Cataract progression after Nd:YAG laser iridotomy in primary angle-closure suspect eyes. Br J Ophthalmol 2022;Abstract.
BACKGROUND/AIMS: Prophylactic laser peripheral iridotomy (LPI) is performed in primary angle-closure suspect (PACS) eyes to prevent acute angle-closure attacks. However, accelerated cataractogenesis is a potential risk of the procedure that may result in decreased visual acuity. We aimed to assess the long-term impact of LPI on cataract formation in Chinese PACS. METHODS: In the Zhongshan Angle Closure Prevention Trial, eligible bilateral PACS participants received LPI in one randomly selected eye, while the fellow eye remained untreated. Cataract was graded using the Lens Opacity Classification System III, and progression was defined as an increase in grade by at least two units in any category or cataract surgery. RESULTS: In total, 889 participants were randomly assigned to LPI in one eye only (mean age 59±5 years, 83% female). At 72 months, treated eyes had slightly higher average nuclear grades (p<0.001). However, there were no differences between eyes for predefined cataract progression (cumulative probability at 72 months: 21.2% in LPI vs 19.4% in control, p=0.401) or cataract surgery (1% for both). While LPI-treated eyes had a 10% higher risk of progression over 6 years (HR=1.10 (95% CI 0.88 to 1.36)), this was not statistically significant. Visual acuity at 72 months was similar in treated and untreated eyes (p=0.43). CONCLUSION: Although lenses were graded on average as slightly more opaque in laser-treated eyes, prophylactic neodymium:yttrium-aluminum-garnet LPI did not cause significant cataract progression. Our results suggest that LPI treatment of asymptomatic narrow angles does not increase the risk of developing clinically meaningful cataract worsening over time. TRIAL REGISTRATION NUMBER: ISRCTN45213099.
Deviations from age-adjusted normative biometry measures in children undergoing cataract surgery: implications for post-operative target refraction and IOL power selection. Am J Ophthalmol 2022;Abstract.
PURPOSE: To evaluate whether pediatric eyes that deviate from age-adjusted normative biometry parameters predict variation in myopic shift after cataract surgery. METHODS: This is a single institution longitudinal cohort study combining prospectively collected biometry data from normal eyes of children <10 years old with biometry data from eyes undergoing cataract surgery. Refractive data from patients with a minimum of 5 visits over ≥5 years follow-up were used to calculate myopic shift and rate of refractive growth (RRG). Cataractous eyes that deviated from the middle quartiles of the age-adjusted normative values for axial length (AL) and keratometry were studied for variation in myopic shift and RRG to 5 years and last follow-up visit. Multivariable analysis was performed to determine the association between myopic shift and RRG and factors of age, sex, laterality, keratometry, AL, IOL power, and follow-up length. RESULTS: Normative values were derived from 100 eyes; there were 162 eyes in the cataract group with median follow-up of 9.6 years (Interquartile range[IQR], 7.3 to 12.2 years). Mean myopic shift ranged from 5.5 D (IQR, 6.3 to 3.5 D) for 0-2 year olds to 1.0 D (IQR, 1.5 to 0.6 D) for 8-10 year olds. Multivariable analysis showed more myopic shift was associated with younger age (p<.001), lower keratometry (p=.01), and male gender (p=.027); greater RRG was only associated with lower keratometry measures (p=.001). CONCLUSIONS: Age-based tables for IOL power selection are useful, and modest adjustments can be considered for eyes with lower keratometry values than expected for age.
Haptic and Haptic-Optic Junction Structural Integrity of CT Lucia and MA60 Intraocular Lenses. J Cataract Refract Surg 2021;.
Impact of Perioperative Dexmedetomidine Use in Cataract Surgery. J Cataract Refract Surg 2021;.
Intraoperative OCT versus Scheimpflug and Swept-Source OCT measurements for anterior eye parameters. J Cataract Refract Surg 2021;Abstract.
