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.

Spontaneous Dislocation of the Lens Nucleus Into the Anterior Chamber Observed in a Patient With Overmature Senile Cataract.

Overmature cataract refers to the advanced stage of cataract where timely surgical intervention is not performed, leading to further progression characterized by decreased water content in the lens, degradation of fibers, and liquefaction within its structure, which can cause a reduction in volume, wrinkling of the capsule, as well as calcification or cholesterol crystallization on its surface. In addition, it may result in deepening of the anterior chamber. If left promptly untreated, these complications may result in visual impairment or even blindness. The occurrence of spontaneous complete dislocation of the lens nucleus into the anterior chamber in overmature cataracts is extremely uncommon. The authors present a case study involving a 74-year-old female patient who was diagnosed with complete dislocation of the lens nucleus in an overmature senile cataract without any apparent ocular injury or any relevant medical records. After undergoing cataract removal combined with anterior vitrectomy, the patient experienced relief from eye discomfort and expressed satisfaction with the surgical outcome; however, her visual acuity did not show significant improvement.

[Optimization of phacoemulsification technique for Morgagnian cataract]. / Optimizatsiya tekhnologii fakoemul'sifikatsii morganievoi katarakty.

PURPOSE: This study was conducted to develop a new optimized phacoemulsification technique for Morgagnian cataract taking into account the anatomical and topographic parameters of the lens nucleus. MATERIAL AND METHODS: A working classification of Morgagnian cataract was developed based on the size of the nucleus: if the edge of the nucleus is visualized at the upper edge of the pupil or between the upper edge and the middle of the pupil, it was classified as an initial stage of Morgagnian cataract with a large nucleus; if the upper edge of the nucleus is visualized in the middle of the pupil and below, it was classified as an advanced stage of Morgagnian cataract with a small nucleus. The first group included six patients who underwent surgery using the scaffold technique with removal of the whole small nucleus into the anterior chamber. The second group included 11 patients who underwent surgery using the scaffold technique with removal of the last fragment of the nucleus into the anterior chamber. RESULTS: The use of the scaffold technique with removal of the nucleus into the anterior chamber helped reduce the number of intraoperative complications to 16.7% in the first group, compared to 27.3% in the second group, and the percentage of endothelial cell loss to 10.1% in the first group, compared to 10.7% in the second group. CONCLUSIONS: The anatomical and topographic features of the lens and the anterior segment of the eye in Morgagnian cataract with a small nucleus allow for preliminary implantation of an intraocular lens into the capsular bag to protect the posterior capsule during phacoemulsification of the nucleus with minimal mechanical, hydrodynamic and acoustic damage to the surrounding structures of the eye.

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.

Analysis of lens epithelium telomere length in age-related cataract.

We aimed to investigate the associations among lens epithelium telomere length (LETL), cataract types, and systemic pro-senescence factors in patients with age-related cataract. In this prospective study, the general demographic factors, body mass index, smoking history, depression, hypertension, diabetes, various psychological measures, and uncorrected distant visual acuity of patients with age-related cataract were recorded. Lens Opacities Classification System III (LOCS III) scores and lens density measured by Scheimpflug imaging were used to evaluate the cataracts. LETL was measured by real-time polymerase chain reaction. Correlations among these parameters were analyzed. The LOCS III nuclear opalescence (NO) score was associated with age (ß = 0.053, P < 0.001) and Patient Health Questionnaire-9 score (ß = -0.042, P = 0.004). Smoking was identified as a risk factor affecting LOCS III NO score (odds ratio = 1.546, 95% confidence interval, 1.128-2.119), but not the LOCS III cortical or posterior subcapsular scores. LETLs showed a weak association with systemic factors and LOCS III scores, and a significantly moderate correlation with the average objective lens densities of different regions measured by Scheimpflug imaging (r values ranged from -0.278 to -0.523, P < 0.05). However, there was no correlation between the LETLs and the maximum lens densities. The groups with a relatively low lens density had longer LETLs. In Conclusion, being an age-related disease, cortical cataract was also associated with "aging of the lens epithelium." Notably, lens epithelium activity rarely showed systemic effects. Thus, future studies should emphasize the importance of the telomeric system in cataractous process and aging.

