 17 µm between treatments (IC95% -2.78µm - 14,84 µm), with no statistically significant difference between treatments (p = 0.523). There were not statistically significant differences between groups on total anterior chamber clearance at any study time (p > 0.05). No statistically significant differences were reported between treatments in CDVA (p = 0.455), endothelial cell count (p = 0.811), OCT-central macular thickness (p = 0.869), and in intraocular pressure outcome (p = 0.316).

CONCLUSIONS

Difluprednate administered BID is at least as effective as Prednisolone acetate administered QID on inflammatory treatment following cataract surgery.

Development of a valid and reliable pterygium surgery assessment scale for ophthalmology residents

BACKGROUND

Microsurgery training has become an important part of ophthalmology teaching and one of the main topics of examination. Accurate and effective evaluation of microsurgery skills is vital for the training and teaching of residents. In this study, we aimed to establish a pterygium surgery assessment scale for use by ophthalmic residents and evaluate its reliability and validity.

METHODS

Based on a literature search, experienced pterygium surgeons developed the preliminary scale according to the standard surgical procedure. The preliminary scale and a questionnaire were sent to teaching and research experts in the field for feedback. Face and content validity and reliability of the scale were determined by rounds of modifications based on expert feedback. For construct validity, existing assessment scales were obtained and a range of factors were tested.

RESULTS

Nineteen expert surgeons completed the questionnaire and modifications were made until all surgeons agreed on the final scale. Good construct validity was found by evaluation against 257 existing scales. For reliability, 280 evaluation scales were completed. Inter- and intra-rater reliability analysis both found Intraclass Correlation Coefficient (ICC) > 0.8 for all items and total scores.

CONCLUSION

The pterygium surgery assessment scale developed in this study has good reliability and validity, and is an effective measurement tool for the evaluation of ophthalmology residents' pterygium surgical skills.

Deformations and Ruptures in Human Lenses With Cortical Cataract Subjected to Ex Vivo Simulated Accommodation

Purpose

Human cortical opacities are most commonly accompanied by changes in lens fiber structure in the equatorial region at the lens nucleus–cortex interface. Cortex and nucleus have different elastic properties, which change with age. We therefore subjected ex vivo lenses to simulated accommodation and studied the internal deformations to better understand the mechanism of cortical cataract formation.

Methods

Nine human donor lenses (33–88 years old) were tested using a bespoke radial stretching device for anterior eye segments. Seven of the lenses exhibited cortical cataracts. The other two lenses, without cataract, were used as controls. Frontal and cross-sectional images of the lens obtained during stretching facilitated measurements on equatorial lens diameter and central lens thickness in the stretched and unstretched states.

Results

Stretching caused the lens equatorial diameter to increase in all cases. Conversely, the lens central thickness showed no systematic variation during stretching. For four of the lenses with cortical cataract, ruptures were observed during stretching at the nucleus–cortex boundary adjacent to the cortical cataracts. Ruptures were not observed in the control lenses or in the three other lenses with cortical cataract.

Conclusions

Internal ruptures can occur in aged ex vivo lenses subjected to simulated disaccommodation. These ruptures occur at the nucleus–cortex interface; at this location, a significant stiffness discontinuity is expected to develop with age. It is hypothesized that ruptures occur in in vivo lenses during accommodation—or attempted accommodation.

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

Background: The aim of this study was to evaluate whether a simplified pre-operative nuclear classification score (SPONCS) was valid, both for clinical trials and real-world settings. Methods: Cataract classification was based on posterior nuclear color: 0 (clear), 1 (subcapsular/posterior cataract with clear nucleus), 2 (mild “green nucleus” with plus sign for yellow reflection of the posterior cortex), 3 (medium “yellow nucleus” with plus sign for brown/red posterior cortex reflection), 4 (advanced with 4 being “red/brown nucleus” and 4+ white nucleus), and 5 (hypermature/Morgagnian nucleus). Inter- and intra-observer validity was assessed by 30 Ophthalmologists for 15 cataract cases. The reliability of the cataract grading score in a surgical setting was evaluated. Correlation of nuclear scores was compared with phacoemulsification cumulative dissipated energy (CDE) in 596 patients. Results: Analysis of mean intra-observer Cohen kappa agreement was 0.55 with an inter-observer score of 0.54 for the first assessment and 0.49 for the repeat assessment one week later. When evaluating results by nuclear color alone, there was a substantial agreement for both the intra-observer (0.70) and inter-observer parameters: 0.70 for the first test, and 0.66 on repetition with randomization of the cases after a week. CDE levels were found to be significantly different between all SPONCS score groups (p < 0.001), with a lower CDE related to a lower SPONCS score. A strong correlation was found between the SPONCS score and CDE (Spearman′s rho = 0.8, p < 0.001). Conclusion: This method of grading cataract hardness is both simple and repeatable. This system can be easily incorporated in randomized controlled trials to lower bias and confounding effects regarding nuclear density along with application in the clinical setting.