PURPOSE: To compare agreement of anterior segment parameter measurements using an intraoperative optical coherence tomography (iOCT) of a femtosecond laser (LenSx) during interface docking to the eye to preoperative Scheimpflug-tomography (Pentacam AXL) and swept-source optical coherence tomography (IOL Master 700). SETTING: Department of Ophthalmology, Goethe University, Frankfurt, Germany. DESIGN: Retrospective study. METHODS: Ninty-five eyes of 66 patients who had planned OCT-guided femtosecond laser-assisted lens surgery were included. Anterior segment measurements were performed in mydriasis prior to surgery using Scheimpflug-tomography and swept-source optical coherence tomography. After surgery iOCT images were analysed using a modification of the FIJI image processing program. Outcome measures included external anterior chamber depth (ACD), central corneal thickness (CCT) and central lens thickness (LT). RESULTS: The ACD measured with the iOCT was -0.011±0.126mm smaller (p=0.389) than with theswept-source OCT and -0.059±0.185mm than with the Scheimpflug-tomography (p=0.003). The swept-source OCT measures a -0.047±0.146mm smaller ACD than the Scheimpflug-tomography (p=0.002). The measurements of CCT using the iOCT and the Scheimpflug-tomography (-0.705±20.837μm, p=0.742) and the LT measurements of swept-source OCT and iOCT (-0.050±0.089mm, p<0.001) show no clinically relevant difference. Just the ACD between the iOCT and the Scheimpflug-tomography shows a clinically relevant difference. CONCLUSION: The comparison of the anterior segment parameters of intraoperative optical coherence tomography with swept-source optical coherence tomography showed no clinically relevant differences regarding the ACD and the lens thickness. However, Scheimpflug-tomography versus intraoperative optical coherence tomography measures a small clinically relevant difference for ACD.
Hallmarks of lens aging and cataractogenesis. Exp Eye Res 2021;210:108709.Abstract.
Lens homeostasis and transparency are dependent on the function and intercellular communication of its epithelia. While the lens epithelium is uniquely equipped with functional repair systems to withstand reactive oxygen species (ROS)-mediated oxidative insult, ROS are not necessarily detrimental to lens cells. Lens aging, and the onset of pathogenesis leading to cataract share an underlying theme; a progressive breakdown of oxidative stress repair systems driving a pro-oxidant shift in the intracellular environment, with cumulative ROS-induced damage to lens cell biomolecules leading to cellular dysfunction and pathology. Here we provide an overview of our current understanding of the sources and essential functions of lens ROS, antioxidative defenses, and changes in the major regulatory systems that serve to maintain the finely tuned balance of oxidative signaling vs. oxidative stress in lens cells. Age-related breakdown of these redox homeostasis systems in the lens leads to the onset of cataractogenesis. We propose eight candidate hallmarks that represent common denominators of aging and cataractogenesis in the mammalian lens: oxidative stress, altered cell signaling, loss of proteostasis, mitochondrial dysfunction, dysregulated ion homeostasis, cell senescence, genomic instability and intrinsic apoptotic cell death.
Fall risk in patients with pseudophakic monovision. Can J Ophthalmol 2021;Abstract.
OBJECTIVE: Vision changes can precipitate falls in the elderly resulting in significant morbidity and mortality. We hypothesized that pseudophakic monovision and ensuing anisometropia and aniseikonia impact elderly fall risk. This study assessed fall risk in patients with pseudophakic monovision, pseudophakic single vision distance (classic cataract surgery), and cataracts with no surgery. DESIGN: Retrospective single-institution cohort study PARTICIPANTS: Patients with bilateral cataracts diagnosed at 60 years of age or older who underwent bilateral cataract surgery (monovision or single vision distance) or did not undergo any cataract surgery (n = 13 385). Patients with unilateral surgery or a fall prior to cataract diagnosis were excluded. METHODS: Data were obtained from the Stanford Research Repository. Time-to-fall analysis was performed across all 3 groups. Primary outcome was hazard ratio (HR) for fall after second eye cataract surgery or after bilateral cataract diagnosis. RESULTS: Of 13 385 patients (241 pseudophakic monovision, 2809 pseudophakic single vision, 10 335 no surgery), 850 fell after cataract diagnosis. Pseudophakic monovision was not associated with fall risk after controlling for age, sex, and myopia. Pseudophakic single-vision patients had a decreased time to fall compared with no-surgery patients (log rank, p < 0.001). Older age at cataract diagnosis (HR =1.05, 95% confidence interval [CI] 1.04-1.06, p < 0.001) or at time of surgery (HR = 1.05, 95% CI 1.03-1.07, p < 0.001) increased fall risk, as did female sex (HR = 1.29, 95% CI 1.10-1.51, p = 0.002) and preexisting myopia (HR = 1.31, 95% CI 1.01-1.71, p = 0.046) among nonsurgical patients. CONCLUSIONS: Pseudophakic monovision did not impact fall risk, but pseudophakic single vision may increase falls compared with patients without cataract surgery.
