Scheimpflug lens densitometry and ocular wavefront aberrations in patients with mild nuclear cataract.

PURPOSE: To test correlations between Scheimpflug optical densitometry and ocular higher-order aberrations (HOAs) in patients with mild nuclear cataract. SETTING: Cornea and Refractive Surgery Department, Hospital de Braga, Braga, Portugal. DESIGN: Retrospective single-center study. METHODS: In eyes with mild nuclear cataract, lens densitometry was evaluated by Scheimpflug imaging (Pentacam HR), which provided an objective quantification (mean density and maximum density) and grading (nuclear staging score) of the crystalline lens. A visual function analyzer that combines ray-tracing aberrometry and Placido disk-based topography (iTrace) was used to evaluate the total ocular and internal HOAs. RESULTS: The study comprised 40 eyes of 30 patients. The mean density of the lens nucleus was 8.99% ± 0.76% (SD) (range 7.5% to 10.8%), and the mean maximum density was 27.96% ± 6.97% (range 16.9% to 56.1%). Regarding the score of nuclear staging of the Scheimpflug device, 28 eyes had level 0 and 12 eyes had level 1. Significant positive correlations were found between the mean density and maximum density parameters and the internal HOAs (ρ = 0.661, P < .001 and ρ = 0.570, P < .001, respectively). CONCLUSIONS: There were significant correlations between the quantification parameters derived from Scheimpflug lens densitometry and ocular HOAs. The integration of these technologies can help in clinical decision making and in understanding the subjective symptoms of patients with mild nuclear cataracts. FINANCIAL DISCLOSURE: Dr. Ambrósio is a consultant to Oculus Optikgeräte GmbH, Alcon Surgical, Inc., and Carl Zeiss Meditec AG. None of the other authors has a financial or proprietary interest in any material or method mentioned.

Spherical aberration reduction in nuclear cataracts.

PURPOSE: To measure higher-order aberrations (HOAs) in nuclear cataracts and to investigate spherical aberration changes with nuclear cataract progression. METHODS: A total of 102 eyes of older subjects (>50 years) were classified based on the nuclear opalescence (NO) grading of the Lens Opacities Classification System III: Group 1 (< NO2, 35), 2 (NO2, 23), 3 (NO3, 23), and 4 (≥ NO 4:21 eyes). Wave front measurements were performed with a Hartmann-Shack aberrometer. To investigate lenticular spherical aberration, HOAs were examined in 28 eyes before and after phacoemulsification, followed by insertion of an aberration-free intraocular lens. The relationship between lens opacity grade and ocular and lenticular spherical aberrations were investigated. RESULTS: Mean spherical aberrations in groups 1, 2, 3, and 4 were 0.25 ± 0.10, 0.16 ± 0.13, 0.12 ± 0.15, and 0.10 ± 0.20 µm, respectively, and showed a significant difference with nuclear opacity grading (p = 0.001). The spherical aberration showed negative associations with nuclear opacity grading (r = -0.408, p < 0.001). The predominant change in HOAs after phacoemulsification was an increase in spherical aberration, and 86 % of lenticular spherical aberrations were presumed to have negative values. The lenticular spherical aberration was negatively correlated with nuclear opacity severity (r = -0.409, p = 0.031). CONCLUSIONS: Ocular spherical aberration decreases with the progression of nuclear cataracts due to the negative correlation between lenticular spherical aberration and nuclear opacity severity.

[Comparison study of new nucleus fragmentation technique in dense cataract phacoemulsification].

Comparison study of new fragmentation technique of dense nucleus in ultrasound phacoemulsification is performed. Proposed method of dense nucleus fragmentation allows to decrease equivalent time of ultrasound exposure using Ozil and NeoSoniX techniques. Minimal loss of corneal posterior epithelial cells was showed in combination of developed nucleus fragmentation technique with torsional phacoemulsification (Ozil). Combination of new fragmentation technique of dense nucleus (IV stage) with Ozil technique results in significant decrease of surgical trauma and time of rehabilitation.

