Intraocular Lens Position Research Articles

Comparative analysis of modulation transfer function in various intraocular lenses under normal, decentration, and tilt conditions

PurposeThis study aims to compare the modulation transfer function (MTF) of different intraocular lenses (IOLs) under normal, decentration, and tilt conditions to evaluate their optical performance. DesignExperimental setting. MethodsA total of 12 IOL models (+20 D diopter, n = 3 each) were measured for MTF using the OptiSpheric IOL system with a 3 mm aperture diameter at a water temperature of 35 °C. Measurements were made with a spatial frequency of 0 - 200 lp/mm at the normal, decentration of 0.5 mm, and tilt of 5° positions. ResultsThe MTF values were significantly different between normal and decentration conditions for XY1A (monofocal, toric) (P = 0.03), Tecnis ZCB00V (P = 0.0009), and NS-60YG (P = 0.004). Differences were significant between normal and tilt conditions for MP70 (P = 0.009), XY1 (P = 0.0005), and Clareon (P = 0.049), and were significant between decentration and tilt conditions only for LentisComfort (bifocal) (P = 0.01). With normal condition, MTF of Eyhance DIB00V (extended depth of focus) showed significant differences with 11 other IOLs (P < 0.0001), while LentisComfort exhibited differences with 10 other IOLs (P < 0.0001) except for XY1A (P = 0.0002). Similarly, with decentration condition, Eyhance DIB00V differed significantly from 11 other IOLs (P < 0.0001). With tilt condition, Eyhance DIB00V showed significant differences with 10 other IOLs (P < 0.0001) except for LentisComfort, which itself differed significantly from 10 other IOLs (P < 0.0001). ConclusionsIn the experimental settings, while specialized IOLs can address specific visual issues, monofocal IOLs remain superior in terms of overall contrast transfer quality and resolution even in the implanted IOL position is not ideal. These results provide a basis for recommending the use of monofocal IOLs in cases where the anterior chamber depth and lens position are prone to instability, such as in eyes with weakened zonules or following glaucoma filtering surgery.

Analysis of the Effective and Actual Lens Position by Different Formulas. Postoperative Application of a Ray-Tracing-Based Simulated Optical Model

(1) Background: This study compares the effective lens position (ELP) and intraocular lens power (IOLP) derived from SRK/T, Hoffer Q, Holladay I, and Haigis formulas with the actual lens position (ALP) and the implanted IOLP after cataract surgery. Additionally, it aims to optimize ALP using a ray-tracing-based simulated optical model to achieve emmetropia. (2) Methods: A retrospective observational study was conducted on 43 eyes implanted with the same monofocal intraocular lens (IOL). Preoperative and postoperative biometric data were collected using the Lenstar LS900. Postoperative measurements included ALP, subjective refraction, and refraction error (RE). Optical simulations (OSLO EDU 6.6.0) were utilized to optimize ALP for emmetropia (ALPIDEAL). (3) Results: Paired t-test results between REOSLO-REOBJ (p-value = 0.660) and REOSLO-RESUB (p-value = 0.789) indicated no significant statistical differences. However, statistically significant differences were found between ALP and ALPIDEAL (p &lt; 0.05), with a difference of −0.04 ± 0.45 mm [ranging from −1.00 to 1.20 mm]. A significant correlation was observed between ΔALP (ΔALP = ALP − ALPIDEAL) and RESUBJ. (4) Conclusions: This customized ray-tracing eye model effectively achieves refractive outcomes similar to those obtained both subjectively and objectively post-surgery. Additionally, it has enabled optical simulations to optimize the IOL position and achieve emmetropia.

Gonioscopy-assisted transluminal trabeculotomy (GATT) with scleral or iris fixation for subluxated intraocular lenses and glaucoma.

