Intraoperative quantitative crystalline lens nuclear opacities analysis based on crystalline lenSx platform

PURPOSE

The main objective is to quantify the lens nuclear opacity using spectral-domain optical coherence tomography (SD-OCT) and to evaluate its association with Lens Opacities Classification System III (LOCS-III) system, lens thickness (LT), and surgical parameters. The secondary objective is to assess the diagnostic model performance for hard nuclear cataract.

METHODS

This study included 70 eyes of 57 adults with cataract, with 49 (70%) and 21 (30%) in training and validation cohort, respectively. Correlations of the average nuclear density (AND) /maximum nuclear density (MND) with LOCS-III scores, LT, and surgical parameters were analyzed. Univariate and multivariate logistic regression analysis, receiver operating characteristic curves and calibration curves were performed for the diagnostic of hard nuclear cataract.

RESULTS

The pre-operative uncorrected distance visual acuity (UDVA), intraocular pressure (IOP), mean axial length (AL), and LT were 1.20 ± 0.47 log MAR, 15.50 ± 2.87 mmHg, 27.34 ± 3.77 mm and 4.32 ± 0.45 mm, respectively. The average nuclear opalescence (NO) and nuclear colour (NC) scores were 3.61 ± 0.94 and 3.50 ± 0.91 (ranging from 1.00 to 6.90), respectively. The average AND and MND were 137.94 ± 17.01 and 230.01 ± 8.91, respectively. NC and NO scores both significantly correlated with the AND (rNC = 0.733, p = 0.000; rNO = 0.755, p = 0.000) and MND (rNC = 0.643, p = 0.000; rNO = 0.634, p = 0.000). In the training cohort, the area under the curve (AUC) of the model was 0.769 (P < 0.001, 95%CI 0.620-0.919), which had a good degree of differentiation (Fig. 2a). The calibration curve showed good agreement between predicted and actual probability.

CONCLUSION

The nuclear density measurement on SD-OCT images can serve as an objective and reliable indicator for quantifying nuclear density.

Acceleration of age-induced proteolysis in the guinea pig lens nucleus by in vivo exposure to hyperbaric oxygen: A mass spectrometry analysis

Hyperbaric oxygen (HBO) treatment of animals or ocular lenses in culture recapitulates many molecular changes observed in human age-related nuclear cataract. The guinea pig HBO model has been one of the best examples of such treatment leading to dose-dependent development of lens nuclear opacities. In this study, complimentary mass spectrometry methods were employed to examine protein truncation after HBO treatment of aged guinea pigs. Quantitative liquid chromatography-mass spectrometry (LC-MS) analysis of the membrane fraction of guinea pig lenses showed statistically significant increases in aquaporin-0 (AQP0) C-terminal truncation, consistent with previous reports of accelerated loss of membrane and cytoskeletal proteins. In addition, imaging mass spectrometry (IMS) analysis spatially mapped the acceleration of age-related αA-crystallin truncation in the lens nucleus. The truncation sites in αA-crystallin closely match those observed in human lenses with age. Taken together, our results suggest that HBO accelerates the normal lens aging process and leads to nuclear cataract.

Comparison of Perioperative Parameters in Femtosecond Laser-Assisted Cataract Surgery Using 3 Nuclear Fragmentation Patterns

PURPOSE

The purpose of this study was to compare the perioperative parameters of quadrant, sextant, and grid lens fragmentation patterns in femtosecond laser-assisted cataract surgery (FLACS).

DESIGN

Prospective randomized clinical trial.

METHODS

Setting: Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.

STUDY POPULATION

A total of 894 eyes in 661 patients with cataracts were enrolled. Intervention or observation procedures: the nuclear density was graded according to the Emery-Little classification. Patients received lens fragmentation using a quadrant, sextant, or grid pattern after random allocation. Evaluations included intraoperative parameters, complications, and postoperative outcomes.

MAIN OUTCOME MEASUREMENTS

effective phacoemulsification time (EPT), intraoperative complications, visual acuity and intraocular pressure at one day postoperatively, as well as endothelial cell density, endothelial cell loss, and central corneal thickness at 1 week postoperatively.

RESULTS

In grade 1 nuclei, the mean EPT in the grid group was the shortest compared to those in the quadrant (P = 0.011) and sextant (P = 0.001) groups. In grade 2 nuclei, all 3 patterns showed no significant differences in the mean EPT (P > 0.05). In grade 3 nuclei, the sextant group revealed shorter mean EPT than the grid (P = 0.017) and quadrant (P > 0.05) groups. In grades 4 and 5 nuclei, the quadrant pattern had the shortest mean EPT among all 3 patterns (P < 0.05). The grid pattern is associated with higher intraocular pressure in hard nuclei (grades 4 and 5) than the other 2 patterns (P < 0.05).

CONCLUSIONS

The grid and quadrant patterns allow for shorter EPT in soft (grade 1) and hard (grades 4 and 5) nuclei, respectively. All 3 patterns can be selected for treating grade 2 nuclei. The sextant pattern may be the best option when treating grade 3 nuclei. The grid pattern should be avoided in hard nuclei combined with glaucoma or glaucoma suspect.

Granular Dystrophy Associated with Congenital Cataracts

Seven members of the same family suffering from Groenow I granular dystrophy and associated congenital cataracts have been studied. Three patients had corneal dystrophy at various stages and three others had a fetal nuclear congenital cataract. A penetrating keratoplasty button was studied under light and electron microscopies. This association has not been described previously. However we must emphasize that there is no general validity for a correlation between granular dystrophy and congenital cataract.

Objective Assessment of Nuclear and Cortical Cataracts through Scheimpflug Images: Agreement with the LOCS III Scale

PURPOSE

To assess nuclear and cortical opacities through the objective analysis of Scheimpflug images, and to check the correlation with the Lens Opacity Classification System III (LOCS III).

