In Vivo Assessment of Retinal Phenotypes in Axenfeld-Rieger Syndrome.

Purpose: Axenfeld-Rieger syndrome (ARS) is characterized by ocular anomalies including posterior embryotoxon, iridocorneal adhesions, corectopia/iris hypoplasia, and developmental glaucoma. Although anterior segment defects and glaucoma contribute to decreased visual acuity, the role of potential posterior segment abnormalities has not been explored. We used high-resolution retinal imaging to test the hypothesis that individuals with ARS have posterior segment pathology. Methods: Three individuals with FOXC1-ARS and 10 with PITX2-ARS completed slit-lamp and fundus photography, optical coherence tomography (OCT), OCT angiography, and adaptive optics scanning light ophthalmoscopy (AOSLO). Quantitative metrics were compared to previously published values for individuals with normal vision. Results: All individuals demonstrated typical anterior segment phenotypes. Average ganglion cell and inner plexiform layer thickness was lower in PITX2-ARS, consistent with the glaucoma history in this group. A novel phenotype of foveal hypoplasia was noted in 40% of individuals with PITX2-ARS (but none with FOXC1-ARS). Moreover, the depth and volume of the foveal pit were significantly lower in PITX2-ARS compared to normal controls, even excluding individuals with foveal hypoplasia. Analysis of known foveal hypoplasia genes failed to identify an alternative explanation. Foveal cone density was decreased in one individual with foveal hypoplasia and normal in six without foveal hypoplasia. Two individuals (one from each group) demonstrated non-foveal retinal irregularities with regions of photoreceptor anomalies on OCT and AOSLO. Conclusions: These findings implicate PITX2 in the development of the posterior segment, particularly the fovea, in humans. The identified posterior segment phenotypes may contribute to visual acuity deficits in individuals with PITX2-ARS.

Quantitative Foveal Structural Metrics as Predictors of Visual Acuity in Human Albinism.

Purpose: To assess the degree to which quantitative foveal structural measurements account for variation in best-corrected visual acuity (BCVA) in human albinism. Methods: BCVA was measured and spectral domain optical coherence tomography (SD-OCT) images were acquired for 74 individuals with albinism. Categorical foveal hypoplasia grades were assessed using the Leicester Grading System for Foveal Hypoplasia. Foveal anatomical specialization (foveal versus parafoveal value) was quantified for inner retinal layer (IRL) thickness, outer segment (OS) length, and outer nuclear layer (ONL) thickness. These metrics, participant sex, and age were used to build a multiple linear regression of BCVA. This combined linear model's predictive properties were compared to those of categorical foveal hypoplasia grading. Results: The cohort included three participants with type 1a foveal hypoplasia, 23 participants with type 1b, 33 with type 2, ten with type 3, and five with type 4. BCVA ranged from 0.08 to 1.00 logMAR (mean ± SD: 0.53 ± 0.21). IRL ratio, OS ratio, and ONL ratio were measured in all participants and decreased with increasing severity of foveal hypoplasia. The best-fit combined linear model included all three quantitative metrics and participant age expressed as a binary variable (divided into 0-18 years and 19 years or older; adjusted R2 = 0.500). This model predicted BCVA more accurately than a categorical foveal hypoplasia model (adjusted R2 = 0.352). Conclusions: A quantitative model of foveal specialization accounts for more variance in BCVA in albinism than categorical foveal hypoplasia grading. Other factors, such as optical aberrations and eye movements, may account for the remaining unexplained variance.

Axenfeld-Rieger syndrome: more than meets the eye.

