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PubMed1993

Continuous curvilinear (circular) capsulorhexis and planned extracapsular cataract extraction--are they compatible?

The successful use of continuous curvilinear (circular) capsulorhexis (CCC) in planned extracapsular cataract extraction (ECCE) is dependent on the feasibility of safe nuclear delivery through the smaller anterior capsular opening. Experimental evidence supports the proposition that the anterior capsular rim can stretch without tearing to dimensions which allow for safe nucleus delivery. Clinical reports of accidental intracapsular expression during nucleus delivery in CCC seemingly contradict the experimental evidence. This paper examines this apparent contradiction and presents clinical evidence in the form of a series of 210 cases of planned ECCE with CCC. The technique used and a detailed analysis of the operative complications are presented. The results indicate that using a modified technique for nucleus delivery, CCC and planned ECCE are fully compatible techniques.

Adult↗
PubMed1984

A new method of measuring in vivo the lens transmittance, and study of lens scatter, fluorescence and transmittance.

We propose a new method to measure in vivo nuclear transmittance using scanning photometry, thus complementing its present application in measuring lens scatter and fluorescence. We compared our method of measuring the transmittance with a previously reported in vivo method and found an adequate correlation. We then measured the fluorescence, scatter and transmittance of lenses without cataract and those with as much as a mild yellowing. The three phenomena correlated with age. In addition, this study allowed a correlation of the three phenomena with each other, indicating that the loss of transmittance of the nucleus cannot be explained by its thickening alone but that changes in its composition must take place. Finally, a preliminary study on diabetics showed early onset of the process responsible for the increase in lens fluorescence. This process did not seem to be accelerated in diabetics in comparison with normals. The nuclear scatter appeared to increase more rapidly with age in nondiabetics as compared to diabetics. This preliminary study suggests mainly that scanning photometry can be used to study aging and pathologic changes in the lens.

Absorption↗
PubMed1990

Objective measurement of cortical and subcapsular opacification in retroillumination photographs.

An image analysis system has been developed for the objective analysis of cortical opacification. Lens photographs are obtained using a Neitz CTR retroillumination camera. The images are digitized using an IBM-PC-based imaging system. We have developed a program, called OPAC, through which the computer analyzes the image using a circular grid consisting of 93 sectors. The program outputs the percent of lens area which is opaque. Ninety-eight photographs, previously classified by the Lens Opacities Classification System (LOCS II), were analyzed using OPAC as well as a manual, square-grid counting system (GRID). The results show a linear correlation between OPAC and GRID with a correlation coefficient of 0.94. The results obtained with OPAC are also linearly correlated with the LOCS II classifications.

Cataract↗
PubMed1990

Subjective (LOCS II) versus objective (BGS) measures of cortical and subcapsular cataracts in retroillumination photographs.

96 black-and-white Neitz retroillumination photographs were graded subjectively using the Lens Opacities Classification System Version II (LOCS II). They were also measured objectively using the background subtraction (BGS) analysis. Subjective and objective BGS gradings were compared and showed good agreement (kappa = 0.78 for cortical and 0.78 for posterior subcapsular cataracts) and good correlation (correlation coefficient = 0.82 for cortical and 0.84 for posterior subcapsular cataracts; Spearman rank analysis).

Cataract↗
PubMed1982

Synthesis of cytoskeletal and membrane polypeptides by the organ cultured chicken lens.

The synthesis of cytoskeletal and membrane polypeptides of the chick lens epithelium, superficial cortical fiber cells and deep cortical fiber cells was studied in the organ-cultured lens. The synthetic activity of the cytoskeletal polypeptides was restricted to the epithelium and superficial cortical fiber cells while membrane polypeptides were synthesized by deep cortical fiber cells as well. None of the polypeptides was observed to be synthesized by the lens nuclear fiber cells.

Animals↗
PubMed1994

Risk factors for cortical, nuclear, posterior subcapsular and mixed cataract: a case-control study.