Comparative analysis of the nuclear lens opalescence by the Lens Opacities Classification System III with nuclear density values provided by Oculus Pentacam: a cross-section study using Pentacam Nucleus Staging software.

PURPOSE: To compare the clinical classification of cataract using the Lens Opacities Classification System (LOCS) III with the mean values of lens density provided by the Pentacam Scheimpflug System in nuclear cataracts. METHODS: One hundred and one eyes from 101 patients with age-related nuclear cataract were submitted to clinical examination for lens grading score using LOCS III. According to LOCS III, nuclear opalescence was divided in six groups. Patients were evaluated by the Pentacam Scheimpflug System for the mean lens density using the Pentacam lens densitometry program (PLDP), the Pentacam Nucleus Staging (PNS) mean value and the PNS cataract grading score. RESULTS: A positive correlation between the mean values of lens density and LOCS III classification, considering groups 1 to 5, could be noticed with PLDP and PNS mean value. The mean values between the groups were similar using the PLDP and the PNS mean value. However, when the PNS cataract grading score was evaluated, there was low correspondence with LOCS III classification. CONCLUSION: Pentacam Scheimpflug device offers an objective measure of the lens nuclear density on nuclear cataracts. PLDP and the PNS mean value were both useful to evaluate age-related nuclear cataract up to LOCS III group 5.

Comparative analysis of the nuclear lens opalescence by the Lens Opacities Classification System III with nuclear density values provided by Oculus Pentacam: a cross-section study using Pentacam Nucleus Staging software / Análise comparativa da opalencência nuclear cristaliniana pelo Lens Opacities Classification System III com valores de densidade nuclear fornecidos pelo Oculus Pentacam: estudo transversal utilizando o Pentacam Nucleus Staging software

PURPOSE: To compare the clinical classification of cataract using the Lens Opacities Classification System (LOCS) III with the mean values of lens density provided by the Pentacam Scheimpflug System in nuclear cataracts. METHODS: One hundred and one eyes from 101 patients with age-related nuclear cataract were submitted to clinical examination for lens grading score using LOCS III. According to LOCS III, nuclear opalescence was divided in six groups. Patients were evaluated by the Pentacam Scheimpflug System for the mean lens density using the Pentacam lens densitometry program (PLDP), the Pentacam Nucleus Staging (PNS) mean value and the PNS cataract grading score. RESULTS: A positive correlation between the mean values of lens density and LOCS III classification, considering groups 1 to 5, could be noticed with PLDP and PNS mean value. The mean values between the groups were similar using the PLDP and the PNS mean value. However, when the PNS cataract grading score was evaluated, there was low correspondence with LOCS III classification. CONCLUSION: Pentacam Scheimpflug device offers an objective measure of the lens nuclear density on nuclear cataracts. PLDP and the PNS mean value were both useful to evaluate age-related nuclear cataract up to LOCS III group 5.

OBJETIVO: Comparar a classificação clínica de catarata nuclear, utilizando o Lens Opacities Classification System (LOCS) III, e o valores médios de densidade nuclear fornecido pelo sistema Pentacam Sheimpflug. MÉTODOS: Cento e um pacientes (101 olhos) com diagnóstico de catarata nuclear senil foram submetidos a exame clínico para graduação da opalescência nuclear de acordo com o LOCS III e divididos em seis grupos de acordo com a mesma. Os pacientes foram posteriormente avaliados pelo sistema Pentacam Scheimpflug para obtenção do valor médio de densidade fornecido pelo programa de densitometria cristaliniana do aparelho (PLDP), valor médio de densidade calculado pelo Pentacam Nucleus Staging software (PNS) e o escore de graduação de catarata nuclear fornecido pelo PNS. RESULTADOS: Observou-se uma correlação positiva entre os valores médios de densidade cristaliniana fornecidos pelo PLDP e PNS e a classificação clínica LOCS III, considerando os grupos 1 ao 5. Os valores médios de densidade nuclear de cada grupo foram similares utilizando dados do PLDP e PNS. Entretanto, quando foi analisado o escore de graduação da catarata fornecido pelo PNS foi observada uma baixa correspondência com a classificação LOCS III. CONCLUSÃO: O Pentacam Scheimpflug oferece uma medida objetiva da densidade nuclear cristaliniana em cataratas nucleares. Os valores médios de densidade nuclear fornecidos pelo PLDP e PNS foram úteis na avaliação de catarata nuclear senil até o grupo 5 da classificação LOCS III.

