Insight into small eyes: a practical description from phenotypes presentations to the management.

This narrative review aimed to have an algorithmic approach to microphthalmos by a systematic search. The definition can be related to a number of special phenotypes. In the more challenging cases of complex microphthalmos, relative anterior microphthalmos, and nanophthalmos, the surgeon can approach these cases more safely if they have a deep understanding of the anatomical variations and ideal formulae for intraocular lens computation and knows how to avoid intra- and post-operative complications. In this article, we review the criteria by which we recognize and describe pre-, intra-, and post-operative considerations, as well as discuss the ideal intraocular lenses for microphthalmos, given the intricate varieties of small eye phenotypes.

DMEK surgical training: An instructional guide on various wet-lab methods.

Descemet membrane endothelial keratoplasty (DMEK) is a partial-thickness corneal transplantation procedure that involves selective transplantation of the Descemet membrane and endothelium. DMEK offers significant advantages over other keratoplasty techniques, such as faster visual rehabilitation, better final visual acuity due to minimal optical interface effects, lower risk of allograft rejection, and less long-term dependence on topical steroids. Despite all its advantages, DMEK has been found to be more challenging than other corneal transplantation techniques, and its steep learning curve appears to be an obstacle to its widespread use and adoption by corneal surgeons worldwide. DMEK surgical training laboratories (wet labs) provide a window of opportunity for surgeons to learn, prepare, manipulate, and deliver these grafts in a risk-free environment. Wet labs are a significant learning tool, especially for those institutions that have limited tissue availability in their local centers. We provide a step-by-step guide for preparing DMEK grafts using different techniques on human and nonhuman models with instructional videos. This article should eventually help the trainees and the educators understand the requirements for performing DMEK and conducting a DMEK wet lab and develop their skills and interests from a wide variety of available techniques.

Clear corneal incision, an important step in modern cataract surgery: a review.

A clear corneal incision (CCI) is the most commonly used entrance site in modern phacoemulsification cataract surgery. Despite some initial concerns about increased endophthalmitis rates through a self-sealing CCI, recent literature suggests that the risk of infection with proper wound construction and all other necessary precautions is minimal. The technique of creating a clear corneal incision has, with recent developments in corneal imaging, undergone critical appraisal leading to a better understanding of incision architecture. Many surgeons operate through smaller incisions, and they have a wide choice of surgical instruments to create their corneal incisions. The aim of this review is to discuss the history and the current status of clear corneal incision creation, the design and materials of surgical blades, and the current trends in manufacturing and sustainability. Although disposable instruments have some advantages and are very popular, recycling, if possible, and avoiding unnecessary plastic waste are important considerations. In any case, the step of CCI is a small one for the surgeon, but a big one for the eye. That is why it has to be done with the utmost precision and in-depth knowledge is important.

Intraocular bag-in-the-lens exchange: indications, outcomes, and complications.

PURPOSE: To report the indications, outcomes, and complications regarding bag-in-the-lens (BIL) intraocular lens (IOL) exchange over a period of 13 years in a tertiary ophthalmologic center. SETTING: Department of Ophthalmology of the University Hospital of Antwerp, Belgium. DESIGN: Observational retrospective study. METHODS: Between 2003 and 2020, 12 176 patients were operated using the BIL technique. Adult patients who underwent an intraocular BIL exchange were included, and the demographics, indications, outcomes, and complications were recorded. RESULTS: 59 eyes (0.48%) of 59 patients who underwent a BIL exchange between 2007 and 2020 were included. The mean age was 61.15 ± 13.53 years. The mean time between primary surgery and IOL exchange was 25.73 ± 41.88 months. The main indication for explantation was refractive surprise mostly related to patient risk factors, for example, preoperative corneal and refractive surgery. The mean preoperative uncorrected (UDVA) and corrected (CDVA) distance visual acuity were 0.36 ± 0.24 and 0.79 ± 0.24, respectively. The postoperative 1-month UDVA and CDVA were 0.66 ± 0.28 and 0.86 ± 0.19, respectively. The improvement in UDVA was statistically significant (<0.0001). The most common intraoperative complication was damage to the anterior hyaloid in 9 eyes (15%), which did not prohibit reimplantation of a secondary BIL. CONCLUSIONS: BIL to BIL exchange was a viable and successful technique that provides good refractive results with few, manageable complications. Because of the tertiary profile of the study center with referral of complex cases, BIL was the preferred IOL in patients at risk for postoperative refractive surprise.

Phacoemulsification After Descemet Membrane Endothelial Keratoplasty: Incidence and Influence on Endothelial Cell Density.

