Double-flanged knotless technique for iris prosthesis and IOL implantation associated with keratoplasty.

INTRODUCTION: Anterior segment reconstruction and penetrating keratoplasty combined with iris prosthesis (IP) and intraocular lens (IOL) scleral fixation require prolonged open-sky surgery and complex suturing. Herein we present a novel double-flanged knotless surgical technique that minimizes the open sky duration and facilitates the fixation of the IP and IOL complex to the sclera. METHODS: After corneal trephination and removal, a temporary keratoprosthesis is fixated. Three 5.0 polypropylene suture segments are introduced in the anterior chamber transconjunctivally and then externalized through keratoprosthesis. Each suture is threaded through the eyelets of the IP and then flanged. The temporary keratoprosthesis is removed, and the IP and IOL complex is positioned in the sulcus. A donor cornea button is sutured in place and the IP is centred on the optical axis by adjusting the polypropylene sutures. Finally, the suture ends are shortened, flanged, and buried under the conjunctiva. RESULTS: Surgery was performed on three eyes of three patients. No intraoperative complications occurred, while cystoid macular edema and ocular hypertension occurred in two patients during the follow-up period. The best corrected visual acuity was 6/20, 8/20, and 13/20. So far the IPs remained stable in the three eyes with a maximum follow-up of 18 months. CONCLUSION: This novel technique of penetrating keratoplasty combined with an intraocular lens (IOL) and iris prosthesis implantation makes it possible to reduce open sky surgery time, avoid complex suturing, and ensure optimal IOL visual axis alignment by adjusting suture tension.

Accuracy of Nine Formulas to Calculate the Powers of an Extended Depth-of-Focus IOL Using Two SS-OCT Biometers.

PURPOSE: To evaluate the accuracy of nine formulas to calculate the power of a new extended depth-of-focus intraocular lens (EDOF IOL), the AcrySof IQ Vivity (Alcon Laboratories, Inc), using measurements from two optical biometers, the IOLMaster 700 (Carl Zeiss Meditec AG) and Anterion (Heidelberg Engineering GmbH). METHODS: After constant optimization, the accuracy of these formulas was analyzed in 101 eyes: Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, Olsen, RBF 3.0, and SRK/T. Both standard and total keratometry from the IOLMaster 700 and standard keratometry from the Anterion were used for each formula. RESULTS: Constant optimization provided slightly different values for the A-constant, which ranged between 118.99 and 119.16, depending on the formula and the optical biometer. According to the heteroscedastic test, within each keratometry modality the standard deviation of the SRK/T was significantly higher compared to that of the Holladay 1, Kane, Olsen, and RBF 3.0 formulas. The SRK/T formula provided less accurate results also when the absolute prediction errors were compared by Friedman test. According to McNemar's test with Holm corrections, statistically significant differences were found within each keratometry modality between the percentage of eyes with a prediction error within ±0.25 diopters obtained with the Olsen formula compared to the Holladay 1 and Hoffer Q formulas. CONCLUSIONS: Constant optimization remains a mandatory step to achieve the best outcomes with the new EDOF IOL: the same constant should not be used for all formulas and for both optical biometers. Different statistical tests revealed that older IOL formulas have lower accuracy compared to newer formulas. [J Refract Surg. 2023;39(3):158-164.].

Systematic Preserflo MicroShunt Intraluminal Stenting for Hypotony Prevention in Highly Myopic Patients: A Comparative Study.

Transient hypotony is the most common early complication after Preserflo MicroShunt (PMS) implantation. High myopia is a risk factor for the development of postoperative hypotony-related complications; therefore, it is advisable that PMS implantation in patients should be performed while employing hypotony preventive measures. The aim of this study is to compare the frequency of postoperative hypotony and hypotony-related complications in high-risk myopic patients after PMS implantation with and without intraluminal 10.0 nylon suture stenting. This is a retrospective, case-control, comparative study of 42 eyes with primary open-angle glaucoma (POAG) and severe myopia that underwent PMS implantation. A total of 21 eyes underwent a non-stented PMS implantation (nsPMS), while in the remaining eyes (21 eyes), PMS was implanted with an intraluminal suture (isPMS group). Hypotony occurred in six (28.57%) eyes in the nsPMS group and none in the isPMS group. Choroidal detachment occurred in three eyes in the nsPMS group; two of them were associated with the shallow anterior chamber and one was associated with macular folds. At 6 months after surgery, the mean IOP was 12.1 ± 3.16 mmHg and 13.43 ± 5.22 mmHg (p = 0.41) in the nsPMS and isPMS group, respectively. PMS intraluminal stenting is an effective measure to prevent early postoperative hypotony in POAG highly myopic patients.

