Refractive surgical approaches to keratoconus: A systematic review and network meta-analysis

Advancements in diagnostic methods and surgical techniques for keratoconus (KC) have increased non-invasive treatment options. Successful surgical planning for KC involves a combination of clinical science, empirical evidence, and surgical expertise. Assessment of disease progression is crucial, and halting the progression should be the focus if it is progressive. While surgeons used to rely on experience alone to decide the surgical method, comparing the network of primary factors, such as visual acuity, across studies can help them choose the most appropriate treatments for each patient and achieve optimal outcomes. Meticulous tabulation methods facilitate interpretation, highlighting the importance of selecting the correct surgical and rehabilitation approach based on each patient's condition and stage of the disease. We detail the outcomes of a comprehensive network meta-analysis comparing the effectiveness of various combined therapeutic refractive treatments for KC at identical stages of the disease, spanning four distinct follow-up intervals. Additionally, the comprehensive analysis suggests that for corneas with optimal best corrected visual acuity (BCVA) preoperatively (classified as regular), combining phakic intraocular lenses with intracorneal ring segments (ICRS) and corneal cross-linking (CXL) could offer the best therapeutic approach provided the disease stage does not exceed stage 3. For irregular corneas, although initial follow-ups show a significant difference in BCVA with surface ablation, longer-term follow-ups recommend combining surface ablation with ICRS and CXL, especially at higher stages.

Differences Between Keratometry and Total Keratometry Measurements in a Large Dataset Obtained With a Modern Swept Source Optical Coherence Tomography Biometer

PURPOSE

This study aimed to explore the concept of total keratometry (TK) by analyzing extensive international datasets representing diverse ethnic backgrounds. The primary objective was to quantify the disparities between traditional keratometry (K) and TK values in normal eyes and assess their impact on intraocular lens (IOL) power calculations using various formulas.

DESIGN

Retrospective multicenter intra-instrument reliability analysis.

METHODS

The study involved the analysis of biometry data collected from ten international centers across Europe, the United States, and Asia. Corneal power was expressed as equivalent power and astigmatic vector components for both K and TK values. The study assessed the influence of these differences on IOL power calculations using different formulas. The results were analyzed and plotted using Bland-Altman and double angle plots.

RESULTS

The study encompassed a total of 116,982 measurements from 57,862 right eyes and 59,120 left eyes. The analysis revealed a high level of agreement between K and TK values, with 93.98% of eyes exhibiting an absolute difference of 0.25 D or less. Astigmatism vector differences exceeding 0.25 D and 0.50 D were observed in 39.43% and 1.08% of eyes, respectively.

CONCLUSIONS

This large-scale study underscores the similarity between mean K and TK values in healthy eyes, with rare clinical implications for IOL power calculation. Noteworthy differences were observed in astigmatism values between K and TK. Future investigations should delve into the practicality of TK values for astigmatism correction and their implications for surgical outcomes.

Influence of sutureless scleral fixation techniques with 3-piece IOLs on dislocation force

PURPOSE

To compare four different secondary IOL fixation techniques regarding the least required force to dislocate a scleral fixated 3-piece IOL in human corneoscleral donor tissue (CST).

DESIGN

Experimental Laboratory investigation METHODS: The least required dislocation force (LRDF) of four different secondary IOL fixation techniques, namely the techniques using transscleral tunnels (TT, as described by Scharioth), glued haptics (GH, Argawa), flanged haptics (FH, Yamane) and bent haptic ends (BH, Behera/Bolz) were investigated using 40 three-piece IOLs (Sensar AR40) fixated to human scleral tissue. The main outcome of the study, dislocation force between different techniques, was measured with a tensiometer.

RESULTS

The dislocation force needed to dislocate the haptics was highest with the FH technique and was significantly higher than with all the other techniques (GH vs FH: -1.02±0.02 N, p<0.001; TT vs FH: -1.08±0.21 N, p<0.001; BH vs FH: -1.00±0.25 N, p=0.044). There was no significant difference regarding the dislocation force between the other techniques (GH vs TT (-0.06±0.100 N, p=0.988), GH vs BH (-0.02±0.03 N, p=0.60), TT vs BH (-0.08±0.04 N, p=1.000).

CONCLUSIONS

The flange haptic technique as described by Yamane proved to be the strongest form of secondary IOL fixation regarding dislocation force in this in vitro study. The other fixation techniques showed significantly less resistance to axial traction.

Quality assurance via telephone interviews after cataract surgery: An explorative study

INTRODUCTION

Cataract surgery is a relatively safe procedure with satisfactory postoperative results in most patients. However, in rare cases severe complications can occur shortly after the intervention. Therefore, patients are advised to undergo an ophthalmological examination postoperatively, which should be performed as soon as possible in case of emergencies. However, exactly when these follow-up visits should take place is still discussed. A time- and cost-saving alternative to this could be short-term postoperative telemedical approaches. The aim of this study was to analyze patient complaints as well as satisfaction with and the best timepoint to perform telephone calls after cataract surgery.

METHODS

Patients scheduled for cataract surgery received a telephone call on the surgery day or the day after (study group) during which they were asked about complaints or additional examination visits. Patients without telephone calls served as control group. All patients had a follow-up visit one week after the intervention during which a questionnaire was filled out and the study group was asked about their satisfaction with the telephone calls.

RESULTS

181 patients were recruited in this study. Ocular surface problems were the most common postoperative symptom. More than 80% of the patients were very satisfied with the telephone calls, with patients being contacted on the day of surgery being more calmed than those called on the next day. No difference in additional and planned follow-up visits was found between the study and the control group (P > .40). Postoperative patient complaints (Phi 0.372, P < .001) and additional prescribed therapy (Phi 0.480, P < .001) were moderately associated with additional visits.

CONCLUSION

Satisfaction with telephone reviews shortly after cataract surgery was very high and contacting patients on the evening of the day of the procedure could be a time- and cost-saving alternative to short-term in-house follow-up visits.

Dislocation force of scleral flange-fixated intraocular lens haptics

PURPOSE

To measure the dislocation forces in relation to haptic material, flange size and needle used.

SETTING

Hanusch Hospital, Vienna, Austria.

DESIGN

Laboratory Investigation.

METHODS, MAIN OUTCOME MEASURES

30 G (gauge) thin wall and 27 G standard needles were used for a 2 mm tangential scleral tunnel in combination with different PVDF (polyvinylidene fluoride) and PMMA (polymethylmethacrylate haptics). Flanges were created by heating 1 mm of the haptic end, non-forceps assisted in PVDF and forceps assisted in PMMA haptics. The dislocation force was measured in non-preserved cadaver sclera using a tensiometer device.

RESULTS

PVDF flanges achieved were of a mushroom-like shape and PMMA flanges were of a conic shape. For 30 G needle tunnels the dislocation forces for PVDF and PMMA haptic flanges were 1.58 ± 0.68 N (n = 10) and 0.70 ± 0.14 N (n = 9) (p = 0.003) respectively. For 27 G needle tunnels the dislocation forces for PVDF and PMMA haptic flanges were 0.31 ± 0.35 N (n = 3) and 0.0 N (n = 4), respectively. The flange size correlated with the occurring dislocation force in experiments with 30 G needle tunnels (r = 0.92), when flanges were bigger than 384 micrometres.

CONCLUSIONS

The highest dislocation forces were found for PVDF haptic flanges and their characteristic mushroom-like shape for 30 G thin wall needle scleral tunnels. Forceps assisted flange creation in PMMA haptics did not compensate the disadvantage of PMMA haptics with their characteristic conic shape flange.

Reducing ophthalmic surgical waste through electronic instructions for use: a multisociety position paper

Every ophthalmic surgical supply, including intraocular lenses (IOLs), IOL cartridges, and ophthalmic viscosurgical device syringes, is packaged with instructions for use (IFU). These pamphlets are printed in multiple languages and, in the case of an IOL, significantly increase the size and weight of the packaging. To eliminate this significant and unnecessary source of waste, we recommend that manufacturers move to Quick Response codes that link to online electronic IFU (e-IFU) as a sensible alternative. In addition to reducing carbon emissions and manufacturing costs, e-IFU can be updated more easily and accessed by surgeons in the clinic, where IOL models and powers are selected. Varying and inconsistent IFU requirements between different countries are a barrier to wider adoption of e-IFU by the ophthalmic surgical industry. Regulatory agencies in every country should allow and encourage e-IFU. This position paper has been endorsed by the 3 major societies that sponsor EyeSustain, a consortium of global societies dedicated to advancing sustainability in ophthalmology.

Attaining the optimal flange technique for transscleral capsular bag stabilization using iris hooks

PURPOSE

To investigate the flange properties of different iris hooks.

SETTING

Vienna Institute for Research in Ocular Surgery (VIROS), Hanusch Hospital, Vienna, Austria.

DESIGN

Laboratory study.

