Iris Pigment Epithelium Research Articles

Current Treatment Limitations in Age-Related Macular Degeneration and Future Approaches Based on Cell Therapy and Tissue Engineering

Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. With an ageing population, it is anticipated that the number of AMD cases will increase dramatically, making a solution to this debilitating disease an urgent requirement for the socioeconomic future of the European Union and worldwide. The present paper reviews the limitations of the current therapies as well as the socioeconomic impact of the AMD. There is currently no cure available for AMD, and even palliative treatments are rare. Treatment options show several side effects, are of high cost, and only treat the consequence, not the cause of the pathology. For that reason, many options involving cell therapy mainly based on retinal and iris pigment epithelium cells as well as stem cells are being tested. Moreover, tissue engineering strategies to design and manufacture scaffolds to mimic Bruch's membrane are very diverse and under investigation. Both alternative therapies are aimed to prevent and/or cure AMD and are reviewed herein.

Ambliopía secundaria a quiste de iris

Clinical caseA 5 year-old child diagnosed with moderate anisometropic amblyopia secondary to primary cyst of iris pigment epithelium. He was evaluated with ultrasound biomicroscopy (BMU) and optical coherence tomography (OCT) of anterior segment. DiscussionThe OCT, although with some limitations, is a useful tool to study the anterior segment. It is probably more recommendable than BMU in the childhood.

A New Age of Regenerative Medicine: Fusion of Tissue Engineering and Stem Cell Research

A New Age of Regenerative Medicine: Fusion of Tissue Engineering and Stem Cell Research

Retinal Stem Cells and Regeneration of Vision System

The vertebrate retina is a well-characterized model for studying neurogenesis. Retinal neurons and glia are generated in a conserved order from a pool of mutlipotent progenitor cells. During retinal development, retinal stem/progenitor cells (RPC) change their competency over time under the influence of intrinsic (such as transcriptional factors) and extrinsic factors (such as growth factors). In this review, we summarize the roles of these factors, together with the understanding of the signaling pathways that regulate eye development. The information about the interactions between intrinsic and extrinsic factors for retinal cell fate specification is useful to regenerate specific retinal neurons from RPCs. Recent studies have identified RPCs in the retina, which may have important implications in health and disease. Despite the recent advances in stem cell biology, our understanding of many aspects of RPCs in the eye remains limited. PRCs are present in the developing eye of all vertebrates and remain active in lower vertebrates throughout life. In mammals, however, PRCs are quiescent and exhibit very little activity and thus have low capacity for retinal regeneration. A number of different cellular sources of RPCs have been identified in the vertebrate retina. These include PRCs at the retinal margin, pigmented cells in the ciliary body, iris, and retinal pigment epithelium, and Müller cells within the retina. Because PRCs can be isolated and expanded from immature and mature eyes, it is possible now to study these cells in culture and after transplantation in the degenerated retinal tissue. We also examine current knowledge of intrinsic RPCs, and human embryonic stems and induced pluripotent stem cells as potential sources for cell transplant therapy to regenerate the diseased retina.

Peripheral Pigmented Placoid Corneal Endotheliopathy

To present a case series of peripheral pigmented placoid corneal endotheliopathy (PPPCE). A retrospective chart review of patient demographics, medical histories, and clinical characteristics was performed. Examinations included the following specialized imaging modalities: slit-lamp photography, gonioscopy, high-frequency ultrasound biomicroscopy, and anterior segment ocular coherence tomography. A PubMed and multiple corneal textbook literature search using the key words cornea, pigment, plaque, and endothelium revealed that no similar cases were reported. Five eyes in 4 asymptomatic female patients were affected. Their mean age was 53 years (range, 43-61 years), and 3 were of African American descent and 1 was of Hispanic descent. The PPPCE lesions had a vertical dimension of 0.2 to 1.7 mm and a horizontal dimension of 0.5 to 6.1 mm. All the PPPCE lesions were well demarcated, brown, and peripherally located on the inferior corneal endothelium. Clock-hour meridians extended from 4 to 7 o'clock, with the largest PPPCE lesion spanning 4.3 clock hours. Gonioscopy revealed distinct well-circumscribed brown-pigmented plaques adherent to the corneal endothelium with no extension beyond the trabecular meshwork. Ultrasound biomicroscopy and anterior segment ocular coherence tomography revealed the presence of hyperreflective lesions with no corneal stromal invasion, edema, or epitheliopathy. There were no synchronous anterior or posterior segment abnormalities. The PPPCE lesions have remained unchanged for a mean of 17 months (range, 8-34). Four healthy patients were noted to have PPPCE lesions. Although their etiology remains unknown, PPPCE behavior, morphology, and inferior corneal location suggest an origin from iris stromal melanocytes or iris pigment epithelium.

