Congenital Corneal Opacities in a Cornea Referral Practice

Long-Term Follow-Up of Pediatric Excimer Laser-Assisted Penetrating Keratoplasty for Congenital Stromal Corneal Dystrophy

PURPOSE

The purpose of this study was to highlight characteristic clinical and microscopic findings and report the long-term follow-up of pediatric excimer laser-assisted penetrating keratoplasty (excimer-PKP) for congenital stromal corneal dystrophy (CSCD).

METHODS

A 2-year-old Greek child presented with CSCD at our department. Clinical examination showed bilateral flake-like whitish corneal opacities affecting the entire corneal stroma up to the limbus. Genetic testing identified a mutation of the decorin gene (c.962delA). The variant was not present in the parents and represented a de novo mutation. The uncorrected visual acuity was 20/100 in both eyes. Excimer-PKP (8.0/8.1 mm) was performed on the right eye at the age of 2.5 years and on the left eye at the age of 3 years. Postoperatively, alternating occlusion treatment was performed.

RESULTS

The light microscopic examination demonstrated a disorganized extracellular matrix of the corneal stroma characterized by a prominent irregular arrangement of stromal collagen lamellae with large interlamellar clefts containing ground substance, highlighted by periodic acid-Schiff- and Alcian blue-positive reaction detecting acid mucopolysaccharides. Electron microscopy showed disorganization and caliber variation of collagen lamellae and thin filaments within an electron-lucent ground substance. The postoperative course was unremarkable. Both grafts remained completely clear 14 years postoperatively. Corneal tomography showed moderate regular astigmatism with normal corneal thickness. The corrected distance visual acuity was 20/25 in both eyes.

CONCLUSIONS

Excimer-PKP for CSCD might be associated with excellent long-term results and a good prognosis, particularly when the primary surgery is performed at a very young age. However, this requires close postoperative follow-up examinations by an experienced pediatric ophthalmologist to avoid severe amblyopia.

Birth prevalence and characteristics of congenital corneal opacities

PURPOSE/AIM

To report the birth prevalence and natural history of congenital corneal opacities among a population-based cohort of children.

MATERIALS AND METHODS

The medical records of patients <5 years diagnosed with a congenital onset corneal opacity while residing in Olmsted County, Minnesota, from January 1, 1977, through December 31, 2016, were retrospectively reviewed.

RESULTS

Fourteen patients were diagnosed with a congenital corneal opacity during the 40-year study period for a birth prevalence of 1 in 5188 live births. The mean age at diagnosis was 7.5 months (range 0-48 months) and 9 (64.3%) were males. Four patients had congenital glaucoma, 4 had limbal dermoids, 2 had sclerocornea, and 1 patient each had Descemet's tear from birth trauma, herpes simplex virus type 1 keratitis, corneal leukoma, and an undiagnosed scar. Six (42.8%) patients required treatment for their underlying corneal opacity including the four patients with congenital glaucoma. The other 8 (57.1%) patients had a clear central axis. Four (28.6%) of 14 patients required amblyopia therapy, and 4 (28.6%) developed strabismus. Four (28.6%) patients had associated systemic conditions. During a mean follow up of 5.4 years (range 1.3-27.0 years), the median best corrected visual acuity (BCVA) was logmar 0.16 (20/25) (range 20/20-hand motion) with one patient with unilateral BCVA less than 20/60 and one patient with bilateral BCVA less than 20/60.

CONCLUSIONS

In this 40-year cohort, congenital corneal opacities were relatively rare and the result of a variety of disorders. Although amblyopia and strabismus occurred commonly, most patients had good visual outcomes.

General Treatment and Ophthalmic Management of Peters' Anomaly

Peters' anomaly (PA) is a manifestation of complex disorders in the development of the anterior segment of the eye. The most recognizable feature of the disease is a doughnut-shaped central corneal opacity and adhesions between the opacity and underlying iris. Glaucoma is observed in 30-70% of patients, with up to 50% of the patients showing concomitant vision-threatening disorders. Up to 60% of patients have systemic abnormalities or developmental delays. Being a rare malformation, PA is one of the most common congenital indications for corneal transplantation in infants. Penetrating keratoplasty is used as the primary method of treatment in cases with corneal opacification of a degree that forbids visual development in both eyes. The heterogeneity of co-occurring ophthalmic and systemic malformations in the spectrum of PA determines the wide range of success, defined by various endpoints: graft clarity or visual acuity. Although surgical advancement has made corneal grafting possible in younger children, it has a higher graft failure rate and worse visual prognosis than adult keratoplasty. Optical sector iridectomy, pupil dilation, or cornea rotation can alternatively be performed. Satisfying results of pediatric keratoprosthesis in particular cases of PA have been described. Postoperative treatment of PA aims to maintain a clear optical pathway and prevent amblyopia. This article therefore aims at reporting the ophthalmic treatment and need for multidisciplinary management of PA, including pharmacological and surgical treatment.

Clinical and diagnostic imaging profile of three anterior segment dysgenesis disorders presenting with infantile corneal opacities

PURPOSE

To describe three anterior segment dysgenesis disorders with infantile corneal opacities, namely, congenital hereditary endothelial dystrophy (CHED), primary congenital glaucoma (PCG), and Peters anomaly (PA) in terms of clinical characteristics, histopathology, genetic association, and diagnostic imaging profiles using imaging modalities such as ultrasound biomicroscopy (UBM) and microscope-integrated intraoperative optical coherence tomography (i-OCT).

MATERIALS AND METHODS

Seventy-four eyes with 22 eyes of CHED, 28 eyes of PA, and 24 eyes of PCG were clinically evaluated and underwent imaging using UBM and i-OCT. Corneal buttons of 16 operated patients underwent histopathological analysis, while genetic analysis was done in 23 patients using whole-exome sequencing.

