Dedication
This book is dedicated to my son John Leslie.
Preface
This book represents some of the knowledge I have managed to gain through many years of clinical contact lens practice. Since my pre-graduate training in the early 1980s the field of contact lens practice has shown tremendous and exciting growth, making it impossible to include all that has been learnt in a text book such as this. In writing this book I have leant heavily on the shoulders of giants who are responsible for the clinical research which this book is based on. Although this book has been written with my pre-graduate students in mind, even the expert contact lens practitioner will find something of interest or at the very least refresh their knowledge of current contact lens practice.
Dr. Dirk J. Booysen
December 2017
Acknowledgements
This book would not be possible without the support of my wife Sarah Leigh who kindly did some of the illustrations as well as my colleagues Gerrie Kruger who helped with some of the editing and Marolize Botha who wrote the chapter on optics and helped with the digital illustrations and diagrams. Finally I would like to thank my colleagues Alan Saks and Pat van Poser for taking the time to write the foreword.
Foreword
I first met Dirk Booysen at orientation in his first year at Optometry School in Johannesburg when I was in final year. I have since followed his sterling career with interest. Even though I left South Africa in 1993, my Dad, Sid Saks –one of the few surviving contact lens pioneers – has kept me up to date. Dad was always impressed with Dirk’s professionalism, knowledge, ethics and standards of practice, as are many others in the optometric and contact lens field, me included. Dirk never seems to sit still. I’ve had various interactions with him, at international meetings like the BCLA in the UK, where he’s a regular attendee, striving to always stay ahead of the game. It’s always good to catch up and chew the fat with Dirk, as we recently did, when we presented at the Contact Lens Society meeting in Johannesburg, in late 2017.
Dirk has always managed to blend the academic and clinical side of optometry rather well and has been active in Optometric and Contact Lens Education in South Africa, over many years. His passion and skills have gained him many fans among his patients and through his contact with optometry students. He mentors a number of up and coming stars.
It was in part his desire to educate at the highest level that set him on course to create this outstanding tome, ‘In Contact: Clinical Contact Lens Practice’. Let me say unequivocally that this textbook is more than a simple collection of lecturers’ notes. It is a book worthy of its place as a go-to contact lens reference, not just for South African optometry students but also internationally and is certainly worth a read by practitioners too. I found it an excellent refresher and learnt quite a few things on the way. Dirk and I discussed a few of the finer points and debated some of the statements made.
The book is beautifully laid out with superb clinical images, tables, diagrams, and graphs, which support the text and follow a logical path.
The various chapters cover most aspects of clinical practice and support this with over five hundred clear references. Dirk has managed to blend the importance of the evidence base with the reality of clinical practice – along the lines of some of the leading texts in the field; from an academic like Nathan Efron, who is also very clinical and Tony Phillips, a clinician, who also manages the academic side very well. This puts Dirk’s first attempt at a textbook right up there with experienced writers with many publications under their belt.
‘In Contact: Clinical Contact Lens Practice’ is right up to date on many aspects of research, clinical practice and philosophies, as well as materials, solutions, designs and leading edge technologies such as topography, OCT, eye surface profilers and the like. The latest evolutionary developments, like scleral lenses and myopia control, are also well detailed.
Before most South African practitioners were even using diagnostic drugs, Dirk was already studying therapeutics overseas. His excellent knowledge in this field, as well as pharmaceuticals, has also meant that in each section, where relevant, he mentions therapeutic management and has also dedicated an entire chapter to this evolving field in optometry.
Somehow Dirk not only manages to run a high-end sophisticated practice, as well as lecture at optometry school and conferences, but also manages to spend time with his family while enjoying the bush, beaches and all that beautiful South Africa has to offer. He even finds time to manage an impressive collection of aircraft and fly his beloved, vintage Tiger Moth bi-plane.
An impressive effort or as we colloquially say “Mooi so, Boet”.