METHODS

Nuclear and cortical opacities were graded according to the LOCS III rules after pupil dilation. The maximum and average pixel intensity values along an elliptical mask within the lens nucleus were taken to analyse nuclear cataracts. A new metric based on the percentage of opaque pixels within a region of interest was used to analyse cortical cataracts. The percentage of opaque pixels was also calculated for half, third and quarter areas from the region of interest's periphery.

RESULTS

The maximum and average intensity values along the nucleus were directly proportional to the LOCS III grade: The larger the LOCS III value, the larger maximum and average intensity ones. These metrics showed a positive and significant correlation with the LOCS grade: The larger the LOCS grade, the higher was percentage of opaque pixels along the cortex within the same mask's size. This metric showed a significant correlation to the LOCS grade.

CONCLUSION

The metrics used to assess nuclear opacities showed good correlation with the LOCS III. The percentage of opaque pixels showed to be a useful metric to measure objectively the severity of the cortical opacity. These metrics could be implemented in an algorithm to detect and grade lens opacities automatically and objectively.

Longitudinal Study of Age-Related Cataract Using Dynamic Light Scattering: Loss of α-Crystallin Leads to Nuclear Cataract Development

PURPOSE

To conduct a longitudinal study on age-related nuclear cataracts using dynamic light scattering (DLS) to determine if cataract progression is associated with loss of the unbound form of the lens molecular chaperone protein, α-crystallin.

DESIGN

Natural history and cohort study.

PARTICIPANTS

Patients 30 years of age or older of either gender seeking treatment at the Wilmer Eye Institute Cornea-Cataract Department.

METHODS

All patients underwent a comprehensive dilated eye examination every 6 months, including slit-lamp grading of their lenses using the Age-Related Eye Disease Study (AREDS) clinical lens grading system and obtaining an estimate of unbound α-crystallin level in the nucleus, the α-crystallin index (ACI), using the National Aeronautics and Space Administration-National Eye Institute DLS device. We used a random effects statistical model to examine the relationship of lens opacity changes over time with ACI changes.

MAIN OUTCOME MEASURES

α-Crystallin Index (ACI) and AREDS nuclear cataract grade.

RESULTS

Forty-five patients (66 eyes) 34 to 79 years of age with AREDS nuclear lens grades of 0 to 3.0 were followed up every 6 months for a mean of 19 months (range, 6-36 months). We found that lenses with the lowest baseline levels of ACI had the most rapid progression of cataracts, whereas lenses with higher ACI at baseline had no or slower cataract progression. Lenses that lost α-crystallin at the highest rates during the study also had faster progression of nuclear cataracts than lenses with a slower rate of ACI loss. Kaplan-Meier survival curves showed that lenses with the lowest initial ACI had the highest risk of undergoing cataract surgery.

CONCLUSIONS

This longitudinal study corroborates our previous cross-sectional study finding that higher levels of unbound α-crystallin as assessed by ACI are associated with lower risk of cataract formation and that loss of ACI over time is associated with cataract formation and progression. This study suggested that assessment of ACI with the DLS device could be used as a surrogate for lens opacity risk in clinical studies, and for assessing nuclear cataract events in studies where cataract development may be a side effect of a drug or device.

Refractive changes in nuclear, cortical and posterior subcapsular cataracts. effect of the type and grade

PURPOSE

To determine the effect of main morphological types and grades of age-related cataracts on refractive error.

METHODS

We measured 276 subjects with optical compensation prior to the development of cataract. We evaluated 224 eyes with nuclear cataract, 125 with cortical cataract, and 103 with posterior subcapsular (PSC) cataract classified with LOCSIII. We measured visual acuity (VA) with their spectacles and best-corrected visual acuity (BCVA) with chart in decimal scale to obtain the optimal compensation with cataract. We evaluated the differences between compensations.

RESULTS

A significant myopic shift was observed in nuclear cataract from low to mild grade (p=0.031), the same as for PSC cataract from mild to advanced grade (p=0.025). No significant changes were found for cortical cataract (p=0.462). Regarding astigmatism, we observed power changes in cortical cataract from low to mild grade (p=0.03) and axis changes in PSC from low to mild grade (p=0.02) and in nuclear cataract from mild to advanced grade (p=0.02).

CONCLUSIONS

Cataract produces changes in patient's compensation which depend on severity and type of cataract. For nuclear and PSC cataract, we observed that the higher the grade of severity, the greater the myopic shift. Power astigmatic changes were found in cortical cataract and axis changes in PSC and nuclear cataract.

[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.

Trench, lollipop, lift and chop technique for mild to moderate cataracts

No abstract available.DOI: http://dx.doi.org/10.3126/nepjoph.v4i2.6561 Nepal J Ophthalmol 2012; 4 (2): 344-345  

Morphologic changes in the anterior chamber in patients with cortical or nuclear age-related cataract

PURPOSE

To assess and compare the morphologic changes in the anterior segment in eyes with nuclear or cortical age-related cataract using Scheimpflug imaging.

SETTING

Peking University People's Hospital, Beijing, China.

DESIGN

Case-control study.

METHODS

Patients with nuclear or cortical age-related cataract were recruited. The grade of nuclear opalescence or cortical opacity was assessed using the Lens Opacities Classification System III (LOCS III). A group of elderly subjects with a clear lens and normal vision served as the control group. Anterior chamber depth (ACD), anterior chamber volume (ACV), and lens thickness were evaluated using Scheimpflug imaging (Pentacam).

RESULTS

Two hundred sixty-nine patients (330 eyes) were recruited. Thirty eyes were enrolled for each nuclear opalescence and cortical grade. The control group comprised 30 eyes (19 subjects). In eyes with age-related cataract, lens thickness increased with an increase in cortical opacity, whereas the ACD and ACV values decreased. The ACD was inversely correlated with LOCS III grades for nuclear opalescence (r = -0.197, P = .004), nuclear color (r = -0.195, P = .005), and cortical opacity (r = -0.508, P<.005). There were significant differences in lens thickness, ACD, and ACV between nuclear color, nuclear opalescence, and cortical opacity for LOCS III grades 3, 4, and 5, respectively.

