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PubMed1987

Progressive changes in lens crystallin glycation and high-molecular-weight aggregate formation leading to cataract development in streptozotocin-diabetic rats.

Because of their remarkable longevity, lens crystallins undergo a substantial amount of glycation (non-enzymatic glycosylation) during diabetic hyperglycemia. These post-translational modifications have the potential to disrupt the structural and functional properties of the lens crystallins and contribute to the formation of cataracts. Streptozotocin-induced diabetic rats were used to study the relationship between glycation of lens proteins and the formation of insoluble high-molecular-weight (HMW) aggregates believed to be responsible for cataract formation. After the onset of diabetes, cataracts developed in about 12- to 13 weeks. The animals were followed in this manner until cataracts developed and for an additional 63 days. Five control and five diabetic rats were killed every 3 weeks and lenses removed. Levels of glycated protein and glycated amino acids in lenses from each animal were examined by affinity chromatography. In addition, the changes in crystallin composition and development of HMW aggregates were monitored by molecular-sieve HPLC techniques. As diabetic hyperglycemia continued there was a linear increase in glycated protein in both the soluble and insoluble fractions. This increase was paralleled by an increase in the soluble HMW and insoluble HMW aggregates. Other changes included a decrease in reactive sulfhydryls which indicates an increase in disulfide bond formation. The gamma-crystallin levels also decreased in a linear fashion during the hyperglycemic pre-cataract and cataract stages. It appears that the glycation of lens crystallin, the disappearance of reactive sulfhydryls and the formation of HMW aggregates are interrelated.

Amino Acids↗
PubMed1988

Glycation of cataractous lens in non-diabetic senile subjects and in diabetic patients.

Early- and advanced-stage products in the Maillard reaction, glycation, were measured in patients with diabetic or senile cataracts. Early-stage products were measured by means of furosine, which is an acid-hydrolysis product derived from fructose-lysine. Advanced-stage products were measured by fluorometry using high-performance liquid chromatography. Furosine levels were high (listed in descending order) in capsule, cortex and nucleus in both diabetic and senile cataracts. The advanced-stage products were also high (listed in descending order) in nucleus, cortex and capsule in both diabetic and senile cataracts. These results suggest that advanced-stage products might accumulate in larger amounts in the nucleus and cortex than in the capsule, resulting in the formation of cataracts. The study also revealed that the Maillard reaction plays an important role in causing not only diabetic cataracts but also senile cataracts.

Aged↗
PubMedDate not supplied

Infantile cataracts.

Cataracts are one of the most treatable causes of visual impairment during infancy. Recent epidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases per 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery.

Animals↗
PubMedDate not supplied

Evidence for the participation of alpha B-crystallin in human age-related nuclear cataract.

The aim of this study was to determine if the unusual coloured species characteristic of age-related nuclear cataract could be localised to specific residues of the crystallins. The insoluble, crosslinked and coloured cataract protein fraction (CPF) was isolated from cataract human lenses. Using a combination of tryptic digestion, gel filtration and multiple reversed phase high performance liquid chromatography (RP-HPLC), coloured peaks were isolated and subjected to amino acid sequence analysis. With these techniques, it was hoped to identify and locate the modified residues. Sequence information was obtained on 16 'coloured' peptides. Many of the peptides were found to be derived from alpha B-crystallin. When redundancies are taken into account, six distinctive peptides were found to be derived from alpha B-crystallin; one from beta B1-crystallin, two from beta A3/A1-crystallin and three from gamma S-crystallin. Three sites of possible crystallin residue isomerisation to modification were detected in the alpha B- and beta A3/beta A1-crystallins, including probable asp isomerisation at residues 25 and 36 in alpha B-crystallin. Since the CPF is unique to nuclear cataract lenses, these data suggest that alpha-crystallin, and alpha B-crystallin in particular, may be implicated in the cataract process. This finding supports that of a recent study on cataract proteins using pronase digestion [Chen YC, Reid GE, Simpson RJ, Truscott RJW. Exp Eye Res 1997;65:835.]

Aging↗
PubMed2000

Relative anterior microphthalmos: morphometric analysis and its implications for cataract surgery.