BACKGROUND: Axenfeld-Rieger syndrome (ARS) is characterised by typical anterior segment anomalies, with or without systemic features. The discovery of causative genes identified ARS subtypes with distinct phenotypes, but our understanding is incomplete, complicated by the rarity of the condition. METHODS: Genetic and phenotypic characterisation of the largest reported ARS cohort through comprehensive genetic and clinical data analyses. RESULTS: 128 individuals with causative variants in PITX2 or FOXC1, including 81 new cases, were investigated. Ocular anomalies showed significant overlap but with broader variability and earlier onset of glaucoma for FOXC1-related ARS. Systemic anomalies were seen in all individuals with PITX2-related ARS and the majority of those with FOXC1-related ARS. PITX2-related ARS demonstrated typical umbilical anomalies and dental microdontia/hypodontia/oligodontia, along with a novel high rate of Meckel diverticulum. FOXC1-related ARS exhibited characteristic hearing loss and congenital heart defects as well as previously unrecognised phenotypes of dental enamel hypoplasia and/or crowding, a range of skeletal and joint anomalies, hypotonia/early delay and feeding disorders with structural oesophageal anomalies in some. Brain imaging revealed highly penetrant white matter hyperintensities, colpocephaly/ventriculomegaly and frequent arachnoid cysts. The expanded phenotype of FOXC1-related ARS identified here was found to fully overlap features of De Hauwere syndrome. The results were used to generate gene-specific management plans for the two types of ARS. CONCLUSION: Since clinical features of ARS vary significantly based on the affected gene, it is critical that families are provided with a gene-specific diagnosis, PITX2-related ARS or FOXC1-related ARS. De Hauwere syndrome is proposed to be a FOXC1opathy.

Association between myopia progression and quantity of laser treatment for retinopathy of prematurity.

BACKGROUND: Previous studies found that infants with retinopathy of prematurity (ROP) who were treated for more posterior disease with a greater number of laser spots developed higher myopia. These studies included multiple physicians with variations in laser density. In treatments by a single physician, laser spot count is a better surrogate for area of avascular retina and anterior-posterior location of disease, so that the relationship with myopia can be better assessed. METHODS: Our retrospective study included infants treated with laser for ROP by a single surgeon at a single center. Exclusion criteria were irregularities during laser and additional treatment for ROP. We assessed correlation between laser spot count and change in refractive error over time using a linear mixed effects model. RESULTS: We studied 153 eyes from 78 subjects treated with laser for ROP. The average gestational age at birth was 25.3±1.8 weeks, birth weight 737±248 grams, laser spot count 1793±728, and post-treatment follow up 37±29 months. Between corrected ages 0-1 years, the mean spherical equivalent was +0.4±2.3 diopters; between ages 1-2, it was -1.3±3.2D; and ages 2-3 was -0.8±3.1D. Eyes that received more laser spots had significantly greater change in refractive error over time (0.30D more myopia per year per 1000 spots). None of the eyes with hyperopia before 18 months developed myopia during the follow-up period. CONCLUSIONS: Greater myopia developed over time in infants with ROP treated by laser to a larger area of avascular retina.

Decorin Concentrations in Aqueous Humor of Patients with Diabetic Retinopathy.

Diabetic retinopathy (DR) is a microvascular complication of diabetes in the retina. Chronic hyperglycemia damages retinal microvasculature embedded into the extracellular matrix (ECM), causing fluid leakage and ischemic retinal neovascularization. Current treatment strategies include intravitreal anti-vascular endothelial growth factor (VEGF) or steroidal injections, laser photocoagulation, or vitrectomy in severe cases. However, treatment may require multiple modalities or repeat treatments due to variable response. Though DR management has achieved great success, improved, long-lasting, and predictable treatments are needed, including new biomarkers and therapeutic approaches. Small-leucine rich proteoglycans, such as decorin, constitute an integral component of retinal endothelial ECM. Therefore, any damage to microvasculature can trigger its antifibrotic and antiangiogenic response against retinal vascular pathologies, including DR. We conducted a cross-sectional study to examine the association between aqueous humor (AH) decorin levels, if any, and severity of DR. A total of 82 subjects (26 control, 56 DR) were recruited. AH was collected and decorin concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). Decorin was significantly increased in the AH of DR subjects compared to controls (p = 0.0034). AH decorin levels were increased in severe DR groups in ETDRS and Gloucestershire classifications. Decorin concentrations also displayed a significant association with visual acuity (LogMAR) measurements. In conclusion, aqueous humor decorin concentrations were found elevated in DR subjects, possibly due to a compensatory response to the retinal microvascular changes during hyperglycemia.

Syphilitic interstitial keratitis treated with topical tacrolimus.