CONCLUSIONS

There were significant differences in lens thickness, ACD, and ACV between nuclear and cortical age-related cataracts. The ACD decreased more in eyes with cortical cataract, suggesting that the risk for angle-closure glaucoma may be greater in cases of cortical opacity in which lens expansion is greater.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

A computer assisted method for nuclear cataract grading from slit-lamp images using ranking

In clinical diagnosis, a grade indicating the severity of nuclear cataract is often manually assigned by a trained ophthalmologist to a patient after comparing the lens' opacity severity in his/her slit-lamp images with a set of standard photos. This grading scheme is often subjective and time-consuming. In this paper, a novel computer-aided diagnosis method via ranking is proposed to facilitate nuclear cataract grading following conventional clinical decision-making process. The grade of nuclear cataract in a slit-lamp image is predicted using its neighboring labeled images in a ranked image list, which is achieved using a learned ranking function. This ranking function is learned via direct optimization on a newly proposed approximation to a ranking evaluation measure. Our proposed method has been evaluated by a large dataset composed of 1000 different cases, which are collected from an ongoing clinical population-based study. Both experimental results and comparison with several existing methods demonstrate the benefit of grading via ranking by our proposed method.

Ischemic diabetic retinopathy may protect against nuclear sclerotic cataract

PURPOSE

To determine whether diabetes mellitus is protective for nuclear sclerotic cataract at baseline and 6 and 12 months after vitrectomy surgery.

DESIGN

Prospective, interventional cohort study.

METHODS

Phakic diabetic and nondiabetic patients undergoing vitrectomy surgery for a variety of retinal conditions underwent Scheimpflug lens photography in the operated and fellow eye at baseline and at 6 and 12 months after vitrectomy surgery.

RESULTS

Of 52 eyes included in the analysis, 23 eyes were from diabetic patients, 14 of which had surgery for ischemic retinopathy. At baseline, eyes with ischemic diabetic retinopathy had less nuclear sclerotic cataract than nonischemic diabetic and nondiabetic eyes. This was true for eyes undergoing vitrectomy surgery (P = .0001) and for fellow eyes (P = .003). Nuclear sclerotic cataract developed after vitrectomy surgery in nonischemic diabetic eyes and nondiabetic eyes at the same rate. Diabetic eyes with ischemic retinopathy showed no significant progression of nuclear opacification, and therefore had significantly less postvitrectomy nuclear cataract at 6 months (P < 1 × 10(-6)) and at 12 months (P < .001) than nondiabetic or nonischemic diabetic eyes. Normalizing to baseline opacity and adjusting for age and other comorbidities did not alter this result.

CONCLUSIONS

Ischemic diabetic retinopathy, not just systemic diabetes mellitus, protected against nuclear sclerotic cataract at baseline and after vitrectomy surgery. These findings are consistent with the hypothesis that increased exposure to oxygen is responsible for nuclear cataract formation.

Dietary carbohydrate in relation to cortical and nuclear lens opacities in the melbourne visual impairment project

PURPOSE

In vitro and in vivo animal studies suggest that dietary carbohydrates play a role in cataractogenesis. Few epidemiologic studies have been conducted to evaluate this association. The objective of this study was to examine the cross-sectional associations between total carbohydrate intake, dietary glycemic index (dGI), and the risk of cortical and nuclear cataracts.

METHODS

After excluding 864 persons from 2473 eligible participants, 1609 eligible nondiabetic participants (mean age, 57.6 years, 55.9% female) in the Melbourne Visual Impairment Project (VIP) were enrolled. Dietary information derived from a semiquantitative food-frequency questionnaire and cataract status graded by the Wilmer protocol (cortical cataract: opacity >or=4/16; nuclear cataract grade >or=2) were collected. With the use of the generalized estimating approach to logistic regression to account for the lack of independence between the eyes of an individual, the associations between dietary carbohydrates and risk of cataract in eyes with no or a single type (pure) of cataract were examined.

RESULTS

Multivariate adjustment showed that pure cortical cataract (197 eyes) was significantly associated with total carbohydrate intake (odds ratio [OR] comparing the highest quartile with the lowest quartile = 3.19, 95% confidence interval [CI] = 1.10-9.27; P(trend) = 0.017). The OR for nuclear cataract (366 eyes) comparing the third quartile of dGI with the first quartile (OR = 1.64, 95% CI = 1.02-2.65) was significant, but there was not a consistent dose-response association (P(trend) = 0.75).

CONCLUSIONS

Carbohydrate intake may be optimized to prolong eye lens function. Because of the high proportion of subjects with missing covariates, these results warrant further study.

Four-year incidence and progression of lens opacities: the Los Angeles Latino Eye Study

PURPOSE

To estimate the 4-year incidence and progression of lens opacities.

DESIGN

Population-based longitudinal study.

METHODS

A total of 4658 adult Latinos from Los Angeles County were examined at baseline and 4-year follow-up. Examination included assessment of lens opacities using the Lens Opacities Classification System II (LOCS II). Incidences of cortical, nuclear, and posterior subcapsular opacities (with LOCS II scores >or=2) were defined as opacity development in persons without that opacity at baseline. Single and mixed opacities were defined in persons without any opacity at baseline. Incidence of all lens changes included development of at least 1 opacity or cataract surgery among those without any opacity at baseline. Four-year progressions were defined as increase of >or=2 in LOCS II score.

