A randomized multicenter evaluation of the efficacy of 0.15% hyaluronic acid versus 0.05% cyclosporine A in dry eye syndrome.

Hyaluronic acid (HA) and cyclosporine A (CsA) eyedrops are commonly prescribed in dry eye syndrome (DES). The effectiveness of each preparation in DES is well-known, yet the superiority of one over another has been studied little. We assessed the efficacy and tolerability of 0.15% HA compared to combinations of 0.05% CsA plus 0.5% carboxymethylcellulose (CMC), and 0.15% HA plus 0.05% CsA in patients with moderate to severe DES. Total 438 patients with moderate to severe DES were recruited and randomized for one of the three treatments for 12 weeks. Effectiveness was assessed at baseline, 4- and 12-weeks. The primary endpoint was change in corneal staining score. The secondary endpoints were tear break-up time (TBUT), strip meniscometry (SM) score, ocular surface disease index (OSDI) score, and tolerability questionnaire. The change in corneal staining score for 0.15% HA from the baseline was non-inferior to that of 0.05% CsA. Corneal staining score, TBUT, SM score, and OSDI score improved in all groups without statistically significant intergroup differences. Better tolerability and lower prevalence of adverse drug reactions were seen in 0.15% HA. Our findings suggest that 0.15% HA may be equivalently effective and safer than 0.05% CsA in treating moderate to severe DES.

Corneal Endothelial Cell Changes After Femtosecond Laser-Assisted Cataract Surgery in Diabetic and Nondiabetic Patients.

OBJECTIVE: To compare corneal endothelial cell changes after femtosecond laser-assisted cataract surgery (FLACS) in diabetic and nondiabetic patients. METHODS: This retrospective study included patients with cataract who underwent FLACS performed by a single surgeon between August 2018 and November 2020. Changes in corneal endothelial cell density (ECD), hexagonality, coefficient of variation in cell size (CV), and central corneal thickness (CCT) at baseline and at the 1-month and 3-month postoperative follow-ups were investigated by dividing the patients into diabetic and nondiabetic groups. RESULTS: We included 75 patients (60% men, mean age: 57.7±11.4 years, range: 27-80 years) in the analysis: 31 diabetic patients (64% men, mean age: 58.7±11.9 years, range: 27-79 years) and 44 nondiabetic patients (56% men, mean age: 57.1±11.3 years, range: 34-80 years). No differences were observed between the two groups as regards preoperative and intraoperative parameters, the mean postoperative ECD, hexagonality, and CV. At 1 month postoperatively, the CCT was significantly greater in the diabetic group (P=0.034); however, at 3 months, there was no significant difference between the two groups (P=0.927). CONCLUSIONS: Changes in postoperative corneal endothelial cells were comparable between patients with and without diabetes after FLACS. Femtosecond laser-assisted cataract surgery seems to cause less damage to the corneal endothelium in diabetic patients because it uses less phacoemulsification energy.

Visual Performance and Optical Quality after Implantation of a New Generation Monofocal Intraocular Lens.

PURPOSE: To evaluate the performance of two intraocular lenses (IOLs). The new monofocal IOL using a higher-order aspheric optic (Tecnis Eyhance ICB00) was compared to a standard monofocal IOL (Tecnis monofocal ZCB00) of the identical platform and material. METHODS: The medical records of the patients who had undergone cataract surgery with implantation of either the ZCB00 or the ICB00 in the dominant eye from March 2020 to August 2020 and with available data from the 3-month visit were reviewed. Subjects with ocular comorbidities or corneal astigmatism greater than 1.00 diopters were excluded. The uncorrected near, intermediate, distance visual acuity and corrected distance visual acuity were the main outcome measures. Optical quality parameters measured using an optical quality analysis system, clinical records including age, sex, laterality, ocular dominance, and information related to refractory errors was also collected. Parameters related to the refractory errors were all uniformly based on the Barrett Universal II formula. RESULTS: Of the 197 recruited patients, 111 and 86 were implanted with the ICB00 and ZCB00, respectively. No statistically significant differences in baseline parameters were observed between the two groups. While no statistically significant differences in distance visual acuity or optical quality were found between the two groups, compared to the ZCB00 group, the ICB00 group showed significantly higher intermediate visual acuity (p < 0.001) and near visual acuity (p < 0.05) 3 months postoperatively. CONCLUSIONS: ICB00 provided superior intermediate vision and comparable distance performance and photic phenomena compared to a standard monofocal IOL.

