Demographics and histopathological characteristics of enucleated microphthalmic globes

Genetic and environmental factors contributing to anophthalmia and microphthalmia: Current understanding and future directions

Anophthalmia is defined as a complete absence of one eye or both the eyes, while microphthalmia represents the presence of a small eye within the orbit. The estimated birth prevalence for anophthalmia is approximately 3 per 100000 live births, and for microphthalmia, it is around 14 per 100000 live births. However, combined evidence suggests that the prevalence of these malformations could be as high as 30 per 100000 individuals. Microphthalmia is reported to occur in 3.2% to 11.2% of blind children. Anophthalmia and microphthalmia (A/M) are part of a phenotypic spectrum alongside ocular coloboma, hypothesized to share a common genetic basis. Both A/M can occur in isolation or as part of a syndrome. Their complex etiology involves chromosomal aberrations, monogenic inheritance pattern, and the contribution of environmental factors such as gestational-acquired infections, maternal vitamin A deficiency (VAD), exposure to X-rays, solvent misuse, and thalidomide exposure. A/M exhibit significant clinical and genetic heterogeneity with over 90 genes identified so far. Familial cases of A/M have a complex genetic basis, including all Mendelian modes of inheritance, i.e., autosomal dominant, recessive, and X-linked. Most cases arise sporadically due to de novo mutations. Examining gene expression during eye development and the effects of various environmental variables will help us better understand the phenotypic heterogeneity found in A/M, leading to more effective diagnosis and management strategies. The present review focuses on key genetic factors, developmental abnormalities, and environmental modifiers linked with A/M. It also emphasizes at potential research areas including multiomic methods and disease modeling with induced pluripotent stem cell technologies, which aim to create innovative treatment options.

Cataract Surgery in Eyes with Microphthalmos and/or Uveal Coloboma

INTRODUCTION

Cataract may cause severe visual impairment in eyes with microphthalmos (MO) and uveal coloboma (UC). Despite their similarities, distinguishing between these conditions is crucial for cataract surgery. We aimed to compare complications, nucleus hardness, surgical strategies, and outcomes of cataract surgery between MO and UC.

METHODS

This retrospective comparative study included 19 eyes with MO and 20 with UC. Preoperative, intraoperative, and postoperative data of eyes that underwent cataract surgery were analysed.

RESULTS

MO eyes had lower high-hardness nucleus rates (p = 0.002) than UC. The most common preoperative complications in the MO and UC groups were glaucoma (37.5%) and retinal detachment (15.4%), respectively. No significant differences in the phacoemulsification (p = 0.45) or intraocular lens implantation (p > 0.99) rates between the two groups. Extracapsular cataract extraction was performed in five eyes (25%), and posterior capsular rupture was the most common surgical complication (15%) in the UC group. Combined surgery was mainly used to deal with high or unstable intraocular pressure (IOP; 77%) in the MO group versus posterior pars plana vitrectomy (85.71%) in the UC group to treat vitreoretinal pathologies. Corrected distance visual acuity was significantly improved in both MO (p = 0.0005) and UC (p < 0.001) groups, while IOP was decreased (p = 0.03) in the MO group.

CONCLUSION

Eyes with MO and UC exhibited distinct cataract grades and complications, necessitating varied surgical strategies; while cataract surgery has proven to be effective in improving the visual acuity in both groups. Our findings hold significant value for guiding clinical treatment decision-making.

An Overview of Zika Virus and Zika Virus Induced Neuropathies

Flaviviruses pose a major public health concern across the globe. Among them, Zika virus (ZIKV) is an emerging and reemerging arthropod-borne flavivirus that has become a major international public health problem following multiple large outbreaks over the past two decades. The majority of infections caused by ZIKV exhibit mild symptoms. However, the virus has been found to be associated with a variety of congenital neural abnormalities, including microcephaly in children and Guillain-Barre syndrome in adults. The exact prediction of the potential of ZIKV transmission is still enigmatic and underlines the significance of routine detection of the virus in suspected areas. ZIKV transmission from mother to fetus (including fetal abnormalities), viral presence in immune-privileged areas, and sexual transmission demonstrate the challenges in understanding the factors governing viral persistence and pathogenesis. This review illustrates the transmission patterns, epidemiology, control strategies (through vaccines, antivirals, and vectors), oncolytic aspects, molecular insights into neuro-immunopathogenesis, and other neuropathies caused by ZIKV. Additionally, we summarize in vivo and in vitro models that could provide an important platform to study ZIKV pathogenesis and the underlying governing cellular and molecular mechanisms.

