Genetic testing for inherited ocular conditions in a developing country.

Background: Inherited ocular conditions are a frequent cause of blindness. Gene therapy has encouraged the development of genetic testing, currently able to detect up to 80% of mutations in contrast to the 5% sensitivity achieved a few decades ago.Materials and methods: One hundred sixty-three patients with suspected genetic ocular disorders who were referred to a single clinician between August 2014 and August 2019 underwent a thorough ophthalmologic examination. Those diagnosed with congenital cataract, retinoblastoma, anterior segment dysgenesis, autoimmune retinal disease, posterior microphthalmia, or cobalamin C deficiency were excluded, along with patients who opted against genetic testing. Included probands were classified into a diagnostic clinical category and offered genetic testing. Blood samples were sent to foreign accredited diagnostic laboratories, followed by clinical interpretation of the results.Results: Of the 163 patients referred, 104 were enrolled in the study. Median age at disease onset was 2 years (range, 0 to 43 years). A molecular diagnosis was established at a median age of 10 years (range, 0.4 to 50 years). Disease-causing genotypes were identified in 82 of the probands, indicating a mutation detection rate of 78.8%. Mutations were identified in 38 genes, ABCA4 being the most commonly affected (23% of mutations), followed by CRB1 (13% of mutations). Whole-exome sequencing was performed in 6 patients, resulting in a definite diagnosis in 3 (50%).Conclusions: Molecular testing for inherited ocular conditions is feasible in developing countries by sending samples to certified foreign laboratories, with a mutation detection rate comparable to published values in developed countries. Further studies to identify more disease-causing genes may improve the overall sensitivity.

The Oculome Panel Test: Next-Generation Sequencing to Diagnose a Diverse Range of Genetic Developmental Eye Disorders.

PURPOSE: To develop a comprehensive next-generation sequencing panel assay that screens genes known to cause developmental eye disorders and inherited eye disease and to evaluate its diagnostic yield in a pediatric cohort with malformations of the globe, anterior segment anomalies, childhood glaucoma, or a combination thereof. DESIGN: Evaluation of diagnostic test. PARTICIPANTS: Two hundred seventy-seven children, 0 to 16 years of age, diagnosed with nonsyndromic or syndromic developmental eye defects without a genetic diagnosis. METHODS: We developed a new oculome panel using a custom-designed Agilent SureSelect QXT target capture method (Agilent Technologies, Santa Clara, CA) to capture and perform parallel high-throughput sequencing analysis of 429 genes associated with eye disorders. Bidirectional Sanger sequencing confirmed suspected pathogenic variants. MAIN OUTCOME MEASURES: Collated clinical details and oculome molecular genetic results. RESULTS: The oculome design covers 429 known eye disease genes; these are subdivided into 5 overlapping virtual subpanels for anterior segment developmental anomalies including glaucoma (ASDA; 59 genes), microphthalmia-anophthalmia-coloboma (MAC; 86 genes), congenital cataracts and lens-associated conditions (70 genes), retinal dystrophies (RET; 235 genes), and albinism (15 genes), as well as additional genes implicated in optic atrophy and complex strabismus (10 genes). Panel development and testing included analyzing 277 clinical samples and 3 positive control samples using Illumina sequencing platforms; more than 30× read depth was achieved for 99.5% of the targeted 1.77-Mb region. Bioinformatics analysis performed using a pipeline based on Freebayes and ExomeDepth to identify coding sequence and copy number variants, respectively, resulted in a definitive diagnosis in 68 of 277 samples, with variability in diagnostic yield between phenotypic subgroups: MAC, 8.2% (8 of 98 cases solved); ASDA, 24.8% (28 of 113 cases solved); other or syndromic, 37.5% (3 of 8 cases solved); RET, 42.8% (21 of 49 cases solved); and congenital cataracts and lens-associated conditions, 88.9% (8 of 9 cases solved). CONCLUSIONS: The oculome test diagnoses a comprehensive range of genetic conditions affecting the development of the eye, potentially replacing protracted and costly multidisciplinary assessments and allowing for faster targeted management. The oculome enabled molecular diagnosis of a significant number of cases in our sample cohort of varied ocular birth defects.