This retrospective chart review aims to report a combined surgical approach of intraocular lens (IOL) fixation and gonioscopy-assisted transluminal trabeculotomy (GATT) for the treatment of subluxated IOLs and glaucoma or ocular hypertension. Charts of patients who underwent IOL fixation combined with GATT between November 2019 and July 2023 were reviewed. The main outcome measure was surgical success, defined as a well-centered IOL and an IOP of 18 mmHg or lower and either a 30% IOP reduction or a reduction in medications as compared to baseline. Complications and the need for reoperation were recorded. Eleven patients who underwent GATT with IOL fixation were included. The mean age was 80.45 years (range: 73-90). IOL subluxation was associated with pseudoexfoliation in all cases. Seven patients underwent scleral fixation, and four underwent iris fixation. The mean follow-up was 15.36 (range: 2.7-26.6) months. The success rate was 72.73%. The mean baseline IOP was 20.63 ± 6.56 mmHg on 2.81 ± 1.53 medications. Four patients were on oral carbonic-anhydrase inhibitor (CAI) before surgery. The mean IOP at the end of the follow-up was 13.86 ± 3.5 mmHg on 1.36 ± 1.57 medications, and none were on oral CAIs. No intraoperative complications occurred, and transient hyphema and vitreous hemorrhage were the most common postoperative complications. All patients had a well-centered IOL. No patients needed additional surgery for IOL position or IOP control. The mean corrected distance visual acuity was 0.634 ± 0.62 logMAR at baseline and 0.36 ± 0.38 at the end of follow-up. GATT can be combined with IOL fixation to the sclera or iris to effectively reduce IOP and medication usage.

The uveitis–glaucoma–hyphema syndrome. Part 1. Pathogenesis, clinical features, diagnosis

BACKGROUND: The uveitis–glaucoma–hyphema (UGH) syndrome was first described in 1978 as a complication of anterior chamber polymethyl methacrylate intraocular lenses implantation. Introduction into practice of foldable intraocular lenses with intracapsular fixation has reduced the incidence of UGH. However, this complication still occurs today, especially with extracapsular intraocular lens fixation. AIM: The aim of this study is to describe “uveitis–glaucoma–hyphema” syndrome pathogenesis, clinical features, and diagnosis. MATERIAL AND METHODS: A retrospective analysis of medical data for 2017–2021 identified 100 patients (101 eyes) diagnosed with UGH syndrome, they made up the study group. Complaints, medical history, biomicroscopy, visual acuity and intraocular pressure were assessed. 37 patients underwent anterior segment ultrasound biomicroscopy using the Accutome UBM Plus (USA). RESULTS: The occurrence of UGH syndrome is at least 0.19%. The leading UGH syndrome risk factor was intraocular lens material. In 49% of cases these were AcrySof hydrophobic intraocular lenses. The second UGH risk factor was extracapsular (mixed and sulcus) intraocular lens fixation, occurring, according to ultrasound biomicroscopy, in 54 and 19% of cases, respectively. The most significant diagnostic UGH sign was hyphema (93%). Ocular hypertension was detected in 66%, and uveitis in 57% of cases. CONCLUSIONS: The main UGH syndrome manifestations are hyphema and iris transillumination after phacoemulsification complicated by posterior capsule rupture with extracapsular hydrophobic intraocular lens fixation. The most informative instrumental method to assess intraocular lens position is ultrasound biomicroscopy.

Dynamic Purkinje Meter as a Tool for Intraocular Lens Position Measurement

Due to the increasing demands of today’s society on visual quality and patient comfort, and due to the growing interest in the implantation of new and more complex intraocular lens (IOL) designs, determining the IOL position occupies an important position in current ophthalmological practice. The dynamic Purkinje meter combines the construction of static Purkinje meters, presented in recent years, with dynamic examination of the IOL position according to the optical axis of the IOL.

Prediction of low-addition segmented refractive intraocular lens position and deviation using anterior-segment optical coherence tomography.

This study aimed to develop and analyze the accuracy of predictive formulae for postoperative anterior chamber depth, tilt, and decentration of low-added-segment refractive intraocular lenses. This single-center, retrospective, observational study included the right eyes of 96 patients (mean age: 72.43 ± 6.58 years), who underwent a cataract surgery with implantation of a low-added segmented refractive intraocular lens at the Medical University Hospital between July 2019 and January 2021, and were followed up for more than 1 month postoperatively. The participants were divided into an estimation group to create a prediction formula and a validation group to verify the accuracy of the formula. Anterior segment optical coherence tomography (CASIA 2, Tomey Corporation, Japan) and swept-source optical coherence tomography biometry (IOL Master 700, Carl Zeiss Meditec AG) were used to measure the anterior ocular components. A predictive formula was devised for postoperative anterior chamber depth, intraocular lens tilt, and intraocular lens decentration (p <0.01) in the estimation group. A significant positive correlation was observed between the estimated values calculated using the prediction formula and the measured values for postoperative anterior chamber depth (r = 0.792), amount of intraocular lens tilt (r = 0.610), direction of intraocular lens tilt (r = 0.668), and amount of intraocular lens decentration (r = 0.431) (p < 0.01) in the validation group. In conclusion, our findings reveal that predicting the position of the low-added segmented refractive intraocular lens enables the prognosis of postoperative refractive values with a greater accuracy in determining the intraocular lens adaptation.