RESULTS

Corneal diameters (CD) and UBM parameters like anterior chamber depth (ACD), iris thickness (IT), and ciliary body (CB) thickness revealed a statistically significant difference between the three categories. In PA, 9 eyes had a third rare phenotype with only a posterior corneal defect with no iris adhesions. Genetic mutations were seen in all tested patients with CHED, in 83.3% of patients with PCG, and in 80% of patients with the third type of PA. i-OCT helped in the characterization of corneal opacity, identification of posterior corneal defects, iridocorneal adhesions, and contour of Descemet's membrane.

CONCLUSION

Overlapping phenotypes of the above disorders cause a diagnostic dilemma and parameters like CDs, UBM ACD, IT, and CB thickness help differentiate between them. i-OCT can help in classifying the diseases in a high resolution, non-contact manner, and can better delineate corneal characteristics. The rare third type of PA phenotype may have a genetic association.

Overview of sclerocornea

Sclerocornea is a rare non-progressive, non-inflammatory usually bilateral congenital corneal opacity that can be associated with both ocular and systemic abnormalities. It could be inherited in 50% of cases. Ill-defined limbal architecture and vascularization in association with ocular comorbidities results in poor outcomes with corneal transplantation. This narrative review summarizes the current literature on etiology and clinical presentation in sclerocornea. With regards to keratoplasty, it focusses on key elements in decision making, highlights the role of investigations and discusses practical surgical pearls to enhance outcome of keratoplasty in these eyes.

Peters Anomaly: Novel Non-Invasive Alternatives to Penetrating Keratoplasty

BACKGROUND

Peters' anomaly (PA) is the most commonly encountered congenital corneal opacity (CCO) and displays a wide phenotypical range. The relatively recent adoption of high-quality anterior segment imaging in the form of high-frequency ultrasound biomicroscopy and anterior segment optical coherence tomography has aided in the accurate diagnosis of CCOs, facilitated distinction of PA from "pseudo-Peters' anomaly," and aided in prognostication and surgical risk stratification in PA. While the definitive management of PA, especially the more severe forms, is penetrating keratoplasty (PK), long-term success rates have overall been disappointing. This spurred the development of more non-invasive procedures, such as optical iridectomy and the more recently described selective endothelial removal, which represent viable alternatives to PK, at least in the less severe phenotypes of PA.

METHODS

Literature searches for the components of this review were performed using PubMed, in September 2021. The following keywords and their iterations were employed for the searches: "Peters' anomaly," "anterior segment dysgenesis," "kerato-irido-lenticular dysgenesis," "congenital corneal opacities." These were entered into the PubMed search engine, revealing 2852 related articles. The inclusion criteria included publications in the English language, specific to Peters' anomaly. Fifty-five studies that were published as systematic reviews or as nonrandomized comparative studies (cohort or case series) on the topic of Peters' anomaly were finally selected for this review.

RESULTS

This review provides a summary of Peters' anomaly in the context of advances in diagnosis, classification, and genotype-phenotype correlation of congenital corneal opacities, with a focus on penetrating keratoplasty, its outcomes, and non-invasive surgical options. While conservative therapies such as spontaneous clearing, mydriatic eye drops, and optical iridectomy may have variable success in milder variants of PA, penetrating keratoplasty in these eyes is fraught with several challenges and typically results in poor long-term functional outcomes. The management strategy depends on several variables such as phenotypical severity of PA, laterality, age at presentation, and capacity to adhere to the follow-up schedule. Notwithstanding the choice of treatment, it is essential that early and aggressive amblyopia therapy, a thorough systemic examination, and appropriate referral are undertaken for all patients of PA.

CONCLUSION

Peters' anomaly has seen recent advances in diagnosis, but treatment options remain limited. Focus directed towards less-invasive alternatives to keratoplasty may yield better functional outcomes.

Update on Pediatric Corneal Diseases and Keratoplasty

Managing pediatric corneal disorders is challenging as the prognosis of pediatric keratoplasty depends on several factors. Advancements in the genetic basis of congenital corneal diseases and investigations in congenital corneal conditions provide a better understanding of pediatric corneal conditions. Surgeons performing keratoplasty in children now have a choice of various techniques. Evolving surgical techniques of anterior lamellar and endothelial keratoplasties has expanded the management interventions in these pediatric corneal morbidity conditions; however, considerable concerns still exist in association with corneal transplantation in infants and children. Outcomes in pediatric keratoplasty depend upon the preoperative indications, the timing of surgical intervention, intraoperative and postoperative factors including the patient/care givers' compliance. Factors such as low scleral rigidity, higher rate of graft failure, need for frequent examinations under anesthesia, and difficulty in optimal visual acuity assessment still remain a considerable challenge in pediatric scenarios. In children, deprivation amblyopia as a result of the corneal opacification can adversely affect visual development, causing dense amblyopia. Outcomes to surgical interventions for management of corneal opacification in children is further compromised by the pre-existing amblyopia apart from the concerns of refractive outcome of the graft. Graft rejection, graft infection, amblyopia, and glaucoma continue to be serious concerns. In recent years both anterior and posterior lamellar keratoplasty techniques are being increasingly performed in pediatric eyes, which offer advantages in the form of lower risk of graft rejection. The timing of surgery, careful case selection, cautious intraoperative approach, and optimal postoperative management can improve the anatomical and functional outcome in difficult cases.

Case report of the rare Peters' anomaly complicated with Axenfeld-Rieger syndrome: A case report and brief review of the literature

INTRODUCTION

Peters' anomaly (PA) and Axenfeld-Rieger syndrome (ARS) are typical classifications of anterior segment dysgenesis (ASD) and ascribed to congenital eye diseases that encompass developmental defects in anterior segment structures. The aim of this study is to discuss the unusual association between PA and ARS and to determine the results of penetrating keratoplasty combined with extracapsular cataract extraction and anterior vitrectomy for this unusual ophthalmic phenotype.

