Minimum Corneal Diameter and Anterior Steep Axis Curvature Share the Same Meridian: A Novel Finding

PURPOSE

To define the external scleral sulcus (ESS) on a Scheimpflug image and use it for a morphometric analysis of corneal diameter (CD).

DESIGN

Retrospective, cross-sectional study of pediatric Asian-Indian eyes.

METHODS

One random eye of 353 subjects between 5 and 18 years underwent 25-scan Pentacam HR imaging. For all scans, densitometry values along the anterior corneal edge were recorded and differentiated. The peaks on the differentiated curve were chosen as the ESS points, and this distance between them was called CD. Vertical (vCD), maximum (maxCD), minimum (minCD) CD and their meridians were defined. Multiple regression models (MRMs) with CD and other Pentacam parameters were built to predict astigmatism and its axis, mean keratometry (Kmean), and Belin/Ambrósio enhanced ectasia display deviation (BAD-D). MRMs were validated using intraclass correlation coefficient (ICC). Estimated horizontal CD (hCD) was validated against digital caliper measurement using ICC.

RESULTS

The ICC (95% CI) between caliper and hCD was 0.96 (0.93, 0.97). MRM predictions (P < .001) used CD parameters, anterior chamber depth, corneal volume and distance from the corneal thinnest location to apex. These predictions achieved an ICC of 0.34 (0.18, 0.46), 0.82 (0.78, 0.86), 0.87 (0.84, 0.89), and 0.81 (0.76, 0.84), respectively. The astigmatism axis prediction depended on the minCD and maxCD meridians. Its within-subject SD (4.97°) was less than 2 consecutive Pentacam scan angles (7.2°).

CONCLUSIONS

The CD metric strongly correlated with the astigmatism axis, keratometry, and BAD-D. Its spatial description may be significant in corneal treatment planning and disease diagnoses.

Distinct gene expression profiles underlie morphological and etiological differences in pediatric cataracts

Purpose

Pediatric cataract is a major cause of preventable childhood blindness worldwide. Although genetic mutations or infections have been described in patients, the mechanistic basis of human cataract development remains poorly understood. Therefore, gene expression of structural, developmental, profibrotic, and transcription factors in phenotypically and etiologically distinct forms of pediatric cataracts were evaluated.

Methods

This cross-sectional study included 89 pediatric cataract subjects subtyped into 1) prenatal infectious (cytomegalovirus, rubella, and combined cytomegalovirus with rubella infection), 2) prenatal non-infectious, 3) posterior capsular anomalies, 4) postnatal, 5) traumatic, and 6) secondary, and compared to clear, non-cataractous material of eyes with the subluxated lenses. Expression of lens structure-related genes (Aqp-0, HspA4/Hsp70, CrygC), transcription factors (Tdrd7, FoxE3, Maf, Pitx 3) and profibrotic genes (Tgfβ, Bmp7, αSmA, vimentin) in surgically extracted cataract lens material were studied and correlated clinically.

Results

In cataract material, the lens-related gene expression profiles were uniquely associated with phenotype/etiology of different cataracts. Postnatal cataracts showed a significantly altered FoxE3 expression. Low levels of Tdrd7 expression correlated with posterior subcapsular opacity, whereas CrygC correlated significantly with anterior capsular ruptures. The expression of Aqp0 and Maf was elevated in infectious cataracts, particularly in CMV infections, compared to other cataract subtypes. Tgfβ showed significantly low expression in various cataract subtypes, whereas vimentin had elevated gene expression in infectious and prenatal cataracts.

Conclusion

A significant association between lens gene expression patterns in phenotypically and etiologically distinct subtypes of pediatric cataracts suggests regulatory mechanisms in cataractogenesis. The data reveal that cataract formation and presentation is a consequence of altered expression of a complex network of genes.

Surgical technique for the management of corneal perforation in brittle cornea

Brittle cornea syndrome is among the few special scenarios in ophthalmology that are a nightmare not only for the operating surgeon but also for the patient. Here, the thin and fragile corneas are unable to maintain the shape and structural integrity of the globe and are more prone to minor traumatic or spontaneous corneal perforations. Suturing a brittle cornea and closure of the corneal perforation in a brittle cornea are very challenging requiring the utmost care and special precautions. If proper measures are not taken during the surgery, it may be difficult to salvage the eye. Hence, it is imperative to diagnose appropriately, suture effectively, taking necessary preventive measures in salvaging these corneas. This manuscript aims at providing tips for handling brittle corneal perforations. It will also discuss the problems encountered during surgery, highlight the suturing techniques that can be customized, and finally give an insight into postoperative care.

