Intraocular Pressure and Eyedrop Usage Reduction with Intracameral Bimatoprost Implant.

Purpose: Sustained intraocular drug delivery devices are being developed to lower intraocular pressure (IOP) and improve adherence in patients with glaucoma. The purpose of this study was to assess the IOP and eyedrop usage reduction effects of intracameral bimatoprost implants. Methods: We retrospectively reviewed the records of 46 eyes from 38 patients who received an intracameral implant containing 10 µg of bimatoprost as a replacement or addition to their existing eyedrop regimen and investigated IOP, eyedrop usage, and adverse effects. Results: Patients were followed for an average of 274 ± 104 (mean ± standard deviation) days after implant. Mean reduction in IOP (mmHg) at 3 months ±30 days, 6 months ±60 days, and 12 months ±90 days postoperation compared to baseline was 1.26 ± 2.53 (P = 0.002), 0.93 ± 4.71 (P = 0.098), and 1.35 ± 5.24 (P = 0.053), respectively. Reduction in eyedrops at 3 months ±30 days, 6 months ±60 days, and 12 months ±90 days postoperation compared to baseline were 0.62 ± 0.49 (P < 0.001), 0.55 ± 0.73 (P < 0.001), and 0.51 ± 0.71 (P < 0.001), respectively. Fifteen eyes (32.6%) experienced implant failure, defined as either restarting IOP-lowering eyedrops or undergoing surgical intervention, at an average of 260 ± 122 days after implant. Conclusions: While some patients eventually experienced implant failure, intracameral bimatoprost implants may result in fewer adverse reactions and successfully lower IOP and eyedrop burden over a longer period than previously reported.

Comparison of Barrett and Emmetropia Verifying Optical Toric Calculators.

PURPOSE: The purpose of this study was to compare the Barrett (BTC) and Emmetropia Verifying Optical (EVO) Toric Calculators' performance with regards to prediction of residual post-operative astigmatism after cataract surgery. METHODS: This was a secondary analysis of de-identified data that was collected as part of a prospective multicenter clinical trial in which 109 eyes from 109 patients were implanted with a monofocal toric intraocular lens (IOL). Post-operative biometry was used to calculate the predicted post-operative residual astigmatism for each eye using the two different calculators. The vector difference between the actual and predicted residual astigmatism was calculated. RESULTS: The mean absolute astigmatism prediction errors were 0.59 ± 0.38 D and 0.59 ± 0.36 D for the BTC and EVO calculators, respectively (p = 0.98). The centroid of the prediction errors were 0.18 D @ 89° ± 0.68 D and 0.20 D @ 89° ± 0.66 D, respectively (p = 0.21). The proportion of eyes in which the astigmatism prediction error was ≤0.5 D was 50% for BTC and 46% for EVO (p = 0.28). The proportion of eyes in which the post-operative astigmatism orientation was correctly predicted as being against-the-rule, with-the-rule, or oblique was 81% for BTC and 77% for EVO (p = 0.15). CONCLUSION: The Barrett and Emmetropia Verifying Optical Toric Calculators had similar performance with regards to their astigmatism prediction accuracy.

Correlation Between Keratometric and Refractive Astigmatism in Pseudophakes.

PURPOSE: To investigate the relationship between measured anterior, posterior, and total keratometric astigmatism and post-operative refractive astigmatism (RA) after cataract surgery. PATIENTS AND METHODS: This was a retrospective analysis of eyes that consecutively underwent pre-operative measurements of keratometric astigmatism with a swept-source optical coherence tomography (SS-OCT)-based optical biometer and dual-Scheimpflug/Placido disc corneal topographer, cataract surgery with implantation of a monofocal intraocular lens, and post-operative manifest refraction. The difference between post-operative refractive astigmatism and keratometric astigmatism measured using four different ways [Keratometry (K), Simulated Keratometry (SimK), Total Keratometry (TK), and Total Corneal Power (TCP)] was calculated. RESULTS: For all 118 eyes, a smaller mean vector difference between post-operative refractive astigmatism and measured keratometric astigmatism was realized with TK (0.08 @ 151) vs TCP2 (0.30 @ 174; p < 0.0006), as well as with K (0.26 @ 173) vs SimK (0.52 @ 177; p = 0.036). The mean vector difference between post-operative refractive astigmatism and TK astigmatism was 0.31 @ 097, 0.21 @ 163, and 0.69 @ 179 in eyes with against-the rule (ATR), oblique, and with-the-rule (WTR) anterior corneal astigmatism, respectively (p < 0.0006). On the other hand, posterior corneal astigmatism did not significantly change with the orientation of anterior corneal astigmatism [0.10 @ 180 for ATR, 0.22 @ 180 for oblique, and 0.28 @ 180 for WTR (p = 0.58)]. CONCLUSION: Compared with the other measures of corneal astigmatism, total keratometric astigmatism from the SS-OCT device most closely correlated with post-operative RA. The difference between anterior corneal astigmatism and refractive astigmatism is not completely explained by the contribution from the posterior cornea. Other contributors, such as lens tilt or neuro-adaptation, may be at play.