PATIENT CONCERNS

A 72-year-old female was referred to Changzhou No. 2 People's Hospital for a progressive decrease in visual acuity in both eyes in the past few decades.

DIAGNOSES

The patient was diagnosed with PA with cone-shaped polar cataracts in the left eye based on a series of ophthalmic examinations. ARS with retinal detachment was diagnosed in the right eye 2 years prior.

INTERVENTIONS

Penetrating keratoplasty combined with extracapsular cataract extraction and anterior vitrectomy were performed to manage PA with cataracts in the left eye.

OUTCOMES

Her best corrected visual acuity did not improve significantly after the operation. Patients with ARS and PA should be treated cautiously because of fundus lesions.

CONCLUSION

This study revealed that cases with PA accompanied by iridocorneal adhesions, or other ocular anomalies, need to be treated cautiously for a very low success rate. It is of reference value for the evaluation of treatment prognosis for this joint occurrence of ophthalmic phenotypes.

Possible association between viral infection and poor survival of the corneal graft after penetrating keratoplasty in patients with congenital corneal opacity: a cohort study

BACKGROUND

Congenital corneal opacity (CCO) is a rare disorder. Penetrating keratoplasty (PK) is the main surgical option for CCO, but many factors affect graft survival. Therefore, this study aimed to perform a virological examination of CCO specimens after PK to explore the relationship between virological factors and graft survival after PK.

METHODS

This prospective study included consecutive patients (<6 months of age) diagnosed with CCO and treated with PK at Beijing Tongren Hospital from August 2017 to January 2018. Next-generation sequencing was used to detect viral DNA in the CCO specimens. The survival of the primary graft was analysed using the Kaplan-Meier method.

RESULTS

Overall, 24 eyes of 24 infants were treated with PK during the study period. The mean age at surgery was 4.8±1.1 months. Epstein-Barr virus DNA was detected in two specimens, varicella-zoster virus DNA in one specimen, herpes simplex virus DNA in three specimens and cytomegalovirus DNA in one specimen. In the virus-positive group, only one (14.3%) graft remained clear during follow-up. In contrast, in the virus-negative group (n=17), 13 (76.5%) grafts were still clear at the last follow-up. The mean survival of the grafts in the virus-positive group was significantly shorter than in the virus-negative group (11.0±9.8 months vs 27.1±7.7, p<0.001).

CONCLUSION

The presence of viral DNA in CCO specimens might be associated with poor graft survival after PK.

Transcriptome from opaque cornea of Fanconi anemia patient uncovers fibrosis and two connected players

Congenital corneal opacities (CCO) are a group of blinding corneal disorders, where the underlying molecular mechanisms are poorly understood. Phenotyping through specialized imaging and histopathology analysis, together with assessment of key transcriptomic changes (including glycosaminoglycan metabolic enzymes) in cornea(s) with CCO from a case of Fanconi anemia is the approach taken in this study to identify causal mechanisms. Based on our findings, we propose a novel mechanism and two key players contributing to CCO.

A systematic review of ultrasound biomicroscopy use in pediatric ophthalmology

Ultrasound biomicroscopy (UBM) is the only available option for noninvasive, high-resolution imaging of the intricate iridociliary complex, and for anterior segment imaging with corneal haze or opacity. While these unique features render UBM essential for specific types of trauma, congenital anomalies, and anterior segment tumors, UBM imaging has found clinical utility in a broad spectrum of diseases for structural assessments not limited to the anterior intraocular anatomy, but also for eyelid and orbit anatomy. This imaging tool has a very specific niche in the pediatric population where anterior segment disease can be accompanied by corneal opacity or clouding, and anomalies posterior to the iris may be present. Pediatric patients present additional diagnostic challenges. They are often unable to offer detailed histories or fully cooperate with examination, thus amplifying the need for high-resolution imaging. This purpose of this systematic review is to identify and synthesize the body of literature involving use of UBM to describe, evaluate, diagnose, or optimize treatment of pediatric ocular disease. The collated peer-reviewed research details the utility of this imaging modality, clarifies the structures and diseases most relevant for this tool, and describes quantitative and qualitative features of UBM imaging among pediatric subjects. This summary will include information about the specific applications available to enhance clinical care for pediatric eye disease.

Long-Term Visual Outcomes and Clinical Course of Patients With Peters Anomaly

PURPOSE

To present long-term clinical and visual outcomes of patients with Peters anomaly.

METHODS

The charts of all patients diagnosed with Peters anomaly from January 2000 to December 2012 were reviewed retrospectively. Peters anomaly was classified as type I (with no lens involvement) or type II (presence of keratolenticular adhesions or cataract), with further severity grading to mild, moderate, and severe disease depending on corneal opacity location and size. Mild cases were observed. Moderate cases were managed with pupillary dilation either pharmacologically or surgically. Penetrating keratoplasty (PKP) was reserved for more severe opacity. The main outcome measures were final best spectacle-corrected visual acuity (BSCVA), incidence of glaucoma, graft survival, and nystagmus rates.

RESULTS

Sixty eyes of 40 patients were included in the study. The median age of patients at presentation was 0.5 ± 20.7 months (range, 0.0-111.0 months), with a mean follow-up time of 75.8 ± 52.9 months (range, 12.1-225.3 months). Overall, final best spectacle-corrected visual acuity ranged from 0.1 logMAR to no light perception with 33 eyes (55.9%) achieving vision of 1.0 logMAR or better. Clear grafts at the last follow-up were obtained in 67.6% (25/37) of transplanted eyes, 76.0% (19/25) in Peters type I, and 50.0% (6/12) in Peters type II (P = 0.11). The probability of a clear graft at 10 years was 74.2% and 38.9% for type I and type II, respectively. Glaucoma was diagnosed in 33.3% eyes, 90.0% of which occurred after PKP. Nystagmus was highly associated with PKP intervention, occurring in 81.1% (30/37) of eyes undergoing PKP compared with 34.8% (8/23) of eyes with no PKP (P = 0.0003).