Pre-operative simulation of post-operative multifocal vision

While multifocal intraocular lenses (MIOLs) are increasingly implanted to correct for presbyopia, how one sees with a multifocal correction is hard to explain and imagine. The current study evaluates the quality of various visual simulating technologies by comparing vision with simulated MIOLs pre-operatively and the implanted MIOLs post-operatively in the same patients. Two simulation platforms were used: (1) a custom-developed adaptiveoptics (AO) system, with two visual simulator devices: a spatial light modulator (SLM) and an optotunable lens operating under temporal multiplexing (SimVis); and (2) a wearable, binocular, large field of view SimVis2Eyes clinical simulator (SimVis Gekko, 2Eyes Vision, Madrid, Spain). All devices were programmed to simulate a trifocal diffractive MIOL (POD F, FineVision, PhysIOL). Eight patients were measured pre-operatively simulating the trifocal lens and post-operatively with implantation of the same MIOL. Through-focus decimal visual acuity (TF VA) was measured (1) monocularly in monochromatic light using a four-alternative-forced-choice procedure in the AO system; and (2) binocularly using a clinical optotype in white light. Visual simulations pre-operatively predict well the TF VA performance found post-operatively in patients implanted with the real IOL. The average RMS difference between TF curves with the different visual simulators was 0.05 ± 0.01. The average RMS difference between the TF VA curves with the SimVis pre-operatively and the real MIOL post-operatively was 0.06 ± 0.01 in both platforms, and it was higher in cataract eyes (0.08 ± 0.01, on average across simulators) than in eyes with clear lens. In either group the shape of the TF curves is similar across simulators and pre- and post-operatively. TF curves cross-correlated significantly between simulators (lag k = 0, rho = 0.889), as well as with results with the real MIOL implanted (lag k = 0, rho = 0.853). Visual simulations are useful programmable tools to predict visual performance with MIOLs, both in an AO environment and in a clinical simulator. Pre-operative visual simulations and post-operative data are in good agreement.

Cortical Cataract and Refractive Error

PURPOSE

To evaluate the relationship between the presence of cortical cataract and accommodation effort, using refractive error as a proxy.

METHODS

Patients between 50 and 90 years, scheduled for cataract surgery, were selected with the help of a photographic database. Nuclear and cortical cataract were graded and patients grouped having no cataract, pure cortical, mixed or pure nuclear cataract. Refraction data at the time of the photograph was converted to estimated spherical equivalent refractive error each patient would have had at the age of 45 years.

RESULTS

From the initial 239 eyes from 239 patients, cases with myopia below -6.5 dpt and hyperopia above 6.5 dpt were excluded, resulting in 199 cases for final analysis. Eyes with no cataract showed the lowest median refractive error (-3.65 dpt), followed by the pure nuclear group (-2.69 dpt). The median refractive error for pure cortical (-0.23 dpt) and mixed cataracts (-0.87 dpt) were close to emmetropia. Cortical cataracts were found in 37% of myopes, 82% of emmetropes, and 85% of hyperopes.

CONCLUSION

Emmetropes and hyperopes tend to develop more cortical cataract than myopes. These cortical cataracts might be caused by shear stress inside the crystalline lens due to accommodation efforts at the time of onset of presbyopia.

Reproducibility of macular and optic nerve head vessel density measurements by swept-source optical coherence tomography angiography

PURPOSE

To assess the reproducibility of swept-source optical coherence tomography angiography (SS-OCTA) for macular and optic nerve head (ONH) vessel density (VD).

METHODS

Cross-sectional study using the Triton OCTA (Topcon, Tokyo, Japan), for VD (%) measurements in 40 eyes of 40 healthy subjects on two 6 × 6 mm scans of the macula and ONH across five subfields (central, superior, inferior, temporal, and nasal) at different segmentation levels: superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina, and choriocapillaris. Reproducibility values were summarized as intraclass correlation coefficients (ICCs) and coefficients of variations (CV).