Alan Saks
February 2018
Contents
- Dedication 2
- Preface 2
- Acknowledgements 2
- Foreword 2
- The History of Contact lenses [1-3] 11
- Anatomy and physiology of the eyelid, conjunctiva, limbus, cornea, and tear film. 16
- Collagen 16
- Eyelids 16
- Skin 17
- Muscles 17
- Sub-muscular areolar tissue 18
- Orbital septum and tarsal plates 18
- Palpebral conjunctiva 18
- Glands of the eyelids and conjunctiva 18
- Blood supply and lymphatics 20
- The conjunctiva 20
- Epithelium 20
- Stroma 21
- Mast cells 23
- Nerve supply 23
- Blood supply and lymphatics 23
- The Limbus 23
- Epithelium 24
- Bowman’s membrane 24
- Stroma 24
- Descemet’s membrane 24
- Endothelium 24
- The Sclera 25
- Episclera 25
- Scleral Stroma 26
- Lamina Fusca 26
- Penetrations of the sclera 26
- Anatomy of the cornea 26
- Epithelium 27
- Bowman’s membrane 28
- Stroma 29
- Dua’s layer 29
- Descemet’s membrane 29
- Endothelium 30
- Corneal sensory innervation 31
- Physiology of corneal hydration 32
- Corneal transparency 32
- Oxygen, glucose and the biochemistry of the corneal and pre-corneal fluids 32
- Oxygen availability and solubility 32
- Glucose supply and utilization 32
- Buffering and osmolarity 33
- Hydration of the corneal stroma 34
- The role of the corneal epithelium in maintaining corneal hydration 34
- The role of the corneal endothelium in maintaining corneal hydration 35
- How much oxygen does the cornea require to maintain normal physiology? 36
- Permeability (Dk), transmissibility (Dk/t or Dk/L), EOP, oxygen flux, and consumption [32] 36
- Physiology of corneal defence mechanisms [40, 41] 39
- Ocular defence mechanisms [11, 43] 39
- Corneal specific defense mechanisms [11, 21, 43-46] 39
- Why does contact lens wear predispose the cornea to infection?[21, 45, 46] 40
- What are the effects of severe hypoxia on corneal cell function [11, 20] 41
- The tear film 41
- Functions of the tear film [5, 20] 43
- Effect of a Contact Lens on the Tear Film [47, 51-55] 43
- Biophysical changes 44
- Blink impact on pre-corneal and pre-lens tear film spread and volume 44
- Lipid layer 45
- Tear film stability 45
- Tear film evaporation 45
- Tear film temperature 45
- Tear film thickness 45
- Tear production/turnover 45
- Tear volume 46
- Tear exchange 46
- Osmolarity 46
- Tear pH 46
- Viscocity 46
- Surface tension 46
- Biochemical changes 46
- Lipodome 47
- Proteome 47
- Mucin 47
- Examining the contact lens patient [86-89]. 48
- The Slit Lamp Bio-microscope. 48
- Conjunctiva, cornea, sclera and lids. 48
- Measuring the cornea and sclera [86-89] . 52
- Keratometry. 52
- The Placido disc, photokeratoscope and corneal topographer [90-92]. 53
- Scheimpflug or Pentacam corneal tomography [91]. 56
- Anterior segment optical coherence tomography (AS-OCT) [96]. 57
- Measuring the sclera [97-99]. 58
- The Burton lamp [88]. 59
- Vital dyes – Fluorescein (NAFL), Fluorexon, Rose Bengal, and Lissamine Green [100]. 59
- Examining the tear layer [48, 49, 88, 101, 102] 60
- Quantity of Tears (lacrimal and accessory glands) 61
- Quality of tear film and the mucus layer (conjunctival goblet cells, corneal epithelium glycocalyx, lacrimal gland) 61
- Ocular surface assessment 61
- Contact lens Care Products on the South African Market 63
- Buffers and salts 63
- Preservatives 63
- Cleaning agents or surfactants (Surface acting agents) 64
- Chelating agents 64
- Demulcents 65
- Wetting agents/Lubricants 65
- Hydrogen Peroxide 65
- Enzyme cleaners 65
- “To rub and rinse or not to rub and rinse” 65
- Solution and lens material compatibility (www.staininggrid.com) 66
- Contact lens solutions available on the South African market 68
- Contact Lens Materials Available in South Africa 70
- Soft Lens Materials and their properties 70
- Water content 71
- Silicone Hydrogels 71