PURPOSE: To report a case of syphilitic interstitial keratitis successfully managed with topical tacrolimus after the development of steroid-induced intraocular pressure elevation in a pediatric patient. OBSERVATIONS: A 4-year-old female with a history of congenital syphilis that was reportedly treated after birth presented with bilateral conjunctival redness, tearing, and photosensitivity. Initial ophthalmic examination revealed corneal vascularization with diffuse haze of the right eye and circumferential vascularization with stromal infiltrates of the left eye. She was diagnosed with bilateral syphilitic interstitial keratitis and initially managed with topical steroids but developed steroid-induced elevation of her intraocular pressure. She experienced several recurrences of keratitis as steroids were tapered. After a recurrence in her right eye, she was treated with topical tacrolimus. Since then, she has remained recurrence-free for almost three years with normal intraocular pressure. CONCLUSION AND IMPORTANCE: Tacrolimus represents a novel alternative for the treatment of syphilitic interstitial keratitis, which is particularly useful in patients that develop elevated intraocular pressures in response to long-term treatment with steroid eye drops.

Small Leucine-Rich Proteoglycans (SLRPs) in the Retina.

Retinal diseases such as age-related macular degeneration (AMD), retinopathy of prematurity (ROP), and diabetic retinopathy (DR) are the leading causes of visual impairment worldwide. There is a critical need to understand the structural and cellular components that play a vital role in the pathophysiology of retinal diseases. One potential component is the family of structural proteins called small leucine-rich proteoglycans (SLRPs). SLRPs are crucial in many fundamental biological processes involved in the maintenance of retinal homeostasis. They are present within the extracellular matrix (ECM) of connective and vascular tissues and contribute to tissue organization and modulation of cell growth. They play a vital role in cell-matrix interactions in many upstream signaling pathways involved in fibrillogenesis and angiogenesis. In this comprehensive review, we describe the expression patterns and function of SLRPs in the retina, including Biglycan and Decorin from class I; Fibromodulin, Lumican, and a Proline/arginine-rich end leucine-rich repeat protein (PRELP) from class II; Opticin and Osteoglycin/Mimecan from class III; and Chondroadherin (CHAD), Tsukushi and Nyctalopin from class IV.

Examining Whether AOSLO-Based Foveal Cone Metrics in Achromatopsia and Albinism Are Representative of Foveal Cone Structure.

Purpose: Adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in patients with achromatopsia (ACHM) and albinism is not always successful. Here, we tested whether optical coherence tomography (OCT) measures of foveal structure differed between patients for whom AOSLO images were either quantifiable or unquantifiable. Methods: The study included 166 subjects (84 with ACHM; 82 with albinism) with previously acquired OCT scans, AOSLO images, and best-corrected visual acuity (BCVA, if available). Foveal OCT scans were assessed for outer retinal structure, outer nuclear layer thickness, and hypoplasia. AOSLO images were graded as quantifiable if a peak cone density could be measured and/or usable if the location of peak density could be identified and the parafoveal mosaic was quantifiable. Results: Forty-nine percent of subjects with ACHM and 57% of subjects with albinism had quantifiable AOSLO images. Older age and better BCVA were found in subjects with quantifiable AOSLO images for both ACHM (P = 0.0214 and P = 0.0276, respectively) and albinism (P = 0.0073 and P < 0.0004, respectively). There was a significant trend between ellipsoid zone appearance and ability to quantify AOSLO (P = 0.0028). In albinism, OCT metrics of cone structure did not differ between groups. Conclusions: Previously reported AOSLO-based cone density measures in ACHM may not necessarily reflect the degree of remnant cone structure in these patients. Translational Relevance: Until AOSLO is successful in all patients with ACHM and albinism, the possibility of the reported data from a particular cohort not being representative of the entire population remains an important issue to consider when interpreting results from AOSLO studies.

Dominant variants in PRR12 result in unilateral or bilateral complex microphthalmia.

Complex microphthalmia is characterized by small eyes with additional abnormalities that may include anterior segment dysgenesis. While many genes are known, a genetic cause is identified in only 4-30% of microphthalmia, with the lowest rate in unilateral cases. We identified four novel pathogenic loss-of-function alleles in PRR12 in families affected by complex microphthalmia and/or Peters anomaly, including two de novo, the first dominantly transmitted allele, as well as the first splicing variant. The ocular phenotypes were isolated with no additional systemic features observed in two unrelated families. Remarkably, ocular phenotypes were asymmetric in all individuals and unilateral (with structurally normal contralateral eye) in three. There are only three previously reported PRR12 variants identified in probands with intellectual disability, neuropsychiatric disorders, and iris anomalies. While some overlap with previously reported cases is seen, nonsyndromic developmental ocular anomalies are a novel phenotype for this gene. Additional phenotypic expansions included short stature and normal development/cognition, each noted in two individuals in this cohort, as well as absence of neuropsychiatric disorders in all. This study identifies new associations for PRR12 disruption in humans and presents a genetic diagnosis resulting in unilateral ocular phenotypes in a significant proportion of cases.

