The Auckland Cataract Study: 2 year postoperative assessment of aspects of clinical, visual, corneal topographic and satisfaction outcomes

Application of artificial intelligence in cataract management: current and future directions

The rise of artificial intelligence (AI) has brought breakthroughs in many areas of medicine. In ophthalmology, AI has delivered robust results in the screening and detection of diabetic retinopathy, age-related macular degeneration, glaucoma, and retinopathy of prematurity. Cataract management is another field that can benefit from greater AI application. Cataract  is the leading cause of reversible visual impairment with a rising global clinical burden. Improved diagnosis, monitoring, and surgical management are necessary to address this challenge. In addition, patients in large developing countries often suffer from limited access to tertiary care, a problem further exacerbated by the ongoing COVID-19 pandemic. AI on the other hand, can help transform cataract management by improving automation, efficacy and overcoming geographical barriers. First, AI can be applied as a telediagnostic platform to screen and diagnose patients with cataract using slit-lamp and fundus photographs. This utilizes a deep-learning, convolutional neural network (CNN) to detect and classify referable cataracts appropriately. Second, some of the latest intraocular lens formulas have used AI to enhance prediction accuracy, achieving superior postoperative refractive results compared to traditional formulas. Third, AI can be used to augment cataract surgical skill training by identifying different phases of cataract surgery on video and to optimize operating theater workflows by accurately predicting the duration of surgical procedures. Fourth, some AI CNN models are able to effectively predict the progression of posterior capsule opacification and eventual need for YAG laser capsulotomy. These advances in AI could transform cataract management and enable delivery of efficient ophthalmic services. The key challenges include ethical management of data, ensuring data security and privacy, demonstrating clinically acceptable performance, improving the generalizability of AI models across heterogeneous populations, and improving the trust of end-users.

Preserving posterior capsular integrity in post-endothelial keratoplasty posterior capsular opacification

Endothelial keratoplasty (EK) with pseudophakia often presents with late-onset proliferative after-cataract with posterior capsule distension. We performed a modified technique of capsular bag lavage in 11 eyes with late-onset PCO after EK (4 cases: post-DSAEK, 7 cases: post-DMEK). Anterior capsular rim was separated from the underlying IOL optic using MVR blade. Circumferential relaxing radial nicks were made on the capsular rim to create space for the passage of irrigation-aspiration (IA) probes behind the IOL. Bimanual IA of the flocculent cortical material was performed without damaging the posterior capsule. Air was injected at end of surgery to ensure graft apposition. All cases gained 1-3 lines of Snellen’s acuity and no case developed graft failure, rejection, or endothelial decompensation. An intact posterior capsule is associated with better outcomes post a repeat graft, if required. Our technique helps avoid complications related to a disturbed anterior hyaloid phase and minimizes postoperative inflammation.

Vision Restoration: Cataract Surgery and Surgical Correction of Myopia, Hyperopia, and Presbyopia

Cataract surgery is one of the most common surgical procedures performed in the United States. The decision to remove a cataract is determined by the patient's ability to perform activities of daily living, such as reading, driving, and watching television. Cataract surgery also offers the potential of spectacle independence with a wide array of premium intraocular lens options. In addition, with the continuing advances in ophthalmology, patients now also have the option of selecting between traditional approaches and femtosecond laser-assisted procedures. Cataract surgery continues to be an effective and ever-improving procedure for vision restoration.

The effect of capsule tension ring on posterior capsule opacification: A meta-analysis

Background

Posterior capsule opacification is one of the most common complications after cataract surgery. Studies have suggested that the introduction of a capsule tension ring might play a critical role in the prevention of capsule opacification, yet quantitative evidence is still lacking. This work consists of a meta-analysis on available data in order to explore the influence of a capsule tension ring on posterior capsule opacification.

Methods

A comprehensive review of the literature on capsule tension ring and posterior capsule opacification was carried out using the Embase, Pubmed, Web of Science, and Cochrane electronic databases. The selected studies included randomized controlled trials, retrospective studies and prospective studies published before June 2020. The studies of interest were selected by two reviewers independently from the included studies. Odds ratios (ORs) and standardized mean differences (SMD) were used in order to assess the association. A fixed-effects model or a random-effects model was applied to combine data according to heterogeneities. Sensitivity analysis was used to assess the heterogeneity of the studies. Publication bias was estimated using the Egger test. Statistical analysis was performed using the stata15.1 software.

