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Corneal tattooing is the practice of tattooing the cornea of the human eye. Reasons for this practice include improvement of cosmetic appearance and the improvement of sight. Many different methods and procedures exist today, and there are varying opinions concerning the safety or success of this practice.
Causes or reasons for corneal tattooing vary from patient to patient, but most patients receive treatment to alter the cosmetic appearance of their eyes due to disease or accident. Some patients also receive treatment for optical purposes, including decreasing a circumstantial glare within the iris. Corneal opacities are the leading cause for cosmetic tattooing.
The leading reason for corneal tattooing is to alter the appearance of the eye cosmetically. Usually, the need for this alteration stems from corneal opacities. Corneal opacities, the scarring of the cornea that creates an opaque or semi-transparent area on the eye, can be caused by leucoma, keratitis, and cataracts. These opacities can be cosmetically disruptive for patients in their everyday lives. Tattooing the cornea can cosmetically alter the discoloration and therefore blend the opacity to a normal eye color. Most physicians agree that the procedure is to be performed on patients that have already lost vision or do not expect visual recovery. Occasionally, corneal tattooing can be performed in cases where it might improve the sight of the eye.
Occasionally, corneal tattooing can be performed in cases where it might improve the sight of the eye. According to Dr. Samuel Lewis Ziegler, indications for this purpose might include albinism, aniridia, coloboma, iridodialysis, keratoconus, or diffused nebulae of the cornea. Corneal tattooing is also occasionally performed on eyes that still have vision in order to reduce the symptomatic glare associated with large iridectomies or traumatic iris loss.
Corneal tattooing has been practiced for almost 2000 years, first mentioned in history by Galen, a 2nd-century physician. Methods of corneal tattooing have at times been practiced often and at other times faded into obscurity, but overall, the methods have evolved throughout history.
Galen of Pergamum, a Roman physician and philosopher, first described corneal tattooing in 150 AD, and the same procedure was later described by Aetius in 450 AD as an attempt to mask the leukomatous opacities of the eye. Both physicians would cauterize the corneal surface with a heated stilet[disambiguation needed]. After the cauterization, they would apply the dye to the eye, using a variety of dyes, such as powdered nutgalls and iron (see iron gall ink) or pulverized pomegranate bark mixed with copper salt. This would then stain the cornea, correcting the cosmetic appearance for the patient. Other sources have mentioned that Galen might have used copper sulphate. This procedure was probably only used on those patients with an unsightly corneal leucoma.
After Galen's reference to corneal tattooing in the 2nd century, the practice is not mentioned until 1869, when oculoplastic surgeon Louis Von Wecker introduced a new method. De Wecker, as he was also known, was the first to use black ink, India ink, or China ink to tattoo a leucoma of the eye. He would first apply cocaine to numb any sensation in the eye and then cover the cornea with a thick solution of ink. He would then insert the pigment into the corneal tissue with a grooved needle obliquely. This method has influenced all subsequent methods since then.
Ziegler writes of several physicians that have contributed to the development of corneal tattooing. Some physicians created new instruments to enhance the tattoo process. Taylor introduced one such new method. He created a bundle of needles to tattoo the eye instead of a single needle, and De Wecker later found this method to be more practical. In 1901, Nieden introduced a method that used a tattooing needle based upon the idea of a fountain pen, or something similar to the Edison electric pen. He found that this electrical needle operated more rapidly and regularly than other traditional methods of tattooing. Another physician, Armaignac, used a small funnel that he fixed to the cornea by three small points. He would then place a portion of China ink into the instrument and proceed to tattoo with a needle. Armaignac claimed that this method produced a perfectly round pupil in one sitting. Other physicians, such as Victor Morax, did not actually tattoo the cornea but still changed the appearance of the cornea. Victor Morax would split the corneal tissue into two vertical layers, introducing the coloring substance under the pedicle flap. He would then apply a compressive dressing over the eye. Various methods have been introduced throughout history, evolving and often improving. They have collectively evolved into several mainstream methods of today that have proved to be the most effective.
Several different methods exist today. Generally in most procedures, the dyeing agent is applied directly to the cornea. The physician then inserts the needle into the eye to inject the dye into the cornea. All physicians agree that the tattoo should be injected intramellarly or laterally, which provides an appearance of a uniform color and minimizes the chance of an irritable eye.