Knobloch Syndrome in Siblings with Posterior Fossa Malformations Along with Cerebellar Midline Cleft Abnormality Caused by Biallelic COL18A1 Mutation: Case-Based Review

Knobloch syndrome (KS) is an autosomal recessive disorder caused by biallelic pathogenic variants in COL18A1 . KS clinically manifests with the typical eye findings (high myopia, vitreoretinal degeneration, retinal detachment, and lens subluxation), variable neurological findings (occipital encephalocele, polymicrogyria, cerebellar malformations, epilepsy, and intellectual disability), and the other uncommon clinical manifestations. Literature review of all KS patients (source PubMed) was done with special reference to cerebellar abnormalities. Here, we report two siblings with typical KS with posterior fossa malformations and novel cerebellar midline cleft abnormality analyzed by whole exome sequencing. Known pathogenic homozygous variant c.2908C > T; (p.Arg970Ter) in exon 26 of COL18A1 was found as a cause for KS. These two siblings presented with early-onset severe ocular manifestations, facial dysmorphism, and variable central nervous system manifestations along with novel cerebellar midline cleft abnormality. The presence or absence of structural brain malformations and genotypes does not absolutely predict cognitive functions in KS patients. However, the presence of posterior fossa abnormality may be predictive for the development of ataxia in later life and needs further studies.

Long-term outcome of custom toric intraocular lens for treating high astigmatism in case of cataract associated with pellucid marginal corneal degeneration

Pellucid marginal corneal degeneration (PMCD) is a progressive corneal ectasia that ultimately results in high regular astigmatism and correction of this astigmatism is always challenging. However, when a PMCD patient develops a cataract, it provides a golden opportunity to treat this coexisting astigmatism with toric intraocular lens (IOL) implantation. Regular toric IOLs would correct astigmatism only up to 6 diopters in the IOL plane but higher astigmatism would require customization of such IOLs. Our case report describes the long term outcomes of customized toric IOL to tackle this high astigmatism during cataract surgery in PMCD cases.

Unique corneal tomography features of allergic eye disease identified by OCT imaging and artificial intelligence

The purpose of this study was to assess unique corneal tomographic parameters of allergic eye disease (AED) using optical coherence tomography (OCT) and artificial intelligence (AI). A total of 57 eyes diagnosed with AED were included. The curvature and aberrations of the air-epithelium (A-E) and epithelium-Bowman's layer (E-B) interfaces were calculated. Random forest AI models were built combing this data with the parameters of healthy, forme fruste keratoconus (FFKC) and KC eyes. The AI models were cross-validated with 3-fold random sampling. Each model was limited to 10 trees. The AI model incorporating both A-E and E-B parameters provided the best classification of AED eyes (area under the curve = 0.958, sensitivity = 80.7%, specificity = 98.5%, precision = 88.2%). Further, the E-B interface parameters provided the highest information gain in the AI model. A few AED eyes (n = 9) had tomography parameters similar to FFKC and KC eyes and may be at risk of progression to KC.

Bosley-Salih-Alorainy syndrome in patients from India

Bi-allelic HOXA1 pathogenic variants clinically manifest as two distinct syndromes, Bosley-Salih-Alorainy syndrome (BSAS) and Athabascan brainstem dysgenesis syndrome, mainly reported in two different populations from Saudi Arabia and southwest North America, respectively. Here we report two siblings of Indian origin with BSAS phenotype caused by a novel homozygous exon 2 HOXA1 pathogenic variants.

Dopamine levels in human tear fluid

Purpose

To determine the levels of dopamine in tear fluid and demonstrate the use of tear fluid as a non-invasive source for dopamine measurements in humans.

Methods

The study cohort included 30 clinically healthy individuals without any pre-existing ocular or systemic conditions. Matched tear fluid (using Schirmer's strips and capillary tubes) and plasma were collected from the subjects. Dopamine levels were evaluated using direct competitive chemiluminescent enzyme-linked immunosorbent assay (ELISA), dopamine kit (Cloud Clone Corp, TX, USA).

Results

Significantly higher dopamine levels were found in the tear fluid compared to plasma in the study subjects. The level of dopamine was 97.2 ± 11.80 pg/ml (mean ± SEM), 279 ± 14.8 pg/ml (mean ± SEM), and 470.4 ± 37.64 pg/ml (mean ± SEM) in the plasma and in the tears collected using Schirmer's strips and capillary tubes, respectively.

Conclusion

Dopamine was detectable in all the tear fluid samples tested and was also found to be at a higher concentration than in plasma samples. Tear fluid can be used as a non-invasive sample source to monitor dopamine levels.