Investigation of the myopic outcomes of the newer intraocular lens power calculation formulas in Korean patients with long eyes

This study investigated the underlying causes of the myopic outcomes of the optic-based newer formulas (Barrett Universal II, EVO 2.0, Kane, Hoffer-QST and PEARL-DGS) in long Korean eyes with Alcon TFNT intraocular lens (IOL) implantation. Postoperative data from 3100 randomly selected eyes of 3100 patients were analyzed to compare the reference back-calculated effective lens positions (ELPs) based on the Haigis formula using conventional axial length (AL) and Cooke-modified AL (CMAL) with the predicted ELP of each single- and triple-optimized Haigis formula applied to AL- and CMAL. Contrary to the AL-applied Haigis formula, the predicted ELP curve of the CMAL-applied, single-optimized Haigis formula, simulating the methods of the newer formulas, exhibited a significant upward deviation from the back-calculated ELP in long eyes. The relationship between the AL and anterior chamber depth in our long-eyed population differed from that in the base population of the PEARL-DGS formula. The myopic outcomes in long eyes appeared to stem from the substantial overestimation of the postoperative IOL position with AL modification, leading to the implantation of inappropriately higher-powered IOLs. This discrepancy may be attributed to the ethnic differences in ocular biometrics, particularly the relatively smaller anterior segment in East Asian patients with long AL.

Change in refractive errors with changes in IOL parameters.

This study considered two questions associated with intraocular lens (IOL) power and refraction: (1) Given a refraction with a particular IOL in the eye, what will be the refraction for the IOL or another IOL if located differently with regard to tilt or anterior-posterior position? (2) For a target refraction, what is the power of another IOL if located differently with regard to tilt or position? A thin lens technique was developed to address these questions. For the first question, light was traced through the initial correcting spectacle lens to the cornea, refracted at the cornea, transferred to the position of the initial IOL, refracted at this IOL, transferred to the position of a new IOL (which may be the same IOL but with a different position and/or tilt), refracted backwards through the new IOL, transferred to the cornea and refracted out of the eye to give a new correcting spectacle lens power. For the second question, light was traced through the initial correcting spectacle lens to the cornea, refracted at the cornea, transferred to the position of the initial IOL, refracted at the initial IOL and transferred to the position of a new IOL. Light was also traced through the second correcting spectacle lens, refracted at the cornea and transferred to the position of the second IOL. The difference between the reduced image vergence for the first raytrace and the reduced object vergence for the second raytrace gave the effective power of the second IOL, and from this, the power of the second IOL was determined. Examples are presented for different situations, including a case report.

Visualization of Cataract Surgery Steps With 4D Microscope-Integrated Swept-Source Optical Coherence Tomography in Ex Vivo Porcine Eyes.

To investigate the visualization capabilities of high-speed swept-source optical coherence tomography (SS-OCT) in cataract surgery. Cataract surgery was simulated in wet labs with ex vivo porcine eyes. Each phase of the surgery was visualized with a novel surgical microscope-integrated SS-OCT with a variable imaging speed of over 1 million A-scans per second. It was designed to provide four-dimensional (4D) live-volumetric videos, live B-scans, and volume capture scans. Four-dimensional videos, B-scans, and volume capture scans of corneal incision, ophthalmic viscosurgical device injection, capsulorrhexis, phacoemulsification, intraocular lens (IOL) injection, and position of unfolded IOL in the capsular bag were recorded. The flexibility of the SS-OCT system allowed us to tailor the scanning parameters to meet the specific demands of dynamic surgical steps and static pauses. The entire length of the eye was recorded in a single scan, and unfolding of the IOL was visualized dynamically. The presented novel visualization method for fast ophthalmic surgical microscope-integrated intraoperative OCT imaging in cataract surgery allowed the visualization of all major steps of the procedure by achieving large imaging depths covering the entire eye and high acquisition speeds enabling live volumetric 4D-OCT imaging. This promising technology may become an integral part of routine and advanced robotic-assisted cataract surgery in the future. We demonstrate the visualization capabilities of a cutting edge swept-source OCT system integrated into an ophthalmic surgical microscope during cataract surgery.