Results

The meta-analysis included in total 8 studies involving 379 cases and 333 controls. There was a statistically significant difference of Nd:YAG laser capsulotomy rate (OR=0.241, 95% CI: 0.145, 0.400 I²=42.1%) between the capsule tension ring group and the control group, indicating that the tension ring reduced the Nd:YAG laser capsulotomy rate. Further studies with continuous data also revealed that the use of capsule tension ring was associated with a lower posterior capsule opacification score (SMD = -1.402, 95% CI: -2.448, -0.355 I²=95.0%). The sensitivity analysis suggested that the result of the re-combined analysis did not change notably, indicating that the result was reliable and stable. Both pooled analysis showed no evidence of publication bias.

Conclusion

The findings of this meta-analysis confirmed that capsule tension ring might reduce capsule opacification. Further studies should be made to validate the result.

Budget impact analysis of lens material on the posterior capsule opacification (PCO) as a complication after the cataract surgery

Background

Over 300,000 cataract operations are performed in Poland every year, and the most common, late complication of cataract removal surgery is posterior capsule opacification (PCO). The risk of PCO depends on the lens material. Hydrophobic acrylic lenses cause PCO less frequently as lymphatic endothelial cells show lower affinity for the surface of the lens made of silicone. The objective of this study is to assess the economic impact of using hydrophobic acrylic lenses compared to using hydrophilic acrylic lenses for cataract treatment in the Polish inpatient and outpatient settings.

Methods

A budget impact analysis (BIA) compared the economic outcomes associated with using hydrophobic acrylic lenses versus using hydrophilic lenses for patients undergoing cataract surgery. The BIA predicted annual expenses in the following scenarios: performing Nd:YAG to treat PCO within 2 and 3 years after implantation of hydrophobic or hydrophilic acrylic lenses for different lens structure. Data used to assess the frequency of PCO was determined in systematic literature review. Costs of current and predicted interventions were estimated based on average data from 19 Polish hospitals. Prices of health services were taken from official public tariff lists.

Results

The use of a hydrophobic lens significantly limits the number of complications after cataract surgery relative to a hydrophilic lens. As hydrophobic lenses have a higher unit price their use increases the cost of treatment which currently is not reflected by adequate difference in price of the service. Total annual National Health Fund (NHF) expenses for 3-year follow-up model range from 139.1 million EUR to 143.1 million EUR depending on the lens structure, due to the cost of complications.

Conclusions

BIA indicates the possibility of introducing surcharge for the use of hydrophobic lenses, which could increase the frequency of their use and reduce the number of complications after cataract surgery. It was estimated that total NHF expenses reach the minimum value for the surcharge at the level of 9 EUR. The surcharge of 14 EUR is the maximum value that does not increase the initial NHF expenses.

Application of artificial intelligence in anterior segment ophthalmic diseases: diversity and standardization

Artificial intelligence (AI) based on machine learning (ML) and deep learning (DL) techniques has gained tremendous global interest in this era. Recent studies have demonstrated the potential of AI systems to provide improved capability in various tasks, especially in image recognition field. As an image-centric subspecialty, ophthalmology has become one of the frontiers of AI research. Trained on optical coherence tomography, slit-lamp images and even ordinary eye images, AI can achieve robust performance in the detection of glaucoma, corneal arcus and cataracts. Moreover, AI models based on other forms of data also performed satisfactorily. Nevertheless, several challenges with AI application in ophthalmology have also arisen, including standardization of data sets, validation and applicability of AI models, and ethical issues. In this review, we provided a summary of the state-of-the-art AI application in anterior segment ophthalmic diseases, potential challenges in clinical implementation and our prospects.

The Auckland Cataract Study II: Reducing Complications by Preoperative Risk Stratification and Case Allocation in a Teaching Hospital

PURPOSE

To assess the effect of preoperative risk stratification for phacoemulsification surgery on intraoperative complications in a teaching hospital.

DESIGN

Prospective cohort study.

METHODS

Prospective assessment of consecutive phacoemulsification cases (N = 500) enabled calculation of a risk score (M-score of 0-8) using a risk stratification system. M-scores of >3 were allocated to senior surgeons. All surgeries were performed in a public teaching hospital setting, Auckland, New Zealand, in early 2016. Postoperatively, data were reviewed for complications and corrected distance visual acuity (CDVA). Results were compared to a prospective study (N = 500, phase 1) performed prior to formal introduction of risk stratification.

RESULTS

Intraoperative complications increased with increasing M-scores (P = .044). Median M-score for complicated cases was higher (P = .022). Odds ratio (OR) for a complication increased 1.269 per unit increase in M-score (95% confidence interval [CI] 1.007-1.599, P = .043). Overall rate of any intraoperative complication was 5.0%. Intraoperative complication rates decreased from 8.4% to 5.0% (OR = 0.576, P = .043) comparing phase 1 and phase 2 (formal introduction of risk stratification). The severity of complications also reduced. A significant decrease in complications for M = 0 (ie, minimal risk cases) was also identified comparing the current study (3.1%) to phase 1 (7.2%), P = .034. There was no change in postoperative complication risks (OR 0.812, P = .434) or in mean postoperative CDVA (20/30, P = .484) comparing current with phase 1 outcomes.

