New technology using crystalline lens autofluorescence for presbyopia and cataract grading.

PURPOSE: To investigate whether fundus autofluorescence (FAF) obtained using an ultra-wide field (UWF) fundus camera with an artificial opacity pattern can grade the degree of presbyopia and nuclear cataract. METHODS: Sixty eyes of 30 patients were enrolled in this prospective diagnostic study. The nuclear cataract (nuclear color/opalescence (NC/NO)) was graded according to the Lens Opacity Classification System III. The monocular near point of accommodation (NPA) was measured in eyes with NC3/NO3 or less. The mean gray value difference between the central 8 artificial opacity lesions and peripheral 8 artificial opacity lesions in the retinal AF was measured. The correlation between the mean gray value difference, NPA, and nuclear cataract grade was analyzed. RESULTS: The mean nuclear cataract grade of 60 eyes was 3.2 ± 1.6 and mean NPA of 37 eyes was 45.3 ± 16.1 cm. The mean gray value differences increased with increasing nuclear cataract grade (eyes with NC/NO grade 1, 53.3 ± 11.4; 2, 78.3 ± 13.6; 3, 95.2 ± 12.2; 4, 101.6 ± 11.9; 5, 109.0 ± 22.9; and 6, 121.1 ± 12.0; p < 0.001). The mean gray value difference was positively correlated with both the monocular NPA (R2 = 0.637; ß coefficient = 1.009; 95% CI, 0.748 to 1.271; p < 0.001) and nuclear cataract grade (R2 = 0.661; ß coefficient = 12.437; 95% CI, 10.097 to 14.778; p < 0.001). CONCLUSIONS: The FAF camera with an artificial opacity pattern attached can be used to effectively diagnose the degree of presbyopia and nuclear cataract.

Effect of surgical microscope and illuminated chopper on anterior chamber temperature.

BACKGROUND: To evaluate the effect of the light intensity of the surgical microscope and illuminated chopper on the anterior chamber temperature. STUDY DESIGN: Experimental study. METHODS: A model eye (Kitaro WetLab System; FCI Ophthalmics, Pembroke, MA, USA) was used in this experimental study. The illuminance of a surgical microscope (Leica M300; Leica Microsystems, Wetzlar, Germany) and illuminated chopper (iChopper NAM-25 GB; Oculight, Korea) with a light source (iVision; Oculight) was measured using an illuminometer. In addition, the temperature in the anterior chamber of the model eye filled with balanced salt solution when using the surgical microscope with a light intensity from level 1 to level 6 and the illuminated chopper at 99% light intensity was measured for 10 min. RESULTS: The anterior chamber temperature was increased by 0.2, 0.5, 1.0, and 1.4 ℃ when using the surgical microscope at level 3 (10050 lux), 4 (16490 lux), 5 (24900 lux), and 6 (32500 lux), respectively, for 10 min. The illuminated chopper at 99% light intensity (14893 lux) positioned in the anterior chamber increased the anterior chamber temperature by 0.2° C after 10 min, which was equal to the increase in the temperature caused by the surgical microscope at level 3. CONCLUSION: The photothermal effect of the illuminated chopper directly positioned in the anterior chamber appeared to be similar to that of a microscope with similar illuminance. Therefore, the illuminated chopper is safe in terms of anterior chamber temperature changes in cataract surgery.

Efficacy and safety of 1% and 2% rebamipide clear solution in dry eye disease: a multicenter randomized trial.