Intrinsic Lens Forming Potential of Mouse Lens Epithelial versus Newt Iris Pigment Epithelial Cells in Three-Dimensional Culture

Adult newts (Notophthalmus viridescens) are capable of complete lens regeneration that is mediated through dorsal iris pigment epithelial (IPE) cells transdifferentiation. In contrast, higher vertebrates such as mice demonstrate only limited lens regeneration in the presence of an intact lens capsule with remaining lens epithelial cells. To compare the intrinsic lens regeneration potential of newt IPE versus mouse lens epithelial cells (MLE), we have established a novel culture method that uses cell aggregation before culture in growth factor-reduced Matrigel. Dorsal newt IPE aggregates demonstrated complete lens formation within 1 to 2 weeks of Matrigel culture without basic fibroblast growth factor (bFGF) supplementation, including the establishment of a peripheral cuboidal epithelial cell layer, and the appearance of central lens fibers that were positive for αA-crystallin. In contrast, the lens-forming potential of MLE cell aggregates cultured in Matrigel was incomplete and resulted in the formation of defined-size lentoids with partial optical transparency. While the peripheral cell layers of MLE aggregates were nucleated, cells in the center of aggregates demonstrated a nonapoptotic nuclear loss over a time period of 3 weeks that was representative of lens fiber formation. Matrigel culture supplementation with bFGF resulted in higher transparent bigger-size MLE aggregates that demonstrated increased appearance of βB1-crystallin expression. Our study demonstrates that bFGF is not required for induction of newt IPE aggregate-dependent lens formation in Matrigel, while the addition of bFGF seems to be beneficial for the formation of MLE aggregate-derived lens-like structures. In conclusion, the three-dimensional aggregate culture of IPE and MLE in Matrigel allows to a higher extent than older models the indepth study of the intrinsic lens-forming potential and the corresponding identification of lentogenic factors.

Kyste vitréen partiellement pigmenté

Free-floating iris pigment epithelial cysts in the vitreous are very rare. We report the case of a partially pigmented cyst found on routine examination in the vitreous of a 51-year-old asymptomatic patient. Usually, non-pigmented cysts are derived from the hyaloid system. Pigmented cysts, however, are derived from the iris pigment epithelium. When they are not dislodged, these cysts can be confused with iris melanoma or primary stromal cysts. Treatment is usually unnecessary, unless they become symptomatic.

Morphology of the elygium and developing umbraculum in the eye of Amietia vertebralis tadpoles

The elygium is a darkly pigmented projection over the pupil of the tadpoles of certain species that live mostly at high altitudes. It has been suggested that this structure shades the retina, protecting it from high UV levels. In post-metamorphic individuals, the elygium is replaced by a structure known as an umbraculum. Confusion arose in the past from the inconsistent use of terminology when referring to these two structures. While they may serve the same function, these structures differ fundamentally in structure and origin. Our investigation of the ultrastructure of the eye in Amietia vertebralis tadpoles, using electron and light microscopy, revealed that the elygium consists of an accumulation of melanophores situated within the inner cornea, whereas the umbraculum is a dorsal extension of the iris pigment epithelium, analogous to the ventral pupillary nodule, which is present in most frog species. In A. vertebralis, the umbraculum starts to develop on the iris of older tadpoles (Gosner [1960] stage 37 Herpetologica 16:183-190), medial to the overlying elygium. A smaller, ventral elygium is also present in this species and is similar in structure to the dorsal elygium. The development of the elygium over a six-month period is also described.

