Embryology can be described as the study of growth and development of different organs in the human body (Sant, 2008). It usually explains several facts in the gross anatomy like relations and positions of various organs and the cellular blood supply. According to Sant (2008), embryology usually plays a significant role in helping individuals understand and diagnose the congenital anomalies. The knowledge of embryology is also critical to the health care providers in the process of offering a therapeutic response to the patients. Other aspects of embryology like gametogenesis, fertilization are essential in comprehension of concepts that causes infertility. On the other hand, the knowledge about congenital anomalies and aspects that cause them can be significant in preventing the prevalence of anomalies. The knowledge of embryology can also be utilized in the explanation of the development of the eye. This paper critically examines the embryology of the eye, the defects and the ethical issues about embryology.
The embryonal and the fetal development of the human eye usually entails a series of sequential events that starts with the fertilization of the ovum. The embryonic development of the eye usually takes place 22 days after the conception when the optic sulci forms in the neural fold (Heegaard & Grossniklaus, 2015). The embryology of the eye is usually characterized by the expression of the eye field transcription facts. These structures usually regulate the development of the eye structure that develops from neuroectoderm. This part is usually located on the surface of the ectoderm and the mesenchyme. When the neural tube is closed, the optic sulci transforms and become the optic vesicles. This transformation usually leads to the formation of the hemispherical extensions at the sides of the forebrains vesicle. The continuity in the neural tube is usually made of neuroedermal cells.
After one month, the optic vessels usually approach the surface ectoderm that induces the formation of the lens placodes that is folded back leading to the formation of two lens vesicles. On the other hand, the growth of the cells at the optic vesicles causes the folding inwards of the anterior parts of the vesicle hence the formation of the optic cup.
Heegaard and Grossniklaus (2015) discuss that in the second month of the interior part of the optic cup differentiates and forms the posterior iris epithelium while the interior part develops the neural sensory retina and the ciliary epithelium. The retinal pigment epithelium (RPE) usually develops from the outer layer of the optic cup and melanogenesis begins at week six. In the third month, the layers of the larger vessels start to develop, and the process continues to the subsequent months (Heegaard & Grossniklaus, 2015).
The optic nerves are also developed from the optic stalk where there is the connection with the forebrain. By the end of the seventh week, the optics discs usually develop to form the hyaloid artery that is usually surrounded by the axons that arise from the ganglion cells. By the time it reaches a year the disc is usually developed to 95% (Heegaard & Grossniklaus, 2015).
Ethical issues related to Embryology
Ethics is an integral part of the practitioner in the field of medicine. It is not an optional aspect, and every researcher must comply with the set code of ethics that informs their operations. The issue of embryology has sparked opinions from different critics in the medical department. The aspect of human cell research a moral dilemma for the medical practitioners since they have to choose between the obligation of prevention and alleviation of suffering or the duty to respect the human. To obtain the human cells sometimes the pathologists have to destroy the human body that poses a moral issue. However, conducting research on these cells is significant because it can lead to the development and the discovery that would curb the suffering of most individuals. Therefore, the biologists usually experience significant ethical dilemma when it comes to the source of the embryonic cells to be used in the research.
According to the Human and Fertilization and Embryology Act of 1990, it has been stipulated that there should be the code of ethics and practice that will be frequently updated to regulate the medicine research (Carr, 2015). Furthermore, it is a criminal offense for the practitioners in the field of medicine to be involved in the creation of embryo without permission from HFE. However, there are some cases that have been reported where the researchers in medicine discipline still engaged in the illegal creation of embryos, especially for fertilization.
This aspect has been considered a violation of the code of ethics especially in the practice of medicine. The issue of consent regarding retrieval of gametes and the use of embryos. Carr (2015) has argued that some medical practitioners obtain the gametes from another human being without informing them of the purpose they are going to use the collected. Some of them have gone to an extent of misleading the donors that it is for research purpose yet they are using them for developing of embryos (Carr, 2015). This aspect is considered as a breach of the ethical standards that guides the medical practitioners, and it is punishable by law. Therefore, it is an obligation of the medical researcher to obtain informed consent from the individuals they are obtaining these gametes. This strategy will ensure conformity to the ethical standards and transparency in the medical research. Furthermore, it is a legal requirement that will make them avoid violating the existing policies.