PURPOSE: To evaluate morphometric data and risk factors for complications of cataract surgery in patients with relative anterior microphthalmos (RAM). DESIGN: Retrospective, comparative study (Part I) and matched pairs analysis with controls (Part II). PARTICIPANTS: Sixty-two patients with RAM who underwent cataract surgery at the Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Germany, between 1989 and 1997. RAM is defined as eyes with horizontal corneal diameters </=11 mm, axial length of >20 mm, and no other morphologic malformation. MAIN OUTCOME MEASURES: Part I: Patients were examined preoperatively for anterior chamber (AC) depth, lens thickness, total axial length, and refraction. Associated ocular pathologic conditions (such as glaucoma or previous surgical interventions) were recorded. Part II: A matched pairs analysis concerning the anatomic features was performed with a group of 17 patients with RAM and 17 patients (controls) that matched the RAM group in terms of axial length, age, and gender but showed corneal diameters >11 mm. RESULTS: Part I: Anatomic parameters in RAM showed an average corneal diameter of 10.7 +/- 0.34 mm, AC depth of 2.20 +/- 0.49 mm, and average lens thickness of 5. 05 +/- 0.45 mm. Fifty-five percent of the patients had myopic refraction. There was a high incidence of glaucoma (77.4%), cornea guttata (45.2%), and pseudoexfoliation syndrome (16.1%) in the RAM group. Sixty percent of patients had undergone previous glaucoma surgery. After cataract surgery, 51.2% of patients achieved a visual acuity of >20/40 and 69.8% of >20/50. Temporary corneal edema (54. 8%) and ciliolenticular block (11.6%) were the most important complications after cataract surgery. Part II: Matched pairs analysis showed significant differences between RAM and controls in terms of AC depth (P =0.029) but no difference in lens thickness (P = 0.12). CONCLUSIONS: Relative anterior microphthalmos can be characterized in terms of morphometric data as eyes with corneal diameters </=11 mm and AC depths of 2 mm. The small anterior segment, especially the shallow anterior chamber, is responsible for the high incidence of glaucoma and postoperative complications after cataract surgery. Identifying these patients before surgery helps the cataract surgeon to be prepared for potential problems.

Aged↗
PubMed2001

Plasma antioxidant vitamins and carotenoids and age-related cataract.

OBJECTIVE: To investigate the relationships between plasma concentrations of antioxidant vitamins and carotenoids and nuclear, cortical, and posterior subcapsular cataracts in a group of elderly men and women. DESIGN: Cross-sectional survey. PARTICIPANTS: Three hundred seventy-two men and women, aged 66 to 75 years, born and still living in Sheffield, England. METHODS: The Lens Opacities Classification System (LOCS) III was used to grade nuclear, cortical, and posterior subcapsular lens opacities. Fasting blood samples were taken to assess plasma concentrations of vitamin C, vitamin E, alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin, and beta-cryptoxanthin. MAIN OUTCOME MEASURES: Logistic regression analyses of the associations between plasma vitamin concentrations and cataract subtype, adjusting for age, gender, and other risk factors. RESULTS: After adjustment for age, gender, and other risk factors, risk of nuclear cataract was lowest in people with the highest plasma concentrations of alpha-carotene (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.3-0.9, P for trend 0.006) or beta-carotene (OR, 0.7; 95% CI, 0.4-1.4, P for trend 0.033). Risk of cortical cataract was lowest in people with the highest plasma concentrations of lycopene (OR, 0.4; 95% CI, 0.2-0.8, P for trend 0.003), and risk of posterior subcapsular cataract was lowest in those with higher concentrations of lutein (OR, 0.5; 95% CI, 0.2-1.0, P for trend 0.012). High plasma concentrations of vitamin C, vitamin E, or the carotenoids zeaxanthin and beta-cryptoxanthin were not associated with decreased risk. CONCLUSIONS: These findings suggest that a diet rich in carotenoids may protect against cataract development, but because they are based on observational data, they need to be confirmed in randomized controlled trials.

Aged↗
PubMed1983

Overview of the current attempts toward the medical treatment of cataract.

A variety of agents are currently available that claim to either prevent, delay, or reverse cataracts associated with aging (senile cataracts), radiation, or diabetes and galactosemia (sugar cataracts). Senile cataract therapy includes formulation containing inorganic salts, nutritional supplements, natural product extracts, sulfhydryl, and sulfonic acid containing compounds and miscellaneous redox and nonsteroidal anti-inflammatory compounds. Agents associated with the treatment of radiation cataracts include anti oxidants and free radial scavengers. Aldose reductase inhibitors have been effective in the prevention of sugar cataracts. A summary of these agents and their potential ocular effects are presented.

Aging↗
PubMed1984

Mechanisms of senile cataract formation.

Research on the mechanisms of lens opacification during the past 20 years has revealed a number of individual, identifiable cataractogenic stresses in man. They include osmotic cataract formation (diabetic, galactosemic and hypoglycemic cataracts), radiation cataracts (X-irradiation, near U.V. radiation and microwave radiation) and in senile cataract the conversion of soluble low molecular weight cytoplasmic proteins to soluble high molecular weight aggregates, insoluble phases, and insoluble membrane-protein matrices. Oxidative stress has emerged as a common denominator of many changes in senile cataract. As we increase our understanding of these mechanisms, we may be able to intervene therapeutically to delay or prevent human cataract formation in man.