CONCLUSIONS

Visual rehabilitation in Peters anomaly remains a challenge, but outcomes can be optimized using a comprehensive clinical management algorithm according to disease severity.

Outcome of a penetrating keratoplasty in a 3-month-old child with sclerocornea

Sclerocornea is a rare congenital anomaly with clouding of the peripheral cornea that possibly extends up to the center of the cornea. Characteristically, a clear distinction (limbus) between sclera and cornea is lacking. Early surgical treatment is essential for preventing amblyopia, but penetrating keratoplasty in children carries a relatively high risk of complications. Especially for sclerocornea, penetrating keratoplasty has generally been reported to have a poor surgical outcome and a high risk of complications, including corneoscleral adhesions. Here, we report the 4-year follow-up on a child with sclerocornea, who was successfully operated on at the age of 3 months and had a favorable outcome. Our findings suggest that in some cases, penetrating keratoplasty may be an option to treat sclerocornea in young children.

Ultrasound Biomicroscopy Detects Peters' Anomaly and Rieger's Anomaly in Infants

AIM

Congenital corneal opacities (CCOs) are the major causes of early visual deprivation in infants. Balloon ultrasound biomicroscopy (UBM) examination is an effective method to diagnose CCO. However, whether it is suitable for children examination is still unknown.

METHODS

26 Peters' anomaly (PA) or Rieger's anomaly (RA) infants with congenital corneal opacities (CCO) (40 eyes) underwent UBM examinations to study their imaging features.

RESULTS

Based on the results, they were divided into UBM Dx-Type I: Descemet's membrane (DM) and endothelium have heterogenous or discontinuous echo accompanied with corneal stroma echo-enhanced or shallow anterior chamber. Type II: Type I alteration plus abnormal strand of iris extended to the border of the posterior corneal defect or iridocorneal adhesion. Type III: Type I or II combined with the abnormal hyperechoic lens, lens luxation, or keratolenticular adhesion. Type IV: echoes of the DM and the endothelium are continuous, corneal stroma echo is enhanced, and an abnormal strand of peripheral iris extends to the prominent Schwalbe line, accompanied by iris stroma or pupil heteromorphism and a shallow or flat anterior chamber.

CONCLUSION

UBM not only could accurately evaluate the anterior segment abnormalities in CCO infants but also would be a step forward for the management of PA- and RA-associated CCO.

Clinicopathologic Features and Treatment Characteristics of Congenital Corneal Opacity Infants and Children Aged 3 Years or Less: A Retrospective Single Institution Analysis

OBJECTIVE

In this retrospective single institution study, we investigated the clinicopathologic features and treatment characteristics of 90 patients with congenital corneal opacities (CCO) (117 eyes) who were 3 years and younger and treated at our hospital.

SUBJECT AND METHODS

We reviewed the clinical data of patients with CCO who presented for the first time for treatment at our hospital between January 1, 2017, and December 31, 2017. CCO were classified using the "STUMPED" (Sclerocornea, Tears in Descement's membrane, Metabolic, Peters, Endothelial dystrophy and Dermoid) method and confirmed by pathological examination. -Results: Seventy percent of the patients had unilateral CCO. Iridocorneal adhesions (61 eyes, 52.1%) and cataracts (22 eyes, 18.8%) were the 2 most common ocular abnormalities. Systemic abnormalities were present in 5 patients (5.6%), including growth retardation (4 patients) and congenital brain defects (1 patient). Eighty-five eyes (72.6%) underwent penetrating keratoplasty (PK), and lamellar keratoplasty (LK) was performed in 30 (25.6%) eyes. Forty-seven (95.9%) eyes with Peters anomaly and all 16 eyes with sclerocornea received PK, and all 24 eyes with dermoids were treated with LK.

CONCLUSION

Our study demonstrates that CCO has varied manifestations in infants and young children in China. A thorough medical history, careful clinical examination, and the use of accessory examinations such as ultrasound biomicroscopy are critical for the accurate diagnosis and classification of CCO and to provide guidance on therapeutic choices.

Selective Endothelial Removal for Peters Anomaly

PURPOSE

Peters anomaly is the most common cause of congenital corneal opacities. Although conservative management is often ineffective except in mild cases, surgical intervention in the form of penetrating keratoplasty is fraught with unpredictability and often has unacceptable postoperative outcomes. As such, there is a need to explore alternative surgical interventions that may possibly improve the postoperative visual prognosis in these patients. In this report, we present a case of type 1 Peters anomaly treated by selective endothelial removal without corneal tissue transplantation.

METHODS

A case report with literature review.

RESULTS

A 21-month-old child, who presented with unilateral type 1 Peters anomaly, underwent selective endothelial removal without corneal tissue transplantation for the treatment of her condition. The patient demonstrated excellent anatomical and visual recovery after the procedure over a 1-year period. Her visual acuity had improved from 20/960 preoperatively to 20/30 during the latest review. Postoperative recovery was not complicated by the development of any sight-threatening complications, and she has been successfully weaned off all topical and systemic medications.

CONCLUSIONS

Selective endothelial removal can potentially be used to treat cases of type 1 Peters anomaly.

[Importance of investigation of fetal eyes : Supplement to fetal autopsy]

The investigation of fetal eyes is a subspecialty, which is performed by only a few ophthalmic pathologists and pathologists in specialized centers. If a certain fetal syndrome is suspected, the fetal eyes should be removed and submitted for ophthalmic pathological investigation in a specialized center. This can provide additional diagnostic information allowing a final classification of a syndrome and the comprehensive genetic counselling of parents with respect to future pregnancies. This article provides an overview of the histopathological findings in fetal eyes, which are of particular relevance for the pediatric pathological autopsy. In addition, the basic points of ocular development, the preparation of fetal eyes and frequent artifacts are presented.

