Ocular Prosthesis: Introduction, Fabrication Techniques and Wearer's Complications

The loss of an eye through accident, disease or from congenital disorders is a significant life event that impacts on a person's self-image, confidence and wellbeing. It warrants on the part of the affected person to undergo perceptual adjustments because of the loss of binocular cues to depth and the reduction in visual field on the affected side. While the prosthetic eye comes as a boon for cosmetic rehabilitation, the person also would have to make a behavioral adaptation because they need time and training for wearing and maintaining the prosthesis.

A prosthetic eye is designed to restore the appearance of the eyeball and partly the function of the eyelids. The term 'ocular prosthesis' is used throughout this writing, however, other terms like 'prosthetic eye' and 'artificial eye' can also be used synonymously.

The absence of ocular tissue in the orbit is considered as anophthalmia, which can be both congenital and surgical. The anophthalmic eye socket resulting from enucleation after trauma, painful blind eye, endophthalmitis, intraocular malignancy or phthisis bulbi due to various causes may lead to several social, familial and psychiatric problems. After surgically removing the eyeball, an artificial eye is placed instead in order to improve the aesthetic values of the disfigured face. Therefore, ocular prosthesis is a form of prosthetic device that is positioned in orbit with or without replacement of ocular tissues to alleviate the cosmetic appearance of the face. A disease and its treatment do have their own inherent qualities that bring about a range of consequences including changes in psychosocial behavior.

World History of Ocular Prosthesis

We have seen vintage old-movies scenes where pirates patch one eye to obscure facial disfigurement as a result of unilateral eye loss. Due to physical threats, wild animal encounters and war, losing one eye and accepting it with just a fabric or leather patch had become a lifestyle. The first report of ocular prosthesis, however, dates back to 2900-2800 BC in Iran and was presumably made up of gold plated bitumen paste with central iris engravings, with a diameter around 2.5 cm (Sajjadi, 2007) Egyptians and Roman priests made prosthesis by painting the clay which the Greek termed Ekblebharon (worn in front of the eyelid)(Chalian VA, Drane JB, 1971).

Ambrose Pare, a Frenchman, is believed to be the first person who devised an in-socket prosthetic eye in the sixteenth century (E, 1968). Pare was also assumed to be the person to design hypoblepharae (prosthetics worn inside the eyelid)(Chalian VA, Drane JB, 1971). During those times, prosthetic eyes were primarily made up of metals, woods, ivory and glass. For a brief period of the 1700s, Paris became the hub for manufacturing prosthetic eyes where Auguste Boissenneu made thin enamel shells on order which could be worn over shrunken eyes. A German doctor Friedrich Phillip Ritterich did not like the overpricing of the prosthetics in Paris and hence started to make cheaper ones in Germany though the crude materials had to be brought from Paris. He encouraged German glassblowing industries to make artificial eyes and established free eye glass service at his Leipzig Eye Institute.

The quick adaptation of technology by the Germans made Germany a new hub for prosthetic makers in the mid 19th century (Smith BC, Della Rocca RC). The year 1880 saw 'reform eyes' − a hollow glass eye with round edges, developed by Dutch ophthalmologist Hermann Snellen. Germany became the largest exporter of stock eyeglasses made from Cryolite glasses in the 1900s. The field of ocular prosthesis revolutionized later in 1930s after the introduction of PMMA materials by Imperial Chemical Industries (ICI) under various market names: Plexiglas, Lucite, Perspex, etc.(Kollewe J). At this time the prosthetic eye was clearly falling under the practice scope of dental technicians because molding and curing was quite similar to that of vulcanite rubber essential for dentures. Fritz W. Jardon, a German dental technician who migrated to USA and joined American Optical Company in 1930s; this made a clear way to successfully adopt mass production of high-finished PMMA prosthetics with worldwide supply capacity. Lately, silicone prosthetics have arrived in the market but has not replaced PMMA yet. 

As has been discussed, dental technicians felt the need that since making ocular prosthesis was under their professional arena, they should be further expanding and strengthening their expertise in this particular subject. This led to the formation of a new discipline called maxillofacial prosthetics, that enabled the dental professionals to legally and openly address the people by ocular prosthetic rehabilitation. At some point, role of optometrists seemed to be caring eyes only until they stopped to see. The Americans reformulated the concept to encompass the ocular prosthetic division under 'ocularistry', a branch of ophthalmology, while the English ideology focused on dental technology until later. American Society of Ocularists (ASO) was established in 1957; they standardized the profession of ocularist with requirements of training and certificatio (N., 2006). Manufacturing process had now embraced many avant-garde approaches like computer aided designs, CNC technologies, photographic adaptations, etc.