Use of cobalt blue light in grading cataract and estimating vision loss.

PURPOSE: To test an anecdotally reported cataract grading system predictive of a 20/50 visual threshold in cataract-induced vision loss using cobalt blue light. SETTING: Hennepin County Medical Center, Minneapolis, Minneapolis VA Medical Center, Minneapolis, and Regions Hospital, St. Paul, Minnesota, USA. METHODS: Four observers evaluated pure nuclear cataracts using a standardized cobalt-blue-light protocol. Observers graded a nuclear cataract as positive if the posterior capsule was visualized with cobalt blue light and negative if the posterior capsule was not visualized. Results of the grading were compared with cataract-induced vision loss in an attempt to establish a threshold for lost visual acuity in grading cataracts with cobalt blue light. The study design was prospective observation of a cohort with a visually significant cataract. RESULTS: This study did not show a clear visual acuity threshold for cataract-induced vision loss using a standardized cobalt-blue-light protocol. Overall, 26.3% (95% confidence interval, 13.4-40.2) of all 20/40 or less dense nuclear cataracts had visible posterior capsules using cobalt blue light, with good estimated interobserver agreement. CONCLUSIONS: Although cobalt blue light is selectively absorbed by yellow pigment in an aging nuclear cataract, its ability to predict visual acuity loss due to lens opacity was limited.

Correlation of lens density measured using the Pentacam Scheimpflug system with the Lens Opacities Classification System III grading score and visual acuity in age-related nuclear cataract.

AIMS: To investigate the relationship between lens density measured with the Pentacam Scheimpflug System and grading score using the Lens Opacities Classification System (LOCS) III as well as that between lens density and visual acuity in age-related nuclear cataract patients. METHODS: Lens density and grading score were evaluated in 138 cases (180 eyes) with age-related nuclear cataract. LogMAR visual acuity was tested with the Early Treatment Diabetic Retinopathy Study chart. The correlations between lens density value and LOCS III nuclear opacity (NO) and nuclear colour (NC) grading score and that between lens density value and logMAR visual acuity were analysed. RESULTS: There was a linear increasing relationship between lens density value and LOCS III grading score in nuclear cataract patients. Lens density value had a stronger significant correlation with LOCS III NO score than that with NC score. The correlation between the nuclear lens density value and logMAR visual acuity was stronger than that between NO score and logMAR visual acuity or between NC score and logMAR visual acuity. CONCLUSION: Lens density as a quantitative and objective parameter can present the degree of NO and associated visual impairment due to nuclear cataract. The LOCS III criterion as an economic cataract grading system provides data that are in satisfactory concordance with the results obtained using the Pentacam Scheimpflug system.

Higher-order aberrations of age-related cataract.