- Wettability and Wetting Angle 72
- Coefficient of friction 73
- Dehydration 73
- Deposits [103, 112, 116, 117] 73
- Modulus of Elasticity [113-115] 74
- RGP Materials 75
- RGP Material Properties 75
- Soft Lens Materials and their properties 70
- Commonly used Rigid Gas Permeable Lens Designs in South Africa courtesy of The Contact Lens Laboratory of SA 80
- Gas Permeable Lens Modification courtesy of The Contact lens Laboratory of SA. [87] 82
- Lens Parameters That Can Be Modified 82
- Lens Parameters That Cannot Be Modified And Therefore Require Ordering A New Lens 82
- Lens Polishing or Surface Finishing 82
- Lens Power 83
- Increasing Minus 83
- Increasing Plus Power 84
- Peripheral Curve Modifications 84
- Blending Curves 85
- Edge Modifications 85
- Soft Contact Lens Designs 86
- Fitting Soft Contact Lenses 95
- Lens Parameters Affecting the Fit of Soft Lenses 95
- Ocular Parameters Affecting the Fit of Soft Lenses 95
- Determining Lens Power and Thickness 98
- Fitting the Lens [1, 88, 89]. 98
- The Effect of the Tear Film on Soft Contact Lens Fit 99
- Evaluating Lens Comfort [1, 88, 89, 131] 99
- Eye Shape and Soft Lenses 100
- Ideal Fitting Characteristics of a Soft Contact Lens 100
- Objective and Subjective findings with Good, Steep and a Loose Fitting Soft Contact lenses 101
- Rules of Thumb with regard to Soft Lens Fitting [88] 101
- Rigid Gas Permeable Corneal Lens Fitting 102
- Patient examination and initial measurements 102
- Horizontal visible iris diameter (HVID 102
- Visible palpebral aperture (VPA) 102
- Pupil diameter/size 102
- Corneal curvature 102
- Corneal astigmatism 102
- Principles of RGP lens fitting 103
- Assessing the lens fit 103
- Aligned fitting characteristics 103
- Flat fitting characteristics 104
- Steep fitting characteristics 105
- Decentration 105
- Increased movement 105
- Decreased movement 105
- Basic rules of thumb for alterations to maintain fitting relationship OZD and BC: 106
- Toric Base Curve Lens Formula 106
- Vertex and Residual Astigmatism Formula 106
- BC and BVP: 106
- Tables of Subjective and Objective Findings with RGP Corneal Lenses, their Probable Causes and Correction 106
- Patient examination and initial measurements 102
- Astigmatism 110
- Residual Astigmatism (RA) 111
- Incidence of RA. 111
- Correction of RA . 111
- Toric RGP lenses [1, 88, 89, 128] 112
- Front surface toric lenses with spherical back surfaces [1, 88] [146, 147] 112
- Toric peripheral curve lenses with spherical base curves– Asticon or toric second curve lenses [1, 88, 146, 147] 112
- Back surface toric with spherical front surface [1, 88, 146, 147] 112
- Bitoric lenses [1, 88, 146, 147] 112
- Toric soft contact lenses [1, 88, 89, 128, 148] 112
- Methods of stabilization [1, 88, 89, 128, 148] 113
- Lens markings 114
- Residual Astigmatism (RA) 111
- Presbyopia 116
- Important factors for presbyopic patient selection [152] 116
- High probability for success 116
- Moderate probability for success 116
- Low probability for success 117
- Single-vision contact lens wear and reading glasses 117
- Monovision 117
- Disadvantages/problems 118
- Patient selection 118
- Lens selection and fitting considerations 118
- Bifocal and multifocal contact lenses 119
- Terminology 119
- Important factors for presbyopic patient selection [152] 116
- Keratoconus 122
- Definition 122
- What is the role of inflammation in the pathogenesis of keratoconus? 122
- Epidemiology 123
- Aetiology 123
- Heredity 123
- Associated systemic disorders 124
- Eye rubbing 125
- Hormonal changes 126
- Sun exposure 126
- Geographic location 126
- Rigid contact lenses 126
- Aetiology summary 127
- Risk factors for keratoconus 127
- Histopathology 128
- Diagnosis 128
- Diagnosis: Index-based systems 132
- Diagnosis summary [163, 172] 133
