# Biomaterials for Ophthalmic Applications
## 3 Concluding Remarks and Future Perspectives  
The eye is a complex organ composed of a container with three membranes and different transparent elements. As we age, the eye, similarly to every other organ in the human body, suffers changes, leading to a deterioration of vision [1]. Biomaterials try to compensate for vision loss which may or may not be related to age. Contact lenses, composed of several polymers are produced in industrial quantities [27]. The introduction of multipurpose solutions allows for the cleaning and disinfection of lenses with a single solution, also allowing for better patient compliance [33]. Intraocular lenses are introduced into the eye to replace the clouded lens in cataract [1]. They can be composed of acrylic compounds or silicone elastomers and are kept inside the capsular bag with haptics [63]. Artificial tears are used for dry eyes [75], which can be used as eye drops, gel or ointment [81]. Artificial tears are composed of a thickening agent, osmoprotectant, antioxidant, preservative (except in single dose form), buffers, excipients, electrolytes and lipid supplements [8,79]. Inays compensate for the loss in amplitude for the accommodation of presbyopia [9]. Vitreous body liquefies with age and can lead to pathological situations that require its replacement; however, the ideal substitute still does not exist and efforts should be taken to remedy this [13]. Different vitreous substitutes are used, in the form of gas or liquid [86], but the most promising for the future are those in hydrogels [12].  
Today, contact lenses are increasingly seen as a tool for specific ophthalmic treatments that require the delivery of a drug to the eye. The low bioavailability of common ophthalmic treatments, such as eye drops, is a concern in delivering effective treatments. Therefore, practitioners rely on new lenses to be developed to improve these treatments. This is of scientific interest; however, more should be done to facilitate their practical application. This can include clinical trials or the practicality of manufacturing.  
The intraocular application of hydrogels may lead to significant advances in improving their clinical application. Intravitreal drug delivery systems should be injectable and permit controlled drug release over several weeks or months. After complete drug release, the hydrogel should degrade without significant swelling. Similar requirements are imposed on hydrogel-based vitreous substitutes; however, these materials must be fully transparent  
Figure 2: Tissue engineering applied to cell and tissue manufacture and delivery. Cells are collected and harvested in order to perform expansion and differentiation. Cells and bioengineered scaffolds are then assembled to be able to be transplanted on the patient.  
and mechanically stable during the entire application period; therefore, research is needed to achieve such results.  
Biomaterials have been demonstrated to be highly beneficial in their role in solving ophthalmic conditions in many studies. Advances have been made in recent years, particularly in terms of smart or stimuli-responsive hydrogels. However, many of these formulations are not commercially available, mainly because many of them have yet to undergo clinical trials. This would be a vital step in improving the quality of life of patients.  
With an ageing population, eye diseases are becoming more widespread. Biomaterials have contributed to numerous medical devices for the restoration of eyesight, thereby improving many patients' quality of life. Therefore, biomaterials, tissue engineering and regenerative medicine are becoming increasingly important to advances in ophthalmology and optometry. However, more research is needed to improve the treatment of severe, vision-threatening diseases.  
This research received no external funding.  
Not applicable.  
The author declares no conflict of interest.