PURPOSE: To analyze higher-order aberrations induced by different types of lenticular opacities. SETTING: Federal University of São Paulo, São Paulo, Brazil. METHODS: One hundred thirty-eyes of 65 patients with bilateral cataract, classified according to the Lens Opacities Classification System III (LOCS III), had complete ophthalmic examinations, corneal topography (EyeSys Technologies), and wavefront analysis (LADARWave, Alcon Laboratories). Patients with cataracts that could not be measured by a Hartmann-Shack sensor or those with coexisting ocular disease were excluded. Higher-order aberrations were compared between the nuclear, cortical, and posterior subcapsular groups for statistical significance. RESULTS: One hundred five eyes of 65 patients were assessed. Twenty-eight eyes (23.33%) had predominantly nuclear opacification (NO1-NO6 and C1-2), and 13 (10.83%) had mainly cortical opacification (C1-4). Sixty-four eyes (65.83%) had a mixed pattern of LOCS III classification, which hindered the establishment of a correlation between the aberrometry and cataract type. Eighteen eyes that presented with dense posterior subcapsular cataract (P4-5) and 7 eyes with cortical C5 LOCS III classification were excluded. In eyes with nuclear opacification, the mean spherical aberration with a 6.0 mm pupil was 0.45 microm +/- 0.17 (SD) and the mean coma was 0.29 +/- 0.13 microm. In eyes with predominantly cortical cataract, the mean spherical aberration was 0.12 +/- 0.10 microm and the mean coma was 0.49 +/- 0.23 microm. The cortical cataract group had statistically significantly higher coma than the other groups (P<.001). The nuclear cataract group had statistically significantly higher spherical aberrations than the other groups (P<.001). CONCLUSIONS: Different types of early lenticular opacities induced different wavefront aberration profiles. Coma predominated in the cortical cataract group, and spherical aberration predominated in the nuclear cataract group.

[Characteristics of non invasive ultrasound determination of mechanical lens hardness].

Sixty-two patients with varying maturity cataract were examined to assess a new noninvasive method for determining the mechanical hardness of the nucleus of the lens. There was an inverse relation of the hardness of the nucleus to its relative acoustic density (delta). Comparison of the ultrasound density of the lens and the mechanical characteristics of its nucleus has provided the following classification: the lens hardness is high at delta of 0 to 0.2; average at 0.3 to 0.5, and low at 0.6 or higher. Determination of relative acoustic density by measuring the parameter delta substantially enhances the accuracy ofpreoperative prediction of the hardness of the nucleus of the lens when a surgical option for cataract removal is chosen.

Presbyopia: the first stage of nuclear cataract?

Presbyopia, the inability to accommodate, affects almost everyone at middle age. Recently, it has been shown that there is a massive increase in the stiffness(1) of the lens with age and, since the shape of the lens must change during accommodation, this could provide an explanation for presbyopia. In this review, we propose that presbyopia may be the earliest observable symptom of age-related nuclear (ARN) cataract. ARN cataract is a major cause of world blindness. The genesis of ARN cataract can be traced to the onset of a barrier within the lens at middle age. This barrier restricts the ability of small molecules, such as antioxidants, to penetrate into the centre of the lens leaving the proteins in this region susceptible to oxidation and post-translational modification. Major protein oxidation and colouration are the hallmarks of ARN cataract. We postulate that the onset of the barrier, and the hardening of the nucleus, are intimately linked. Specifically, we propose that progressive age-dependent hardening of the lens nucleus may be responsible for both presbyopia and ARN cataract.

Long-term nutrient intake and 5-year change in nuclear lens opacities.

OBJECTIVE: To determine if usual nutrient intake is related to a 5-year change in the amount of lens nuclear opacification assessed by computer-assisted image analysis. DESIGN: A sample of 408 Boston, Mass-area women from the Nurses' Health Study aged 52 to 74 years at baseline participated in a 5-year study related to nutrition and vision. Usual nutrient intake was calculated as the average intake from 5 food frequency questionnaires that were collected over a 13- to 15-year period before the baseline evaluation of lens nuclear density. Duration of vitamin supplement use before baseline was determined from 7 questionnaires collected during this same period. We assessed the degree of nuclear density (opacification) using computer-assisted image analysis of digital lens images with amount of nuclear density measured as a function of average pixel gray scale, ranging from 0 (clear) to 255 (black). RESULTS: Median (range) baseline and follow-up nuclear densities were 44 (19 to 102) and 63 (32 to 213). The median (range) 5-year change in nuclear density was 18 (-29 to 134) and was positively correlated with the amount of opacification at baseline (Spearman correlation coefficient = 0.35; P<.001). Geometric mean 5-year change in nuclear density was inversely associated with the intake of riboflavin (P trend = .03) and thiamin (P trend = .04) and duration of vitamin E supplement use (P trend = .006). CONCLUSION: Our results suggest that long-term use of vitamin E supplements and higher riboflavin and/or thiamin intake may reduce the progression of age-related lens opacification.