Impact of scleral tunnel length on the position of intraocular lenses in flanged intrascleral haptic fixation.

To investigate the effect of scleral tunnel length on the effective lens position and tilt of the intraocular lens (IOL) in flanged intrascleral haptic fixation (ISHF) using anterior segment optical coherence tomography (AS-OCT). Tertiary institution. Retrospective case-control study. This study included 55 and 42 eyes that underwent ISHF with 1.0 and 2.0 mm scleral tunnels, respectively. 23 eyes that underwent sutured fixation were used as a control. The anterior chamber depth (ACD), scleral tunnel length, incident angle of haptic, and tilting of optic were analyzed using AS-OCT. The mean postoperative ACD, vertical tilt angle, and spherical equivalent of the 1.0 mm were 5.27 ± 0.39 mm, 6.04 ± 4.87 degrees, and 0.38 ± 1.03 diopters, respectively. The ACD and vertical tilt angle of the 1.0 mm were larger than those of the others ( P < .001 and P < .05, respectively), and the postoperative spherical equivalent was more hyperopic ( P < .05). The 2.0 mm exhibited a lower frequency of tilting greater than 7 degrees. The intereye difference in ACD between in-the-bag fixation and ISHF of the 1.0 mm tunnel was significantly greater than that in the 2.0 mm tunnel ( P < .05). The 1.0 mm tunnel had a significantly larger incident angle and a longer tunnel length ( P < .001, respectively) and showed a greater difference in the tunnel length on both sides ( P < .05). A shorter tunnel yielded a more unstable IOL position, greater variation in angle and tunnel length, and longer ACD during ISHF. An exact 2.0 mm tunnel must be created on both sides to achieve a stable and predictable IOL position.

Транссклеральная фиксация ИОЛ как оптимальный барьер между камерами глаза при витреальной патологии

In case of regmatogenic retinal detachment, the main point is the formation of a strong barrier between the chambers of the eye using intraocular lenses, including in case of combined pathology, and in particular in the absence of the possibility of implanting a lens into the capsular bag. The distinctive features of the lens location relative to the limb and cornea were identified during a comparative analysis of the position of intraocular lenses in patients with articulation and transcleral fixation using optical coherence tomography. The purpose of the study was to conduct a comparative analysis of the position of intraocular lenses in patients with transcleral fixation and in patients with artificial in the conditions of silicone tamponade of the vitreal cavity. Material and methods. The studies were carried out on 64 eyes of patients aged 56 to 75 years with transcleral fixation and artifaction with silicone tamponade of the vitreal cavity. Results. In patients with transcleral fixation, the distance from the limb to the optical edge of the lens was equal to 4.31 ± 0.82 mm, in the group with articulation 4.11 ± 1.03 mm. The absence of a statistically significant difference indicates the position of the intraocular lens when performing transcleral fixation identical to the location of the lens in the capsule bag. The indicator of the distance from the cornea to the edge of the intraocular lens in patients with transcleral fixation corresponded to 3.72 ± 1.54 mm, in patients with articulation corresponded to 3.21 ± 1.48 mm, while this indicator in the group with transcleral fixation was more variable. Conclusion. In the conditions of silicone tamponade of the vitreal cavity, the technique of transcleral fixation of intraocular lenses provides a single-format position of the lens with artificial patients. Keywords: intraocular lens, transcleral fixation, silicone tamponade

Расчет ИОЛ при комбинированной хирургии: факоэмульсификации катаракты и витрэктомии. Собственный опыт