- Classification 134
- Corneal biomechanics 136
- Differential diagnosis 136
- Pellucid Marginal Degeneration [219] 136
- Keratoglobus [220] 136
- Posterior keratoconus [221] 137
- Management of keratoconus [163, 165, 172, 222] 138
- Spectacles [163, 172] 138
- Contact lenses [88, 163, 172] 138
- The use of soft contact lenses in keratoconus [223] 141
- Piggy Back and Hybrid lenses 145
- Surgery [239] 147
- Complications of keratoconus 147
- Progression 148
- “Forme fruste” keratoconus 148
- Corneal Scarring 148
- Acute hydrops [197] 148
- Conclusion 149
- Orthokeratology or corneal reshaping technology (CRT) 151
- Indications for orthokeratology [88] 152
- Contraindications for orthokeratology [88] 152
- The anatomy of a reverse geometry lens 152
- Base Curve (BC) 153
- Reverse Zone 153
- Relief Zone 154
- Alignment Zone 154
- Secondary/Peripheral Zone(s) 155
- Overall Lens Diameter 155
- Lens Material 155
- Clinical information required for lens design 155
- When is a toric lens required? 155
- Designs for children versus adults 156
- Complications and side effects of orthokeratology 156
- Microbial keratitis (MK) in orthokeratology 156
- Corneal Staining/Lens Binding 156
- Epithelial Iron Deposit/White Lesion/ Fibrillary Lines 157
- Endothelium in orthokeratology 157
- Corneal Biomechanics 157
- Fitting problems 157
- Conclusion 158
- Case 158
- Scleral lenses 161
- Terminology 161
- Anatomy of a scleral contact lens 162
- Indications for scleral lenses 162
- Fitting Process 162
- 5 step fitting system [15] 163
- Step 1: Choosing the overall lens and optic zone diameter 163
- Step 2: Corneal and Limbal Clearance 163
- Complications 173
- What is the effect of scleral lenses on IOP? 176
- Fitting pearls [15] 176
- Ideal mini-scleral lens: 177
- Rose K2 XL semi-scleral lens 177
- What adjustments can be made to South African manufactured mini-scleral lenses? 177
- Power changes 177
- Edge Lifts 178
- Adding a toric periphery. 178
- Diameters 178
- Fenestrations 178
- Limbal blending 178
- Pterygium Notch 178
- Chip removal 178
- Engraving 178
- Hollow-out 178
- Complications of contact lens wear 179
- Innate or natural, non-adaptive immune system[341, 342]. 179
- Adaptive, acquired or specific immune system[341, 342] 180
- B cells 180
- T cells 181
- Humoral vs. Cell Mediated Immunity [341, 342] 181
- Immunological memory [341, 342] 182
- Innate Immunity vs. Adaptive Immunity: A summary[341, 342] 182
- Cytokines and their role in mediation and regulation of the innate and adaptive immune system[341, 342] 182
- Hypersensitivity reactions[341, 342] 184
- Type 1 hypersensitivity reaction 184
- Type 2 hypersensitivity reaction 185
- Type 3 hypersensitivity reactions 185
- Type 4 hypersensitivity reactions 185
- Type 5 hypersensitivity reactions 186
- Inflammation [343] 186
- When dealing with C/L complications the following mnemonic is handy to remember: 187
- When dispensing lenses invite your patients to: 187
- Hypoxia 188
- Mechanical/lid complications 189
- Blinking 189
- Effect of contact lenses on blinking 190
- Contact Lens Induced Lid Ptosis (CLIP) 191
- Management of CLIP [21] 191
- Mucin Balls 192
- Conjunctival complications 193
- Conjunctival redness 193
- Contact Lens Induced Papillary Conjunctivitis (CLPC) or Giant Papillary Conjunctivitis (GPC) 194
- Limbal complications 195
- Limbal redness 196
- Vascularized Limbal Keratitis (VLK) 197
- Aetiology 198
- Management [21] 198
- Prognosis and differential diagnosis 198
- Contact Lens Induced Superior Limbic Keratoconjunctivitis (CLSLK)[21] 198
- Corneal complications 200
- Corneal oedema 200
- Corneal abrasions 207
- Stromal thinning 209
- Deep stromal opacities or contact lens associated deep stromal opacities (CLADSO) 209
- Corneal neovascularisation(CNV) 210