METHODS

The flanging properties of 4 different iris hooks made from polypropylene (PP), elastic polymer (EP), and nylon were investigated with different heating distances and both with and without forceps gripping. The maximum diameter of the flanges was measured, and the shape of the flanges was evaluated.

RESULTS

Although both nylon and EP iris hooks had too small flange diameters for intrascleral fixation, PP iris hooks had a sufficient flange diameter (>330 μm) and mushroom-like shape. Furthermore, in PP hooks, heating distance was directly proportional to flange diameter.

CONCLUSIONS

The findings of this study suggest that only PP iris hooks are suitable for flanged intrascleral fixation, which is off-label, to secure adequate fixation.

Rotational stability and capsular bag performance of a hydrophobic acrylic open-loop single-piece intraocular lens

PURPOSE

To evaluate the rotational stability and capsular bag performance of a blue light-absorbing hydrophobic acrylic open-loop single-piece intraocular lens (IOL) with a blast-finished anchor wing haptic design during the first 6 postoperative months.

METHODS

In this prospective clinical study, patients with age-related cataract and potential postoperative corrected distance visual acuity (CDVA) of 0.2 logMAR or better were included. The patients received a non-toric hydrophobic acrylic single-piece IOL with an axis mark (YST0.00; Nidek Co. Ltd, Japan). Surgeries were video-taped. Retroillumination images were acquired 1 h, 1 week and 6 months postoperatively. Rotational stability was assessed by precise image overlay. At 6 months, Purkinje meter measurements were performed to evaluate tilt and decentration.

RESULTS

In total, 100 eyes of 77 patients were included in the analysis. Mean absolute rotation was 2.1 ± 1.7° (median 1.7, range: 0-7.9) at 6 months (1 h - 6 months postoperatively). IOL rotation was ≤3° and ≤6° in 74 (74%) and 98 (98%) eyes, respectively. Mean absolute IOL rotation from the end of surgery to 6 months was 2.5 ± 2.2° (median 2.3, range: 0-15.6; n = 78). Mean tilt (pupillary axis) and decentration were 4.1 ± 1.9° (median 4.0, range: 0.5-8.2) and 0.35 ± 0.17 mm (median 0.32, range: 0.06-0.91) respectively (n = 84). Postoperatively, 98 (98%) eyes achieved a CDVA of 0.2 logMAR or better, 95 (95%) of ≤0.1 and 81 (81%) of ≤0.0.

CONCLUSIONS

This hydrophobic acrylic single-piece IOL showed an excellent rotational stability and capsular bag position with low tilt and decentration values.

Repeatability of biometry in patients with meibomian gland dysfunction before and after vectored thermal pulsation therapy: A randomized, controlled trial

PURPOSE

To evaluate the effect of vectored thermal pulsation therapy (VTPT) on the repeatability of biometry readings of two different optical biometers in patients with meibomian gland dysfunction (MGD).

METHODS

Patients affected by MGD were included in this prospective, randomized, controlled, investigator-masked study. One eye was randomized to VTPT (LipiFlow®, Johnson & Johnson), and the contralateral eye served as a control. Three visits were scheduled at baseline, 2 weeks and 3 months after the treatment. The main outcome parameter of the study was the repeatability of three calculations of emmetropic intraocular lens power (EIOLP) at the 3 months visit as compared to baseline using an optical biometer (IOLMaster® 700, Carl Zeiss Meditec AG). Repeatability of different keratometry values obtained by the optical biometer and a Placido-disc topographer (MS-39®, CSO) served as secondary outcome parameters.

RESULTS

Twenty-nine patients were included in the final analysis. While tear film parameters improved in the study eyes, there were no significant differences regarding the repeatability of three EIOLP measurements between baseline and 3-months-visit in both eyes (p > 0.05) and keratometry measurements in both the optical biometer and the Placido-disc topographer. Remarkably, throughout all study visits, there were some outliers regarding the repeatability of measurements.

CONCLUSION

While both devices showed high repeatability regarding EIOLP and keratometry, future studies are needed to detect high-risk patients for poor repeatability.

Foveal-Sparing ILM Peeling with ILM Flap Transposition over the Macular Hole for Repair of Full-Thickness Macular Holes

BACKGROUND

Full-thickness macular holes, defined as full-thickness defects of the fovea, lead to central scotoma and deterioration of vision. Apart from peeling of the internal limiting membrane (ILM), ILM flap techniques have been reported to have potential in improving results in macular hole surgery. In addition, foveal-sparing ILM peeling gives a high macular hole closure rate and improvement in postoperative visual acuity. The aim of this study was to examine outcomes in a cohort of patients with full-thickness macular holes that underwent vitrectomy with foveal-sparing ILM peeling and transposition of an ILM flap over the macular hole.

METHODS

This retrospective study included patients scheduled for pars plana vitrectomy with foveal-sparing ILM peeling, combined with ILM flap transposition over the macular hole, for macular hole repair. All patients received a gas tamponade with 20% sulphur hexafluoride and were encouraged to undergo postoperative face-down positioning for 48 hours after surgery. Optical coherence tomography (OCT) imaging of the macula and distance-corrected visual acuity (DCVA) were performed before and 3 months after surgery.

RESULTS

In total, 42 eyes of 42 patients were included in this study. Leaving a broad area of residual ILM at the foveal rim led to a high risk of failure in macular hole closure, while leaving a narrow zone of residual ILM at the foveal rim resulted in high macular hole closure rates (97% type 1 closure and 3% type 2 closure), with a median improvement of DCVA of 4 lines [interquartile range (IQR): 3 to 6] among pseudophakic and 3.5 lines (IQR: 2 to 5) among phakic patients.

CONCLUSIONS

A combination of foveal-sparing ILM peeling with ILM flap techniques was shown to be a safe and effective surgical option for patients with full-thickness macular holes, resulting in a high macular hole closure rate and improvement in visual acuity in the majority of patients.

Online intraocular lens calculation

PURPOSE OF REVIEW

To showcase the majority of online intraocular lens (IOL) calculation tools and highlight some of their characteristics.

RECENT FINDINGS

Online tools are available for preoperative and postoperative IOL-related calculations, including IOL power and toricity selection for standard patients, patients who underwent prior refractive surgery, keratoconus, limbal relaxing incisions for astigmatism management, realignment of a misplaced or rotated toric IOL, surgical induced astigmatism (SIA), formulae comparison, and other tools.

SUMMARY

As there are new online developments and technology is advancing rapidly, we hope that this review will assist ophthalmologists in becoming acquainted with a large variety of online tools.

Keratoconus: exploring fundamentals and future perspectives - a comprehensive systematic review

Background

New developments in artificial intelligence, particularly with promising results in early detection and management of keratoconus, have favorably altered the natural history of the disease over the last few decades. Features of artificial intelligence in different machine such as anterior segment optical coherence tomography, and femtosecond laser technique have improved safety, precision, effectiveness, and predictability of treatment modalities of keratoconus (from contact lenses to keratoplasty techniques). These options ingrained in artificial intelligence are already underway and allow ophthalmologist to approach disease in the most non-invasive way.

Objectives

This study comprehensively describes all of the treatment modalities of keratoconus considering machine learning strategies.

Design

A multidimensional comprehensive systematic narrative review.

Data sources and methods

A comprehensive search was done in the five main electronic databases (PubMed, Scopus, Web of Science, Embase, and Cochrane), without language and time or type of study restrictions. Afterward, eligible articles were selected by screening the titles and abstracts based on main mesh keywords. For potentially eligible articles, the full text was also reviewed.

Results

Artificial intelligence demonstrates promise in keratoconus diagnosis and clinical management, spanning early detection (especially in subclinical cases), preoperative screening, postoperative ectasia prediction after keratorefractive surgery, and guiding surgical decisions. The majority of studies employed a solitary machine learning algorithm, whereas minor studies assessed multiple algorithms that evaluated the association of various keratoconus staging and management strategies. Last but not least, AI has proven effective in guiding the implantation of intracorneal ring segments in keratoconus corneas and predicting surgical outcomes.

Conclusion

The efficient and widespread clinical translation of machine learning models in keratoconus management is a crucial goal of potential future approaches to better visual performance in keratoconus patients.

Trial registration

The article has been registered through PROSPERO, an international database of prospectively registered systematic reviews, with the ID: CRD42022319338.

Immediate sequential vs delayed sequential bilateral cataract surgery: systematic review and meta-analysis

The main aim of this systematic review and meta-analysis was to evaluate the safety and efficacy profile of immediate sequential bilateral cataract surgery (ISBCS) compared with delayed sequential bilateral cataract surgery (DSBCS). MEDLINE Ovid, EMBASE, and CENTRAL databases were searched. Outcome measures were postoperative visual acuity, postoperative spherical equivalent (refractive outcome), endophthalmitis, corneal edema, pseudophakic macular edema, and posterior capsule rupture (PCR). 13 articles met criteria for final inclusion. A total of 11 068 622 participants (18 802 043 eyes) were included. No statistically significant differences between ISBCS and DSBCS were identified in all the postoperative outcomes evaluated. However, a higher risk for PCR was identified in the ISBCS group from the pooled analysis of nonrandomized studies (risk ratio, 1.34, 95% CI, 1.08-1.67, P = .0081). In our view, the ISBCS approach has an acceptable safety-efficacy profile, comparable with DSBCS. Future investigations are warranted, with a focus on the analysis of risk factors for surgical complications, patient-reported outcome-measures, and cost effectiveness.