BACKGROUND: To evaluate the efficacy of 1% and 2% rebamipide clear solution in the treatment of dry eye disease (DED). METHODS: Two hundred twenty patients with DED were randomly assigned to one of three groups: the 1% rebamipide, 2% rebamipide, or placebo (eye drops containing the same ingredients, except for the active components). Each eye drop was instilled four times daily for 12 weeks. Changes in tear film break-up time (TBUT), corneal and conjunctival staining score, Schirmer 1 test, and the Ocular Surface Disease Index (OSDI) from baseline to 12-week visit between the study groups were compared for efficacy assessment. RESULTS: The mean age of study patients was 43.8±14.2 years. The 1% and 2% rebamipide groups showed greater improvement in TBUT (1.99±1.87 and 2.02±2.21 s) at 12 weeks from baseline than the placebo group (1.25±2.93 s). The 2% rebamipide group showed greater improvement in the corneal staining score (- 3.15±2.00) at 12 weeks from baseline than the placebo group (- 2.85±1.80). The 1% and 2% rebamipide groups showed improvement in Schirmer 1 test (1.27±3.86 and 1.50±4.14 mm) at 12 weeks of treatment, but not the placebo group (0.55±2.99 mm). Both the rebamipide groups and the placebo group showed significantly improved OSDI after treatment for 12 weeks; however, there was no significant difference among the three groups. CONCLUSIONS: 1% and 2% rebamipide clear solutions are an effective therapeutic option for improving TBUT and tear volume, and stabilizing the corneal staining score in DED.

Comparison of visual outcomes after two types of mix-and-match implanted trifocal extended-depth-of-focus and trifocal intraocular lenses.

PURPOSE: To compare visual outcomes between two types of mix-and-match implanted trifocal extended-depth-of-focus (EDoF) and trifocal intraocular lenses (IOLs). METHODS: A total of 212 eyes of 106 subjects with mix-and-match implanted FineVision Triumf and FineVision HP IOLs (Triumf-HP group) and 212 eyes of 106 subjects with mix-and-match implanted Zeiss AT LARA and AT LISA IOLs (AT LARA-LISA group) were enrolled in this retrospective case-control study. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), and binocular distance-corrected defocus curves were measured between 6 and 10 weeks after cataract surgery. RESULTS: There was no significant difference in UDVA among the four IOLs. UNVA was the best in eyes with the FineVision HP IOL (0.04 ± 0.06 logMAR), followed by eyes with the AT LISA IOL (0.07 ± 0.07 logMAR), the FineVision Triumf IOL (0.09 ± 0.09 logMAR), and the AT LARA IOL (0.11 ± 0.08 logMAR), respectively. The AT LARA-LISA group had better visual acuity than the Triumf-HP group between - 1.00 D and - 1.50 D of defocus, and the Triumf-HP group had better visual acuity than the AT LARA-LISA group between - 3.00 D and - 4.00 D of defocus. CONCLUSION: Mix-and-match implantation of trifocal EDoF and trifocal IOLs provided good visual outcomes in far, intermediate, and near distances. The mix-and-match implantation of Triumf-HP IOLs led to better visual outcomes in near vision, while that of the AT LARA-LISA IOLs led to better visual outcomes in intermediate vision.

Scleral fixation of subluxated or dislocated multifocal and multifocal toric intraocular lenses.

PURPOSE: To evaluate the feasibility of scleral fixation of subluxated or dislocated multifocal/multifocal toric intraocular lenses (IOLs) to rescue the IOL and restore both near and far vision. METHOD: A total of 18 eyes of 17 patients who underwent transscleral or intrascleral fixation of subluxated or dislocated multifocal or multifocal toric IOLs at 2.5 mm posterior to the limbus were enrolled. Preoperative uncorrected distance visual acuity (UDVA) and postoperative UDVA values were compared in this retrospective cross-sectional study. The postoperative corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA) at 40 cm, residual sphere, cylinder, spherical equivalent, and IOL centration were evaluated. RESULTS: The mean follow-up period was 4.0 ± 5.0 months. The mean preoperative UDVA was 0.73 ± 0.71 logMAR and the postoperative UDVA was 0.05 ± 0.10 logMAR, which was significantly improved relative to the preoperative UDVA. The mean postoperative CDVA was 0.00 ± 0.00 logMAR and the mean postoperative UNVA at 40 cm was 0.05 ± 0.07 logMAR. The mean postoperative residual sphere, cylinder, and spherical equivalent values were - 0.21 ± 0.41 D, - 0.29 ± 0.26 CD, and - 0.33 ± 0.39 D, respectively. Postoperative anterior segment photographs showed good centration of optics in all cases of single-piece foldable multifocal IOLs but a slight inferior decentration in one case of a three-piece multifocal IOL. CONCLUSION: Scleral fixation of subluxated or dislocated multifocal and multifocal toric IOLs could be one of the treatment options to rescue subluxated or dislocated multifocal IOLs and restore both near and far vision.