The challenging management of pediatric corneal transplantation: an overview of surgical and clinical experiences

PURPOSE

Pediatric keratoplasty is an immense challenge because of the technical complexity of the procedure and the high risk of rejection in young graft recipients. Our aim is to describe the major indications and appropriate timing of corneal transplantation intervention, including a report of our experience and surgical tips, in conjunction with the current literature.

METHODS

Review of the literature on indications for keratoplasty in pediatric patients classified as: congenital, traumatic and acquired non-traumatic opacities. We additionally explored the challenges corneal surgeons face in performing this type of surgery and review the most pressing transplant-related problems and their management.

RESULTS

Outcomes after pediatric keratoplasty, in terms of visual development, restoration and clarity of the graft, are influenced by peri-operative local and systemic conditions and factors, and by intraoperative management of the transplantation procedure itself.

CONCLUSION

Pediatric corneal transplantation is a critical tool for visual restoration and development in young patients with corneal opacities, particularly during the critical period of visual development. Successful management of the significant challenges associated with pediatric keratoplasty requires customized clinical and surgical management of each patient with particular attention paid to proper post-operative rehabilitation.

Bilateral cloudy cornea: is the usual suspect congenital hereditary endothelial dystrophy or stromal dystrophy?

We provide the diagnosis, treatment and follow-up period of a patient with cloudy cornea in both eyes from birth. A 4-year-old girl presented with blurring in both eyes. Penetrating keratoplasty (PK) was performed with the preliminary diagnosis of congenital hereditary endothelial dystrophy in June 2012. According to the pathology report for extracted host tissue, the Descemet's membrane (DM) and endothelium were healthy and diagnosis was reported to be congenital hereditary stromal dystrophy. Deep anterior lamellar keratoplasty was performed on the left eye. The DM was transparent at follow-up. Cornea transplantation is the only choice to provide visual rehabilitation in children with congenital cloudy cornea. However, it is known that the prognosis of traditional PK in the paediatric age group is not good. Therefore, when using alternative keratoplasty (deep anterior lamellar keratoplasty, Descemet's stripping automated endothelial keratoplasty) options, pathological examination of the host tissue should be made.

Dental stem cells: a future asset of ocular cell therapy

Regenerative medicine using patient's own stem cells (SCs) to repair dysfunctional tissues is an attractive approach to complement surgical and pharmacological treatments for aging and degenerative disorders. Recently, dental SCs have drawn much attention owing to their accessibility, plasticity and applicability for regenerative use not only for dental, but also other body tissues. In ophthalmology, there has been increasing interest to differentiate dental pulp SC and periodontal ligament SC (PDLSC) towards ocular lineage. Both can commit to retinal fate expressing eye field transcription factors and generate rhodopsin-positive photoreceptor-like cells. This proposes a novel therapeutic alternative for retinal degeneration diseases. Moreover, as PDLSC shares similar cranial neural crest origin and proteoglycan secretion with corneal stromal keratoctyes and corneal endothelial cells, this offers the possibility of differentiating PDLSC to these corneal cell types. The advance could lead to a shift in the medical management of corneal opacities and endothelial disorders from highly invasive corneal transplantation using limited donor tissue to cell therapy utilizing autologous cells. This article provides an overview of dental SC research and the perspective of utilizing dental SCs for ocular regenerative medicine.

Eye disorders in newborn infants (excluding retinopathy of prematurity)

A screening eye examination is an essential part of the newborn assessment. The detection of many ocular disorders in newborn infants can be achieved through careful observation of the infant's visual behaviour and the use of a direct ophthalmoscope to assess the ocular structures and check the red reflex. Early diagnosis and subspecialty referral can have a critical impact on the prognosis for many ocular conditions, including potentially blinding but treatable conditions such as congenital cataracts, life-threatening malignancies such as retinoblastoma and harbingers of disease elsewhere such as sporadic aniridia and its association with the development of Wilms tumour.

Molecular description of eye defects in the zebrafish Pax6b mutant, sunrise, reveals a Pax6b-dependent genetic network in the developing anterior chamber

The cornea is a central component of the camera eye of vertebrates and even slight corneal disturbances severely affect vision. The transcription factor PAX6 is required for normal eye development, namely the proper separation of the lens from the developing cornea and the formation of the iris and anterior chamber. Human PAX6 mutations are associated with severe ocular disorders such as aniridia, Peters anomaly and chronic limbal stem cell insufficiency. To develop the zebrafish as a model for corneal disease, we first performed transcriptome and in situ expression analysis to identify marker genes to characterise the cornea in normal and pathological conditions. We show that, at 7 days post fertilisation (dpf), the zebrafish cornea expresses the majority of marker genes (67/84 tested genes) found also expressed in the cornea of juvenile and adult stages. We also characterised homozygous pax6b mutants. Mutant embryos have a thick cornea, iris hypoplasia, a shallow anterior chamber and a small lens. Ultrastructure analysis revealed a disrupted corneal endothelium. pax6b mutants show loss of corneal epithelial gene expression including regulatory genes (sox3, tfap2a, foxc1a and pitx2). In contrast, several genes (pitx2, ctnnb2, dcn and fabp7a) were ectopically expressed in the malformed corneal endothelium. Lack of pax6b function leads to severe disturbance of the corneal gene regulatory programme.

Cataract surgery in children with congenital keratolenticular adhesion (Peters anomaly type 2)

PURPOSE

To report the visual and surgical outcomes after cataract surgery in children with keratolenticular adhesion (Peters anomaly type 2).

