scholarly journals Time Course of Lens Epithelial Cell Behavior in Rabbit Eyes following Lens Extraction and Implantation of Intraocular Lens

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Daijiro Kurosaka ◽  
Toshiyasu Imaizumi ◽  
Junya Kizawa
Keyword(s):  
Intraocular Lens ◽  
Time Course ◽  
Smooth Muscle Actin ◽  
Posterior Capsule ◽  
Posterior Chamber ◽  
Lens Fiber ◽  
Lens Extraction ◽  
Fiber Cells ◽  
Soemmering Ring

Background. After cataract surgery, some lens epithelial cells (LECs) transdifferentiate into myofibroblast-like cells, which causes fibric posterior capsule opacification (PCO). Residual LECs differentiate into lens fiber cells, forming Elschnig pearls with PCO. This study was carried out to identify the time course of both types of LEC behavior in rabbit eyes following lens extraction and implantation of an intraocular lens (IOL). Methods. Phacoemulsification and implantation of posterior chamber IOLs were performed in rabbit eyes. Following enucleation, immunohistochemical methods were used to detect α-smooth muscle actin (α-SMA), a marker for myofibroblast-like cells, in the pseudophakic rabbit eyes. A mouse monoclonal antibody against α-SMA was used. Results. Soon after the operation, the LECs migrated and covered the lens capsule. Thereafter, the LECs around the anterior capsular margin were always positive for α-SMA. However, the distributions of these cells were not consistent. In some specimens, α-SMA-positive LECs were present around the IOL optic early after surgery, but most of them had disappeared several weeks after the surgery. The residual cells induced fibrotic PCO. In the other specimens, most LECs around the IOL optic except the anterior capsular margin were negative for α-SMA. In the peripheral region covered by the peripheral anterior and posterior capsules, LECs on the posterior capsule always differentiated into lens fiber cells and formed a Soemmering ring. Thereafter, migration of lens fiber cells from the Soemmering ring and differentiation of LECs in situ on the central posterior capsule consisted of Elschnig pearls type of PCO. Conclusions. Although postoperative LEC behavior is not consistent, residual α-SMA-positive LECs induced fibrotic PCO. The lens fiber cells that migrated from the peripheral capsular bag or that were differentiated in situ covered the central posterior capsule, forming Elschnig pearls with PCO.

Contrasting patterns of c-myc and N-myc expression in proliferating, quiescent, and differentiating cells of the embryonic chicken lens

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 813-820
Author(s):  
L.L. Harris ◽  
J.C. Talian ◽  
P.S. Zelenka
Keyword(s):  
Cell Proliferation ◽  
Protein Product ◽  
Mrna Levels ◽  
Lens Fiber ◽  
Proliferating Cells ◽  
Fiber Cells ◽  
Embryonic Chicken ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation

The present study uses the polymerase chain reaction and in situ hybridization to examine c-myc and N-myc mRNA in the embryonic chicken lens at 6, 10, 14 and 19 days of development and compares the pattern of expression obtained with the developmental pattern of cell proliferation and differentiation. In the central epithelium, c-myc mRNA levels were proportional to the percentage of proliferating cells throughout development. N-myc mRNA expression in this region was relatively low and showed no correlation with cell proliferation. The ratio of N-myc to c-myc mRNA increased markedly with the onset of epithelial cell elongation and terminal fiber cell differentiation, although both c-myc and N-myc mRNAs continued to be expressed in postmitotic, elongating cells of the equatorial epithelium and in terminally differentiating lens fiber cells. Thus, increased expression of N-myc, a gene whose protein product may compete with c-myc protein for dimerization partners, accompanies the dissociation of c-myc expression and cell proliferation during terminal differentiation of lens fiber cells.

Update on Paediatric Refractive Surgery

2015 ◽  
Vol 09 (02) ◽  
pp. 104
Author(s):  
Amir Pirouzian ◽  
◽  
◽  
◽  
Hesam Hashemian ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Refractive Surgery ◽  
Case Reports ◽  
Age Groups ◽  
Cross Linking ◽  
Posterior Chamber ◽  
Original Research ◽  
Phakic Intraocular Lens ◽  
Lens Extraction ◽  
Accommodative Esotropia