RESULTS

The 4-year incidence of all lens opacities was 14.2%. Four-year incidence of cataract surgery was 1.48%. The incidences were 4.1% for cortical-only, 5.8% for nuclear-only, 0.5% for PSC-only, and 2.5% for mixed. The incidences for any opacities were 7.5% for cortical, 10.2% for nuclear, and 2.5% for PSC. Incidence increased with age (P < .0001 for all). The progressions were 8.5% for cortical, 3.7% for nuclear, and 2.9% for PSC opacities.

CONCLUSIONS

Our Latino population had a higher incidence of nuclear than cortical opacities, but a greater progression of cortical than nuclear opacities. Incidence and progression of PSC was low. Additional understanding of the natural history and progression of various lens opacities will give us a better understanding of the pathogenesis and management of lens opacities.

Moderate alcoholic beverage intake and early nuclear and cortical lens opacities

PURPOSE

To study the relationship between alcoholic beverage intake and early lens opacities.

METHODS

556 Boston-area women aged 53-74 years were sampled from the Nurses' Health Study cohort. Degree of opacity was assessed by eye examinations including lens photography.

RESULTS

After multivariate adjustment, the odds of a nuclear opacity grade > or =2.3 increased by 30% (OR=1.3, 95% CI: 1.10-1.54) per 10-g increase in total alcohol intake. Furthermore, after control for intake of other alcoholic beverages, the odds of a higher nuclear opacity grade increased by 13% (OR=1.13, 95% CI: 1.02-1.26) for every two additional hard-alcoholic drinks consumed per week, and by 17% (OR=1.17, 95% CI: 1.03-1.33) for every two additional glasses of wine consumed per week. The odds of a cortical opacity grade > or =0.4 decreased by 12% (OR=0.88, 95% CI: 0.79-0.98) for every two additional glasses of wine consumed per week, but intake of other alcoholic beverages was unrelated to cortical opacity.

CONCLUSIONS

Consumption of alcoholic beverages, particularly hard liquor and wine, was positively related to nuclear opacity. Wine drinking was inversely related to cortical opacity.

Changes in the internal structure of the human crystalline lens with diabetes mellitus type 1 and type 2

PURPOSE

To investigate the effect of diabetes mellitus (DM) type 1 and type 2 on the internal structure of the lens.

DESIGN

Observational cross-sectional study.

PARTICIPANTS AND CONTROLS

One hundred seven patients with DM type 1, 106 patients with DM type 2, and 75 healthy control subjects.

METHODS

Scheimpflug photography was used to image the lens of the right eye of 213 patients with DM and 75 healthy control subjects. The densitogram of the Scheimpflug image was used to indicate the nucleus and the different layers of the cortex of the lens. Lenses with cataract were excluded.

MAIN OUTCOME MEASURES

The size of the nucleus and the different layers of the cortex of the lens.

RESULTS

The nucleus and the different cortical layers of the DM type 1 lenses were significantly thicker compared with those of the control group (P<0.001). A significant association was found between the duration of DM type 1 and both the anterior and posterior cortex, its different layers, and the nucleus (P<0.001). The increase in the anterior and posterior cortex with the duration of DM was comparable with that of the nucleus. No important differences in the internal structure of the lens were found between the patients with DM type 2 and the control group.

CONCLUSIONS

Diabetes mellitus type 1 has a significant effect on the internal structure of the lens. The difference in effect of DM type 1 and type 2 on internal lens structure suggests an essential difference in pathogenesis. Furthermore, the results of the present study may indicate that the increase in the size of the lens with DM type 1 is the result of a generalized swelling of the lens, affecting all its different parts.

Nuclear cataract and myopic shift in refraction

PURPOSE

Nuclear cataract is thought to cause a myopic shift in refraction in older persons. The authors tested this hypothesis by assessing the correlation of nuclear opacity with spherical equivalent refraction (SER) in an older population.

DESIGN

Population-based cross-sectional study.

METHODS

Three thousand six hundred and fifty-four participants aged 49 years or older were examined in the Blue Mountains Eye Study [BMES] (1992 to 1994). Eye examinations included subjective refraction and lens photographs. Nuclear opacity was assessed against four standard slit-lamp lens photographs using the Wisconsin Cataract Grading System. Nuclear cataract was defined as opacity level 4 or higher.

RESULTS

Participants without nuclear cataract had an annual mean hyperopic shift of 0.05 diopters (P < .0001). In persons with nuclear cataract, this hyperopic shift disappeared. A myopic refractive shift occurred only in persons with nuclear opacity levels of 4 or higher.

CONCLUSION

This study documents the contribution of nuclear cataract to the mild myopic shift that neutralizes the age-related hyperopic shift occurring in older persons.

[Measurement of lens density with a Scheimpflug camera in diabetic patients]

OBJECTIVE

To assess if diabetes, in patients without cataracts or diabetic retinopathy, alters the densitometric values of the lens and to what degree this occurs.

METHODS

A total of 93 patients, divided into two groups, were studied: the diabetic patients had a visual acuity equal to or greater than 0.8 and normal eye funduscopy, and the control group consisted of healthy patients of a similar age. Measurements in all patients were made with the Scheimpflug camera and the lens density of the anterior capsule, anterior cortex and nucleus was defined. The values obtained in the two groups were compared by analysis of variance (ANOVA).

RESULTS

All densitometric values were greater in the diabetic patients than in the normal controls. The greatest difference was seen in the values of the anterior capsule, followed by the nucleus and cortex. The differences approached statistical significance (P=0.07) only in the case of the anterior capsule.

CONCLUSIONS

Diabetes increases densitometric values of the anterior capsule and to a lesser degree of the anterior cortex. However, further studies are necessary to verify if this alteration is of significance.

Rapidly progressive idiopathic lenticular astigmatism

A myopic 43-year-old woman with early nuclear sclerotic cataract developed more than 11.0 diopters (D) of astigmatism over a 6-month period. This was found to be lenticular in origin. Phacoemulsification with intraocular lens implantation was performed, resulting in residual astigmatism of 0.75 D. To our knowledge, this is the first case of rapidly progressive lenticular astigmatism in an otherwise healthy eye with early nuclear sclerotic cataract.