Development of an experimental model for ocular toxicity screening in Zebrafish.

BACKGROUND: To investigate the efficacy of a novel experimental model for exploring visual function using a contrast-optomotor response (C-OMR) assay made by applying the contrast sensitivity test to the OMR assay in zebrafish. METHODS: Zebrafish larvae were treated with 0 (control), 5, 10, or 15 µM gentamicin and digoxin for 24 h at four days post-fertilization (dpf). Zebrafish larvae were assessed using the C-OMR assay with graded contrast gray-white stripes at 5 dpf, and the results were expressed as the percentage of larvae that finished swimming for 30 s (n = 20 per each group). The same C-OMR assay was repeated four times using different larvae. RESULTS: The percentage of larvae that finished swimming within 30 s was significantly reduced in larvae treated with 5, 10, and 15 µM gentamicin and 10 and 15 µM digoxin as compared to the Control groups. The C-OMR assay could distinguish that the decrease in visual function was different depending on the concentration of gentamicin and digoxin (5, 10, and 15 µM), whereas the OMR test with one contrast gray-white stripe could not. CONCLUSIONS: The method of analyzing zebrafish OMR using graded contrast gray-white stripes is more sensitive than the OMR assay alone and may be more useful for assessing the drug toxicity and eye-related diseases to improve the understanding of drug-induced ocular side effects in the clinic.

Intraocular lens power calculation using adjusted corneal power in eyes with prior myopic laser vision correction.

PURPOSE: To evaluate the prediction accuracy of the intraocular lens (IOL) power calculation using adjusted corneal power according to the posterior/anterior corneal curvature radii ratio in the Haigis formula (Haigis-E) in patients with a history of prior myopic laser vision correction. METHODS: Seventy eyes from 70 cataract patients who underwent cataract surgery and had a history of myopic laser vision correction were enrolled. The adjusted corneal power obtained with conventional keratometry (K) was calculated using the posterior/anterior corneal curvature radii ratio measured by a single Scheimpflug camera. In eyes longer than 25.0 mm, half of the Wang-Koch (WK) adjustment was applied. The median absolute error (MedAE) and the percentage of eyes that achieved a postoperative refractive prediction error within ± 0.50 diopters (D) based on the Haigis-E method was compared with those in the Shammas, Haigis-L, and Barrett True-K no-history methods. RESULTS: The MedAE predicted using the Haigis-E (0.33 D) was significantly smaller than that obtained using the Shammas (0.44 D), Haigis-L (0.43 D), and Barrett True-K (0.44 D) methods (P < 0.001, P = 0.001, and P = 0.014, respectively). The percentage of eyes within ± 0.50 D of refractive prediction error using the Haigis-E (78.6%) was significantly greater than that produced using the Shammas (57.1%), Haigis-L (58.6%), and Barrett True-K (61.4%) methods (P = 0.025). CONCLUSION: IOL power calculation using the adjusted corneal power according to the posterior/anterior corneal curvature radii ratio and modified WK adjustment in the Haigis formula could improve the refraction prediction accuracy after cataract surgery in eyes with prior myopic laser vision correction.

A comparison of clinical outcomes and optical performance between monofocal and new monofocal with enhanced intermediate function intraocular lenses: a case-control study.

