Comparison of the effects of viscoelastic agents on clinical properties of the Unfolder lens injection system

Intraoperative Intraocular Lens Waste: Incidence, Cost and Reasons

PURPOSE

To evaluate the incidence and cost of intraocular lens(IOL) waste during IOL implantation, as well as the reasons for it.

METHODS

A retrospective analysis was conducted on the data of 485 patients from the IOL waste registers of a single tertiary eye hospital in China during 2016-2020. The primary outcomes were the incidence, cost, and reasons for different IOL properties. Cases were examined to ascertain IOL material, design, procedural details, and causes of waste.

RESULTS

IOL waste occurred in 485 (6.62‰) of the 73,246 IOL implantations during the study period. The total cost of IOL waste was 429, 850.26 Chinese Yuan (CNY) related to waste with an average cost of 2, 442.33 CNY per procedure during the study period. Comparisons between IOL properties showed that polymethyl methacrylate (PMMA) material (39, 2.05%), three-piece design (142, 1.49%), and secondary IOL implantation (26, 2.16%) were associated with IOL wastage, and the difference was statistically significant. The causes of IOL waste were damage (107, 60.80%), patient reasons (37, 21.26%), aseptic errors (22, 12.50%), IOL quality problems (8, 4.55%), and loss (2, 1.14%).

CONCLUSIONS

The incidence of IOL waste is low, but still leads to a significant cost burden due to a large number of cataract surgeries. PMMA material, three-piece design, and secondary implantation were identified as factors increasing IOL waste. Damage emerged as the primary reason for waste, largely attributed to human error. Therefore, the development of strategies to mitigate IOL waste is imperative.

Evaluation of Nozzle Tip Damage in Intraocular Lens Injectors with V-Shaped Notch

INTRODUCTION

Damage to the nozzle tips of intraocular lens (IOL) injectors has been associated with various adverse events and even IOL surface abnormalities after IOL implantation. In this study, nozzle tip damage of three different injector models with v-notched nozzle tips was systematically evaluated using our self-developed system - the Heidelberg Score for IOL injector damage.

METHODS

Nozzle tip damage was categorized into 6 grades: no damage (grade 0), slight scratches (1), deep scratches (2), extensions (3), cracks (4), and bursts (5). Each grade was assigned to a score of 0-5. In each IOL injector group, all IOLs were divided into 2 subgroups based on IOL power: +15 to +21D group and +21 to +26D group. The total scores for each group were the sum of scores for all injectors in this group. Further analysis was performed on the nozzle tip configuration and parameters in each injector model.

RESULTS

The median (Q1-Q3) for each injector group in group +15 to +21D was 1.5 (1-2) for Avansee, 4 (3-4) for iSert, and 4 (3-4) for multiSert. A statistically significant difference was found between Avansee and iSert (p < 0.001) as well as between Avansee and multiSert (p < 0.01) in terms of median scores. The median (Q1-Q3) for each injector group in group +21 to +26D was 1.5 (1-2) for Avansee, 4 (4-4) for iSert, and 3 (3-3.75) for multiSert. A statistically significant difference was found between Avansee and iSert in terms of median scores (p < 0.001). The outer cross-sectional diameters were 1.80 and 1.78 mm for Avansee, 1.70 and 1.69 mm for iSert, and 1.69 and 1.68 mm for multiSert. The radii of each notch-based circle were 0.21 mm (Avansee), 0.09 (iSert), and 0.06 (multiSert), respectively. The tip angles for three injector models were 48° (Avansee), 46° (iSert), and 37° (multiSert).

CONCLUSIONS

Avansee showed the least nozzle tip damage of all three groups. Compared with our earlier study using preloaded injectors with intact endpieces, all the injector groups with v-notched nozzle tips had more damage to the nozzle tip. It was found that the closer the notch of the nozzle tip was to the letter "V," the more damaged the nozzle tip was after IOL implantation.

Rotational stability of plate-haptic toric intraocular lenses in Asian eyes: risk period for intraocular lens rotation and its influencing factors

PURPOSE

To investigate the rotational stability of plate-haptic toric intraocular lenses (IOLs) during 3-month follow-up.

SETTING

Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN

Prospective observational study.

METHODS

Patients with cataracts implanted with AT TORBI 709M toric IOLs were enrolled and followed at 1 hour, 1 day, 3 days, 1 week, 2 weeks, 1 month, and 3 months postoperatively. A linear mixed model of repeated measures was applied to investigate the time course of absolute IOL rotation change. The 2-week overall IOL rotation was analyzed in the age, sex, axial length (AL), lens thickness (LT), preexisting astigmatism, and white-to-white subgroups.

