PURPOSE. The purpose of this study was to develop a porcine model of rhegmatogenous retinal detachment (RRD) associated with posterior vitreous detachment (PVD) that can be used to evaluate surgical repair with small-gauge pars plana vitrectomy (PPV) utilizing contemporary methods. METHODS. A total of 11 eyes from 7 Yucatan minipigs underwent 23-gauge PPV, triamcinolone-assisted PVD induction, retinal detachment creation using subretinal injection of balanced salt solution (BSS), and creation of an iatrogenic retinal break. In seven eyes, the induced RRD was repaired with fluid-air exchange, laser photocoagulation, and silicone oil tamponade. Another four eyes were planned, un-reattached RRD controls, and the remaining three eyes were used as non-surgical controls. Animals were examined 1 month postoperatively with indirect ophthalmoscopy, fundus photography, optical coherence tomography (OCT), and full-field electroretinography (ERG). Animals were euthanized and processed for histopathologic analysis. RESULTS. At 1 month postoperatively, all seven surgically repaired eyes remained attached under oil, with no observed complications. Two of four unrepaired control eyes demonstrated persistent and progressive retinal detachments, whereas the other two unrepaired eyes had spontaneously reattached retinas with variably sized retinal folds. CONCLUSIONS. Current conventional vitrectomy surgery methods can be used to create a pig model of RRD and successful repair with PPV, laser retinopexy, and silicone oil tamponade. This model may be useful for investigations regarding cellular and molecular changes associated with RRD pathogenesis and response to repair, as well as for comparing new surgical instrumentation, techniques, and tamponade agents for retinal reattachment.

ABSTRACT Age-related macular degeneration (AMD) is a common, complex disease affecting older individuals that can lead to severe vision loss. It is characterized by early anatomical changes in the retina, retinal pigment epithelium (RPE), and choroid, especially in the central (macular) region. AMD can progress to severe atrophy and/or pathologic angiogenesis that leads to visual decline. Over 30 genetic loci have been identified as contributing to AMD risk; however, the mechanisms by which genetic variants affect pathology has not been thoroughly explored. In this report we examined single-nucleus gene expression in the retina, RPE and choroid of 88 individuals categorized by AMD stage, as well as 36 previously published samples. Genotyping was performed on 1.8 million SNPs, with additional SNPs imputed, on each donor to identify expression quantitative trait loci (eQTLs). We found that two AMD-risk loci (PILRB and ARMS2/HTRA1) affected the expression of PILRB and HTRA1 , respectively. The risk allele of PILRB was associated with increased PILRB RNA in cones, fibroblasts, choroidal resident macrophages, and RPE, whereas the HTRA1 risk locus was associated with decreased HTRA1 RNA in the RPE. We also identified an age-related decrease in complement inhibitors in the choriocapillaris, a tissue susceptible to complement mediated damage in AMD. We have made the eQTL and gene expression data fully available on the web resource Spectacle for rapid and interactive data access.

Age-related macular degeneration (AMD) is a common, complex disease affecting older individuals that can lead to severe vision loss. It is characterized by early anatomical changes in the retina, retinal pigment epithelium (RPE), and choroid, especially in the central (macular) region. AMD can progress to severe atrophy and/or pathologic angiogenesis that leads to visual decline. Over 30 genetic loci have been identified as contributing to AMD risk; however, the mechanisms by which genetic variants affect pathology has not been thoroughly explored. In this report we examined single-nucleus gene expression in the retina, RPE and choroid of 88 individuals categorized by AMD stage, as well as 37 previously published samples. Genotyping was performed on 1.8 million SNPs, with additional SNPs imputed, on each donor to identify expression quantitative trait loci (eQTLs). We found that two AMD-risk loci (PILRB and ARMS2/HTRA1) affected the expression of PILRB and HTRA1, respectively. The risk allele of PILRB was associated with increased PILRB RNA in cones, fibroblasts, choroidal macrophages, and RPE, whereas the HTRA1 risk locus was associated with decreased HTRA1 RNA in the RPE. We also identified an age-related decrease in complement inhibitors in the choriocapillaris, a tissue susceptible to complement mediated damage in AMD.