Relationship between the partial blink rate and ocular surface parameters.

PURPOSE: To elucidate the relationship between partial blink rate (PBR) and ocular surface parameters. METHODS: We conducted a retrospective cross-sectional study of the patients who visited the Kim's Eye Hospital between March 2020 and July 2020. Blinking dynamics, tear film lipid layer thickness (LLT), non-invasive tear film break- up time (NITBUT), tear meniscus height (TMH), and meibomian gland (MG) dropout rate were assessed using the IDRA® Ocular surface analyzer (SBM SISTEMI, Inc., Torino, Italy) (IDRA). Dry eye symptoms were quantified by the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire scores. RESULTS: A total of 47 non-Sjögren dry eye patients (47 right eyes, mean age = 56.8 ± 14.5 [20-75] years, 66% female) were enrolled. Among the ocular surface parameters, PBR had strong correlations with MG dropout rate (r = 0.811; p < 0.01) and moderate correlations with SPEED scores (r = 0.596; p < 0.01). MG dropout rate and age had moderate correlations with SPEED scores (r = 0.416; p = 0.04 and r = 0.322; p = 0.03, respectively). Comparisons by sex revealed no significant difference in characteristics, except for the TMH value. The TMH of female patients (0.17 ± 0.07) was significantly higher than that of males (0.14 ± 0.04; p = 0.04). LLT showed no significant correlation with the other variables. CONCLUSION: PBR and MG dropout rates measured with IDRA were significantly correlated to dry eye symptoms.

Ocular surface analysis: A comparison between the LipiView® II and IDRA®.

PURPOSE: To compare the lipid layer thickness (LLT), meibomian gland (MG) dropouts, and blinking pattern determined by the analysis of images acquired from the LipiView® II (LVII) and the IDRA® Ocular surface analyzer. METHODS: A cross-sectional single-visit observational study was conducted. The LLT (minimum, maximum, and average), percentages of MG dropouts, and partial blink rates (PBR) were taken from both eyes of 47 participants using LVII and IDRA. Both devices were used to image the inferior eyelid of each participant in a random order. RESULTS: Forty-seven participants (mean age 56.77 ± 14.47 (21-79) years, 66% female) completed the study. There was no significant difference in LLT between the two devices. A significant difference in percentages of MG dropouts was obtained between the LVII (36.51 ± 17.53) and the IDRA (45.36 ± 21.87), p = 0.003). There was also a significant difference in PBR between the LVII (0.51 ± 0.37) and the IDRA (0.23 ± 0.27), p < 0.001). CONCLUSION: No significant difference in LLT was obtained between LVII and IDRA. IDRA had a significantly lesser percentage of MG dropout and a higher PBR compared to LVII. These results indicate that these devices should not be used interchangeably for the evaluation of MG dropouts and PBR.

Combined Phototherapeutic Keratectomy and Peripheral Anterior Stromal Puncture for the Treatment of Recurrent Corneal Erosion Syndrome.

PURPOSE: To investigate the efficacy of the combined phototherapeutic keratectomy (PTK) and peripheral anterior stromal puncture (ASP) compared with that of PTK alone in patients with recurrent corneal erosion syndrome (RCES). METHODS: The medical records of 25 patients (25 eyes) who underwent combined treatment of PTK and peripheral ASP for RCES from March 2016 to May 2017 were retrospectively reviewed. Twenty-three patients (23 eyes) treated with PTK alone from March 2015 to February 2016 served as a control group. All surgeries were performed by a single surgeon. This retrospective clinical study comprised 48 patients (48 eyes) who were followed up for more than 18 months. Clinical records of age, sex, laterality, etiology of RCES, and history of recurrence after treatment were evaluated. RESULTS: Twenty-five eyes were treated with combined PTK and ASP, and 23 eyes were treated with PTK only. The mean follow-up period was 19.63 ± 2.97 and 19.75 ± 6.83 months, respectively. There were no differences in baseline parameters between the groups. In the combined treatment group, one patient experienced recurrence 6 months after the surgery. In the single treatment group, five patients showed recurrence at 4, 7, 8, 11, and 13 months after the surgery, respectively. Compared to the single treatment group, the combined treatment group showed significantly lower recurrence rate (p < 0.05). All recurred patients required no additional treatment except temporary therapeutic contact lenses and topical lubricants. CONCLUSIONS: Our findings suggest that combined treatment of PTK and peripheral ASP is effective in alleviation of symptoms and prevention of recurrence in refractory RCES compared with treatment using PTK alone.

