Therapeutic Contact Lenses

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Therapeutic Contact Lenses CINDY TROMANS

CHAPTER CONTENTS

Introduction, 477 Indications for Therapeutic Contact Lens Fitting, 477 Lens Types and Selection,  477

Introduction Contact lenses can be used for therapeutic purposes to manage a wide range of ocular conditions. When so fitted, they are referred to as therapeutic contact lenses (TCLs) or bandage lenses. TCLs are fitted mainly to protect or promote healing of the cornea, as well as to provide relief from pain and discomfort. They can range from daily disposable lenses to specialist lenses such as scleral lenses, and although not primarily fitted for refractive correction, this can be incorporated to enhance visual rehabilitation. Development of contact lens materials and modalities and advances in novel technologies such as drug delivery have expanded the scope of TCL practice.

Indications for Therapeutic Contact Lens Fitting The main indications for fitting a therapeutic lens are: pain relief promotion of corneal healing ■ mechanical protection ■ structural support or splint ■ maintaining corneal hydration ■ maintenance of fornices ■ drug delivery. ■ ■

In practice, a combination of these effects may be achieved, but pain relief has been shown to be the most common indication for TCL fitting (Jackson et al. 1996).

Lens Types and Selection All types of contact lens and modality can be considered for therapeutic use, and their fitting is described elsewhere in this book. Selection of an appropriate lens is determined mainly by understanding the primary ocular condition, the indication for fitting and the duration of wear. An ideal lens will address one or more of the indications above and have minimal adverse effects. Factors which need to be considered in the selection of the lens type are discussed in the following sections.

Conditions That Can Benefit from the Use of Therapeutic Contact Lenses,  478 Biological Lenses,  484 Aftercare, 484

Lenses are fitted in the same way as for refractive conditions but extra care is needed to ensure that damage is not caused to an already abnormal ocular surface. Where the eye is particularly painful, instilling a local anaesthetic such as proxymetacaine may be necessary to relax the eye enough to insert the lens. Decide on the best type of TCL to use (see below). Measure the eye to be fitted or if that is not possible, the fellow eye, before selecting the optimum size of lens.

OXYGEN PERMEABILITY The physiological requirements of a diseased eye can be quite different from a normal eye. In many ocular conditions requiring a therapeutic lens, corneal physiology may be affected by damage to the tissues involved in oxygen transport, e.g. endothelial dystrophies. Also, in many applications, the TCL is worn on a continuous-wear basis. In general, the use of materials with greater oxygen permeability is indicated to reduce the degree of hypoxia (Foulks et al. 2003), and silicone hydrogel lenses have become a popular choice for therapeutic use especially when the primary goal is corneal healing. Semi-scleral and scleral lenses are now available in gaspermeable materials, which have increased their therapeutic application.

TEAR FILM AND DISTRIBUTION The tear film and distribution can be affected to varying degrees in diseased eyes. The ocular surface may become irregular, affecting tear distribution, or tear production may be limited. In drier eyes, the wetting angle of the material or tear distribution across the lens will be important in lens selection. In eyes with severe ocular surface disease or exposure, maintenance of a tear reservoir behind the lens to hydrate the cornea will be the main factor for consideration (Pullum & Buckley 2007).

MECHANICAL EFFECTS Fitting a contact lens onto an already diseased eye may produce effects such as low-grade mechanical trauma to the corneal epithelium and the following should be considered: 477

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Adequate lens movement is necessary but, if excessive, it may exacerbate pain and delay healing of the epithelium. ■ With soft lenses, the modulus or ‘stiffness’ of the lens may affect epithelial integrity, with some stiffer silicone hydrogel lenses causing more mechanical trauma to the epithelium. ■ Silicone hydrogel lenses with a higher modulus can be useful for improved visual performance (Simard & Bitton 2008) but may be less comfortable due to the mechanical effect of a stiffer lens on the diseased epithelium. ■ Disposable hydrogel lenses can be useful, particularly for pain relief and promotion of corneal healing as they have a low modulus. They are a low cost option if very frequent replacement or temporary use is required. ■ Semi-scleral and scleral lenses fitted with corneal clearance and limited movement will reduce the mechanical effect on the cornea but the conjunctiva can be compressed or can prolapse (Caroline 2012). ■