Corneal staining during cataract surgery: Natural course, ASOCT features, and preventive measures

We report the natural course of the accidental injection of trypan blue into the corneal stroma while performing a routine cataract surgery by a resident during a training session. The corneal staining resolved with conservative medical treatment over 7 weeks. This case describes the anterior segment optical coherence tomography (ASOCT) features of corneal staining. It emphasizes on the relatively benign nature of this dye and the follow-up course. Causes that may be responsible for this untoward complication are highlighted with the necessary preventive measures that need to be taken care are also discussed.

A Prospective OCT Study of Rubella Retinopathy

PURPOSE

To analyze rubella retinopathy qualitatively and quantitatively in children diagnosed with congenital rubella syndrome (CRS) using a handheld spectral-domain (SD) OCT device.

DESIGN

Prospective, cross-sectional, nonrandomized, comparative observational study in a tertiary eye care center in south India.

PARTICIPANTS

Cases comprised 24 eyes of 13 children diagnosed with CRS based on seropositivity with rubella retinopathy. Controls comprised 26 eyes of 13 age-matched healthy children with normal retina.

METHODS

All participants underwent retinal imaging with RetCam fundus photography (Natus Medical Inc, Pleasanton, CA) and handheld SD OCT (Bioptigen, Inc., Durham, NC). The SD OCT images of both cases and controls were segmented. Retinal and choroid thickness parameters were computed.

MAIN OUTCOME MEASURES

Qualitative and quantitative changes were observed in SD OCT images of rubella retinopathy compared with those from controls.

RESULTS

Characteristic salt-and-pepper appearance was observed on fundus photography in children with rubella compared with the healthy children. The appearance of fovea and retinal features such as foveal dip, external limiting membrane, inner segment-outer segment boundary, outer segment-retinal pigment epithelium boundary, and retinal pigment epithelium were significantly different (P < 0.05) in eyes with rubella retinopathy compared with healthy eyes Furthermore, eyes with rubella retinopathy exhibited significantly reduced central foveal thickness (P = 0.025), subfoveal outer retinal thickness (P = 0.01), and subfoveal choroid thickness (P = 0.007) compared with healthy eyes.

CONCLUSIONS

Distinct qualitative and quantitative differences were observed in the SD OCT images of eyes with rubella retinopathy compared with those from healthy eyes.

Comparative analysis of non-absorbable 10-0 nylon sutures with absorbable 10-0 Vicryl sutures in pediatric cataract surgery

Purpose:

The purpose of the study is to compare the efficiency as well as the rate and type of suture-related complications between 10-0 monofilament nylon (Aurolab Nylon Sutures, double arm, Aurolab) and 10-0 polyglactin 910 sutures (Vicryl, single arm, Aurolab) for pediatric cataract surgery.

Methods:

It is a prospective, comparative study performed in children who underwent surgery for congenital or developmental cataract from March 2013 to February 2016. Patients underwent suturing with either nylon or Vicryl in unilateral cases, but in most bilateral surgeries, one eye received Vicryl sutures while the other eye received nylon. The sutures were compared for their complications and the need for suture removal.

Results:

Forty-one children (72 eyes) were included in the study, of which 31 children (62 eyes) underwent bilateral surgery while 10 (10 eyes) underwent unilateral surgery. Sixty-four nylon sutures were placed in 32 children (34 eyes), of which 22 (34.4%) were removed due to suture-related complications, whereas 14 (19.7%) (P = 0.03) of the 71 Vicryl sutures placed in 32 children (38 eyes) needed suture removal at an average of 2.9 weeks with the earliest at 6 days postoperatively. The odds of Vicryl suture being removed was 0.42 times with respect to nylon. The most common reason encountered for suture removal in both the materials was sutures becoming loose (16.3%), followed by vascularization (14.1%), infiltration (1.5%), and opacification (4.4%).

Conclusion:

Absorbable suture such as 10-0 Vicryl is preferred over nonabsorbable suture 10-0 nylon for suturing incisions in pediatric cataract surgery, to avoid subjecting the child to repeated anesthesia.

Age and myopia associated optical coherence tomography of retina and choroid in pediatric eyes

Purpose:

To evaluate the association between retinal and choroidal thickness and volume along with choroidal vessel volume in children using optical coherence tomography (OCT) images.

Methods:

113 normal eyes of children ranging from 5-17 years of age were imaged with a clinical OCT scanner (Optovue Inc., Fremont, USA). The retina, choroid and choroidal vessels were automatically segmented with algorithms. Parameters evaluated were thickness and volume. Location specific analyses of thickness were also performed at a distance of 2.5 mm from foveal center. Multivariate analyses of variance were used to analyze the effect of age and myopia. Manual segmentation of the fovea and subfoveal choroid thickness was also performed to compare with the algorithm segmentation.