Risk of retinal vein occlusion following COVID-19 vaccination: a self-controlled case series.

BACKGROUND: To evaluate the association between COVID-19 vaccination and retinal vein occlusion (RVO). METHODS: This multicentre self-controlled case series included patients with RVO seen in five tertiary referral centres in Italy. All adults who received at least one dose of the BNT162b2, ChAdOx1 nCoV-19, mRNA-1273 or Ad26.COV2.S vaccine and had a first diagnosis of RVO between January 01, 2021, and December 31, 2021 were included. Incidence rate ratios (IRRs) of RVO were estimated using Poisson regression, comparing rates of events in a 28-day period following each dose of vaccination and in the unexposed control periods. RESULTS: 210 patients were included in the study. No increased risk of RVO was observed after the first dose (1-14 days IRR: 0.87, 95% CI: 0.41-1.85; 15-28 days IRR: 1.01, 95% CI: 0.50-2.04; 1-28 days IRR: 0.94, 95% CI: 0.55-1.58) and second dose of vaccination (1-14 days IRR: 1.21, 95% CI: 0.62-2.37; 15-28 days IRR: 1.08, 95% CI: 0.53-2.20; 1-28 days IRR: 1.16, 95% CI: 0.70-1.90). No association between RVO and vaccination was found in subgroup analyses by type of vaccine, gender and age. CONCLUSIONS: This self-controlled case series found no evidence of an association between RVO and COVID-19 vaccination.

Comparison of the new Hoffer QST with 4 modern accurate formulas.

PURPOSE: To investigate the new Hoffer QST (Savini/Taroni) formula (HQST) and compare it with the original Hoffer Q (HQ) and 4 latest generation formulas. SETTING: I.R.C.C.S.-G.B. Bietti Foundation, Rome, Italy. DESIGN: Retrospective case series. METHODS: Refractive outcomes of the HQST, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, HQ, Kane, and Radial Basis Function (RBF) 3.0 formulas were compared. Subgroup analysis was performed in short (<22 mm) and long (>25 mm) axial length eyes. The SD of the prediction error (PE) was investigated using the heteroscedastic method. RESULTS: 1259 eyes of 1259 patients divided in a White group (n=696), implanted with the AcriSof SN60AT (Alcon Labs), and an Asian group (n=563), implanted with the SN60WF (Alcon Labs), were investigated. In the Asian group, the heteroscedastic method did not disclose any significant difference among the SD of the 4 modern formulas (range from 0.333 to 0.346 D), whereas the SD of the HQ formula (0.384 D) was significantly higher. Compared with the original HQ formula, in both White and Asian groups, the HQST formula avoided the mean myopic PE in short eyes and the mean hyperopic PE in long eyes. CONCLUSIONS: The new HQST formula was superior to the original HQ formula and reached statistical and clinical results comparable with those achieved by the BUII, EVO, Kane, and RBF formulas.

Ab-externo intraluminal stent for prolonged hypotony and choroidal detachment after Preserflo implantation.

PURPOSE: To describe a case of prolonged hypotony and choroidal detachment following insertion of a Preserflo™ MicroShunt in a patient with primary open-angle glaucoma (POAG). CASE REPORT: An 84-year-old Caucasian man with medically uncontrolled POAG developed refractory hypotony and choroidal detachment following a mitomycin C augmented Preserflo MicroShunt (PMS) insertion. Initial medical treatment with Dexamethasone 2 mg/mL and Atropine 1% for the hypotony (4 mmHg) and choroidal detachment was unsuccessful, BCVA decreased from the preoperative 20/28 to 20/60. After 90 days, surgery revision was carried out by inserting a 10-0 nylon monofilament suture through the distal end of the PMS reaching the opposite end of the tube. The free end of the nylon suture was exposed from the conjunctiva in the inferotemporal quadrant close to the fornix to ensure access to the occlusive stent. After one month intraocular pressure (IOP) was 7 mmHg, the choroidal detachment was completely regressed, and best corrected visual acuity (BCVA) increased to 20/28, at that time the exposed part of the stent was trimmed. 6 months after the revision surgery IOP was 14 mmHg, BCVA was 20/25, and the nylon stent was retained side to side inside the PMS lumen. CONCLUSION: The management of hypotony and choroidal detachment after a glaucoma drainage device (GDD) implantation is still unstandardized. The ab externo insertion of a nylon suture grants multiple advantages over the other techniques when performed on a PMS tube.