     
Scenario of Ocular Prosthesis in Nepal

Similar to world history, the ocular prosthesis were, for a long time, made by dental professionals and these skill sets are largely claimed by maxillofacial prosthodontists. Major bulk of making ocular prosthesis is still in those hands. People's Dental College is the oldest dental college of Nepal and its faculty members have been involved in not only making but also in ocular prosthetic rehabilitative services. In the 2000s, many eye hospitals of Nepal started to offer stock fitting prosthetic eyes. They are available to public purchase from a few hundred to fifteen hundred Nepalese rupees. It was only in January 2012 AD that an Ocularist unit was established in an eye hospital for providing prosthetic services in Nepal (Adhikary R and Shrestha K, 2020) The pioneering endeavor was undertaken by Tilganga Institute of ophthalmology (TIO). Since then the unit is manned by a senior ophthalmic assistant Mr Kumar Shrestha, who was trained on ocular prosthetic procedures and fitting techniques. Eye health worker Sabita Chamling Rai also helps him in the unit as an adjunct. The unit has made and fitted over one thousand customized prosthetic eyes. Since TIO's ocular Oncology and oculoplastic department is nation's referring point for many ocular carcinomas and ocular disfigurement, it serves as the good feeder for the cases to the ocularist unit.

After about six years, Dhristi Eye Care System has also started its daily ocularist unit at Kalanki and occasionally (monthly or bimonthly) in Jhapa. The unit was first manned by optometrist Ravi Shankar Chaudhary, but has now recently left. Few other private clinics also offer prosthetic services in major cities of Nepal. Though the global ocular prosthesis has already witnessed state-of-the-art technologies in its design and fabrication, Nepal is still relying on manual or semi-manual techniques.

Anophthalmia

The absence of ocular tissue in the orbit is considered as anophthalmia. Congenital form of anophthalmia can be categorized into true anophthalmos where there is complete absence of ocular tissues and clinical anophthalmos where there are evidences of neuro-ectodermal tissues in histological sectioning (Verma and FitzPatrick, 2007). Since extreme microphthalmia also requires prosthetic rehabilitation, and is intermediary between anophthalmos and microphthalmos, we tend to keep it under the category of anophthalmia. Anophthalmia can also be an acquired condition due to trauma, phthisis bulbi, atrophic bulbi, contracted socket, staphyloma and surgical procedures like enucleation, evisceration and orbital exenteration (Raizada and Rani, 2007). Ocular prosthesis is a form of prosthetic device that is positioned in the orbit with or without replacement of ocular tissues to alleviate the cosmetic appearance of the face. 

The Anophthalmic Socket

Figure 1: The Anatomy of anophthalmic socket

The successful fitting of ocular prosthesis largely depends upon the status of anophthalmic socket, which is where the artificial eye rests upon the biological structures of the orbit. The integrity of the socket might also be disrupted due to unnatural physical insults or trauma. Above figure clearly outlines the structural environment of a normally expected anophthalmic socket with an implant in situ.

Types of Eye Removal Surgeries

Eye removal is mandated in certain circumstances like retinoblastoma, painful blind eye, trauma to mitigate sympathetic ophthalmitis, etc. It is also done in the black fungus infection, an uncommonly encountered post-COVID manifestation, to stop the spread of infection beyond orbit and hence to save life. Surgical removal of eyeball consists of three approaches:

a) Enucleation

The surgical technique that removes just the eyeball or globe leaving the conjunctiva, tenon's capsule, extraocular muscles and the stub of optic nerve in their own place is called enucleation. This is the most common eye removal surgery and is assumed to be also the oldest operation in the field of ophthalmology (Moshfegi, 2000). By the prosthetist's point of view, enucleation is superior in that they offer ample space for larger implants, and furnishes better cosmesis. It also has lesser risks for sympathetic ophthalmitis when compared to evisceration (P, Viswanathan; Mandeep S, Sagoo; Jane M, no date). Intraocular tumors, including retinoblastoma and uveal melanomas, have been the primary indication for enucleation.