Femtosecond Laser Assisted Cataract Surgery: A Review. Semin Ophthalmol 2021;36(8):618-627.Abstract.
Femtosecond laser assisted cataract surgery (FLACS) offers a level of precision, accuracy and customization that is not possible with manual phacoemulsification (MP). With the increase of patient expectations and premium intraocular lens utilization in the era of refractive cataract surgery, predictability and accuracy has become of utmost importance. FLACS has four main functions: creation of a consistently sized round capsulotomy, treatment of keratometric astigmatism with arcuate incisions, construction of clear corneal incisions, and fragmentation and/or softening of the lens. However, FLACS may have limitations due to suction loss, incomplete capsulotomy or poor pupillary dilation. Patient selection and surgeon experience is critical. This review article will focus on the various platforms available for FLACS, the steps in cataract surgery it can perform, and overall advantages and limitations of the technology.
Dropped Nucleus during Cataract Surgery in South India: Incidence, Risk Factors, and Outcomes. Ophthalmic Epidemiol 2021;:1-8.Abstract.
Purpose : To determine incidence, risk factors for, and outcomes of dropped nucleus (DN) during cataract surgery. Methods : This is a matched case-control study at the Aravind Eye Hospital in Madurai, India. Out of 184 consecutive DN cases, 171 were included. The case immediately preceding the DN case by the same surgeon served as matched concurrent control. The proportion of cataract surgeries with DN was calculated with a 95% confidence interval (CI). Conditional logistic regression was used to generate odds ratios for potential risk factors. Results : Among 415,487 consecutive cataract surgeries, incidence risk of DN was 0.044% [95% CI 0.038%, 0.051%], or 0.44 per 1,000 surgeries in 52 months. Significant preoperative risk factors were posterior polar cataract (adjusted odds ratio [aOR] 21.73, p = .003); suspected loose zonules (aOR 8.85, p < .001); older age (aOR 1.57, p = .001); and presence of diabetes mellitus (aOR 1.79, p = .03). Associated intraoperative complications included zonular dialysis (OR 34.49, p < .001), vitreous disturbance (OR 193.36, p < .001), and posterior capsule rent (OR 384.39, p < .001). Phacoemulsification and manual small incision cataract surgery did not significantly differ in DN incidence. DN most commonly occurred during nucleus removal (35.1%) or during/immediately following hydrodissection (24.0%). Visual outcomes of DN were worse than controls on average, but 51.9% achieved visual acuity 20/40 or better at 1 month. Conclusions : DN occurred rarely, with low absolute risk even when a strong risk factor was present. Nearly all cases followed posterior capsular rent or zonular dialysis, usually with observed vitreous loss. In spite of increased risk of postoperative complications in the DN group, the majority achieved favorable results.
Healthcare disparities contribute to missed follow-up visits after cataract surgery in the USA: results from the perioperative care for intraocular lens study. BMJ Open 2021;11(3):e038565.Abstract.