Ocular manifestations of Emanuel syndrome.

Emanuel syndrome is caused by a supernumerary der(22)t(11;22) and typically manifests with intellectual disability and craniofacial dysmorphism. Ocular abnormalities have infrequently been described. We report a 36-year-old man with severe intellectual disability, aphasia, and facial dysmorphism, with high myopia and juvenile open angle glaucoma (JOAG). Microarray analysis results included 47,XY,+der(22)t(11;22)(q23;q11.2), and a 269 kb deletion of 7q31.33(125,898,014-126,166,829). Two candidate genes were identified as possible etiologies for the ocular pathologies in our patient: a MFRP duplication on chromosome 11, which may play a role in high myopia and dysregulation of emmetropization, and a GRM8 deletion on chromosome 7, which may cause glutamate-induced excitotoxicity and therefore have a role in the development of JOAG, unrelated to the Emanuel syndrome genotype. We provide the first detailed description these ocular abnormalities in a patient with Emmanuel syndrome.

A national telemedicine network for retinopathy of prematurity screening.

PURPOSE: To report the results of retinopathy of prematurity (ROP) screening by a telemedicine system in Chile and evaluate its usefulness for referring patients who require treatment. METHODS: Premature infants at risk of developing ROP from 11 neonatal intensive care units were included. Screening was performed on all infants born at a gestational age of <32 weeks and/or birth weight of <1500 g. A trained nonphysician operator used an imaging system to capture retinal images, which were reviewed by two independent ROP experts. All infants that required treatment were referred for further evaluation. RESULTS: The study included 2,048 eyes of 1,024 premature infants. Mean gestational age was 28.8 ± 2.2 weeks, and mean birth weight was 1128 ± 279 g. A total of 5,263 telemedicine examinations were performed and reported. The average number of image sets per patient was 2.6 ± 2.5. Of the 5,263 images, 4,903 (93%) were recorded to at least the end of zone II; 5,172 (98%) were graded as having good quality, allowing for staging of ROP disease. Forty-two infants (4%) were referred for treatment. Discharged patients with ROP type 2 that regressed did not present with any complications or adverse effects during 6 months' follow-up. CONCLUSIONS: Our study demonstrates the utility of telemedicine screening for ROP with ophthalmologist readers in a developing country. Telemedicine screening was able to detect treatment-requiring ROP. Most of the images had good quality and showed the end of zone II, two variables sufficient to discharge patients.

Visual outcome following bilateral non-arteritic anterior ischemic optic neuropathy: a systematic review and meta-analysis.

BACKGROUND: Many patients who suffer unilateral non-arteritic anterior ischemic optic neuropathy (NAION) will eventually develop the same condition in their other eye, worrying them about losing vision in both eyes. The purpose of this meta-analysis is to determine whether it is possible to predict the visual outcome of the consecutive NAION event based on initial presentation and to compare mean visual loss of firstly versus secondly affected eyes. METHODS: A systematic review and meta-analysis of studies published between January 1st 1966 and May 31st 2016 reporting on visual acuity and/or visual field loss of both affected eyes, measured either at presentation or follow-up following bilateral NAION. RESULTS: Ten studies were included in the meta- analysis of visual acuity, including 9 retrospective reports and one randomized clinical trial, and five retrospective studies were included in visual field meta-analysis. A significant correlation exists for visual acuity (R = 0.387, P < 0.001) in both eyes of the same patient following bilateral NAION, and also for visual field loss (R = 0.445, P < 0.001) in the two eyes. The calculated coefficient of determination (R2) of 0.149 for visual acuity, and 0.198 for visual field loss indicates that for any given individual suffering from unilateral NAION only 15% of visual acuity and 20% of visual field loss in the secondly affected eye can be explained by these outcomes in the first eye. In addition, there was no difference in mean visual outcome of the first versus second NAION events (standardized mean differences of visual acuity 0.008, P = 0.890; and visual field loss, -0.019, P = 0.819). CONCLUSION: Even though a weak connection exists between visual outcome in both eyes following bilateral NAION it is still impossible to predict with certainty the visual outcome of a sequential contralateral NAION event based on the severity of visual loss in the first affected eye. Measures often taken after the first event are ineffective in improving the visual outcome of a second event should it occur.