Occurrence of Corneal Staining after Cataract Surgery with and without Chitosan-N-Acetylcysteine Eye Drops

INTRODUCTION

The objective of this study was to evaluate the prevalence of ocular surface damage assessed by corneal staining scores right after cataract surgery and whether it can be prevented using chitosan-N-acetylcysteine (C-NAC) eye drops.

METHODS

We included patients scheduled for routine cataract surgery. Each patient was randomly assigned to one of three groups. Patients in group 1 underwent routine cataract surgery with no additional eye drops. In group 2, patients received C-NAC eye drops after cataract surgery, and in group 3, C-NAC was applied both before and after surgery. Both groups continued the treatment once daily for 4 days. Ocular surface alteration was assessed using the National Eye Institute (NEI) score, and the visual analog scale (VAS) was used to evaluate subjective complaints.

RESULTS

Thirty-six patients were included in the final analyses. One hour after cataract surgery, a statistically significant increase in corneal fluorescein staining was observed in all groups, which decreased again after 1 week. There was no significant difference between the groups 1 h after cataract surgery, though a tendency toward lower NEI scores was observed during this time point in group 3.

DISCUSSION

Cataract surgery induced ocular surface staining and subjective complaints after 1 h. However, the increase in VAS score was small and probably not clinically relevant. The application of perioperative C-NAC eye drops did reduce the rate of corneal staining after cataract surgery in a clinically relevant manner.

Effect of Air Tamponade among Patients with Epiretinal Membranes and Intraretinal Cystoid Changes Undergoing Vitrectomy with Membrane Peeling - A Prospective Randomized Trial

BACKGROUND

The effect of air tamponade among patients undergoing vitrectomy with membrane peeling for removal of epiretinal membranes (ERM) is controversially discussed. The aim of the present study was to analyze differences in outcomes between air tamponade and balanced salt solution (BSS) in a study population with preoperative intraretinal cystoid changes.

PATIENTS AND METHODS

This randomized study included patients scheduled for pars plana vitrectomy with membrane peeling owing to ERM and intraretinal cystoid changes. Air tamponade or BSS at the end of surgery was applied according to preoperative randomization. Optical coherence tomography and best-corrected distance visual acuity (DCVA) measurements were performed before surgery, 5 days after surgery, and 3 months after surgery.

RESULTS

From 96 patients included, 85 eyes had full follow-up and could be included for analysis. Median improvement of DCVA was + 16 EDTRS letters (IQR: 8 to 22) among patients with BSS, while it was + 13 EDTRS letters (IQR: 8 to 17) among patients with air tamponade. There was a trend for better improvement of DCVA when BSS was left at the end of surgery, compared to air tamponade, but not reaching statistical significance.

CONCLUSIONS

There were no statistically significant differences concerning resorption of preoperative intraretinal cystoid changes, improvement of visual acuity, and final DVCA between air tamponade and BSS.

Diagnostic Reliability of Optical Coherence Tomography Biomarkers for Postsurgical Success in Visual Acuity in Patients with Idiopathic Epiretinal Membranes

INTRODUCTION

Several optical coherence tomography (OCT) biomarkers for postsurgical success in patients with idiopathic epiretinal membranes (iERMs) have been described in single predictor analyses. The aim of this study was to assess the reliability of diagnosis of OCT biomarkers and to calculate their impact on postsurgical visual acuity by applying multiple regression analysis.

METHODS

This retrospective study included patients scheduled for pars plana vitrectomy with membrane peeling for iERMs. Presurgical OCT scans were analyzed for the presence of OCT biomarkers by two reviewers. Intra- and interobserver reliability was calculated with the Kuder-Richardson 20 test.

RESULTS

Among the 136 patients included, intra-/interobserver reliability of the OCT biomarkers was 0.89/0.70 for ectopic inner foveal layer (EIFL), 0.82/0.53 for disorganization of retinal inner layer (DRIL), 0.93/0.89 for intraretinal cystoid changes, 0.84/0.78 for alterations of the ellipsoid zone, 0.84/0.72 for cotton ball sign, 0.68/0.58 for hyperreflective foci, 0.55/0.47 for epimacular membrane rips (EMM-rips), and 0.87/0.60 for retinal contraction. Only DRIL and central subfield macular thickness (CMT) were significant predictors for BCVA 3 months after surgery in a multiple regression analysis.

CONCLUSION

Intraobserver reliability of OCT biomarkers was higher than interobserver reliability, reflecting both clinical and grading experience with respect to OCT biomarker evaluation. DRIL and CMT were shown to be significant predictors in a multiple regression analysis, with potential for negative influence on final BCVA after vitrectomy with membrane peeling for iERMs.

Keratoconus Diagnosis: From Fundamentals to Artificial Intelligence: A Systematic Narrative Review

The remarkable recent advances in managing keratoconus, the most common corneal ectasia, encouraged researchers to conduct further studies on the disease. Despite the abundance of information about keratoconus, debates persist regarding the detection of mild cases. Early detection plays a crucial role in facilitating less invasive treatments. This review encompasses corneal data ranging from the basic sciences to the application of artificial intelligence in keratoconus patients. Diagnostic systems utilize automated decision trees, support vector machines, and various types of neural networks, incorporating input from various corneal imaging equipment. Although the integration of artificial intelligence techniques into corneal imaging devices may take time, their popularity in clinical practice is increasing. Most of the studies reviewed herein demonstrate a high discriminatory power between normal and keratoconus cases, with a relatively lower discriminatory power for subclinical keratoconus.

Comparison of corneal aberrations from anterior segment swept source OCT versus Placido-topography combined spectral domain OCT in cataract patients

BACKGROUND

To comprehensively evaluate the agreement of component corneal aberrations from the newly updated wavefront analysis software of a swept-source optical coherence tomographer (SS-OCT) and a referential Placido-topography combined OCT device in elderly cataract patients.

METHODS

Retrospective study including 103 eyes from 103 elderly patients scheduled for cataract surgery that were measured on the same day with a SS-OCT (Heidelberg Engineering, Germany) device and a Placido-topography combined OCT device (CSO, Italy). Anterior, total, and posterior corneal wavefront aberrations were evaluated for their mean differences and limits of agreement (LoA) via Bland-Altman plots. Vector analysis was additionally employed to compare corneal astigmatism measurements in dioptric vector space.

RESULTS

Mean differences of all corneal aberrometric parameters did not exceed 0.05 μm. Total corneal aberrations were not significantly different from 0 except for vertical coma (- 0.04 μm; P = 0.003), spherical aberration (- 0.01 μm, P < 0.001), and root mean square (RMS) higher-order aberration (HOA) (0.03 μm, P = 0.04). The 95% LoA for total corneal aberration parameters between both devices were - 0.46 to 0.42 μm for horizontal astigmatism, - 0.37 to 0.41 μm for oblique astigmatism, - 0.19 to 0.17 μm for oblique trefoil, - 0.33 to 0.25 μm for vertical coma, - 0.20 to 0.22 μm for horizontal coma, - 0.22 to 0.20 μm for horizontal trefoil, - 0.11 to 0.08 μm for spherical aberration, and - 0.22 to 0.28 μm for RMS HOA. Vector analysis revealed no statistically significant mean differences for anterior, total, and posterior corneal astigmatism in dioptric vector space.

CONCLUSION

In eyes undergoing cataract surgery with a regular elderly cornea, corneal wavefront analysis from the SS-OCT device showed functional equivalency to the reference device. Nevertheless, clinically relevant higher order aberration parameters should be interpreted with caution for surgical decision-making.

Effect of Treatment with Topical Azithromycin or Oral Doxycycline on Tear Film Thickness in Patients with Meibomian Gland Dysfunction: A Randomized Controlled Trial

Purpose: This prospective, randomized, observer-masked, parallel-group study aimed to compare the effect of topical azithromycin and oral doxycycline on tear film thickness (TFT) and signs and symptoms of ocular surface disease (OSD) in patients with meibomian gland dysfunction (MGD). Methods: Patients were randomized to either receive topical azithromycin or oral doxycycline. After a baseline visit, three follow-up visits at intervals of 2 weeks were scheduled. Main outcome of the study was change in TFT as measured with ultrahigh resolution optical coherence tomography. Results: Twenty patients were included in the analysis. TFT significantly increased in both groups (P = 0.028 vs. baseline) with no difference between the groups (P = 0.096). As secondary outcomes, ocular surface disease index (OSDI) score and composite signs of OSD significantly decreased in both groups (P = 0.023 for OSDI and P = 0.016 for OSD signs vs. baseline). While eye-related adverse events (AEs) occurred more frequently in the azithromycin group, systemic AEs were more common in the doxycycline group. Conclusions: Both treatments improved signs and symptoms of OSD in patients with MGD with no difference between the groups. Due to the higher frequency of systemic side effects of doxycycline, azithromycin eye drops seem to be an alternative with comparable efficacy. Clinical Trial Registration number: NCT03162497.