OBJECTIVE: To identify factors that contribute to missed cataract surgery follow-up visits, with an emphasis on socioeconomic and demographic factors. METHODS: In this retrospective cohort study, patients who underwent cataract extraction by phacoemulsification at Massachusetts Eye and Ear between 1 January and 31 December 2014 were reviewed. Second eye cases, remote and international patients, patients with foreign insurance and combined cataract cases were excluded. RESULTS: A total of 1931 cases were reviewed and 1089 cases, corresponding to 3267 scheduled postoperative visits, were included. Of these visits, 157 (4.8%) were missed. Three (0.3%) postoperative day 1, 40 (3.7%) postoperative week 1 and 114 (10.5%) postoperative month 1 visits were missed. Age<30 years (adjusted OR (aOR)=8.2, 95% CI 1.9 to 35.2) and ≥90 years (aOR=5.7, 95% CI 2.0 to 15.6) compared with patients aged 70-79 years, estimated travel time of >2 hours (aOR=3.2, 95% CI 1.4 to 7.4), smokers (aOR=2.7, 95% CI 1.6 to 4.8) and complications identified up to the postoperative visit (aOR=1.4, 95% CI 1.0 to 2.1) predicted a higher rate of missed visits. Ocular comorbidities (aOR=0.7, 95% CI 0.5 to 1.0) and previous visit best-corrected visual acuity (BCVA) of 20/50-20/80 (aOR=0.4, 95% CI 0.3 to 0.7) and 20/90-20/200 (aOR=0.4, 95% CI 0.2 to 0.9), compared with BCVA at the previous visit of 20/40 or better, predicted a lower rate of missed visits. Gender, race/ethnicity, language, education, income, insurance, alcohol use and season of the year were not associated with missed visits. CONCLUSIONS: Medical factors and demographic characteristics, including patient age and distance from the hospital, are associated with missed follow-up visits in cataract surgery. Additional studies are needed to identify disparities in cataract postoperative care that are population-specific. This information can contribute to the implementation of policies and interventions for addressing them.
Novel Method to Determine Target Refraction in Cataract Surgery for Patients Dependent on Therapeutic Scleral Lenses. Eye Contact Lens 2021;47(6):352-355.Abstract.
OBJECTIVES: To evaluate a novel approach to determine the refractive target for patients undergoing cataract surgery who are dependent on therapeutic scleral lenses, to avoid the need for postoperative scleral lens replacement. METHODS: Retrospective single-surgeon case series. The target refraction for intraocular lens selection was determined by considering the effective scleral lens system power. This was calculated by adding the known scleral lens spherical power to the difference between the scleral lens base curve and the average keratometry value. RESULTS: Six eyes from three patients with moderate myopia or emmetropia with ocular graft versus host disease dependent on therapeutic scleral lenses underwent cataract surgery with intraocular lens selection based on this method. All six eyes had corrected visual acuities of 20/30 or better while wearing their previous scleral lenses at the postoperative week 1 visit. All six eyes resumed full-time scleral lens use 1 week after phacoemulsification and did not require scleral lens replacement. CONCLUSIONS: Using this method, patients requiring therapeutic scleral lenses can quickly experience optimal vision, comfort, and ocular surface protection 1 week after cataract surgery. These patients can continue to use their existing scleral lenses and avoid the costs and burdens associated with lens replacement.
Preoperative Medical Testing and Falls in Medicare Beneficiaries Awaiting Cataract Surgery. Ophthalmology 2021;128(2):208-215.Abstract.
PURPOSE: Delaying cataract surgery is associated with an increased risk of falls, but whether routine preoperative testing delays cataract surgery long enough to cause clinical harm is unknown. We sought to determine whether the use of routine preoperative testing leads to harm in the form of delayed surgery and falls in Medicare beneficiaries awaiting cataract surgery. DESIGN: Retrospective, observational cohort study using 2006-2014 Medicare claims. PARTICIPANTS: Medicare beneficiaries 66+ years of age with a Current Procedural Terminology claim for ocular biometry. METHODS: We measured the mean and median number of days between biometry and cataract surgery, calculated the proportion of patients waiting ≥ 30 days or ≥ 90 days for surgery, and determined the odds of sustaining a fall within 90 days of biometry among patients of high-testing physicians (testing performed in ≥ 75% of their patients) compared with patients of low-testing physicians. We also estimated the number of days of delay attributable to high-testing physicians. MAIN OUTCOME MEASURES: Incidence of falls occurring between biometry and surgery, odds of falling within 90 days of biometry, and estimated delay associated with physician testing behavior. RESULTS: Of 248 345 beneficiaries, 16.4% were patients of high-testing physicians. More patients of high-testing physicians waited ≥ 30 days and ≥ 90 days to undergo surgery (31.4% and 8.2% vs. 25.0% and 5.5%, respectively; P < 0.0001 for both). Falls before surgery in patients of high-testing physicians increased by 43% within the 90 days after ocular biometry (1.0% vs. 0.7%; P < 0.0001). The adjusted odds ratio of falling within 90 days of biometry in patients of high-testing physicians versus low-testing physicians was 1.10 (95% confidence interval [CI], 1.03-1.19; P = 0.008). After adjusting for surgical wait time, the odds ratio decreased to 1.07 (95% CI, 1.00-1.15; P = 0.06). The delay associated with having a high-testing physician was approximately 8 days (estimate, 7.97 days; 95% CI, 6.40-9.55 days; P < 0.0001). Other factors associated with delayed surgery included patient race (non-White), Northeast region, ophthalmologist ≤ 40 years of age, and low surgical volume. CONCLUSIONS: Overuse of routine preoperative medical testing by high-testing physicians is associated with delayed surgery and increased falls in cataract patients awaiting surgery.