OBJECTIVE:To (1) determine the expression and distribution of all PDE4 isozymes (A-D) along the anterior urethra, (2) culture fibroblasts and epithelial cells from healthy and strictured urethras, (3) investigate an in vitro model of anterior urethral stricture disease (aUSD), and (4) assess the therapeutic potential of phosphodiesterase-4 (PDE4) inhibitors and testosterone compared to paclitaxel. METHODS:The presence and relative abundance of PDE4 isozymes (A-D) was confirmed using immunohistochemistry on 5 male cadaveric urethras. Human urethral fibroblasts (FBs) were cultured from healthy control urethras of patients undergoing vaginoplasty (n = 3) and from idiopathic bulbar urethral strictures (L2S1E2) of patients undergoing urethroplasty (n = 3). Epithelial cells (ECs) were cultured from a healthy control urethra and two urethral strictures. To investigate a model of aUSD, Control FBs were stimulated with TGFβ1 and compared to Stricture FBs on assays of cell proliferation and expression of genes relevant to aUSD pathophysiology. To test therapeutics, Stricture FBs were treated with the PDE4 inhibitor, roflumilast, testosterone (T), or paclitaxel and compared to Control FBs on the previously mentioned assays and cell viability. RESULTS:PDE4-A, B, and D were detected along the urethra and did not differ between regions. TGFβ1 altered proliferation and gene expression in a dose-dependent manner. Roflumilast and T preserved cell viability and proliferation and decreased expression of genes positively associated with aUSD. CONCLUSION:Urethral FBs and ECs can be cultured from healthy and strictured surgical specimens, enabling in vitro research. PDE4 inhibitors and T may be non-cytotoxic alternatives or additions to paclitaxel for aUSD.

Purpose:Loss of the choroid is an important pathophysiological step in retinal diseases ranging from age-related macular degeneration (AMD) to choroideremia. However, current models of choroidal injury, such as laser photocoagulation-induced injury, induce acute tissue damage that does not parallel the gradual loss seen in most retinal degenerations. As such, there remains a need for models of targeted choroidal injury to study mechanisms of disease and develop potential treatments. Methods:We report a targeted choroidal injury model using bioconjugated saporins (immunotoxins) against cluster of differentiation (CD) domains CD38 and CD105. To induce injury, 10 µL of bioconjugate solution or control (phosphate-buffered saline) was delivered via suprachoroidal injection in wild-type Sprague-Dawley (SD) and Sprague-Dawley Rag2/Il2rg (SRG; double-knockout) rats. The extent and severity of choroidal injury were compared with animals treated with sodium iodate administered via tail vein injections at 1, 2, and 3 weeks post-treatment using clinical imaging and immunohistochemistry. Results:Choroidal injury induced by either anti-CD38 or anti-CD105 immunotoxin was targeted to the choroid and localized to the sector of the injection, unlike global destruction induced by sodium iodate. Immunotoxin-induced vascular damage remained constant over 3 weeks, without choroidal neovascularization seen, whereas sodium iodate caused progressive and severe injury of the choroid and overlying retina. Conclusions:Suprachoroidal injection of anti-CD38 and anti-CD105 immunotoxins can induce localized and durable choroidal injury in both wild-type and immunosuppressed rats. Translational Relevance:Immunotoxin-based models of targeted choroidal injury may be useful for understanding pathophysiologic mechanisms and developing therapies in conditions involving choroidal cell death.

Purpose:Compare the effect of MEK inhibition on iPSC-derived retinal pigmental epithelial (RPE) cells generated from a patient who developed MEK inhibitor-Associated Retinopathy (MEKAR) versus a patient who did not develop retinopathy. Design:Case-control. Subjects:Two female patients with Neurofibromatosis Type 1 who were treated with MEK inhibitors. One patient developed MEKAR, the other did not. Methods:RPE were generated from human induced pluripotent stem cells (hiPSCs) from these two patients. These hiPSC-derived RPE were treated with selumetinib for 10 days. Main Outcome Measures:Phagocytic activity and changes in gene expression. Results:As previously reported, there was a significant increase in internalized rhodopsin in phagocytosis assays, yet this was only found in hiPSC-derived RPE from the patient who developed MEKAR. Selumetinib decreased expression of genes related to fluid transport and cell volume, including aquaporins and solute transporters. At baseline, cells from the patients without MEKAR had higher expression of these genes. Interestingly, selumetinib-induced changes in gene expression only reached statistical significance in cells from the patient who did not develop MEKAR, suggesting these changes may be a compensatory protective mechanism. Patients susceptible to forming MEKAR may have increased phagocytosis without a compensatory change in expression of genes related to fluid flux, thereby inhibiting their ability to transport fluid out of the subretinal space. Conclusions:MEK inhibitor-Associated Retinopathy may only affect susceptible patients whose retinal pigment epithelium cannot sufficiently regulate expression of genes related to fluid transport and cell volume, altering the ability of these cells to properly function.