Surgeons need to know more about intraocular lens design for accurate power calculation

Improvement in biometry and formulas has raised the bar for accurate intraocular lens (IOL) power calculation. However, when we look closely at the performance of a specific IOL model, we often find that the prediction error varies with the implant power. This phenomenon has no explanation other than that the optic design of the IOL has shifted over the power range, thereby disrupting the assumptions of the calculations. By this report, we call the industry to be more transparent and disclose the basic information about the IOL design that is important for accurate IOL power calculation. The relevant information concerns the refractive index, the central optic thickness, the anterior and posterior curvature radii, the toricity location, the spherical aberration, and haptic angulation. The goal is to predict possible shifts in principal planes or IOL position over the power range causing a refractive surprise if not corrected for.

Rotational stability of a new toric intraocular lens with an advanced optical profile

PURPOSE

To examine the rotational stability of a new toric intraocular lens (IOL), the TECNIS Eyhance Toric II, over a course of 3 months.

SETTING

Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria.

DESIGN

Prospective unmasked single-center study.

METHODS

50 eyes of 50 patients with cataract and regular corneal astigmatism ≥0.75 diopters (D) were included. The TECNIS Eyhance Toric II IOL was implanted in 1 eye of each study patient. Images of the alignment axis of the IOL were taken intraoperatively, as well as at 1 hour, 1 week, and 3 months postoperatively. For the measurement of toric IOL rotation, images were superimposed on the basis of ocular landmarks. Uncorrected and corrected distance (4 m) and intermediate (66 cm) visual acuities were assessed at the 3-month visit.

RESULTS

There was no significant difference in the rotational position between the intraoperative and 3 month timepoints, with a mean rotation of 1.34 ± 1.46 degrees, in 27 examined eyes. ( P = 0.313). No patients had to undergo repositioning of the toric IOL. A significant reduction of refractive cylinder occurred from preoperatively 1.8 ± 1.1 to 0.40 ± 0.42 D at the 3-month visit ( P = .001; n = 43). The corrected distance visual acuity improved significantly from 0.28 ± 0.16 logMAR preoperatively to -0.01 ± 0.13 logMAR at 3 months postoperatively ( P = .001; n = 43).

CONCLUSIONS

The TECNIS Eyhance Toric II showed a good visual performance with no significant rotation over a course of 3 months and, therefore, an excellent rotational stability. The intraocular lens showed a good safety profile with no adverse events.

Potential environmental effect of reducing the variation of disposable materials used for cataract surgery

PURPOSE

To analyze the cataract package variability in 1 country, Austria.

SETTING

Austrian Departments of Ophthalmology.

DESIGN

Cross-sectional study.

METHODS

The cataract package components of 3 different Austrian hospitals were weighed and life cycle assessment on each product performed. This data was then extrapolated to the sales figures of the main Austrian cataract package suppliers to estimate the carbon footprint of all cataract packages used in Austria in 2021.

RESULTS

There were 55 different cataract package compositions in use with an average weight of 0.7 kg. These compositions differ significantly in weight and composition considering that the smallest package was 57% lighter than the largest package. The size of the surgical drapes also showed considerable variation, with a difference of up to 71%. This is substantial, considering that drapes and covers account for about 53% of the package weight.

CONCLUSIONS

There was a considerable variation in package composition and product size, which could provide opportunities to save carbon dioxide emissions in cataract surgery. If all Austrian eye departments were to reduce the material quantities and drape sizes to the lower third of the cataract packages used in the Austria in 2021, cataract package associated CO 2 emissions could be reduced by 34%.

Assessing the astigmatism reducing effect of toric intraocular lenses in eyes with low astigmatism: a randomized masked bilateral comparison

PURPOSE

To evaluate the astigmatism reducing effect of toric intraocular lenses (IOLs) for low amounts of corneal astigmatism.

SETTING

Hanusch hospital, Vienna, Austria.

DESIGN

Randomized, masked, controlled trial with bilateral comparison.

METHODS

Patients scheduled for bilateral cataract surgery and a corneal astigmatism in both eyes between 0.75 and 1.5 D were included in this study. The first eye was randomized to receive either a toric IOL or a non-toric IOL, and the contralateral eye received the other type of IOL. At the follow-up visits, optical biometry, corneal measurements with tomography and topography, autorefraction, subjective refraction, corrected and uncorrected distance visual acuity (CDVA/UDVA) with ETDRS charts and a questionnaire were performed.

RESULTS

Fifty-eight eyes were included in the study. Post-operative median uncorrected distance visual acuity was 0.00 (LogMAR) in the toric eyes and 0.10 in the non-toric eyes (p=0.03). The median corrected distance visual acuity was 0.00 in both groups (p=0.60). Median residual astigmatism determined by subjective refraction and autorefraction in the toric eyes was 0.25 D (diopters) and 0.50 D, respectively, (p=0.04) and 0.50 D and 1.00 D in the non-toric eyes, respectively (p<0.001).

CONCLUSION

The use of a toric IOL appears to be appropriate from a threshold value of approximately 0.75 D pre-operative corneal astigmatism. Further studies in a larger patient population are needed to confirm these results.

Size variability and fitting of 30 gauge thin-wall needles and 3-piece intraocular lens haptics for flanged intrascleral fixation technique

PURPOSE

To assess the diameter of different 30 gauge (G) thin-wall needles and 3-piece intraocular lens (IOL) haptics readily used for the flanged-haptic intrascleral fixation technique.

SETTING

Hanusch Hospital, Vienna, Austria Design: Laboratory Investigation.

METHODS

Five 30G thin-wall needles and five 3-piece IOLs were assessed. An upright light microscopy was used for measurements. The inner and outer diameters of the needles and the end thickness of the haptics were analysed and compared for haptic fitting into the needle.

RESULTS

Among the needles, the inner diameter of the T-lab needle was significantly wider compared to all the others (mean 209.3±8.0μm, p<.001), followed by TSK (194.8±5.0μm), MST (194.7±5.8μm), Sterimedix (187.5±9.0μm) and significantly narrower Meso-relle (mean 178.7±7.0μm, p<.05). The outer diameter of the T-lab needle was significantly larger of all (mean 316.0±2.0 μm, p<.001). Concerning the IOLs, the AvanseePreset Kowa's haptic was significantly thinner (mean 127.2±0.7μm) than all the others, such as the TecnisZA900 Johnson&Johnson (143.5±3.1μm), the CTLucia202 Zeiss (143.8±1.3μm), and the AcrysofMA60AC Alcon (143.9±1.4μm). The only haptic that was thicker than all the others assessed was that of SensarAR40 Johnson&Johnson (170.7±1.7μm, p<.001).

CONCLUSIONS

Most of the analysed haptics would fit into most of the measured needles, with the exception of the Sensar AR40 in combination with the Meso-relle or Sterimedix needles. The combination of a larger needle lumen and a thinner haptic could result in more ease of insertion during surgery. If the dimensions of the needle and IOL haptics used are unknown, we recommend trying insertion before beginning surgery.

ESCRS Clinical Trends Survey 2016-2021: 6-year assessment of practice patterns among society delegates

PURPOSE

To evaluate clinical opinions and practice patterns of delegates to the ESCRS.

SETTING

Clinical Trends Surveys were administered during annual ESCRS congresses held between 2016 and 2021, and data collected online and in-person.

DESIGN

Survey questions addressed several specialty areas, including cataract surgery, presbyopia-correcting and toric intraocular lenses (IOLs), ocular surface disease, and glaucoma.

METHODS

Survey results were compared and analyzed across 6 years. 4 main profile questions were used for cross-tabulation analyses of questions pertaining to refractive surgery-practice location, years in practice, primary surgery setting, and average annual volume of cataract surgery.

RESULTS

The highest number of responses (3019) was collected in 2019, with the lowest (569) received in 2020. The use of presbyopia-correcting and toric IOLs has increased significantly from 2016 to 2021, with certain respondent segments using them more frequently than others. Although optical biometry remains the preferred method for obtaining preoperative measurements, the use of tomography (Scheimpflug) has significantly increased. In 2021, 61.1% and 44.9% of respondents always performed preoperative checks of the ocular surface before refractive and cataract surgery, respectively. The number of respondents who perform glaucoma surgery has significantly decreased over the years, with an increasing number of delegates reporting having only a medical glaucoma practice. On average, 5.4% of patients with cataract and glaucoma underwent combined minimally invasive glaucoma surgery and cataract procedures in 2021.