CONCLUSION

A simple preoperative risk stratification system, based on standard patient information gathered at preoperative consultation, appears to reduce intraoperative complications and support safer surgical training by appropriate allocation of higher-risk cases.

The effect of single-piece hydrophobic acrylic intraocular lenses on the development of posterior capsule opacification

PURPOSE

To evaluate the long-term effect of a single-piece hydrophobic acrylic intraocular lens (IOL), AcrySof SN60AT (Alcon Laboratories, Fort Worth, Texas, USA), on the development of posterior capsule opacification (PCO) 5 years postoperatively.

DESIGN

Prospective, observational, consecutive, case series.

METHODS

setting: Iladevi Cataract and IOL Research Center, Ahmedabad, India.

STUDY POPULATION

Three hundred and ninety eyes with uncomplicated age-related cataract were included. Patients with diabetes mellitus, glaucoma, high myopia, pseudoexfoliation, traumatic cataract, subluxated cataract, previous ocular surgeries, and allergy to dilating drops were excluded. intervention procedures: Digital retroillumination photographic documentation was performed and analyzed for PCO using Evaluation of Posterior Capsule Opacification software. The scores and areas were calculated.

MAIN OUTCOME MEASURES

PCO development and the influence of the anterior capsule cover (total on and part on) on the IOL optic was studied within the capsulorrhexis margin and the central 3.0 mm optic area.

RESULTS

There was a significant increase in PCO up to 3 years. No significant change in PCO was observed between 3 and 5 years within the capsulorrhexis margin and central 3.0 mm optic area. In the total on group, within the capsulorrhexis margin, significantly lower scores and areas were observed when compared with part-on scores and areas.

CONCLUSION

The increase in PCO up to 3 years was significant. Stabilization in PCO was observed between 3 and 5 years with no difference at 5 years. There was a low incidence of PCO in eyes with total anterior capsule cover over the IOL optic.

Influence of capsular tension ring on posterior capsule opacification in myopic eyes

Purpose:

To determine the effect of a capsular tension ring (CTR) implantation in preventing posterior capsular opacification (PCO) after cataract surgery in patients with high myopia.

Materials and Methods:

In this prospective single-surgeon standardized-surgical-procedure fellow-eye comparison trial, 34 patients with high myopia had phacoemulsification surgery. Although one eye received an acrylic intraocular lens (IOL) and CTR, other eye received only an IOL as control. PCO, within the capsulorhexis overlap, was documented by standardized digital retroillumination images at least 2 years post-operatively, and the percentage area of PCO was scored (scale 0%-100%) using the POCOman software system. The PCO score and the incidence of neodymium-doped yttrium aluminum garnet (Nd: YAG) capsulotomy of groups, and correlations between PCO score and presence of CTR, age, phaco time, refraction, and axial length (AL) were determined.

Results:

The mean time interval from surgery to PCO measurement was 43.4 ± 11.2 months for the eyes with a CTR and 43.1 ± 11.6 months for the controls (P = 0.91). The PCO score of the eyes with a CTR was significantly lower than in the controls (5.9 ± 4.3 vs. 22.3 ± 12.2, respectively; P < 0.001). There were statistically insignificant correlations between PCO score and pre-operative refraction (r = 0.02; P = 0.90), AL (r = 0.03; P = 0.80), phaco time (r = 0.11; P = 0.53), and patient's age (r = 0.23; P = 0.55). No patient with a CTR had a Nd: YAG laser capsulotomy, but it was six in controls (P = 0.025).

Conclusions:

CTR implantation seems to be effective in reducing the PCO and Nd: YAG laser capsulotomy rates in high myopic eyes.

Outcomes of phacoemulsification in patients with chronic ocular graft-versus-host disease

PURPOSE

The purpose of this study was to evaluate the outcomes of phacoemulsification in patients with ocular graft-versus-host disease (GVHD).

METHODS

The occurrence of cataracts, cataract surgery, and its outcomes were analyzed in the medical records of 229 patients (458 eyes) with ocular GVHD. Outcome measures included pre- and postoperative corrected distance visual acuity (CDVA) and the rate of postoperative complications.