Raman spectroscopic evidence for nuclear disulfide in isolated lenses of hyperbaric oxygen-treated guinea pigs

Our laboratory treats guinea pigs with hyperbaric oxygen (HBO) as a model for investigating the formation of nuclear cataract. Previous analyses of lens supernatants using this model have shown an increase in disulfide (-SS-) and loss of sulfhydryl (-SH) in the lens nucleus of O(2)-treated animals. In this paper, we have used the non-invasive technique of Raman spectroscopy to confirm these findings in intact, freshly-excised lenses. Guinea pigs were treated 3 times per week with HBO for a total of 50 (4 months of treatment) or 85 (7 months of treatment) times to induce an increased level of lens nuclear light scattering. Intact lenses were analyzed by Raman spectroscopy using a 514.5 nm laser and collecting the scattered light in a 90 degrees geometry. The laser beam was focused either in the lens nucleus or equatorial cortex. Changes in the levels of -SS- (503 cm(-1)) and -SH (2577 cm(-1)) vibrations were measured. Raman spectra were analyzed by fitting Lorentzian profiles to the observed data in the -SS- and -SH regions. -SS- levels in the O(2)-treated nucleus were found to have increased by a factor of 2.1 (p=0.0001) and 2.5 (p=0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. Based on previous biochemical analyses, the -SS- increase was due mainly to the formation of protein disulfide (PSSP) with contribution also from protein/thiol mixed disulfides, but not from oxidized glutathione. -SH levels in the O(2)-treated nucleus decreased by 13% (p=0.007) and 35% (p=0.001) after 50 and 85 HBO treatments, respectively, compared to age-matched controls. No significant increase in -SS- or loss of -SH was observed in the lens cortex of the O(2)-treated guinea pigs. The Raman spectroscopy results rule out the possibility that artifactual production of -SS- and loss of -SH occurred during homogenization of lenses in previous studies. The data provide additional evidence to support a link between O(2), disulfide-crosslinking of lens crystallins in the nucleus, and nuclear cataract.

An autosomal dominant progressive congenital zonular nuclear cataract linked to chromosome 20p12.2-p11.23

PURPOSE

To map and to identify the causal gene for autosomal dominant congenital cataract (ADCC) in a Chinese family.

METHODS

A four-generation family with a history of progressive congenital cataracts was investigated. Twenty-three members of the family were examined ophthalmologically. Blood samples were collected from twenty-nine family members for genetic linkage analysis. Two-point LOD scores were calculated. Multi-point linkage analysis and haplotype construction were performed to define the optimal cosegregating interval. Direct sequence analysis of the candidate gene, beaded filament structural protein 1, filensin (BFSP1) in the critical region was carried out.

RESULTS

Fifteen family members were affected with autosomal dominant progressive congenital zonular nuclear cataract (ADPCZNC). The maximum two-point LOD Score of 6.02 was obtained for marker D20S904 (theta=0). The cataract locus in this family was mapped to chromosome 20p12.2-p11.23, a 9.34 Mb (16.37 cM) interval between markers D20S186 and D20S912. Although BFSP1 was in this critical region, we found no evidence that the condition in the family was caused by a BFSP1 mutation.

CONCLUSIONS

We have mapped the genetic locus of ADPCZNC to chromosome 20p12.2-p11.23 in an ADCC family. This is the first time ADPCZNC was linked to this region.

Retained Nuclear Fragments in the Anterior Chamber after Phacoemulsification with an Intact Posterior Capsule

OBJECTIVE

To review the clinical features and treatment of patients with retained nuclear fragments in the anterior chamber (AC).

DESIGN

Single-center, retrospective, noncomparative, consecutive case series.

PARTICIPANTS

Sixteen patients with a diagnosis of retained nuclear fragments in the AC.

METHODS

Retrospective review of the medical records at Bascom Palmer Eye Institute in Miami, Florida, to identify all patients with a diagnosis of retained nuclear fragments in the AC after phacoemulsification surgery without rupture of the posterior capsule. Charts were reviewed and patient characteristics, ocular history, clinical findings, treatment (medical and surgical), and visual outcomes were recorded.

MAIN OUTCOME MEASURES

Visual outcome and visual acuity at last follow-up visit.

RESULTS

Most patients presented with corneal edema and anterior segment inflammation. All patients proved refractory to medical management, and surgical extraction of the retained lens fragment was required. Ten patients were myopic or had long axial lengths and/or steep keratometry readings. Three patients underwent penetrating keratoplasty for intractable corneal edema. One patient required a second surgery for fragment removal after a previous unsuccessful attempt at removal. Visual outcomes for the patients without macular disease who had lens fragment removal alone ranged from 20/20 to 20/40. Of the 2 patients without macular disease who underwent penetrating keratoplasty, the visual outcomes were 20/50 and 20/30.

CONCLUSIONS

Retention of nuclear fragments in the AC may occur after phacoemulsification. This complication was associated with myopia in a majority of patients in this series, and we hypothesize that small fragments may hide in the posterior chamber in these larger eyes. Surgical removal was associated with a good visual outcome in patients without macular disease.

Influence of severity of nuclear cataract on optical biometry

PURPOSE

To compare preoperative and postoperative measurements of the axial length (AL) performed with the IOLMaster (Carl Zeiss Meditec) to evaluate the effect of nuclear cataract on the optical biometry.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

In 245 consecutive eyes of 162 patients scheduled for cataract surgery, type and severity of cataract was evaluated using the Lens Opacities Classification System III. Preoperative and postoperative axial length measurements were performed with the IOLMaster. The postoperative readings of AL were corrected for the IOL optic material implanted.