BACKGROUND: To compare clinical outcomes and optical performance of a new monofocal with enhanced intermediate function intraocular lenses (IOLs) with that of conventional monofocal IOLs. METHODS: Sixty eyes of 30 patients who underwent phacoemulsification with bilateral implantation of the ICB00 (15 patients) or ZCB00 (15 patients) IOLs were enrolled. Binocular corrected distance visual acuity (CDVA), distance corrected near visual acuity (DCNVA), and distance corrected intermediate visual acuity (DCIVA) were measured at 4 weeks after surgery. Patient satisfaction for overall, near, intermediate, and distance vision were assessed. The binocular defocus curves were measured. The root mean square of modulation transfer function (MTFRMS) was measured in the optical bench study. RESULTS: The mean binocular DCIVA was significantly better in the ICB00 group (0.01 logMAR) compared to the ZCB00 group (0.13 logMAR), but CDVA and DCNVA were not. The patient satisfaction for near and intermediate vision was significantly higher in the ICB00 group compared to the ZCB00. However, there was no difference in patient satisfaction for overall and distance vision between two groups. The defocus curves showed that mean visual acuity of the ICB00 group was significantly better than that of the ZCB00 group at between - 1.00 D to - 3.00 D of defocus. The ICB00 IOL had higher MTFRMS values at between - 0.50 D to - 2.00 D of defocus compared to the ZCB00 IOL. CONCLUSIONS: The ICB00 IOL provides better binocular intermediate vision and higher satisfaction for near and intermediate vision than the ZCB00 IOL while maintaining excellent distance vision.

Factors for good near and distance visual outcomes of multifocal intraocular lens with inferior segmental near add.

PURPOSE: This study was conducted to investigate factors related to postoperative good near and distance visual outcomes in the Lentis Mplus LS-313 MF20 (Oculentis Gmbh, Berlin, Germany) intraocular lens (IOL)-implanted eye. METHODS: A retrospective cross-sectional study analyzed a total of 198 eyes of 198 patients. Patients with 20/20-or-more uncorrected distance visual acuity (UDVA, 5 m) and J2-or-more uncorrected near visual acuity (UNVA, 40 cm) were distributed into the good visual outcome (GVO) group (n = 96), and the remaining patients were distributed into the moderate visual outcome (MVO) group (n = 102). Differences between the two groups were compared for patient age, preoperative measurements (kappa distance, kappa angle, and pupil size), and postoperative measurements (residual sphere, cylinder, and spherical equivalent) to explore factors related to good visual outcomes after IOL implantation. RESULTS: The average age of the GVO group (56.2 years) was significantly lower than that of the MVO group (58.6 years), and the average kappa distance of the former was significantly smaller than that of the latter. However, there were no significant differences between the two groups in kappa angle and pupil size. Notably, multivariate binary regression analysis revealed that multiple factors including age, residual cylinder, and spherical equivalent were associated with good visual outcomes. Based on the receiver operating characteristic curve, cutoff values regarded as good visual outcome following cataract surgery were calculated to be - 0.38 CD in residual cylinder and - 0.32 D in residual spherical equivalent. CONCLUSIONS: Patients with implanted Lentis Mplus LS-313 MF20 IOL who are young, had small kappa distance, and had low levels of postoperative residual cylinder and spherical equivalent tended to exhibit good vision at both near and distance. These results imply that surgeons should minimize postoperative residual cylinder and spherical equivalent to provide good visual outcomes to patients with implanted Lentis Mplus LS-313 MF20 IOL.

Eyelid squinting improves near vision in against-the-rule and distance vision in with-the-rule astigmatism in pseudophakic eyes: an eye model experimental study.