CONCLUSIONS

Evaluation of the Clinical Trends Survey data provides valuable insights into the shifting practice patterns and clinical opinions of ESCRS delegates.

Remote follow-up after cataract surgery (CORE-RCT): study protocol of a randomized controlled trial

BACKGROUND

Cataract surgery has become one of the most performed surgical procedures worldwide. Postoperative management consists of routine clinical examinations to assess post-operative visual function and detect possible adverse events. Due to the low incidence of complications, the majority of clinic visits after cataract surgery are uneventful. Nonetheless, valuable time and hospital resources are consumed. We hypothesize that remote post-operative follow-up involving teleconsultations and self-assessments of visual function and health status, could be a valid alternative to face-to-face clinical examinations in selected patient groups. The practice of remote follow-up after cataract surgery has not yet been evaluated. The aim of this study is to investigate the validity, safety and cost-effectiveness of remote cataract surgery follow-up, and to report on the patients' experiences with remotely self-assessing visual function.

METHODS

This study is a multicenter, open-label, randomized controlled trial. Patients planned for cataract surgery on both eyes, without ocular comorbidities, are eligible for participation. Participants will be allocated (1:1) into one of the two study groups: 'telemonitoring' or 'usual care'. Participants in the 'telemonitoring' group will perform in-home assessments after cataract surgery (remote web-based eye exams and digital questionnaires on their own devices). Participants in the 'usual care' group will have regular post-operative consultations, according to the study site's regular practice. Outcome measures include accuracy of the web-based eye exam for assessing visual acuity and refraction, patient-reported outcome measures (visual function and quality of life), adverse events, and cost aspects.

DISCUSSION

Investigating remote follow-up after cataract surgery fits the current trends of digitization of health care. We believe that remote self-care can be a promising avenue to comply with the increasing demands of cataract care. This randomized controlled trial provides scientific evidence on this unmet need and delivers the desired insights on (cost)effectiveness of remote follow-up after cataract surgery.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04809402. Date of registration: March 22, 2021.

Influence of Biometric Data on Planning Strabismus Surgery

PURPOSE

To evaluate the influence of optical biometry data (axial eye length, anterior chamber depth) on planning strabismus surgery using a simulation software and partial least squares regression.

METHODS

This retrospective study included patients who had undergone strabismus surgery in one eye involving only the horizontal eye muscles. Furthermore, optical biometry had been performed and the extent of strabismus had been measured pre- and postoperatively. In the next step the strabismus surgery was simulated (See++, RISC, Austria) with and without axial eye length data. In the last step, anatomical data of the eye were used and their influence on the postoperative extent of strabismus was evaluated using partial least squares regression and boot strapping.

RESULTS

Of 97 patients, 92 were included in the analysis. In all cases the extent of strabismus was reduced by at least 25% and in 60% of the cases the reduction was at least 75%. Taking the axial eye length into account improved the simulation slightly (change of surgical planning: 0.30 mm, standard deviation 1.65 mm).

DISCUSSION

The simulation model used showed that including the axial eye length is useful for strabismus surgery planning. However, the anterior chamber depth/axial eye length was found to have a significantly greater impact.

An evaluation of the efficacy of a supplemental computer-based tutorial to enhance the informed consent process for cataract surgery: an exploratory randomized clinical study

Background

To assess whether informing patients with a computer-based tutorial in addition to standard informed consent influences the patient’s attitude towards surgery and increases patient’s knowledge.

Methods

In this prospective, exploratory, randomized clinical study, patients scheduled for their first eye cataract surgery were randomly allocated to two groups, receiving standard face-to-face informed consent (control group) or additionally using an interactive computer-based tool (CatInfo) containing an audiovisual presentation about cataract and its treatment (study group). Cataract-related knowledge and decisional confidence (decisional conflict scale (DCS)) were assessed as well as one-month postoperatively decisional regret (decision regret scale (DRS)) and willingness to exchange face-to-face discussion time for the use of such a tool.

Results

The study comprised 134 patients, 64 patients in the study group and 70 in the control group. Patients in the study group answered more questions correctly, 16.3 ± 2.0 (median 16.5, 11.0–19.0) versus 15.5 ± 1.9 (median 16.0, 8.0–19.0; p = 0.01). Patients showed a high decisional confidence with a study group mean DCS score of 92.4 ± 9.8 (median 96.9, 65.6–100) and control group score of 91.6 ± 10.9 (median 95.3, 43.3–100; p = 0.52). Mean DRS score in the study group was 2.5 ± 8.0 (median 0, 0–40) and 4.3 ± 12.5 (median 0, 0–75) in the control group (p = 0.14). Of study group patients 23 (67.6%) were willing to trade time, on average 158 ± 180 s (median 120 s, 45–900). Satisfaction with the tool was high with a mean of 9.1 ± 1.3 out of 10 (median 9.7, 5.0–10).

Conclusions

Cataract-related knowledge was generally good, with slightly higher scores in the study group. In both groups, decisional confidence was high and regret after surgery was low. A tendency towards slightly higher decisional confidence and lower regret was found in the study group, although these differences were not statistically significant. Additional use of an interactive computer-based tool may prove useful in the informed consent process in a high-volume cataract outpatient setting.

Trial registration

ClinicalTrials.gov, NCT04975126. Retrospectively registered – July 23, 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02652-z.

Attaining optimal flange size with 5-0 and 6-0 polypropylene sutures for scleral fixation

A technique for achieving an optimal flange size with 5-0 polypropylene and 6-0 polypropylene used for flanged intrascleral intraocular lens fixation is described. Flange size in polypropylene sutures is dependent on heating length and independent of forceps grip during heating. It was identified that heating of 1 mm created the optimal flange size for a 5-0 polypropylene suture when used for a 27-gauge needle scleral tunnel and for a 6-0 polypropylene suture when used for a 30-gauge needle scleral tunnel. Alternatively, 2 mm heating of a 6-0 polypropylene suture fits well for a 27-gauge needle tunnel. Even gentle forceps grip caused flattening of the polypropylene sutures but did not influence shaping and sizing of the flange.

The Blue Light Hazard Versus Blue Light Hype

PURPOSE

The blue light hazard is the experimental finding that blue light is highly toxic to the retina (photic retinopathy), in brief abnormally intense exposures, including sungazing or vitreoretinal endoillumination. This term has been misused commercially to suggest, falsely, that ambient environmental light exposure causes phototoxicity to the retina, leading to age-related macular degeneration (AMD). We analyze clinical, epidemiologic, and biophysical data regarding blue-filtering optical chromophores.

DESIGN

Perspective.

METHODS

Analysis and integration of data regarding the blue light hazard and blue-blocking filters in ophthalmology and related disciplines.

RESULTS

Large epidemiologic studies show that blue-blocking intraocular lenses (IOLs) do not decrease AMD risk or progression. Blue-filtering lenses cannot reduce disability glare because image and glare illumination are decreased in the same proportion. Blue light essential for optimal rod and retinal ganglion photoreception is decreased by progressive age-related crystalline lens yellowing, pupillary miosis, and rod and retinal ganglion photoreceptor degeneration. Healthful daily environmental blue light exposure decreases in older adults, especially women. Blue light is important in dim environments where inadequate illumination increases risk of falls and associated morbidities.

CONCLUSIONS

The blue light hazard is misused as a marketing stratagem to alarm people into using spectacles and IOLs that restrict blue light. Blue light loss is permanent for pseudophakes with blue-blocking IOLs. Blue light hazard misrepresentation flourishes despite absence of proof that environmental light exposure or cataract surgery causes AMD or that IOL chromophores provide clinical protection. Blue-filtering chromophores suppress blue light critical for good mental and physical health and for optimal scotopic and mesopic vision.

The human lens: An antioxidant-dependent tissue revealed by the role of caffeine

Cataract is the leading cause of blindness worldwide and surgery is the only option to treat the disease. Although the surgery is considered to be relatively safe, complications may occur in a subset of patients and access to ophthalmic care may be limited. Due to a growing and ageing population, an increase in cataract prevalence is expected and its management will become a socioeconomic challenge. Hence, there is a need for an alternative to cataract surgery. It is well known that oxidative stress is one of the main pathological processes leading to the generation of the disease. Antioxidant supplementation may, therefore, be a strategy to delay or to prevent the progression of cataract. Caffeine is a widely consumed high-potency antioxidant and may be of interest for the prevention of the disease. This review aims to give an overview of the anatomy and function of the lens, its antioxidant and reactive oxygen species (ROS) composition, and the role of oxidative stress in cataractogenesis. Also, the pharmacokinetics and -dynamics of caffeine will be described and the literature will be reviewed to give an overview of its anti-cataract potential and its possible role in the prevention of the disease.

Influence of combined phacovitrectomy without tamponade on intraocular lens displacement and postoperative refraction

PURPOSE

To compare phacoemulsification versus phacovitrectomy regarding postoperative intraocular lens (IOL) shift and refraction.