A case report of fulminant endophthalmitis caused by Streptococcus dysgalactiae in a patient with traumatic corneal laceration.

BACKGROUND: To report a case of enucleation caused by Streptococcus dysgalactiae endophthalmitis after traumatic corneal laceration. CASE PRESENTATION: A 69-year-old man with history of retinal detachment treated with vitrectomy and subsequent cataract surgery presented with traumatic corneal laceration while cutting grass. Appropriate repair of corneal laceration and intravitreal antibiotics (vancomycin, ceftazidime) injection was performed. S. dysgalactiae which was sensitive to the conventional antibiotics (Ampicillin, Ceftriaxone, Levofloxacin, etc.) detected by aqueous culture. One day following primary closure, the patient developed a complete hypopyon and vitreous membranes. Despite vigorous systemic and intravitreal antibiotics administration with vitrectomy, endophthalmitis was not controlled and patient's ocular pain was increased. The vitreous culture was also positive for S. dysgalactiae. Finally, total enucleation was performed 9 days after trauma due to fulminant endophthalmitis with severe scleritis. CONCLUSION: Progression of traumatic endophthalmitis associated with S. dysgalactiae can be fulminant. Sufficient warning to patient about enucleation and intensive care is needed in the case of this infection.

Lenticular fungal infection caused by Aspergillus in a patient with traumatic corneal laceration: a case report.

BACKGROUND: To report a case of lenticular infection caused by Aspergillus, which was diagnosed 13 weeks after traumatic corneal laceration. CASE PRESENTATION: A 60-year-old woman presented with traumatic corneal laceration including anterior lens capsule rupture and traumatic cataract after being hit with a chestnut in the right eye. There were multiple injuries due to tiny thorns of the chestnut, including the conjunctiva, sclera, cornea, and anterior lens capsule. But no visible foreign body was detected by slit-lamp examination. Topical corticosteroid was prescribed to resolve the conjunctival inflammation induced by the thorns of chestnut, which could have caused persistent irritation. As conjunctival injection and edema being decreased during outpatient clinical follow-up, embedded conjunctival foreign body was detected and surgically removed (1st surgery). Approximately 10 weeks after the trauma, severe inflammation of the anterior segment accompanied with hypopyon developed suddenly and at the same time embedded scleral foreign body was revealed. After removal of scleral foreign body (2nd surgery), unspecified mold species was cultured from the scleral foreign body in SDA (Sabouraud dextrose agar) plate. Suspicious corneal foreign body was removed as 3rd surgery and phacoemulsification of traumatic cataract was planned as 4th surgery. Aspergillus was finally detected from removed anterior capsule and fibrotic membrane during the operation. Fungal infection resolved successfully after administration of topical (1% voriconazole and 5% natamycin) and systemic (fluconazole) antifungal agents and phacoemulsification of traumatic cataract. CONCLUSION: Chestnut thorns can damage multiple ocular tissues simultaneously. Lens capsular rupture could result in fungal inoculation and lead to delayed lenticular fungal infection with complicated cataract formation. In cases of ocular trauma due to organic substances such as thorns and branches, the possibility of fungal infection should be considered.

Changes of tear film lipid layer thickness by 3% diquafosol ophthalmic solutions in patients with dry eye syndrome.