(Huang et al. 2009), but the use of a TCL is considered to be an alternative management option when surgery is not an option (Siu et al. 2014). The aim of TCL fitting is to provide pain relief and possible visual improvement, particularly in less severe and recent-onset cases which mainly affect the epithelium (Gasset & Kaufman 1970, Liebowitz & Rosenthal 1971a, Rehim & Samy 1989). Prescription lenses can be fitted to correct the refractive error as well as improve the comfort, for example to aphakic patients (Fig. 26.3) (Speedwell 1991) but where gross stromal oedema and Descemet’s folds are present, the visual improvement is minimal. The guiding parameter is patient comfort, although any neovascularisation in an eye with visual potential may affect the success of a future penetrating keratoplasty. Hence, when choosing a lens, the oxygen transmissibility should be considered. Several studies have described the use of silicone hydrogel lenses for therapeutic purposes in bullous

COVERAGE The total diameter (TD) of the TCL is important to address the main indication for use. The lens should have an appropriate diameter to aid centration and ensure adequate movement but should also cover the affected area when promoting healing and when mechanical protection or maintenance of the fornix is required. For example, when using a soft lens, the TD of the lens should be large enough to cover the limbus completely and provide optimum movement during versions. In some conditions the TD will need to be increased to cover a surgical site or to aid the healing of peripheral or conjunctival lesions (see below). When a lens is required to maintain the fornix, typically a scleral lens, it should be of large enough diameter to prevent the formation of symblepharon.

Fig. 26.1  Bullous keratopathy. (Courtesy of Tony Phillips.)

Conditions That Can Benefit From the Use of Therapeutic Contact Lenses BULLOUS KERATOPATHY Bullous keratopathy is a condition of chronic corneal oedema, caused by endothelial dysfunction, that is characterised by symptoms of pain, epiphora, blepharospasm and photophobia. The cornea is totally or partially involved and appears hazy or opaque due to the severe oedema, which also reduces vision. Small fluid-filled vesicles, known as bullae, form in the epithelium and rupture on the corneal surface (Figs 26.1 and 26.2). The severe pain experienced by patients with this condition is thought to be due to exposure of nerve endings once bullae rupture, or stretching of nerve endings due to acute swelling of the epithelium (Liebowitz & Rosenthal 1971a). Hypertonic saline (5%) can be used initially, but if this is uncomfortable or unsuccessful, TCLs are fitted on a continuous-wear schedule because pain recurs immediately on removal. Penetrating or endothelial keratoplasty can be successfully carried out to treat even advanced bullous keratopathy

Fig. 26.2  Enlarged section of bullous keratopathy showing the individual bullae or blisters. (Courtesy of Tony Phillips.)

Fig. 26.3  Aphakia with bullous keratopathy. This eye was fitted with an extended-wear high–water-content aphakic soft contact lens which acted as a bandage and gave the patient a visual acuity of 6/12. (Courtesy of Lynne Speedwell.)

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keratopathy (Montero et al. 2003, Ambroziak et al. 2004, Ozkurt et al. 2005). Lim & Vogt (2006) compared conventional soft and silicone hydrogel lenses in bullous keratopathy and showed that silicone hydrogels are a safe and effective alternative to conventional soft lenses. Monthly disposable hydrogel lenses or low modulus silicone hydrogel lenses are the first choice of lens but occasionally, a lens with a larger diameter may be needed for larger corneas. A custom-made high water content soft or low modulus silicone hydrogel with a base curve of between 8.00 and 9.50 mm, and a diameter of 15.00 to 16.50 mm can be used.

FUCHS’ ENDOTHELIAL DYSTROPHY Fuchs’ endothelial dystrophy is a slowly progressive disorder characterised by bilateral dysfunction of the corneal endothelium, which leads eventually to corneal oedema and bullous keratopathy. TCLs may be used to relieve pain, often until penetrating keratoplasty can be carried out. The selection and fitting of lenses for Fuchs’ endothelial dystrophy is as described for bullous keratopathy. Kanpolat and Ucakhan (2003) included two cases of Fuchs’ endothelial dystrophy among patients fitted with lotrafilcon A lenses for therapeutic use.