Aged↗
PubMed1986

Galactokinase activity in patients with idiopathic cataracts.

Ninety-four consecutive patients admitted for elective cataract surgery were prospectively examined for erythrocyte galactokinase activity. The presumed etiology for the cataract was established by history and physical examination in 51 patients (21 were diabetic). The cataract was classified as idiopathic in 43 patients. Galactokinase activity was significantly lower in idiopathic vs. presumed (nondiabetic) etiology patients 50 years of age or younger (P less than 0.05) and in idiopathic cataract patients 50 years of age or younger vs. those older than 51 years of age (P = 0.0033). Three of the idiopathic cataract patients (6.9%) had galactokinase levels less than two standard deviations below the mean galactokinase level for age-matched patients with suspected (nondiabetic) etiology. Compared with the expected distribution for the heterozygote in the general population (0.2%), this was highly significant (P = 0.0001). Diminished galactokinase activity may increase the risk of developing presenile cataracts requiring surgery by the fourth decade.

Adult↗
PubMed1992

Retained intravitreal lens fragments after cataract surgery.

PURPOSE: The purpose of this study is to review the possible benefits and complications of vitrectomy for retained lens fragments after cataract surgery. METHODS: The authors reviewed the charts of 65 patients referred over a 12-year period for retained lens fragments after cataract surgery. Of these, 56 underwent vitrectomy and 9 were followed. Of these 56 eyes, 29 (52%) had received an intraocular lens (IOL) at the time of cataract surgery. RESULTS: Resulting complications from retained lens material included glaucoma (52%), corneal edema (46%), uveitis (56%), and decreased vision (100%). These sequelae responded equally to vitrectomy in eyes with or without an IOL and irrespective of type of cataract surgery (phacoemulsification or extracapsular cataract extraction). The timing of surgery did not statistically influence the final vision or the incidence of glaucoma. CONCLUSION: Removal of retained lens fragments allows rapid visual restoration, enhances resolution of uveitis, and improves control of glaucoma. Insertion of an IOL at the time of cataract surgery in the face of dislocated lens fragments is not contraindicated provided that it could be performed safely.

Adult↗
PubMed1996

Assessment of appropriateness of cataract surgery at ten academic medical centers in 1990.

PURPOSE: To develop criteria for the appropriateness of cataract surgery (extracapsular cataract extraction or phacoemulsification with planned implantation of a posterior chamber intraocular lens) and to apply these criteria to patients from ten academic medical centers. METHODS: The study is a retrospective case series from ten academic medical centers. One thousand one hundred thirty-nine patients who had had cataract surgery in 1990 at the medical centers were selected randomly. Patients, identified by specific ICD-9-CM or CPT-4 codes, had no other ocular surgery performed at the same time as cataract surgery. Rates of inappropriate, uncertain, appropriate, and appropriate and crucial surgeries were determined by application of the criteria established by a multidisciplinary expert panel. RESULTS: Approximately 2% of the procedures were classified as inappropriate, after adjusting for missing or nonspecific visual function by use of discriminant analysis. Ninety-one percent of the procedures were classified as appropriate (52%) or appropriate and crucial (39%). Seven percent were designated as uncertain, either due to a median rating in the uncertain range or to disagreement in ratings among the panelists. Significant variation occurred in the results among the different institutions: inappropriate surgeries ranged from 0% to 4%, uncertain from 1% to 14%, appropriate from 35% to 66%, and appropriate and crucial from 21% to 62% (P=0.02). CONCLUSION: A small percentage of cataract surgeries was performed at these ten academic medical centers for inappropriate indications using the study criteria. Given the large number of cataract surgeries performed annually, the small percentage of uncertain and inappropriate surgeries may translate into a large number of surgeries performed for less than appropriate or appropriate and crucial indications. Significant variation existed among the institutions in the distribution of appropriate and crucial and appropriate compared with uncertain and inappropriate surgeries.

Academic Medical Centers↗
PubMedDate not supplied

Long-term visual results in congenital cataract surgery associated with preoperative nystagmus.