Review of cystic and solid tumors of the iris

Iris tumors are broadly classified into cystic or solid lesions. The cystic lesions arise from iris pigment epithelium (IPE) or iris stroma. IPE cysts classically remain stable without need for intervention. Iris stromal cyst, especially those in newborns, usually requires therapy of aspiration, possibly with alcohol-induced sclerosis, or surgical resection. The solid tumors included melanocytic and nonmelanocytic lesions. The melanocytic iris tumors include freckle, nevus (including melanocytoma), Lisch nodule, and melanoma. Information from a tertiary referral center revealed that transformation of suspicious iris nevus to melanoma occurred in 4% by 10 years and 11% by 20 years. Risk factors for transformation of iris nevus to melanoma can be remembered using the ABCDEF guide as follows: A=age young (<40 years), B=blood (hyphema) in anterior chamber, C=clock hour of mass inferiorly, D=diffuse configuration, E=ectropion, F=feathery margins. The most powerful factors are diffuse growth pattern and hyphema. Tumor seeding into the anterior chamber angle and onto the iris stroma are also important. The nonmelanocytic iris tumors are relatively uncommon and included categories of choristomatous, vascular, fibrous, neural, myogenic, epithelial, xanthomatous, metastatic, lymphoid, leukemic, secondary, and non-neoplastic simulators. Overall, the most common diagnoses in a clinical series include nevus, IPE cyst, and melanoma. In summary, iris tumors comprise a wide spectrum including mostly iris nevus, IPE cyst, and iris melanoma. Risk factors estimating transformation of iris nevus to melanoma can be remembered by the ABCDEF guide.

Moxifloxacin and bilateral acute iris transillumination

Recent publications have alerted clinicians to a syndrome of uveitic transilluminating iris depigmentation associated with systemic fluoroquinolones and other antibiotics. Bilateral acute iris transillumination, which is associated with loss of the iris pigment epithelium and results in iris transillumination, differs from the previously described bilateral acute depigmentation of the iris, which is associated with atrophy of the iris stroma without transillumination. We present a case of fluoroquinolone-associated uveitis with anterior segment optical coherence tomography imaging to highlight some observations about this syndrome. We interpret pharmacokinetic data to help explain why oral, but not topical, moxifloxacin may cause fluoroquinolone-associated uveitis.

Pigment Dispersion Glaucoma Induced by the Chafing Effect of Intraocular Lens Haptics in Asian Eyes

ABSTRACTPurpose: To study the possible mechanism and treatment for pigment dispersion glaucoma (PDG) caused by single-piece acrylic (SPA) intraocular lens (IOL) ciliary sulcus fixation in Asian eyes.Materials and methods: Patients referred for PDG caused by SPA IOL ciliary sulcus fixation to our hospital from April 2005 to June 2011 were included. The patients’ general information, IOL type, interval between initial surgery and PDG occurrence, examination findings, antiglaucoma medicine regimen and surgical interventions were recorded.Results: In total, six eyes from five Chinese patients were included in this study. The intraocular pressure (IOP) increased 19–30 days after cataract surgery and was not satisfactorily controlled with antiglaucoma medication. Dense pigmentation was deposited on the IOLs and on the anterior chamber angle. IOL haptic chafing was noted on the rear iris surface. IOL repositioning in the capsular bag was performed in three eyes and was combined with trabeculectomy in two eyes with progressive glaucoma. An IOL exchange with three-piece IOL ciliary sulcus fixation was performed in the other three eyes. Scanning electron microscopy of the explanted IOLs demonstrated a rough edge on the IOL haptics.Conclusions: SPA IOLs were not suitable for ciliary sulcus fixation. The chafing effect of the IOL haptics on the posterior iris pigment epithelium could induce PDG in Asian eyes. IOLs should be positioned in the capsular bag or a three-piece IOL should be used instead.

