Archives: Lessons

Onboarding: Training for Eye Care Professionals Glossary   ABBE Value: Measures the dispersion of light through a lens material, indicating how well it reduces chromatic aberration. A higher Abbe value means less color distortion and clearer vision Abduction: The movement of the eye outward, away from the nose ABO exam: Certification exam administered by the … Continued

Contact Lens Complications and Resolutions Introduction  Contact lens related complications can range from mild and self‐limiting to severe and sight threatening, which require rapid diagnosis and treatment to prevent vision loss. Millions of individuals wear contact lenses, so even a small percentage of patients experiencing complications can constitute a significant public health problem. Serious eye … Continued

Tear Film The tear film provides a smooth and transparent refractive surface, essential moisture, and oxygen to the epithelial cells. The tear layer also contains proteins which help protect against infection. The health of the ocular surface is entirely dependent upon an adequate quantity and quality of tear film, both of which can be altered … Continued

Cornea Mechanical Epithelial Defects Technically, the contact lens is a foreign body that rubs across and is pressed against the corneal epithelium with each blink, thousands of timeseach day. Surprisingly, this only occasionally results in an abrasion. Corneal abrasions from contact lens wear need to be recognized and treated because they indicate chronic epithelial stress … Continued

Pre-Existing Factors and Post-Wear Complications Many tests conducted during the evaluation and initial fitting of a contact lens patient might point to pre‐existing conditions that can be exacerbated by contact lens wear. Sometimes conditions or complications are only revealed after contact lenses have been worn for some period of time. Many clinicians will simply refuse … Continued

Epithelial Defects Staining Patterns Using the Biomicroscope and Fluorescein Chemical Epithelial Defects Various contact lens chemical solutions can produce a range of epithelial defects from marked erosions to less extensive punctate defects. Surfactant cleaning solutions that are left on the lens after cleaning can cause: immediate pain, redness, photophobia, and tearing upon lens insertion. These … Continued

Complications Symptoms and Signs Table

Lids Giant Papillary Conjunctivitis (GPC)  Giant papillary conjunctivitis is a common complication among contact lens wearers. It is an inflammation of the tissue called the tarsal conjunctiva, which is located underneath the upper lid. The inflammation is diagnosed by the appearance of large swollen processes which make the tarsal conjunctiva appear to be covered with … Continued

Stroma  The corneal stroma can show signs of hypoxia and damage. Striae (folds) are revealed with the use of the slit lamp employing the optical cross‐section view. Corneal thickening can be tested with pachymetry and is likely due to hypoxia and resulting edema. Neovascular changes can appear in the stroma when a patient experiences chronic … Continued

Corneal Hypoxia Corneal hypoxia can be acute or chronic. It is one of the most common complications of contact lens wear, and if not treated rapidly and effectively,it can lead to edema, corneal damage and possible vision loss. When the eye is open, the cornea receives 21% oxygen from the atmosphere, diffused through the tears. … Continued

Pseudomonas Aeruginosa Pseudomonas Aeruginosa is a water borne pathogen that can be found in bottles of eye drops and other solutions after they are opened and the sterile seal is broken. This organism can potentially destroy an eye in as little as 48 hours. This gram negative bacillus thrives well in pre-bottled solutions of fluorescein, … Continued

Tonicity Tonicity is extremely important to the ocular surface and the tears. The natural tear has a tonicity of approximately 0.9% sodium chloride. Sterile saline has a tonicity that is approximately that of natural tears and is well tolerated by the eye. Most of the all‐in‐one solutions, as well as the soaking solutions that are … Continued

Summary All eyes are altered to some extent by contact lens wear. Abnormalities of the lids, conjunctiva, epithelium, stroma, and endothelium might be produced. The changes run the gamut from incidental findings without any apparent functional significance to potential painful and sight‐threatening pathology. Fortunately, the contact lens fitter can help to assure that contact lens … Continued