Heterochromia Eye Mutation
This condition is an eye mutation defect that is usually associated with eye color. Heterochromia can occur in three categories. Firstly, it is the complete heterochromia whereby each of the eyes has different colors. The second type is sectoral whereby contrasting colors may occur in the iris. The third type is central whereby various colors are reflected from the iris. This defect is usually caused by Waardenburg Syndrome whereby modified genes prevent the traveling of melanocyte to any part of the body particularly in embryos. The melanocyte is responsible for color pigment referred to as melanin. If it fails to transfer the melanin in the eyes or if only a few succeed to travel, one can have blue eyes (Khanal et al., n.d). The defect can also be caused by chimerism that is the fusing of two eggs to give rise to an embryo with one blue eye and one brown eye. This condition may affect the embryo in the future in that at a certain age; the child may feel different from the rest hence lowering his or her self-esteem. Fellow kids may intimidate him or her because of different eye color. Additionally, it is unfortunate that the embryo may pass the same defects to its offspring’s as it is genetic. Consequently, the defect will run in the family even in the future.
Drosophila Eye Defect
This condition is another eye defect caused by the failure of the fat facet, a gene responsible for cell interaction. Fat facet plays a key role in preventing certain cells in the embryo’s developing eye from being photoreceptors. Hence, when the fat does not convert the protein into the required form, then the embryos’ eye becomes photophobic and is mostly affected by light. The problem is mostly common to people with albinism disorder. The future consequences of this condition are that the person will need to seek medical attention to prevent further damage. People with this defect are usually photophobic and cannot withstand sunlight. Hence, they may need to ware classes that may cost them more medical expenditure compared to those that do not suffer from this problem. Additionally, the person may suffer as he or she may not be able to use gadgets that have a lot of light for long periods. Gadgets such as computers and some phones may affect their eyes, and this may disrupt their normal life in this digital era.
Red hair Defect of The Eye
This is a mutation defect that occurs in an embryo’s eye when several mutations occur in the melanocortin 1receptor. Pheomelanin is responsible for the red pigmentation of the red hair. The defect is in most cases inherited from both parents. As a matter of fact, most people may be carrying the red hair defect than those that have them physically. Furthermore, people with red-hair are most likely to be lighter in skin pigmentation compared to those without. People with red hair become more sensitive to thermal pain (Catania, 2010). This situation is as a result of the red-hair being a mutation of a receptor hormone that only can respond to melanocyte hormone and endorphins (Catania, 2010). The future effect of this defect is a condition known as endometriosis. This is a condition that affects the females. According to Guidice et al., (2012), women with red hair are likely to suffer from endometriosis that is characterized by the growth of tissue outside the uterus and is usually hurting. Additionally, persons with red hair defect usually have a lighter skin than others. This condition puts them at a higher risk of suffering from cancer due to increased radiation. Besides, people with red hair are likely to suffer from skin diseases and complications.
Possible Cures for Mutation
For heterochromia mutation, a contact lens can be used to darken or lighten the eyes so that they can appear normal. Additionally, if the person’s eyes have different colors, lens with different colors may be used to make things normal. For Drosophila eye defects, gene engineers can manipulate the phenotype by cell genes. There is a wide range of elements that can help to manipulate unique tissues and other cells. Overexpression strains can be acquired from stock avenues while others can be regenerated. Manipulation of genes for people with Drosophila defect may be used to improve the condition hence preventing future generations from suffering the same. On the other hand, Red hair defects could be solved by avoiding marriage partners who have this defect. Those that have the defect physically are likely to pass it more to their offspring. Genetic engineers have also gone ahead to manipulate the genes and use of test-tube babies of those with red hair so as to help reduce the risk.
In conclusion, the eye undergoes several stages before it becomes fully functional. This development that starts developing twenty-two days after fertilization may be successful to the end or it may be disrupted by various mutations. If mutations occur, the infant should receive medical attention as soon as possible to avoid future complications. Furthermore, the genetic engineers should continue making new discoveries on these defects help the future generations from suffering the same. On the other hand, medical practitioners should be vigilant while carrying out their duties. They need to apply medical ethics that are relevant to this field. For instance, some of the medical practitioners who collect specimen and embryos for research should let those involved be aware of what is happening. Failing to enquire even from these people is unethical and should not happen in such a noble profession. Paying practicing all the ethical rules outlined in the medical field will play a fundamental role in protecting human lives.