Bilateral retinoblastoma with one eye manifesting only posterior chamber infiltration and no retinal involvement.

We report the case of a 23-month-old girl with bilateral retinoblastoma that demonstrated absence of retinal lesions in one eye but had an isolated white tumor in the posterior chamber. Genetic testing confirmed a novel and de novo RB1 germline mutation in the proband that was not carried by her parents. After intravenous chemotherapy and brachytherapy to the eye with apparently disease-free retina, anatomic and functional preservation of the eye was achieved. The patient has been in remission for 18 months.

How genetics works? An illustrative case report.

In this communication, we report the case of a four year old boy who presented with reduced vision in the right eye. He had visual acuity of light perception right eye and 6/12 in the left eye and anterior segment examination was normal. Fundus examination of the right eye showed a falciform retinal fold extending from the optic nerve temporally involving the entire retina with exudates within the falciform fold and dense pigmentation peripherally. The left eye showed mild macular temporal dragging of the vessels and 360° of peripheral laser scars. In addition he also had some characteristic systemic features such as developmental delay, obesity, dysmorphic facies and tapered fingers. Using this case as an example, we present a systematic, logical approach to a patient with a possible genetic disorder. The growing field of ocular genetics now allows for improved diagnosis using step-wise cost efficient testing as demonstrated herein.

Combined Phacoemulsification and Ahmed Glaucoma Drainage Implant Surgery for Patients With Refractory Glaucoma and Cataract.

PURPOSE: To examine the indications, safety, efficacy, and complications of combined phacoemulsification and Ahmed glaucoma drainage implant surgery. METHODS: A retrospective case review of 35 eyes (31 patients) subjected to combined phacoemulsification and Ahmed glaucoma drainage implant surgery. Demographic characteristics of the study population, indications for combined surgery, and operative and postoperative complications were recorded. Visual acuity, intraocular pressure (IOP), and number of glaucoma medications were evaluated preoperatively and postoperatively. Complete success was defined as IOP ≤ 21 mm Hg without medication, qualified success if IOP ≤ 21 mm Hg with ≥ 1 medications, and failure if IOP>21 mm Hg or ≤ 5 mm Hg on ≥ 2 consecutive visits. RESULTS: Mean follow-up was 29.5 months (range, 6 to 87 mo). The most common indication for combined surgery was a history of prior failed trabeculectomy (60%). Postoperative visual acuity improved in 30 of 35 eyes (85%) (P<0.01) regardless of the indication for combined surgery. IOP was reduced from a mean of 24.7 to 15.0 mm Hg at the last follow-up visit (P<0.01). The number of IOP-lowering medications was reduced from a median of 3.1 preoperatively to 1.7 at the last follow-up (P<0.01). Overall, there were 31 eyes (89%) classified as qualified success and 4 eyes (11%) as complete success. The most common postoperative complication was a hypertensive phase in 18 eyes (51%). CONCLUSIONS: Combined phacoemulsification and Ahmed glaucoma drainage implant surgery seems to be a safe and effective surgical option, providing good visual rehabilitation and control of IOP for patients with refractory glaucoma and cataract.

Unusual retinal abnormalities in sisters with tetralogy of Fallot.