Fertility and pregnancy in chronic myeloid leukemia: real-world experience from an Indian tertiary care institution

Chronic myeloid leukemia (CML) management during pregnancy is challenging. In this retrospective study, hospital records of CML patients treated between 2000 and 2021 were screened to identify patients who tried to conceive/got pregnant (planned and unplanned) on TKIs (tyrosine kinase inhibitors)/were pregnant at CML onset/fathered a child. We found ninety-three pregnancies involving thirty-three women and thirty-eight men, and they were analyzed for the pregnancy outcomes and the strategies utilized for CML management during pregnancy and the pre-conception period. There were two women and four men with primary infertility and five women with secondary infertility. TKIs were discontinued before conception in four planned pregnancies and at the time of recognition of pregnancy in unplanned pregnancies (n = 21). Unplanned pregnancy outcomes were two miscarriages, eight elective terminations, and eleven live births. Planned pregnancies led to four healthy babies. Outcomes of pregnancies at CML onset (n = 17) were six live births, one stillbirth, five elective terminations, and five abortions. Except for one child with congenital micro-ophthalmia, no other child born to the women on TKI had any malformations. Thirty-eight men fathered 51 healthy children. All but two patients (one planned and one unplanned pregnancy) lost their hematological responses during pregnancy and gained their previous best response after restarting TKI. In women who were pregnant at CML onset, complete cytological remission (CCYR) was achieved between 7 and 24 months (median:14 months) after starting TKI. During pregnancy, intermittent hydroxyurea ± TKI (in the second and third trimesters) was used to keep WBCs less than 30,000/mm3. Outcomes of pregnancies in CML patients can be optimized with our approach. TKIs (Imatinib and Nilotinib) can be safely used in the second and third trimesters. Delayed initiation or interruption of TKI during pregnancy does not negatively affect response to TKIs.

Pathogenesis and Manifestations of Zika Virus-Associated Ocular Diseases

Zika virus (ZIKV) is mosquito-borne flavivirus that caused a significant public health concern in French Polynesia and South America. The two major complications that gained the most media attention during the ZIKV outbreak were Guillain-Barré syndrome (GBS) and microcephaly in newborn infants. The two modes of ZIKV transmission are the vector-borne and non-vector borne modes of transmission. Aedes aegypti and Aedes albopictus are the most important vectors of ZIKV. ZIKV binds to surface receptors on permissive cells that support infection and replication, such as neural progenitor cells, dendritic cells, dermal fibroblasts, retinal pigment epithelial cells, endothelial cells, macrophages, epidermal keratinocytes, and trophoblasts to cause infection. The innate immune response to ZIKV infection is mediated by interferons and natural killer cells, whereas the adaptive immune response is mediated by CD8⁺T cells, Th1 cells, and neutralizing antibodies. The non-structural proteins of ZIKV, such as non-structural protein 5, are involved in the evasion of the host's immune defense mechanisms. Ocular manifestations of ZIKV arise from the virus' ability to cross both the blood-brain barrier and blood-retinal barrier, as well as the blood-aqueous barrier. Most notably, this results in the development of GBS, a rare neurological complication in acute ZIKV infection. This can yield ocular symptoms and signs. Additionally, infants to whom ZIKV is transmitted congenitally develop congenital Zika syndrome (CZS). The ocular manifestations are widely variable, and include nonpurulent conjunctivitis, anterior uveitis, keratitis, trabeculitis, congenital glaucoma, microphthalmia, hypoplastic optic disc, and optic nerve pallor. There are currently no FDA approved therapeutic agents for treating ZIKV infections and, as such, a meticulous ocular examination is an important aspect of the diagnosis. This review utilized several published articles regarding the ocular findings of ZIKV, antiviral immune responses to ZIKV infection, and the pathogenesis of ocular manifestations in individuals with ZIKV infection. This review summarizes the current knowledge on the viral immunology of ZIKV, interactions between ZIKV and the host's immune defense mechanism, pathological mechanisms, as well as anterior and posterior segment findings associated with ZIKV infection.