Assessment of intraocular lens/capsular bag biomechanical interactions following cataract surgery in a human in vitro graded culture capsular bag model.

Intraocular lenses (IOLs) are implanted during cataract surgery. For optimum results, stable positioning of the IOL in the capsular bag is important. Wound-healing events following cataract surgery lead to modification of the capsular bag and secondary visual loss due to posterior capsule opacification. At present, it is unclear how these biological events can affect stability of the IOL within the capsular bag. In the present study, a human in vitro graded culture capsular bag model was the experimental system. Capsulorhexis and lens extraction performed on human donor eyes generated suspended capsular bags (5 match-paired experiments). Preparations were secured by pinning the ciliary body to a silicone ring and maintained in 6 mL of medium for 84 days using a graded culture system: days 1-3, 5% human serum and 10 ng/mL transforming growth factor ß (TGFß2); days 4-7, 2% human serum and 1 ng/mL TGFß2; days 8-14, 1% human serum and 0.1 ng/mL TGFß2; days 15-84, serum-free Eagle's minimum essential medium (EMEM). A CT LUCIA 611PY IOL was implanted in all preparations. Quantitative measures were determined from whole bag images captured weekly. Images were registered using FIJI and analysed in ImageJ to determine capsular bag area; distortion; angle of contact; haptic stability; capsulorhexis area; and a fusion footprint associated with connection between the anterior and posterior capsules. Cell coverage and light scatter were quantified at end-point. The transdifferentiation marker, α-SMA was assessed by immunocytochemistry. Immediately following surgery, distortion of the capsular bag was evident, such that a long axis is generated between haptics relative to the non-haptic regions (short axis). The angle of contact between the haptics and the peripheral bag appeared inversely correlated to capsular bag area. Growth on the peripheral posterior capsule was observed 1 week after surgery and beneath the IOL within 1 month. As coverage of the posterior capsule progressed this was associated with matrix contraction/wrinkles of both the central posterior capsule and peripheral capsular bag. Cells on the central posterior capsule expressed αSMA. Fusion footprints formed in non-haptic regions of the peripheral bag and progressively increased over the culture period. Within and at the edge of the fusion footprint, refractive structures resembling lens fibre cells and Elschnig's pearls were observed. Cell attachment to the IOL was limited. An impression in the posterior capsule associated with the CT LUCIA 611PY optic edge was evident; cell density was much greater peripheral to this indent. Wound-healing events following surgery reduced capsular bag area. This was associated with the long/short axis ratio and angle of contact increasing with time. In summary, we have developed a human capsular bag model that exhibits features of fibrotic and regenerative PCO. The model permits biomechanical information to be obtained that enables better understanding of IOL characteristics in a clinically relevant biological system. Throughout culture the CT LUCIA 611PY appeared stable in its position and capsular bag modifications did not change this. We propose that the CT LUCIA 611PY optic edge shows an enhanced barrier function, which is likely to provide better PCO management in patients.

Case Report: Role of Anterior Segment Optical Coherence Tomography in Late-onset Capsular Block Syndrome.

SIGNIFICANCE: We report the use of anterior segment optical coherence tomography (AS-OCT) as a valuable tool for capsular block syndrome diagnosis and follow-up. PURPOSE: The purposes of this study are to report a case of late-onset capsular block syndrome or lacteocrumenasia and to describe differential diagnosis with other more common phacoemulsification complications such as intraocular lens (IOL) or posterior capsule opacification. CASE REPORT: We report the case of a 56-year-old man with a clinical history of cataract surgery in his left eye. Five years after cataract surgery, he complained of blurred vision and was referred for IOL removal to our hospital. After careful slit-lamp examination, we found that the lens was clear, and opacity belonged to the accumulation of a whitish material in the capsular bag behind the lens. AS-OCT gave the definite diagnosis of capsular block syndrome. Intraocular lens removal had been wrongly indicated, and we treated our patient by YAG laser posterior capsulotomy. AS-OCT confirmed the absence of a further accumulated material, so no other interventions were needed. After treatment, best-corrected visual acuity improved from 0.48 to 0.1 logMAR. CONCLUSIONS: Capsular block syndrome is a rare late-onset complication of cataract surgery causing a deep visual acuity decay. A precise slit-lamp examination and AS-OCT, together, avoid misdiagnosis and unnecessary surgical treatment, which may be needed in case of IOL opacity or fibrotic-like lacteocrumenasia. AS-OCT also helps in determining the treatment outcome. Immediate best-corrected visual acuity improvement is reached after a successful intervention.