Comparison of power-free-chop and phaco-chop techniques for moderate nuclei.

BACKGROUND: To compare the intraoperative and postoperative effects of power-free-chop and phaco-chop techniques for moderate nuclei in phacoemulsification surgery. METHODS: Sixty patients were evaluated in 2 groups. The power-free-chop technique was performed in Group 1 (30 eyes), and the phaco-chop technique was performed in Group 2 (30 eyes). There were no significant differences between these 2 groups. The cumulative dissipated energy (CDE), time to achieve maximum vision, corneal thickness variation, and time to return to the preoperative values were collected. All parameters were statistically compared in these 2 groups by using the chi-square test and the independent-sample t-test. RESULTS: The CDE was 5.53 ± 1.92 J in Group 1 and 7.02 ± 1.77 J in Group 2. After the operation, the mean time to recover to the maximum vision was 2.80 ± 1.42 days in Group 1 and 3.80 ± 1.92 days in Group 2. The mean postoperative corneal thickness increased 36.9 ± 14.74 µm in Group 1 and 46.20 ± 20.67 µm in Group 2. The mean time to return to preoperative pachymetry values was 3.73 ± 1.70 days and 4.83 ± 2.11 days in Group 1 and Group 2, respectively. There were significant differences in these parameters between the groups. CONCLUSIONS: The power-free-chop technique had fewer negative effects on the corneal endothelium, as less ultrasound power was used for moderate nucleus cases. This can accelerate the functional healing process and the return to preoperative physiologic values.

Spontaneous full thickness macular hole development and closure in a patient with nucleus dislocation due to hypermature cataract: a case report.

Spontaneous posterior capsule rupture with lens-nucleus dislocation is a very rare entity, as is the development and spontaneous closure of a full thickness macular hole (FTMH) after vitrectomy. The occurrence of these two entities in one eye has not been previously described. A 79-year-old woman was referred because of the right eye intermittent pain and progressive visual loss. Best corrected visual acuity (BCVA) with correction for aphakia was 20/20. Intraocular pressure was normal with therapy. The cornea, anterior chamber, and vitreous were clear. Gonioscopy was normal. The capsular bag was clear, with rolled-up anterior and posterior lens capsule, and the nucleus dislocated in the vitreous. As surgery waiting time was prolonged due to administrative problems, the patient's intraocular pressure (IOP) increased and cystoid macular edema (CME) with lamellar macular hole developed. The patient underwent pars plana vitrectomy with endophacofragmentation and epiretinal membrane peeling. Postoperative optical coherence tomography was normal, BCVA was 20/40, and IOP was normal with topical therapy. One month after surgery, the eye was without signs of inflammation and IOP started rising in spite of maximum therapy. CME reoccurred and progressed to a FTMH, which started closing spontaneously in one month. One year after surgery, IOP normalized and FTMH closed completely. A dislocated crystalline lens in a quiet eye with normal BCVA, which rapidly developed into intractable glaucoma and FTMH, is an unusual finding. The deterioration was followed by spontaneous IOP normalization and macular hole closure. Such unexpected disease course, suggesting a possible autoimmune reaction, has not yet been described.

Risk factors of presenile nuclear cataract in health screening study.