Survey of practice patterns for the management of ophthalmic genetic disorders among AAPOS members: report by the AAPOS Genetic Eye Disease Task Force.

To better understand AAPOS member pediatric ophthalmologists' knowledge and needs regarding genetic eye disorders, the AAPOS Genetic Eye Disease Task Force developed a 16-question survey that was circulated to national and international AAPOS members. Responses to questions on practice patterns, baseline knowledge, and educational interests regarding patients with suspected ophthalmic genetic disorders were collected. A majority of respondents (93%) evaluate patients with suspected genetic disorders. Knowledge gaps were present in heritability of certain conditions, genetic testing strategies, and referral to clinical trials. Most respondents expressed interest in further education in these areas. A model for care is proposed as a first step in the education process.

Surgical Timing for Congenital Ptosis Should Not Be Determined Solely by the Presence of Anisometropia.

PURPOSE: Timing of surgery in children with congenital ptosis is a critical component of care, and anisometropia is frequently cited as an indication for early intervention. The purpose of this study is to evaluate the change in refractive error following surgery for congenital ptosis to better inform decisions regarding the timing of surgery. METHODS: A retrospective review of clinical records was performed on patients who underwent surgical correction of congenital ptosis in an academic oculoplastic surgery practice from 2002 to 2017. Patients with complete preoperative and postoperative refractive data were included in the study. Changes in refractive error following surgery were analyzed. RESULTS: Among 184 pediatric patients who underwent ptosis surgery during the study period, 56 patients (71 eyes) met inclusion criteria. The mean age at surgery was 5.1 years. Mean refractive error change in all the operated eyes was a 0.82 D decrease in spherical equivalent (p = 0.1920) and a 0.40 D increase in cylinder (p = 0.0255). There were no statistically significant changes in spherical equivalent or cylinder in the control eyes. CONCLUSIONS: The authors data did not show movement toward normalization of refractive error following ptosis surgery. In fact, it showed a statistically significant worsening of astigmatism following surgery. Because refractive error does not improve following surgery, anisometropia should not be the sole indication for early surgery in congenital ptosis.

Findings in Persistent Retinopathy of Prematurity.

BACKGROUND AND OBJECTIVE: To determine whether retinopathy of prematurity (ROP) that persists beyond a postmenstrual age (PMA) of 45 weeks has abnormalities that can be documented by fundus photography or fluorescein angiography (FA). PATIENTS AND METHODS: Fundus photographs and FAs were reviewed for all premature infants who underwent FA for persistent ROP after 45 weeks PMA. RESULTS: Of the 487 infants who were screened for ROP, 16 (3.3%) demonstrated ROP beyond 45 weeks. Seven (43.8%) infants received prior treatment with intravitreal bevacizumab (IVB) for Type 1 ROP. FAs were obtained in eight cases; four subjects were previously treated with IVB. Leakage at the vascular-avascular border was demonstrated in seven subjects (87.5%). Shunt vessels, posterior retinal nonperfusion, and absence of the foveal avascular zone was limited to the IVB group. CONCLUSIONS: There are persistent vascular abnormalities among infants with ROP beyond 45 weeks. Findings that may be missed by RetCam fundus photographs were highlighted with FA. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:497-503.].

Foveal Development in Infants Treated with Bevacizumab or Laser Photocoagulation for Retinopathy of Prematurity.