b) Evisceration

The surgical procedure is called evisceration when only the viscera or intra-ocular contents of the eyeball is removed. That means uvea, retina, vitreous, lens are removed so that sclera will be left. The technique is simpler and less invasive than enucleation and it provides better motility of the ocular prosthesis and ensures stability of the anophthalmic socket (Chen, 2001). The major indications of evisceration have been painful blind dye due to endophthalmitis, corneal perforation and secondary glaucoma.

c) Orbital Exenteration

This is more of an extrusive surgical technique whereby all the intra-orbital contents, typically including the conjunctiva, globe, orbital fat, part or all of the lids and sometimes a portion of the bony orbit are removed leaving patients severely cosmetically disfigured. The esthetic rehabilitation cannot be fulfilled by ocular prosthesis alone. It warrants maxillofacial prosthesis. Hence, this most radical of procedures is reserved for patients with large, highly invasive orbital tumors which may have originated from within the orbit or from the surrounding orbital structures.

Implants and Conformers

The average volume of the eyeball is 6-7 ml and once the eyeball is removed, the volume should be substituted with intra-orbital implant and prosthesis. The characteristics of an ideal implant should be: 1) it should provide ample space to the fitting and motility of prosthesis 2) it should be stable enough to restore the intra-orbital integrity 3) there should be no risk of extrusion.

Implants are of two types according to the nature of their connection to the adjacent ocular tissues. Non-integrated orbital implants are mostly spherical and made up of PMMA or silicone material and are not directly attached to the extraocular muscles, whereas bio-integrated orbital implants are the ones that have connection points, holes or channels to facilitate the attachment of extraocular muscles. The connection renders a sort of ocular motility while in different gazes. Earlier forms of integrated implants were Iowa implants and Allen implants but now these are largely replaced by hydroxyapatite coral implants with porous surface that allows fibrovascular sheathing for better attachment. The central drill also would make a hole where a peg can be inserted whereby the peg constitutes the bridging component between implant and outer cosmetic prosthesis. This enabled increased ocular motility but, unfortunately, it was not without complications and obviously it needed extra surgical effort for drilling and putting up the peg. Other common integrated implants used in today's practice are porous polyethylene, aluminium oxide and bio-ceramic among others. In case the implant is not porous, it  is wrapped with donor sclera, preserved bovine pericardium,  human fascia lata or vicryl mesh in order to impart the biocompatibility.

Post-surgical conformers are put outside the conjunctival surface after an implant is inserted and sutured from the outside. The eye is then pressure-patched for 24-48 hours. These conformers are made up of silicone or clear PMMA materials. The aim of putting conformers are: 1) it preserves the fornices intact 2) it protects the conjunctival wound underneath and accelerates healing process thereby avoiding implant extrusion 3) it makes the space ample for future prosthetic fitting. Since conjunctival healing may bring about some form of contracture, there should be no delay in putting the new prosthesis before complications, like discharges, inflammation and socket contracture take place. Generally, a month of gap between enucleation surgery and prosthetic placement is expected.

Figure 2: Post-surgical conformer Right Eye

Eye Loss

Unilateral eye loss brings about having to change the ways you interact with the environment. This is because having only one eye functioning means your visual world shifts to the side of your seeing eye. Over the long run, perceptual adaptations virtually neglect the side of your non-seeing eye. So, you have to adjust your head i.e. turning the face towards the defective eye is a common occurrence because visual system tries to compensate the reduced visual field offered by a single eye. This may sometimes afflict people while trying to cross the busy road or driving.

Monocular vision also means that you have lost the cues for binocular depth perceptions. This limits a person from performing fine activities that demand sharp stereo-acuity, like needling. They are also deprived from enjoying 3D movies in theatres while their friends enjoy normal life unbeknownst to the fact that one of their friends cold not see what they could.  

Psychosocial Aspect and Quality of Life (QoL)

Losing an eye has a far-reaching impact on a person's life especially on how s/he feels about herself/himself and this will alter how s/he interacts with other people. A disease and its treatment do have their own inherent qualities that bring about a range of consequences including changes in psychosocial behavior (Zboralski et al., 2008). World Health Organization has defined a health as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity (Kelley, 2008). This widely talked about ‘well-being’ is linked with quality of life (QOL), which is now a global concept that encompasses mental, social and physical activities that could be affected negatively by disease and infirmity or positively by good physical and mental conditions (Zboralski et al., 2008). Since quality of life (QOL) carries a broader meaning, health related quality of life (HR QOL) has been used in health researches to represent QOL particularly affected by a health condition. So, this perceived well being gets affected once an eye is lost. Many studies have tried to quantify the quality of life with scores in order to easily analyze, compare and interpret them.