The methods used to apply the ink to the cornea differ. In one such method, the physician applies the ink into the cornea stroma by multiple punctures, covering the needle with ink each time. In another method, the physician would cover a three-edged spatula needle with ink before each puncture. He would then apply the ink into the anterior corneal stroma with each puncture. Samuel Theobald would inject the eye first with a needle and then rub in the ink with a Daviel curet. This would prevent against the often obscure field of operation known to other physicians and also prevent against repetitive irrigation sometimes needed.
Another fairly new method, introduced by Arif O. Khan and David Meyer in an article presented by the American Journal of Ophthalmology, suggests the removal of the corneal epithelium first. The physician would then place a piece of filter paper soaked in platinum chloride 2% onto the area for two minutes, followed by a second piece of filter paper soaked in hydrazine 2% applied for 25 seconds. William Thomson practiced corneal tattooing in a method similar to Nieden. He used a small steel pen manufactured by Joseph Gillott, with the point converted into the cutting surface. The barrel would receive ink for the entire operation, avoiding the need to refill the ink or to recover the needle with ink. This method would avoid the disadvantages of other methods in which the ink impeded the physician's inability to control where the ink spread, which impeded the sight of the cornea to the physician. A plethora of methods exist today with varying techniques and instruments.
Many different types of inks are used throughout history and today for the dyeing of the cornea. Today, India ink is the most commonly used, providing safe and long-lasting effects, but other dyes include metallic colors in powder form, various organic dyes, and uveal pigment from animal eyes. Two different methods exist: chemical dyeing with gold or platinum chloride and carbon impregnation.
Walter Sekundo et al., in the British Journal of Ophthalmology, say that chemical dyeing is easier and quicker than carbon impregnation, but it fades more rapidly than non-metallic tattooing. The West mainly uses chemical dyeing. Some chemical dyes that are commonly used are platinum or gold chloride, which provide a jet black stain.
Carbon impregnation includes the use of India ink, Chinese ink, lamp black ink, and other organic dyes. Snejina Vassileva and Evgeniya Hristakieva, both faculty members at universities in Bulgaria, say that India ink is safe and long lasting when properly diluted and is the most commonly used today.
Some advantages of corneal tattooing include the success and minimum recovery process. Ji-Eun Lee et al., in an article from Acta Ophthalmologica Scandinavica, say, "Corneal tattooing by intrastromal injection of India ink into the amniotic membrane space may be a very useful method of achieving a good cosmetic report." Often, the process is extremely successful and reduces the cosmetic disruption of any corneal opacity. Corneal tattooing may also reduce a glare within the eye due to iris loss and increase visual acuity. J.N. Roy, a professor at the University of Montreal, wrote in the Canadian Medical Association Journal, “Placing a bandage over the tattooed eye is not indicated; ordinary coloured glasses are amply sufficient.” Treatment after the procedure itself is limited, according to Roy, to colored glasses.
Some of the disadvantages of corneal tattooing are the difficulty of performing the procedure and the risk of the procedure. Many people have gone blind from the attempt of the procedure. Corneal tattooing is a procedure that is very difficult to perform precisely. Often, the area tattooed fades after time and rarely remains permanently. The size of the area tattooed also might reduce over time. Sometimes, the results are not what were expected, and the eye might need to be re-tattooed. Also, results may not last very long because of the multiple incisions, and the multiple lacerations might cause recurrent corneal erosions. Finally, not all leucoma respond to the tattooing. J.N. Roy says, "All leucomas do not equally respond to intervention, which must be done only on those which present old, solid and flat corneal cicatrices." Also, there are some considerable dangers linked to corneal tattooing. Some patients complain that it feels like something is in their eye and slight redness. The ink might not remain in the cornea and could possibly cause keratitis. Other complications include "toxic reaction, iridocyclitis, persistent corneal epithelial defects, and corneal ulceration." In summary, the corneal tattooing might not always work successfully, and physicians run into problems such as fading, reduction in size, complications, and short-term results.
New advances in technology have decreased the actual practice of corneal tattooing over the years. Instead, some of the following methods are used to disguise any corneal scarring: corneal grafting, keratoplasty techniques, and tinted contact lenses. Also, advances in technology have decreased the probability of developing a dense corneal leucoma, such as chemotherapy, antibiotics, and the avoidance of "heroic measures of therapy." Although such advances in technology have decreased the popularity of corneal tattooing, some do practice it still. Sekundo et al. even believe that the combination of new technology and old techniques might increase the popularity of tattooing in the future.