- Infiltrative and Microbial Keratitis 216
- Definitions [120] 216
- Sterile Infiltrative Keratitis 217
- Microbial Keratitis (MK) 220
- Why is contact lens wear associated with an increased risk of MK? 221
- More about these disease causing microorganisms[442] 223
- Protozoa 226
- Medical Treatment Strategy for Infiltrative and Microbial Keratitis [372] 227
- Small non-staining peripheral infiltrates with minimal anterior chamber involvement and discharge, and low risk of vision loss 228
- Medium size (1 -1.5mm), peripheral infiltrate with overlying epithelial defect, anterior chamber reaction and discharge, and borderline risk of vision loss 228
- Vision threatening – any ulcer larger than 1 -2mm in the visual axis which is unresponsive to treatment 228
- Antibiotics 229
- Corneal endothelial complications 231
- Endothelial bedewing 231
- Endothelial blebs 232
- Endothelial polymegethism 234
- Mechanical/lid complications 189
- Contact Lens Deposits 237
- Proteins 237
- Lysozyme 237
- Lipocalin 237
- Lactoferrin 238
- Albumin 238
- Secretory IgA (sIgA) 238
- Lipids 238
- Mucins 239
- Material properties and contact lens deposits 239
- Protein denaturation 241
- Deposits on RGP lenses 241
- Conclusion 241
- Proteins 237
- Basic Principles of Contact Lens Optics by Marolize Botha 243
- Power of a contact lens and tear film 243
- Compensation for vertex distance 246
- Residual Astigmatism 247
- Myopia control 250
- Introduction 250
- Classification and aetiology 250
- Prevalence 251
- Should we be concerned? 251
- The nature of eye growth and what drives excessive eye growth in myopia? 252
- Predicting myopia onset and progression 252
- Myopia control strategies 253
- Suggested myopia protocol 255
- Conclusion 256
- Therapeutic use of contact lenses 257
- Indications for bandage lenses 257
- Unusual or distorted corneal shape 257
- Pain relief 257
- Recurrent corneal erosions (RCE) 257
- Corneal ulcers 258
- Dry eye and keratitis sicca 258
- Postoperative complications 258
- Contraindications for therapeutic lens wear 259
- Which lens should be used? 259
- Therapeutic lenses as drug delivery systems 261
- Vertex charts, cheat sheets, grading scales, and other useful stuff 263
- Vertex Conversion Chart 263
- Cheat sheet 264
- RGP Base Curve Selection 264
- Toric Base Curve Lens Formula 264
- Soft lens Bas Curve Selection 265
- Tear Lens Changes with Base Curve Changes 265
- Diopter Conversion Formulas 265
- Vertex Formula 265
- Residual Astigmatism 265
- Can IOP be measured with a soft contact lens in situ? 265
- Index 266
- Glossary 268
- About the Author 270
Chapter 1
The History of Contact lenses [1-3]
In his 1508 “Codex of the Eye”, Italian inventor Leonardo da Vinci speculated that submerging the head in a bowl of water could alter vision. He even created a glass lens with a funnel on one side so that water could be poured into it, but the device was impractical. His ideas far exceeded the technology of his times to actually implement them. However, he had correctly identified several key principals of contact lenses; neutralizing the refraction of the cornea by means of an artificial surface; substituting the refractive powers of a curved clear lens in its place; and positioning that lens directly on the eye. In 1632, after reviewing Leonardo’s work, French scientist René Descartes proposed another idea: placing a glass tube filled with liquid in direct contact with the cornea. Descartes’ invention worked somewhat to enhance vision; however, using it made blinking impossible. Although his idea was not practical, placing the lens only over the cornea instead of including the sclera was most perceptive. Improvements in the design of contact lenses would not be seen again for nearly two centuries.