At the present stage of development of ophthalmic surgical technique, indications for simultaneous cataract phacoemulsification and pars plana vitrectomy are constantly expanding, however, there is a problem of predicting refractive results, which is due to the difficulty of determining the effective position of the intraocular lens (IOL) in the eye without the presence of a vitreous body. Purpose. Assessment of the accuracy of the preoperative calculation of IOL in the eyes during combined surgery — cataract phacoemulsification and vitrectomy on the state of postoperative refraction. Material and methods. Combined surgery of cataract phacoemulsification and vitrectomy of pars plana with a caliber of 25 Gage was performed in 51 people (51 eyes) aged 70.4 ± 8.4 years. The calculation of IOL before surgery was carried out according to the data of a preoperative examination on an optical biometer IOL-Master-700 (Carl Zeiss, Germany), keratopography was performed on a rotary Scheimpflug camera (Oculus, Germany). The data on SRK-T with a range of more than 22.5 mm and Hoffer-Q with a range of less than 22.5 mm were used as a basis. Results. There were no complications during the operations and in the postoperative period. Preoperative uncorrected visual acuity (UCVA) was 0.21 ± 0.2 (0.05 to 0.8) and the best-corrected visual acuity (BCVA) was 0.44 ± 0.22 (from 0.1 to 0.9). The correction is from –9.0 D to +7.75 D (–0.61 ± 2.71 D). 6 months after the operation, the UCVA was 0.67 ± 0.22 (from 0.05 to 1.0), the BCVA was 0.9 ± 0.2 (from 0.3 to 1.0), respectively, while the correction was from –1.25 D to +1.0 D (–0.17 ± 0.94 D). The deviation from the expected refraction of the target at 1 week after surgery was ± 0.5 D, at 6 months after surgery ± 0.4 D, which turned out to be statistically insignificant (p &gt; 0.05). Conclusions. 1. Combined surgery phacoemulsification and vitrectomy in combination of cataracts with pathology of the vitreomacular interface, significantly increases visual acuity after surgery (by 0.43 ± 0.03, p &lt; 0.001). 2. Changes in clinical refraction during implantation of IOL based on hydrophobic acrylic in combined surgery are not statistically significant (an average shift of ± 0,4–0,5 D, p &gt; 0.05), which allows us to apply generally accepted formulas for calculating the effective position of IOL without using correction factors. Keywords: IOL calculation, cataract phacoemulsification, vitrectomy

Repositioned versus exchanged flanged intraocular lens fixation for intraocular lens dislocation

This study aimed to compare the outcomes of flanged intraocular lens (IOL) fixation with new IOL exchange after dislocated IOL removal and repositioned dislocated IOL in patients with IOL dislocation. Eighty-nine eyes that underwent flanged IOL fixation were retrospectively included, with 51 eyes in the exchanged IOL group and 38 eyes in the repositioned IOL group. In both groups, best-corrected visual acuity (BCVA) improved at 1, 3, 6, and 12 months postoperatively and did not differ between the two groups at any of these time points. However, at 1 week postoperatively, BCVA in the repositioned IOL group improved compared with baseline, whereas that in the exchanged IOL group did not. Moreover, there were lesser changes in the corneal endothelial cell density (ECD) and corneal astigmatism in the repositioned IOL group than in the exchanged IOL group. The IOL positions, including IOL tilt and IOL decentration, were not different between the groups. Flanged IOL fixation with new IOL exchange and with repositioned dislocated IOL for patients with IOL dislocation had similar visual outcomes and IOL position. However, the latter had a smaller corneal ECD decrease and astigmatic change. This technique was effective in treating IOL dislocation while minimizing corneal injury.

Anterior Segment Optical Coherence Tomography in Uveitis-Glaucoma-Hyphema Syndrome

ABSTRACT Purpose Uveitis-Glaucoma-Hyphema (UGH) syndrome results from contact between the intraocular lens (IOL) and the iris or ciliary body, leading to uveal structure erosion and blood-aqueous barrier breakdown. Treatment involves various drugs, with IOL removal often being necessary. Diagnosis relies on clinical signs, but imaging techniques like ultrasound biomicroscopy (UBM) or anterior segment optical coherence tomography (AS-OCT) are crucial. AS-OCT accurately depicts IOL position and potential contact, emerging as a primary alternative to UBM in the diagnosis. Our study aimed to correlate AS-OCT findings with clinically detectable iris atrophy in pseudophakic patients with IOL-iris chafing and UGH syndrome. Methods The study retrospectively analyzed patients diagnosed with UGH syndrome presenting at the Ocular Immunology Unit of Reggio Emilia, Italy, from January 2019 to August 2023. Patients’ data were collected. Ophthalmological exams and imaging were performed. The peephole sign in AS-OCT images was evaluated. Statistical analyses were conducted, with a significance level of p ≤ 0.05. Results The study reviewed 22 eyes of 22 patients with UGH syndrome. Four eyes were excluded, leaving 18 patients (8 females, 10 males). Common misdiagnoses included idiopathic anterior uveitis (55.5%) and herpetic anterior uveitis (16.7%). All patients had iris transillumination defects, mostly focal (77.8%). AS-OCT revealed IOL chafing in all the eyes, with peephole sign correlation. More peephole signs occurred with IOL in the sulcus (p-value = 0.08). Conclusion The study recommends AS-OCT for UGH syndrome confirmation and UBM when IOL-iris chafing is not observed on AS-OCT scans.