Immunological homeostasis of the eye

Uveitis is a sight-threatening disease caused by autoimmune or infection-related immune responses. Studies in experimental autoimmune uveitis and in human diseases imply that activated CD4(+) T cells, Th1 and Th17 cells, play an effector role in ocular inflammation. The eye has a unique regional immune system to protect vision-related cells and tissues from these effector T cells. The immunological balance between the pathogenic CD4(+) T cells and regional immune system in the eye contributes to the maintenance of ocular homeostasis and good vision. Current studies have demonstrated that ocular parenchymal cells at the inner surface of the blood-ocular barrier, i.e. corneal endothelial (CE) cells, iris pigment epithelial (PE) cells, ciliary body PE cells, and retinal PE cells, contribute to the regional immune system of the eye. Murine ocular resident cells directly suppress activation of bystander T cells and production of inflammatory cytokines. The ocular resident cells possess distinct properties of immunoregulation that are related to disparate anatomical location. CE cells and iris PE cells, which are located at the anterior segment of the eye and face the aqueous humor, suppress activation of T cells via cell-to-cell contact mechanisms, whereas retinal PE cells suppress the activation of T cells via soluble factors. In addition to direct immune suppression, the ocular resident cells have another unique immunosuppressive property, the induction of CD25(+)Foxp3(+) Treg cells that also suppress the activation of bystander T cells. Iris PE cells convert CD8(+) T cells into Treg cells, while retinal PE cells convert CD4(+) T cells greatly and CD8(+) T cells moderately into Treg cells. CE cells also convert both CD4(+) T cells and CD8(+) T cells into Treg cells. The immunomodulation by ocular resident cells is mediated by various soluble or membrane-bound molecules that include TGF-β TSP-1, B7-2 (CD86), CTLA-2α, PD-L1 (B7-H1), galectin 1, pigment epithelial-derived factor PEDF), GIRTL, and retinoic acid. Human retinal PE cells also possess similar immune properties to induce Treg cells. Although there are many issues to be answered, human Treg cells induced by ocular resident cells such as retinal PE cells and related immunosuppressive molecules can be applied as immune therapy for refractive autoimmune uveitis in humans in the future.

Aquaporins 6-12 in the human eye

Aquaporins (AQPs) are widely expressed and have diverse distribution patterns in the eye. AQPs 0-5 have been localized at the cellular level in human eyes. We investigated the presence of the more recently discovered AQPs 6-12 in the human eye. RT-PCR was performed on fresh tissue from two human eyes divided into the cornea, corneal limbus, ciliary body and iris, lens, choroid, optic nerve, retina and sclera. Each structure was examined to detect the mRNA of AQPs 6-12. Twenty-one human eyes were examined using immunohistochemical and immunofluorescence techniques to determine the topographical localization of AQPs 6-12. mRNA transcripts of AQP7, AQP9 and AQP11 were found in the ciliary body, corneo-limbal tissue, optic nerve, retina and sclera. AQP9 and AQP11 mRNA was also detected in the choroid. No mRNA of AQP6, AQP8, AQP10 or AQP12 was detected. Anti-AQP7 immunolabelling was detected in the corneal epithelium, corneal endothelium, trabecular meshwork endothelium, ciliary epithelia, lens epithelium, the inner and outer limiting membrane of the retina, the retinal pigment epithelium and the capillary endothelium of all parts of the eye. AQP9 immunolabelling was detected in the nonpigmented ciliary epithelium and retinal ganglion cells. AQP11 immunolabelling was detected in the corneo-limbal epithelium, nonpigmented ciliary epithelium and inner limiting membrane of the retina. Selective expression of AQP7, AQP9 and AQP11 was found within various structures of the human eye. The detection of these aquaporins in the eye implies a role that may be related not only to water transport but also to the transport of glycerol, lactate and ammonia, with importance for metabolism, especially in the retina.

