Spots on contact lenses .. And how to deal with them accurately
spots on contact lenses And how to deal with them accurately
Deposits are very common in soft contact lenses, but they also occur in gas-permeable lenses.
The deposits diminish the optical quality of the lenses and are the cause of discomfort, being responsible for complications such as giant papillary conjunctivitis and allergic conjunctivitis.
II. DEPOSITS IN SOFT LENSES
The adherence of deposits has a close relationship with the handling of the lenses by the patient, the inadequate solutions and the chemical properties of the tear film. One of the best ways to identify deposits is with the use of the Slit Lamp. The deposits are known for their shape, size, color, texture and can be classified into:
- Protein deposits
- Deposits of lipids
- Inorganic film
- Pigment Deposits
- Mercury deposits
It is important to know the type of deposits to apply the proper handling and know product to remove or prevent the problem, or if the lens can be used on a daily or extended.
In soft lenses it is the most common deposit and one of the biggest causes of allergy. The protein adheres to the surface of the lens and behaves like a foreign body that will irritate the tarsal conjunctiva, being responsible for giant and allergic papillary conjunctivitis.
The causes are: thermal disinfection, a bad blinking, dry eye, chronic allergic conjunctivitis, poor cleaning, use of inadequate solutions and deficiencies in the lens material.
1.1. Appearance to the Slit Lamp.
– The protein deposits, appear as a grayish white semiopaque film, initially in superficial form and then in points that cover a wide area of the lens, hardly penetrate the material.
– The first thing to counteract this problem is the use of a good surfactant and abrasive cleaning liquid, which allows removing the proteins in the initial state of adhesion.
– Also the use of enzymatic cleaners helps us to remove deposits in a deeper way.
The main lipid contaminants give a greasy and oily appearance on the surface of the lens, giving the sensation of poor wetting. This problem can occur due to increased secretion of the Meibomian gland, degeneration of corneal epithelial cells that do not allow good adhesion of the tear film.
Also a bad handling of the solutions by the patient can be a cause of fatness.
Lipids are fats, cholesterol, which in cases of blepharitis or meibomitis increase the problem.
2.1 Appearance of the Slit Lamp
– Upon examination in the slit lamp lipids are observed as patches of fat on the lens; Similar to the fingerprints left on a glass, they give an opaque appearance, losing the material’s wettability.
– Lipid deposits can be eliminated with the use of a cleaning solution, and in difficult cases with deep cleaners for professional use such as “Lipofrin”.
1.3. CALCULATIONS IN THE LENS
The stones are round nodular deposits, located on the anterior surface of the lens, the most frequent is the deposit of calcium, present in the tear film as calcium salts and calcium carbonate salts derivatives.
Normally the calcium salts are dissolved by the aqueous component of the tears, but this mechanism can present alterations and changes like dehydration. The result is that undissolved calcium salts are deposited on the lens being the first step in the formation of the calculus.
3.1 Appearance to the Slit Lamp.
– The calculation is observed as a well-delimited white spot of more or less round shape, varying in its size creates the sensation of a foreign body and penetrates the material.
– The calculations are more frequent in soft lenses for prolonged use, this tells us that it is necessary to change to daily use.
– It is also convenient to keep the lenses the best hydrated, and use deep cleansers when the calculation is not well formed.
1.4. INORGANIC FILM
The inorganic deposits can be confused with proteins of similar color and location, these deposits can not be removed with enzymatic cleaners. The etiology of the inorganic deposit is similar to calcium phosphate and occurs frequently in users with incomplete flicker.
The most frequent deposits are residues of iron, oxide, metals or particles from the polluted environment, pollution, dust, etc.
4.1 Appearance to the Slit Lamp
– These deposits appear as small dots of brown, red or black color that may be embedded in the material and protrude as protuberances.
– Inorganic deposits cause damage to the anterior surface of the lens, they are almost impossible to remove. The indicated thing is the change of lens.