BACKGROUND: To identify risk factors for the development of presenile nuclear cataract in health screening test. METHODS: The cross sectional study included a total of 532 eyes of 266 participants aged 30 to 49 years of Samsung Medical Center from February 2013 to April 2015. Presence of nuclear cataract was defined when the log MAR visual acuity with correction was greater than or equal to 0.2 and one or more of the following were met: Pentacam Nuclear Staging (PNS) grading score ≥ 1, average value of nuclear density ≥ 15%, maximum value of nuclear density ≥ 30%. Possible risk factors were obtained from blood tests and questionnaires of a health screening test of Samsung Medical Center. Association between nuclear cataract and risk factors was investigated using univariate and multivariate logistic regression analysis by generalized estimating equation (GEE) models. RESULTS: Five factors were significantly associated with presenile nuclear cataract: current smoking [odds ratio (OR) = 2.80, 95% confidence interval (CI), 1.10-7.12, p = 0.0310], non-exercise and high amount of daily physical exercise (OR = 3.99, 95% CI, 1.27-12.52, p = 0.0178; OR = 2.92, 95% CI, 1.38-6.22, p = 0.0053), asthma (OR = 8.93, 95% CI, 1.12-71.15, p = 0.0386), tuberculosis (OR = 4.28, 95% CI, 1.36-13.50, p = 0.0131), and higher total iron binding capacity (OR = 1.01, 95% CI, 1.00-1.02, p = 0.0059). CONCLUSIONS: Presenile nuclear cataract is related to current smoking, non-exercise or high amount of physical exercise, asthma, tuberculosis, and iron deficiency status. The association of non-exercise group and presenile nuclear cataract seems to be related to co-morbidity. Patients with asthma, tuberculosis, or iron deficiency anemia are recommended to receive frequent ophthalmic examination to detect cataract.

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.

αA-crystallin gene CpG islands hypermethylation in nuclear cataract after pars plana vitrectomy.

PURPOSE: To investigate the DNA methylation status of αA-crystallin gene in cataract secondary to pars plana vitrectomy. METHODS: Anterior capsular membranes of 40 eyes of 40 patients with cataract secondary to vitrectomy were collected. Another 20 eyes of 20 patients who received pars plana vitrectomy and phacoemulsification in the primary procedure, were recruited as control. Methylation status of the CpG islands of αA-crystallin gene was analyzed by pyrosequencing. Expression of αA-crystallin was evaluated by real-time polymerase chain reaction and western blot. RESULTS: In the post vitrectomy group, five patients with posterior subcapsular opacity and four patients with cortical opacity were excluded from further analysis. The remaining 31 patients with nuclear cataract were assigned into two groups according to tamponade types: 19 of octafluoropropane (C3F8) and 12 of silicone oil (SiO). The average nuclear color grading was elevated both in C3F8 and SiO groups after vitrectomy. Compared to the control group, hypermethylation of the CpG islands in the αA-crystallin gene promoter was found in both post vitrectomy groups, accompanied by significantly reduced αA-crystallin expression. No statistically significant differences were found between the C3F8 and SiO groups either for DNA methylation status or αA-crystallin expression. CONCLUSIONS: CpG islands hypermethylation of αA-crystallin gene may be involved in nuclear cataract formation after pars plana vitrectomy.

First in-human clinical performance of a new non-cavitating handheld lensectomy system in 665 consecutive cataract surgeries.

PURPOSE: To investigate the intraoperative performance and lens fragmentation efficacy of a non-cavitating handheld lensectomy system in mild, moderate, and severe cataract. SETTING: Ambulatory surgical centers. DESIGN: Retrospective consecutive case series. METHODS: 665 consecutive eyes underwent cataract surgery by 12 surgeons using a new handheld non-cavitating lensectomy system for nuclear fragmentations and extraction. Intraoperative measurements included surgical time, miLOOP pretreatment, and irrigation fluid use. RESULTS: Of the 665 eyes, 38 (6%), 468 (70%), 126 (19%), and 33 (5%) were of grade 1, 2, 3, and 4 nuclear densities, respectively, as graded by the surgeon intraoperatively. Successful nuclear fragmentation, lens extraction, and cortical removal were achieved in all eyes. Total nucleus fragmentation and extraction times were 70.1 seconds, 100.3 seconds, 132.6 seconds, and 287.9 seconds for grades 1, 2, 3, and 4, respectively ( P < .001). In addition, irrigation and aspiration cortical removal times were 64.1 seconds, 51.1 seconds, 48.5 seconds, and 59.0 seconds, respectively ( P = .14). There was a low rate of capsular tear (3 cases in 665 surgeries, 0.45%) and no other emergent adverse events. CONCLUSIONS: The miCOR handheld non-cavitating lensectomy system demonstrated nuclear fragmentation and extraction in the absence of intraocular cavitation across all grades of nuclear densities.