AIM: To evaluate the quantitatively changes in lipid layer thickness (LLT) when 3% diquafosol eye drop is used for dry eye patients using the tear film interferometer. METHODS: A total 124 participants (32 males, 92 females; mean age, 28.9y) diagnosed with dry eye disease (DED) received topical instillation of 4 ophthalmic solutions in one eye: diquafosol, normal saline, 0.1% sodium hyaluronate and 0.3% gatifloxacin, in a masked manner. LLT was measured using an interferometer at baseline and 20min after the instillation of each ophthalmic solutions. RESULTS: Changes of LLT after instillation (nm, mean± standard error) were as follows: 12.6±2.0 for diquafosol (P<0.001), 1.2±2.2 for normal saline (P=0.301), 1.5±2.0 for hyaluronate (P=0.495), and 0.5±3.2 for gatifloxacin (P=0.884). CONCLUSION: Topical instillation of diquafosol increases tear film LLT in DED patients. Diquafosol 3% eye drop might be effective treatment option of evaporative DED with meibomian gland dysfunction.

Accuracy of toric intraocular lens implantation using automated vs manual marking.

BACKGROUND: Accurate alignment of toric intraocular lens (TIOL) to steep corneal astigmatic axis is important to achieve effective postoperative results. The authors compare the accuracy of astigmatism correction using automated and manual marking in TIOL implantation during cataract surgery. METHODS: One hundred thirty-two eyes with nuclear density from Grade 2 to 4 were randomly subdivided into 2 groups (automated and manual marking). All patients underwent manual marking and the steep axis was compared to SensoMotoric Instruments (SMI). After phacoemulsification, 62 patients underwent toric IOL implantation using the SMI and 70 patients underwent toric IOL implantation using manual marking. Intraoperative measurement was the steep axis difference. Clinical measurements included preoperative and postoperative best corrected visual acuity (BCVA), and TIOL axis. RESULTS: The intraoperative steep axis difference between SMI and manual marking was 7.86 ± 6.4 degrees. The difference between the preoperative steep axis and the postoperative TIOL axis using SMI (3.63 ± 1.12 degrees) was significantly lower than that using manual marking (8.29 ± 2.23 degrees) (P < 0.05). CONCLUSIONS: The steep axis measurements may be different when using SMI vs. manual marking. The SMI is more accurate than manual marking for TIOL implantation during cataract surgery. TRIAL REGISTRATION: Current Controlled Trials ISRCTN12294725 , Retrospectively registered, on 20 July 2018.

Use of the Crystalline Lens Equatorial Plane as a New Parameter for Predicting Postoperative Intraocular Lens Position.

PURPOSE: To assess whether preoperative crystalline lens equatorial plane (LEP) reliably predicts the postoperative position of the intraocular lens (IOL). DESIGN: Comparative, interventional case series. METHODS: Phacoemulsification and IOL implantation (Group I, ZCB00; Group II, EC-1PAL; and Group III, CT Asphina) were performed for 104 eyes. Lens geometry parameters, including LEP, were obtained from a femtosecond laser cataract surgery system prior to surgery. LEP was defined as the distance from the front surface of the cornea to the equatorial plane of the crystalline lens. Postoperative anterior chamber depth (ACD) was measured using a Scheimpflug camera. Median absolute error was calculated using an optical ray-tracing method that incorporated LEP into an individualized eye model, and the results were compared with those from the Haigis formula. RESULTS: Preoperative ACD (3.27 ± 0.39 mm [R = 0.428], 3.30 ± 0.47 mm [R = 0.591], and 3.49 ± 0.39 mm [R = 0.373] in Groups I, II, and III, respectively) and LEP (4.81 ± 0.29 mm [R = 0.570], 4.84 ± 0.27 mm [R = 0.634], and 4.97 ± 0.23 mm [R = 0.565] in Groups I, II, and III, respectively) were found to have significant positive correlations with postoperative ACD (5.24 ± 0.40 mm, 5.02 ± 0.31 mm, and 5.19 ± 0.26 mm in Groups I, II, and III, respectively). Stepwise regression analysis showed that postoperative ACD was significantly correlated with LEP in all groups. Median absolute errors predicted by the ray-tracing method using LEP were smaller than those from the Haigis formula in all groups. CONCLUSIONS: LEP is a promising measure from preoperative crystalline lens geometry and could serve as a new parameter to improve refractive outcomes in cataract surgery.

Effectiveness of Toric Orthokeratology in the Treatment of Patients with Combined Myopia and Astigmatism.