Bilateral primary iris pigment epithelial cysts

AbstractPurpose To report a patient who presented with bilateral primary iris pigment epithelial cysts.Methods Interventional case report.Results A 30‐year‐old lady with the diagnosis of bilateral primary cysts of the iris pigment epithelium was referred. Her father had been diagnosed with a uveal melanoma 13 years earlier. Two smaller circumferential midzonal iris pigment epithelial cysts and a larger inferonasal cyst located in the temporal area were observed in her right eye, and a similar but much larger cyst was observed in her left eye temporally between 1 o'clock and 6 o'clock meridians. Otherwise, the anterior and posterior segment as well as the intraocular pressure (16 mmHg) were normal. The visual acuity was 20/20 without correction, right eye, and 20/20 with a +0.75 sphere, left eye, with a shadow in the field. For the decrease of vision in her left eye the cyst was treated with neodymium‐doped yttrium aluminum garnet (Nd:YAG) laser cystotomy without any ocular tissue damage using the Abraham iridectomy lens and a 1.0 mJ single pulse. Cystotomy resulted in immediate collapse of the cyst with no change in intraocular pressure.Conclusion Laser cystotomy yielded a favorable result. Generally, these cysts which most frequently occur in young females do not need any treatment, but transpupillary laser cystotomy is an alternative to a conservative regimen if iris the cyst is symptomatic.

Gene Expression Profiles and Retinal Potential of Stem/Progenitor Cells Derived from Human Iris and Ciliary Pigment Epithelium

The aim of our study was to isolate and characterize the properties of neurospheres and differentiated cellular progeny derived from iris and ciliary pigment epithelial (IPE and CPE) cells of human cadaveric eyes. In this study we investigated the gene expression profiles of the stem/progenitor cells and the differentiated progeny derived from IPE and CPE cells, as the changes underlying differentiation of the stem/progenitor derived from the IPE and CPE cells from human cadaveric eye are essentially unknown. The IPE and CPE cells from human cadaver eyes were cultured in the presence of mitogens to generate neurospheres (NS) and the growth characteristics were evaluated. The Neurospheres (NS) were plated under conditions inducing differentiation and their potential was analyzed by RT-PCR, immunocytochemistry, calcium imaging studies and microarray studies to measure the changes involved in the process of differentiation. The IPE and CPE cells can generate NS containing progenitor cells in the presence of mitogens and were capable of producing different retinal cell types as demonstrated by RT-PCR and immunocytochemistry. The cluster analyses of the differentially expressed genes show the dynamic changes that occur during the course of IPE and CPE neurospheres differentiating into retinal progeny. The study gives clues towards the changes that occur during differentiation from NS into retinal progeny. In the present study we have demonstrated the expansion and maintenance of SCs from IPE and CPE of cadaveric eyes. These cells maintain their self-renewal properties and the ability to differentiate along retinal cell lineages and hence could be a practical source of donor cells for ex-vivo stem cell therapy during retinal degeneration.

Derivation of Human Differential Photoreceptor-like Cells from the Iris by Defined Combinations of CRX, RX and NEUROD

Examples of direct differentiation by defined transcription factors have been provided for beta-cells, cardiomyocytes and neurons. In the human visual system, there are four kinds of photoreceptors in the retina. Neural retina and iris-pigmented epithelium (IPE) share a common developmental origin, leading us to test whether human iris cells could differentiate to retinal neurons. We here define the transcription factor combinations that can determine human photoreceptor cell fate. Expression of rhodopsin, blue opsin and green/red opsin in induced photoreceptor cells were dependent on combinations of transcription factors: A combination of CRX and NEUROD induced rhodopsin and blue opsin, but did not induce green opsin; a combination of CRX and RX induced blue opsin and green/red opsin, but did not induce rhodopsin. Phototransduction-related genes as well as opsin genes were up-regulated in those cells. Functional analysis; i.e. patch clamp recordings, clearly revealed that generated photoreceptor cells, induced by CRX, RX and NEUROD, responded to light. The response was an inward current instead of the typical outward current. These data suggest that photosensitive photoreceptor cells can be generated by combinations of transcription factors. The combination of CRX and RX generate immature photoreceptors: and additional NEUROD promotes maturation. These findings contribute substantially to a major advance toward eventual cell-based therapy for retinal degenerative diseases.