Eye loss is an event in life that does not only entail the physically absent eye. It does have a lot of psychosocial consequences as well. We can even arbitrarily check this status of anophthalmic patients by administering a quick Hospital Anxiety and Depression Score (HADS) questionnaire. Many people, particularly adolescents, fear the negative body image due to eye loss. This may, at times, severely limit their social activities, participation and overall development. 

As we come to know that the absence of orbital content makes the surrounding tissues hypo-functional and may become atrophied, individually fabricated prosthetic eye not only plays an important role in the functional restoration partially but also cosmetic enhancement in the appearance (Goiato, de Caxias and dos Santos, 2018).

Corneal Tattooing, Prosthetic Shell, and Prosthetic Eye

Corneal tattooing is a less invasive procedure which involves making micro-punctures on the scarred cornea and putting the shades of drawing ink in the anterior stroma to give matching color to the fellow eye. If the eye is of similar size then tattooing will fulfill the demand of cosmesis. However, if the size is smaller we have to go for a prosthetic shell or prosthetic eye. Corneal tattooing has a dual purpose: 1) esthetic: if the patient can't wear cosmetic contact lens the corneal scar should be painted black or blue with the tattoo 2) functional: the seeing eye can be sometimes photo-sensitive due to partial/complete aniridia or albinism where pupillary zone is peripherally blocked by the tattoo.

Figure 3: Corneal tattoo

Prosthetic shell is a thin prosthetic device that fits over a phthisical eye. The central thickness of such a shell is less than 1 mm. If the globe is still remaining but with small size and whitish cornea, then prosthetic shell might be a good indication since it widens the palpebral aperture by lifting the upper eyelid and obscures the corneal opacity.

Ocular prosthesis or simply prosthetic eye is a prosthetic device that helps to restore the orbital integrity in the absence of an eyeball. Ideal prosthesis not only fills the orbital area but also maintains the lid tonus and facilitates the circulation of tears. Indeed, ocular prosthesis is not recommended and used only for cosmesis, it has numerous functional and anatomic importance as well. It prevents the deformation of eyelids; it also imparts the fullness to the anophthalmic cavity preventing muscle atrophy. It constantly facilitates the right and healthy orientation of lacrimal flux and checks debris accretion. It is for this reason that the anophthalmic children be fitted with the prosthesis so that the facial symmetry is preserved for long as it allows normal growth and development of hard and soft tissues of the surrounding.

Procedures for Customized Ocular Prosthesis Fabrication

Generally fabrication of a customized ocular prosthesis consists of the following steps:

a) Impression: a plastic impression tray is placed in the anophthalmic socket where impression materials (mostly alginate powder) are injected through the central pipe after mixing in the water in approximately 1:1 ratio from the nozzle of a syringe. Alginate is an elastic, irreversible hydrocolloid impression material which quickly sets (in about less than a minute) to the contours of ocular surfaces beneath the eyelids. The impression is then taken out.

Figure 4: Re-usable impression trays

b) Wax conformer: The impression is put in a plastic cup and is poured over by alginate powder mixed with water as above. After it sets out, we can take out the impression by dissecting the elastic alginate. The void formed in the alginate material is then filled by pouring melted wax. After some time, the wax conforms to the interior contours of the alginate mold. The wax sphere has the matching contours with the ocular surfaces. Errors of impression can be corrected in this step and many adjustments can be done through wax conformers like ptosis, lid sagging, excessive gaps, etc.

Figure 5: Making wax conformer

c) Centration : After cooling, the wax sphere is separated out and further smoothened. It is inserted into the patient's socket and watched for the appropriate fit and centration of the pupil by a marker, with the patient in the standing position looking straight ahead and in a good lighting condition. The marker would signify the point where the iris button of closely matching color is centralized.