RESULTS

The preoperative AL measurements were 0.07 mm +/- 0.05 (SD) (range -0.18 to 0.11 mm) longer than the postoperative measurements (P<.001). These differences in AL were only weakly correlated (r = -0.28, P = .01) with the nuclear cataract grade, mean 3.5 +/- 0.9.

CONCLUSION

In this study, AL measurements with optical biometry using the IOLMaster were not influenced by the severity of nuclear cataract to a clinically relevant degree. Furthermore, it was found that AL in the phakic eye was overestimated by about 0.07 mm because of a slightly too low value of the group refractive index used for the crystalline lens.

Staining of vitreous with triamcinolone acetonide in retained lens surgery with phacofragmentation

PURPOSE

To evaluate the beneficial effects of triamcinolone-assisted vitrectomy during management of retained nuclei with phacofragmentation.

SETTING

Dokuz Eylul University, Medical Faculty, Ophthalmology Department, and Retina Eye Center, Izmir, Turkey.

METHODS

Twelve eyes of 12 patients were operated on between January 2002 and September 2003. Eleven patients were referred because of nucleus drop during phacoemulsification surgery. Six of these patients had mature white cataracts, and in 5 cases total nucleus luxation into vitreous cavity had occurred. In 1 case, approximately half of the nucleus was luxated. Five of the referred patients had pseudoexfoliation (PEX), 3 of whom also had phacodonesis. All of these patients had luxated nucleus segments of more than half. One patient was referred with an intraocular lens (IOL) implanted in the sulcus region. One patient who was not referred also had PEX, iridodonesis, and phacodonesis; total drop of nucleus had occurred in this case. All patients were treated with pars plana vitrectomy with triamcinolone acetonide staining of the vitreous material and phacofragmentation of the dropped nucleus segments. In 2 cases, transscleral foldable IOL fixation surgery was combined simultaneously. One patient already had an IOL at the time of referral. Nine patients were left aphakic for secondary procedures.

RESULTS

All patients except 1 with subretinal neovascular membrane achieved best corrected visual acuities of equal or better than 0.5. No intraoperative or postoperative retinal complications were observed after 9 to 15 months of follow-up.

CONCLUSION

Staining of the vitreous material with triamcinolone acetonide during vitrectomy and phacofragmentation surgery for luxated nuclei helped in total removal of the vitreous body, thus preventing the aspiration of peripheral vitreous fibrils by the phaco tip, which might induce retinal detachment intraoperatively or postoperatively.

A case-control study on risk factors for nuclear, cortical and posterior subcapsular cataract: The Casteldaccia Eye Study

PURPOSE

To investigate risk factors for nuclear, cortical and posterior subcapsular age-related cataract.

METHODS

A case-control study was carried out on subjects aged 40 years and older, living in Casteldaccia, Sicily. Twenty-seven potential risk factors were investigated. Nuclear, cortical and posterior subcapsular opacities of the lens were classified according to the Lens Opacities Classification System II. Subjects with advanced lens opacities represented the cases, while an identical number of subjects without or with early cataract, matched for sex and age, were recruited as controls from within the same population.

RESULTS

Univariate analysis showed that myopia and iris atrophy were significantly associated with nuclear cataract. Iris atrophy, use of corticosteroids, pseudoexfoliation syndrome and familial occurrence of cataract were positively correlated with cortical cataract. Myopia, iris atrophy, use of corticosteroids and familial occurrence of cataract presented an association with posterior subcapsular cataract. After multivariate analysis, the variables that remained significantly associated were myopia and iris atrophy for nuclear cataract; iris atrophy, pseudoexfoliation syndrome and familial occurrence of cataract for cortical cataract; and myopia, iris atrophy and familial occurrence of cataract for posterior subcapsular cataract.

CONCLUSION

In addition to well known risk factors such as myopia or use of corticosteroids, the Casteldaccia case-control study shows that iris atrophy represents a previously unrecognized risk factor for each of the three types of cataract.

A new congenital nuclear cataract caused by a missense mutation in the gammaD-crystallin gene (CRYGD) in a Chinese family

PURPOSE

To identify genetic defects associated with nuclear golden crystal autosomal dominant congenital cataract (ADCC) in a Chinese pedigree in the north of China.

METHODS

Clinical data were collected and the phenotype of the affected members in this family was recorded by slit lamp photography. Genomic DNA was isolated from peripheral blood. Linkage analyses excluded all known loci except that in 2q33-q35. Mutation analysis of CRYGs was carried by direct sequencing of the PCR products.

RESULTS

Sequencing of the coding regions of CRYGA, CRYGB, CRYGC, and CRYGD showed the presence of a heterozygous C>A transversion at nt109 of the coding sequence (R36S) in exon 2 of CRYGD, which co-segregated with the affected members.

CONCLUSIONS

The R36S mutation in CRYGD identified in this Chinese family caused a nuclear golden crystal cataract phenotype not described before. This finding is an additional indication that there may be phenotypic heterogeneity of cataract, especially in different races.

Illuminated endochopper in the management of posteriorly dislocated lens nucleus

We describe the use of an illuminated endochopper (a prototype instrument produced by DORC International) in the management of a posteriorly dislocated lens nucleus or lens particles. This instrument helps to divide the lens nucleus or its fragments into small pieces and thus reduces time and ultrasound energy.

Nonvitrectomizing vitreous surgery for epiretinal membrane long-term follow-up

PURPOSE

To report the long-term follow-up results of nonvitrectomizing vitreous surgery for idiopathic epiretinal membrane (ERM).

DESIGN

Nonrandomized comparative case series.

PARTICIPANTS

Thirty patients were followed up for at least 5 years after nonvitrectomizing vitreous surgery.

INTERVENTION

Epiretinal membranes were peeled without infusion of balanced salt solution and removal of the vitreous. The data from the fellow eye was the control data.