RESULTS

A total of 328 eyes of 258 patients were included. The rotation from the end of surgery to 1 hour and 1 day to 3 days was significantly smaller compared with the rotation from 1 hour to 1 day but more than that at other time intervals in the overall group. 2 weeks postoperatively, the mean uncorrected distance visual acuity and remaining positive cylinder were 0.19 ± 0.22 logMAR and 0.60 ± 0.44 diopters, respectively. Significant between-group differences in 2-week overall rotation were found in the age, AL, and LT subgroups.

CONCLUSIONS

Maximum rotation occurred within 1 hour to 1 day postoperatively, and the first 3 days postoperatively was a high-risk period for the plate-haptic toric IOL rotation. Surgeons should make the patients aware of this.

Propensity-matched comparison of postoperative stability and visual outcomes of toric intraocular lens with or without a capsular tension ring and updated meta-analysis

PURPOSE

To assess the contribution of capsular tension ring (CTR) to postoperative stability and visual outcomes of a plate-haptic toric intraocular lens (IOL).

METHODS

This prospective cohort study was performed among patients underwent toric IOL (AT TORBI 709 M) implantation with or without CTR at the Eye and ENT hospital between April 2020 and November 2021. Propensity score matching (PSM) was performed to balance baseline factors. Postoperatively, uncorrected distance visual acuity (UCVA) and residual astigmatism, as well as IOLs' rotation, tilt, and decentration, were analyzed. Grouped multiple linear regression analysis was used to model predictive factors of rotation in each group. Additionally, a meta-analysis of data from 4 publications (284 eyes) and current study was performed to evaluate the effect of CTR co-implantation on toric IOL rotation.

RESULTS

After PSM, 126 eyes from each group were included for further analysis. Postoperatively, UDVA was 0.31 ± 0.38 logMAR and 0.27 ± 0.36 logMAR in the CTR and NCTR groups, respectively (P = 0.441), and residual astigmatism was 0.75 ± 0.52 D and 0.86 ± 0.65 D, respectively (P = 0.139). The rotation of toric IOL was significantly smaller in the CTR group than in the NCTR group (4.63 ± 6.27 vs. 10.93 ± 16.05 degrees, P < 0.001). The regression models of the two groups and the coefficients of LT were significantly different (P < 0.001 and P = 0.001, respectively). Furthermore, the meta-analysis confirmed that CTR co-implantation reduced toric IOL rotation (MD, - 1.59; 95% CI, - 3.10 to - 0.09; P = 0.038).

CONCLUSION

CTR enhances rotational stability of toric IOL by reducing the impact of LT, and CTR co-implantation is recommended in patients with lens thickness (LT) ≥ 4.5 mm, white-to-white (WTW) ≥ 11.6 mm, or high preexisting astigmatism.

A laboratory evaluation of nozzle tip damage in four generations of intraocular lens injector systems using a self-developed damage scale

During intraocular lens (IOL) implantation it is not uncommon for the injector’s nozzle-tip to get damaged. However, the damage has not been systematically described or evaluated using an objective scale. In this study we developed our own system—the Heidelberg Score for IOL Injector Damage (“HeiScore”), which was used to grade 60 injectors from four generations of injector models (Monarch III D, AcrySert C, UltraSert, AutonoMe) made by the same manufacturer. (Alcon Laboratories Inc.) HeiScore has six grades of nozzle-tip damage: no damage (which was graded 0); slight scratches (1), deep scratches (2), extensions (3), cracks (4) and bursts (graded number 5). The score for each injector model was the sum of all grades (total number), and we could compare the four injector models. The injectors showed varying damage profiles, from “no damage” to “crack”. A tendency of a lower damage score in the newer generations of IOL injectors was noted. However, a statistically significant difference was observed only between Monarch III D and AutonoMe. The “Heidelberg Score for IOL Injector Damage” could efficiently and effectively evaluate the damage to IOL injector systems, which might help manufacturers optimize the positioning of the IOL in the injector during pre-loading.

Rotational stability of Toric intraocular lenses

BACKGROUND

A prospective study to evaluate the rotational stability of toric intraocular lenses (IOLs).

METHODS

A prospective study of 30 eyes in 29 patients. All patients with regular astigmatism of range 0.75-4 D were included in the study. Exclusion criteria included irregular corneal astigmatism, post-refractive surgery and corneal dystrophies. All patients underwent uncomplicated phacoemulsification cataract surgery by the same surgeon. Three eyes with corneal astigmatism of 0.75-1.5 D were implanted with the AcrySof SA60T3 IOL, eight eyes with astigmatism between 1.5 and 2.0 D received the SA60T4 IOL and eight eyes with astigmatism between 2.0 and 2.50 D received the SA60T5 and rest with astigmatism of 2.5 D and higher received SA60T6 and above models. Main outcome measure was the post-operative position of the lens, assessed at day 1, 1 week, 1 month and 6 months, using toric marker and the slit lamp.