Distribution, spherical structure and predicted Mie scattering of multilamellar bodies in human age-related nuclear cataracts.

PURPOSE: To characterize multilamellar bodies (MLBs), determine their distribution along the optic axis and predict their potential Mie scattering within human age-related nuclear cataracts. Previous studies restricted to the equatorial plane have shown that MLBs are rare spherical objects that are 1-4 microm in diameter and covered by multiple layers of thin lipid-rich membranes. METHODS: Eight human aged transparent lenses were obtained from eye bank donors and eight human age-related nuclear cataracts were obtained immediately after extracapsular extraction. Each sample was Vibratome sectioned fresh into 200 microm thick sections that were fixed and embedded for light or electron microscopy. Light micrograph montages of the optic axis containing the juvenile, fetal and embryonic nuclei were examined. Mie scattering for random coated spherical particles was calculated based on assumed and measured particle parameters. RESULTS: Cells along the optic axis of the cataract contained approximately 7.5 times more MLBs as similar regions of the aged transparent lens, although these MLBs occurred with extremely low frequency. Cells of the aged transparent lens contained 1.3 MLBs mm(-2), while those of the cataract contained 9.6 MLBs mm(-2), which are equivalent to calculated densities of 5.6 x 10(2) and 4.1 x 10(3)mm(-3), respectively. While some MLBs were located within the cytoplasm near cell membranes, others were found away from membranes. The MLBs are distinct from circular profiles resulting from finger-like projections between adjacent cells. MLBs displayed varying geometries and cytoplasmic textures, although predominately spherical with interiors similar to adjacent fiber cell cytoplasm. These results are in agreement with previous theoretical analysis of light scattering from human lenses and with previous morphological studies examining the equatorial plane of the lens. Potential Mie scattering of spherical particles with the average properties of the observed MLBs and assumed refractive index properties was calculated to be forward scattering of as much as 20% of the incident light. CONCLUSIONS: The observed low frequency and absence of clustering of MLBs in the equatorial plane and along the optic axis suggests that MLBs are most likely uniformly distributed throughout the embryonic, fetal and juvenile nuclei of age-related cataracts. Because of their size, distribution, textured cytoplasm and calculated Mie scattering, MLBs probably cause local fluctuations in refractive index in human lens nuclei and, therefore, are potential sources of low-angle, forward light scattering that could impair image formation.

Changes in the internal structure of the human crystalline lens with age and accommodation.

Scheimpflug images were made of the unaccommodated and accommodated right eye of 102 subjects ranging in age between 16 and 65 years. In contrast with earlier Scheimpflug studies, the images were corrected for distortion due to the geometry of the Scheimpflug camera and the refraction of the cornea and the lens itself. The different nuclear and cortical layers of the human crystalline lens were determined using densitometry and it was investigated how the thickness of these layers change with age and accommodation. The results show that, with age, the increase in thickness of the cortex is approximately 7 times greater than that of the nucleus. The increase in thickness of the anterior cortex was found to be 1.5 times greater than that of the posterior cortex. It was also found that specific parts of the cortex, known as C1 and C3, showed no significant change in thickness with age, and that the thickening of the cortex is entirely due to the increase in thickness of the C2 zone. With age, the distance between the sulcus (centre of the nucleus) and the cornea does not change. With accommodation, the nucleus becomes thicker, but the thickness of the cortex remains constant.