PURPOSE: The purpose of this multi-institute, single-group clinical trial was to evaluate the effectiveness and safety of toric orthokeratology lenses for the treatment of patients with combined myopia and astigmatism. METHODS: A total of 44 patients were included in this clinical trial. The patients ranged in age from 7 to 49 years, with myopia of -0.75 to -6.0 diopters (D) and astigmatism of 1.25 to 4.0 D. After excluding 21 subjects, 23 subjects (39 eyes) were analyzed after toric orthokeratology lens use. The subjects underwent ophthalmologic examination after 1 day and 1, 2, 3, and 4 weeks of wearing overnight toric orthokeratology lenses. RESULTS: A total of 19 subjects (31 eyes) completed the trial after five subjects (eight eyes) dropped out. In the patients who completed the study by wearing lenses for 4 weeks, the myopic refractive error decreased significantly by 2.60 ± 2.21 D (p < 0.001), from -3.65 ± 1.62 to -1.05 ± 1.64 D. The astigmatic refractive error were also significantly decreased by 0.63 ± 0.98 D (p = 0.001), from 2.07 ± 0.83 to 1.44 ± 0.99 D. The mean uncorrected and corrected visual acuities before wearing the lenses were 2.14 ± 0.80 logarithm of the logMAR (logMAR) and 0.05 ± 0.13 logMAR, respectively, which changed to 0.12 ± 0.30 logarithm of the logMAR (p < 0.001) and 0.01 ± 0.04 logMAR (p = 0.156) after 4 weeks. No serious adverse reactions were reported during the clinical trial. CONCLUSIONS: Our results suggest that toric orthokeratology is an effective and safe treatment for correcting visual acuity in patients with combined myopia and astigmatism.

Analysis of anterior corneal astigmatism before cataract surgery using power vector analysis in eyes of Korean patients.

PURPOSE: To analyze the pattern of anterior corneal astigmatism before cataract surgery in Korean patients using power vector analysis and to assess the effect of aging on astigmatism. SETTING: Seoul St. Mary's Hospital, Catholic University of Korea, Seoul, South Korea. DESIGN: Cross-sectional retrospective study. METHODS: The study evaluated eyes with cataract from May 1, 2009, to July 1, 2013. All eyes received a complete ophthalmologic examination and manual keratometer measurement (OM-4) preoperatively. Power vector J0 and linear regression analyses were used to assess the association between age and anterior corneal astigmatism. RESULTS: The study evaluated 2847 right eyes (2847 patients). The mean age of the patients was 66.64 years ± 12.06 (SD) (range 20 to 100 years); 64.2% of the patients were women. The corneal J0 vector values became progressively negative and trended toward against-the-rule (ATR) astigmatism with increasing age (for men, r = -0.388 and P < .001; for women, r = -0.348 and P < .001). The ATR shift occurred earlier in men than in women. The regression coefficient of J0 values analyzed by age was -0.014 in men and -0.015 in women (both P < .001). CONCLUSIONS: Anterior corneal astigmatism in Korean patients with cataract shifted with age from with-the-rule to ATR in both sexes. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Tear Osmolarity and Ocular Surface Parameters as Diagnostic Markers of Ocular Graft-Versus-Host Disease.

PURPOSE: To evaluate the diagnostic value of tear osmolarity and several ocular surface parameters in screening for ocular surface alterations in ocular graft-vs-host disease (GVHD) patients. DESIGN: Case-control study. METHODS: Sixty-three patients with ocular GVHD and 74 healthy participants were screened for ocular surface changes using the Ocular Surface Disease Index (OSDI), tear osmolarity, Schirmer test, tear break-up time (TBUT), and fluorescein corneal staining. The severity of ocular GVHD was diagnosed according to the National Institutes of Health (NIH) grading system. The diagnostic sensitivity and specificity and cutoff values were determined for each ocular parameter using a receiver operating characteristic (ROC) curve and area under the curve (AUC) analysis. Significance was defined at P < .05. RESULTS: The tear osmolarity, corneal staining score, and OSDI score gradually increased as the severity of ocular GVHD increased, and Schirmer value gradually decreased as the GVHD grade increased in severity. The Schirmer test showed greatest diagnostic sensitivity and specificity for ocular GVHD (92.1% sensitivity, 85.7% specificity, cutoff = 9 mm), followed by the TBUT (87.3% sensitivity, 75.0% specificity, cutoff = 6 s), tear osmolarity (98.4% sensitivity, 60.7% specificity, cutoff = 311 mOsm/L), corneal staining score (66.7% sensitivity, 82.1% specificity, cutoff = 2), and OSDI score (77.8% sensitivity, 66.1% specificity, cutoff = 20.8). CONCLUSIONS: Multiple diagnostic modalities should be used to detect ocular surface changes in GVHD patients. The severity of ocular GVHD can be effectively monitored using tear osmolarity; however, additional studies are required.