RECURRENT CORNEAL EROSIONS Recurrent corneal erosion (RCE) can occur in many different conditions, including epithelial basement membrane dystrophies (e.g. Cogan’s microcystic dystrophy or map-dotfingerprint dystrophy), but the most common cause is minor trauma to the cornea, which can result in chronic recurrence of the erosion (recurrent erosion syndrome). This can lead to chronic, intermittent attacks of painful epithelial cell loss lasting for several months due to incomplete reformation of the underlying basement membrane. A contact lens allows healing and re-epithelialisation by protecting the delicate regenerating epithelium from the windshield-wiper effect of the lids. Once epithelialisation is complete, the lens allows the epithelial layer to stabilise and provides optimum conditions for hemidesmosomal formation, which can take many months to regenerate completely (Gipson et al. 1989). The lenses therefore need to be worn for long periods to ensure healing is complete, and as epithelial detachment generally occurs during the night or immediately on waking, lenses should be worn on a continuous basis. Soft contact lenses are most usually used in this condition, and hydrogel lenses worn on an extended-wear basis for several months, coupled with copious ocular lubricants, which has been shown to be an effective treatment (Reidy et al. 2000). This has been shown to be a safe and effective treatment with a relatively low recurrence rate after a 3-month period of lens wear (Fraunfelder & Cabezas 2011, Ahad et al. 2013). A therapeutic lens can also be used after delamination of the epithelium in RCEs which have failed to resolve (Dua et al. 2006). This usually takes the form of a phototherapeutic keratectomy or less commonly surgical epithelial debridement. Silicone hydrogel lenses offer the advantage of increased oxygen permeability, which can aid corneal healing. Ambroziak et al. (2004) found that 15 of their 19 cases of

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‘nonhealing’ corneal erosions or postoperative keratoepitheliopathy showed full corneal healing when fitted with silicone hydrogel (lotrafilcon A) lenses. However, once again the modulus of a silicone hydrogel lens can be less comfortable than a hydrogel lens.

THYGESON’S SUPERFICIAL PUNCTATE KERATITIS Thygeson’s superficial punctate keratitis is a rare corneal condition characterised by distinctive central corneal lesions in the absence of conjunctival inflammation. It is generally chronic and typified by periods of exacerbation and remission lasting for weeks or months at a time (Thygeson 1950, Marshall & Holdeman 1992) (Fig. 26.4a and b). It is bilateral and asymmetric, with each eye presenting a different clinical picture at any time (Thygeson 1961). During the active phase of the condition, patients complain of photophobia, foreign-body sensation, tearing and possibly decreased vision, depending on the site of the lesions. Symptoms may be disproportionately severe in relation to the clinical picture. Biomicroscopic examination reveals distinctive stellate or snowflake-like infiltrates in the corneal epithelium. The epithelial surface is raised over the lesions, creating an irregular corneal area that stains incompletely with fluorescein dye. It is this irregularity that results in reduced visual acuity. Patients are asymptomatic during remission, and the corneal lesions appear as flat, faint grey opacities or may be completely absent. Topical corticosteroids are the mainstay of treatment for this chronic condition, but a TCL can relieve symptoms (Nagra et al. 2004) and can also improve the optical characteristics of the irregular corneal surface and hence improve visual acuity (Forstot & Binder 1979, Goldberg et al. 1980). Ultrathin, low water-content hydrogels alleviate symptoms

A

B Fig. 26.4  (a) Thygeson’s superficial punctate keratitis showing corneal infiltrates. (b) These may be elongated rather than round. (a, Courtesy of Tony Phillips; b, Courtesy of Lynne Speedwell.)

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Fig. 26.5  Severe filamentary keratitis. (Courtesy of Tony Phillips.)

(Speedwell 1991), and silicone hydrogels can also prove beneficial (Caroline & Andre 2001).