Pupil versus 1st Purkinje capsulotomy centration with femtosecond laser: Long term outcomes with a sinusoidal trifocal lens.

To assess the role of femtosecond laser-assisted capsulotomy centration in the long-term intraocular positioning of a multifocal intraocular lens. Prospective comparative study. A total of 60 eyes of 30 patients underwent femtosecond laser-assisted Refractive Lens Exchange (RLE). For every patient, capsulotomy centration was randomly performed according to pupil centre (PC) in one eye and first Purkinje reflex (FPR) in the other. The intraocular lens (IOL) positioning, visual acuities, spherical equivalent, internal aberrometry and quality of vision were assessed and compared at 3 years' follow-up between groups (PC and FPR). Intraocular lens positioning showed a statistically significant difference between groups, with a closer centration to the visual axis in the FPR patients (p < 0.001). Internal aberrometry showed higher values in the PC capsulotomy centration group (p < 0.01). FPR centered capsulotomy is associated to a closer centration of the IOL to the visual axis.

MANAGEMENT OF RECURRENT INTRAOCULAR LENS SUBLUXATION AFTER IOL REPOSITION IN APHAKIC PEDIATRIC PATIENT WITH SECONDARY GLAUCOMA AND DEPRIVATIVE AMBLYOPIA

Introduction : Malposition of the intraocular lens (IOL) can be in the form of decentration, subluxation, dislocation, or luxation. Conservative management and surgery are used to treat IOL subluxation.&#x0D; Case Illustration : A 14-year-old boy came to clinic with chief complaint of diplopia since 1 month ago. There were histories of cataract surgery of both eyes in 2014 and 2015 at a secondary hospital, secondary IOL implantation and membranectomy of right eye in December 2017, and IOL reposition of right eye in February 2022. Ophthalmologist examination revealed BCVA of right eye is 0.5 with S+10.00 C-2.25 x180 and left eye is 1/300. The right eye's intraocular pressure was 23 mmHg and the left eye's was 16 mmHg. Anterior segment examination of the right eye showed aphakia with subluxation of the IOL to the inferotemporal (Figure 1) and PC IOL of the left eye. Patient diagnosed with aphakia ODS with IOL subluxation OD, secondary glaucoma OD, astigmatisma Hypermetropia composite OD, astigmatism Myopia Compositus OS, Hypermetropia OD, Myopia Gravior OS, Deprivative Amblyopia ODS, and Last Eye OD. Patient given monofocal spectacles, prednisolone asetat eye drop tapering dose, and timolol maleate eye drop, with observation of IOL position&#x0D; Discussion : Recurrent IOL subluxation without clear signs of zonular or capsular instability in this patient was managed with conservative management using spectacles and medication due to secondary glaucoma. Long-term observation needed to evaluate possibility of repositioning or explanting the IOL in the future.&#x0D; Conclusion : Management of IOL subluxation could temporarily undergo conservative treatment. A surgical approach is considered in cases of recurrent dislocation

Incidence and predisposing factors of intraocular Lens tilt following secondary ciliary sulcus implantation in children: An ultrasound biomicroscopic study.

To evaluate the incidence and causes of intraocular lens (IOL) tilt and changes in anterior chamber angle after secondary IOL sulcus implantation following congenital cataract removal. A retrospective observational study was conducted on children who underwent secondary sulcus IOL implantation following pediatric cataract removal in the period from 2017-2020 in Cairo university Hospitals. Children were examined for IOL position, centration, and tilt. Intraocular pressure (IOP) measurement, fundus and gonioscopic examination was performed. Ultrasound biomicroscopy (UBM) was performed on both eyes in children with clinically detected tilt. Ciliary sulcus secondary IOL implantation was performed in 102 eyes (57 children). IOL tilt was detected clinically in 16 eyes of 14 children (15.7%). UBM showed clinically undetected tilt in the fellow eye in additional 4 eyes. The mean angle of tilt was 12.8 ± 3.9° in clinically detected tilt compared to 7.5 ± 1.2° in UBM detected tilt. Mean anterior chamber depth (ACD) was 2.4 ± 0.5 mm IOP was >21 mmHg in 1.9% of eyes. Narrowing of the anterior chamber angle (ACA) after sulcus implantation occurred in 40% of eyes with open angle. Sulcus proliferations and obliterated sulcus were detected in all 20 eyes. Sommering's ring was found in 7 eyes (35%). Axial length, corneal diameter, and presence of persistent fetal vasculature did not affect IOL position. The presence of residual lens matter or an obliterated ciliary sulcus is associated with a higher incidence of IOL malposition following ciliary sulcus implantation.