In 1801, English scientist Thomas Young made a basic pair of contact lenses based on Descartes’ idea. He changed Descartes’ contact lens design by reducing the size of the glass tube to ¼ inch and then using wax to stick the water-filled lenses to his eyeballs. He was also the first to accurately describe astigmatism, greatly advancing the field of eye care. However, Young’s device was not practical, nor was it able to correct vision problems. In fact, the idea of using contact lenses to correct the refraction errors that cause nearsightedness, farsightedness, and astigmatism wasn’t suggested until 1845. English physicist Sir John Herschel was the first to hypothesize that taking a mold of the cornea might produce lenses that could correct vision. However, without the necessary technology, Herschel was unable to test his hypothesis, and his theory remained mere speculation until nearly 100 years later.
The early 1880s were a revolutionary period for contact lenses. The development of anesthesia in 1884 allowed for making a mold of the anterior shape of the eye as proposed by Herschel, and new glass production, cutting, and shaping technologies made thin lenses possible for the first time. Designs for glass contact lenses that fit in the eye, allowing the wearer to blink, were independently invented by three men: Adolf Fick, Edouard Kalt, and Louis J. Girard. Credit for the discovery usually goes to Dr. Fick, a Swiss physician who wrote a treatise entitled “A Contact Spectacle,” in which he described the first contact lens with refractive power for visual improvement. The first physical example of the lens was made by artificial eye-maker F. A. Mueller in 1887. These types of contact lenses were called scleral lenses, and they covered the entire eye, not just the cornea. They were slightly convex, allowing room for tears or a dextrose solution—the liquid that creates the refractive power to correct vision—to fill the eye much like Da Vinci’s bowl of water. In 1888, Fick constructed and fitted the first successful contact lens (both corneal and scleral). However, there were two major issues with Fick’s contacts: the lenses were made from heavy blown glass and were 18–21mm in diameter. The weight alone made them uncomfortable to wear, but worse, the glass lenses covered the entire exposed eye. Unlike other bodily organs, which are oxygenated by the blood, the eyes get their oxygen directly from the air. So covering your eyeballs with glass shields is, essentially, suffocating them. Scleral lens wearers experienced excruciating eye pain after a few hours of use. Nonetheless, glass scleral lenses were the main form of contact lenses used for pathological conditions such as keratoconus and other severe distortions of the cornea where correction with spectacles was not possible for the next 60 years.
By the late 1920s, technological advances in both anesthesiology and materials finally allowed Sir John Herschel’s ideas about creating molds of the cornea to be tested. In 1929, Dr. Dallos and Istvan Komàromy of Hungary perfected a method of making molds from living eyes, proving Herschel’s theories. For the first time, it was possible to create contact lenses that conformed to the actual shape of the eye. In 1936 Feinbloom in the USA was the first to use plastic in contact lenses; he produced a scleral lens by bonding the glass corneal potion to an opaque molded resin scleral band. Orbig and Mullen also in the USA followed Feinbloom and in 1938, using an new material, polymethyl methacrylate (PMMA), which is easy to shape to ultrathin dimensions and greatly superior to glass in safety, lightness and workability, made the first all-plastic scleral lens. This “unbreakable”, “scratch-resistant”, malleable, and easy to manufacture plastic revolutionized the contact lens industry, making glass lenses quickly become obsolete. But even though the new lenses were plastic, they were still scleral lenses, covering the entire eye and only wearable for a few hours at a time.