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease and can occur in the setting of chromosomal aberrations or multisystem malformation syndromes. We report unusual focal bilateral retinal defects in sisters with TOF.

Using cost-effective intra-arterial chemotherapy to treat retinoblastoma in Chile.

Intra-arterial chemotherapy (IAC) has proved to be an effective treatment for retinoblastoma, but can be very expensive in developing countries. We report 2 patients from Chile in whom IAC resulted in globe salvation. Both patients had their medical care provided by the public health system and had failed standard therapy.

Should patients with ocular genetic disorders have genetic testing?

PURPOSE OF REVIEW: To discuss the risks, benefits and value of genetic testing for ocular genetic disease. RECENT FINDINGS: Testing for ocular genetics diseases is becoming more available and successful gene therapy is being reported. Clinicians must prepare for this trend by considering diagnostic genetic testing for their patients. SUMMARY: As advances continually occur in genetic testing for ocular genetic disorders, clinicians must develop an understanding of the potential risks and benefits for their patients.

Dynamics of tear fluid desiccation on a glass surface: a contribution to tear quality assessment.

BACKGROUND: Fern-like crystalloids form when a microvolume of tear is allowed to dry out at ambient conditions on a glass surface. Presence of crystalloids in tear "microdesiccates" is used to evaluate patients with Dry-Eye disease. This study aims to examine morphologically the desiccation process of normal tear fluid and to identify changes associated with accelerated tear evaporation. Tear microdesiccates from healthy (Non-Dry Eye) and Dry Eye subjects were produced at ambient conditions. Microdesiccate formation was monitored continuously by dark-field video microscopy. Additionally, accelerated desiccation of tear samples from healthy subjects was conducted under controlled experimental conditions. Particular morphological domains of tear microdesiccates and their progressive appearance during desiccation were compared. RESULTS: In normal tear microdesiccates, four distinctive morphological domains (zones I, II, III and transition band) were recognized. Stepwise formation of those domains is now described. Experimentally accelerated desiccation resulted in marked changes in some of those zones, particularly involving either disappearance or size reduction of fern-like crystalloids of zones II and III. Tear microdesiccates from Dry Eye subjects may also display those differences and be the expression of a more synchronous formation of microdesiccate domains. CONCLUSION: Morphological characteristics of tear microdesiccates can provide insights into the relative rate of tear evaporation.

Dynamics of tear fluid desiccation on a glass surface: a contribution to tear quality assessment

BACKGROUND: Fern-like crystalloids form when a microvolume of tear is allowed to dry out at ambient conditions on a glass surface. Presence of crystalloids in tear "microdesiccates" is used to evaluate patients with Dry-Eye disease. This study aims to examine morphologically the desiccation process of normal tear fluid and to identify changes associated with accelerated tear evaporation. Tear microdesiccates from healthy (Non-Dry Eye) and Dry Eye subjects were produced at ambient conditions. Microdesiccate formation was monitored continuously by dark-field video microscopy. Additionally, accelerated desiccation of tear samples from healthy subjects was conducted under controlled experimental conditions. Particular morphological domains of tear microdesiccates and their progressive appearance during desiccation were compared. RESULTS: In normal tear microdesiccates, four distinctive morphological domains (zones I, II, III and transition band) were recognized. Stepwise formation of those domains is now described. Experimentally accelerated desiccation resulted in marked changes in some of those zones, particularly involving either disappearance or size reduction of fern-like crystalloids of zones II and III. Tear microdesiccates from Dry Eye subjects may also display those differences and be the expression of a more synchronous formation of microdesiccate domains. CONCLUSION: Morphological characteristics of tear microdesiccates can provide insights into the relative rate of tear evaporation.

Esotropia surgery in children with Down syndrome.

