Effect of Artificial Tears on Preoperative Keratometry and Refractive Precision in Cataract Surgery.

Purpose: The primary objective was to investigate if treatment with artificial tears affected the variability of keratometry measurements for subjects with dry eyes prior to cataract surgery. The secondary objectives were to investigate whether treatment with artificial tears improved refractive precision and whether subjects with non-dry eyes had better refractive precision than subjects with dry eyes. Design: Prospective randomized controlled trial with three arms. Patients and methods: Dry eye diagnostics according to DEWS II were performed, and subjects with dry eyes were randomized to no treatment (group A1) or treatment with artificial tears two weeks prior to cataract surgery (group A2), with the third group (Group B, non-dry eyes) as a control. Keratometry was performed twice at baseline and twice after two weeks at the time of cataract surgery with three different optical biometers. The change in mean variability of keratometry (average K and magnitude of vector differences) and percentages of outliers after two weeks versus baseline were compared for group A2. The refractive and astigmatism prediction errors were calculated eight weeks after cataract surgery and compared for all three groups. Results: One hundred thirty-one subjects were available for analysis. There was no statistically significant difference in the mean variability of keratometry or percentages of outliers for group A2 from baseline to the time of cataract surgery. There was no statistically significant difference in refractive precision (absolute error and astigmatism prediction error) between any groups. Conclusion: Subjects with dry eyes (treated and non-treated) achieved the same refractive precision and percentages of outliers as subjects with non-dry eyes. Treatment with artificial tears for two weeks appeared inadequate to significantly affect variability in biometric measurements for patients with dry eyes prior to cataract surgery. DEWS II criteria for DED may not be optimal in a cataract setting.

The Significance of Dry Eye Signs on Preoperative Keratometry Measurements in Patients Scheduled for Cataract Surgery.

Purpose: The primary objective was to investigate if subjects with dry eyes had increased variability of keratometry measurements prior to cataract surgery compared to subjects with non-dry eyes. Secondary objectives were to determine which separate signs affected keratometry. Patients and Methods: This study was part of a prospective interventional randomized controlled trial. After dry eye diagnostics were performed (signs only) subjects were divided into sign of dry eye (SDE) positive and negative groups. To investigate variability, we performed two keratometry measurements for each subject with three different optical biometers: Anterion (OCT optical biometer), Eyestar (combined OCT and reflection-based optical biometer), and Lenstar (reflection based-optical biometer). Results: One hundred and thirty-one subjects were available for analysis. The variability of astigmatism was significantly higher for subjects with hyperosmolarity compared to normal eyes for the Lenstar, as was the percentage of eyes with variability of astigmatism greater than 0.25 D. The percentage of eyes with variability of average K greater than 0.25 D was higher for subjects with non-invasive keratograph break-up time <10 seconds (NIKBUT positive) compared to normal eyes for the Lenstar. Conclusion: Combined diagnostic criteria (signs only) showed no statistically significant differences for keratometry measurements between SDE positive and negative. Eyes with hyperosmolarity and NIKBUT positive showed statistically higher variability of keratometry measurements compared to normal eyes for Lenstar, but not for the Anterion or Eyestar biometers.

Refractive Predictability and Biometry Agreement of a Combined Swept Source Optical Coherence and Reflectometry Biometer Compared to an Optical Low Coherence Reflectometry Biometer and an SS-OCT Biometer.

Purpose: To evaluate the agreement of refractive predictability of a swept-source optical coherence tomography (SS-OCT) biometer, which uses segmental AL calculation, with another SS-OCT biometer, and an optical low coherence reflectometry (OLCR) biometer. The secondary objective was to describe the refractive outcomes, visual acuities, and the agreement of different preoperative biometric parameters. Patients and Methods: The study was a retrospective one-arm study of refractive and visual outcomes after successful cataract surgery. Preoperative biometric data were collected with two different SS-OCT device (Argos, Alcon Laboratories and Anterion, Heidelberg Engineering) and an OLCR device (Lenstar 900, Haag-Streit). The Barrett Universal II formula was used to calculate IOL power for all three devices. Follow-up examination was 1-2 months after surgery. The main outcome measure, refractive prediction error (RPE), was calculated as the achieved postoperative refraction minus the predicted refraction for each device. Absolute error (AE) was calculated by reducing the mean error to zero. Results: The study included 129 eyes of 129 patients. The mean RPE was 0.06, -0.14 and 0.17 D for the Argos, Anterion and Lenstar, respectively (p < 0.01). The Argos also had the lowest absolute RPE, while the Lenstar had the lowest median AE, but this was not statistically significant (p > 0.2). The percentages of eyes with RPE within ±0.5 was 76%, 71%, and 78% for the Argos, Anterion, and Lenstar, respectively. The percentages of eyes with AE within 0.5 D was 79%, 84%, and 82% for the Argos, Anterion and Lenstar, respectively. None of these percentages were statistically significantly different (p > 0.2). Conclusion: All three biometers showed good refractive predictability with no statistically significant differences in AE or percentages of eyes within ± 0.5 D of RPE or AE. The lowest arithmetic RPE was found with the Argos biometer.