PURPOSE:Autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV) is a rare inherited retinal disease caused by mutations in CAPN5. We report clinicopathologic and histologic findings from donor eyes representing multiple stages of ADNIV, including early-stage disease, and evaluate calpain-5 (CAPN5) expression and localization in affected tissue. METHODS:Histopathologic staining and immunofluorescence were performed on eyes from three patients with genetically confirmed ADNIV (stages II, IV, and V). Labeling targeted glial, immune, and vascular markers, as well as CAPN5 distribution. Western blotting of aqueous- and detergent-soluble fractions was performed on retinal and RPE/choroid tissue from the stage II donor and an age- and sex-matched control. Clinical history from the stage IV donor was reviewed. RESULTS:All three ADNIV eyes in this series demonstrated lymphocytic infiltration predominantly confined to the choroid. The stage II eye showed preserved retinal organization with early Müller cell gliosis and microglial activation. Later stages exhibited neuroretinal disorganization and fibrovascular encapsulation. RPE preservation was noted in all 3 eyes. CAPN5 was expressed throughout retinal and choroidal tissues. Western blot and fractionation analysis of the stage II eye showed no difference in CAPN5 abundance or distribution compared with control tissue. CONCLUSION:These findings support a disease process characterized by early choroidal inflammation and progressive retinal degeneration in ADNIV. Stable CAPN5 localization in early disease suggests that pathogenic effects may arise from altered mutant protease activity rather than from changes in protein abundance or localization. Recognition of early inflammatory changes may inform future diagnostic and therapeutic approaches in this rare condition.

Age-related macular degeneration is a common ocular disease that causes vision loss in the elderly, with a complex set of risk factors and proposed mechanisms of pathogenesis. A powerful method for investigating changes in disease is metabolomics, by which small molecules can be identified and quantified simultaneously. We report here the metabolic analysis of human RPE-choroid tissue in aging and macular degeneration (AMD), as well as comparisons of human macular and extramacular RPE-choroid and neural retina. Levels of 215 metabolites were determined in young donors, AMD donors (early/intermediate, geographic atrophy, and neovascularization) and age-matched controls. The largest number of metabolite differences were observed between young and healthy aged controls, as opposed to between aged controls and any stage of AMD. Two notable metabolites found to be increased in aging choroids are trimethylamine N-oxide and uric acid, both of which were significant after Bonferroni correction. A mouse endothelial cell line treated with a high concentration of uric acid exhibited reduced migration in a wound closure assay. This study provides initial insights into the metabolome of human choroids in varying states of age and macular degeneration, as well as functional implications of these changes in the aging choroid.

BACKGROUND:Neurodegenerative conditions that affect the retina are currently the leading cause of incurable blindness in the developed world. Although gene and drug therapies are being developed to slow disease progression in some cases, restorative cell replacement approaches are needed for patients with significant vision impairment due to retinal degeneration. While a variety of different cell types have been evaluated in the context of retinal cell replacement, induced pluripotent stem cells (iPSCs), which can be generated and delivered as an autologous therapeutic, are in many ways the most attractive donor cell source currently available. Like embryonic stem cells, iPSCs must be differentiated into the target therapeutic cell type prior to transplantation. For instance, for patients with retinitis pigmentosa who have primary photoreceptor cell disease, photoreceptor cell derivation and enrichment are required prior to transplantation. Although other effective retinal differentiation protocols exist, they are often not fully compatible with clinical manufacturing. METHODS:Patient-derived iPSCs were generated via Sendai viral vector mediated reprogramming of dermal fibroblasts. Retinal organoids were generated using a stepwise 3D differentiation protocol testing different current good manufacturing practice (cGMP) compliant reagents and oxygen tension in a cGMP compliant Biospherix cell culture isolator. Organoids were dissociated with papain and photoreceptor precursor cells were transplanted into immune suppressed Pde6b-null rats. Human donor cell survival, cellular identity, and synaptic integration were assessed at 3- and 30-days post-injection. RESULTS:We developed of a xeno-free 3D retinal differentiation protocol based on the most robust adherent/non-adherent 3D differentiation strategies published to date. In addition, we demonstrate that while iPSC reprogramming efficiency is enhanced under reduced oxygen tension (i.e., 5%), efficient embryoid body and subsequent retinal organoid production require standard oxygen levels (i.e., 20%). Finally, we show that photoreceptor precursor cells obtained from 3D retinal organoids derived using the developed protocol under cGMP survive in the subretinal space of dystrophic Pde6b-null rats for 30 days post-transplantation and form new synaptic connections with host bipolar neurons. Importantly, synaptic connectivity between transplanted photoreceptor cells and host bipolar neurons appeared to have a positive trophic effect. CONCLUSIONS:In this study, we report development of a xeno-free, cGMP compliant iPSC-3D retinal differentiation protocol for production of transplantable photoreceptor precursor cells.