FILAMENTARY KERATITIS Filamentary keratitis is a condition in which fine threads of mucin and corneal epithelium form. These remain attached at their base to the surrounding epithelium (Fig. 26.5). Symptoms usually consist of foreign-body sensation and pain. It is associated with keratoconjunctivitis sicca, superior limbic keratoconjunctivitis and systemic disorders such as rheumatoid disease (Kowalik & Rakes 1991). The exact cause is unknown, but the filament formation occurs when there is damage to the basal epithelial cells, epithelial basement membrane or Bowman’s layer, with a subsequent focal epithelial basement membrane detachment. This results in a slightly elevated area that acts as a receptor site for mucus produced by the eye, which in turn attracts loose epithelial cells and debris, thus forming a filament (Zaidman et al. 1985). The aim of a TCL is to protect the epithelial surface from the shearing effect of the eyelids and offer protection from further trauma to any damaged areas of epithelial basement membrane. The basal epithelial cells can then reattach to the epithelial basement membrane, preventing the formation of elevated receptor sites for further filament formation. Ocular lubricants are used in conjunction with the lenses, and the lower water content of many silicone hydrogels can prove useful as treatment.

PERSISTENT EPITHELIAL DEFECTS AND STROMAL ULCERATION A persistent epithelial defect (PED) can have numerous different aetiologies, including: bacterial, viral or fungal corneal infections after chemical or thermal burns ■ as a result of poor healing after surgery ■ in association with neuroparalytic keratitis ■ limbal stem cell deficiency. ■ ■

A PED frequently follows herpes simplex virus (HSV), where an epithelial defect results either from a geographic ulcer during the active viral disease or from epithelial breakdown over an area previously damaged by HSV. A PED can also result from toxicity of topical antiviral agents used to treat the underlying infection (McDermott & Chandler 1989).

Fig. 26.6  Indolent corneal ulcer. The patient had been on a cocktail of drops, and the eye had not healed. All drops were stopped, and the cornea was fitted with a silicone hydrogel bandage lens. It healed well and was later fitted with an RGP corneal lens and achieved acuity of 6/12 (0.3 logMAR). (Courtesy of Lynne Speedwell.)

A soft contact lens can be used to protect the epithelium, allowing it to regenerate. However, wearing a soft lens in cases of active HSV can exacerbate the condition, and it can then be difficult to differentiate between lesions from the disease and a PED. Once the condition is quiescent, either rigid or silicone hydrogel lenses can be fitted, although ongoing systemic antiviral treatment may be necessary. Topical treatment of autologus serum in combination with hydrogel bandage lenses (Schrader et al. 2006) and silicone hydrogel lenses (Lee et al. 2016) has been shown to be successful in the management of PEDs from a variety of pathogeneses.

INDOLENT CORNEAL ULCERS A long-standing corneal ulcer that does not heal can improve with the aid of a soft or silicone hydrogel TCL, by protecting the corneal surface from lid trauma and splinting the healing epithelium (Fig. 26.6). This also provides pain relief and allows rapid epithelialisation (Liebowitz & Rosenthal 1971b). A hydrogel lens has been shown to be useful in the management of refractory vernal ulcers, and Quah et al. (2006) describe the use of a large-diameter lens (22 mm) as a shortterm treatment option in children with this condition.

CORNEAL THINNING/PERFORATIONS Corneal perforation can occur from accidental injury or surgical trauma of the cornea or following a persistent epithelial defect after a corneal ulcer. A common cause of corneal thinning is rheumatoid arthritis resulting in keratolysis that destroys the corneal stroma. Where perforation is imminent, a descemetocele often forms (Fig. 26.7), and a therapeutic lens can prevent perforation by reinforcing the cornea and preventing distension of the descemetocele by intraocular pressure. When the cornea thins or perforates, the main aim of therapy is to maintain or restore the corneal integrity so that the anterior chamber either reforms or remains formed. TCLs allow small perforations to heal themselves, provided the wound edges are in good apposition and there is no incarceration or prolapse of the uvea or the crystalline lens. Rehim et al. (1990) reported a high success rate when noninfected perforations, less than 3 mm in size, were treated

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Fig. 26.7  Descemetocele in a failed graft. (Courtesy of Tony Phillips.)