1.5. PIGMENT DEPOSITS
The pigment deposits give the lens a yellow or brownish color on the edge; over time it extends to the entire lens. According to Ruben “the pigment is melanin that is polymerized by oxidation of compounds (aromatic) of tears”
It has also been reported according to Keist “the presence of amino acids or peptides accumulated in the lens matrix, which polymerize just behind the surface of the lens” Oxidative polymerization is favored by heat disinfection.
5.1 Appearance to the Slit Lamp.
Making the diagnosis is quite difficult, the pigmentation is observed in the change of the color of the lens when observing the texture.
These deposits, when they are very deep, can be clarified with the use of hydrogen peroxide repeatedly. Smoking patients should use the peroxide system daily, to prevent the lens from being stained by the presence of aromatic compounds of tobacco.
1.6. MERCURY DEPOSIT
These deposits may appear after the use of solutions preserved with Timerosal in thermal disinfection.The appearance is gray or black.
6.1 Appearance to the Slit Lamp
Early signs of pigmentation will be noted by black discoloration at the edge of the lens.
The lenses must be cleaned with a good surfactant, before being stored for disinfection. Fresh saline should be used each time the lenses are heat sterilized.
The microorganisms are germs, fungi, bacteria, viruses that can penetrate the lens, if the patient has any corneal abrasion, an infection is easily produced that will be favored with the use of unpreserved or sterile solutions, as in the case of saline solutions prepared at home. Additionally, the contamination is due to the lack of good hygiene habits.
7.1 Appearance in the Slit Lamp.
The micro-organisms can appear as gray, brown, pink or white points inside the material. For example fungi tend to form at the edge of the lens.
Mushroom problems can be avoided with a good cleaning and disinfection to avoid contamination.Patients should not use non-sterile solutions for care and preservation. If the lens is diagnosed a micro-organism it must be replaced immediately.
III. DEPOSITS IN LENSES PERMEABLE TO GAS
In the materials of the gas permeable lenses, three basic properties were searched, which are oxygen permeability, wettability and dimensional stability.
These three properties are achieved with the mixture of three monomers:
- Silicone and fluorocarbon for oxygen permeability.
- Methacrylic acid and / or Hema for wettability.
- Methyl-methacrylate for dimensional stability and optical quality.
To the permeable lenses also adhere deposits to him like lipids, fats, proteins that are going to demejorar the humectabilidad.
BAD HUMECTATION IN PERMEABLE LENSES
The bad wetting is the inability of the permeable lens so that its surface is uniform and with liquid adhered.
The non-wetting is manifested by dry spots, gray areas, white, blurred vision and increased lens cleaning.
Objectively we can notice hydrophobic zones, granular surface, adhering residues and grayish coloration.
The poor wetting can be caused by metabolic alterations of the tear film, the use of inadequate solutions and finally problems in the manufacture of the lens.
1.1. Moistening problems in the manufacture of the lens.
In the manufacture of waste such as blocking glue, polishing wax, diamonds to cut material in poor condition, inadequate polishing times, excess heat and solvents can alter the surface of the material.
These causes can create non-wetting areas.
1.2 Organic non-wetting residues.
Organic waste creates thickening and non-wetting surfaces as in the case of cosmetics, there may also be lipids, proteins, mucus, lanolin, etc. in the tear. that alter the good wetting of the material.
For example, lanolin residues present in beauty products such as soaps, skin creams, oils, alter wettability. The remains of cleansing cream, cosmetics produce a hydrophobic surface on the lens.
1.3 Inadequate solutions
The use of cleaning solutions, conditioners or humectants that stimulate the electrostatic reactivity of the lens surfaces such as Benzalkonium Chloride. The biggest problem is that it favors the adherence of deposits of proteins and lipids to the lens.
It is necessary that the solutions are manufactured with products that allow a complete “AFFIXITY WITH THE LAGRIMAL FILM” and there are no problems of wettability.