Age-related macular degeneration is a leading cause of central vision loss in the elderly. Early hallmarks of the disease include basal laminar deposit and choriocapillaris degeneration. The location and composition of sialoglycoconjugates in healthy and diseased choroid and disease-related lesions have not been thoroughly examined. This study utilized lectins to examine sialoglycoconjugates in human tissue, specifically Sambucus nigra /Elderberry Bark Lectin (EBL) and Maackia amurensis lectin II (MAL-II), to examine α-2,6 and α-2,3 sialic acids, respectively. EBL and MAL-II both label the choroid and basal laminar deposit, with slightly different patterns. Whereas MAL-II predominantly labels the choriocapillaris endothelium, EBL also labels Bruch’s membrane and extracellular domains surrounding the vasculature (intercapillary pillars). EBL labeling overlaps with the distribution of complement factor H to a greater extent than MAL-II. After treatment with neuraminidase to remove terminal sialic acids, a battery of lectins was applied to sections of choroids. Lectins that recognize β-galactose, N-acetyllactosamine, galactose (β-1,3) N-acetylgalactosamine, and α - or β-N-acetylgalactosamine showed increased reactivity, including increased labeling of glycans in basal laminar deposits. This study provides insight into the location and partial identities of sialoglycoconjugates in the human choroid, with possible implications for the pathogenesis of macular degeneration. ### Competing Interest Statement The authors have declared no competing interest. NIH, , EY-024605, EY-033308, EY-025580, GM145441

In retinal diseases such as age-related macular degeneration (AMD) and choroideremia, a key pathophysiologic step is loss of endothelial cells of the choriocapillaris. Repopulation of choroidal vasculature early in the disease process may halt disease progression. Prior studies have shown that injection of donor cells in suspension results in significant cellular efflux and poor cell survival. As such, the goal of this study was to develop a hydrogel system designed to support choroidal endothelial cell transplantation. A library of hydrogels was synthesized using laminin (i.e., LN111, LN121, and LN421), carboxy methyl chitosan, and oxidized dextran via reversible Schiff base chemistry. Each of the developed self-healing hydrogels was readily injectable into the suprachoroidal space, with ideal gelation, mechanical, and degradation properties. While all hydrogels were found to be compatible with choroidal endothelial cell survival in vitro, only LN111 and LN121 gels were well-tolerated in vivo. To determine if hydrogel mediated cell delivery enhances donor cell retention and survival in vivo, iPSC-derived choroidal endothelial cell laden hydrogels were injected into the suprachoroidal space of an immunocompromised choroidal cell injury rat model. Significantly more donor cells were retained and survived in eyes that received cell laden hydrogels versus contralateral hydrogel free controls. Furthermore, donor cells positive for human nuclear antigen were identified in the choroid of hydrogel eyes only. These findings pave the way for future cell replacement studies in large animal models of choroidal cell dropout focused on evaluating functional integration of donor cells within decellularized vascular tubes. STATEMENT OF SIGNIFICANCE: Age related macular degeneration (AMD) is a leading cause of untreatable blindness in the industrial world. A key pathologic step in AMD is loss of the choriocapillaris endothelial cells, which provide vascular support to the overlying retina. Choroidal cell replacement early in disease may prevent retinal cell death and subsequent vision loss. In this study, we present a strategy for repopulating the choriocapillaris using choroidal endothelial cell laden hydrogels. Specifically, we demonstrate the synthesis and characterization of 3 different laminin-based hydrogel systems. LN111 and LN121 hydrogels were found to have excellent biocompatibility both in vitro and in vivo. Hydrogel mediated delivery of iPSC-derived choroidal endothelial cells enhanced donor cell retention and survival, paving the way for functional large animal studies.