PURPOSE: To analyze the incidence of cataract extraction after Descemet membrane endothelial keratoplasty (DMEK) in phakic eyes and to evaluate the effect of phacoemulsification after DMEK on the donor endothelial cell density (ECD). METHODS: The clinical data of phakic patients with DMEK were examined. From this cohort, all patients who subsequently underwent phacoemulsification after DMEK were reviewed. Data from a prospectively collected dataset were analyzed, including demographic profile, ECD, corrected distance visual acuity (CDVA), central corneal thickness (CCT), and complications. RESULTS: From a series of 261 phakic patients with DMEK, 35 eyes (13.4%) required cataract surgery within the mean follow-up period of 54.2 ± 28 months. The mean time from DMEK to phacoemulsification was 18 ± 13 months (range: 3 to 69 months). The probability of cataract extraction after DMEK was 0.06 (95% CI: 0.03 to 0.09) at 1 year and 0.17 (95% CI: 0.12 to 0.22) at 10 years, respectively. ECD decreased from 1,314 ± 524 cells/mm2 before phacoemulsification to 1,167 ± 443 cells/mm2 (-11%) at 1 to 6 months postoperatively (P = .333). CDVA improved from 0.27 ± 0.13 logMAR preoperatively to 0.07 ± 0.12 logMAR at 1 to 6 months postoperatively. CCT before phacoemulsification was 532 ± 46 µm and remained stable at 539 ± 56 µm at 1 to 6 months after phacoemulsification. Phacoemulsification did not elicit DMEK graft detachment in any of the eyes studied. CONCLUSIONS: The incidence and 10-year projection of cataract extraction in phakic eyes with DMEK was relatively low. Phacoemulsification after DMEK provided excellent CDVA outcomes, did not induce graft detachment, and was associated with an acceptable decrease in ECD. [J Refract Surg. 2021;37(2):119-125.].

Fifteen years of IOL exchange: indications, outcomes, and complications.

PURPOSE: To report the indications, frequency, and outcomes regarding intraocular lens (IOL) exchange in 2 university hospital tertiary referral settings over a period of 15 years. SETTING: Ophthalmology departments of the University Hospital Antwerp and the University Hospital Leuven, Belgium. DESIGN: Retrospective cross-sectional study. METHODS: In this retrospective study, included were patients who underwent an IOL exchange between 2002 and 2017. Patient demographics, surgical indication, comorbidities, visual outcomes, and complications were reported. Patients who underwent IOL repositioning or add-on IOL implantation or extraction, and patients who were left aphakic, were excluded. RESULTS: Included in the study were 492 eyes. The mean age was 66.0 ± 13.3 years (range 19-91 years). The mean time between primary surgery and IOL exchange was 54.61 ± 67.07 months (range 0-343 months). Primary indication for explantation was IOL opacification, and the most common ophthalmic comorbidity was a previous history of vitreoretinal surgery. Preoperatively, the mean uncorrected visual acuity (UCVA) and corrected distance visual acuity (CDVA) were 0.47 ± 0.27 (range 0-1) and 0.61 ± 0.32 (range 0-1.2), respectively. Postoperative UCVA and CDVA was 0.7 ± 0.3 (range 0-1.2) and 0.8 ± 0.28 (range 0.05-1.6), respectively. The increase in both CDVA and UCVA was statistically significant (P < .001, paired t test). The most common complication perioperatively was vitreous prolapse, which occurred in 61 eyes (16%). CONCLUSIONS: IOL exchange is a challenging yet valuable treatment option for a wide spectrum of problematic IOL outcomes. The most common indication remains IOL opacification, although IOL dislocation and patient dissatisfaction are increasing as indications.

In Vitro Evaluation and Transplantation of Human Corneal Endothelial Cells Cultured on Biocompatible Carriers.

Corneal transplantation is currently the only effective treatment option for dysfunctional corneal endothelial cells (CEC). In this study, we test in vitro the surgical potential of cultivated human corneal endothelial cells (hCEC) on human anterior lens capsule (HALC), LinkCell™ bioengineered collagen sheets of 20-µm thickness (LK20), and denuded Descemet membrane (dDM) as tissue-engineered grafts for Descemet membrane (DM) endothelial keratoplasty (DMEK) to bypass the problem of donor tissue availability. Primary hCEC cultured on all carriers formed a monolayer of tightly packed cells with a high cell viability rate (96% ± 4%). hCEC on HALC and LK20 showed unremarkable expression of zonula occludens-1 (ZO-1) and Na+/K+-adenosine triphosphatase (ATPase), while Na+/K+-ATPase expression of cells seeded on dDM was mainly cytoplasmic. All hCEC-carrier constructs were evaluated by simulating DMEK surgery in vitro using a human donor cornea without DM mounted on an artificial anterior chamber (AC) and a regular DMEK-graft used as a surgical reference model. During in vitro surgery, hCEC-HALC constructs behaved most similarly to a DMEK-graft during implantation and unfolding, showing good adhesion to the bare stroma. On the other hand, hCEC-LK20 and hCEC-dDM constructs required some additional handling because of challenges related to the surgical procedure, although they were both successfully unfolded and implanted in the artificial AC. The hCEC-dDM constructs showed similar graft adherence as hCEC-HALC constructs, while adherence of hCEC-LK20 constructs was less effective. After the in vitro surgery, the estimated area populated by viable cells on the hCEC-HALC and hCEC-LK20 constructs was ∼83% and ∼67%, respectively. Overall, hCEC-HALC constructs behaved most similarly to a DMEK-graft during in vitro DMEK surgery, while graft adhesion and surgical handling, respectively, are parameters still requiring optimization for hCEC-LK20 and hCEC-dDM constructs.