METHODS

This prospective bilateral comparison study included 40 eyes of 20 patients. Inclusion criteria were combined phacovitrectomy without gas/air tamponade in one eye and cataract surgery in the contralateral eye with implantation of the same IOL. Postoperative anterior chamber depth (ACD) was compared between both groups 1-5 hr, 1 day and 8 weeks after surgery. Postoperative refraction was compared after 8 weeks using the Holladay I, HofferQ, SRK/T, Haigis and Barrett formulae.

RESULTS

There were no intergroup differences in ACD (8 weeks: 0.02 mm absolute difference, SD 0.22, range -0.36 to 0.65, p = 0.401), mean absolute refractive error (8 weeks: Holladay I p = 0.452; HofferQ p = 0.475; SRK/T p = 0.498; Haigis p = 0.869; and Barrett p = 0.352) or percentages within the 0.5 D and 1.0 D range at any time-point. All formulae were optimized for the phacovitrectomy and the cataract groups. There was no correlation of macular thickness change and refractive error (cataract group r²  = -0.13, p = 0.58; phacovitrectomy group r²  = -0.10, p = 0.68).

CONCLUSION

Combined phacovitrectomy without air/ gas tamponade caused neither ACD displacement nor refractive shifts compared to phacoemulsification alone. Surgically induced macular thickness change had no significant influence on postoperative refraction in this study. All five IOL formulae showed comparable postoperative refractive outcomes.

Diagnostic accuracy of code-free deep learning for detection and evaluation of posterior capsule opacification

OBJECTIVE

To train and validate a code-free deep learning system (CFDLS) on classifying high-resolution digital retroillumination images of posterior capsule opacification (PCO) and to discriminate between clinically significant and non-significant PCOs.

METHODS AND ANALYSIS

For this retrospective registry study, three expert observers graded two independent datasets of 279 images three separate times with no PCO to severe PCO, providing binary labels for clinical significance. The CFDLS was trained and internally validated using 179 images of a training dataset and externally validated with 100 images. Model development was through Google Cloud AutoML Vision. Intraobserver and interobserver variabilities were assessed using Fleiss kappa (κ) coefficients and model performance through sensitivity, specificity and area under the curve (AUC).

RESULTS

Intraobserver variability κ values for observers 1, 2 and 3 were 0.90 (95% CI 0.86 to 0.95), 0.94 (95% CI 0.90 to 0.97) and 0.88 (95% CI 0.82 to 0.93). Interobserver agreement was high, ranging from 0.85 (95% CI 0.79 to 0.90) between observers 1 and 2 to 0.90 (95% CI 0.85 to 0.94) for observers 1 and 3. On internal validation, the AUC of the CFDLS was 0.99 (95% CI 0.92 to 1.0); sensitivity was 0.89 at a specificity of 1. On external validation, the AUC was 0.97 (95% CI 0.93 to 0.99); sensitivity was 0.84 and specificity was 0.92.

CONCLUSION

This CFDLS provides highly accurate discrimination between clinically significant and non-significant PCO equivalent to human expert graders. The clinical value as a potential decision support tool in different models of care warrants further research.

Structure-function analysis of MP3 microperimetry versus Octopus perimetry in central glaucomatous visual field defects

INTRODUCTION

To compare the structure-function relationship with microperimetry and Octopus perimetry in primary open angle glaucoma (POAG) patients with central visual field (VF) defects.

METHODS

40 eyes of 24 patients with POAG were enrolled. Circumpapillary retinal nerve fiber layer (cpRNFL) analysis measured by spectral-domain optical coherence tomography (SD-OCT) of the superotemporal, temporal, and inferotemporal optic nerve head (ONH) sectors were related to corresponding microperimetric and Octopus VF clusters using the G2 grid-pattern with dynamic strategy, respectively. The structure-function relationships of both devices were assessed via a segmented regression, as well as linear regression across overall SD-OCT cpRNFL values and outside normative (<1%) SD-OCT cpRNFL values.

RESULTS

Linear and segmented regression fits were similar with both devices. Across overall cpRNFL sectorial values, structure-function relations for the superotemporal, temporal and inferotemporal sectors were R2=0.176 (p=<0.001), R2=0.008 (p=0.069), and R2=0.294 (p=<0.001) for microperimetry, and R2= 0.189 (p=<0.001), R2= 0.020 (p=0.002), and R2= 0.326 (p=<0.001) for Octopus perimetry. For corresponding values outside normative limits (<1%), the relationships were R2=0.113 (p=<0.001), R2=0.001 (p=0.836), and R2=0.420 (p=<0.001) for microperimetry, and R2= 0.192 (p=<0.001), R2= 0.002, (p=0.336), and R2= 0.366 (p=<0.001) for Octopus perimetry.

DISCUSSION/CONCLUSION

Structure-function analysis was similar for both devices. Fundus-tracking should be further evaluated in a longitudinal setting in patients affected by glaucoma.

Thickness of the Protective Layers of Different Ophthalmic Viscosurgical Devices During Lens Surgery in a Porcine Model

Purpose

To evaluate the thickness of the intraoperative layers of 10 different ophthalmic viscosurgical devices (OVD) covering the corneal endothelium during simulated lens surgery in a porcine model.

Methods

This experimental study took place at the Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria. Ten OVDs with different viscoelastic properties (ProVisc, Z-Hyalin plus, Amvisc plus, DisCoVisc, Healon EndoCoat, Viscoat, Z-Hyalcoat, Combivisc, Duo-Visc, and Twinvisc) were assessed in 10 porcine eyes each, yielding a total of 100 eyes. Simulated cataract surgery was performed with volumetric intraoperative OCT imaging during phacoemulsification and during irrigation/aspiration to determine the remaining amount of OVD coating the endothelium over a scan field of 6 × 6 mm. Indirect visualization of the OVD was enabled by replacing the irrigating solution by a higher scattering diluted milk solution. A deep convolutional neural network (CNN) was used to evaluate OVD layer thickness based on the B-scans.

Results

Median thickness values after phacoemulsification were lowest for the cohesive OVDs Z-Hyalin plus (38 µm) and ProVisc (39 µm), followed by the combination systems Twinvisc (342 µm) and Duo-Visc (537 µm). Highest values were observed for the dispersive OVDs and the combination system Combivisc (Viscoat: 957 µm; Z-Hyalcoat: 988 µm, Combivisc: 1042 µm; Amvisc plus: 1259 µm; Healon EndoCoat: 1303 µm; DisCoVisc: 1356 µm). The difference between the OVDs was statistically significant (P < 0.01).

Conclusions

The results of this study confirm that at completion of phacoemulsification, thickest residual layers of OVD remain when using dispersive substances, followed by combination systems and lowest thickness values were observed with cohesive OVDs. The use of an intraoperative OCT and a deep convolutional neural network allowed measurements over a large scan field of 6 × 6 mm and a precise evaluation of the OVD layer coating the corneal endothelium. The OVD layer seemed to be more like a ragged terrain instead of a flat layer, indicating that the film-forming effect of dispersive OVDs is the result of their volume rheology rather than a surface interaction.

Translational Relevance

Evaluating the protective properties provides valuable insights into how different OVDs with different viscoelastic properties form layers beneath the corneal endothelium and helps to understand their persistence during the various steps of cataract surgeries.

Negative dysphotopsia evaluation using individualized eye models

Building on our previously communicated results, the current study evaluates the predictive ability of individualized eye models to localize negative dysphotopsia (ND) in the peripheral field of view (PFoV) In a prospective study conducted at Hanusch Hospital, Vienna, Austria, post-operative biometrical data were acquired from five patients implanted with monofocal IOLs and with ND complaints. A Harms tangent screen subjective method was used to localize in PFoV the perceived shadow (HvF). For computing theoretical retinal irradiance maps, individualized Liou-Brennan (non)-sequential eye models were generated using the acquired biometrical data. Mean axial length was 22.83 (21.05 - 24.80) mm, mean IOL power 24.4 (20.5 - 30.0) D, mean IOL tilt -1.86 (-6.21 - 2.96) degrees and mean decentration 0.16 (-0.27 - 0.44) mm. Average residual astigmatism difference between theoretical and measured data was 0.49 (0.02 - 0.97) D. Aligned with HvF data, the irradiance maps localized ND in the peripheral visual field up to 85 degrees. Previously presented theoretical results evidenced that in identical biometrical conditions, IOLs from different manufacturers with similar mechanical platforms but different optic edge designs are characterized by comparable ND profiles with the peripheral location of the shadows between 69 and 76 degrees. Further expanding the utilization of these eye models, the current results demonstrate their clinical relevance in terms of PFoV localization of ND.