Results:

There was excellent agreement between manual and automatic segmentation (intra-class correlation of 0.95). Within the same eye, total retinal and choroid thickness of nasal and temporal location were significantly lower than the superior and inferior thickness (P < 0.0001). With age (P = 0.026) and myopia (P < 0.001), foveal thickness increased. Choroid volume, vessel volume and temporal choroid thickness increased with increasing myopia (P < 0.05). There was significant positive correlation between choroid volume and retinal volume (r = 0.62, P < 0.0001), choroid volume and vessel volume (r = 0.48, P < 0.0001), and with foveal thickness (r = 0.31, P = 0.009). Choroid vessel volume also showed significant positive correlations with the other metrics (P < 0.05).

Conclusion:

Retinal and choroidal structural features were quantified simultaneously from OCT images. Magnitude of myopia had a greater effect on retino-choroid features than age in children.

Surgical Outcome of Congenital Cataract in Eyes With Microcornea

PURPOSE

To report the intraoperative and postoperative outcomes of congenital cataract surgery in eyes with microcornea.

METHODS

In this retrospective, interventional, comparative case series, the authors reviewed 47 eyes of 26 children with microcornea and congenital cataract (21 bilateral and 5 unilateral) who underwent lens aspiration with primary posterior capsulectomy and anterior vitrectomy between 2008 and 2014 with a minimum follow-up period of 6 months. Demographic profiles and systemic and ocular features were documented. Intraoperative and postoperative complications were studied separately for bilateral and unilateral cases. Patients were also divided into two groups on the basis of their ages at surgery (early surgery group: 3 months or younger; late surgery group: older than 3 months) and postoperative complications were compared. Visual outcome was analyzed in those with a follow-up period of more than 1 year.

RESULTS

Early surgery was performed in 24 eyes of 13 patients (11 bilateral and 2 unilateral) and late surgery in 23 eyes of 13 patients (10 bilateral and 3 unilateral). Intraoperatively, all eyes had poor pupillary dilatation and 6 (12.8%) eyes needed iris hooks. Postoperatively, the most common early complication was transient corneal edema observed in 22 (46.8%) eyes (13 and 8 eyes in the early and late surgery groups, respectively). Late complications included visual axis opacification in 6 (12.76%) eyes (3 in each group), and secondary glaucoma in 5 (10.64%) eyes (2 and 3 eyes in the early and late surgery groups, respectively). Vision was normal for age in 18 (60%) of the bilateral cases with a follow-up period of more than 1 year.

CONCLUSIONS

Early surgical intervention for congenital cataract in eyes with microcornea can result in favorable outcomes with an acceptable rate of postoperative complications. [J Pediatr Ophthalmol Strabismus. 2018;55(1):30-36.].

Upbeat nystagmus in a 3.5-year-old boy

Upbeat nystagmus is usually a central vestibular nystagmus attributable to structural brainstem or cerebellar lesions. Adult-onset upbeat nystagmus calls for a thorough neurological evaluation. In children, however, it can occur as a transient phenomenon in healthy neonates or as a sensory form of nystagmus that usually transforms into horizontal nystagmus by 2 years of age. We report the case of 3.5-year-old boy with upbeat nystagmus. His ocular examination was within normal limits. Neurological evaluation was normal. Optical coherence tomography testing and Electroretinogram confirmed cone dysfunction. Over the next 6 months the upbeat nystagmus converted to horizontal nystagmus.

Fixation-linked nondissociated hypotropia: a report of 3 cases

Fixation-linked hypotropia, or hypotropic dissociated vertical deviation, is a rare but well-defined ocular motility disorder characterized by a slow downward drift of a poor-seeing eye when the other eye is fixating on a distant target. It can be successfully treated with a large recession or recession-resection of the inferior rectus muscle. We report 3 cases of fixation-linked nondissociated hypotropia with unilateral high myopia and amblyopia presenting with intermittent hypotropia of the worse-seeing eye when the dominant eye was fixating on a distant target and a hypertropia of the dominant eye when the poorer-seeing eye was made to fix. We discuss the surgical management of one of these patients.