Correct identification of the molecular consequences of pathogenic genetic variants is essential to the development of allele-specific therapies. However, such molecular effects may remain ambiguous following genetic sequence analysis alone. Here, we identify exonic codon-altering variants that are also predicted to disrupt normal RNA splicing in the context of inherited retinal disease. NR2E3 c.932G>A (p.Arg311Gln) is a variant commonly associated with enhanced S cone syndrome. Previous studies using mutagenized cDNA constructs have shown that the arginine to glutamine substitution at position 311 of NR2E3 does not meaningfully diminish function of the rod-specific transcription factor. Using retinal organoids, we explored the molecular consequences of NR2E3 c.932G>A when expressed endogenously during human rod photoreceptor cell development. Retinal organoids carrying the NR2E3 c.932G>A allele expressed a transcript containing a 186-nucleotide deletion of exon 6 within the ligand binding domain. This short transcript was not detected in control organoids or control human donor retina samples. A minigene containing exons 5 and 6 of NR2E3 showed sufficiency of the c.932G>A variant to cause the observed splicing defect. These results support the hypothesis that the pathogenic NR2E3 c.932G>A variant leads to photoreceptor disease by causing a splice defect and not through an amino acid substitution as previously supposed. They also explain the relatively mild effect of Arg311Gln on NR2E3 function in vitro. We also used in silico prediction tools to show that similar changes are likely to affect other inherited retinal disease variants in genes such as CEP290, ABCA4, and BEST1.

11-cis-Retinal is essential for light perception in mammalian photoreceptors (PRs), and aberrations in retinoid transformations cause severe retinal diseases. Understanding these processes is crucial for combating blinding diseases. The visual cycle, operating within PRs and the retinal pigment epithelium (RPE), regenerates 11-cis-retinal to sustain light sensitivity. Retinoids are also present in Müller glia (MG), hypothesized to supply 11-cis-retinol to cone PRs and retinal ganglion cells (RGCs). To trace retinoid movement through retinal cell types, we used cell-specific knockin of lecithin:retinol acyltransferase (LRAT), which converts retinols into stable retinyl esters (REs). Ectopic LRAT expression in murine PRs, MG, and RGCs resulted in RE synthesis, with REs differing in abundance and isomeric composition across cell types under genetic and light-based perturbations. PR inner segments showed high 11-cis-RE content, suggesting a constant 11-cis-retinoid supply for pigment regeneration. In MG expressing LRAT, all-trans-REs were detected, contrasting with 11-cis-REs in PRs. The MG-specific LRAT phenotype mirrored the RE-rich human neural retina, suggesting human MG may utilize LRAT to maintain retinoid reservoirs. Our findings reveal tightly controlled retinoid flux throughout the mammalian retina that supports sustained vision, expanding understanding of the visual cycle to combat retinal diseases.

Age-related macular degeneration is a leading cause of central vision loss in the elderly. Early hallmarks of the disease include basal laminar deposit beneath the retinal pigment epithelium (RPE) and choriocapillaris degeneration. We utilized sialic acid binding lectins Sambucus nigra/Elderberry Bark Lectin (EBL) and Maackia amurensis lectin II (MAL-II), to assess the localization of ɑ-2,6 and ɑ-2,3 sialic acids, respectively, in human macular retina, RPE, basal laminar deposits, and choroid. Photoreceptor carbohydrate epitopes differ based on retinal topography, with MAL-II recognizing foveal (but not extrafoveal) cones. Both MAL-II and EBL react with apical RPE, and both bind basal laminar deposits. In the choroid, MAL-II predominantly labels the choriocapillaris endothelium, while EBL also shows robust labeling of Bruch's membrane and extracellular domains surrounding the microvasculature (intercapillary pillars). EBL labeling overlaps with the distribution of complement factor H to a greater extent than MAL-II. After treatment with neuraminidase to remove terminal sialic acids, a battery of lectins was applied to sections of choroids. Lectins that recognize β-galactose, N-acetyllactosamine, galactose (β-1,3) N-acetylgalactosamine, and ɑ- or β-N-acetylgalactosamine showed increased reactivity, indicating the presence of abundant sialoglycans in basal laminar deposits. This study provides insight into the location and partial identities of sialoglycoconjugates in the human choroid, with possible implications for understanding the pathogenesis of macular degeneration.