PURPOSE: To characterize and quantify early foveal development in preterm infants and to compare this development between eyes treated with intravitreal bevacizumab or laser photocoagulation (LPC) and untreated eyes. DESIGN: Observational case series. PARTICIPANTS: One hundred thirty-one preterm infants undergoing retinopathy of prematurity (ROP) screenings. METHODS: Handheld OCT imaging was performed longitudinally on all patients. Thickness measurements of the inner and outer retinal layers were obtained at the foveal center and the nasal and temporal foveal rims. Comparisons between treated and untreated eyes were adjusted for age and other confounding variables. MAIN OUTCOME MEASURES: Weekly change in inner and outer retinal thickness and presence of inner retinal layers, ellipsoid zone (EZ), and cystoid macular changes (CMCs). RESULTS: Outer retinal thickness at the foveal center increased by 3.1 µm/week in untreated eyes and 7.2 µm/week in bevacizumab-treated eyes (P = 0.038). Eyes treated with LPC had a lower probability of having all inner retinal layers present at the foveal center (odds ratio, 0.04; P = 0.001) and a lower probability of having the EZ present at the foveal center (odds ratio, 0.07; P = 0.024) compared with untreated eyes. Cystoid macular changes were found in 53% of patients and 22% of imaging sessions. The age-adjusted incidence of CMCs was not correlated with bevacizumab or LPC treatment. CONCLUSIONS: Intravitreal bevacizumab therapy for ROP is associated with more rapid outer retinal thickening at the foveal center, whereas LPC is associated with earlier extrusion of the inner retinal layers and delayed development of the EZ at the foveal center. Long-term follow-up is needed to determine the visual significance of these findings.

Histopathological analysis of retinopathy of prematurity after intravitreal bevacizumab.

We report the case of a premature infant with end-organ failure who developed high-risk retinopathy of prematurity (ROP) bilaterally and was treated with intravitreal bevacizumab (IVB) injection therapy with regression noted on follow-up clinical examination. The infant died 3 weeks after IVB injection therapy. Histopathological analysis was conducted on bilateral globes and revealed persistent preretinal vessels.

Analysis of CYP1B1 in pediatric and adult glaucoma and other ocular phenotypes.

PURPOSE: The CYP1B1 gene encodes an enzyme that is a member of the cytochrome P450 superfamily. Mutations in CYP1B1 have been mainly reported in recessive pediatric ocular phenotypes, such as primary congenital glaucoma (PCG) and congenital glaucoma with anterior segment dysgenesis (CG with ASD), with some likely pathogenic variants also identified in families affected with adult-onset primary open angle glaucoma (POAG). METHODS: We examined CYP1B1 in 158 pediatric patients affected with PCG (eight), CG with ASD (22), CG with other developmental ocular disorders (11), juvenile glaucoma with or without additional ocular anomalies (26), and ASD or other developmental ocular conditions without glaucoma (91); in addition, a large cohort of adult patients with POAG (193) and POAG-negative controls (288) was examined. RESULTS: Recessive pathogenic variants in CYP1B1 were identified in two PCG pedigrees, three cases with CG and ASD, and two families with CG and other ocular defects, such as sclerocornea in one patient and microphthalmia in another individual; neither sclerocornea nor microphthalmia has been previously associated with CYP1B1. Most of the identified causative mutations are new occurrences of previously reported pathogenic alleles with two novel variants identified: a c.1325delC, p.(Pro442Glnfs*15) frameshift allele in a family with PCG and a c.157G>A, p.(Gly53Ser) variant identified in a proband with CG, Peters anomaly, and microphthalmia. Analysis of the family history in the CYP1B1-positive families revealed POAG in confirmed or presumed heterozygous relatives in one family with PCG and two families with ASD/CG; POAG was associated with the c.1064_1076del, p.(Arg355Hisfs*69) allele in two of these pedigrees. Screening of an unrelated POAG cohort identified the same c.1064_1076del heterozygous allele in one individual with sporadic POAG but not in age- and ethnicity-matched POAG-negative individuals. Overall, there was no significant enrichment for mutant alleles in CYP1B1 within the POAG cases compared to the controls. CONCLUSIONS: In summary, these data expand the mutational and phenotypic spectra of CYP1B1 to include two novel alleles and additional developmental ocular phenotypes. The contribution of CYP1B1 to POAG is less clear, but loss-of-function variants in CYP1B1, especially c.1064_1076del, p.(Arg355Hisfs*69), may be associated with an increased risk for POAG.

Case report of homozygous deletion involving the first coding exons of GCNT2 isoforms A and B and part of the upstream region of TFAP2A in congenital cataract.