A case-control study was conducted to evaluate risk factors for cortical, nuclear, posterior subcapsular and mixed cataract. The 385 cases and 215 controls (age range 40-75 yrs) included in the study underwent a complete ophthalmological examination and laboratory blood tests, and were interviewed about behavioral variables, environmental exposure and their medical history. Lens opacity was classified using the 'Lens Opacity Classification System II' (LOCS II). On multivariate analysis, the risk factors for cortical cataract were the presence of diabetes for more than five years (OR = 3.7) and increased serum K+ and Na+ levels. A history of surgery under general anesthesia and the use of sedative drugs were associated with reduced risk (OR = 0.4). Posterior subcapsular cataract was associated with the use of steroids (OR = 18.2) and diabetes (OR = 8.1), and nuclear cataract with calcitonin (OR = 5.7) and milk intake (OR = 0.25). Mixed cataract was associated with a history of surgery under general anesthesia (OR = 0.5). Some of these results are consistent with the findings of similar studies performed in different geographical areas, others are not. The results suggest a possible role of electrolyte imbalance in the development of senile cataract.

Adult↗
PubMed1997

LOCS III versus the Oxford Clinical Cataract Classification and Grading System for the assessment of nuclear, cortical and posterior subcapsular cataract.

PURPOSE: To compare two methods of cataract grading for nuclear cataract, cortical cataract and posterior subcapsular cataract. METHODS: The Melton Eye Study is an English community-based epidemiological study of the natural history of eye disease in people aged 55 to 74 years. The lenses of both eyes of 560 subjects were graded at the slit lamp using two cataract grading systems. The Oxford Clinical Cataract Classification and Grading System (OCCCGS) employs standard diagrams and Munsell colour samples for the grading of cortical, posterior subcapsular and nuclear cataract. The Lens Opacities Classification System III (LOCS III) uses photographic transparencies of the lens as standards. In both systems a decimalised score is assigned. We also graded the LOCS III standard images using the OCCCGS. Interobserver variation was calculated for both grading systems. Linear calibration lines are plotted for each type of lens opacity. RESULTS: The relationship between LOCS III and OCCCGS for nuclear cataract and posterior subcapsular cataract is linear. The relationship for cortical cataract is linear once the LOCS III scores are squared. The intervals between the LOCS III images when ranked by the human eye using the OCCCGS are linear. Interobserver variation for both systems is good. CONCLUSIONS: The linear calibration lines may be used to convert from one system to another and will be useful in comparing studies or performing meta-analysis. These results show that data from cataract studies using different clinical grading schemes can be compared.

Aged↗
PubMed1997

Prevalence of lenticular abnormalities in a population-based study: Oxford Clinical Cataract Grading in the Melton Eye Study.

PURPOSE: To describe the distribution of the 11 features assessed by the Oxford Clinical Cataract Classification and Grading System (OCCCGS) in a population-based study. METHODS: The Melton Eye Study is an English community-based epidemiological study of the natural history of eye disease in people aged 55 to 74 years. Both lenses of 560 subjects were graded at the slit lamp using a decimalised version of the OCCCGS. Subject prevalences were estimated by logistic regression and the extent, when present, against normal errors regression. RESULTS: White nuclear scatter (WNS), brunescence, cortical spoke (CS), anterior subcapsular opacity (ASC), fibre folds (FF), waterclefts (WC) and perinuclear retro-dots all increased with age (p < 0.05). Posterior subcapsular opacity (PSC), vacuoles, focal dots (FD) and coronary flakes (CF) did not significantly increase with age. Subject prevalences of the features and the mean Oxford scores when present were: WNS (1.33), brunescence (0.88), CS 36% (0.34), PSC 11% (0.52), ASC 2% (0.53), FF 18% (0.53), WC 17% (0.29), retro-dots 11% (1.15), vacuoles 59% (0.43), FD 98% (1.79) and CF 39% (1.24). Significantly more common in women were both coronary flakes (p < 0.001) and waterclefts (p < 0.05). CONCLUSIONS: These are the first data on the distribution of these minor lesions in a population-based study. Coronary flakes and waterclefts are more common in women.