Distal arthrogryposis type 5D with a novel ECEL1 gene mutation

Distal arthrogryposis syndromes (DAs) show wide clinical variability and overlapping clinical findings with the other DAs classified by Bamshad et al. [1996]. Most of the DAs are inherited as autosomal dominant disorders. DA type 5D is a subtype of DA type 5 inherited as autosomal recessive disorder, clinically characterized by congenital distal joint contractures, knee extension contractures, congenital hip dislocation, club foot, ptosis and other eye findings, furrowed tongue, and scoliosis. Here, we report on a family with clinical features of DA type 5D with novel mutations in the ECEL1 gene.

Synostotic anterior plagiocephaly: a cause of familial congenital superior oblique muscle palsy

Anterior plagiocephaly due to unicoronal craniosynostosis is commonly associated with an ipsilateral hypertropia and a contralateral head tilt. The ipsilateral superior oblique weakness has been attributed to the shortening of the orbital roof with retroplacement of the trochlea, and to heterotopic positioning of the vertical rectus muscles within the orbit. These anatomical aberrations may alter ocular rotations to mimic a true congenital superior oblique palsy. This paper describes two siblings with synostotic plagiocephaly and simulated superior oblique palsy with ocular torticollis successfully managed by strabismus surgery. Synostotic plagiocephaly should be included in the differential diagnosis of familial congenital superior oblique palsy.

Positional vertical opsoclonus: a transient phenomenon in normal healthy twins

Opsoclonus is characterized by rapid bursts of involuntary, multidirectional, saccades without an intersaccadic interval. Three types of opsoclonus that occur in infancy have been identified, 2 of which are associated with a systemic or neurologic condition. The third is a benign condition that occurs transiently in healthy neonates and preterm babies. We report a case of 2 healthy twins who presented with transient opsoclonus, which was confined only to the vertical plane and manifested only in a supine position. Opsoclonus disappeared when the cheek was tapped. These eye movements began at 3 months and completely resolved by 6 months of age.

Mutational screening of Indian families with hereditary congenital cataract

PURPOSE

To screen for pathogenic mutations in ten candidate genes in Indian families diagnosed with autosomal recessive and autosomal dominant cataracts.

METHODS

Families with two or more affected individuals with bilateral familial congenital/developmental cataract were ophthalmically evaluated, and blood samples were obtained. Genomic DNA extracted from the blood leukocytes was screened with PCR amplification of the exons and the flanking intronic regions of various genes selected for analysis. The amplified products were subjected to single strand conformation polymorphism (SSCP) analysis. The variants in SSCP analysis were subjected to bidirectional sequencing by automated methods.

RESULTS

We identified four novel sequence changes that cosegregated with the disease phenotype in each family and were absent in at least 50 ethnically matched unrelated normal controls. These changes include a homozygous missense change of c.649G>A (Val196Met) in GJA8/connexin 50 (Cx50) in a family with autosomal recessive cataract, two heterozygous missense changes, c.658C>T (Pro199Ser) in GJA8/Cx50 and c.589C>T (Pro197Ser) in GJA3/connexin 46 (Cx46) in two separate families with autosomal dominant cataract, and a silent change ( c.84G>A/p.Val28Val, predicted to result in the creation of a new potential branch point) in GJA8 one family with an autosomal dominant inheritance of cataract. Of the four novel mutations identified, three mutations, Val196Met (GJA8), Pro199Ser (GJA8), and Pro197Ser (GJA3), are predicted to be in the second extracellular domain of the respective connexin proteins.

CONCLUSIONS

Our report extends the mutation spectrum of connexin genes GJA8 and GJA3 and confirms that connexin genes are among the most frequently mutated genes in hereditary cataracts. Our results suggest that connexin gene (GJA8 and GJA3) mutations occur in approximately 10% (4/40 families) of families with congenital hereditary cataracts in a population from southern India.

Modification of screening criteria for retinopathy of prematurity in India and other middle-income countries

PURPOSE

To determine the gestational age and birth weight of premature babies who developed vision-threatening severe retinopathy of prematurity.

DESIGN

Prospective observational study of babies at risk of blindness due to retinopathy of prematurity.

METHODS

Data pertaining to all babies who underwent laser treatment or surgery for acute retinopathy of prematurity and those who had cicatricial retinopathy of prematurity were prospectively collected. The gestational age and birth weight were evaluated to establish screening criteria.

RESULTS

In 120 babies, the mean gestational age was 29.6 weeks (range 26 to 36 weeks). The birth weight of 115 babies ranged from 710 to 2000 g (mean 1254.5 g, SD 280.8). Birth weight was not available for five babies. Only one baby had a gestational age of >35 weeks.

CONCLUSIONS

Ocular morbidity related to retinopathy of prematurity was seen in bigger and more mature babies. This study provides a scientific basis for establishing screening criteria for retinopathy of prematurity in South India and other middle-income countries.