RESULTS

Of the 458 eyes evaluated, 58 were pseudophakic; from the 400 phakic eyes, 238 (59 %) presented with cataracts and 62 (26 %) underwent cataract surgery. Analysis of postoperative complications and visual outcomes at 1 month was performed in 51 eyes in which detailed surgical and immediate postoperative records were available. Preoperatively, the mean CDVA was 0.67 ± 0.57 LogMAR (Snellen 20/93), improving postoperatively to 0.17 ± 0.18 (Snellen 20/29) at 1 month (P < 0.0001), and to 0.13 ± 0.14 (Snellen 20/26) by the final follow-up visit (P < 0.0001). Postoperative complications included corneal epithelial defects (8 %), filamentary keratitis (6 %), worsening of corneal epitheliopathy (16 %), posterior capsular opacification (18 %), and cystoid macular edema (4 %). A corrected distance visual acuity of 20/30 or better was achieved in 87 % of the eyes; suboptimal CDVA improvement was attributable to severe ocular surface disease, pre-existing advanced glaucoma, and prior macular surgery.

CONCLUSIONS

Phacoemulsification in patients with chronic ocular GVHD is a safe and efficacious procedure resulting in significant visual improvement. Overall, postoperative adverse events responded well to timely management.

[Clinical practice variation in cataract surgery]

PURPOSE

Cataract surgery rates have dramatically increased in the last two decades. However, clinical practice variation in cataract surgery has not been thoroughly studied. The aim of this review is to analyze clinical practice variation, including the causes and consequences of this phenomenon. Then, its role in health care planning and health care quality is focused, emphasizing the importance of reducing it and providing several practical strategies to accomplish it.

RECENT FINDINGS

The latest researches are presented in this article. They identify the development and implementation of clinical practice guidelines as the best tool to standardize care processes.

CONCLUSION

Managing unwarranted or unwanted variation would improve quality of care and may lead to a significant saving in health care spending.

Comparison of posterior capsule opacification in rabbit eyes receiving different administrations of rapamycin

BACKGROUND

Posterior capsule opacification (PCO) is a common complication after cataract surgery. The purpose of this study was to determine the effects of three administering ways of rapamycin (RAPA) on the formation of PCO in rabbit eyes for 12 weeks.

METHODS

Eighty rabbits were divided into four groups, according to the different administrations of RAPA which they received. These were: (1) the control group, (2) the irrigation-treated group - 5 ng/ml intraoperative RAPA irrigation solution, (3) the eye-drop-treated group - 2 mg/ml RAPA eye drops, and (4) the IOL-treated group - RAPA-poly(lactic-co-glycolic) acid (PLGA) loaded on the surface of intraocular lens (IOLs) (RAPA-PLGA-IOLs). All right eyes were treated with lens extraction plus IOL implantation, receiving relative administrations of RAPA. RAPA concentrations in the aqueous humour were determined by high performance of liquid chromatography (HPLC). The anterior chamber (AC) response was observed through slit-lamp biomicroscopy. After 12 weeks, the degree of PCO was determined by clinical evaluation. The histological sections, immunohistochemistry expression of proliferating cell nuclear antigen (PCNA) in the lens capsule were conducted.

RESULTS

In the early period, AC response for both experimental and control eyes were similar. In the IOL-treated group, RAPA reached its peak at 25.68 ± 0.74 μg/ml on the 4th day, and it was detectable until 8 weeks afterwards. However, in the other groups, RAPA could not be detected all the time. Compared with other groups, in the IOL-treated group, PCO was greatly alleviated; only a few layers of the lens epithelial cells (LECs) and a little proliferative material around the posterior capsules, and a significantly weak expression of PCNA in the nuclei of LECs. By contrast, there was no significant statistical difference in eye-drop-treated or irrigation-treated eyes and control eyes respectively.

CONCLUSIONS

Intraocular RAPA-PLGA-IOL was a promising, effective, and safe administration to prevent PCO compared with other methods in the rabbit PCO model.

A new technique for Nd:YAG laser posterior capsulotomy

AIM

To investigate the effects of a new opening pattern in neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy on visual function.

METHODS

This technique was conducted along a circular pattern. The energy ranged between 0.8 and 1.2 mJ/pulse was consumed and mean total energy levels were 74±21 mJ (mean±standard deviation: SD, from 40 to 167) and laser shots aimed at 150 µm away behind a datum point and went along an imaginary line which extends 0.5 mm inside from optic margin and into the circular en bloc pattern. Vitreous stands were attached with fragment and then they were cut off by the laser after circular application. The circular fragment was completely separated from vitreous, and then this fragment was quickly sunk in intravitreal space.

RESULTS

The follow-up period ranges from at least a week to 40mo, making 15.8mo on average. The procedural outcome showed 96% (74 eyes out of the 77 eyes) enhancement in patients' visual acuity. Cystoid macular edema or retinal detachment was not observed in any of the patients during follow-up periods.

CONCLUSION

This new technique is expected to improve the weaknesses that the conventional procedures have by adding the process to cut off vitreous stands attached with the fragment by the laser to the circular application.