RESULTS

There was no significant rotation of IOL observed during a follow-up period of 6 months. Overall, the post-operative rotation was within 5° in 95% of cases. There was no trend for either clockwise or anti-clockwise rotation. However, IOL rotation happens mostly within the first month of surgery, and if it is significant, it requires early repositioning.

CONCLUSION

Toric IOLs are very effective and consistent in correcting astigmatism during the cataract surgery. Once placed to its position, toric IOLs demonstrate rotational stability in the capsular bag.

Visual outcome and refractive status with monofocal toric intraocular lens implantation to correct astigmatism during cataract surgery

Purpose:

Measurement, calculations, visual assessment, and refractive status after monofocal toric intraocular lens (IOL) implantation were the purpose of this study.

Methods:

This was a hospital-based interventional prospective study, where 40 eyes were included with astigmatism of more than 2D. They underwent biometric assessment using Lenstar. Toric IOL power calculation was done based on Barrett's Toric calculation method. Preoperative axis marking was done using both bubble marker and direct slit beam to avoid cyclotorsion in sleeping position. On table, axis marking was reassessed. Post phacoemulsification, monofocal Supra Phob Toric IOL was rotated till its marking matches corneal axis marking. Postoperative best-corrected visual acuity was measured at 1 and 3 months.

Results:

Mean of refractive astigmatism reduced from 3.55 ± 0.97 preoperatively to 0.81 ± 0.28 at 1 month and 0.79 ± 0.27 at 3 months postoperatively. In total, 92.5% had residual astigmatism less than 1D at 3 months postoperatively, while 7.5% eyes had residual astigmatism more than 1D. In total, 72.5% patients had IOL rotation of less than or equal to 5°, 20% patients had it between 6° and 10° and 7.5% eyes had more than 10° at day 7 postoperatively, which required IOL repositioning.

Conclusion:

Accurate measurement of parameters and proper calculation reduce the postoperative residual astigmatism after toric IOL.

Hydroxypropyl methylcellulose: Physicochemical properties and ocular drug delivery formulations

Hydroxypropyl methylcellulose (HPMC) is a cellulose ether widely used in drug formulations due to its biocompatibility, uncharged nature, solubility in water and thermoplastic behavior. Particularly for ocular and ophthalmic formulations, HPMC is applied as viscosity enhancer agent in eye drops, gelling agent in injections, and polymeric matrix in films, filaments and inserts. The different therapeutic approaches are necessary due to the complex anatomic structure of the eye. The natural ocular barriers and the low drug permeation into the circulatory system make the drug administration challenging. This review presents the eye anatomy and the usual local routes of drugs administration, which are facilitated by the physicochemical properties of HPMC. The relationship between chemical structure and physicochemical properties of HPMC is displayed. The different types of formulations (local application) including HPMC for ocular drug delivery are discussed with basis on recent literature reports and patents.

Comparative evaluation of rotational stability and visual outcome of toric intraocular lenses with and without a capsular tension ring

Purpose:

To evaluate the rotational stability of toric intraocular lens (IOL) when co-implanted with a capsular tension ring (CTR) as compared to that of a toric IOL without a CTR.

Methods:

This was a prospective randomized clinical trial performed in a tertiary care centre in India. Fifty adult human eyes with visually significant cataract and regular corneal astigmatism ≥1.5D divided into two groups of 25 eyes each, A and B by simple randomization. Eyes with corneal pathology, lens subluxation, and a specular endothelial cell count <2000/mm² were excluded from the study. The eyes in both the groups underwent standard phacoemulsification and were implanted with a toric IOL. In Group A, a CTR was put in the bag before IOL implantation. The groups were called for follow-up on day 1, 1 week, 1 month, and 3 months, postoperatively. The axis of the toric IOL on each visit was measured by slit lamp imaging in retroillumination and analyzed digitally.

Results:

Mean rotation of toric IOL at 3 months postoperatively was 1.85 ± 1.72° in Group A and 4.02 ± 2.04° in Group B. The difference was statistically significant (P = 0.003).

Conclusion:

Coimplantation of a CTR is a safe and effective technique for ensuring better rotational stability of toric IOLs.