Fig. 26.8  Therapeutic contact lens fitted to protect the surface and lids after glueing a traumatic corneal perforation. The lens remained in situ until the cornea was healed enough. The patient later underwent secondary intraocular lens implantation. (Courtesy of Lynne Speedwell.)

with thin hydrogel lenses worn for 1–2 weeks. Larger perforations were not as successful and generally required surgical repair. However, in the immediate management of large perforations, a contact lens has been shown to be useful to prevent the extrusion of ocular contents and before surgical repair can be performed (Ramjiani et al. 2016). In a peripheral thinning disorder such as Terrien’s marginal degeneration or peripheral ulceration, a large-diameter lens of up to 22 mm may be required to cover the thinned or perforated site (Srinivasan et al. 2006, Papaconstantinou et al. 2009). The use of human fibrin glue (HFG) is now often used to repair a corneal perforation. The quick-drying glue is applied to seal the perforation, and a soft contact lens is placed on the eye once the glue has set (Fig. 26.8). This has been shown to be useful for perforations up to 2 mm and provided fast healing with a low rate of corneal vascularisation (Siatiri et al. 2008). Disposable hydrogel or silicone hydrogel lenses are particularly well suited to this application as the lens is often removed after a few days. The purpose of the lens is both to protect the ‘seal’ from being displaced by the lids and to decrease eyelid irritation from the rough surface of the dried adhesive. The glue usually dissipates, and the lens can be removed prior to repair surgery.

NEUROTROPHIC CONDITIONS Fifth or seventh cranial nerve damage can lead to neurotrophic keratopathy or neuroparalytic keratitis. When damage to the sensory branch of the fifth cranial nerve, for example from a virus, results in an anaesthetic cornea, it can lead to

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Fig. 26.9  Neurotrophic keratopathy. (Courtesy of Tony Phillips.)

neurotrophic keratopathy (Fig. 26.9). The loss of neural influences affects epithelial mitosis that in turn leads to exfoliation and oedema of the corneal epithelium. This can occur even if the blink reflex and lacrimal secretions are normal. Anaesthetic corneas, although requiring protection, are at great risk of abrasions from foreign bodies or irritation from the lens itself. Frequent aftercare and monitoring is therefore vital. In seventh nerve paralysis, incomplete eyelid closure can lead to exposure keratitis that manifests initially as punctate epithelial erosions but can eventually lead to corneal ulceration. Espy (1971) reported that patients with fifth nerve lesions and neurotrophic keratitis could be treated successfully with hydrogel lenses, resulting in complete clearing of epithelial irregularities and associated visual improvement. Sun et al. (2014) reported the use of silicone hydrogel lenses in neurotrophic keratitis and showed a significantly shorter healing time of corneal ulcers. In seventh nerve palsies, a silicone hydrogel lens protects the cornea from drying and is used in conjunction with ocular lubricants. Lenses may be worn on an extended-wear schedule if incomplete lid closure occurs during sleep, or alternatively, complete eye closure can be achieved by taping the lids together at night. If the eye is blind or aphakic, a silicone rubber lens can be used but these lenses are only available in aphakic powers. Rigid gas permeable (RGP) scleral lenses can be fitted which have the advantage of protection whilst the tear reservoir hydrates the cornea and enables corneal surface recovery. They also can enhance visual and social function (Grey et al. 2012, Weyns et al. 2013).

CICATRIZING CONJUNCTIVAL DISEASES In cicatrising conjunctival diseases, TCLs can relieve pain and provide corneal protection from exposure, entropion and trichiasis. They can help maintain the conjunctival fornices in such conditions as ocular pemphigoid (mucous membrane pemphigoid), chemical and thermal burns (Fig. 26.10), trachoma and Stevens-Johnson syndrome (Fig. 26.11) by preventing symblepharon (adhesions between bulbar and palpebral conjunctiva) and ankyloblepharon (fusion of lid margins). All types of lens can be useful in these disorders. Hydrogel or RGP lenses used in association with ocular lubricants offer protection to the cornea from drying, and entropion

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Fig. 26.12  Severe entropion and trichiasis associated with blepharitis. A bandage soft lens allowed regeneration of damaged corneal epithelium and prevented further disturbance prior to surgery. (Courtesy of David Westerhout.)

Fig. 26.10  Chemical burn caused by paraquat. (Courtesy of Tony Phillips.)

Fig. 26.11  Severe ocular surface disease in Stevens-Johnson syndrome fitted with a silicone hydrogel lens.