Corneal regeneration: A review of stromal replacements.

Corneal blindness is traditionally treated by transplantation of a donor cornea, or in severe cases by implantation of an artificial cornea or keratoprosthesis. Due to severe donor shortages and the risks of complications that come with artificial corneas, tissue engineering in ophthalmology has become more focused on regenerative strategies using biocompatible materials either with or without cells. The stroma makes up the bulk of the corneal thickness and mainly consists of a tightly interwoven network of collagen type I, making it notoriously difficult to recreate in a laboratory setting. Despite the challenges that come with corneal stromal tissue engineering, there has recently been enormous progress in this field. A large number of research groups are working towards developing the ideal biomimetic, cytocompatible and transplantable stromal replacement. Here we provide an overview of the approaches directed towards tissue engineering the corneal stroma, from classical collagen gels, films and sponges to less traditional components such as silk, fish scales, gelatin and polymers. The perfect stromal replacement has yet to be identified and future research should be directed at combined approaches, in order to not only host native stromal cells but also restore functionality. STATEMENT OF SIGNIFICANCE: In the field of tissue engineering and regenerative medicine in ophthalmology the focus has shifted towards a common goal: to restore the corneal stroma and thereby provide a new treatment option for patients who are currently blind due to corneal opacification. Currently the waiting lists for corneal transplantation include more than 10 million patients, due to severe donor shortages. Alternatives to the transplantation of a donor cornea include the use of artificial cornea, but these are by no means biomimetic and therefore do not provide good outcomes. In recent years a lot of work has gone into the development of tissue engineered scaffolds and other biomaterials suitable to replace the native stromal tissue. Looking at all the different approaches separately is a daunting task and up until now there was no review article in which every approach is discussed. This review does include all approaches, from classical tissue engineering with collagen to the use of various alternative biomaterials and even fish scales. Therefore, this review can serve as a reference work for those starting in the field and but also to stimulate collaborative efforts in the future.

A review of the evidence for in vivo corneal endothelial regeneration.

Human corneal endothelium has long been thought to be a nonmitotic cell layer with no endogenous reparative potential. Pathologies that damage endothelial function result in corneal decompensation and, if untreated, blindness. The mainstay of treatment involves partial or complete corneal replacement, amounting to 40% of all corneal transplants performed worldwide. We summarize the case reports describing complications postoperatively in the form of (sub)total graft detachment and those resulting in postoperative bare stroma. Complications during cataract and glaucoma surgeries leading to an uncovered posterior cornea are also included. We discuss the newer treatment strategies that are alternatives for current Descemet membrane endothelial keratoplasty and Descemet stripping automated endothelial keratoplasty, including partial grafts and stripping of the diseased cell layer. In more than half of the cases reviewed, corneal transparency returned despite incomplete or no corneal endothelial cell transplantation. We question the existing paradigm concerning corneal endothelial wound healing in vivo. The data support further clinical study to determine the safety of simple descemethorexis in central endothelial pathologies, such as Fuchs endothelial corneal dystrophy, where presence of healthy peripheral cells may allow successful corneal recompensation without the need for donor cells.

Scleral Lenses Reduce the Need for Corneal Transplants in Severe Keratoconus.