BACKGROUND: Congenital cataracts are the leading cause of preventable blindness in children. The prevalence of this disease is higher in developing countries. The incidence and visual outcome of patients who have undergone congenital cataract surgery in Mexico is not currently known. The purpose of this study is to evaluate the long-term visual results in Mexican children with bilateral congenital cataracts associated with preoperative nystagmus. METHODS: In a tertiary-level hospital, the long-term visual results of 13 children (26 eyes) with bilateral congenital cataracts associated with preoperative nystagmus were evaluated. All patients had at least 5 years of follow-up after surgery, and all patients were subjected to an intentional ophthalmologic examination. Three types of visual function were evaluated: visual acuity, contrast sensitivity vision, and stereoscopic vision. Age at surgery was correlated with visual outcome. Optical rehabilitation and surgical complications were also analyzed. RESULTS: Our group found five patients (38%) with acceptable visual acuity levels. Eight patients (62%) were legally blind according to World Health Organization (WHO) guidelines. Contrast sensitivity vision and stereopsis were severely affected in all patients. We also found a high correlation between timing of surgery, optical rehabilitation, and visual outcome. CONCLUSIONS: Early diagnosis and treatment, in addition to adequate optical rehabilitation, are mandatory for preventing blindness secondary to congenital cataracts in developing countries. The current state of congenital cataract management in Mexico is also examined.

Adolescent↗
PubMed1990

Cataract surgery. Current approaches.

Cataract surgery in the dog can be a highly successful and rewarding technique for restoring vision to the cataract patient. Coexisting ocular conditions can complicate cataract surgery or be a contraindication for lens removal; these include KCS, uveitis, glaucoma, lens subluxation, and retinal disease. Techniques for cataract surgery include intracapsular cataract extraction, extracapsular cataract extraction, and phacofragmentation, both extracapsular and endocapsular (intercapsular). Phacofragmentation is probably the most successful technique in the dog at this time. Postoperative complications include uveitis, hyphema, glaucoma, capsular opacities, corneal endothelial damage, and retinal detachments. Newer methods of dealing with these problems include the use of viscoelastic materials and IOL implants intraoperatively and the use of the Nd:YAG laser for posterior capsulotomies postoperatively.

Animals↗
PubMed2003

The Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract (CTNS): design implications. CTNS report no. 1.

The Italian-American Clinical Trial of Nutritional Supplements and Age-Related Cataract (CTNS) is a 13-year study designed primarily to evaluate the safety and efficacy of a vitamin-mineral supplement containing recommended daily allowance (RDA) dosages in preventing age-related cataract or delaying its progression. As secondary objectives the study will collect data on incidence and progression rates as well as risk factors for the disease. The clinical trial was initiated largely because of epidemiological studies suggesting that various nutrients, particularly those with antioxidant capabilities, might retard cataract development. The possibility of a beneficial effect on cataract and other age-related diseases has contributed to the widespread use of dietary supplements in the United States among the elderly population, even in the absence of definitive evidence about the safety and effectiveness of such use. The low rate of dietary supplement use in the Italian population provided an opportunity for a trial in which the efficacy of RDA dose supplementation could be tested against no supplementation at all. Relevant design issues for the study include defining cataract and cataract progression, estimating event rates, evaluating reproducibility of the lens grading system for different types of opacity, and identifying the criteria for assessing efficacy and safety. This paper describes the CTNS design and rationale and the approach used to address the issues described above.

Age Factors↗
PubMed2000

Phacoemulsification and intraocular lens placement in eyes with cataract and congenital coloboma: visual acuity and complications.

PURPOSE: To evaluate the safety and complications of phacoemulsification in a series of patients with congenital coloboma and cataract. SETTING: University-based hospital practice. METHODS: A retrospective review was conducted of consecutive patients who had coloboma and cataract and had phacoemulsification between January 1987 through December 1998. Complications and visual acuity 2 months postoperatively were assessed. RESULTS: Mean age of 7 cases at the time of surgery was 41.6 years +/- 11.1 (SD). Visual acuity improved in 6 of 7 eyes; 1 eye had no change. Six eyes had no serious complications. In 1 eye, a retinal detachment was observed postoperatively, but there was no loss in visual acuity. Another patient developed postoperative monocular diplopia from exposure of the intraocular lens (IOL) edge within the inferonasally located corectopia associated with the coloboma. Nonsurgical treatment was unsuccessful, but this symptom resolved after surgical pupilloplasty. CONCLUSIONS: The results of this small case series affirm that clinically significant cataract develops at a younger age in eyes with congenital coloboma than in eyes with typical age-related nuclear sclerotic cataract. Monocular diplopia, a potential complication after cataract surgery in these eyes, can be managed by pupilloplasty. The improved vision in this study indicates that phacoemulsification and IOL placement are safe and beneficial in patients with typical congenital coloboma and cataract.

Adolescent↗
PubMed2001

Traumatic wound dehiscence after cataract extraction.