Combining vascular and nerve fiber layer thickness measurements to model glaucomatous focal visual field loss

We compare the focal structure-function correlation of structural measurements of peripapillary retinal nerve fiber layer thickness (RNFL-T) using optical coherence tomography (OCT), capillary density (CD) measurements using OCT-angiography (OCT-A), or a combination of both, with visual field deviation (VFD) in early to advanced glaucoma. Primary open angle glaucoma patients (n = 46, mean ± SD age: 67 ± 10 years; VF mean deviation: -10.41 ± 6.76 dB) were included in this cross-sectional study. We performed 30-2 standard automated perimetry OCT (3.5-mm diameter ring scan) and 15°×15° OCT-A (superficial vascular complex slab). Based on a nerve fiber trajectory model, each VF test spot was assigned to an OCT-A wedge and an OCT ring-sector. Two univariate linear models (M_v and M_t ) using either CD-based vascular (M_v ) or RNFL-T-based thickness information (M_t ) and one multivariate model using both (M_v:t ) were compared in their associations with measured focal VFD, which were higher for the multivariate model M_v:t (mean ± SD correlation coefficient: 0.710 ± 0.086) than for either nested model (0.627 ± 0.078 for M_v and 0.578 ± 0.095 for M_t ). Using a focal visual field approach, the combination of RNFL-T and CD showed better structure-function correlations than thickness or vascular information only.

Precision and refractive predictability of a new nomogram for femtosecond laser-assisted corneal arcuate incisions

PURPOSE

Validating a new nomogram for low to moderate astigmatism (0.75 D to 2.5 D) correction with epithelium- and Bowman-penetrating femtosecond laser-assisted arcuate incisions.

METHODOLOGY

Prospective, interventional case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Cataract patients with low to moderate corneal astigmatism were treated with femtosecond laser-assisted arcuate incisions. Patients with previous refractive corneal treatment were excluded. Outcome assessment was based on manifest refraction, astigmatic vector analysis and visual acuity.

RESULTS

The study analysed 43 eyes of 33 patients after three months and 35 eyes of 27 patients after 12 months. After 12 months, 100% of all eyes treated had ≤1.0 D and 97% ≤0.5 D of subjective residual astigmatism. Mean residual astigmatism was 0.27 D. 90% of all eyes were within one line of difference between UDVA and CDVA. SEQ Mean Absolute Error was 0.26 D and SEQ. Mean error was -0.08 ± 0.32 D. CI was 0.98 ± 0.2 D, and Index of Success, 0.20 ± 0.18 D.

CONCLUSION

The Castrop nomogram showed results that are comparable to or better than results presented in the literature for existing nomograms. Our results for astigmatic reduction are comparable to published results for TIOL implantation. It seems to be a predictable and safe measure to reduce manifest astigmatism.

Physics-aware learning and domain-specific loss design in ophthalmology

The human cataract, a developing opacification of the human eye lens, currently constitutes the world's most frequent cause for blindness. As a result, cataract surgery has become the most frequently performed ophthalmic surgery in the world. By removing the human lens and replacing it with an artificial intraocular lens (IOL), the optical system of the eye is restored. In order to receive a good refractive result, the IOL specifications, especially the refractive power, have to be determined precisely prior to surgery. In the last years, there has been a body of work to perform this prediction by using biometric information extracted from OCT imaging data, recently also by machine learning (ML) methods. Approaches so far consider only biometric information or physical modelling, but provide no effective combination, while often also neglecting IOL geometry. Additionally, ML on small data sets without sufficient domain coverage can be challenging. To solve these issues, we propose OpticNet, a novel optical refraction network based on an unsupervised, domain-specific loss function that explicitly incorporates physical information into the network. By providing a precise and differentiable light propagation eye model, physical gradients following the eye optics are backpropagated into the network. We further propose a new transfer learning procedure, which allows the unsupervised pre-training on the optical model and fine-tuning of the network on small amounts of surgical patient data. We show that our method outperforms the current state of the art on five OCT-image based data sets, provides better domain coverage within its predictions, and achieves better physical consistency.

Anterior chamber depth variability between 2 hydrophobic acrylic 1-piece intraocular lenses: randomized trial

PURPOSE

To analyze the difference in anterior chamber depth (ACD) after uneventful cataract surgery between 2 hydrophobic acrylic 1-piece intraocular lenses (IOLs) with different material properties.

SETTING

Hanusch Hospital, Vienna, Austria.

DESIGN

Single-center, bilateral randomized paired-eye controlled study.

METHODS

Patients scheduled for bilateral cataract surgery were randomized to receive the Clareon IOL in 1 eye and the AcrySof IQ IOL (both Alcon Laboratories, Inc.) in the contralateral eye. Preoperatively, a slitlamp examination, optical biometry (IOLMaster 700, Carl Zeiss Meditec AG), refraction, and visual acuity measurements were performed. ACD was assessed 1 hour and 1 week postoperatively and with additional measurement of uncorrected (UDVA) and corrected distance visual acuity (CDVA) 6 months postoperatively.

RESULTS

80 eyes of 40 patients were analyzed in this study. ACD at the 6-month follow-up was 3.94 ± 0.30 mm for the Clareon IOL and 3.91 ± 0.32 mm for the AcrySof IQ IOL (P = .08). Statistically significant differences in the ACD shift between both IOLs were detected between 1 week and 6 months (P = .04) and 1 hour and 6 months (P = .04). There were no statistically significant differences between both IOLs in UDVA (P = .78), CDVA (P = .59), and spherical equivalent (SE, P = .39) at the 6-month visit. The mean absolute error between the measured and the aimed SE was not significant (P = .97).

CONCLUSIONS

There was no clinically relevant difference in ACD between the Clareon IOL and the AcrySof IQ IOL in patients after uneventful cataract surgery. Both IOLs yielded good refraction and visual acuity outcomes.

Digital ocular swept source optical coherence aberrometry

Ocular aberrometry is an essential technique in vision science and ophthalmology. We demonstrate how a phase-sensitive single mode fiber-based swept source optical coherence tomography (SS-OCT) setup can be employed for quantitative ocular aberrometry with digital adaptive optics (DAO). The system records the volumetric point spread function at the retina in a de-scanning geometry using a guide star pencil beam. Succeeding test-retest repeatability assessment with defocus and astigmatism analysis on a model eye within ± 3 D dynamic range, the feasibility of technique is demonstrated in-vivo at a B-scan rate of >1 kHz in comparison with a commercially available aberrometer.

Repeatability of 2 swept-source OCT biometers and 1 optical low-coherence reflectometry biometer

AIM

To compare the repeatability of 2 swept-source optical coherence tomography (SS-OCT) biometers, IOLMaster 700 (biometer A, Carl Zeiss Meditec AG) and ANTERION (biometer B, Heidelberg Engineering GmbH) and 1 optical low-coherence reflectometry (OLCR) device (biometer C, LENSTAR, LS900; Haag-Streit AG).

SETTING

Department of Ophthalmology, Hanusch Hospital, Vienna Institute for Research in Ocular Surgery-Karl Landsteiner Institute, Vienna, Austria.

DESIGN

Prospective study that included patients scheduled for cataract surgery.

METHOD

Three consecutive measurements were performed with 2 SS-OCT devices and 1 OLCR device. The repeatability of the following biometry variables was compared: keratometry, central corneal thickness, anterior chamber depth (ACD), lens thickness (LT), and axial eye length (AL). To assess the repeatability of each parameter, the within-subject SD (Sw) and coefficient of variation (CoV) were calculated.

RESULT

Fifty eyes of 50 patients were included. The CoV values were below 0.5 for all variables, except for ACD and LT for biometer C. The Sw values for mean keratometry were 0.018 for biometer A, 0.083 for biometer B, and 0.137 for biometer C. For the ACD, the Sw values were 0.039 and 0.004 for biometer A and biometer B, respectively, and 0.134 for biometer C. For the AL, the values were 0.006 for biometer A, 0.008 for biometer B, and 0.012 for biometer C.

CONCLUSIONS

All biometry devices included in the analysis presented a high repeatability. The SS-OCT devices showed a higher repeatability performance compared with the OLCR device.

Lasting Effects: Seven Year Results of the Castrop Nomogram for Femtosecond Laser-Assisted Paired Corneal Arcuate Incisions

PURPOSE

Long-term results of arcuate incisions are rarely reported. This is unfortunate as long-term stability of astigmatic correction is of great interest to surgeons performing astigmatic correction. This study investigates the 7 year stability of results after application of femtosecond laser-assisted arcuate incisions with the Castrop nomogram.

METHODS

Prospective interventional case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Single site, single surgeon study. Seven year results of cataract patients with low to moderate corneal astigmatism receiving femtosecond laser-assisted arcuate incisions using a TechnolasVictus SW 2.7 (Bausch & Lomb Inc, Dornach, Germany) were assessed and compared to 1 year results. Outcome evaluation was based on astigmatic vector analysis, manifest refraction, and visual acuity.

RESULTS

The study analyzed 19 eyes of 19 patients 7 years after surgery. Ocular residual astigmatism changed from -0.26 to -0.39 D. Preoperative corneal astigmatism was -1.51 D. Correction Index changed from 1.0 to 1.16. The magnitude of difference vector changed from 0.26 to 0.39 D. The index of success changed from 0.20 to 0.29. Spherical equivalent remained stable. A slight tendency to change toward astigmatic overcorrection was mainly observed for patients with preoperative with the rule astigmatism, but not with patients with against the rule astigmatism.