Loss of heterozygosity in patients with pseudoexfoliation syndrome.

PURPOSE: The purpose of the study was to evaluate the possible occurrence of loss of heterozygosity (LOH) in the anterior capsule, lens nucleus, iris, and trabeculum samples taken from patients with pseudoexfoliation syndrome (PEX). Loss of heterozygosity in a microsatellite marker locus indicates that the neighboring gene may be inactivated. Previous attempts to find a gene defect that might be responsible for pseudoexfoliation glaucoma have been unsuccessful. METHODS: Specimens of the anterior capsule, the lens nucleus, the iris, the trabeculum, and reference blood samples were collected from 19 PEX patients. Fluorescent multiplex PCR was used to amplify the microsatellite markers located on chromosomes 2, 4, 7, 12, 18, 19, and 21. RESULTS: LOH was found in 58% of the iris specimens and 50% of the anterior capsule specimens collected from PEX patients. The highest incidence of LOH was observed at the marker D7S820. CONCLUSIONS: It is possible, that genetic factors may be involved in the etiology and pathogenesis of PEX.

Efficacy and safety of the soft-shell technique in cases with a hard lens nucleus.

PURPOSE: To evaluate the efficacy and safety of the soft-shell technique in reducing corneal endothelial cell damage during cataract surgery in patients with a hard lens nucleus. SETTING: Miyata Eye Hospital, Miyakonojo, Miyazaki, Japan. METHODS: Sixty eyes of 57 cataract patients with a hard lens nucleus (Emery-Little classification grade 3 or higher) had phacoemulsification using the soft-shell technique with Healon((R)) (sodium hyaluronate 1%) and Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) (soft-shell group) or with Healon alone (control group). The visual acuity, intraocular pressure (IOP), flare intensity in the anterior chamber, central corneal thickness, and corneal endothelial cell density were evaluated postoperatively. RESULTS: There were no significant IOP elevations in either group. The mean central corneal thickness in the control group was 539 microm +/- 26.0 (SD) preoperatively and 578 +/- 52.0 microm 1 day after surgery; the increase was significant (P =.0154). There was no significant change in the central corneal thickness in the soft-shell group. There were no statistically significant differences between the 2 groups in uncorrected visual acuity, best corrected visual acuity, IOP, flare intensity in the anterior chamber, and central corneal thickness throughout the follow-up. The rate of endothelial cell loss 3 months after surgery was 6.4% +/- 9.6% in the soft-shell group and 16.3% +/- 9.8% in the control group (P =.0003). CONCLUSION: The results suggest that the soft-shell technique is safe and effective in protecting corneal endothelial cells during cataract surgery in patients with a hard lens nucleus.

The relationship between nuclear colour and opalescence on the LOCSIII scale and physical characteristics of cataract nuclei.

PURPOSE: To evaluate the compression characteristics of the human lens nucleocortex in relation to its LOCSIII clinical grading. METHODS: Sixteen subjects undergoing planned extracapsular cataract surgery had pre-operative slit-lamp examination and assessment of cataract LOCSIII grade followed by postoperative in vitro evaluation of the nucleus with measurement of 'linear compressibility' by a purpose-designed caliper incorporating a strain gauge, enabling the derivation of a graph of nuclear compression (D (mm) against applied force (F (N)). RESULTS: Nuclear colour correlates with the force required to compress a lens to 75% of its original depth (F75) (R = 0.625, P = 0.017). Nuclear opalescence correlates with the force required to compress a lens to 75% of its original depth (R = 0.651, P = 0.012) and inversely with linear compressibility (DeltaD/DeltaF, the slope of the graph of nuclear compression against applied force) (R = -0.610, P = 0.014). F75 is a direct and linear compressibility is an inverse related parameter of lens nucleus 'hardness'. CONCLUSION: A new instrument is described which allows measurement of 'hardness'-related compression characteristics of the human cataract in vitro. There is a relationship between the LOCSIII clinical classification of nuclear cataracts and mechanical compression characteristics of the cataractous lens. LOCSIII classification may aid the preoperative planning of an appropriate surgical approach to an individual cataract.