Purpose:To provide a summary of the most recent evidence-based data on the paediatric refractive surgery.Methods:A review of the published studies from 1990 to 2015 was undertaken with emphasis on recent articles from 2010 to 2015.Results:Searching Scopus and PubMed, using the keywords of refractive surgery, phakic, paediatric, IOL, children and amblyopia alone or in various combinations yielded a total of about 48 articles on this topic from 1990 to 2015. Excluding review articles, fewer than 35 articles were included. Original research articles were only in the form of case reports/series on corneal laser surgery and phakic intraocular lens implantation or clear lens extraction. A total of fewer than 800 patients and 700 eyes had undergone a form of refractive surgery listed above. No randomised clinical trial (RCT) study was available on the topic. Age varied from 7 months to 17 years for non-corneal cross-linking studies. Most commonly performed operations were corneal laser ablative procedures (photorefractive keratectomy [PRK], laser-assisted sub-epithelial keratectomy [LASEK], laser-assistedin situkeratomileusis [LASIK]), phakic intraocular lens implantations (p-IOL, anterior or posterior chamber) and clear lens extraction. The indications for surgical intervention were for refractive – high amplitude iso-ametropic or anisometropic – amblyopia in the setting of the previously failed medical interventions and spectacle intolerance or non-compliance (physical or neurobehavioral in nature) and high accommodative esotropia with/without amblyopia. The main objective of the studies was to assess for visual acuity gained or lost following surgery and for correction of strabismus, i.e. achieving orthophoria. Further search on the keywords ‘cross-linking, cornea, rings and children’ from the same databases resulted in 130 articles. No RCT study was available on the topic. Age varied from 7 months to 17 years for non-corneal cross-linking studies. The focus of the most recent refractive surgery articles has been on the treatment and stabilisation of irregular myopic astigmatism from kerato-ectatic conditions by means of corneal cross-linking and intrastromal ring/in-lay implantation.Discussion:Refractive surgery remains a controversial topic in paediatric age population. However, the evidence clearly supports refractive surgery for treatment of children with refractive amblyopia and for treatment of accommodative esotropia in children unable or unwilling to wear spectacles or contact lenses.Conclusion:Consensus exists among published authors that refractive surgery may be considered in children with refractive amblyopia after exhausting various therapeutic medical options for amblyopia. Published authors have universally endorsed undertaking prospective multi-centred RCTs to conclusively establish the long-term safety and efficacy of various types of refractive surgery in the paediatric patients of different age groups.

scholarly journals A Comparison of Clinical Outcomes of Dislocated Intraocular Lens Fixation between In Situ Refixation and Conventional Exchange Technique Combined with Vitrectomy

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Sun Jung Eum ◽  
Myung Jun Kim ◽  
Hong Kyun Kim
Keyword(s):  
Intraocular Lens ◽  
Case Series ◽  
Posterior Chamber ◽  
Retrospective Case ◽  
Exchange Group ◽  
Additional Surgery ◽  
Posterior Chamber Intraocular Lens ◽  
Induced Astigmatism ◽  
Iol Exchange

Purpose. To evaluate surgical efficacy of in situ refixation technique for dislocated posterior chamber intraocular lens (PCIOL).Methods. This was a single-center retrospective case series. 34 patients (34 eyes) who underwent sclera fixation for dislocated IOLs combined with vitrectomy were studied. Of 34 eyes, 17 eyes underwent IOL exchange and the other 17 eyes underwent in situ refixation.Results. Mean follow-up period was 6 months. Mean logMAR best corrected visual acuity (BCVA) was not significantly different between the groups 6 months after surgery (0.10±0.03in the IOL exchange group and0.10±0.05in the refixation group;p=0.065). Surgically induced astigmatism (SIA) was significantly lower in the refixation group (0.79±0.41) than in the IOL exchange group (1.29±0.46) (p=0.004) at 3 months, which persisted to 6 months (1.13±0.18in the IOL exchange group and0.74±0.11in the refixation group;p=0.006). Postoperative complications occurred in 3 eyes in the IOL exchange group (17.6%) and 2 eyes in the refixation group (11.8%). However, all of the patients were well managed without additional surgery.Conclusion. The in situ refixation technique should be preferentially considered if surgery is indicated since it seemed to produce a sustained less SIA compared to IOL exchange.

scholarly journals Pars plana vitrectomy in management of giant retinal tear and retinal detachment following iris-fixated anterior chamber phakic intraocular lens implantation

2018 ◽  
Vol 11 (1) ◽  
pp. e228052
Author(s):  
Sagnik Sen ◽  
Raghav Dinesh Ravani ◽  
Prateek Kakkar ◽  
Atul Kumar
Keyword(s):  
Retinal Detachment ◽  
Anterior Chamber ◽  
Intraocular Lens ◽  
Posterior Vitreous Detachment ◽  
Posterior Chamber ◽  
Phakic Intraocular Lens ◽  
Retinal Tear ◽  
Giant Retinal Tear ◽  
Pars Plana

This case report describes a 26-year-old man presenting with a giant retinal tear (GRT) with retinal detachment (RD) following implantation of iris-fixated anterior chamber phakic intraocular lens (AC-PIOL) for high myopia and occurrence of intraoperative aberrations during vitrectomy due to the presence of AC-PIOL in situ. Posterior chamber PIOL have been well reported to be associated with GRT with RD. Very few reports exist of GRT with RD following AC-PIOL. Moreover, the presence of iris-fixated AC-PIOL, in this case, led to the formation of ghost images intraoperatively especially during crucial steps like induction of posterior vitreous detachment which has never been reported.

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