Visual outcomes after cataract surgery among the elderly residents in the 'homes for the aged' in South India: the Hyderabad Ocular Morbidity in Elderly Study. Br J Ophthalmol 2021;105(8):1087-1093.Abstract.
BACKGROUND/AIM: To report visual outcomes and factors associated with good visual outcomes after cataract surgery among the elderly residents in 'homes for the aged' in Hyderabad, India. METHODS: Individuals aged ≥60 years were recruited from 41 'homes for the aged'. All participants had a detailed eye examinations including visual acuity (VA) assessment , refraction, slit-lamp examination and fundus imaging by trained professionals. A detailed history of cataract surgery was recorded. Multivariate logistic regression was used to determine the factors associated with good visual outcomes after cataract surgery which was defined as presenting VA of 6/18 or better in the operated eye. Visual impairment (VI) is defined as presenting VA worse than 6/18 in the operated eye. RESULTS: 1215 eyes of 703 individuals had cataract surgery. The mean age of these participants was 77.5 years (SD: 8.2 years; range: 60-108 years), 66.8% were women, 29.9% reported diabetes and 61% reported hypertension. 406/1215 (33.4%; 95% CI 30.8 to 36.1) eyes had VI after cataract surgery. Posterior capsular opacification (31.8%; n=129) was the leading cause of VI followed by uncorrected refractive error (24.1%; n=98). The prevalence of good outcomes was 66.6% (95% CI 63.8 to 69.2). On applying multivariable analysis, younger age, self-reported hypertension, independent mobility, surgery in a non-government (as opposed to private) hospital and undergoing paid surgery were associated with good outcomes. CONCLUSIONS: One-third of the eyes of elderly individuals living in homes for the aged that had previously undergone cataract surgery had VI. Regular eye examinations with the provision of laser capsulotomy and appropriate refractive correction can substantially improve their vision.
Regulation of Connexin Gap Junctions and Hemichannels by Calcium and Calcium Binding Protein Calmodulin. Int J Mol Sci 2020;21(21)Abstract.
Connexins are the structural components of gap junctions and hemichannels that mediate the communication and exchange of small molecules between cells, and between the intracellular and extracellular environment, respectively. Connexin (Cx) 46 is predominately expressed in lens fiber cells, where they function in maintaining the homeostasis and transparency of the lens. Cx46 mutations are associated with impairment of channel function, which results in the development of congenital cataracts. Cx46 gap junctions and hemichannels are closely regulated by multiple mechanisms. Key regulators of Cx46 channel function include Ca and calmodulin (CaM). Ca plays an essential role in lens homeostasis, and its dysregulation causes cataracts. Ca associated CaM is a well-established inhibitor of gap junction coupling. Recent studies suggest that elevated intracellular Ca activates Cx hemichannels in lens fiber cells and Cx46 directly interacts with CaM. A Cx46 site mutation (Cx46-G143R), which is associated with congenital Coppock cataracts, shows an increased Cx46-CaM interaction and this interaction is insensitive to Ca, given that depletion of Ca reduces the interaction between CaM and wild-type Cx46. Moreover, inhibition of CaM function greatly reduces the hemichannel activity in the Cx46 G143R mutant. These research findings suggest a new regulatory mechanism by which enhanced association of Cx46 with CaM leads to the increase in hemichannel activity and dysregulation may lead to cataract development. In this review, we will first discuss the involvement of Ca/CaM in lens homeostasis and pathology, and follow by providing a general overview of Ca/CaM in the regulation of Cx46 gap junctions. We discuss the most recent studies concerning the molecular mechanism of Ca/CaM in regulating Cx46 hemichannels. Finally, we will offer perspectives of the impacts of Ca/CaM and dysregulation on Cx46 channels and vice versa.