Influence of a modified Nd:YAG laser treatment outside the visual axis on the morphology of Elschnig pearls.

PURPOSE: To observe changes in posterior capsule opacification (PCO) after Nd:YAG treatment with and without opening the posterior lens capsule. METHOD: This prospective randomized study included patients with regeneratory PCO. In substudy 1, a small low-energy Nd:YAG capsulotomy was performed (MiniYAG). In substudy 2, a low-energy Nd:YAG laser treatment without opening the lens capsule was performed (GentleYAG). Concerning analysis, in both substudies, the posterior capsule was divided into 4 quadrants and the quadrant where the Nd:YAG laser treatment was performed was randomly allocated. Change in PCO was analyzed using retroillumination images objectively (AQUA score: 0-10). RESULTS: In total, 27 eyes of 25 patients were used for this study. In substudy 1, the mean amount of PCO (AQUA score) for the entire posterior capsule decreased significantly (p < 0.05, ANOVA) from 5.2 (SD: 1.6) before to 4.0 (SD: 1.9) immediately after the MiniYAG. In substudy 2, the mean amount of PCO (AQUA score) for the entire posterior capsule analyzed before and immediately after the GentleYAG was 5.1 (SD: 2.4) and 5.2 (SD: 2.3), respectively. CONCLUSION: Performing a MiniYAG led to a significant PCO reduction. Gentle polishing of the posterior capsule resulted in a relevant reduction of PCO in one third of the patients.

Simple Technique for Transscleral Fixation of a Foldable Posterior Chamber Intraocular Lens Using a Single Suture.

Objective: To explore the simplified technique for transscleral fixation of a foldable posterior chamber intraocular lens (IOLs) in patients with aphakia or inadequate posterior capsule support. Methods: A review was conducted of 18 eyes of eighteen patients with the absence of-or inadequate-capsule support, after the simplified technique of using a foldable posterior chamber intraocular lens (PC IOLs) with stable four-point transscleral fixation, as performed by a skilled surgeon. This technique uses only a single suture and a knot to fix a PC IOL firmly without creating a scleral flap. The mean follow-up time was 18 ± 5.8 months (ranging from 12 to 24 months). Results: All patients exhibited improved visual acuity. No IOL tilt or dislocation or iris capture was observed, and all patients exhibited stable and centered IOL after surgery. No complex complications, such as suture shedding and exposure, corneal endothelial decompensation, persistent uveitis, or retinal detachment and endophthalmitis were observed. Conclusion: The simplified technique proposed here is a reliable, economical, and reproducible method of treating patients with aphakia or inadequate posterior capsule support. It provides excellent IOL stability, reduces surgical duration and complexity, and prevents certain complications.

[Dry transconjunctival sutureless 25-gauge vitrectomy in the treatment of pediatric cataract].

Posterior capsule opacification is the most frequent complication of pediatric cataract surgery. To prevent posterior capsule opacification, primary phacoemulsification, posterior capsulotomy and anterior vitrectomy with intraocular lens implantation is the preferred method in the treatment of pediatric cataract. Anterior vitrectomy cutter, with 18-gauge, maximum frequency at 600/min and has simultaneous cutting, irrigation and aspiration functions, is associated with more complications and poor outcomes. In 20-gauge surgery, pars plana vitrectomy is performed with two-port sclerotomy. The irrigation increases movement of vitreous and 20-gauge sclerotomy needs suture for closing. In 25-gauge surgery, the vitreous cutter can be introduced into the vitreous cavity directly though conjunctiva and sclera. The stab incision is roughly half the size of 20-gauge cutter, therefore, the sclerotomy incision can be left unsutured. Surgery with dry transconjunctival sutureless 25-gauge vitrectomy may decrease the requirement for secondary membrane surgery and the risk for retinal detachment. The application of dry transconjunctival sutureless 25-gauge vitrectomy in the treatment of pediatric cataract is reviewed.