MAIN OUTCOME MEASURES

We examined the visual acuities (VAs), objective refractions, and slit-lamp and Scheimpflug photographs from the preoperative and the final examinations of both eyes. Quantitative assessment of the progression of nuclear sclerosis was performed by densitometry analysis using Scheimpflug photography. The recurrence rate of ERM was determined.

RESULTS

The follow-up periods ranged from 60 to 102 months (mean+/-standard deviation, 72.2+/-11.0 months). The patient ages ranged from 52 to 76 years (68.8+/-6.3 years). The final VA improved or stabilized within 2 lines in 29 of 30 eyes (96.7%). No unilateral progression of nuclear sclerosis occurred in any cases. The mean preoperative and postoperative refractions without additional surgery were -0.4+/-2.9 diopters (D) and -0.2+/-3.0 D in the operated eyes, respectively, and -0.2+/-2.5 D and 0.1+/-2.4 D, respectively, in the unoperated fellow eyes. The mean differences in the refractive error between both eyes (operated eye data minus fellow eye data) were -0.2+/-0.7 D before surgery and -0.3+/-0.8 D after surgery (P = 0.319, paired t test). The mean preoperative and postoperative nuclear densities in 16 patients were 69+/-14 nuclear density units (NDUs) and 76+/-12 NDUs in the operated eyes and 71+/-14 NDUs and 78+/-14 NDUs in the fellow eyes, respectively. The mean preoperative and postoperative differences in nuclear densities in both eyes were -2+/-2 NDUs and -2+/-5 NDUs, respectively (P = 0.836, paired t test). The ERM recurred in 10 eyes (33%), and 3 eyes underwent conventional vitrectomy combined with cataract surgery.

CONCLUSIONS

Unilateral nuclear sclerosis did not progress for at least 5 years after nonvitrectomizing vitreous surgery. The recurrence rate of ERM appeared to be higher than that after conventional vitreous surgery.

Carbohydrate intake and glycemic index in relation to the odds of early cortical and nuclear lens opacities

BACKGROUND

Animal studies suggest a role for dietary carbohydrate in cataractogenesis. However, few published human studies have evaluated associations between carbohydrate nutrition and lens opacification.

OBJECTIVE

Our objective was to test the hypothesis that long-term carbohydrate intake and dietary glycemic index are associated with the odds of early cortical and nuclear opacities.

DESIGN

Subjects were 417 Boston-area members of the Nurses' Health Study cohort aged 53-73 y. Dietary information was based on an average from 5 semiquantitative food-frequency questionnaires collected over a 14-y period. Opacities were assessed by using the Lens Opacity Classification System III (LOCS III). We used eyes (n = 711) as the unit of analysis and generated odds ratios by using a generalized estimating approach to logistic regression to account for the lack of independence between the 2 eyes of each subject.

RESULTS

After multivariate adjustment, the odds of cortical opacities (LOCS III >/=1.0) among women in the highest tertile of carbohydrate intake (>/=200 g/d) was 2.46 times (95% CI: 1.30, 4.64; P for trend = 0.005) that among women in the lowest tertile (<185 g/d). This association was not affected by adjustment for dietary glycemic index, which was not associated with early cortical opacities. Carbohydrate nutrition was not associated with the odds of nuclear opacities (LOCS III >/=2.5).

CONCLUSIONS

These data suggest that carbohydrate quantity, but not carbohydrate quality, is associated with early cortical opacities, and that neither the quantity nor the quality of dietary carbohydrate affects the risk of nuclear opacities in middle-aged women.

Age-related nuclear cataract—oxidation is the key

Age is by far the biggest risk factor for cataract, and it is sometimes assumed that cataract is simply an amplification of this aging process. This appears not to be the case, since the lens changes associated with aging and cataract are distinct. Oxidation is the hallmark of age-related nuclear (ARN) cataract. Loss of protein sulfhydryl groups, and the oxidation of methionine residues, are progressive and increase as the cataract worsens until >90% of cysteine and half the methionine residues are oxidised in the most advanced form. By contrast, there may be no significant oxidation of proteins in the centre of the lens with advancing age, even past age 80. The key factor in preventing oxidation seems to be the concentration of nuclear glutathione (GSH). Provided that nuclear GSH levels can be maintained above 2 mm, it appears that significant protein oxidation and posttranslational modification by reactive small molecules, such as ascorbate or UV filter degradation products, is not observed. Adequate coupling of the metabolically-active cortex, the source of antioxidants such as GSH, to the quiescent nucleus, is crucial especially since it would appear that the cortex remains viable in old lenses, and even possibly in ARN cataract lenses. Therefore it is vital to understand the reason for the onset of the lens barrier. This barrier, which becomes apparent in middle age, acts to impede the flow of small molecules between the cortex and the nucleus. The barrier, rather than nuclear compaction (which is not observed in human lenses), may contribute to the lowered concentration of GSH in the lens nucleus after middle age. By extending the residence time within the lens centre, the barrier also facilitates the decomposition of intrinsically unstable metabolites and may exacerbate the formation of H(2)O(2) in the nucleus. This hypothesis, which is based on the generation of reactive oxygen species and reactive molecules within the nucleus itself, shifts the focus away from theories for cataract that postulated a primary role for oxidants generated outside of the lens. Unfortunately, due to marked variability in the lenses of different species, there appears at present to be no ideal animal model system for studying human ARN cataract.