BACKGROUND: Congenital cataracts affect 3-6 per 10,000 live births and represent one of the leading causes of blindness in children. Congenital cataracts have a strong genetic component with high heterogeneity and variability. CASE PRESENTATION: Analysis of whole exome sequencing data in a patient affected with congenital cataracts identified a pathogenic deletion which was further defined by other techniques. A ~98-kb homozygous deletion of 6p24.3 involving the first three exons (two non-coding and one coding) of GCNT2 isoform A, the first exon (coding) of GCNT2 isoform B, and part of the intergenic region between GCNT2 and TFAP2A was identified in the patient and her brother while both parents were found to be heterozygous carriers of the deletion. The exact breakpoints were identified and revealed the presence of Alu elements at both sides of the deletion, thus indicating Alu-mediated non-homologous end-joining as the most plausible mechanism for this rearrangement. Recessive mutations in GCNT2 are known to cause an adult i blood group phenotype with congenital cataracts in some cases. The GCNT2 gene has three differentially expressed transcripts, with GCNT2B being the only isoform associated with lens function and GCNT2C being the only isoform expressed in red blood cells based on earlier studies; previously reported mutations/deletions have either affected all three isoforms (causing blood group and cataract phenotype) or the C isoform only (causing blood group phenotype only). Dominant mutations in TFAP2A are associated with syndromic anophthalmia/microphthalmia and other ocular phenotypes as part of Branchio-Ocular-Facial-Syndrome (BOFS). While the patients do not fit a diagnosis of BOFS, one sibling demonstrates mild overlap with the phenotypic spectrum, and therefore an effect of this deletion on the function of TFAP2A cannot be ruled out. CONCLUSIONS: To the best of our knowledge, this is the first case reported in which disruption of the GCNT2 gene does not involve the C isoform. The congenital cataracts phenotype in the affected patients is consistent with the previously defined isoform-specific roles of this gene. The GCNT2-TFAP2A region may be prone to rearrangements through Alu-mediated non-homologous end-joining.

ATTENUATION OF THE GANGLION CELL LAYER IN A PREMATURE INFANT REVEALED WITH HANDHELD SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To report on subclinical retinal abnormalities shown through handheld spectral domain optical coherence tomography on a premature infant. METHODS: Case report. RESULTS: The initial and follow-up exams on a premature infant revealed severely attenuated ganglion cell and nerve fiber layers. There was cystoid macular edema in both eyes at the initial visits, which resolved by the 1-year follow-up. DISCUSSION: Optical coherence tomography can reveal significant retinal abnormalities in premature infants which are not detectable through funduscopic exam. Documenting such findings may be useful for the comprehensive management of vision problems in children with a history of premature birth.

Relationship between foveal cone specialization and pit morphology in albinism.

PURPOSE: Albinism is associated with disrupted foveal development, though intersubject variability is becoming appreciated. We sought to quantify this variability, and examine the relationship between foveal cone specialization and pit morphology in patients with a clinical diagnosis of albinism. METHODS: We recruited 32 subjects with a clinical diagnosis of albinism. DNA was obtained from 25 subjects, and known albinism genes were analyzed for mutations. Relative inner and outer segment (IS and OS) lengthening (fovea-to-perifovea ratio) was determined from manually segmented spectral domain-optical coherence tomography (SD-OCT) B-scans. Foveal pit morphology was quantified for eight subjects from macular SD-OCT volumes. Ten subjects underwent imaging with adaptive optics scanning light ophthalmoscopy (AOSLO), and cone density was measured. RESULTS: We found mutations in 22 of 25 subjects, including five novel mutations. All subjects lacked complete excavation of inner retinal layers at the fovea, though four subjects had foveal pits with normal diameter and/or volume. Peak cone density and OS lengthening were variable and overlapped with that observed in normal controls. A fifth hyper-reflective band was observed in the outer retina on SD-OCT in the majority of the subjects with albinism. CONCLUSIONS: Foveal cone specialization and pit morphology vary greatly in albinism. Normal cone packing was observed in the absence of a foveal pit, suggesting a pit is not required for packing to occur. The degree to which retinal anatomy correlates with genotype or visual function remains unclear, and future examination of larger patient groups will provide important insight on this issue.