METHODS

The medical records of consecutive patients with keratolenticular adhesion (KLA) with partial (iris defects)/complete aniridia were retrospectively reviewed. Cataract surgery (in-the-bag irrigation and aspiration) with or without intraocular lens implantation and with or without broad iridectomy was performed. The main outcome measures were postoperative visual acuity, complications, and progression of corneal opacity.

RESULTS

The study included 4 eyes of 3 patients ranging in age from 3 months to 7 years. The mean age at cataract surgery was 37 months; the median, 24 months (range, 3-84 months). The mean follow-up was 3.3 years and median was 2 years (range, 2-6 years). Preoperative visual acuity ranged from fixing and following objects to 20/200. Only 1 patient had PAX6 mutation-confirmed aniridia. The other 2 patients had partial iris defects. All eyes improved in visual acuity ranging from counting fingers at 3 feet to 20/60. There was no progression of corneal opacity. There were no postoperative complications.

CONCLUSIONS

Children with KLA with complete or partial iris defects with localized corneal opacity and cataract can achieve satisfactory visual outcomes by undergoing meticulous lensectomy with or without iridectomy.

Anterior segment developmental anomalies in a 33-week-old fetus with MIDAS syndrome

We report anterior segment abnormalities in both eyes of a 33-week-old fetus endorsing the diagnosis of MIDAS (microphthalmia, dermal aplasia, and sclerocornea) syndrome. After abortion, the fetus was examined by a standard pediatric autopsy that included macroscopic and microscopic examination of both eyes. Postmortem findings included craniofacial stigmata (such as hypertelorism, a flat nose and low-set ears) and an agenesis of the corpus callosum. Array comparative genomic hybridization revealed a deletion of the short arm of the X chromosome (region Xp22.2 to p22.32). Ophthalmopathologic examination of the eyes revealed microphthalmia with anterior segment developmental anomalies, in particular sclerocornea and Peters' anomaly, respectively. General pathology findings plus the ocular findings allowed the diagnosis of MIDAS syndrome. A discussion of differential diagnoses is provided. This case report indicates that ophthalmopathologic investigation of fetal eyes can be of great value for the further classification of syndromes.

Clinical features of anterior segment dysgenesis associated with congenital corneal opacities

PURPOSE

Anterior segment dysgenesis is one of the main causes of congenital corneal opacities. In this study, we investigated the clinical features and visual outcomes of patients with anterior segment dysgenesis in a large number of cases.

METHODS

The medical records of patients with congenital corneal opacities in relation to anterior segment dysgenesis seen in the National Center for Child Health and Development, Japan, between April 2002 and October 2009, were retrospectively studied.

RESULTS

Records of 220 eyes of 139 patients were reviewed. Mean follow-up period was 5 years. Clinical diagnoses were Peters anomaly (72.7%), anterior staphyloma (11.4%), Rieger anomaly (7.7%), sclerocornea (6.4%), and others (1.8%). Visual acuity was measured in 61 patients. The best-corrected visual acuity in the better eye of bilaterally involved patients was 20/60 to 20/1000 (low vision according to the International Classification of Diseases, Ninth Revision, Clinical Modification) in 43.2% and less than 20/1000 (legally blind) in 24.3%. Fundus examination was performed in 82 eyes, and disorders were seen in 12 (12 of 82; 14.6%). Systemic abnormalities were present in 35 patients (35 of 139; 25.2%); a family history was present in 5 patients (5 of 139; 3.6%). Of the 160 eyes of 109 patients with Peters anomaly, 51 patients (51 of 109; 46.8%) had bilateral Peters anomaly, 30 (30 of 109; 27.5%) had fellow eyes that were normal, and 28 (28 of 109, 25.7%) showed other abnormal ocular findings in the fellow eye.

CONCLUSIONS

Anterior segment dysgenesis shows diverse clinical features, various severities of corneal opacities, and visual outcomes. Further understanding of the disease as an abnormality during embryogenesis and neural crest cell differentiations may be required.

Should unilateral congenital corneal opacities in Peters' anomaly be grafted?

PURPOSE

To evaluate the surgical outcomes and visual results after penetrating keratoplasty for congenital unilateral corneal opacities in Peters anomaly.

METHODS

This was a retrospective study of 14 children who underwent keratoplasty for a unilateral Peters anomaly between 1999 and 2009. All patients received a topical treatment of cyclosporine and corticosteroids. Suture ablation was performed between the first and second postoperative month and all patients had spectacle correction and amblyopia treatment. Age at time of surgery, posterior segment status evaluated by ultrasonography, axial length, preoperative intraocular pressure, fellow eye status, mean follow-up time, early and late complications, final graft outcome, refraction, and visual acuity upon the last visit were noted.

RESULTS

Mean age at the time of surgery was 9 months. Posterior segment was normal in all cases. Mean axial length was 18 mm and mean intraocular pressure was 11 mmHg. Mean follow-up was 30 months. Four children had graft rejection episodes, 2 of which responded to medication. Four underwent cataract surgery, one developed pupil deformation requiring a pupilloplasty, and 2 cases were complicated by surgical glaucoma. A total of 11 eyes (78.6%) had clear grafts at the end of the follow-up. Mean spherical equivalent was -1.5 D. Visual acuity was measurable in 3 cases and was 20/50 in one case, 20/63 in the second, and 20/2000 in the third. Concerning preverbal children, central, steady, and maintained fixation was found in 8 cases.

CONCLUSIONS

Operating on a unilateral congenital corneal opacity is a challenging decision and should be taken after explaining the need for long-term follow-up to the parents. Useful vision can be achieved and maintained after strict amblyopia therapy. A multidisciplinary ophthalmologic follow-up is necessary.

Boston Keratoprosthesis: expanding the boundaries

The Boston Keratoprosthesis (KPro) has enjoyed good results in the adult population, particularly through its rapid clearing of the visual axis, its excellent retention rate, and the paucity of postoperative complications in recent years. Design modifications, enhanced surgical technique, and improved postoperative management have made keratoprosthesis surgery a reality in the twenty-first century and an excellent alternative for poor PK candidates.