CONTRIBUTION FACTORS OF EFFECTIVE LENS POSITION, TILT, AND DECENTRATION DURING FLANGED SCLERAL FIXATION OF INTRAOCULAR LENS: A Model Eye Study.

The authors aimed to elucidate the factors related to effective lens position, tilt, and decentration of scleral fixed intraocular lenses (IOLs) with a flanged haptic technique in an artificial eye model using anterior segment optical coherence tomography. Two bent 27-gauge needles were passed through a 1.0- or 2.0-mm scleral tunnel, 2.0 mm posterior to the limbus and 180° apart. Both haptics of a three-piece IOL were docked with guide needles and externalized. Factors related to the IOL position were analyzed using anterior segment optical coherence tomography and a stereomicroscope. The 1.0-mm scleral tunnel induced a significantly longer effective lens position than the 2.0-mm tunnel and suture fixation ( P < 0.05 and P < 0.01, respectively). Discrepancy in scleral tunnel length induced higher decentration of the optic to the opposite side of the haptic-embedded shorter tunnel and tilt perpendicular to the fixed axis than that in the scleral tunnel of the same length ( P < 0.001 and P < 0.05, respectively). If the scleral fixation points of both haptics are not exactly 180° apart, the IOL may become decentered and tilted ( P < 0.01 and P < 0.05, respectively). In the flanged haptic technique, the length, balance, and position of both scleral tunnels determine IOL effective lens position, tilt, and decentration.

Research progress on prediction of postoperative intraocular lens position.

With the progress in refractive cataract surgery, more intraocular lens (IOL) power formulas have been introduced with the aim of reducing the postoperative refractive error. The postoperative IOL position is critical to IOL power calculations. Therefore, the improvements in postoperative IOL position prediction will enable better selection of IOL power and postoperative refraction. In the past, the postoperative IOL position was mainly predicted by preoperative anterior segment parameters such as preoperative axial length (AL), anterior chamber depth (ACD), and corneal curvature. In recent years, some novel methods including the intraoperative ACD, crystalline lens geometry, and artificial intelligence (AI) of prediction of postoperative IOL position have been reported. This article attempts to give a review about the research progress on prediction of the postoperative IOL position.

Anatomical and optical origins of negative dysphotopsia

Negative dysphotopsia (ND) is a complaint after, an otherwise uneventful, cataract surgery with intraocular lens (IOL) implantation. It is generally described as a shadow in the temporal peripheral visual field. Approximately 3% of the patients suffer from this condition and complaints range from mild visual field defects to a significant loss of peripheral vision that disturbs daily life. Originally, this condition was poorly understood as conventional ophthalmic techniques are not designed for a comprehensive evaluation of the peripheral vision. In the last years, however, a combination of dedicated anatomical measurements and optical ray tracing simulations have revealed the cause of ND and proposed different treatments.In this presentation the basic principles of ray tracing of the eye will be presented, followed by the main results of the ESCRS vRESPOND study. In this study, a detailed anatomical assessment of the pseudophakic population with and without ND was made. The distinct differences between both groups, such as a smaller (p = &lt;0.01) and more decentered (p &lt; 0.01) pupil and an increased temporal‐tilted iris (p &lt; 0.01), will be discussed. Interestingly, high‐resolution ocular MRI revealed that the in‐the‐bag IOL position and retinal shape did not differ significantly between both groups. The impact of these differences on the patient's peripheral vision will be shown through ray tracing simulations. First the optical origin of the shadow, caused by light rays missing the IOL, will be presented, followed by a quantitative analysis of the effect the different anatomical and IOL‐design parameters on the severity of this shadow. At the end of the presentation, the optical rationale behind some of the treatments of ND will be discussed.