Glutathione peroxidase-1 deficiency leads to increased nuclear light scattering, membrane damage, and cataract formation in gene-knockout mice.

PURPOSE: Previous in vitro studies with transgenic and gene-knockout mice have shown that lenses with elevated levels of glutathione peroxidase (GPX)-1 activity are able to resist the cytotoxic effect of H(2)O(2), compared with normal lenses and lenses from GPX-1-deficient animals. The purpose of this study was to investigate the functional role of this enzyme in antioxidant mechanisms of lens in vivo by comparing lens changes of gene-knockout mice with age-matched control animals. METHODS: In vivo lens changes were monitored by slit lamp biomicroscopy, and enucleated lenses were examined under a stereomicroscope in gene-knockout animals and age-matched control animals ranging in age from 3 weeks to 18 months. Transmission (TEM) and confocal microscopy were performed on different regions of lenses after the mice were killed at various times. RESULTS: Slit lamp images showed an increase in nuclear light scattering (NLS) in gene-knockout mice compared with control animals. TEM revealed changes in the nucleus as early as 3 weeks of age by the appearance of waviness of fiber membranes. With increasing age, there was greater distortion of fiber membranes and distension of interfiber space at the apex of fiber cells compared with control mice. The changes in nuclear fiber membranes were even more dramatic, as observed by confocal microscopy, which was performed on thicker sections. In contrast to the changes in the lens nucleus, the morphology of the epithelium and superficial cortex remained unchanged in knockout animals during the same experimental period, consistent with slit lamp observations. Stereomicroscopy of ex vivo lenses demonstrated a significant increase in opacification in gene-knockout mice relative to control animals of the same age. This effect became evident in mice aged 5 to 9.9 months and persisted thereafter in older animals, resulting in mature cataracts after 15 months. CONCLUSIONS: The results demonstrate the critical role of GPX-1 in antioxidant defense mechanisms of the lens nucleus. The increased NLS appears to be associated with damage to fiber membranes in the nucleus, which is particularly susceptible to oxidative challenge because of the deficiency of GPX-1. It is suggested that the lens membrane changes in the knockout animals may be due to the formation of lipid peroxides, which serve as substrates for GPX-1. Cataract development in gene-knockout mice appeared to progress from focal opacities, apparent at an earlier age, to lamellar cataracts between 6 and 10 months, and finally to complete opacification in animals older than 15 months. This is the first reported phenotype in GPX-1-knockout mice.

Assessment of nuclear sclerosis after nonvitrectomizing vitreous surgery.

PURPOSE: Nuclear sclerosis develops frequently after successful pars plana vitrectomy. We evaluated changes in the degree of nuclear sclerosis after nonvitrectomizing vitreous surgery for idiopathic epimacular proliferation. METHODS: Forty-one consecutive patients (41 eyes) underwent removal of idiopathic epimacular proliferation by nonvitrectomizing vitreous surgery and were followed postoperatively for at least 12 months. Visual acuity, refractive error, slit-lamp biomicroscopy, and Scheimpflug photographs were assessed preoperatively and postoperatively to evaluate changes in the degree of lenticular opacification. Quantitative analysis of the nuclear sclerosis was performed by densitometry with Scheimpflug photographs performed on only the last 21 patients. We evaluated these measurements by comparing statistically the preoperative and postoperative difference between both eyes (operative eye minus nonoperative ocular data). RESULTS: There was no significant difference in the progression of nuclear sclerosis or degree of myopic shift between the operated and fellow eyes during postoperative follow-up (mean +/- SD, 22 +/- 8 months; median, 22 months; range, 12 to 48 months). The average preoperative and postoperative refractive errors in operated eyes were 0.0 +/- 2.4 diopters and 0.1 +/- 2.5 diopters, respectively; the average difference in the refractive errors between both eyes was -0.2 +/- 0.7 diopter preoperatively and -0.2 +/- 0.9 diopter postoperatively (P =.961, paired t test). The average preoperative and postoperative nuclear density values by Scheimpflug photography in 21 operated eyes were, respectively, 72 +/- 18 nuclear density units and 75 +/- 17 nuclear density units; the average difference in nuclear density values between both eyes was -1 +/- 4 nuclear density units preoperatively and 0 +/- 6 nuclear density units postoperatively (P =.631, paired t test). CONCLUSION: Progression of nuclear sclerotic cataract based on changes in refractive error and Scheimpflug photography was not observed after nonvitrectomizing vitreous surgery.