PURPOSE: To investigate the success and failure rates of scleral lens correction in severe keratoconus. DESIGN: Retrospective case series. METHODS: Study population comprised patients with keratoconus who attended the keratoconus clinic at the Antwerp University Hospital, Belgium, between January 1, 2010, and December 31, 2014. The included eyes had maximal keratometry values ≥ 70 diopters, as measured using the sagittal curvature map that was obtained by Scheimpflug tomography. The exclusion criteria included amblyopia, mental retardation, and concomitant ocular disease that limited their visual potential. RESULTS: Scleral lens fitting was proposed for the 75 eyes included in the study. Eight eyes underwent transplant surgery because of insufficient visual acuity with the lenses, lens intolerance, and issues with handling the lenses. Twelve eyes did not have lenses fitted because of good visual acuity in the other eye or a contraindication for lens wear. Three eyes were successfully fitted with corneal or hybrid lens wear. Scleral lenses were prescribed in 51 of 75 eyes. The mean gain in visual acuity (lens vs spectacle-corrected visual acuity) was 0.54 ± 0.18 (decimal fraction, Snellen eye chart). Seven eyes were lost to follow-up, 4 eyes abandoned wearing the scleral lens because of an inability to handle the lenses, and 40 eyes wore the lenses at their last follow-up visit, with a mean follow-up interval of 30.15 ± 12.83 months. CONCLUSIONS: Forty of the 51 eyes with severe keratoconus that would otherwise have undergone transplant surgery were successfully treated with long-term scleral lens wear. In this way, the indication for keratoplasty was more than halved in our keratoconus population.

Repeatability and inter-device agreement for three different methods of keratometry: Placido, Scheimpflug, and color LED corneal topography.

PURPOSE: To determine the repeatability of a color LED corneal topographer (Cassini; iOptics, The Hague, The Netherlands) and compare it with Placido and Scheimpflug based devices (EyeSys 2000; EyeSys Laboratories, Houston, TX, and Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany). METHODS: This prospective study involved 20 healthy volunteers (20 eyes) recruited from the staff of the Antwerp University Hospital. For each eye, three measurements were taken using each device, from which eight parameters describing keratometry and astigmatism were derived. Repeatability was assessed using intrasession, within-subject analysis of variance. Agreement was evaluated between pairs of devices with Bland- Altman plots and 95% confidence intervals. RESULTS: The repeatability values were good for all three devices, although slightly worse for the Cassini than for the other two devices for steep, flat, and mean keratometry. The EyeSys showed worse repeatability for the astigmatism axis. EyeSys and Pentacam agreed well with each other in terms of mean keratometry, whereas the Cassini gave consistently higher values by 0.52 diopters (D) when compared with the EyeSys (P < .05, paired t test) and by 0.38 D when compared with the Pentacam (P < .05, paired t test). The Cassini provided similar repeatability values (2.31°) for the astigmatism axis to the Pentacam (2.22°), in contrast to the EyeSys, which produced much more variable axes (9.0°) (P < .05, paired t test). CONCLUSIONS: Overall, the three devices display comparable repeatability. The one exception is the astigmatism axis measurement of the EyeSys. The Cassini provides higher keratometry values than the other two devices, but the astigmatism axis agrees well with that provided by the Pentacam.

Iris atrophy and erosion caused by an anterior-chamber angle-supported phakic intraocular lens.

UNLABELLED: We report a case in which an angle-supported phakic IOL was implanted to correct high myopia. Subsequently, the patient experienced photophobia, glare, halo, and loss of visual acuity and became concerned about the cosmetically deforming aspect of her eye. Findings included endothelial cell loss, cataract, pupil ovalization, and severe iris atrophy. The pIOL was removed and cataract surgery was performed, followed by implantation of a bag-in-the-lens IOL, but successful surgical repair of the iris was not possible because of severe iris atrophy. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Results of a phase I/II clinical trial: standardized, non-xenogenic, cultivated limbal stem cell transplantation.

BACKGROUND: To determine if a standardized, non-xenogenic, reduced manipulation cultivation and surgical transplantation of limbal stem cell grafts is a safe and effective treatment option for patients with total and partial limbal stem cell deficiency. METHODS: In vitro cellular outgrowth and phenotype of the limbal epithelial cell and composite grafts were validated using a new protocol. Patients received either autologous (n = 15) or allogenic (n = 3) explants cultured using a standardized protocol free from xenogenic products. The resulting grafts were transplanted using a reduced manipulation surgical technique. RESULTS: The majority of cells (>50%) displayed a progenitor phenotype typified by positive immunofluorescence for ∆Np63, CK14 and ABCG2 and low immunofluorescence for CK3/12 and desmoglein 3 proteins. The surgical protocol was designed to minimize manipulation and the graft itself was secured without sutures. The transplant recipients were followed for a mean of 24 months. Twelve of the 18 transplant recipients were graded as anatomically successful (67%), based on the defined success parameters. There was a significant reduction in corneal neovascularization, which was accompanied by an improvement in pain though not photophobia or central corneal opacity post transplant. The transplantation protocol showed no measureable effect on visual acuity. CONCLUSION: We conclude that this standardized culture system and surgical approach is safe and effective in reducing corneal neovascularization. The technique is free from animal contaminants and maintains a large proportion of progenitor cells. Although this technique did not improve visual function, restoring a functional epithelial cell layer and reducing corneal neovascularization provides an improved platform for a penetrating keratoplasty to ultimately improve visual function.