Patients' Short-term Satisfaction With Cataract Surgery and Long-Term Sustainability of Improved Visual-Related Quality of Life Over 3 Postoperative Years

PURPOSE

This study aimed to assess self-reported satisfaction following cataract surgery, and the sustainability of improved visual function and health-related quality of life in a cataract surgical cohort over 3 years post-phacoemulsification surgery.

DESIGN

A clinic-based cohort study.

METHODS

Cataract surgical patients were recruited and followed up annually after surgery. Logarithm of the minimum angle of resolution (LogMAR) visual acuity, visual function (using the VF-14 questionnaire), and health-related quality of life (using the Short-Form Health Survey [SF-36] questionnaire) were assessed preoperatively and at 1, 2, and 3 years postoperatively.

RESULTS

Of the 2029 patients recruited, 1924 (94.8%) had at least 1 postoperative visit, and 1229 (63.9%) had the 3-year follow-up examination performed. The mean age was 75.1 ± 6 years, and 54.1% were female. Of the 1229, 439 (35.7%) and 286 (23.3%) had completed the VF-14 and SF-36 questionnaires, respectively, at all 3 follow-up visits. The majority (92.1%) of patients reported being satisfied with the outcome of the surgery 6 months postoperatively. The overall VF-14 scores were significantly improved at the 12-month postoperative visits compared with preoperative scores (P < 0.01), independent of age and sex. The improved VF-14 mean scores were sustained for up to 3 years postoperatively. Health-related quality of life (SF-36 scores) showed no significant changes between preoperative and 1-, 2-, and 3-year postoperative examinations.

CONCLUSIONS

We documented the sustainability of improvement in visual function-related quality of life associated with cataract surgery over 3 postoperative years. Cataract surgery was not associated with improvement in health-related quality-of-life scores.

Extended long-term outcomes of cataract surgery

PURPOSE

 To longitudinally report the changes in visual acuity (VA) and subjective visual function, 10 years after cataract surgery.

METHODS

This population-based prospective study reviewed 335 patients (85% of survivors) who underwent cataract surgery during a 1-year period in 1997-98, 289 of whom were also re-examined. The patients underwent a routine eye examination and answered the same visual function questionnaire (VF-14), preoperatively, 4 months postoperatively, 5 years and 10 years after surgery.

RESULTS

Ten years after surgery, the best corrected VA (BCVA) of the operated eye had deteriorated to a median of 0.06 (logMAR) (Snellen acuity: 20/23) from 0.046 (logMAR) (20/22) postoperatively (p = 0.001). More than two-thirds of the patients had <0.1 logMAR units worsening of BCVA compared with postoperatively. Approximately half of the patients had no deterioration in subjective visual function, and 77% had 10 points decline or less. Twelve per cent of the patients (42/335) had a worsening of more than 30 points. Effect size was calculated for the VF-14 total score at all three occasions of follow-up after surgery and was largest approximately 4 months postoperatively. Long-time follow-up of 10 years shows still moderate effect size.

CONCLUSION

 These results confirm the effectiveness of cataract extraction, offering good long-term visual rehabilitation for the majority of the patients. The most common cause for large functional loss after 10 years is age-related macular degeneration.

Efficient generation of lens progenitor cells from cataract patient-specific induced pluripotent stem cells

The development of a technique to induce the transformation of somatic cells to a pluripotent state via the ectopic expression of defined transcription factors was a transformational event in the field of regenerative medicine. The development of this technique also impacted ophthalmology, as patient-specific induced pluripotent stemcells (iPSCs) may be useful resources for some ophthalmological diseases. The lens is a key refractive element in the eye that focuses images of the visual world onto the retina. To establish a new model for drug screening to treat lens diseases and investigating lens aging and development, we examined whether human lens epithelial cells (HLECs) could be induced into iPSCs and if lens-specific differentiation of these cells could be achieved under defined chemical conditions. We first efficiently reprogrammed HLECs from age-related cataract patients to iPSCs with OCT-4, SOX-2, and KLF-4. The resulting HLEC-derived iPS (HLE-iPS) colonies were indistinguishable from human ES cells with respect to morphology, gene expression, pluripotent marker expression and their ability to generate all embryonic germ-cell layers. Next, we performed a 3-step induction procedure: HLE-iPS cells were differentiated into large numbers of lens progenitor-like cells with defined factors (Noggin, BMP and FGF2), and we determined that these cells expressed lens-specific markers (PAX6, SOX2, SIX3, CRYAB, CRYAA, BFSP1, and MIP). In addition, HLE-iPS-derived lens cells exhibited reduced expression of epithelial mesenchymal transition (EMT) markers compared with human embryonic stem cells (hESCs) and fibroblast-derived iPSCs. Our study describes a highly efficient procedure for generating lens progenitor cells from cataract patient HLEC-derived iPSCs. These patient-derived pluripotent cells provide a valuable model for studying the developmental and molecular biological mechanisms that underlie cell determination in lens development and cataract pathophysiology.