Repeatability of new optical biometer and agreement with 2 validated optical biometers, all based on SS-OCT.

PURPOSE: To evaluate the repeatability of the measurements provided by a new optical biometer (EyeStar 900) based on swept-source optical coherence tomography (SS-OCT) and their agreement with the measurements given by 2 validated biometers based on the same technology, the IOLMaster 700 and Argos. SETTING: IRCCS G.B. Bietti Foundation, Rome, Italy. DESIGN: Prospective evaluation of diagnostic test. METHODS: In a series of unoperated eyes, 3 consecutive scans were acquired with the EyeStar 900, and 1 with the IOLMaster 700 and the Argos. The following biometry parameters were analyzed: axial length (AL), keratometry (K), corneal astigmatism, central corneal thickness, corneal diameter (CD), anterior chamber depth (ACD), lens thickness (LT), and lens tilting. Repeatability was assessed using test-retest variability, the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC); agreement was based on the 95% limits of agreement. RESULTS: 56 eyes of 56 patients were analyzed. High repeatability was achieved for all measured parameters, as the CoV was <1% in most cases and ICC was >0.95 for all parameters. Good to high agreement was found among the measurements of the 3 optical biometers, although some statistically significant differences were detected between the EyeStar 900 and Argos (mean K, ACD, LT, and CD were higher with the Argos). The Argos measured a shorter AL in eyes >25 mm. CONCLUSIONS: The new generation SS-OCT EyeStar 900 optical biometer produces highly repeatable measurements that are in good agreement with those provided by 2 previously validated instruments.

IOL Power Calculation in Eyes Undergoing Combined Descemet Membrane Endothelial Keratoplasty and Cataract Surgery.

PURPOSE: To assess the accuracy of different corneal powers for intraocular (IOL) power calculation in combined Descemet membrane endothelial keratoplasty (DMEK) and cataract surgery and investigate whether preoperative parameters correlate to the prediction error (PE). METHODS: This prospective case series involved patients with Fuchs endothelial dystrophy receiving combined DMEK and cataract surgery. Preoperatively, patients underwent optical biometry and anterior segment OCT (AS-OCT). AS-OCT measurements were repeated 6 months postoperatively, when final refraction was assessed. The PE was calculated using the preoperative average keratometry (Kave) measured by the optical biometer and User Group for Laser Interference Biometry (ULIB) constants. It was also calculated, after constant optimization, using the preoperative Kave from both devices and the total corneal power (TCP) measured by AS-OCT, as well as the postoperative Kave and TCP measured by AS-OCT. RESULTS: ULIB constants resulted in the highest hyperopic PE (P < .0001). Constant optimization improved the results, because the PE was zeroed out and the absolute PEs decreased. No significant difference was found among the Barrett Universal II, Emmetropia Verifying Optical 2.0, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas. Further improvement was achieved with the postoperative Kave and TCP, although the accuracy remained moderate. The PE based on preoperative corneal measurements was correlated to the amount of corneal flattening; the latter could be predicted by multiple linear regression accounting for anterior and posterior corneal radii (P = .0002) and was correlated to the preoperative anterior/posterior ratio. CONCLUSIONS: Constant optimization is beneficial for combined DMEK and phacoemulsification. Predicting postoperative corneal flattening may improve the results of IOL power accuracy. [J Refract Surg. 2022;38(7):435-442.].

Corneal diameter measurements by 3 optical biometers and their effect on phakic intraocular lens sizing.