(Fig. 26.12) and trichiasis (Fig. 26.13), but low–water-content silicone hydrogel lenses may be preferable because they do not need such frequent lubricant drop instillation and the higher oxygen permeability is more suitable for continuous wear. RGP corneo-scleral lenses (Dart 2005) or scleral lenses (Rubinstein 2003, Schornack & Baratz 2009) maintain a good fluid reservoir between the lens and cornea when supplemented with ocular lubricants. They can be used for refractive correction of scarred and irregular eyes and, because they cover most of the ocular surface, they protect both the cornea and conjunctiva while maintaining the fornices. In advanced cases of ocular pemphigoid, symblepharon may prevent the insertion of scleral lenses, and in such cases large-diameter or RGP corneo-scleral lenses can be successful in visual rehabilitation of patients with ocular surface irregularities (Pesudovs & Phillips 1992).

DRY EYE/OCULAR SURFACE DISEASE The Tear Film and Ocular Surface Society (TFOS) Dry Eye WorkShop (DEWS II Definition and Classification subcommittee, 2017) gave the following definition: ‘Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort and visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.’ Inflammation of the lacrimal gland and ocular surface can both cause and result in worsening dry eye disease and is known as keratoconjunctivitis sicca (Fig. 26.14). There is very little

Fig. 26.13  Trichiasis with an RGP prescription lens. The lens sat superiorly on the cornea, thus protecting it from the misaligned lashes. (Courtesy of Lynne Speedwell.)

Fig. 26.14  Keratoconjunctivitis sicca associated with chronic blepharitis. (Courtesy of David Westerhout.)

evidence in the literature to support the use of TCLs in mild dry eye, but the DEWS report recommends that a contact lens be used for treatment of moderate to severe dry eye disease (severity level 3 out of a maximum of 4) in conjunction with autologous serum and permanent punctual occlusion (DEWS 2007) because a contact lens can help protect and hydrate the ocular surface. There are many diseases of the ocular surface that cause severe dry eyes, which would warrant consideration of treatment with a therapeutic lens. These include: Sjögren’s disease toxic epidermal necrolysis ■ Stevens-Johnson syndrome ■ graft-versus-host disease. ■ ■

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A Fig. 26.15  Toxic epidermal necrolysis fitted with a fenestrated PMMA scleral lens. Note the mobile bubble. This gave the patient a visual acuity of 6/24 compared to 3/60 unaided.

Silicone hydrogels have been shown to be useful in the management of discomfort and blurred vision in primary and secondary Sjögren’s disease (Russo et al. 2007, Li at al 2015). However, retention of the lens can be an issue, so a larger-diameter lens may be required. Russo also reported on the use of silicone hydrogel lenses in graft-versus-host disease and again showed an improvement in symptoms, with no adverse events or complications. Modern scleral, corneo-scleral or semi scleral lenses are useful in the management of a severe dry eye in the above conditions (Pullum & Buckley 2007, Stason et al. 2010, Jacobs & Rosenthal 2007, Schornack et al. 2008, Schornack et al. 2014, Sotozono et al. 2014) because they retain a fluid reservoir over the cornea which facilitates both hydration and protection of the corneal surface. The neutralisation of any ocular surface irregularities can also significantly improve visual function (Tougeron-Brousseau et al. 2009). Success with a therapeutic lens in these conditions may require the use of many trial lenses, which can be challenging for patients who are already experiencing significant discomfort. However, a well-fitting lens offers almost immediate improvement in quality of vision and comfort, which in turn can improve the patient’s quality of life (Foulks et al. 2015) (Fig. 26.15).

POSTREFRACTIVE SURGERY Refractive surgery techniques such as photorefractive keratectomy (PRK), laser-assisted in situ keratomileusis (LASIK) and laser-assisted epithelial keratomileusis (LASEK) can result in significant postoperative pain caused by removal of the corneal epithelium. Using a TCL overnight after LASIK has been shown to significantly reduce symptoms during the immediate postoperative period (Orucov et al. 2010). Gil-Cazorla et al. (2008) compared a silicone hydrogel lens and non-silicone hydrogel lens used as a bandage after LASEK and showed that the cornea epithelial status was significantly better in eyes with the silicone hydrogel bandage 5 days after surgery. Taylor et al. (2014) evaluated three different silicone hydrogel lenses (senofilcon A, balafilcon A and lotrafilcon A) used immediately after PRK and showed that senofilcon A caused the least pain. This was not unexpected as it has a much lower modulus than the other two lenses.