Complications of cataract surgery

Modern cataract surgery is safe in more than 95 per cent of patients. In the small number of cases where a serious complication occurs, the most common is an intra-operative posterior capsular rupture. This can lead to vitreous loss or a dropped nucleus and can increase the risk of post-operative cystoid macular oedema or retinal detachment. Post-operatively, posterior capsular opacification is the most common complication and can be readily treated with a YAG capsulotomy. The most devastating complication is endophthalmitis, the rate of which is now significantly decreased through the use of intracameral antibiotics. As a clinician, the most important step is to assess the patient pre-operatively to predict higher risk individuals and to counsel them appropriately. In these patients, various pre- or intra-operative management steps can be taken in addition to routine phacoemulsification to optimise their visual outcome.

Interventions for preventing posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, however this may lead to other complications and laser treatment is not available in large parts of the developing world. Therefore, many studies try to find factors influencing the development of PCO.

OBJECTIVES

To summarise the effects of different interventions to inhibit PCO. These include modifications of surgical technique and intraocular lens (IOL) design, implantation of additional devices and pharmacological interventions.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS in March 2009 and reference lists of identified trial reports.

SELECTION CRITERIA

We included only prospective, randomised and controlled trials with a follow-up time of at least 12 months. Interventions included modifications in surgical technique explicitly to inhibit PCO, modifications in IOL design (material and geometry), implantation of additional devices and pharmacological therapy compared to each other, placebo or standard treatment.

DATA COLLECTION AND ANALYSIS

We extracted data and entered it into RevMan. We compared visual acuity data, PCO scores and YAG capsulotomy rates and performed a meta-analysis when possible.

MAIN RESULTS

Sixty six studies were included in the review. The review was divided into three parts. 1. Influence of IOL optic material on the development of PCO. There was no significant difference in PCO development between the different IOL materials (PMMA, hydrogel, hydrophobic acrylic, silicone) although hydrogel IOLs tend to have higher PCO scores and silicone IOLs lower PCO scores than the other materials. 2. Influence of IOL optic design on the development of PCO. There was a significantly lower PCO score (-8.65 (-10.72 to -6.59), scale 0 to 100) and YAG rate (0.19 (0.11 to 0.35)) in sharp edged than in round edged IOLs, however not between 1-piece and 3-piece IOLs. 3. Influence of surgical technique and drugs on the development of PCO. There was no significant difference between different types of intraoperative/postoperative anti-inflammatory treatment except for treatment with an immunotoxin (MDX-A) which led to a significantly lower PCO rate.

AUTHORS' CONCLUSIONS

Due to the highly significant difference between round and sharp edged IOL optics, IOLs with sharp (posterior) optic edges should be preferred. There is no clear difference between optic materials. The choice of postoperative anti-inflammatory treatment does not seem to influence PCO development.

Evaluating wavefront analysis application in intraocular lens placement

PURPOSE OF REVIEW

New advances in wavefront analysis offer an opportunity for greater refinement of cataract surgery. In this article, we critically review the recent advances in wavefront technology with specific attention to its application in customizing cataract surgery.

RECENT FINDINGS

Historically, wavefront analysis has been implemented in corneal refractive procedures. Expansion of this technology may soon allow surgeons to choose the most optically appropriate intraocular lens for a patient's individualized wavefront pattern, thus allowing for a 'custom-fitted' intraocular lens. The benefit of full correction of all higher-order aberrations measured by wavefront analysis remains controversial. Additionally, in certain subsets of patients with specific anterior chamber pathology, wavefront intraocular lenses may not be appropriate.

SUMMARY

The application of wavefront technology continues to expand the surgical options available to the practicing ophthalmologist. Significant advances have been made in our understanding of wavefront analysis and its usefulness in vision correction. Careful consideration of the optics of the whole eye must be considered when implementing wavefront analysis.

Involvement of PI3K/Akt pathway in TGF-beta2-mediated epithelial mesenchymal transition in human lens epithelial cells

BACKGROUND

Epithelial mesenchymal transition (EMT) of postoperative remnants of lens epithelial cells (LECs) can lead to posterior capsule opacification. This study was designed to determine the effect of signaling pathways that contribute to TGF-beta2-mediated EMT in human lens epithelial B-3 cells (HLEB-3 cells).

METHODS

The HLEB-3 cells were cultured and stimulated with TGF-beta2 at different concentrations for an indicated time. The effect of TGF-beta2 on cell cycle distribution was measured by flow cytometry. Western blot and immunofluorescence were used to analyze changes in connexin 43, fibronectin, desmin and integrin beta(1) protein expression associated with EMT in HLEB-3 cells. Activation of phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways was also detected by Western blot.