PURPOSE: To compare phakic intraocular lens size calculations based on corneal diameter (CD) measurements by 3 instruments. SETTING: G.B. Bietti Foundation I.R.C.C.S., Rome, Italy. DESIGN: Retrospective interventional case series. METHODS: Preoperatively, CD was measured with the Aladdin, IOLMaster 700, and Pentacam AXL Wave. The simulated ICL size was computed by entering CD measurements into the manufacturer's calculator. Postoperatively, vaulting was measured by anterior segment optical coherence tomography. The optimal ICL size (OIS) was calculated and compared with the commercially available OIS (CAOIS). RESULTS: 54 eyes (29 patients) with the implantable collamer lens (ICL) were enrolled. The mean CD was 12.02 ± 0.36 mm with the Aladdin, 12.35 ± 0.39 mm with the IOLMaster 700, and 12.22 ± 0.41 mm with the Pentacam AXL Wave ( P &lt; .0001), with the closest agreement between the Pentacam AXL Wave and IOLMaster 700 (95% limits of agreement: -0.43 to +0.17 mm). Vaulting (mean: 558 ± 261 µm) was within 251 and 1000 µm in 49 eyes (83.3%). The mean difference between the simulated ICL size and OIS ranged between -0.11 ± 0.35 mm and 0.10 ± 0.30 mm ( P &lt; .0001), with no statistically significant difference between the IOLMaster 700 and Pentacam AXL Wave. The simulated ICL size was equal to CAOIS in 38 eyes (70.37%) with the Aladdin, 37 eyes (68.52%) with the IOLMaster 700, and 39 eyes (72.22%) with the Pentacam AXL Wave, without any statistically significant difference. CONCLUSIONS: CD measurements by the 3 devices lead to similar percentages of eyes with an ICL size equal to the OIS. Agreement is closer between the IOLMaster 700 and Pentacam AXL Wave.

Comparison of Corneal Power Calculation by Standard Keratometry and Total Keratometry in Eyes With Previous Myopic FS-LASIK.

PURPOSE: To compare the accuracy of Total Keratometry (TK) and standard keratometry (K) with the IOLMaster 700 (Carl Zeiss Meditec) in evaluating the corneal refractive change in eyes with previous myopic femtosecond laser-assisted LASIK (FS-LASIK). METHODS: A series of consecutive patients who had undergone myopic FS-LASIK was prospectively enrolled. The refractive change in spherical equivalent (ΔSE) was defined as the difference between the preoperative target correction entered into the laser software and the postoperative cycloplegic refraction. The difference between the postoperative and the preoperative K (ΔK) and the difference between the postoperative and the preoperative TK (ΔTK) were compared to the ΔSE. Only the right eye of each patient was selected for the statistical analysis. RESULTS: Twenty-five eyes of 25 patients were enrolled. The mean ΔSE was -4.41 ± 1.68 diopters (D). The mean ΔK (-3.82 ± 1.60 D) revealed a statistically significant underestimation of the laser-induced refractive change (P < .0001), whereas the mean ΔTK (-4.36 ± 1.78 D) did not show any significant difference (P = .45). The difference between ΔK and ΔTK was statistically significant (P < .0001). Linear regression between the laser-induced refractive change and the individual difference between the postoperative K and TK disclosed a statistically significant relationship (r = -0.6930, r2 = 0.4803, P < .0001), thus revealing that higher refractive corrections increase the difference between the postoperative values of K and TK. CONCLUSIONS: TK does not underestimate the laser-induced corneal changes and can be considered a reliable option for intraocular lens power calculation after myopic excimer laser surgery. [J Refract Surg. 2021;37(12):848-852.].

Accuracy of New Intraocular Lens Power Calculation Formulas: A Lens Thickness Study.

PURPOSE: To investigate whether using lens thickness measurement as an optional input improves the refractive accuracy of four new generation formulas. METHODS: Consecutive patients scheduled for cataract surgery were enrolled. Preoperative biometry was performed with an OA-2000 optical biometer (Tomey). All patients received the same monofocal intraocular lens (AcrySof SN-60WF; Alcon Laboratories, Inc). The Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), Kane, and Radial Basis Function (RBF) formulas were analyzed with and without the inclusion of lens thickness as an input. Postoperative refraction was measured at 1 month. The mean prediction error (PE), the median absolute error (MedAE), and the percentage of eyes with a PE within ±1.00 diopters (D) or less were calculated after constant optimization. RESULTS: The final analysis was performed on 169 eyes of 169 patients. Comparison of the mean PE, MedAE, and the percentage of eyes with a PE within ±0.25, ±0.50, ±0.75, and ±1.00 D resulting from each formula with and without lens thickness did not reveal any statistically significant difference. Cochran's Q test showed a statistically significant difference among formulas in the percentage of eyes with a PE of less than ±0.50 D (P = .042). However, Dunn's post-hoc test did not show any statistically significant difference between any pair of formulas. CONCLUSIONS: Lens thickness measurement did not improve the accuracy of the BUII, EVO, Kane, or RBF formulas. The RBF formula yielded the same results with and without lens thickness, thus making this input useless. [J Refract Surg. 2021;37(3):202-206.].