PURPOSE: To evaluate postoperative alignment in children with and without Down syndrome after surgical correction of esotropia. METHODS: The medical records of consecutive patients with Down syndrome who underwent corrective surgery for esotropia between August 1992 and July 2012 were retrospectively reviewed. Age range for eligibility was between 8 months and 17 years at surgery. The control group comprised randomly selected, age-matched patients without Down syndrome who underwent the same surgical procedure. Postoperative alignment within 10(Δ) of orthotropia at 6 months' follow-up and at the final postoperative visit was considered a successful outcome. RESULTS: A total of 17 children with Down syndrome and 27 control subjects were included. The control group and Down syndrome group did not differ significantly in either postoperative follow-up (5.2 ± 3.2 versus 5.6 ± 5.2 years, respectively) or magnitude of deviation before surgery (40 ± 18.2(Δ) versus 39 ± 12.8(Δ), respectively). Surgical success was achieved in 76% of patients with Down syndrome and in 85% of control patients at 6 months' follow-up. CONCLUSIONS: In this patient cohort, good surgical outcomes were achieved in children with esotropia and Down syndrome compared with those with esotropia but without Down syndrome using the same surgical technique.

Residual internal limiting membrane after epiretinal membrane peeling: results of the Pan-American Collaborative Retina Study Group.

PURPOSE: To determine the degree of residual internal limiting membrane (ILM) after idiopathic epiretinal membrane (ERM) peeling and the usefulness of staining with brilliant blue G. METHODS: A prospective, multicenter, observational study of 98 eyes undergoing pars plana vitrectomy and membrane peeling for idiopathic ERM. All eyes underwent core vitrectomy (20, 23, or 25 gauge) followed by intravitreal triamcinolone to verify that the posterior hyaloid had been removed. Brilliant blue G (0.2 mL of 0.25 mg/mL) was injected into the vitreous cavity and washed out immediately. The ERM was peeled and then the surgeon observed and recorded the characteristics of the underlying ILM. The posterior pole was restained with brilliant blue G (0.2 mL of 0.25 mg/mL), and the same observations on the characteristics of the ILM were recorded. Peeling of the remaining ILM was performed. The main outcome measured was the status of the ILM after ERM peel. Secondary outcomes included best-corrected visual acuity and central macular thickness at 6 months postoperatively. RESULTS: After ERM peel, all of the eyes had residual ILM. In 74 eyes, the ILM was present and damaged, whereas in 24 eyes, the ILM was present and undamaged. In 37 eyes, the operating surgeon was unable to determine the status of the ILM before brilliant blue G staining. At 6 months, the logarithm of the minimum angle of resolution best-corrected visual acuity improved from 0.75 ± 0.39 at baseline to 0.31 ± 0.26 (P < 0.0001). The central macular thickness also improved from 460 ± 91 µm at baseline to 297 ± 102 µm (P < 0.003). CONCLUSION: Internal limiting membrane is frequently still present after ERM peeling. Staining with brilliant blue G facilitates its identification.

Frequent Evaluation To Improve Compliance In Patients Treated With Occlusion For Amblyopia: A Randomized controlled Trial.

BACKGROUND: The benefits of occlusion treatment for amblyopia are well established.True compliance can be difficult to assess and is usually based on patient history. We hypothesize that more visits to the physician provides more chances to improve compliance. METHODS: We conducted a prospective, comparative, blind trial in which 30 children with amblyopia were randomly assigned to be followed up more frequently (every 4 to 6 weeks) (study group) or as established on our standard regular basis (month intervals based on age in years) (control group). The primary outcome was to study differences in treatment compliance between these groups. The secondary outcome was to report compliance in a group of Chilean children and to compare survey results with adherence, to assess concordance between them. RESULTS: Baseline clinical characteristics were similar in the two groups. 30 patients were recruited. Mean compliance for all patients was 82%. Study group compliance was 83% versus 76% in control group (p = 0.5). Without epidemiology, intention to treat analysis (ITT), study group compliance was 97% compared to 76% in control group (p = 0.049). Pearson correlation between negative responses to a parental survey after treatment, of the percentage of adherence and compliance, was -0.57 and statistically significant (p = 0.013). CONCLUSIONS: There were no differences in patient compliance comparing more frequent evaluation versus a follow up evaluation based in an age according scheme. There is a high compliance to occlusion therapy in this group of Chilean children. If parents reported more negative adherence aspects in the survey, the worse the compliance.