RESULTS

The cell cycle progression of HLEB-3 cells was limited, and the cells underwent morphological alteration after treatment with TGF-beta2. Stimulation of HLEB-3 cells with TGF-beta(2) suppressed connexin 43 protein expression, increased fibronectin, desmin and integrin beta1 protein expression. TGF-beta2 activated PI3K/Akt in a time-dependent manner, but not extracellular signal-regulated kinase and p38 MAPK. The activation of PI3K/Akt was necessary for the TGF-beta(2)-stimulated downregulation of connexin 43, which in turn was necessary for TGF-beta2-induced EMT in HLEB-3 cells.

CONCLUSIONS

TGF-beta(2) is a potent growth factor for LEC EMT. TGF-beta(2)-induced EMT in LECs is mediated by the downregulation of connexin 43, which is regulated through the PI3K/Akt pathway.

Post-operative capsular opacification: a review

Post-operative capsular opacification is a multifactorial physiological consequence of cataract surgery. Opacification involving the central posterior capsule has a significant impact on high and low contrast acuity and low contrast sensitivity. The assessment of Posterior Capsule Opacification (PCO) on cadaver eyes, experimental studies, culture models and in clinical studies has provided an understanding of its pathogenesis. The proliferation, migration and abnormal differentiation of residual lens epithelial cells and fibers in the capsular bag have been implicated in the pathogenesis of PCO. The incidence and severity of PCO correlates to the meticulous use of surgical techniques, IOL optic edge designs and IOL materials. This article summarizes the clinical studies with recommendations for retarding the development of central PCO. It discusses experiments with pharmacological agents broadly categorized as anti-inflammatory, immuno-modulating, antiproliferative, antiadhering, antitransdifferentiating agents for the prevention of PCO. These studies will remain critical for future endeavors undertaken for eradication of PCO.

Interventions for preventing posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, however, this may lead to other complications and laser treatment is not available in large parts of the developing world. Therefore, many studies try to find factors influencing the development of PCO.

OBJECTIVES

To summarise the effects of different interventions to inhibit PCO. These include modifications of surgical technique and intraocular lens (IOL) design, implantation of additional devices and pharmacological interventions.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS in January 2007 and reference lists of identified trial reports.

SELECTION CRITERIA

We included only prospective, randomised and controlled trials with a follow-up time of at least 12 months. Interventions included modifications in surgical technique explicitly to inhibit PCO, modifications in IOL design (material and geometry), implantation of additional devices, and pharmacological therapy, compared to each other, placebo or standard treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted and entered into Review Manager. Visual acuity data, PCO score and YAG capsulotomy rates were compared and a meta-analysis was performed when possible.

MAIN RESULTS

Fifty three studies were included in the review. The review was divided into three parts. (1) Influence of IOL optic material on the development of PCO. Compared to other materials, the meta-analysis of the included studies showed a significantly higher PCO score (overall effect: 12.39 (95% confidence interval: 9.82 to 14.95), scale 0 to 100) and YAG rate (odds ratio: 8.37 (3.74 to 20.36)) only in hydrogel IOLs. (2) Influence of IOL optic design on the development of PCO. There was a significantly lower PCO score (-8.65 (-10.72 to -6.59), scale 0 to 100) and YAG rate (0.19 (0.11 to 0.35)) in sharp edged than in round edged IOLs, however, not between 1-piece and 3-piece IOLs. (3) Influence of surgical technique and drugs on the development of PCO. There was no significant difference between different types of intra-/postoperative anti-inflammatory treatment except for treatment with an immunotoxin (MDX-A) leading to a significantly lower PCO rate.

AUTHORS' CONCLUSIONS

Due to the highly significant difference between round and sharp edge IOL optics, IOLs with sharp (posterior) optic edges should be preferred. There is no clear difference between optic materials, except for hydrogel IOLs, that showed more PCO than the other materials. The choice of postoperative anti-inflammatory treatment does not seem to influence PCO development.

Corneal topography parameters after superior clear corneal incision cataract surgery in arcus lipoides

PURPOSE

To compare changes in corneal topographic parameters after cataract surgery in eyes with different severities of arcus lipoides.

METHODS

Fourty eyes of 40 patients (23 women, 17 men, age 71.3+/-20.4 years, range 40 to 89 years) were studied prospectively in a consecutive, non-interventional, comparative series of cases. Eyes were classed in three groups (0 to 2) according to the assessed grade of arcus lipoides (none, <180 degrees, >180 degrees). Corneal topography (Tomey TMS-2) was performed preoperatively and at 1 and 10 days and 1 and 3 months following cataract surgery (superior 4.0 mm clear corneal incision, no suture). Keratometric astigmatism (Dcyl), surface regularity index (SRI), surface asymmetry index (SAI), and potential visual acuity (PVA) were evaluated for the different groups and time-points, using the Kruskal-Wallis, Wilcoxon, and Mann-Whitney statistical tests.