Simple fixation and storage protocol for preserving the internal structure of intact human donor lenses and extracted human nuclear cataract specimens.

PURPOSE: Increased use of phacoemulsification procedures for cataract surgeries has resulted in a dramatic decrease in the availability of cataractous nuclear specimens for basic research into the mechanism of human cataract formation. To overcome such difficulties, a fixation protocol was developed to provide good initial fixation of human donor lenses and extracted nuclei, when available, and is suitable for storing or shipping cataracts to laboratories where structural studies could be completed. METHODS: Cataractous lens nuclei (n=19, ages 12 to 74 years) were obtained from operating suites after extracapsular extraction. Transparent human donor lenses (n=27, ages 22 to 92 years) were obtained from the Ramayamma International Eye Bank. After the dimensions were measured with a digital caliper, samples were preserved in 10% formalin (neutral buffered) for 24 h and followed by fixation in 4% paraformaldehyde (pH 7.2) for 48 h. Samples were stored cold (4 °C) in buffer until shipped. Samples were photographed and measured before further processing for transmission electron microscopy. RESULTS: The dimensions of the samples varied slightly after short fixation followed by 1 to 5 months' storage before transmission electron microscopy processing. The mean change in the axial thickness of the donor lenses was 0.15±0.21 mm or 3.0±5.4%, while that of the extracted nuclei was 0.05±0.24 mm or 1.8±7.6%. Because the initial concern was whether the nuclear core was preserved, thin sections were examined from the embryonic and fetal nuclear regions. All cellular structures were preserved, including the cytoplasm, complex edge processes, membranes, and junctions. The preservation quality was excellent and nearly equivalent to preservation of fresh lenses even for the lens cortex. Cell damage characteristic of specific nuclear cataract types was easily recognized. CONCLUSIONS: The novel fixation protocol appears effective in preserving whole donor lenses and cataractous nuclei over a wide age range. Dimensions varied only 2%-3%, and fiber cell damage correlated well with standard fixation. These methods enable researchers and clinicians in remote settings to preserve donor lenses and rare examples of extracapsular extractions for detailed examination at later times.

Risk factors for cortical, nuclear, posterior subcapsular, and mixed lens opacities: the Los Angeles Latino Eye Study.

PURPOSE: To identify sociodemographic and biological risk factors associated with having cortical, nuclear, posterior subcapsular (PSC), and mixed lens opacities. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 5945 Latinos aged ≥ 40 years from 6 census tracts in Los Angeles, California. METHODS: Participants underwent an interview and detailed eye examination, including best-corrected visual acuity and slit-lamp assessment of lens opacities using the Lens Opacities Classification System II. Univariate and stepwise logistic regression analyses were used to identify independent risk factors associated with each type of lens opacity. MAIN OUTCOME MEASURES: Odds ratios for sociodemographic and biological risk factors associated with cortical only, nuclear only, PSC only, and mixed lens opacities. RESULTS: Of the 5945 participants with gradable lenses, 468 had cortical only lens opacities, 217 had nuclear only lens opacities, 27 had PSC only opacities, and 364 had mixed lens opacities. Older age, higher hemoglobin A(1c), and history of diabetes mellitus were independent risk factors for cortical only lens opacities. Older age, smoking, and myopic refractive error were independent risk factors for nuclear only lens opacities. Higher systolic blood pressure and history of diabetes were independent risk factors for PSC lens opacities. Older age, myopic refractive error, history of diabetes, higher systolic blood pressure, female gender, and presence of large drusen were independent risk factors for mixed lens opacities. CONCLUSIONS: The modifiable and non-modifiable risk factors identified in this study provide insight into the mechanisms related to the development of lens opacification. Improved glycemic control, smoking cessation and prevention, and blood pressure control may help to reduce the risk of having lens opacities and their associated vision loss.