[Natural history of diabetic retinopathy in a retrospective cohort of type 1 diabetics]. / Historia natural de retinopatía diabética en un estudio a largo plazo en pacientes con diabetes tipo 1. Factores de riesgo para progresión a enfermedad proliferante.

BACKGROUND: Diabetic retinopathy is one of the most common causes of blindness among adults. AIM: To report the natural history of diabetic retinopathy among Chilean patients with type 1 diabetes followed for a mean of 18 years. MATERIAL AND METHODS: Retrospective review of medical records of 39 patients aged 26 to 70 years, (20 females, 78 eyes) with type 1 diabetes controlled by the same ophthalmologist from 1971 to 2008. A questionnaire was sent to each patient and their treating physician to request information about the evolution of the disease and metabolic control. RESULTS: The questionnaire was answered by 24 patients (62%) and 21 attending physicians (54%). Small hard drusen were observed in 25 patients (64%). In 12 cases the drusen were detected before the development of any type of retinopathy. Eleven women became pregnant and retinopathy progressed in four of them. Twenty three patients (59%) developed proliferative diabetic retinopathy (PDR). Patients with PDR had a significantly longer duration of diabetes and worse glycemic control. There was a higher frequency of diabetic nephropathy in the PDR group, but only 13 patients out of 23 with PDR had nephropathy. The retinopathy progressed to high risk PDR two years after successful kidney-pancreas transplantation in one patient. CONCLUSIONS: In patients with type 1 diabetes mellitus, small hard drusen may be the initial manifestation of diabetic retinopathy. Risk factors for progression to PDR were duration of diabetic and poor glycemic control. Nephropathy was more prevalent in patients with PDR, but a significant group of PDR patients did not have demonstrable nephropathy.

Historia natural de retinopatía diabética en un estudio a largo plazo en pacientes con diabetes tipo 1. Factores de riesgo para progresión a enfermedad proliferante / Natural history of diabetic retinopathy in a retrospective cohort of type 1 diabetics

Background: Diabetic retinopathy is one of the most common causes of blindness among adults. Aim: To report the natural history of diabetic retinopathy among Chilean patients with type 1 diabetes followed for a mean of 18 years. Material and methods: Retrospective review of medical records of 39 patients aged 26 to 70 years, (20 females, 78 eyes) with type 1 diabetes controlled by the same ophthalmologist from 1971 to 2008. A questionnaire was sent to each patient and their treating physician to request information about the evolution of the disease and metabolic control. Results: The questionnaire was answered by 24 patients (62 percent) and 21 attending physicians (54 percent). Small hard drusen were observed in 25 patients (64 percent). In 12 cases the drusen were detected before the development of any type of retinopathy. Eleven women became pregnant and retinopathy progressed in four of them. Twently three patients (59 percent) developed proliferative diabetic retinopathy (PDR). Patients with PDR had a significantly longer duration of diabetes and worse glycemic control. There was a higher frequency of diabetic nephropathy in the PDR group, but only 13 patients out of 23 with PDR had nephropathy. The retinopathy progressed to high risk PDR two years after successful kidney-pancreas transplantation in one patient. Conclusions. In patients with type 1 diabetes mellitus, small hard drusen may be the initial manifestation of diabetic retinopathy. Risk factors for progression to PDR were duration of diabetic and poor glycemic control. Nephropathy was more prevalent in patients with PDR, but a significant group of PDR patients did not have demonstrable nephropathy (RevMéd Chile 2009; 137:1145-52).