B

C Fig. 26.16  (a) Primary care of this corneal wound was carried out at a remote hospital. The corneal surface was grossly irregular and the suture ends exposed. (b) A bandage lens was used for comfort. (c) When the cornea had healed and the inflammation settled, keratoplasty was performed with good results. (Courtesy of Doug Coster.)

OTHER SURGICAL PROCEDURES Soft therapeutic lenses can be used to assist epithelial healing, to protect the eyelids from suture ends (Fig. 26.16), to reduce pain and to seal a surgical wound site. Various postsurgical complications can be managed with therapeutic lenses, including: wound dehiscence leaking blebs after trabeculectomy ■ pterygium surgery ■ Boston keratoprosthesis (K-Pro) (see Chapter 22) ■ stem cell grafts ■ removal of calcium in band keratopathy ■ corneal cross-linking. ■ ■

The main factors to be considered for the lens are size, oxygen permeability and modulus. Larger-diameter lenses (up to 22 mm) may be needed to treat a leaking bleb (Wu et al. 2015) and post-pterygium surgery (Arenas & Garcia 2007, Daglioglu et al. 2014), as the wound extends beyond

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the limbus. Lenses of 19 or 20 mm diameter are required for long-term use after K-Pro surgery to drape over the device and protect both the device and the lids (Nau et al. 2014) (see Chapter 22, Fig. 22.28a). This can be made in tinted format to improve cosmesis (see Fig. 22.28b). A large-diameter (16.5 mm TD) silicone hydrogel lens offers greater oxygen permeability and also a stiffer modulus, which is useful in the conservative treatment of wound dehiscence after penetrating keratoplasty, where there is risk of graft rejection (Ugarte & Falcon 2006).

DRUG DELIVERY (see Chapter 27) Contact lenses for drug delivery is an area which has attracted much interest, as conventional eye drop therapy has low bioavailability to target ocular tissues due to issues with precorneal drug-loss factors, e.g. lacrimation and blinking, naso-lacrimal drainage, as well as poor absorption through the conjunctiva and variable compliance. TCLs have been proposed for controlled and sustained drug delivery due to their unique properties because they deliver more than 50% bioavailability to the eye compared with approximately 5% with eye drop formulations (Kuan-Hui et al. 2014). Different methodologies have been used to develop therapeutic lenses, including: soaking molecular imprinting ■ colloidal nanoparticles ■ use of vitamin E ■ supercritical fluid technology. ■ ■

Maulvi et al. (2016) provides a detailed review of all of the above methods but states that whilst therapeutic lenses are an excellent alternative to treat chronic ocular diseases, the commercialisation of such products is still limited. Researchers still need to address the issues that affect critical lens properties in comfortable extended wear, such as transparency, mechanical properties, water content, ion and oxygen permeability. Once these issues are resolved, the TCL used for drug delivery may change the way ocular diseases are treated.

Biological Lenses Therapeutic or bandage lenses made from biological tissues such as collagen were developed for protection of the ocular surface and to promote healing. Also known as a collagen shield, the lenses are manufactured from porcine or bovine collagen. They dissolve over a period of 24 hours, and they have been suggested as a drug delivery device by soaking the lens in a pharmacological agent with adjunctive topical treatment (Willoughby et al. 2002). However, advances in both hydrogel and silicone materials and modalities have largely negated the need for the use of this type of lens, which is no longer commercially available. Amniotic membrane transplants have been used to treat ocular surface disease in conditions such as StevensJohnson syndrome and toxic epidermal necrolysis, as well as after surgical procedures such as pterygium removal, where there is a resultant large defect in the cornea. Amniotic membrane has natural therapeutic properties which

promote the healing of damaged ocular surfaces. Typically, this involves surgical attachment of the membrane to the ocular surface. One technique involves attachment of the amniotic membrane with a custom-made forniceal ring (Ma et al. 2016). Prokera® is a disc of amniotic membrane fastened to an ophthalmic conformer that can be inserted like a contact lens. Other lenses like this may make the use of therapeutic biological contact lenses more common in the future.