Risk factors for incident cortical, nuclear, posterior subcapsular, and mixed lens opacities: the Los Angeles Latino eye study.

PURPOSE: To identify sociodemographic and biological risk factors associated with the 4-year incidence of nuclear, cortical, posterior subcapsular (PSC), and mixed lens opacities. DESIGN: Population-based, longitudinal study. PARTICIPANTS: We included 4658 Latinos ≥40 years from 6 census tracts in Los Angeles, California. METHODS: Participants underwent an interview and detailed eye examination, including best-corrected visual acuity and slit-lamp assessment of lens opacities using the Lens Opacities Classification System II (LOCS II) at baseline and again 4 years later. Each opacity type was defined in persons with a LOCS II score of ≥2. Univariate and forward stepwise logistic regression analyses were used to identify independent baseline risk factors associated with 4-year incidence of nuclear only, cortical only, PSC only, and mixed (when >1 opacity type developed in a person) lens opacities. These comprised 4 mutually exclusive groups, and were based on person rather than eye. MAIN OUTCOME MEASURES: Odds ratios for independent risk factors associated with 4-year incidence of nuclear-only, cortical-only, PSC-only, and mixed lens opacities. RESULTS: Of the 3471 participants with gradable lenses in the same eye at baseline and 4-year follow-up, 200 (5.8%) had incident nuclear-only opacities, 151 (4.1%) had incident cortical-only opacities, 16 (0.5%) had incident PSC-only lens opacities, and 88 (2.5%) had mixed lens opacities. Independent baseline risk factors for incident nuclear-only lens opacities included older age, current smoking, and presence of diabetes. Independent risk factors for incident cortical-only lens opacities included older age and having diabetes at baseline. Female gender was an independent risk factor for incident PSC-only lens opacities. Older age and presence of diabetes at baseline examination were independent risk factors for incident mixed lens opacities. Specifically, in diabetics, higher levels of hemoglobin A1c was associated with greater risk for 4-year incident nuclear-only, cortical-only and mixed lens opacities. CONCLUSIONS: Improved diabetic control and smoking prevention may reduce the risk of developing lens opacities. Understanding both modifiable and nonmodifiable risk factors provides insight into the development of lens opacification.

A Class I UV-blocking (senofilcon A) soft contact lens prevents UVA-induced yellow fluorescence and NADH loss in the rabbit lens nucleus in vivo.

It is known that fluorescence, much of it caused by UVA light excitation, increases in the aging human lens, resulting in loss of sharp vision. This study used an in vivo animal model to investigate UVA-excited fluorescence in the rabbit lens, which contains a high level of the UVA chromophore NADH, existing both free and bound to λ-crystallin. Also, the ability of a Class I (senofilcon A) soft contact lens to protect against UVA-induced effects on the rabbit lens was tested. Rabbit eyes were irradiated with UVA light in vivo (100 mW/cm(2) on the cornea) for 1 h using monochromatic 365 nm light. Irradiation was conducted in the presence of either a senofilcon A contact lens, a minimally UV-absorbing lotrafilcon A contact lens, or no contact lens at all. Eyes irradiated without a contact lens showed blue 365 nm-excited fluorescence initially, but this changed to intense yellow fluorescence after 1 h. Isolated, previously irradiated lenses exhibited yellow fluorescence originating from the lens nucleus when viewed under 365 nm light, but showed normal blue fluorescence arising from the cortex. Previously irradiated lenses also exhibited a faint yellow color when observed under visible light. The senofilcon A contact lens protected completely against the UVA-induced effects on fluorescence and lens yellowing, whereas the lotrafilcon A lens showed no protection. The UVA-exposure also produced a 53% loss of total NADH (free plus bound) in the lens nucleus, with only a 13% drop in the anterior cortex. NADH loss in the nucleus was completely prevented with use of a senofilcon A contact lens, but no significant protection was observed with a lotrafilcon A lens. Overall, the senofilcon A lens provided an average of 67% protection against UVA-induced loss of four pyridine nucleotides in four different regions of the lens. HPLC analysis with fluorescence detection indicated a nearly six-fold increase in 365 nm-excited yellow fluorescence arising from lens nuclear λ-crystallin after the in vivo UVA exposure. It is concluded that UVA-induced loss of free NADH (which fluoresces blue) may have allowed the natural yellow fluorescence of λ-crystallin and other proteins in the lens nucleus to become visible. Increased fluorescence exhibited by UVA-exposed λ-crystallin may have been the result of a UVA-induced change in the conformation of the protein occurring during the initial UVA-exposure in vivo. The results demonstrate the greater susceptibility of the lens nucleus to UVA-induced stress, and may relate to the formation of human nuclear cataract. The senofilcon A contact lens was shown to be beneficial in protecting the rabbit lens against effects of UVA light, including changes in fluorescence, increased yellowing and loss of pyridine nucleotides.