Incidence and progression of lens opacities in the Barbados Eye Studies.

OBJECTIVE: To provide 4-year cumulative incidence and progression rates of age-related lens opacities in a population > or =40 years of age, which is mainly of African origin. DESIGN: Cohort study that reexamined surviving members of the population-based Barbados Eye Study 4 years after baseline. PARTICIPANTS: Three thousand four hundred twenty-seven members of the Barbados Eye Study cohort (85% of those eligible). MAIN OUTCOME MEASURES: The Lens Opacities Classification System II (LOCS II) was used at the slit lamp. Cumulative incidence was defined as the development of any nuclear, cortical or posterior subcapsular (PSC) opacities (LOCS II scores > or =2) among persons without that opacity type at baseline. Cumulative progression was defined by at least two-step increases in scores among persons with preexisting lens opacities. RESULTS: The incidence of cortical opacities was about five times greater in black than white participants (age-gender adjusted relative risk = 4.7; 95% confidence interval: 1.9-11.4). In the black population, the 4-year incidence rates were 22.2% (20.4%-24.0%) for any cortical, 9.2% (8.2%-10.4%) for any nuclear, and 3.3% (2.7%-4.0%) for any PSC opacities; rates increased greatly with age. Four-year progression rates were 12.5% for cortical, 3.6% for nuclear, and 23.0% for PSC opacities, without consistent pattern by age. Women had a greater risk of cortical and nuclear opacities (P<0.05) than men and greater progression of nuclear opacities. The presence of PSC opacities at baseline seemed to at least double the incidence and progression rates of other opacities. In persons initially opacity free, single cortical opacities were the predominant type to develop at followup. Visual acuity loss frequently accompanied incident opacities. CONCLUSIONS: This longitudinal study provides new population-based data on the natural history of lens opacities. Incidence and progression of opacities, especially of cortical opacities, were high. After 4 years of followup, 1 in 4 to 5 participants developed cortical opacities, 1 in 11 developed nuclear opacities, and 1 in 30 developed PSC opacities. The information obtained attests to the public health impact of age-related cataract, as well as its extent, in this and similar black populations.

Management of the dropped nucleus in phaco-emulsification [abstract]

Posterior capsular rupture is a common complication of phaco-emulsification of cataracts. This often results in vitreous prolapse and sometimes loss of cataract fragments into the vitreous cavity. Depending on the amount of lens material retained, inflammation can cause severe proliferative vitreo-retinopathy and also severe glaucoma. Both problems can result in the loss of eye. Timely intervention with vitreo-retinal surgery can reduce the morbidity and save sight. Newer instrumentation will now allow the safe removal of the entire lens by phaco-fragmentation in the vitreous cavity. The ability to safely carry out the manoevres required to remove the lens material is an important part of the armamentarium of the vitreo-retinal surgeon. Complications of the procedure include retinal detachment, choroidal haemorrhage, secondary glaucoma, endophthalmitis, macular scarring and corneal decompensation. (AU)