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Paediatric Contact Lenses

Introduction Fitting contact lenses to children of different ages requires varying skill sets to achieve the best results for the patients. Lenses fall into two main categories: refractive and pathological. Refractive fittings are similar with all ages and, in the main, are fitted by general contact lens practitioners, while significant ophthalmic problems requiring specialist contact lenses are more likely to be fitted in conjunction with an…

Post-refractive Surgery

Introduction For nearly half a century, vision scientists around the world have struggled with the challenge of surgically correcting human refractive error. Typically by employing mechanical manipulation of the corneal tissue, the delicate art of refractive surgery has been greatly refined over the past 40 years, and although great strides have been made in recent years, the nature of ocular surgery and the inherent complications have…

Postkeratoplasty Contact Lens Fitting

Patients who require contact lens fitting following keratoplasty (corneal graft) can be the greatest challenge to a contact lens practitioner. These patients have undergone a major surgical procedure and may be reluctant to revert to or start contact lens wear. The practitioner needs to consider both the practical challenges of fitting the postkeratoplasty cornea and the patient's thoughts and attitude concerning contact lens wear. History of…

High Prescriptions

Introduction Most patients with high prescriptions benefit both optically and cosmetically from contact lenses, more so than patients with low prescriptions. Fitting the lenses is not always straightforward partly due to the different lens thickness but also to the medical aspects of the associated eye condition. Extra vigilance is required at aftercare to ensure that both the health of the eyes and the state of the…

Keratoconus

Introduction Keratoconus (KC) is a term derived from the Greek words keras (cornea) and konos (cone). It was described by Dr Benedict Duddell in 1736 and increasingly described further over the following 100 years with a variety of names including hyperkeratosis, ochlodes, sugar-loaf cornea, cornea conica, staphyloma pellucidum, keratocus, and keratoconus ( ). However in 1854 John Nottingham MD published a treatise where he described in…

Orthokeratology

Introduction In 1996, Dr Tom Reim of Melbourne, Florida, had an idea that changed orthokeratology forever: He designed a lens with a small (0.60 mm) reverse curve (RC) and added a wide alignment curve to overcome the centration problems that were inherent with the then-popular 3-zone lenses. This was the first 4-zone orthokeratology lens, which has gone on to become the most copied design, as virtually all…

Lens Checking: Soft and Rigid

Introduction Successful contact lens fitting requires the manufacture of high-precision contact lenses and the establishment of meaningful tolerances. Such tolerances are established by national and international standards organisations. Poor-quality contact lenses can compromise wearing comfort. Contact lenses therefore have to be verified and/or inspected by the contact lens practitioner during the fitting sessions and follow-ups. Depending on the classification, contact lens type and design, the inspection…

Management of Contact Lens–Induced Pathology

Introduction: Topical Ocular Medications and Contact Lens Wear It is generally agreed that the concurrent use of particularly soft contact lenses and topical pharmaceutical agents in not advisable due to concerns regarding changes to the contact lenses and toxicity to the ocular surface. Components within the eye drop may also absorb into the lens matrix or adsorb onto the lens surface, leading to changes in protein…

Aftercare

Introduction Contact lens aftercare is the key to developing good lens performance and sustaining ocular tissue health; successful contact lens practice depends on this. It provides an opportunity not only to modify lenses and maintenance methods, but also to solve problems of discomfort (the primary reason for discontinuation of contact lens wear; ) so that optimum results are achieved and maintained. Symptoms and signs require differential…

Patient Management

Patient management is the process of careful investigation before a patient is fitted with contact lenses and maintaining successful wear afterwards. It is a means of informing, examining and selecting potential wearers, as well as anticipating or investigating possible causes that may prevent effective contact lens wear. Patient management is also a routine for regular aftercare, dealing with emergencies and treating problems successfully. It is all…

Scleral Lenses

Introduction and History A scleral contact lens rests solely on the sclera. It is intended to vault the cornea in its entirety and to retain a fluid reservoir between the lens and the eye ( Fig. 14.1 ). Scleral lenses were first described in 1888 by . In the early years, glass was the only material available, making lenses difficult to create, wear and reproduce. By…

Bifocal and Multifocal Contact Lenses

Introduction Presbyopia, resulting from a gradual decrement in visual function at near, is one of the most prevalent ocular conditions resulting in patient complaints and dissatisfaction in the 40 and older age group. Nevertheless, it also represents an outstanding opportunity for potential contact lens wearers. Presbyopic patients represent the largest growing segment of the population and the largest untapped section of the contact lens market (…

Extended and Continuous Wear Lenses

Introduction The concept of extended wear (up to 1 week) or continuous wear (up to 1 month) holds considerable appeal for contact lens wearers because it brings them close to the world of the nonwearer. Being able to see clearly, all the time, without glasses and not needing to worry about contact lens cleaning and disinfection is a situation that would be attractive to many of…

Toric Contact Lens Fitting

Fitting Rigid Toric Lenses Indications for the use of rigid toric lenses Rigid toric lenses are indicated in preference to rigid spherical lenses under the following circumstances: ■ to improve vision in cases where a lens employing spherical front and back optic zone radii is unable to provide adequate refractive correction ■ to improve the physical fit where a lens with a spherical back optic zone…

Soft Contact Lens Fitting

Introduction Soft lenses were introduced initially in the early 1970s and now are the most prescribed lens type worldwide, used by 80–90% of contact lens patients ( ). Over the past 45 years there have been numerous improvements in materials and manufacturing techniques. Soft lenses now can be worn successfully on both a daily and overnight basis and are typically replaced on a frequent basis at…

Rigid Gas Permeable Corneal and Corneoscleral Lens Fitting

Introduction With the advent of inexpensive, easy-to-fit hydrophilic lenses, some practitioners have abandoned the art of rigid gas permeable (RGP) lens fitting. However, there are many reasons why practitioners attempting to fit contact lenses with any degree of seriousness should have a detailed knowledge of RGP fitting: ▪ Some patients will get better visual acuity with RGPs. ▪ astigmats ■ irregular astigmats ■ low levels of…

Clinical Instrumentation in Contact Lens Practice

Contact lens practitioners have a range of instrumentation available to them with which they can assess the anterior eye for its suitability to wear or continue to wear lenses, and with which they determine the most appropriate lenses to be fitted. This chapter includes most of the commonly used instruments, although there are others such as the lipid layer interferometer (see Chapter 5 ) which can…

Assessment of Patient Suitability for Contact Lenses

Most contact lenses fitted nowadays are soft as there is such a wide range of parameters available, including toric and multifocal, and made in materials that can be used for all wear modalities. This allows more patients with differing requirements to be fitted with contact lenses. Rigid gas permeable (RGP) materials and scleral lenses are now mainly considered for eyes with pathological or abnormal conditions unsuited…

Tears and Contact Lenses

The quality of the tear film covering the anterior surface of the eye is critically important when considering the challenges of contact lens wear. Contact lens discomfort and dryness are the most common reasons for reduced lens wearing times and lens discontinuation ( * * The Tear Film and Ocular Surface Society (TFOS) organised an International Workshop on Contact Lens Discomfort (CLD) involving 79 experts and…