Large congenital corneal dermoid with spontaneous partial regression: the first report

PURPOSE

To report a spontaneous partial regression of a large congenital corneal dermoid in a newborn.

MATERIALS AND METHODS

Review and follow-up of the medical records of a female newborn presenting with a tumor mass of her right eye and no other congenital abnormalities. The child presented on the first day of life with a mushroom-shaped mass of 15 × 15 mm in diameter that involved the most of the cornea leaving a small clear portion superiorly. The mass protruded through the palpebral aperture. A diagnosis of corneal dermoid was made based on clinical presentation of the mass and radiographic and ultrasound findings. Enucleation of the right eye was discussed, but declined by parents.

RESULTS

During the first month of life, a spontaneous partial regression of the mass occurred, so that the patient was able to close the lids completely above the mass. This dermoid is the third type according to Mann's classification. Characterized by involvement of the entire anterior segment and lack of lens.

CONCLUSIONS

To the best of our knowledge, the case reported is the first documented spontaneous partial regression of a large corneal dermoid. Surgical excision at an early age may be recommended to avoid development of amblyopia and dramatic growth of the tumor. In our case the tumor regressed and surgical excision would have no impact on visual outcome. Future management of type III corneal dermoid needs to consider whether to perform surgery at an early stage or to recommend conservative management.

The epidemiology of cosmetic treatments for corneal opacities in a Korean population

Purpose

To describe etiologies and clinical characteristics of corneal opacities leading patients to seek cosmetic treatments.

Methods

The medical records of 401 patients who presented for cosmetic improvement in corneal opacities between May 2004 and July 2007 were retrospectively reviewed. The following parameters were analyzed: age, gender, cause of corneal opacity, time course of the corneal disease, associated diseases, prior and current cosmetic treatments, visual acuity, location and depth of the corneal opacity, and the presence of either corneal neovascularization or band keratopathy. A single practitioner examined all patients.

Results

The most common causes of corneal opacity were ocular trauma (203 eyes, 50.6%), retinal disease (62 eyes, 15.5%), measles (38 eyes, 9.5%), and congenital etiologies (22 eyes, 5.5%). Prior treatments included iris colored contact lenses (125 eyes, 31.1%) and corneal tattooing (34 eyes, 8.46%). A total of 321 of 401 eyes underwent cosmetic treatment for corneal opacities. The most common treatment performed after the primary visit was corneal tattooing (261 eyes, 64.92%).

Conclusions

This is the first study to investigate the causes and clinical characteristics of patients presenting for cosmetic treatment of corneal opacities rather than for functional improvement. Various cosmetic interventions are available for patients with corneal opacities, and these should be individualized for the needs of each patient.

Congenital hereditary endothelial dystrophy with progressive sensorineural deafness (Harboyan syndrome)

Harboyan syndrome is a degenerative corneal disorder defined as congenital hereditary endothelial dystrophy (CHED) accompanied by progressive, postlingual sensorineural hearing loss. To date, 24 cases from 11 families of various origin (Asian Indian, South American Indian, Sephardi Jewish, Brazilian Portuguese, Dutch, Gypsy, Moroccan, Dominican) have been reported. More than 50% of the reported cases have been associated with parental consanguinity. The ocular manifestations in Harboyan syndrome include diffuse bilateral corneal edema occurring with severe corneal clouding, blurred vision, visual loss and nystagmus. They are apparent at birth or within the neonatal period and are indistinguishable from those characteristic of the autosomal recessive CHED (CHED2). Hearing deficit in Harboyan is slowly progressive and typically found in patients 10-25 years old. There are no reported cases with prelinglual deafness, however, a significant hearing loss in children as young as 4 years old has been detected by audiometry, suggesting that hearing may be affected earlier, even at birth. Harboyan syndrome is caused by mutations in the SLC4A11 gene located at the CHED2 locus on chromosome 20p13-p12, indicating that CHED2 and Harboyan syndrome are allelic disorders. A total of 62 different SLC4A11 mutations have been reported in 98 families (92 CHED2 and 6 Harboyan). All reported cases have been consistent with autosomal recessive transmission. Diagnosis is based on clinical criteria, detailed ophthalmological assessment and audiometry. A molecular confirmation of the clinical diagnosis is feasible. A variety of genetic, metabolic, developmental and acquired diseases presenting with clouding of the cornea should be considered in the differential diagnosis (Peters anomaly, sclerocornea, limbal dermoids, congenital glaucoma). Audiometry must be performed to differentiate Harboyan syndrome from CHED2. Autosomal recessive types of CHED (CHED2 and Harboyan syndrome) should carefully be distinguished from the less severe autosomal dominant type CHED1. The ocular abnormalities in patients with Harboyan syndrome may be treated with topical hyperosmolar solutions. However, corneal transplantation (penetrating keratoplasty) represents definitive treatment. Corneal transplantation produces a substantial visual gain and has a relatively good surgical prognosis. Audiometric monitoring should be offered to all patients with CHED2. Hearing aids may be necessary in adolescence.

Corneal pathology in microphthalmia with linear skin defects syndrome

PURPOSE

To describe the histopathology of the cornea in microphthalmia with linear streaks (MLS) syndrome.

METHODS

Two patients with MLS syndrome underwent penetrating keratoplasty. This study describes the histopathology and investigates immunophenotype of the corneal extracellular matrix by using keratan sulfate and collagen type III antibodies.

RESULTS

Clinical examination revealed bilateral sclerocornea and characteristic skin changes. By light microscopy, central corneal stroma in both patients showed vascularization and irregular thick collagen lamellae typical of sclerocornea. In addition, corneal thinning, anterior synechiae, and the absence of the Descemet membrane were noted, which was suggestive of Peters anomaly. Diffuse and intense anti-keratan sulfate staining and minimal anti-collagen type III stromal staining were seen in both corneal buttons.