Toric Intraocular Lens for Astigmatism Correction in Cataract Patients

Background:

To assess the clinical consequences of AcrySof toric intraocular lens (IOL) and Hoya toric IOL implantation to correct preexisting corneal astigmatism in patients undergoing cataract surgery.

Materials and Methods:

In this study, we examined 55 eyes of 45 patients with at least 1.00 D corneal astigmatism who were scheduled for cataract surgery. After phacoemulsification, toric IOL was inserted and axis was aligned. We observed the patients, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, manifest refraction, and IOL axis alignment 6 months after surgery.

Results:

After 6 months, the UDVA was 0.17 ± 0.17 logMAR in the AcrySof group and 0.17 ± 0.18 logMar in the Hoya group. More than 78% of eyes in the AcrySof group and 80% of eyes in the Hoya toric IOL achieved a UDVA of 20/40 or better. In the AcrySof group, the mean preoperative corneal astigmatism was 2.73 ± 0.92 D. The mean postoperative refractive astigmatism was 0.84 ± 0.63 D. In the Hoya group, the preoperative corneal astigmatism was 2.58 ± 0.76 D and the postoperative refractive astigmatism was 0.87 ± 0.66 D (P < 0.05). The mean AcrySof IOL axis rotation was 1.88° ± 3.05°. In the Hoya group, the mean axis rotation was 1.53° ± 3.66°. All changes in visual and refractive data before and after surgery were statistically significant (P < 0.05). There was no significant difference between the two groups regarding refractive and visual outcome after surgery (P > 0.05 for all).

Conclusion:

Implantation of AcrySof toric IOL and Hoya toric IOL was an effective way to correct preexisting corneal astigmatism in cataract surgery.

Vector analysis of astigmatism correction after toric intraocular lens implantation

PURPOSE

To determine astigmatic changes by vector analysis and postoperative refractive and visual outcomes after implantation of the monofocal aspheric bitoric AT Torbi 709M toric intraocular lens (IOL).

SETTING

Three centers in Salzburg, Austria, and Alicante and San Sebastián, Spain.

DESIGN

Prospective interventional case series.

METHODS

Preoperative and postoperative visual acuity, subjective and objective refractions, and corneal radii using a topographer were examined in all patients. All patients had postoperative examinations within the first week and at 6 to 12 weeks. Astigmatic changes were evaluated using the Alpins vector method based on 3 fundamental vectors as follows: target induced astigmatism (TIA), surgically induced astigmatism (SIA), and difference vector. The various relationships between these 3 vectors were calculated, providing an extensive description of the astigmatic correction achieved.

RESULTS

Eighty-eight eyes (71 patients) were included. Postoperatively, refractive cylinder was reduced significantly (P < .001), concurrent with visual improvement. The mean magnitude of the SIA vector (2.54 diopters [D] ± 1.21 [SD]) was slightly higher than the mean magnitude of the TIA vector (2.37 ± 1.15 D) at the last follow-up. The mean difference vector was 0.46 ± 0.46 D, the mean magnitude of error was 0.16 ± 0.46 D, and the mean correction index was 1.09 ± 0.21, all indicating minimal overcorrection at 3 months that remained stable during the follow-up.

CONCLUSION

Implantation of the toric IOL was safe and effective for the treatment of eyes with cataract in combination with preexisting regular corneal astigmatism over a short-term follow-up.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Intraocular lens delivery characteristics of the preloaded AcrySof IQ SN60WS/AcrySert injectable lens system

OBJECTIVE

To evaluate the delivery characteristics of the AcrySof IQ SN60WS intraocular lens (IOL) injected via a preloaded AcrySert delivery system.

DESIGN

Prospective observational case series.

METHODS

setting: This study was carried out in the cataract service of an ophthalmic hospital that serves a large sector of inner-city London. patient population: The study included all patients undergoing routine phacoemulsification procedures with implantation of the SN60WS IOL via the preloaded system over 5 consecutive months. A total of 85 patients (85 eyes) were included in this study. intervention: Phacoemulsification procedures conducted by 7 surgeons were digitally captured. outcome measures: Video recordings of the IOL delivery stage were analyzed by a single observer. Of particular interests were the orientation of the leading haptic and optic on insertion, the degree of intrawound manipulation of the injector, and the time required to satisfactorily deliver the IOL into the capsular bag in a correct orientation. Problems of IOL delivery were also noted.

RESULTS

In 38 out of 85 eyes (45%), correct IOL delivery behavior was achieved with the leading haptic orientating to the left of the surgeon and thus did not require any intrawound rotational manipulation of the injector. Forty-seven of the 85 eyes (55%) required additional rotational manipulation of IOL orientation. Other problems recorded were trapped trailing haptic, haptic-optic adhesion, overriding of the plunger over the optic, and trauma to optic edge. The average time to achieve satisfactory IOL position was 47 seconds. IOL power and the grade of the operating surgeon did not appear to influence the event of a misdirected leading haptic.