Polygenic effects and cigarette smoking account for a portion of the familial aggregation of nuclear sclerosis

Cataract is the most common cause of blindness worldwide. Nuclear cataract, an advanced stage of nuclear sclerosis, is the most common type of age-related cataract. The authors assessed data from 2,089 persons within 620 extended pedigrees who participated in the 1988-1990 Beaver Dam Eye Study in Wisconsin to determine whether the observed familial aggregation of nuclear sclerosis could be explained by inheritance of a major gene. Familial correlations were examined and segregation analyses were performed on nuclear sclerosis measurements adjusted for age, sex, and pack-years of cigarette smoking. There was modest correlation among close family members after adjustment for age, sex, and pack-years of cigarette smoking: 0.084 between parents and offspring, and 0.198 between sibling pairs. Although results do not support involvement of a single major locus in the etiology of nuclear sclerosis, models that allowed for familial correlation, attributable in part to polygenic effects, did provide a better fit to the observed data than models without a polygenic effect. This finding suggests that several genes of modest effect may influence development of nuclear lens opacity, possibly in conjunction with environmental factors. Cigarette smoking was an important covariate in these analyses. Overall, results highlight the complex etiology of nuclear sclerosis.

Detecting Progression of Nuclear Sclerosis by Using Human Grading Versus Semiautomated Computer Grading

PURPOSE

To assess indices of nuclear sclerosis derived from digitized images made from color (slide) photographs.

METHODS

Film-based slit lamp images taken at baseline and at 5- and 10-year follow-up examinations of the Beaver Dam Eye Study cohort were digitized, and optical traces were taken along an axis through the center of the cornea and lens. Four indices of the severity of sclerosis were calculated based on the optical densities. The associations of the original Beaver Dam grades and these indices to age, vision, and change in severity of sclerosis over two subsequent visits were compared.

RESULTS

At baseline photographs, the Spearman correlation between age and severity was 0.65 for the original film-based grading (n = 4518 right eyes) and varied between 0.46 and 0.71 for the measures from digitized images. Correlations of the indices to visual acuity were 0.38 for the film-based grading and ranged from 0.32 to 0.38 for the other indices. The authors assume that nuclear sclerosis does not regress and the percentage of regression is a reflection of error in grading. The percentage of regression and progression of sclerosis over 5- and 10-year intervals was determined for each index. After 5 years, 48.2% progressed and 4.9% regressed, using the Beaver Dam grades; progression occurred in 4.9% to 9.9%, and regression occurred in 4.5% to 7.0% for the other indices. After 10 years, 61.9% progressed and 3.2% regressed using the Beaver Dam grades; progression occurred in 8.0% to 19.7%, and regression occurred in 2.6% to 9.7% for the other indices.

CONCLUSIONS

Semiautomated grading of the digitized images can be used to process thousands of images with little oversight by a trained grader. Indices of sclerosis that closely parallel human grading in their relationships to age and visual acuity can be easily computed. However, the indices appear to identify significantly less progression of nuclear sclerosis than does human grading. Further development to define a useful metric for identifying severity and progression of nuclear sclerosis is needed.

A new locus for autosomal recessive nuclear cataract mapped to chromosome 19q13 in a Pakistani family

PURPOSE

To identify the disease locus of autosomal recessive congenital nuclear cataracts in a consanguineous Pakistani family.

METHODS

A large Pakistani family with multiple individuals affected by autosomal recessive congenital cataracts was ascertained. Patients were examined, blood samples were collected, and DNA was isolated. A genome-wide scan was performed using 382 polymorphic microsatellite markers on genomic DNA from affected and unaffected family members. Two-point lod scores were calculated, and haplotypes were formed by inspection.

RESULTS

In the genome-wide scan, a maximum lod score of 2.89 was obtained for marker D19S414 on 19q13. Fine mapping using D19S931, D19S433, D19S928, D19S225, D19S416, D19S213, D19S425, and D19S220 markers from the Généthon database showed that markers in a 14.3-cM (12.66-Mb) interval flanked by D19S928 and D19S420 cosegregated with the cataract locus. Lack of homozygosity further suggests that the cataract locus may lie in a 7-cM (4.3-Mb) interval flanked by D19S928 proximally and D19S425 distally. On fine mapping, a maximum lod score of 3.09 was obtained with D19S416 at theta = 0.

CONCLUSIONS

Linkage analysis identified a new locus for autosomal recessive congenital nuclear cataracts on chromosome 19q13 in a consanguineous Pakistani family.

[20 rules for hard nucleus phacoemulsification]

The mature cataract with hard nucleus still represents one of the most difficult task for modern phacoemulsification. The author presents some practical advise concerning both less experienced and experienced surgeons.

Chopstick technique for nucleus removal in an impending dropped nucleus

We describe a bimanual chopstick technique for nucleus removal after a posterior capsule tear and an impending dropped nucleus during phacoemulsification. The technique stabilizes the nucleus and nuclear fragments by providing posterior support with a Sinskey hook introduced from the pars plana. Once supported, the nucleus is gripped between 2 instruments, brought out of the capsular bag into the anterior chamber, and then taken out of the enlarged wound. This bimanual removal technique causes minimal disturbance to the vitreous, iris, and cornea.

A novel connexin46 (GJA3) mutation in autosomal dominant congenital nuclear pulverulent cataract

PURPOSE

To report the identification of a novel mutation of connexin46 in a large Chinese family with autosomal dominant congenital nuclear pulverulent cataract.

METHODS

Genetic linkage analysis was performed on the known genetic loci for autosomal dominant congenital nuclear pulverulent cataract with a panel of polymorphic markers and mutations were screened by direct sequencing.

RESULTS

Significant two point lod score was generated at marker D13S175 (Zmax=3.61, theta=0), further linkage and haplotype studies confined the disease locus to 13q11-13. Mutation screening of connexin46 in this family revealed an A->C transition at position 563 (N188T) of the cDNA sequence, creating a novel AleI restriction site that co-segregated with affected members of the pedigree, but was not present in unaffected relatives or 100 normal individuals.

CONCLUSIONS

Our finding expands the spectrum of connexin46 mutations causing autosomal dominant congenital nuclear pulverulent cataract, and confirms the role of connexin46 in the pathogenesis of autosomal dominant congenital nuclear pulverulent cataract.