In 1948, an English optical technician named Kevin Touhy was sanding down a plastic lens when the part that covered the white of the eye fell off. Rather than start over, he decided to try the smaller lens. He smoothed the edges and popped it in his eye, delighted to discover that the lens still worked and stayed in place, even when blinking. This happy accident was the birth of the corneal lens, the type most commonly used today. The discovery allowed wearers to leave their contacts in longer, as the eyes could breathe somewhat better and the corneal lenses were more comfortable than scleral lenses. After Touhy’s invention became public, a number of other changes were rapidly introduced to these types of lenses. In 1950, George Butterfield came up with the idea of a curved, rather than flat, corneal lens design. Later in the 1950s, Frank Dickenson, Wilhelm Sohnjes, and John Neil created thinner lenses, of about 0.20 millimeters center thickness. Even thinner lenses, of about 0.10 millimeters, were introduced in the early ‘60s. However, even with all these improvements, corneal lenses still hindered oxygen flow to the eyes and couldn’t be worn for long periods or overnight.
That was soon to change, beginning in 1958. At that time, Czechoslovakian chemists Otto Wichterle and Drahoslav Lim was developing a new type of plastic, called hydrogel, that was soft and pliable when wet, yet could be shaped and molded. Together with Dr. Dreifus, an ophthalmologist they began to research and formulate hydrogel contact lenses. The basic hydrogel plastic is hydroxyethyl methacrylate (HEMA) and absorbs water (as much as 85 to 90%) and becomes flexible in proportion to their water absorbency. An optometrist named Dr. Robert Morrison, of Pennsylvania, became aware of Wichterle’s work and recognized its potential for contact lenses. Wichterle released his patents for worldwide use, and a manufacturing facility for hydrogel soft lenses was set up in Dr. Morrison’s lab. In 1960, Bausch and Lomb was granted access to the hydrogel and took the material to new levels, including creating a refined casting technique that produced consistent lens surfaces, as well as a process for mass production. Ciba Vision’s introduction of silicone hydrogels in 1998 offered extremely high oxygen permeability. Both hard and soft contact lenses continued to improve over the next 25 years, especially in terms of oxygen permeability, to allow the eyes to breathe.
The history of the development of contact lenses is considerably more detailed and complex than is suggested by this discussion of its significant developments or a chronological listing of its highlights presented in table 1. Today’s wide range of precision made, carefully fitted, and extensively used contact lenses represents the contributions of a large number of scientific areas such as biology, physics, chemistry, precision glass making, plastics and polymers, precision tool making, ophthalmic science and their continually expanding theoretical and empirical foundations. Finally many individual eye-care practitioners, technicians and scientists contributed to the development of the contact lens and its use in eye-care.
| 1508 | Codex of the eye, Manual D. Leonardo da Vinci | Italian inventor Leonardo da Vinci speculated that submerging the head in a bowl of water could alter vision. He even created a glass lens with a funnel on one side so that water could be poured into it, but the device was impractical |
| 1632 -1636 | René Descartes | Furthered the evolution of contact lenses with a suggestion of corneal lenses |
| 1801 | Thomas Young | On the basis of Descartes idea, used a ¼ inch long glass tube with a microscopic lens at the outer end and the open end on his eye, filled with water to correct his own vision |
| 1827 | Sir John Herschel | Suggests grinding a glass contact lens to conform exactly to the eyes surface. He also suggested taking a mould of the eye to ensure accurate fitting. This became possible in 1884 with the development of anaesthesia. Sir Herschel was also the first person to describe the concept of cosmetic lenses. |
| 1887 | F E Mueller | Prosthetic eye manufacturer becomes the first to produce a glass eye covering that can be seen through and tolerated. The “glass lenses” were designed for protection and could be only worn for very short periods. |
| 1888 | A. Eugen Fick a Swiss Physician, Edouard Kalt a Paris Optician, and Louis J. Girard | Simultaneously reported the use of glass contact lenses to correct optical defects |