CONCLUSIONS

The Castrop nomogram showed stable results 7 years after surgery. Similar to toric IOL surgery, it is advisable to be less aggressive when correcting with the rule astigmatism, to avoid overcorrection over a long period.

Sources of Error in Toric Intraocular Lens Power Calculation

PURPOSE

To evaluate the influencing factors on remaining astigmatism after implanting a toric intraocular lens (IOL) during cataract surgery.

METHODS

This retrospective study included parameters that were considered to have an influence on toric IOL power calculation. Therefore, data from the literature and the authors' own data were used. This included axial eye length, anterior chamber depth, central corneal thickness, corneal radii (anterior and posterior), diurnal changes of the cornea, inter-device differences, rotational misalignment of the IOL, tilt and decentration of the IOL, pupil size, angle kappa, and surgically induced astigmatism. Ray-tracing and Gaussian error propagation analysis was performed to quantify the sources of error.

RESULTS

In total, 4,949 eyes (4,365 eyes of 42 studies and 584 eyes of retrospectively analyzed study data) were included in the study and the difference vector between aimed and calculated remaining astigmatism was 0.81 diopters (D). The main source of error was the preoperative measurement of the cornea (27%), followed by IOL misalignment (14.4%) and IOL tilt (11.3%). Other factors, such as angle kappa (10.9%), pupil size (8.1%), surgically induced astigmatism (7.8%), anterior chamber depth (7.5%), axial eye length (7.5%), and decentration (5.6%), also contributed to the refractive astigmatic error.

CONCLUSIONS

The main source of error in toric IOL power calculation is the preoperative corneal measurement followed by IOL misalignment and tilt. [J Refract Surg. 2020;36(10):646-652.].

Intraocular lens optic edge design for the prevention of posterior capsule opacification after cataract surgery

BACKGROUND

Posterior capsule opacification (PCO) is a clouding of the posterior part of the lens capsule, a skin-like transparent structure, which surrounds the crystalline lens in the human eye. PCO is the most common postoperative complication following modern cataract surgery with implantation of a posterior chamber intraocular lens (IOL). The main symptoms of PCO are a decrease in visual acuity, 'cloudy', blurred vision and reduced contrast sensitivity. PCO is treated with a neodymium:YAG (Nd:YAG) laser to create a small opening in the opaque capsule and regain a clear central visual axis. This capsulotomy might cause further ocular complications, such as raised intraocular pressure or swelling of the central retina (macular oedema). This procedure is also a significant financial burden for health care systems worldwide. In recent decades, there have been advances in the selection of IOL materials and optimisation of IOL designs to help prevent PCO formation after cataract surgery. These include changes to the side structures holding the lens in the centre of the lens capsule bag, called IOL haptics, and IOL optic edge designs.

OBJECTIVES

To compare the effects of different IOL optic edge designs on PCO after cataract surgery.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, Latin American and Caribbean Health Sciences Literature Database (LILACS), the ISRCTN registry, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 17 November 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared different types of IOL optic edge design. Our prespecified primary outcome was the proportion of eyes with Nd:YAG capsulotomy one year after surgery. Secondary outcomes included PCO score, best-corrected distance visual acuity (BCDVA) and quality of life score at one year. Due to availability of important long-term data, we also presented data at longer-term follow-up which is a post hoc change to our protocol.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane and the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included 10 studies (1065 people, 1834 eyes) that compared sharp- and round-edged IOLs. Eight of these studies were within-person studies whereby one eye received a sharp-edged IOL and the fellow eye a round-edged IOL. The IOL materials were acrylic (2 studies), silicone (4 studies), polymethyl methacrylate (PMMA, 3 studies) and different materials (1 study). The studies were conducted in Austria, Germany, India, Japan, Sweden and the UK. Five studies were at high risk of bias in at least one domain. We judged two studies to be at low risk of bias in all domains. There were few cases of Nd:YAG capsulotomy at one year (primary outcome): 1/371 in sharp-edged and 4/371 in round-edged groups. The effect estimate was in favour of sharp-edged IOLs but the confidence intervals were very wide and compatible with higher or lower chance of Nd:YAG capsulotomy in sharp-edged compared with round-edged lenses (Peto odds ratio (OR) 0.30, 95% CI 0.05 to 1.74; I² = 0%; 6 studies, 742 eyes). This corresponds to seven fewer cases of Nd:YAG capsulotomy per 1000 sharp-edged IOLs inserted compared with round-edged IOLs (95% CI 9 fewer to 7 more). We judged this as low-certainty evidence, downgrading for imprecision and risk of bias. A similar reduced risk of Nd:YAG capsulotomy in sharp-edge compared with round-edge IOLs was seen at two, three and five years but as the number of Nd:YAG capsulotomy events increased with longer follow-up this effect was more precisely measured at longer follow-up: two years, risk ratio (RR) 0.35 (0.16 to 0.80); 703 eyes (6 studies); 89 fewer cases per 1000; three years, RR 0.21 (0.11 to 0.41); 538 eyes (6 studies); 170 fewer cases per 1000; five years, RR 0.21 (0.10 to 0.45); 306 eyes (4 studies); 331 fewer cases per 1000. Data at 9 years and 12 years were only available from one study. All studies reported a PCO score. Four studies reported the AQUA (Automated Quantification of After-Cataract) score, four studies reported the EPCO (Evaluation of PCO) score and two studies reported another method of quantifying PCO. It was not possible to pool these data due to the way they were reported, but all studies consistently reported a statistically significant lower average PCO score (of the order of 0.5 to 3 units) with sharp-edged IOLs compared with round-edged IOLs. We judged this to be moderate-certainty evidence downgrading for risk of bias. The logMAR visual acuity score was lower (better) in eyes that received a sharp-edged IOL but the difference was small and likely to be clinically unimportant at one year (mean difference (MD) -0.06 logMAR, 95% CI -0.12 to 0; 2 studies, 153 eyes; low-certainty evidence). Similar effects were seen at longer follow-up periods but non-statistically significant data were less fully reported: two years MD -0.01 logMAR (-0.05 to 0.02); 2 studies, 311 eyes; three years MD -0.09 logMAR (-0.22 to 0.03); 2 studies, 117 eyes; data at five years only available from one study. None of the studies reported quality of life. Very low-certainty evidence on adverse events did not suggest any important differences between the groups.

AUTHORS' CONCLUSIONS

This review provides evidence that sharp-edged IOLs are likely to be associated with less PCO formation than round-edged IOLs, with less Nd:YAG capsulotomy. The effects on visual acuity were less certain. The impact of these lenses on quality of life has not been assessed and there are only very low-certainty comparative data on adverse events.

Effect of Periocular Triamcinolone Acetonide on Prevention of Postsurgical Intraretinal Cystoid Changes after Vitrectomy with Membrane Peeling

BACKGROUND

Newly developed intraretinal cystoid changes after vitrectomy with membrane peeling for removal of epiretinal membranes have the potential to lead to worse postsurgical results compared to patients without. The aim of the present study was to evaluate the feasibility of additional periocular application of triamcinolone acetonide as a routine adjunct at the end of vitrectomy with membrane peeling, and to compare the presence of postsurgical intraretinal cystoid changes in the first 3 months after surgery among patients with idiopathic epiretinal membranes to a historical group of patients that did not receive triamcinolone acetonide.

PATIENTS AND METHODS

The medical records of 41 eyes of 41 patients that underwent 23 G or 25 G pars plana vitrectomy with membrane peeling for removal of epiretinal membranes and additional periocular triamcinolone acetonide application at the end of surgery were retrospectively reviewed. Optical coherence tomography findings during routine follow-ups at 3 - 5 days, 1 month, and 3 months and visual acuity at 3 months after surgery were evaluated and compared to preoperative findings. Furthermore, postsurgical intraocular pressure was assessed.

RESULTS

Periocular triamcinolone acetonide at the end of surgery was well tolerated among all patients. In total, 10% of patients had an increased intraocular pressure at least at one follow-up. Best-corrected visual acuity improved in 91% of patients with idiopathic epiretinal membranes with a mean improvement of + 3 ± 2 lines (Snellen) and was comparable to a historic group of patients (p = 0.307). Early transient macular edema could not be detected in any of the patients, while there were cases with this pathology in the historic group of patients, but neither occurrence of newly developed intraretinal cystoid changes nor macular thickness at 3 months after surgery were significantly different between patients with and without triamcinolone acetonide (p = 0.385 and p = 0.879).

CONCLUSIONS

Periocularly applied triamcinolone acetonide at the end of vitrectomy with membrane peeling was well tolerated and showed prevention of early transient macular edema but did not prevent the development of new postoperative intraretinal cystoid changes.