The Significance of Inter-Eye Osmolarity Difference in Dry Eye Diagnostics.

Purpose: The purpose of this study was to evaluate the diagnostic value of inter-eye osmolarity differences in relation to dry eye symptoms and other non-osmolar signs of dry eye disease. Patients and Methods: One hundred ninety one participants who attended a larger interventional study of dry eye disease prior to and after cataract surgery were analyzed for dry eye disease (DED). Dry eye diagnostics were performed for all subjects according to the DEWS II criteria: tear osmolarity was collected from both eyes with the TearLab system, non-invasive Tear film break up time (NIKBUT) was obtained on the test eye with Keratograph and ocular surface staining (OSS) was evaluated using the Oxford schema. The Ocular Surface Disease Index (OSDI) questionnaire was used to assess symptoms. Inter-eye osmolarity greater than 8, which is considered as a sign of DED according to the TearLab user manual, was evaluated and compared with other non-osmolar signs of DED. Results: The 191 subjects were divided into three groups according to osmolarity measurements. Sixty-five subjects had normal osmolarity (below 308 mOsmol/L in both eyes and less than 9 mOsmol/L difference between the eyes), 107 had high osmolarity (308 mOsmol/L or higher in one of the eyes) and 19 had an inter-eye difference >8 mOsmol/L or higher, with neither eye having osmolarity higher than 307 mOsmol/L. Signs and symptoms in this last group were not correlated with the high osmolarity group or the normal group, though they appeared more similar to the normal group. Conclusion: The diagnostic value of inter-eye osmolarity difference in predicting symptoms or other non-osmolar signs of dry eyes appears weak. Our study suggests that the criterion of an inter-eye difference of 8 mOsmol/L is not a useful cut-off for diagnosing dry eyes based on osmolarity.

Efficacy of a Secondary Trifocal Sulcus IOL in Providing Near and Intermediate Vision in Patients with Prior Myopic Laser Vision Correction and Cataract Surgery.

Purpose: To evaluate the visual function of patients with a history of prior laser vision correction and cataract surgery with implantation of a monofocal primary IOL after subsequent implantation of a secondary sulcus trifocal intraocular lens (IOL). Setting: One clinical practice in Haugesund, Norway. Design: Prospective, single arm, non-interventional unmasked study. Methods: Eligible subjects who had previous laser vision correction and cataract surgery involving implantation of a monofocal IOL in the capsular bag of one or both eyes were subsequently implanted with a secondary IOL in the sulcus. Postoperative uncorrected and best distance-corrected visual acuities (VAs) were measured at distance (4 m), intermediate (60 cm), and near (40 cm), along with low contrast visual acuity and the monocular distance corrected defocus curve. Results: Twenty-five eyes were evaluated from 7 to 24 months after trifocal implantation. The mean monocular uncorrected VAs were 0.06, 0.21 and 0.10 logMAR at distance, intermediate and near, respectively. Uncorrected near VA was 0.2 logMAR or better in 80% of eyes (20/25). VA of 0.2 logMAR or better at all test distances was achieved in 15/25 eyes (60%) in the uncorrected state and 17/25 eyes (68%) when corrected for distance vision. Binocular uncorrected distance visual acuity was 0.1 logMAR or better in all subjects while binocular uncorrected near visual acuity was 0.1 logMAR or better in all but one subject. The defocus curve showed a range of functional vision from distance to 30 cm. No adverse events were identified. Conclusion: The trifocal sulcus IOL provided excellent distance and near vision and a good range of functional vision, similar to results obtained when a primary trifocal IOL is implanted. It is a viable option to provide better intermediate and near vision to patients with a prior history of refractive surgery and a monofocal IOL implanted.

Refractive Precision of Ray Tracing IOL Calculations Based on OCT Data versus Traditional IOL Calculation Formulas Based on Reflectometry in Patients with a History of Laser Vision Correction for Myopia.