[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.

Structural and aggregation behavior of the human γD-crystallin mutant E107A, associated with congenital nuclear cataract.

PURPOSE: To analyze the conformational features and aggregation properties of the mutant protein E107A human γD-crystallin (HGDC), associated with congenital nuclear cataract. METHODS: cDNAs of wild type and E107A mutant were cloned and expressed in BL21 (DE3) pLysS cells and the proteins isolated and purified. The conformational properties and structural stability of the two proteins were compared using circular dichroism and fluorescence spectroscopic analysis. His-tagged cDNAs of the two proteins were transfected into HLE-3B human lens epithelial cells, and into HeLa cells and their in situ aggregation properties compared using immunofluorescence. RESULTS: The mutant protein was found to be remarkably similar in its secondary and tertiary structural features to the wild type. Its structural stability, analyzed by guanidinium chloride-induced denaturation, was also found to be similar. Its solubility, however, was over hundred-fold less than that of the wild type, and it had the tendency to precipitate and form light scattering particles. That it had the tendency to self- aggregate was noticed by using bis-ANS and Nile Red as extrinsic fluorescent probes. Such aggregation was also seen in situ when transfected and expressed in HLE-3B and in HeLa cell lines. CONCLUSIONS: E107A HGDC is yet another example of how a point mutation in the protein does not affect its conformation and stability but leads to substantial reduction in solubility and generation of light scattering aggregate particles in vitro and in situ when introduced into cell lines.

X-ray induced cataract is preceded by LEC loss, and coincident with accumulation of cortical DNA, and ROS; similarities with age-related cataracts.