Four Subunits (αβγδ) of the Epithelial Sodium Channel (ENaC) Are Expressed in the Human Eye in Various Locations

The epithelial sodium channel (ENaC) is typically expressed in sodium-absorbing epithelia. Several reports suggest that ENaC is also expressed in ocular tissues and may play a role in aqueous humor secretion and glaucoma. However, the precise localization of ENaC in the human eye is still unclear. Here, the authors studied ENaC expression in 12 normal human donor eyes and in six eyes of patients with glaucoma. Quantitative real-time PCR was used to investigate the expression of α-, β-, γ-, and δ-ENaC transcripts in ocular tissues. In addition, the authors performed immunohistochemical studies using recently generated antibodies against human β- and γ-ENaC. At the mRNA level, all four ENaC subunits were found to be expressed in a wide range of ocular tissues from normal and glaucomatous human eyes, with the cornea, ciliary body, iris, and retina showing the highest expression levels. At the protein level, β- and γ-ENaC subunits showed distinct distribution patterns and could be immunolocalized primarily to the cell membranes of epithelial cells of the cornea and to the conjunctiva, iris, ciliary body, lens, and retinal pigment epithelium but also to vascular endothelial cells, smooth muscle cells, stromal cells, and retinal neurons. The authors found no altered mRNA level of any subunit in glaucomatous eyes. All four ENaC subunits (αβγδ) are expressed in the normal human eye, with distinct localization of subunits possibly reflecting different functional states of the channel. The (patho-)physiological roles of ENaC in the various localizations in the eye remain to be determined.

Ophthalmic transplantology: Posterior segment of the eye – Part II

SummaryBackgroundTransplants of the retina are among the new strategies being used in the treatment of genetic and degenerative macular diseases. Moreover, various cell cultures are being tested to treat retinal disorders.Material/MethodsLiterature dated from 2004 to 2011 was comprehensively examined via Medline and PubMed searches for the following terms: auto-, homo-, heterologous transplantation, retina, stem cells, cultivated cells.ResultsTissue and cell therapy of retinal diseases are reviewed, including full-thickness retina/retinal pigment epithelium (RPE)/choroid graft; full and partial thickness RPE/choroid complex grafts; RPE/Bruch membrane complex graft; and RPE, iris pigment epithelium and stem cell grafts. Recommendations for transplants, as well as the benefits and weaknesses of specific techniques in retina transplants, are discussed.ConclusionsAuto- and allogenic transplants of a full or partial thickness retina/RPE/Bruch membrane/choroid complex represent an alternative treatment offered to patients with some macular diseases. Stem cell transplantation to reconstruct and regenerate the macula requires further biomolecular and animal research studies.

Clinical and Pathologic Characteristics of Biopsy-Proven Iris Melanoma

To collaborate with multiple centers to identify representative epidemiological, clinical, and pathologic characteristics of melanoma of the iris. This international, multicenter, Internet-assisted study in ophthalmic oncology demonstrates the collaboration among eye cancer specialists to stage and describe the clinical and pathologic characteristics of biopsy-proven melanoma of the iris. A computer program was created to allow for Internet-assisted multicenter, privacy-protected, online data entry. Eight eye cancer centers in 6 countries performed retrospective chart reviews. Statistical analysis included patient and tumor characteristics, ocular and angle abnormalities, management, histopathology, and outcomes. A total of 131 patients with iris melanoma (mean age, 64 years [range, 20-100 years]) were found to have blue-gray (62.2%), green-hazel (29.1%), or brown (8.7%) irides. Iris melanoma color was brown (65.6%), amelanotic (9.9%), and multicolored (6.9%). A mean of 2.5 clock hours of iris was visibly involved with melanoma, typically centered at the 6-o'clock meridian. Presentations included iritis, glaucoma, hyphema, and sector cataract. High-frequency ultrasonography revealed a largest mean tumor diameter of 4.9 mm, a mean maximum tumor thickness of 1.9 mm, angle blunting (52%), iris root disinsertion (9%), and posterior iris pigment epithelium displacement (9%). Using the American Joint Commission on Cancer-International Union Against Cancer classification, we identified 56% of tumors as T1, 34% of tumors as T2, 2% of tumors as T3, and 1% of tumors as T4. Histopathologic grades were G1-spindle (54%), G2-mixed (28%), G3-epithelioid (5%), and undetermined (13%) cell types. Primary treatment involved radiation (26%) and surgery (64%). Kaplan-Meier analysis found a 10.7% risk of metastatic melanoma at 5 years. Iris melanomas were most likely to be brown and found in the inferior quadrants of patients with light irides. Typically small and unifocal, melanomas are commonly associated with angle blunting and spindle cell histopathology. This multicenter, Internet-based, international study successfully pooled data and extracted information on biopsy-proven melanoma of the iris.