RESULTS

No significant preoperative difference was found in mean Dcyl, SRI, or PVA; preoperative SAI was lower in Group 1. Postoperatively Dcyl was increased at day 1 in Groups 1 and 2, and remained higher in Group 2 until month 1. At month 3 significant differences among Groups 0, 1, and 2 disappeared.

CONCLUSIONS

The 4.0 mm superior clear corneal incision is a safe method for cataract surgery in the presence of arcus lipoides. This procedure induces greater corneal astigmatism, surface irregularity, and lower PVA in the early postoperative period in cases with arcus lipoides than in normal corneas. Concerning final results, wound healing was not affected by greater severity of arcus lipoides, although stabilization of the corneal surface tended to be slower.

Refractive expectations of patients having cataract surgery

PURPOSE

To assess the refractive expectations of patients having elective cataract surgery.

SETTING

Queen's Medical Centre, Nottingham, King's Mill Hospital, Sutton-in-Ashfield, and Kidderminster District Hospital, United Kingdom.

METHODS

A prospective questionnaire study of patients attending a preoperative assessment clinic for elective cataract surgery was performed. Only first-eye cataract surgery patients were included. Patients were excluded if they had visually impairing ocular comorbidity or if they were mentally unable to complete the questionnaire.

RESULTS

One hundred eighty-nine questionnaires were received. Mean patient age was 74 years (range 41 to 97 years). Sixty-four percent of respondents were women, and 90% were retired. On 10-point Likert scales (0 lowest, 10 highest), median patient scores for the perceived likelihood of needing spectacles after surgery were 8 for both distance and near correction. Patients already wearing distance correction thought it significantly more likely that they would need distance glasses postoperatively than those who did not (median likelihood scores 9 and 1, respectively; P<.0001). Similar differences in expectations were demonstrated for near correction. Median score of the importance of not needing spectacles was 8 for both distance and near. Men scored this higher than women, but only for distance. There was a weak negative correlation between the importance of spectacle independence and patient age.

CONCLUSIONS

Patients who already wear spectacles expect to need them after cataract surgery. Those not already wearing spectacles do not expect to need them. This latter group is at particular risk for refractive disappointment and complaint. In general, patients consider the opportunity to be free of glasses as very important.

Age-related maculopathy and cataract surgery outcomes: visual acuity and health-related quality of life

PURPOSE

To assess visual acuity (VA) and health-related quality of life (HRQoL) outcomes in patients with and without age-related maculopathy (ARM) after cataract surgery.

METHODS

Patients aged 60+ years who had undergone cataract surgery at the Westmead Hospital during 2001-2003 were re-examined 1-3 years after surgery. Tests included VA and assessment of visual- and HRQoL using standardised questionnaires (VF-14, SF-12). Preoperative comorbidity data were collected from medical records. Poor surgical outcomes (VA<6/12; no VA improvement; lowest quintile of VF-14, SF-12 scores) were compared in patients with and without ARM, adjusting for age, sex, preoperative systemic comorbidities, ocular comorbidities and surgical or postoperative complications.

RESULTS

Of 622 surviving patients, 454 (73%) were followed up for a mean period of 2.8 years. Similar proportions with VA>or=6/12 were observed in patients with (80.2%) and without (88.8%) pre-existing ARM. Preoperative early ARM was only associated with slightly lower mean VF-14 scores (87.64 with vs 92.58 without ARM, P=0.01). Increasing age and preoperative ocular comorbidities were associated with all poor outcomes measured. Low SF-12 scores were associated with preoperative systemic comorbidities.

CONCLUSION

Our study documents favourable cataract surgical outcomes 1-3 years after cataract surgery in patients with preoperative ARM.

Orbscan computerized topography: Attributes, applications, and limitations

An extensive electronic search was undertaken in January 2004 to identify all relevant peer-reviewed publications on Orbscan slit-scanning/Placido computerized topography. Ninety-one publications were identified. These address elevation topography and best-fit sphere, accuracy and repeatability of anterior and posterior corneal elevation and keratometric maps, comparison of Orbscan-acquired data and Placido-based computerized videokeratography instruments, pachymetry measurement and correlation with ultrasound, screening eye-bank corneas, detection of keratoconus, identifying corneal ectasia after refractive surgery, and miscellaneous applications. Studies were analyzed and critically compared in relation to attributes, applications, and limitations of Orbscan corneal topography. The review highlights advantages of this technique in assessing the cornea in health and disease and after surgery and identifies specific aspects that require further investigation and clarification.