PURPOSE: To compare age-related cataractous (ARC) changes in unirradiated mice lenses to those induced by head-only X-irradiation of 3 month-old mice. METHODS: lens epithelial cells (LECs) as well as partially degraded cortical DNA were visualized in fixed sections using 4',6-diamidino-2-phenylindole (DAPI) staining, and in fresh lenses using the vital stain Hoechst 33342. reactive oxygen species (ROS) activity was also visualized directly in fresh lenses using the vital dye Dihydrorhodamine (DHR). In fixed lenses an antibody specific for 8-OH Guanosine (8-OH-G) lesions was used to visualize DNA oxidative adducts from ROS damage. Alpha smooth muscle actin was visualized using specific antibodies to determine if myofibroblasts were present. Fluorescence was quantified using Laser Scanning Confocal Microscopy (LSCM). The degree of lens opacity and cataract formation was determined by slit lamp, or from digitalized images of light reflections taken with a low magnification light microscope. RESULTS: Using DNA- and ROS-specific vital fluorescent dyes, and laser scanning confocal microscopy we have previously described 4 changes in the aging rodent lenses: 1) a significantly decreased density of surface LECs in lenses from old compared to younger mice and rats; 2) a very large increase in retained cortical nuclei and DNA fragments in the secondary lens fibers of old rodent lenses; 3) increased cortical ROS in old rodent lenses; 4) increased cataract concomitantly with the cortical DNA and ROS increases. In the current study we report that these same 4 changes also occur in an accelerated fashion in mice given head-only X-irradiation at 3 months of age. In addition to vital staining of fresh lenses, we also examined sections from fixed eyes stained with DAPI or hematoxylin and eosin (H&E) and found the same loss of surface LECs and accumulation of undigested nuclei and debris in secondary lens fibers occur with age or following X-irradiation. In addition sections from fixed-eyes were examined for ROS damage to DNA with antibodies specific for 8-OH-G lesions. The frequency of 8-OH-G lesions increased dramatically in lenses from old unirradiated mice over 24 months of age, and similarly in X-irradiated lenses by 9-11 months post irradiation. The accumulation of cortical nuclei was not the result of conversion or invasion by myofibroblasts as tested by antibodies to a marker for such cells, alpha smooth muscle actin. CONCLUSIONS: X-irradiation damage induces a large decrease in surface LECs over a period of 3-11 months post X-irradiation of young mice. These changes are similar in extent to those seen in 24-29 months-old control mouse lenses with age-related cataracts. In 24+ month-old unirradiated mice the secondary lens fibers are not able to degrade nuclei or nuclear DNA efficiently and accumulate large numbers of cortical nuclei and nuclear fragments as well as ROS and 8-OHG lesions. X-irradiated lenses develop the same abnormalities in a more accelerated fashion. The extensive loss of LECS and accumulation of undegraded nuclei, ROS, and ROS damage may play a causal role in cataract generation in both unirradiated old mice and in previously irradiated young adult mice.

In vivo lens deficiency of the R49C alphaA-crystallin mutant.

The R49C mutation of alphaA-crystallin (alphaA-R49C) causes hereditary cataracts in humans; patients in a four-generation Caucasian family were found be heterozygous for this autosomal dominant mutation. We previously generated knock-in mouse models of this mutation and found that by 2 months of age, heterozygous mutant mice exhibited minor lens defects including reduced protein solubility, altered signaling in epithelial and fiber cells, and aberrant interactions between alphaA-crystallin and other lens proteins. In contrast, homozygous mutant alphaA-R49C knock-in mice displayed earlier and more extensive lens defects including small eyes and small lenses at birth, death of epithelial and fiber cells, and the formation of posterior, nuclear, and cortical cataracts in the first month of life. We have extended this study to now show that in alphaA-R49C homozygous mutant mice, epithelial cells failed to form normal equatorial bow regions and fiber cells continued to die as the mice aged, resulting in a complete loss of lenses and overall eye structure in mice older than 4 months. These results demonstrate that expression of the hereditary R49C mutant of alphaA-crystallin in vivo is sufficient to adversely affect lens growth, lens cell morphology, and eye function. The death of fiber cells caused by this mutation may ultimately lead to loss of retinal integrity and blindness.

Intraoperative fracture of phacoemulsification sleeve.

BACKGROUND: We describe a case of intraoperative fracture of phacoemulsification sleeve during phacoemulsification surgery. CASE PRESENTATION: Phacoemulsification surgery was performed in the left eye of a 58-year-old lady with grade II nuclear sclerosis & grade I cortical cataract. Towards the end of quadrant removal, there was anterior chamber instability with impaired followability of nuclear fragments. The distal part of the fractured sleeve remained inside the anterior chamber upon removal of the phacoemulsification probe. The retained sleeve was retrieved with a pair of forceps through the corneal incision site, which did not require widening. There was no missing fragments retained intraocularly and the patient had an uneventful recovery with vision of 20/25 at three months post-operatively. CONCLUSION: Phacoemulsification sleeve fracture is an uncommon complication. With early identification of this condition and proper management, major complications can be avoided.