PURPOSE: To compare the refractive predictability of ray tracing IOL calculations based on OCT data versus traditional IOL calculation formulas based on reflectometry in patients with a history of previous myopic laser vision correction (LVC). PATIENTS AND METHODS: This was a prospective interventional single-arm study of IOL calculations for cataract and refractive lens exchange (RLE) patients with a history of myopic LVC. Preoperative biometric data were collected using an optical low coherence reflectometry (OLCR) device (Haag-Streit Lenstar 900) and two optical coherence tomography (OCT) devices (Tomey Casia SS-1000 and Heidelberg Engineering Anterion). Traditional post LVC formulas (Barret True-K no-history and Haigis-L) with reflectometry data, and ray tracing IOL calculation software (OKULIX, Panopsis GmbH, Mainz, Germany) with OCT data were used to calculate IOL power. Follow-up examination was 2 to 3 months after surgery. The main outcome measure, refractive prediction error (RPE), was calculated as the achieved postoperative refraction minus the predicted refraction. RESULTS: We found that the best ray tracing combination (Anterion-OKULIX) resulted in an arithmetic prediction error statistically significantly lower than that achieved with the best formula calculation (Barret True-K no-history) (-0.13 D and -0.32 D, respectively, adjusted p = 0.01), while the Barret TK NH had the lowest SD. The absolute prediction error was 0.26 D and 0.35 D for Anterion-OKULIX and Barret TK NH, respectively, but this was not statistically significantly different. The Anterion-OKULIX calculation also had the highest percentage of eyes within ± 0.25, compared to both formulas and within ±0.50 and ±0.75 compared to the Haigis-L (p = 0.03). CONCLUSION: Ray tracing calculation based on OCT data from the Anterion device can yield similar or better results than traditional post LVC formulas. Ray tracing calculations are based on individual measurements and do not rely on the ocular history of the patient and are therefore applicable for any patient, also without previous refractive surgery.

Repeatability of OCT-Based versus Scheimpflug- and Reflection-Based Keratometry in Patients with Hyperosmolar and Normal Tear Film.

PURPOSE: To compare the repeatability of keratometry between different instruments in patients with hyperosmolar tear film and a control group. PATIENTS AND METHODS: Subjects with tear-film osmolarity of 316 mOsm/L or more in either eye or 308 m/Osm/L or lower in both eyes were assigned to the hyperosmolar and the control group, respectively. The test eye was the eye with higher osmolarity in the hyperosmolar group and randomly chosen in the control group. The repeatability of keratometry was compared between a reflectometry device (Haag-Streit Lenstar 900), a Scheimpflug device (Oculus Pentacam HR) and two optical coherence tomography (OCT) devices (Tomey Casia SS-1000 and Heidelberg Anterion), based on two measurements from each device. RESULTS: The study included 94 subjects (31 hyperosmolar and 63 controls). Both OCT devices had higher mean differences of average simulated keratometry (SimK) vs the Lenstar in both groups, though all differences in means were <0.07 D. The Casia had the highest mean vector difference of SimK astigmatism in the control group (differences in means <0.11 D). These differences of the instruments were statistically significant (p < 0.02), except for the Anterion in the control group. With all subjects, the coefficient of repeatability varied from 0.1 to 0.3 for average SimK (highest for both OCT devices) and from 0.4 to 0.7 for SimK astigmatism (highest for the Casia). Similar results were found for total corneal power (OCT devices compared to the Pentacam). CONCLUSION: Both OCT devices show more variability in average SimK and the Casia more variability in SimK astigmatism compared to the Lenstar and the Pentacam. However, the results suggested that repeatability was not influenced by osmolarity.

Prevalence of Signs and Symptoms of Dry Eye Disease 5 to 15 After Refractive Surgery.

PURPOSE: To compare the prevalence of dry eye disease (DED) as determined by signs and symptoms in patients with a history of laser vision correction (LVC) or implantable collamer lens (ICL) implantation 5-15 years ago with a matched control group with no history of refractive surgery. PATIENT AND METHODS: This was a cross-sectional case-control study. The subject population included patients who had LVC or ICL 5 to 15 years ago. The control group was age matched. A test eye was randomly chosen. Subjects were required to have good ocular health. DED was evaluated using categorical cut-off criteria for tear film osmolarity (measured in both eyes), the subjective Ocular Surface Disease Index (OSDI), the dynamic Objective Scatter Index (OSI), non-invasive keratography tear break-up time (NIKBUT), meibography, and the Schirmer 1 test. RESULTS: The study included 257 subjects (94 LVC, 80 ICL, 83 control). The frequency of hyperosmolarity was significantly higher in the LVC group vs the control (73% vs 50%, p = 0.002), In contrast, the frequency of subjective symptoms tended to be lower in the LVC group than in the control group (19% vs 31%; p = 0.06). These differences were not seen between the ICL and control group. CONCLUSION: The results suggest that LVC may cause tear film instability as indicated by hyperosmolar tears up to 15 years after surgery, with few subjective symptoms of dry eye. This may have implications for IOL calculations for cataract or refractive lens exchange later in life.