This issue of Acta, printed and electronic

The cover illustration shows a painting of Allvar Gullstrand painted in 1915, 4 years after he received the Nobel Prize for medicine. This issue is dedicated to the centennial of Allvar Gullstrand’s Nobel Prize. He is the only ophthalmologist ever to receive this prestigious price. Stefan Seregard writes an editorial commemorating this event. This is followed by an historical article by Ehinger and Grzybowski on the life and times of Allvar Gullstrand. Yilmaz et al. in USA, Spain and Ireland review the use of intravitreal bevacizumab for diabetic macular oedema. This is an extensive review of the literature for this new and important treatment modality. Lundström et al. in Sweden and Australia found the Catquest questionnaire useful for measuring self-assessed visual function before and after cataract surgery. Mönestam and Behndig found that light scattering and glistening in intraocular lenses does not affect visual acuity. Gazieva et al. in Denmark performed LASIK with two types of laser systems, both which effectively reduce high degrees of myopia with reasonable but slightly different predictability. Rijneveld et al. in the Netherlands found that emergency corneal grafts fail mostly due to host factors, not the quality of the donor tissue. Reinshagen et al. in Switzerland and Germany used mesenchymal stem cell in rabbits to treat total limbal stem cell deficiency. Heijl et al. in Sweden and USA report that intraocular pressure reduction with drug treatment depends on the baseline IOP level and suggest that the baseline IOP level should be documented when reporting treatment effect on intraocular pressure. Larsson et al. in Sweden used the Heidelberg retina tomography system to evaluate optic nerve heads in children. Lin et al. in Taiwan describe lacrimal canaliculitis in a series of patients. Mehlsen et al. in Denmark found that a calcium channel blocker and an angiotensin converting enzyme inhibitor did not influence retinal autoregulation in diabetic patients. Kook et al. in Germany found that intravitreal bevacizumab and/or triamcinolone do not provide long-term improvement for diabetic macular oedema. Kofoed et al. in Copenhagen found that hyperbaric oxygen exposure influenced electrophysiological components related to bipolar in Müller cells. It did not influence retinal thickness. Holton et al. in Denmark examined the influence of light source on contrast sensitivity in patients with AMD. They found that full spectral radiance incandescent light sources seem optimal. Available on http://www.actaophthalmologica.com Stalmans and a large international group review extensively the use of colour Doppler imaging in ocular blood flow research. Founti et al. in Greece and USA found good reproducibility between technicians in imaging retrobulbar blood flow in healthy volunteers. Frøen et al. in Norway and Hungary found that cells from the iris pigment epithelium have limited capabilities as retinal stem cells. Andjelić et al. in Slovenia found that lens capsule contraction with changing in calcium levels or mechanical stimulus. Sieving in USA explains Medline indexing and keywords. Bull in Bergen proposes that fireworks should be banned to reduce eye injuries. Basit et al. in Trondheim describe a case of Wernicke’s encephalopathy in a young boy. Russo et al. in Liverpool found scleral calcification in a case of recurrent melanoma after brachytherapy. Rama et al. in Italy report severe keratitis following corneal cross-linking for keratoconus. Jonas and Jonas in Germany compare peripapillary scleral thickness in glaucoma patients and normal subjects. Lim and An in Korea report good results after epiretinal membrane removal. Kernt et al. in Germany had good experiences with focal and panretinal photocoagulation with a navigated laser. Fielden et al. in Canada describe a cluster of cases with intraocular inflammation following bevacizumab injection. Bloch et al. in Denmark and Egypt describe neovascular membrane contraction and retinal pigment epithelial rupture following verteporfin and bevacizumab treatment. Caramoy et al. in Germany found recurrent choroidal neovascular membrane after autologous RPE transplantation. I wish all readers a Merry Christmas and a Happy New Year and hope that they enjoy reading ACTA during the holidays.