Autologous photoreceptor cell replacement is one of the most promising strategies currently being developed for the treatment of patients with inherited retinal degenerative blindness. Induced pluripotent stem cell-derived (iPSC-derived) retinal organoids, which faithfully recapitulate the structure of the neural retina, are an ideal source of transplantable photoreceptors required for these therapies. However, retinal organoids contain other retinal cell types, including bipolar, horizontal, and amacrine cells, which are unneeded and may reduce the potency of the final therapeutic product. Therefore, approaches for isolating fate-committed photoreceptor cells from dissociated retinal organoids are desirable. In this work, we present partial dissociation, a technique that leverages the high level of organization found in retinal organoids to enable selective enrichment of photoreceptor cells without the use of specialized equipment or reagents such as antibody labels. We demonstrate up to 90% photoreceptor cell purity by simply selecting cell fractions liberated from retinal organoids during enzymatic digestion in the absence of mechanical dissociation. Since the presented approach relies on the use of standard plasticware and commercially available current good manufacturing practice-compliant reagents, we believe that it is ideal for use in the preparation of clinical photoreceptor cell replacement therapies.

Pharmacologic inhibitors of MEK are important anti-cancer drugs but can result in MEK inhibitor-Associated Retinopathy (MEKAR) in which vision is lost due to serous retinal detachments that form via an unknown mechanism. We hypothesized that the cause of this side effect is drug-induced dysfunction of retinal pigment epithelial (RPE) cells. To test this hypothesis, we used human induced pluripotent stem cell-derived RPE cells. We treated mature, hiPSC-derived RPE cells with selumetinib and measured impacts on RPE-specific function, structure, and gene expression. Selumetinib increases the ability of hiPSC-derived RPE to internalize bovine rod outer segments (1.9 vs 3.0, p=0.0024). It also decreases expression of aquaporin 1 during the first 10 days of treatment (2.7 vs 1.1, p=0.0015). It has no effect on the ability of hiPSC-derived RPE to maintain membrane integrity. Selumetinib alters gene expression of hiPSC-derived RPE, with significant changes in genes involved in transport of ions and small molecules regulating cell volume and lysosomal acidification. Selumetinib may lead to subretinal fluid accumulation by both increasing secretions into this space and decreasing outflow.

Choroidal neovascularization is a complication associated with retinal diseases such as age-related macular degeneration (AMD), a leading cause of vision loss in the developed world. Choroidal neovascular membrane (CNVM) refers to the abnormal growth of blood vessels in the retina which results in exudation and/or hemorrhage, leading to photoreceptor damage and vision loss. Currently first-line treatment for CNVM include intravitreal injections of vascular endothelial growth factor (VEGF)-binding antibodies that prevent the growth of these leaky blood vessels. Unfortunately, anti-VEGF drugs often require frequent injections, and prolonged VEGF inhibition has been associated with retinal atrophy and decreased long term effectiveness in some patients. This study presents the use of Acriflavine, a small molecule HIF1α inhibitor loaded polyurethane nanocapsules to treat CNVM in a rat model. Fourteen days following laser injury and intravitreal drug administration, CMVM size was significantly reduced in acriflavine nanocapsule and free acriflavine treated animals as compared to drug free controls. Moreover, acriflavine nanocapsules reduce CNVM incidence compared to drug free controls by approximately 25%. Among the different delivery routes tested, intravitreal delivery of acriflavine nanocapsules was found to be superior to subretinal and suprachoroidal delivery for reducing CNVM area without causing significant damage to the neural retina. This paper presents the synthesis, characterization and the effectiveness of the polyurethane based acriflavine delivery system in treating choroidal neovascularization.

In this review, we aim to provide a survey of hereditable tumor predisposition syndromes with a Mendelian inheritance pattern and ocular involvement. We focus our discussion on von Hippel-Lindau disease, neurofibromatosis type 1, NF2-related schwannomatosis, tuberous sclerosis complex, retinoblastoma, and the BAP1 tumor predisposition syndrome. For each of the six diseases, we discuss the clinical presentation and the molecular pathophysiology. We emphasize the genetics, current research models, and therapeutic developments. After reading each disease section, readers should possess an understanding of the clinical presentation, genetic causes and inheritance patterns, and current state of research in disease modeling and treatment.