Presbyopic refractive lens exchange with trifocal intraocular lens implantation after corneal laser vision correction: Refractive results and biometry analysis.

PURPOSE: To evaluate the refractive and biometry results of presbyopic refractive lens exchange (RLE) with trifocal intraocular lens (IOL) implantation in eyes with previous myopic or hyperopic corneal laser vision correction (LVC). SETTINGS: Memira AS, Norway, Sweden, and Denmark. DESIGN: Retrospective case series. METHODS: The refractive results included the manifest refraction spherical equivalent, uncorrected near (UNVA) and distance (UDVA) visual acuities, corrected distance visual acuity, safety, efficacy, and precision. The biometry analysis included the refractive prediction error (RPE), median absolute error (MedAE), and percentage of eyes within a certain RPE range for the formulas from the American Society of Cataract and Refractive Surgery (ASCRS) online calculator. RESULTS: The study comprised 241 eyes. Six months postoperatively, 60.0% of eyes were within ±0.25 diopter (D), 80.9% within ±0.50 D, and 97.9% within ±1.00 D of emmetropia. There were no statistical differences in the mean monocular UDVA (0.87 ± 0.20 [SD]), safety index (0.98 ± 0.09), or efficacy index (0.81 ± 0.18) between the myopic ablation group and hyperopic ablation group. Binocularly, 85% of patients had simultaneous UDVA and UNVA of 0.9 or better and Jaeger 3, respectively. The ASCRS online calculator formulas gave different performances for previous myopic and hyperopic ablation profiles. Using optimized constants and nomogram for correcting the mean RPE improved the MedAE. CONCLUSIONS: Presbyopic RLE was safe and effective in selected cases with a history of LVC. The use of optimized IOL constants and nomograms can improve the refractive precision of lens-based refractive surgery.

The Use of Capsular Tension Rings to Reduce Refractive Shift in Patients With Implantation of Trifocal Intraocular Lenses.

PURPOSE: To determine whether use of a capsular tension ring (CTR) can increase refractive stability in patients with implantation of two different trifocal intraocular lenses (IOLs). METHODS: A prospective, consecutive series of eyes underwent refractive lens exchange with implantation of two different trifocal IOL designs: FineVision Micro F (non-toric) and FineVision POD FT (toric) (PhysIOL, Liege, Belgium). Power calculation was determined using the Haigis formula. Refractive lens exchange surgery was performed according to the standard Memira protocol. Refractive results and stability were assessed at 2 weeks and 3 months postoperatively. RESULTS: Three hundred eighty-eight eyes were included in the analysis. Overall, 71% and 76% of MicroF eyes implanted with (n = 139) and without (n = 104) a CTR, respectively, had hyperopic shift; 9% of MicroF eyes with a CTR had a shift of greater than +0.50 to +0.75 or less diopters (D) and 4% had a shift of greater than +0.75 D. In MicroF eyes without a CTR, 12% and 3% of eyes experienced a refractive shift of greater than +0.50 to +0.75 D or less and greater than +0.75 D, respectively. In the POD FT group, 72% and 69% of eyes with (n = 81) and without (n = 64) a CTR, respectively, had hyperopic shift; 10% of POD FT eyes with a CTR had a change of greater than +0.50 to +0.75 D or less and 7% had a shift of greater than +0.75 D. In POD FT eyes without a CTR, 13% and 3% experienced a refractive shift of greater than +0.50 to +0.75 D or less and greater than +0.75 D, respectively. For the MicroF design, the best refractive stability was found in the CTR group and the poorest stability in the non-CTR group (P = .084). For the POD FT design, the best refractive stability was found in the non-CTR group and the poorest stability in the CTR group (P = .297). CONCLUSIONS: Up to 7% of eyes implanted with FineVision trifocal IOLs had a hyperopic shift of greater than +0.75 D approximately 2 weeks to 3 months postoperatively. Using a CTR in MicroF eyes had no statistically significant effect on refractive stability. Placing a CTR with POD FT IOLs appeared to reduce refractive stability, although not significantly. [J Refract Surg. 2017;33(12):802-806.].