BACKGROUND: To elucidate whether eyelid squinting improves near and distance vision in against-the-rule (ATR) and with-the-rule (WTR) simple myopic astigmatism in pseudophakic eyes. METHODS: A refraction-model eye was mounted on a wavefront analyzer. The eyelid fissure was simulated using a slit placed horizontally in front of the model eye. Four different refractive statuses [- 1.50 diopters (D) and - 3.00 D of both WTR and ATR simple myopic astigmatism] were set using cylindrical lenses. For each refractive status (emmetropia, - 1.50 D WTR, - 1.50 D ATR, - 3.00 D WTR, and - 3.00 D ATR astigmatism), wavefront aberrations were measured, both with and without the slit, 40 times each. RESULTS: The 2 mm horizontal slit caused a hyperopic focus shift (+ 6.69 µm) in - 1.50 D WTR astigmatism, whereas, in - 1.50 D ATR astigmatism, it caused a myopic focus shift (- 2.01 µm). The astigmatism was decreased in the ATR astigmatism groups and increased in the emmetropia and WTR astigmatism groups, respectively. Total aberrations were decreased in the emmetropia and WTR astigmatism groups and increased in the ATR astigmatism groups. When the reference plane was set to the near plane, total aberrations were decreased in the ATR astigmatism groups. CONCLUSION: As the horizontal slit was placed in front of the model eye, the focus moves nearer in ATR astigmatism and farther in WTR astigmatism. These effects of eyelid cause improvement of near vision of pseudophakic eyes with ATR astigmatism.

A New Perspective on Dry Eye Classification: Proposal by the Asia Dry Eye Society.

The 2017 consensus report of the Asia Dry Eye Society (ADES) on the definition and diagnosis of dry eyes described dry eye disease as "Dry eye is a multifactorial disease characterized by unstable tear film causing a variety of symptoms and/or visual impairment, potentially accompanied by ocular surface damage." The report emphasized the instability of tear film and the importance of visual dysfunction in association with dry eyes, highlighting the importance of the evaluation of tear film stability. This report also discussed the concept of tear film-oriented therapy, which stemmed from the definition, and which is centered on provision of insufficient components in each tear film layer and ocular surface epithelium. The current ADES report proposes a simple classification of dry eyes based on the concept of tear film-oriented diagnosis and suggests that there are three types of dry eye: aqueous-deficient, decreased wettability, and increased evaporation. It is suggested that these three types respectively coincide with the problems of each layer: aqueous, membrane-associated mucins, and lipid/secretory mucin. Although each component cannot be quantitatively evaluated with the current technology, a practical diagnosis based on the patterns of fluorescein breakup is recommended. The Asia Dry Eye Society classification report suggests that for a practical use of the definition, diagnostic criteria and classification system should be integrated and be simple to use. The classification system proposed by ADES is a straightforward tool and simple to use, only through use of fluorescein, which is available even to non-dry eye specialists, and which is believed to contribute to an effective diagnosis and treatment of dry eyes.

Defining Dry Eye from a Clinical Perspective.

Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: "Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities." The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint.

Comparative evaluation of refractive outcomes after implantation of two types of intraocular lenses with different diopter intervals (0.25 diopter versus 0.50 diopter).

BACKGROUND: Intraocular lenses (IOLs) with different diopter (D) intervals may have different tolerance, and may provide different accuracy of refractive outcome after cataract surgery. The aim of the study is to compare the accuracy of refractive outcome after implantation of IOLs with different D intervals after cataract surgery. METHODS: A total of 80 eyes from 40 patients who underwent phacoemulsification with implantation of a 0.50 D interval Akreos AO IOL in one eye and a 0.25 D interval Softec HD™ IOL in the other eye were enrolled. The percentages of eyes with refractive prediction error within ±0.50 D at one month after surgery were compared. To evaluate the effect of the dioptric errors of the IOL itself on refractive prediction error, the percentage of eyes with refractive prediction error within ±0.25 D of the IOL with a standard deviation (SD) of ±0.40 D was compared with that of the IOL with a SD of ±0.11 D through Monte Carlo simulations. RESULTS: In this clinical study, the percentage of eyes with refractive prediction error within ±0.50 D by the Haigis formula in the Softec HD™ group (85.0%) was significantly greater than that in the Akreos AO group (57.5%; P = 0.027). In Monte Carlo simulations, all percentages of eyes with refractive prediction error within ±0.25 D by the Haigis and SRK/T formulas in the Softec HD™ group were significantly greater than those in the Akreos AO group. CONCLUSIONS: The IOL with a 0.25 D interval was more accurate than the IOL with a 0.50 D interval in predicting refractive outcome after cataract surgery. TRIAL REGISTRATION: Current Controlled Trials KCT0002192 , Retrospectively registered (Date of registration: 6 January 2017).