CONCLUSIONS

The cornea in MLS may clinically resemble sclerocornea. Histologic features resemble those previously described in sclerocornea and also seen in anterior segment dysgeneses. Keratan sulfate and collagen type III labeling suggests that the corneal extracellular matrix resembled cornea and not sclera.

Long-term visual prognosis in children after corneal transplant surgery for Peters anomaly type I

PURPOSE

To evaluate the long-term visual prognosis in children with corneal transplant surgery for Peters anomaly type I.

DESIGN

Retrospective review of interventional case series.

METHODS

Twenty-four children treated in a university-based practice were divided into two groups for analysis: a younger preverbal group and an older group of children three years of age or older. Children underwent corneal transplantation surgery (penetrating keratoplasty [PKP]) for Peters anomaly type I as infants (age range, two to 18 months). Visual acuity using Snellen or Allen charts and glaucoma and other complications were tabulated.

RESULTS

Twenty-four patients had Peters anomaly; 16 had unilateral disease, eight had bilateral disease. Thirty eyes underwent PKP. Average age at PKP was five months. The mean follow-up from PKP to the most recent visit was 78.9 months. Fifteen eyes (50%) were treated for glaucoma. Five transplants (17%) had graft rejection episodes; two of these failed and were regrafted. Six eyes (20%) required cataract surgery. One eye had a retinal detachment. Currently, 27 eyes (90%) have clear grafts. In the younger group of children, five of six grafts are clear (83%). In the older group of 24 eyes of verbal children, seven eyes (29%) have visual acuity ranging from 20/20 to 20/50, six (25%) have visual acuity ranging from 20/60 to 20/100, nine (38%) have visual acuity ranging from 20/200 to counting fingers, and two eyes (8%) have visual acuity of hand movements. In this group, nine of 12 eyes without glaucoma had visual acuity better than 20/100; only four of 11 eyes with glaucoma were better than 20/100.

CONCLUSIONS

Many children with PKP for Peters anomaly type I can experience good or functional vision in their operated eye. Children with glaucoma have a poorer visual prognosis.

Pediatric Keratoprosthesis

OBJECTIVE

To describe the authors' experience using keratoprosthesis to treat pediatric corneal opacity.

DESIGN

Nonrandomized, consecutive, retrospective interventional series.

PARTICIPANTS

Twenty-two eyes of 17 children with opaque corneas as a result of primary congenital disease and or previous failed keratoplasty.

METHODS

A retrospective review of pediatric patients with a history of corneal opacification treated with keratoprosthesis surgery.

MAIN OUTCOME MEASURES

Intraocular pressure, inflammation, clarity of the visual axis, visual acuity, refraction, complications, and retention of the prosthesis.

RESULTS

Twenty-two eyes of 17 patients 1.5 to 136 months of age underwent 23 keratoprosthesis procedures. The follow-up period was 220 patient months (range, 1-37 months; mean, 9.7 months). In both cases implanted with the AlphaCor (Argus Biomedical Pty. Ltd., Perth, Australia), the keratoprosthesis was not retained. In one instance, the prosthesis sustained traumatic dislocation and was replaced with a cadaver cornea. In the second instance, the intralamellar implant began to extrude and was replaced with a Boston keratoprosthesis. In all 21 Boston cases, the prosthesis was retained without dislocation or extrusion. The visual axis remained clear in 100% of cases, although retroprosthetic membranes were removed in 5 eyes. Reoperation was necessitated for management of concurrent glaucoma (n = 3) or retinopathy (n = 2). There were no instances of surface infection or endophthalmitis. In 7 instances where patient age was 4 years or more, visual acuity ranged from counting fingers to 20/30. In the remaining cases, all infants were able to follow light, fingers, and objects. Intraocular pressure was controlled in all cases.

CONCLUSIONS

Implantation of the Boston keratoprosthesis rapidly establishes and maintains a clear optical pathway and does not prejudice management of concurrent glaucoma or retinopathy. The device is retained without extrusion or rejection and is appropriate for the management of pediatric corneal opacity.

Mutations in laminin alpha 1 result in complex, lens-independent ocular phenotypes in zebrafish

We report phenotypic and genetic analyses of a recessive, larval lethal zebrafish mutant, bal(a69), characterized by severe eye defects and shortened body axis. The bal(a69) mutation was mapped to chromosome 24 near the laminin alpha 1 (lama1) gene. We analyzed the lama1 gene sequence within bal(a69) embryos and two allelic mutants, bal(arl) and bal(uw1). Missense (bal(a69)), nonsense (bal(arl)), and frameshift (bal(uw1)) alterations in lama1 were found to underlie the phenotypes. Extended analysis of bal(a69) ocular features revealed disrupted lens development with subsequent lens degeneration, focal cornea dysplasia, and hyaloid vasculature defects. Within the neural retina, the ganglion cells showed axonal projection defects and ectopic photoreceptor cells were noted at inner retinal locations. To address whether ocular anomalies were secondary to defects in lens differentiation, bal(a69) mutants were compared to embryos in which the lens vesicle was surgically removed. Our analysis suggests that many of the anterior and posterior ocular defects in bal(a69) are independent of the lens degeneration. Analysis of components of focal adhesion signaling complexes suggests that reduced focal adhesion kinase activation underlies the anterior segment dysgenesis in lama1 mutants. To assess adult ocular phenotypes associated with lama1 mutations, genetic mosaics were generated by transplanting labeled bal cells into ocular-fated regions of wild-type blastulas. Adult chimeric eyes displayed a range of defects including anterior segment dysgenesis and cataracts. Our analysis provides mechanistic insights into the developmental defects and ocular pathogenesis caused by mutations in laminin subunits.