Primary posterior continuous curvilinear capsulorhexis combined with diffractive multifocal intraocular lens implantation.

PurposeTo evaluate the effect of mild posterior capsule opacity (PCO) on visual acuity (VA) in eyes implanted with a diffractive multifocal intraocular lens (IOL) compared with a monofocal IOL, and the effect of posterior continuous curvilinear capsulorhexis (PCCC) combined with diffractive multifocal IOL implantation.MethodsFor the initial evaluation, we compared charge-coupled device (CCD) camera photographs taken through both a monofocal IOL-loaded model eye and a diffractive IOL-loaded model eye under the conditions of both with and without an opaque filter for the simulation of mild PCO. The clinical evaluation involved 20 patients who underwent bilateral implantation of the same diffractive multifocal IOL. In all 20 cases, PCCC was performed in 1 eye (PCCC group) and not performed in the fellow eye (NCCC group). Postoperative clinical results were then compared between the two groups.ResultsThe CCD photographs revealed that the diffractive IOL-loaded eye was more strongly affected by the simulated PCO than was the monofocal IOL-loaded eye. In the clinical setting, the PCCC group registered better results than NCCC group in distance and near VA, low-contrast VA, and contrast sensitivity testing.ConclusionsDiffractive multifocal IOLs tend to be more influenced by mild PCO than do monofocal IOLs, and PCCC prior to IOL implantation can contribute to the avoidance of this effect.

Capsular bag performance of a hydrophobic acrylic 1-piece intraocular lens.

PURPOSE: To compare parameters after 1-piece and 3-piece intraocular lens (IOL) implantation. SETTING: Moorfields West End Clinic, London, United Kingdom, and Hanusch Hospital, Vienna, Austria. DESIGN: Prospective randomized controlled trial. METHODS: Each eye of patients having bilateral surgery for age-related cataract was randomized to have implantation of a 1-piece IOL (Tecnis ZCB00) or a 3-piece IOL (Tecnis ZA9003). Changes in visual acuity, refraction, and anterior chamber depth (ACD) were evaluated during a 2-year follow-up. Intraocular lens tilt and decentration were evaluated using a Purkinje meter. Regeneratory posterior capsule opacification (PCO) was analyzed using retroillumination photographs in Automated Quantification of After-Cataract image-analysis software. RESULTS: This study comprised 100 eyes of 50 patients. No statistically significant differences were found in IOL tilt or decentration between groups (P≥.06). Minimal but statistically significant changes were observed in the vertical tilt component 12 months postoperatively in the 3-piece IOL group (P<.01). The tilt and decentration components did not correlate with changes in sphere or the regeneratory PCO score (r = 0.38, P≥.06). The ACD decreased significantly between 1 day and 1 month postoperatively in both groups (P<.01), with no significant changes afterward (P≥.22). The anterior chamber was significantly deeper in the 1-piece group at all follow-up visits (P<.01). CONCLUSIONS: Both the 1-piece IOL and the 3-piece IOL showed excellent positional stability in the capsular bag, resulting in good clinical outcomes. Regeneratory PCO levels were low and comparable between the IOLs. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Inadvertent trypan blue posterior capsule staining during cataract surgery.