The Relationship Between Morphology and Function of the Meibomian Glands.

Meibomian gland dysfunction (MGD) is a leading cause of dry eye disease (DED). Meibomian gland dysfunction is divided into two major categories based on meibomian gland secretion: low delivery and high delivery. The low-delivery states are further classified as either hyposecretory or obstructive subtype, and the high-delivery state is termed "hypersecretory MGD." Two parameters are commonly used to evaluate meibomian gland function: lipid layer thickness and meibum quality and expressibility. To evaluate the morphology of meibomian glands, meibography is used to detect meibomian gland dropout. Functional and morphological changes of meibomian glands are often thought to be well correlated; in reality, many cases do not because some patients have characteristics of both hypersecretory and obstructive subtypes. We suggest that the MGD classification system should be modified to include a mixed subtype to explain such patients.

Influence of corneal power on intraocular lens power of the second eye in the SRK/T formula in bilateral cataract surgery.

BACKGROUND: To evaluate the effect of different adjustments of the refractive outcome of the first eye according to corneal power (K) in order to improve the intraocular lens (IOL) power calculation of the second eye in the SRK/T formula. METHODS: One hundred thirty-four patients who underwent uncomplicated bilateral, sequential phacoemulsification with AcrySof IQ implantation were enrolled. The optimal partial adjustment of the refractive outcome of the first eye according to K was retrospectively analyzed using a regression formula. RESULTS: In all patients, the optimal partial adjustment of the refractive outcome of the first eye was calculated as 56%. For K values between 42.8 D and 44.6 D, the optimal partial adjustment was calculated as 30%; however, this adjustment of the first eye did not significantly improve the refractive outcome in the second eye of the subgroup with K values between 42.8 D and 44.6 D. For K values greater than 44.6 D or less than 42.8 D, the optimal partial adjustments were calculated as 69% and 81%, respectively. According to these results, the adjustment of the first eye significantly improved the refractive outcome in the second eye from 0.36 to 0.26 D (P < 0.001) in the entire data set. This result was significantly lower than that using a single partial adjustment (56%) (0.28 D; P = 0.027). CONCLUSIONS: For K values greater than 44.6 D or less than 42.8 D, an approximately 70-80% adjustment of the first eye error should be considered. In contrast, for K values between 42.8 D and 44.6 D, a 30% or less adjustment should be considered in the SRK/T formula.

The effects of proinflammatory cytokines on the apoptosis of corneal endothelial cells following argon laser iridotomy.

The aim of this study was to evaluate the relationship between the expression of proinflammatory cytokines and the apoptosis of corneal endothelial cells after argon laser iridotomy (ALI). ALI was performed on each quadrant of the iris in the right eye of mice (ALI1 group). Left eyes were used as control group. The levels of interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-ß, and interferon (IFN)-γ in mice eyes were measured, and TUNEL staining was performed 12 h after ALI. Mice in the ALI-Dexa group were pretreated daily with an intraperitoneal injection of dexamethasone for 4 days before undergoing ALI and compared with mice without dexamethasone pretreatment (ALI2 group). Twelve corneas from six rabbits were incubated ex vivo with (n = 6) or without (n = 6) IL-1ß. TUNEL staining was performed 24 h after ex vivo incubation. In the mice experiment, the levels of IL-1ß, TNF-α, TGF-ß, and IFN-γ were increased in the ALI1 group compared to the control group. Although many TUNEL-positive cells were observed in the ALI1 group, those were not detected in the control group. Dexamethasone pretreatment inhibited the increase in the levels of all four proinflammatory cytokines and reduced TUNEL-positive cells. In the rabbit experiment, TUNEL-positive cells were increased in the incubated corneas with IL-1ß compared to those without IL-1ß. Expression of proinflammatory cytokines following ALI seems to play a role in the apoptosis of corneal endothelial cells after ALI. Dexamethasone pretreatment inhibited increases in proinflammatory cytokines and reduced the apoptosis of corneal endothelial cells.