Figure 6: Iris centration

d) Two-part mold: The wax model creates an impression in the plaster of Paris (stone mould) put in the two-part metal mold. The hollow spherical zone is now filled with acrylic (methyl methacrylate powder) material and is put for polymerization either in the polymerizer or in the heating pressure cooker. In a few hours, white PMMA prosthesis is made with an iris.

Figure 7: two-part molds

e) Hand painting: PMMA prosthesis is inserted into the eye and looked for color discrepancies in natural light. Then color tainting is done with a hand brush with the addition of blood vessels with tiny red threads to give a more natural look. In some setting, the replica of iris is produced by digital imaging of the fellow eye.

Figure 8: Hand painting to match the color

f) Final layering with clear PMMA : The final stage consists of overlaying of clear PMMA through a process of polymerization over the semi-finished white PMMA prosthesis. It is done for a lustrous look and for a 3D appearance so as to give an illusion of virtual AC depth.  

Figure 9: before undergoing clear PMMA polymerization

Stock Prosthesis vs Custom made prosthesis

Stock prosthesis are the ready-to-use prosthesis manufactured in mass quantity with the general parameters, color and sizes. They are relatively cheap as production is made in large scale. But, it may not exactly match the iris color, size and shape of the fellow eye. It cannot be modified per the need of patients and the life span of stock prosthesis is generally 1-2 years. Since the fitting is not as par, there are obvious reasons why these prosthesis are full of post-fitting complications like inflammations, deposits, allergies, excessive discharges and non-tolerances.

Custom made prosthesis (CMP) is person-specific and it exactly matches the contours of ocular surface. Hence it allows for minimal movement to give a somewhat natural look unlike stock prosthesis. Complications are also minimal owing to the close alignment of the prosthesis to the underlying surface. If there is no void, there are less chances of accumulation of tears and debris that might form colonizing zones for infectious organisms. The durability of CMPS is about 7-10 years according to the handling behavior of the patients. It can be polished, resurfaced and adjusted as per needed. 

Common Complications associated with the wearing of ocular prosthesis

The common complications encountered by the patients while wearing a prosthetic eye can be shortly summarized as below:

 (a) Discharge

Discharge is probably the most common ocular problem faced by the prosthetic wearers. While it is less pronounced in comparison to those wearing stock prosthesis, the problem appears to rise as the prosthesis ages. The problem of discharge arises due to two factors: one; mechanical irritation and two; infection. White, ropy discharge is an indication of allergy due to the mechanical friction against the ocular surfaces. We can observe the giant papillary reactions at the palpebral conjunctiva, more conspicuously in the upper palpebra. A combination of corticosteroid (prednisolone or dexamethasone) with longer dose of sodium cromoglycate is the standard mode of treatment with the regimens depending upon the severity. Yellow muco-purulent discharge is, on the other hand, an indication of bacterial infection.

 (b) Discomfort

Another commonly seen problem with the prosthetic wearers is the ocular discomfort with the wear. The discomfort generally arises from two factors: either there is a problem in the prosthetic eye itself like scratches, rough deposits, chips broken out, sharp edges, faded coats, etc., or there is problem in the ocular surfaces like new malignancies, socket contracture, infections or extrusion of implants. Therefore, the prosthesis should be taken out and scrutinized quite carefully to see any abnormal surface and deposit. If there is any, then it should be buffed out by polishing. If the problem is associated with the ocular surface, it should be treated accordingly which may sometimes even warrant surgeries, for example, in the case of implant exposure, contracted socket syndrome or malignancy.

(c) Dry Eye

Since the ocular surface is highly compromised in anophthalmos and it is even more when there is a prosthetic eye constantly kept in the socket as a foreign body. Hence, the tear volume is less than expected and due to less and compromised goblet cells the quality of tear is also poor. The frictional force against the lid may sometimes give rise to scars and fibrosis along the conjunctival lining. These all result in nothing but a dry eye. The dry eye can be treated by applying lubricating viscous drops like HPMC and CMC. More severe form may mandate 100% medical grade silicone oil which lasts for a relatively long time. Corticosteroid and Cyclosporine A are other options in severe dry eye but these drugs should be used cautiously.

 (d) Lid sequelae

The prolonged uses of prosthetic eye may sometimes result in lid sequelae like lid laxity and ptosis. Ptosis is commonly corrected by adjusting the prosthesis whereby PMMA material is added to lift the superior part of the prosthesis so that it pushes the levator palbepral superioris muscle and abates the degree of visible ptosis. If this type of prosthetic adjustments are done many a time, then consultation with the OPAL surgeon should be made to explore the surgical options for making good ocular spaces. Similarly, contracted socket also requires renovation of the orbital surface to increase the volume for the comfortable prosthetic insertion and acceptable movement.