RESULTS

ICCs for the macular VD measurements in the central zone were 0.874, 0.770, 0.575, 0.718 at the levels SCP, DCP, outer retina, and choriocapillaris, respectively, while worse ICCs were obtained for the parafoveal subfields (ICC ⩽ 0.589); CVs were 2.8%-6.7%. The reproducibility of the ONH superficial VD was ICC = 0.941 for the papillary region and was ICC = 0.499-0.853 for the peripapillary zone; CVs ranged from 4.8% to 17%. Peripapillary VD showed an ICC = 0.533-0.770 in the DCP layer, and 0.572-0.828 in the choriocapillaris. Lowest VD were obtained for the macular SCP and DCP (23% and 22%, respectively), in the foveal zone, while greatest VD were recorded in the nasal and temporal peripapillary subfields at the level of the choriocapillaris (both 68%).

CONCLUSIONS

The new SS-OCTA software served to quantify macular and ONH VD with a reproducibility that was good in the central zones (foveal and papillary, respectively) and moderate in the peripheral zones (parafoveal and peripapillary).

Consensus on the management of astigmatism in cataract surgery

This project was aimed at achieving consensus on the management of astigmatism during cataract surgery by ophthalmologists from Latin America using modified Delphi technique. Relevant peer-reviewed literature was identified, and 21 clinical research questions associated with the definition, classification, measurement, and treatment of astigmatism during cataract surgery were formulated. Twenty participants were divided into seven groups, and each group was assigned three questions to which they had to respond in written form, after thoroughly reviewing the literature. The assigned questions with corresponding responses by each group were discussed with other participants in round 4 – presentation of findings. The consensus was achieved if approval was obtained from at least 80% of participants. The present paper provides several agreements and recommendations for management of astigmatism during cataract surgery, which could potentially minimize the variability in practice patterns and help ophthalmologists adopt optimal practices for cataract patients with astigmatism and improve patient satisfaction.

Estimation of intraocular lens position from full crystalline lens geometry: towards a new generation of intraocular lens power calculation formulas

In a cataract surgery, the opacified crystalline lens is replaced by an artificial intraocular lens (IOL). To optimize the visual quality after surgery, the intraocular lens to be implanted must be selected preoperatively for every individual patient. Different generations of formulas have been proposed for selecting the intraocular lens dioptric power as a function of its estimated postoperative position. However, very few formulas include crystalline lens information, in most cases only one-dimensional. The present study proposes a new formula to preoperatively estimate the postoperative IOL position (ELP) based on information of the 3-dimensional full shape of the crystalline lens, obtained from quantitative eye anterior segment optical coherence tomography imaging. Real patients were measured before and after cataract surgery (IOL implantation). The IOL position and the postoperative refraction estimation errors were calculated by subtracting the preoperative estimations from the actual values measured after surgery. The proposed ELP formula produced lower estimation errors for both parameters -ELP and refraction- than the predictions obtained with standard state-of-the-art methods, and opens new avenues to the development of new generation IOL power calculation formulas that improve refractive and visual outcomes.

Development of a new valid and reliable microsurgical skill assessment scale for ophthalmology residents

Background

More and more concerns have been arisen about the ability of new medical graduates to meet the demands of today’s practice environment. In this study, we wanted to develop a valid, reliable and standardized assessment tool for evaluating the basic microsurgical skills of residents in a microsurgery laboratory, to get them well prepared before entering the surgical realm of ophthalmology.

Methods

Twenty-three experts who have teaching experience reviewed the assessment scale. Constructive comments were incorporated to ensure face and content validity. Twenty-one attendings from different specialties then graded eight corneal rupture suturing videos with the scale to investigate interrater reliability. Fourteen of them graded the same videos 3 months later to investigate intrarater reliability (repeatability).

Results

A total of 280 assessment scales were completed. All the ICC values of interrater reliability were greater than 0.8 with 75% data greater than 0.9 (range 0.860–0.976). All the ICC values of intrarater reliability (repeatability) were also greater than 0.8 with 63% data greater than 0.9 (range 0.833–0.954).

Conclusions

The assessment scale we developed is valid and reliable. This tool could be useful to ensure that junior residents achieve a certain level of microsurgical technique in a laboratory environment before training in the operation room. Hopefully, this tool will provide a structured template for other residency programs to assess their residents for basic microsurgical skills.