Development of a program for toric intraocular lens calculation considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and effective lens position.

BACKGROUND: To evaluate the toric intraocular lens (IOL) calculation considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and effective lens position (ELP). METHODS: Two thousand samples of corneal parameters with keratometric astigmatism ≥ 1.0 D were obtained using bootstrap methods. The probability distributions for incision-induced keratometric and posterior corneal astigmatisms, as well as ELP were estimated from the literature review. The predicted residual astigmatism error using method D with an IOL add power calculator (IAPC) was compared with those derived using methods A, B, and C through Monte-Carlo simulation. Method A considered the keratometric astigmatism and incision-induced keratometric astigmatism, method B considered posterior corneal astigmatism in addition to the A method, method C considered incision-induced posterior corneal astigmatism in addition to the B method, and method D considered ELP in addition to the C method. To verify the IAPC used in this study, the predicted toric IOL cylinder power and its axis using the IAPC were compared with ray-tracing simulation results. RESULTS: The median magnitude of the predicted residual astigmatism error using method D (0.25 diopters [D]) was smaller than that derived using methods A (0.42 D), B (0.38 D), and C (0.28 D) respectively. Linear regression analysis indicated that the predicted toric IOL cylinder power and its axis had excellent goodness-of-fit between the IAPC and ray-tracing simulation. CONCLUSIONS: The IAPC is a simple but accurate method for predicting the toric IOL cylinder power and its axis considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and ELP.

The effect of posterior corneal flat meridian and astigmatism amount on the total corneal astigmatism estimated from anterior corneal measurements.

BACKGROUND: To evaluate the effects of posterior corneal astigmatism and the absolute flat meridian difference between anterior and posterior corneal surfaces (AMDAnt-Post) on the estimation of total corneal astigmatism using anterior corneal measurements (simulated keratometry [K]). METHODS: Ninety-nine eyes of 99 healthy participants were enrolled. Anterior, posterior, and total mean corneal power, cylinder power, flat meridian, and vector components J0, and J45 measured by a dual Scheimpflug camera were analyzed. The correlation between the posterior corneal cylinder power, AMDAnt-Post, and the difference in the cylinder power between simulated K and total cornea (cylinder power differenceSimK-Tot) were evaluated. RESULTS: The cylinder power differenceSimK-Tot was positively correlated with the posterior corneal cylinder power (rho = 0.704 and P < 0.001) and negatively correlated with AMDAnt-Post (rho = -0.717 and P < 0.001). In the multivariate linear regression analysis, anterior corneal J0 was strongly associated with the posterior corneal cylinder power and the AMDAnt-Post. When corneal J0 had a positive value, the cylinder power of simulated K tended to be larger than the total corneal cylinder power. In comparison, the opposite trend was presented in eyes with negative anterior corneal J0. When anterior corneal J0 was larger than 1.0 or smaller than -0.9, the errors from estimating the total corneal cylinder power using anterior corneal measurements tended to be larger than 0.25 D. CONCLUSION: Posterior corneal astigmatism should be considered for more accurate corneal astigmatism predictions, especially in eyes with anterior corneal astigmatism greater than 2.0 D of with-the-rule astigmatism or greater than 1.8 D of against-the-rule astigmatism.

Use of corneal power-specific constants to improve the accuracy of the SRK/T formula.