PURPOSE: To study the visual outcome and factors associated with it in patients with traumatic dehiscence of a cataract surgery wound. SETTING: Department of Ophthalmology and the Brown School of Public Health and Community Medicine, The Hebrew University-Hadassah Medical School, Jerusalem, Israel. METHODS: A retrospective observational study of 37 eyes of 37 consecutive patients with traumatic wound dehiscence of a cataract surgery wound was conducted. A complete ophthalmic evaluation was performed in all patients. Statistical analysis was done to identify factors associated with the best corrected visual acuity at the end of follow-up. RESULTS: Patients had extracapsular cataract extraction (n = 29), intracapsular cataract extraction (n = 4), or lensectomy (n = 4). No patient had phacoemulsification via a small incision. A univariate analysis showed that factors associated with a worse visual outcome included the presence at presentation of hyphema (P = .05), intraocular lens dislocation or loss (P = .006), vitreous hemorrhage (P = .0002), scleral rupture (P = .001), a long interval from surgery to trauma (P < .0001), and fall as the cause of trauma (P < .0001). In a multivariate model, only a surgery-to-trauma interval longer than 8 weeks was associated with a worse visual outcome (P < .0001). Visual acuity immediately after trauma was a poor predictor of final visual acuity. CONCLUSIONS: Visual outcome after traumatic wound dehiscence of a cataract surgery wound was strongly associated with the interval from surgery to trauma. Other factors were less reliable predictors of visual outcome. Traumatic wound dehiscence only moderately affected visual outcome after cataract surgery in most cases.

Adolescent↗
PubMed2002

Strategy to reduce the number of patients perceiving impaired visual function after cataract surgery.

PURPOSE: To reduce the number of patients who perceive more difficulties performing daily life activities 6 months after cataract extraction than before surgery. SETTING: Surgeons at 4 surgical units participating in the yearly outcome studies organized by the Swedish National Cataract Register. METHODS: This study comprised surgical outcomes data and completed Catquest results before and after surgery collected from consecutive patients during a 1-month period yearly since 1995. The reasons for a no-benefit outcome from 1995 to 1997 were identified. During the 1-month study period in 1999, a strategy was launched to reduce postoperative anisometropia and disturbances from cataract in the fellow eye through better surgical planning. RESULTS: The percentage of patients with a no-benefit outcome who had anisometropia or cataract in the fellow eye as a probable reason for the outcome decreased from 27.3% and 13.0%, respectively, in the 1995 to 1997 study to 10.5% and 10.5%, respectively, in the 1999 study. Other reasons for a no-benefit outcome such as ocular co-morbidity or few preoperative problems increased in frequency, presumably as a result of a change in case mix. CONCLUSIONS: A strategy to reduce the number of patients perceiving more difficulties in performing daily life activities after cataract extraction than before surgery was tested. The number of patients with reasons for a poor outcome that the study focused on was reduced. Patients who gave reasons for a poor outcome other than anisometropia or cataract in the fellow eye increased in frequency, probably as a result of a change in case mix.

Activities of Daily Living↗
PubMed2003

Nuclear sclerotic cataract in young patients in Taiwan.

PURPOSE: To document the clinical features of discrete nuclear sclerosis in young patients. SETTING: Chang-Gung Memorial Hospital, Taoyuan, Taiwan, Republic of China. METHODS: The medical records of all patients younger than 45 years with nuclear sclerosis who had cataract surgery at 1 hospital were retrospectively reviewed. Patients with congenital cataract, ocular trauma, ocular disease in addition to myopia, and systemic disease associated with cataract were excluded. The patients' age, sex, bilateral lens status, axial length, original and preoperative refractive status, and preoperative and postoperative best corrected visual acuities (BCVAs) were recorded. RESULTS: Fifty-five eyes of 35 patients aged 32 to 45 years met the study criteria. Nuclear sclerotic cataract was bilateral in 20 patients. The mean age at surgery was 40.64 years +/- 3.63 (SD). The mean refraction before the development of cataract was -7.80 +/- 3.57 diopters (D) and the mean preoperative refraction, -17.40 +/- 6.05 D. The mean axial length was 28.09 +/- 2.31 mm. The postoperative BCVA was 20/22 or better in 53 eyes (96.4%). CONCLUSIONS; In patients younger than 45 years with cataract in Taiwan, nuclear sclerosis was not a rare cause of visual loss and axial myopia was strongly associated with the formation of nuclear sclerosis. Bilateral sclerosis was observed in most cases. Patients with an axial length greater than 27.0 mm had the greatest risk. Surgical treatment was therapeutic.

Adult↗