Anterior, posterior, and nonkeratometric contributions to refractive astigmatism in pseudophakes.

PURPOSE: To investigate the relationship between measured anterior (ACA) and posterior (PCA) keratometric astigmatism and postoperative refractive astigmatism (RA) and to quantify noncorneal astigmatism (NCA) contributions to RA. SETTING: Penn State College of Medicine, Hershey, Pennsylvania, USA. DESIGN: Retrospective consecutive case series. METHODS: Consecutive eyes underwent preoperative biometry (IOLMaster 700) and tomography/topography using a dual Scheimpflug-placido disk-based device (Galilei G4), cataract surgery with implantation of a monofocal intraocular lens (IOL), and postoperative manifest refractions. RA was compared with keratometric astigmatism using the following methods: IOLMaster, SimK, CorT, SimK + measured PCA, total corneal power at the corneal plane (TCP2), and CorT(Total). An ocular residual astigmatism (ORA) vector was calculated between RA and each measured astigmatism. RESULTS: Analysis was based on 296 eyes. ORA centroids were 0.28 @ 179, 0.45 @ 001, 0.37 @ 001, 0.19 @ 003, 0.19 @ 001, and 0.23 @ 178 diopter (D) for the 6 aforementioned methods, respectively (P < .000001 [ORAx, ORAy]). Based on TCP2 measurements, eyes with against-the-rule ACA and with-the-rule (WTR) ACA had ORA centroids of 0.09 @ 082 and 0.58 @ 001 D (P < .000001 [ORAx, ORAy]), respectively. ORA was nonzero and not entirely explained by the cornea, especially in those with WTR ACA. CONCLUSIONS: Total keratometric astigmatism did not explain all ocular astigmatism. Noncorneal contributions were significant, especially in eyes with WTR ACA.

Predictability of Residual Postoperative Astigmatism After Implantation of a Toric Intraocular Lens Using Two Different Calculators.

PURPOSE: To compare predictability of postoperative refractive astigmatism (RA) using the Emmetropic Verifying Optical (EVO) Toric Formula v2.0 to one that accounts only for anterior corneal astigmatism. METHODS: This is a secondary analysis of de-identified data from a clinical trial including 9 sites across the United States. Preoperative biometry was used to predict postoperative RA with the implanted toric IOL using legacy enVista and EVO online calculators. The RA prediction error was computed between back-calculated postoperative RA and predicted residual RA. Outcome measures included vector (centroid) and arithmetic mean RA prediction error. RESULTS: Comparison of calculators was based on 109 eyes, 97 (89%) of which were implanted with a toric IOL with an effective astigmatism power of 1.4 D or less. Centroid of the RA prediction errors was 0.37 D @ 178 and 0.17 D @ 090 for the legacy and EVO calculators, respectively (p < 0.0001). The proportion of eyes with an absolute RA prediction error ≤0.5 was 47.3% and 49.1% (p = 0.78), while the proportion of eyes ≤1.0 D was 82.7% and 89.1% (p = 0.03). Differences in the proportions ≤0.5 D existed for WTR (p = 0.015) but not ATR (p = 0.75) eyes. The proportion in which orientation of the predicted RA (ATR, WTR, or oblique) matched the actual RA was 62% and 78% for legacy and EVO calculators, respectively (p = 0.0029). CONCLUSION: The EVO Toric Formula v2.0 out-performed the legacy calculator with regards to predictions in eyes with low astigmatism.