PURPOSE: To evaluate the effect of average corneal power (K) and axial length (AL) in a data-adjusted A-constant for improving the refractive outcome in the Sanders-Retzlaff-Kraff (SRK)/T formula. DESIGN: Retrospective, consecutive, case series. PARTICIPANTS: A total of 637 patients (637 eyes) who underwent uncomplicated phacoemulsification with implantation of the Acrysof IQ (IQ; Alcon, Fort Worth, TX; 314 eyes) or Akreos AO (AO; Bausch & Lomb, Rochester, NY; 323 eyes) intraocular lens (IOL) by a single surgeon. METHODS: The correlation among the K, AL, and predicted refractive error in the SRK/T formula was analyzed. Patients were divided into 2 subgroups, the first to calculate the different data-adjusted A-constants based on the K and the second to compare the median absolute error (MedAE) based on different A-constants with the traditional A-constant in the SRK/T formula. MAIN OUTCOME MEASURES: The data-adjusted A-constant and the MedAE (diopters [D]). RESULTS: The data-adjusted A-constant showed a decreasing trend as K increased. The data-adjusted A-constant was 119.04 in the IQ group and 118.27 in the AO group. The calculated A-constant was 119.33 in the IQ group and 118.57 in the AO group when the cornea was flatter than 43.0 D and 43.2 D, respectively. The A-constant was 118.71 in the IQ group and 117.96 in the AO group when the cornea was steeper than or equal to 44.7 D and 45.0 D, respectively. The MedAE decreased from 0.29 D to 0.23 D in the IQ group (P = 0.001) and from 0.44 D to 0.38 D in the AO group (P < 0.001) when different A-constants were used. The MedAE further decreased from 0.36 D to 0.24 D in the IQ group (P = 0.005) and from 0.58 D to 0.37 D in the AO group (P < 0.001) when subjects with K 1.00 D or more above or 1.00 D below the most accurate K in each group were compared. CONCLUSIONS: For a steep cornea, the calculated A-constant was smaller than that of the entire K, but for a flat cornea, a larger A-constant was calculated. Using different A-constants based on the K improved the refraction outcomes relying on the SRK/T formula.

Clinical Outcomes of Intrascleral Fixation of Intraocular Lens Compared to Ciliary Sulcus Implantation and Transscleral Fixation.

PURPOSE: To compare the clinical outcomes of intrascleral fixation of the three-piece intraocular lenses (IOLs) 2.5 mm posterior to the limbus with ciliary sulcus implantation and transscleral fixation 2.5 mm posterior to the limbus. METHODS: Sixty-five eyes of 65 patients who underwent ciliary sulcus implantation or transscleral or intrascleral fixation of the AMO Sensar AR40e IOL were retrospectively reviewed. The postoperative refractive prediction error, back-calculated effective lens position (ELP), corrected distance visual acuity (CDVA), and postoperative residual cylinder were compared. RESULTS: There were significant differences in the median (interquartile range) postoperative refractive prediction error (diopters [D]) among the three groups (p < 0.001): for ciliary sulcus implantation (33 eyes), -0.89 D (-1.21 to -0.56 D); for transscleral fixation (10 eyes), -0.40 D (-0.78 to -0.22 D); and for intrascleral fixation (22 eyes), 0.01 D (-0.28 to 0.34 D). Significant differences (p < 0.001) were observed in the median back-calculated ELP: for ciliary sulcus implantation, 4.35 mm (3.95 to 4.55 mm); for transscleral fixation, 4.51 mm (4.34 to 4.76 mm); and for intrascleral fixation, 4.90 mm (4.56 to 5.35 mm). There were no differences in the median postoperative CDVA (0, 0.10, and 0 logarithm of the minimum angle of resolution, respectively; p = 0.083) and the residual cylinder (-0.75, -1.50, and -0.63 D, respectively; p = 0.074) among three groups. CONCLUSIONS: Intrascleral fixation showed no myopic shift and the most posterior lens position, while ciliary sulcus implantation induced the greatest myopic shift and the most anterior lens position. However, there was no significant difference in the postoperative CDVA or astigmatism among the eyes with different IOL insertion methods, demonstrating good IOL stability and vision outcomes.