 (e) Implant related complications

Sometimes the implant might be exposed causing pain. The problems with the implant are magnified if there is a pegged implant. For example, the peg can be broken or its surrounding may harbor bacterial colonies increasing the risk of infections. The patient with these problems should be recommended to visit an OPAL surgeon for a surgical correction.  

1.1.13 Three-D printed Ocular prosthesis

Esthetically appealing and functionally superior ocular prosthesis can be made in modern days by the 3-D printing technology which mainly utilizes Computer Aided Designing (CAD) and Computer Aided Manufacturing (CAM). The process is generally also called as Bio-CAD modeling and is just not used in ophthalmology but also in dentistry and orthopedics (Alam et al., 2017).  The model developed from the medical image processing is adapted to CAD to finally 3D print through rapid manufacturing machine or Polyjet 3D printer. The material used in this process is, as above, medical grade biocompatible Poly Methyl Metha -Acryate (PMMA).

 

References:

Adhikary R, Shrestha K. (2020) ‘Artificial eye: Boon for those with no eyeball’, The Himalayan Times, 5 March. Available at: https://thehimalayantimes.com/opinion/artificial-eye-boon-for-those-with-no-eyeball

Alam, M. S. et al. (2017) ‘An innovative method of ocular prosthesis fabrication by bio-CAD and rapid 3-D printing technology: A pilot study’, Orbit, 36(4), pp. 223–227. doi: 10.1080/01676830.2017.1287741.

Chalian VA, Drane JB, S. S. (1971) Maxillofacial prosthetics: Multidisciplinary practice. Baltimore: The Williams and Wilkins Co.

Chen, W. P. (2001) Oculoplastic Surgery: The Essentials. New York: Stuttgart: Thieme. doi: 10.1055/b-002-41864.

E, W. (1968) Anatomy of the eye and orbit. 6th ed. London: H K Lewis & Co. Ltd.

Goiato, M. C., de Caxias, F. P. and dos Santos, D. M. (2018) ‘Quality of life living with ocular prosthesis’, Expert Review of Ophthalmology, 13(4), pp. 171–173. doi: 10.1080/17469899.2018.1503534.

Kelley, L. (2008) ‘The World Health Organization (WHO)’, The World Health Organization (WHO), (October), pp. 1–157. doi: 10.4324/9780203029732.

Kollewe J, W. G. (no date) ‘ICI: from Perspex to paints’, The Guardian. Available at: www. guardian.co.uk.

Moshfegi, D. M. A. (2000) ‘Enucleation’, Surv Ophthalmol, 44, pp. 270–301.

N., H. (2006) Artificial eyes and the artificialisation of the human face. C Timmerma. Basingstoke: Palgrave.

Le Grand Associates. Available at: http://www.legrandeyes.net. (Accessed: 9 October 2021).

P, Viswanathan; Mandeep S, Sagoo; Jane M, O. (2006) ‘UK national survey of enucleation, evisceration and orbital implant trends’, Br J Ophthalmol., 91(5), pp. 616–619. doi: 10.1136/bjo.2006.103937.

Raizada, K. and Rani, D. (2007) ‘Ocular prosthesis’, Contact Lens and Anterior Eye. doi: 10.1016/j.clae.2007.01.002.

Sajjadi, M. (2007) ‘5,000-year-old artificial eyeball found in Iran’, Times of London, 21 February. Available at: https://historynewsnetwork.org/article/35645.

Smith BC, Della Rocca RC, N. F. (2012) Ophthalmic plastic and reconstructive surgery. Edited by V. III. St. Louis: C.V. Mosby Co.

Verma, A. S. and FitzPatrick, D. R. (2007) ‘Anophthalmia and microphthalmia’, Orphanet Journal of Rare Diseases, 2(1), pp. 1–8. doi: 10.1186/1750-1172-2-47.

Zboralski, K. et al. (2008) ‘Quality of life and emotional functioning in selected psychosomatic diseases’, Postepy Higieny i Medycyny Doswiadczalnej, 62(February), pp. 36–41.