CONCLUSIONS

The AcrySof SN60WS/AcrySert system does not appear to meet the expectations of pro-viding a predictable means of IOL delivery.

The course of surface deposits on a hydrophilic acrylic intraocular lens after implantation through a hexagonal cartridge

AIM

To evaluate the outcome of surface deposits that occurred during implantation of hydrophylic acrylic intraocular lenses (IOLs) through a hexagonal cartridge.

METHODS

Surface deposits were observed on the posterior surface of the ACR6D SE IOLs that were injected through a hexagonal cartridge filled with sodium hyaluronate 1%. All the patients were examined 1 day, 1 week, 1 month, 6 months and 1 year postoperatively. The location of the deposits was recorded and photographed. The patients were questioned about blurred vision, glare or halos.

RESULTS

Linear or curly deposits were detected on the posterior surface of the IOL in six patients. In four patients, the deposits were peripheral and were observed 1 week postoperatively. In two patients, the deposits were noticed immediately after implantation. In one eye, they were misinterpreted as a crack in the IOL's optic and were left in the eye. In the second patient the deposits were removed immediately after implantation with forceps. The deposits that were left after implantation (five eyes) did not resolve during 1 year of follow-up. None of the eyes developed abnormal inflammatory reaction. In three eyes the best-corrected visual acuity (BCVA) was 6/6. In the other three eyes the BCVA was 6/12. None of the patients experienced any visual disturbance.

CONCLUSIONS

Implantation of the ACR6D SE IOL through a hexagonal cartridge can lead to the formation of deposits on the posterior surface of the lens. The deposits do not resolve and may resemble a crack in the IOL. The deposits left on the IOL had no clinical relevance in our patients.

Folding procedure for acrylic intraocular lenses

PURPOSE

To compare in vitro the effect of 2 standard methods of folding acrylic intraocular lenses (IOLs) on surface characteristics and bacterial adhesion.

SETTING

Eye Clinic and Department of Health-Microbiology Unit, University of Florence, Florence, Italy.

METHODS

To evaluate the effect of folding, 2 types of acrylic IOLs were not folded or folded with a forceps or an injector and then processed for scanning electron microscopy (SEM) examination. Bacterial adhesion was assessed using an ocular isolate of Pseudomonas aeruginosa. Nonfolded and folded IOLs were placed in test tubes containing the bacterial suspension for direct counting of viable adherent bacteria and for SEM.

RESULTS

The injector-folded IOLs did not show major alterations on the surface; 5 of the 9 forceps-folded IOLs showed marks or scratches in the profile of the optic. The mean number of viable adherent bacteria per area of IOL optic was 1082 (95% confidence interval [CI], 835-1330) in forceps-folded IOLs, 366 (95% CI, 192-359) in injector-folded IOLs, and 206 (95% CI, 123-289) in nonfolded IOLs. Scanning electron microscopy confirmed more surface irregularities on forceps-folded IOLs, with bacteria adherent preferentially on the surface scratches.

CONCLUSION

Forceps-folding provoked more surface irregularities, which probably make IOLs more susceptible to bacterial adhesion.

Surface abnormalities on hydrophilic acrylic intraocular lenses implanted by an injector

PURPOSE

To describe and evaluate abnormalities on the surface of hydrophilic acrylic intraocular lenses (IOLs) that were implanted using an injector.

SETTING

Department of Ophthalmology, University of Graz, Graz, Austria.

METHODS

This study comprised 70 eyes having phacoemulsification and implantation of an EasAcryl (n = 50) or Inject-A (n = 20) IOL. Both hydrophilic IOLs are biconvex and have a high water content (26%), plate-haptic design, and no angulation. The IOLs were folded in a cartridge under hydroxypropyl methylcellulose and implanted by an injector.

RESULTS

Thirteen EasAcryl and 5 Inject-A IOLs had multiple white lines in the direction of the longitudinal axis on the posterior surface immediately after implantation. On 1 EasAcryl IOL, the white lines were separated by a clear central zone and were on the anterior surface. Another EasAcryl IOL had a 1.0 mm crack.

CONCLUSIONS

The abnormalities on the posterior surface of high-water-content hydrophilic acrylic IOLs disappeared or were almost gone within 1 month postoperatively and do not appear to be a concern for surgeons. These abnormalities are likely the result of the IOLs' hydrophilicity and high water content and friction in the injector barrel.