Pupil-size alterations induced by photodisruption during femtosecond laser-assisted cataract surgery.

PURPOSE: To measure miosis after femtosecond laser pretreatment of cataract surgery and determine correlative factors. SETTING: Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, and Catholic University of Korea, Seoul, South Korea. DESIGN: Cross-sectional study. METHODS: Images extracted from surgical videos of femtosecond laser pretreatment and phacoemulsification were used to measure the pupil area. Quantitative analysis of pupil constriction was performed by comparing consecutive images obtained at the initiation of each procedure. Potential factors related to pupil constriction were examined, including laser parameters and anatomic measurements. RESULTS: The study enrolled 56 eyes. The mean pupil area decreased by 29.7% during the time it took to shift between procedures (shifting time). The total laser treatment duration was highly correlated with the reduction in the pupil area (r = -0.433, P = .001). The amount of intraoperative miosis was significantly correlated with the duration of lens fragmentation by the femtosecond laser (r = -0.416, P = .001) and of primary incision creation (r = -0.289, P = .031). Pupil constriction was correlated with patient age (r = -0.398, P = .002) and the laser capsulotomy-pupil margin distance (r = 0.395, P = .003), but not with suction-on time (r = -0.012, P = .930) or shifting time (r = -0.091, P = .506). CONCLUSIONS: The pupil area decreased significantly after femtosecond laser pretreatment of cataract surgery. Intraoperative miosis was most significantly correlated with laser pretreatment duration and patient age. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Wakayama symposium: interface between innate and adaptive immunity in dry eye disease.

Although the mechanism of dry eye disease is not clearly understood, it is certain that inflammation and the immune response play a major role in determining the health of the ocular surface in dry eye patients. Accurate ocular surface characterization during the early stages of dry eye disease is critical for successful treatment, because there exists no single standard, objective test to diagnose the early phase of dry eye disease. The treatment target should be direct to prevent the perpetuation of chronic inflammation and immune responses. Numerous studies have categorized dry eye disease as an autoimmune-related inflammatory disease. However, relatively little is known about how innate immune mechanisms act following a local insult, why some patients are particularly vulnerable, and why local inflammation fails to resolve in these patients. Within this review, particular attention will be given to the very early events and corresponding defense mechanism in dry eye disease. The transition from innate to adaptive immunity will also be discussed.

Objective assessment of nuclear cataract: comparison of double-pass and Scheimpflug systems.

PURPOSE: To compare the objective assessment of lens density by 2 systems (double-pass Optical Quality Analysis System and Pentacam Scheimpflug) in eyes with age-related nuclear cataract. SETTING: Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea. DESIGN: Cross-sectional study. METHODS: In eyes with age-related nuclear cataract, the objective lens density (0 to 100 points) was determined using the Scheimpflug system while subjective grading was achieved using the Lens Opacities Classification System III (LOCS III). The objective scatter index (OSI) (0 to 25) was assessed using the double-pass system. RESULTS: This study enrolled 47 patients (70 eyes). The mean OSI was 4.08 ± 2.22 (SD), and the mean Scheimpflug-measured lens density was 16.44 ± 4.36; the 2 parameters were correlated (r = 0.764, P<.01). There was a positive linear correlation between the OSI and LOCS III grading scores for nuclear opalescence and nuclear color (r = 0.772 and r = 0.752, respectively; P<.01). The cumulated dissipated energy (CDE) was strongly correlated with the OSI (r = 0.768) and Scheimpflug-measured lens density (r = 0.753). CONCLUSIONS: The OSI based on the double-pass system was correlated with the Scheimpflug-measured lens density, subjective lens grading, and CDE. The OSI may improve the preoperative evaluation of nuclear cataract and help predict phacodynamics in cataract surgery.