Aged↗
PubMed2000

Attributable risk estimates for cataract to prioritize medical and public health action.

PURPOSE: Cataract is the most common cause of blindness in the world. The purpose of this study was to estimate the population attributable risk associated with identified risk factors for cortical, nuclear, and posterior subcapsular (PSC) cataract in a representative sample of the Victorian population aged 40 years and older. METHODS: Cluster, stratified sampling was used and participants were recruited through a household census. At locally established test sites, standardized clinical examinations were performed to assess cataract and personal interviews were conducted to quantify potential risk factors. Multivariate logistic regression was used to determine the independent risk factors associated with the three types of cataract, and the population attributable risk was calculated. RESULTS: A total of 3271 (83% of eligible) of the urban residents and 1473 (92%) rural residents participated. The urban residents ranged in age from 40 to 98 years (mean, 59 years), and 1511 (46%) were men. The rural residents ranged in age from 40 to 103 years (mean, 60 years), and 701 (48%) were men. The overall prevalence of cortical cataract was 12.1% (95% CL 10.5, 13.8), nuclear cataract 12.6% (95% CL 9.61, 15.7), and PSC cataract 4.93% (95% CL 3.68, 6.17). Significant risk factors for cortical cataract included age, female gender, diabetes for greater than 5 years, gout for greater than 20 years, arthritis, myopia, average annual ocular UV-B exposure, and family history of cataract (parents or siblings). Significant risk factors for nuclear cataract included age, female gender, rural residence, age-related maculopathy, diabetes for greater than 5 years, smoker for greater than 30 years, and myopia. The significant risk factors for PSC cataract were age, rural residence, thiazide diuretic use, and myopia. Of the modifiable risk factors, ocular UV-B exposure explains 10% of the cortical cataract in the community, and cigarette smoking accounts for 17% of the nuclear cataract. CONCLUSIONS: Because of the near universal exposure to UV-B in the environment, ocular protection has one of the highest modifiable attributable risks for cortical cataract and would therefore be an ideal target for public health intervention. Quit smoking campaigns can be expanded to incorporate information about the excess cataract in the community associated with long-term smoking. Nonmodifiable risk factors such as age, gender, and long-term medication use have implications for the timely referral and treatment for those at higher risk of cataract.

Adult↗
PubMedDate not supplied

[Histological characteristics of ocular structures after YAG-laser exposure of various sections of the crystalline lens in experimental studies].

This work was aimed at analysis of all the aspects, pathomorphologic included, of short-pulsed YAG laser exposure of the lens. Experiments were carried out with 79 rabbit eyes. After laser exposure the eyes were enucleated in 1-24 h and in 7-10 days. Thirty-one eyes were subjected to YAG laser ++capsule puncture. Fragmentation of intracapsular structures was carried out in 23 eyes. Combined operations were performed on 25 eyes. Every series comprised two groups, differing by the energy of laser exposure: 3-5 mJ. Histologic analysis has lead the authors to the following conclusions. The pattern and severity of pathomorphologic changes were directly related to the energy and time of laser exposure and site of the focal plane of irradiation. The major destructive shifts after YAG laser fragmentation of the cortical layer and capsulotomy are focussed at the site of exposure and involve the adjacent sections of the lens. Laser exposure of 3-5 mJ may be used to open the anterior capsule of the lens and to facilitate the cataract mass discharge in extracapsular cataract extraction. Use of combined method helps enhance induration and fragmentation of the cortical layers of the lens, rules out surgical discission of the anterior capsule of the lens, and facilitates removal of the nucleus and wash out of the lens mass.

Aluminum↗
PubMed1991

Risk factors for age-related cortical, nuclear, and posterior subcapsular cataracts. The Italian-American Cataract Study Group.