| 1929 | Joseph Dallos a Hungarian Physician | Developed methods of taking moulds from living eyes so that lenses could be made to conform to individual eyes. This enabled mass production of glass contact lenses which conformed to the actual shape of the eye. |
| 1936 | William Feinbloom a New York Optometrist | Manufactures the first American made contact lenses and introduces the use of plastic hard lenses. |
| 1945 | American Optometric Association (AOA) | Formally recognises the growing contact lens field by specifying contact lens fitting as an integral part of the practice of Optometry |
| 1948 | Kevin Tuohy a California Optician | Filed a patent for the first corneal contact lens made entirely of PMMA – polymethyl methacrylate |
| 1950 | George Butterfield a Oregon Optometrist | Designs a corneal lens that follows the corneal curvature instead of fitting flat increasing comfort and tolerability. The shape was paraboloid and used peripheral curves – precursor of all modern rigid lenses |
| 1957 | John DeCarle | Developed simultaneous-vision bifocal contact lenses |
| 1960’s | George Jessen | Created the first Orthokeratology design under the term “autofocus” |
| 1960 | Otto Wichterle and Drahoslav Lim from the Institute of Macromolecular Chemistry – Czechoslovak Academy of Sciences Prague | Introduced water-swollen, hydrophilic, cross-linked polymers (PHEMA or Poly hydroxyethyl methacrylate) and “soft lenses” are born. PHEMA are available on the market in Western Europe from 1962. |
| 1965 | National Patent Development Corporation (NPDC) | Bought the licence covering soft contact lenses from the Czechoslovak Academy of Sciences |
| 1965 | Bausch & Lomb | NPDC sub-licensed the patent for soft lenses to Bausch & Lomb. This initiated the soft lens industry in the USA. |
| 1968 | US FDA – Federal drug administration | FDA regulation of contact lenses is introduced |
| 1971 | Bausch & Lomb | B&L received approval from the FDA for their spin cast PHEMA lenses |
| 1970’s | John DeCarle | Demonstrated that if the water content of soft contact lenses could be sufficiently increased, extended wear was possible |
| 1975 | John DeCarle | First extended wear lens distributed in the UK – 71% water content “Permalens”. |
| 1974 | Norman Gaylord – Polycon laboratories | First siloxane-based rigid lens material – merging the properties of methyl methacrylate with the increased oxygen performance of silicone rubber. |
| 1978 | First toric contact lenses with both spherical and cylindrical power correction introduced in the USA | |
| 1979 | First rigid gas permeable (RGP) lenses appear | |
| 1981 | John DeCarle | “Permalens” received FDA approval for 30 day extended wear. |
| 1982 | Synoptic Group – Denmark | In 1982 the world’s first disposable contact lens was introduced, the MIA lens – marketed as the ‘Danalens’ by the Synoptic group. As the name implies, this came from Denmark. MIA stands for Michael, Inga and Annette (the inventor, his wife and daughter). The technology for the MIA/Danalens lens was subsequently bought by Johnson & Johnson who changed lots of it and renamed it. |
| 1982 | First commercially available bifocal lenses were introduced for daily wear | |
| 1983 | First tinted RGP lenses introduced | |
| Later part of 1980’s and early 1990’s | Hydron | Non spherical and diffraction progressive multifocal lenses were developed by Hydron (Echelon lens) and others |
| 1987 | Johnson & Johnson | Johnson & Johnson launched their own disposable contact lenses in the USA in 1987, ‘ACUVUE’ . |
| 1987 | First tinted cosmetic soft contact lenses were introduced | |
| 1987 | First multipurpose lens care products introduced | |
| 1987 | Fluorosilicone acrylate material introduced for RGP lenses | |
| 1988 | Johnson & Johnson | In 1988 Johnson & Johnson launched two products in the UK designed to suit different lifestyles. The daily wear Acuvue was taken out each night and required replacing every fortnight. The extended wear Acuvue could be worn for longer but required replacing every week. |
| 1989 | Johnson & Johnson Bausch & Lomb Pilkington Barnes-Hind | The two big rivals to Johnson & Johnson were Bausch & Lomb and Pilkington Barnes-Hind. Both first issued a competing lens in 1989: Bausch & Lomb produced a polymacon lens called the ‘Seequence’. The design was based on their ultrathin U4 Series and the lenses were packaged for either weekly or monthly replacement. |