PURPOSE: To report 5 cases of inadvertent posterior capsule staining with trypan blue during phacoemulsification. DESIGN: Retrospective, observational case series. METHODS: Five cases of posterior capsule staining with trypan blue were identified from cataract surgeries performed at an academic institution. All 5 eyes underwent phacoemulsification with use of iris retractors. The surgical videos from each case were reviewed to better understand the mechanisms and risk factors for posterior capsule staining with trypan blue and techniques to avoid this complication. RESULTS: No eyes had clinical evidence of zonular pathology during their preoperative examination. Only 1 patient reported a possible childhood history of trauma to both eyes. One eye had uveitis, requiring posterior synechialysis. All 5 cases involved the use of iris retractors. No other intraoperative complications occurred, and the intraocular lens was successfully placed in the capsular bag in all cases. All eyes had resolution of posterior capsule staining by postoperative day 8. CONCLUSIONS: Inadvertent posterior capsule staining with trypan blue can occur in eyes that appear structurally normal. The use of iris retractors may facilitate posterior capsule staining by allowing the posterior flow of trypan blue under the iris and through the zonules to the posterior capsule. Surgeons should consider techniques to minimize the risk of posterior capsule staining, particularly in cases involving the use of iris retractors.

Refractive changes in nuclear, cortical and posterior subcapsular cataracts. Effect of the type and grade / Cambios refractivos en las cataratas nuclear, cortical y subcapsular posterior. Efecto del tipo y grado

Purpose: To determine the effect of main morphological types and grades of age-related cataracts on refractive error. Methods: We measured 276 subjects with optical compensation prior to the development of cataract. We evaluated 224 eyes with nuclear cataract, 125 with cortical cataract, and 103 with posterior subcapsular (PSC) cataract classified with LOCSIII. We measured visual acuity (VA) with their spectacles and best-corrected visual acuity (BCVA) with chart in decimal scale to obtain the optimal compensation with cataract. We evaluated the differences between compensations. Results: A significant myopic shift was observed in nuclear cataract from low to mild grade (p = 0.031), the same as for PSC cataract from mild to advanced grade (p = 0.025). No significant changes were found for cortical cataract (p = 0.462). Regarding astigmatism, we observed power changes in cortical cataract from low to mild grade (p = 0.03) and axis changes in PSC from low to mild grade (p = 0.02) and in nuclear cataract from mild to advanced grade (p = 0.02). Conclusions: Cataract produces changes in patient’s compensation which depend on severity and type of cataract. For nuclear and PSC cataract, we observed that the higher the grade of severity, the greater the myopic shift. Power astigmatic changes were found in cortical cataract and axis changes in PSC and nuclear cataract (AU)

Objetivo: Determinar el efecto sobre el error refractivo de los principales tipos morfológicos y grados de catarata asociada a la edad. Métodos: Medimos a 276 sujetos con compensación óptica, previamente a la aparición de la catarata. Evaluamos 224 ojos con catarata nuclear, 125 con catarata cortical, y 103 con catarata subcapsular posterior (CSP), clasificados con el sistema LOCSIII. Medimos la agudeza visual (AV) con sus gafas, y la mejor agudeza visual corregida (MAVC) con un test en escala decimal, para obtener la compensación óptima con la catarata. Evaluamos las diferencias entre las compensaciones. Resultados: Se observó un cambio considerable en la catarata nuclear, al pasar del grado bajo al leve (p = 0,031), al igual que en la catarata subcapsular posterior al pasar de grado leve a avanzado (p = 0,025). No se observaron cambios en la catarata cortical (p = 0,462). En cuanto al astigmatismo, observamos cambios de potencia en la catarata cortical al pasar de grado bajo a leve (p = 0,03) y cambios en el eje en la catarata subcapsular posterior al pasar de grado bajo a leve (p = 0,02), y en la catarata nuclear al pasar de grado leve a avanzado (p = 0,02). Conclusiones: La catarata produce cambios en la compensación del paciente, que depende de su severidad y tipo. En la catarata nuclear y subcapsular posterior, observamos que cuanto mayor era el grado de severidad, mayor era el cambio miópico. Se hallaron cambios de potencia astigmática en la catarata cortical, y cambios en el eje en la catarata subcapsular posterior y nuclear (AU)