A total of 1,008 cases and 469 controls, aged 45-79 years, were included in a clinic-based case-control study of age-related cataract in Parma, Italy, from 1987 to 1989. Associations were examined between specific types of cataract and physiologic, behavioral, environmental, and biochemical factors. Cases included subjects with pure cortical (n = 489), pure nuclear (n = 110), pure posterior subcapsular (n = 28), and mixed (n = 381) cataracts. With polychotomous logistic regression, an increased risk of cataract was found for females (cortical; odds ratio (OR) = 2.20) and persons with less than a high school education (all types; OR = 1.53), brown irises (nuclear, mixed; OR = 1.43), job locations in the sunlight (cortical, mixed; OR = 1.75), leisure time activities in the sunlight (cortical, mixed; OR = 1.45), a history of wearing a hat in summertime (posterior subcapsular, cortical, mixed; OR = 1.80), a positive family history of cataract (posterior subcapsular, cortical, mixed; OR = 1.88), a history of cortisone use (posterior subcapsular; OR = 8.39), increased red blood cell glucose-6-phosphate dehydrogenase activity (cortical, nuclear, mixed; OR = 1.36), and increased serum levels of uric acid (posterior subcapsular; OR = 1.62), lactic dehydrogenase (posterior subcapsular; OR = 1.76) and gamma-glutamyl transpeptidase (mixed; OR = 1.22). A decreased risk of cataract was found for persons with a positive history of arthritis (posterior subcapsular, nuclear, mixed; OR = 0.56) and increased handgrip strength (mixed; OR = 0.68). Findings from our study, combined with previously reported evidence, suggest that associations with educational status, cortisone use, sunlight exposure, and handgrip strength are real. Other findings require further evaluation.

Adult↗
PubMedDate not supplied

[Absence of small-angle maximums on the x-ray images of ocular lens tissue].

X-ray small-angle scattering study of bovine lens tissue was carried out. It was shown that X-ray patterns of lens cortical and nuclear native tissues did not contain the small-angle maxima. The maximum in the range of 15-20 nm Bragg distance appeared as a result of the lens tissue partial dehydration. Earlier such maximum was considered by some authors as the evidence of crystallin proteins short-range order in the native lens. Now it is confirmed to be a preparative artefact of dehydration. It was shown also that similar maximum in 15-20 range existed in the case of concentrated crystallin solutions. This indicates that supramolecular organization of crystallins in the native lens is not similar to that in the concentrated solution.

Animals↗
PubMed1984

[Distribution of calmodulin in bovine lens; changes as a function of age].

Calmodulin contents were determined by radioimmunoassay in Bovine lens layers as a function of age. The values in the epithelial cell layer appeared to be strikingly higher than in the cortical layer where they were still higher than in the nucleus. In the lens epithelial cell layer the calmodulin levels were maintained when calf was compared with adult or aged animals (100-110 ng/mg protein). Nevertheless, a decrease of calmodulin content was observed in the lens epithelium of very old animals (65 ng/mg prot.). In the cortical layer, the calmodulin content was very low and variable during aging (11-18 ng/mg prot.). In the lens nucleus the extremely low amount of calmodulin still decreased during aging (10-0.2 ng/mg prot.). The significance of these data was discussed.

Aging↗
PubMed1982

Cataracts in the exfoliation syndrome (fibrillopathia epitheliocapsularis).

The histopathological features of the lenticular part of the exfoliation syndrome includes active production of pathological capsular substance in the epithelial cells in the zona germinativa. Analysis of the cataract pattern of 431 exfoliation lenses and 1776 control lenses extracted at the Massachusetts Eye and Ear Infirmary shows a significant difference. Cortical and supranuclear cataract is less common and severe in the exfoliation syndrome, while the reverse is true for nuclear cataract. Posterior subcapsular cataract shows no difference while the anterior variety is slightly more common in the control group. It is suggested that the high level of epithelial metabolic activity may be beneficial for the ionpumps and electrolyte environment of the cortical fibres.

Basement Membrane↗