Aftercare A TCL wearer is prone to all complications associated with contact lens wear (see Chapter 17) but is also disposed to more common problems such as blepharitis, and serious problems such as microbial keratitis, even with silicone hydrogel lenses (Saini et al. 2013). Patients requiring TCLs are often managed by a multidisciplinary team in a secondary or tertiary healthcare setting but they should be reviewed more frequently than normal contact lens wearers. Initial follow up should be 1-3 days after lens fitting, then 2-3 weeks later, before a regular aftercare schedule is organised. Patients must be warned of the risks of continuous wear and advised to attend urgently should they experience any unusual redness, discomfort, reduced vision or pain. Lens loss can also be an issue, and in cases where the TCL is providing pain relief or protection of the ocular surface, rapid replacement or refitting of the TCL is required. Where possible, spare lenses should be available. If standard disposable lenses are used, spares can also be given to the patient or their carer to have for emergency. (see also the TCL Information Sheet available at: https:// expertconsult.inkling.com/.)

References Ahad, M.A., Anadan, M., Tah, V., et al., 2013. Randomized controlled study of ocular lubrication versus bandage contact lens in the primary treatment of recurrent corneal erosion syndrome. Cornea 32, 1311–1314. Ambroziak, A.A., Szaflik, J.P., Szaflik, J., 2004. Therapeutic use of a silicone hydrogel contact lens in selected clinical cases. Eye Contact Lens 30, 63–67. Arenas, E., Garcia, S., 2007. A scleral soft contact lens designed for the postoperative management of pterygium surgery. Eye Contact Lens 33, 9–12. Caroline, P.J., 2012. Conjunctival prolapse, hooding, chalasis or. … Contact Lens Spectr. 27, 56. Caroline, P.J., Andre, M.P., 2001. When the eye needs a bandage. Contact Lens Spectr. 16, 56. Craig, J.P., Nichols, K.K., et al., 2017. TFOS DEWS II Definition and Classification Report. Ocul. Surf. 15, 276–283. Daglioglu, M.C., Coskun, M., Ilhan, N., et al., 2014. The effects of soft contact lens use on the cornea and patient’s recovery after autograft pterygium surgery. Cont. Lens Anterior Eye 37, 175–177. Dart, J., 2005. Cicatricial pemphigoid and dry eye. Semin Ophthalmol 20, 95–100. DEWS 2007. Management and therapy of dry eye: report of the Subcommittee on Management and Therapy of Dry Eye Disease. Ocul. Surf. 5, 163–178 [Level III]. Dua, H.S., Lagnado, R., Raj, D., et al., 2006. Alcohol delamination of the corneal epithelium: an alternative in the management of recurrent corneal erosions. Ophthalmology 113, 404–411. Espy, J.W., 1971. Management of corneal problems with hydrophilic contact lenses. Am. J. Ophthalmol. 72, 521–526. Forstot, S.L., Binder, P.B., 1979. Treatment of Thygeson’s superficial punctate keratopathy with soft contact lenses. Am. J. Ophthalmol. 88, 186–189.

26  •  Therapeutic Contact Lenses Foulks, G.N., Forstott, S.L., Donshik, P.C., et al., 2015. Clinical guidelines for the management of dry eye associated with Sjogren disease. Ocul. Surf. 13, 118–132. Foulks, G.N., Harvey, T., Raj, C.V., 2003. Therapeutic contact lenses: the role of high-Dk lenses. Ophthalmol. Clin. North Am. 16, 455–461. Fraunfelder, F.W., Cabezas, M., 2011. Treatment of recurrent corneal erosion by extended wear bandage contact lens. Cornea 30, 164–166. Gasset, A.R., Kaufman, H.E., 1970. Therapeutic uses of hydrophilic contact lenses. Am. J. Ophthalmol. 69, 252–259. Gil-Cazorla, R., Teus, M.A., Arranz-Márquez, E., 2008. Comparison of silicone and non-silicone hydrogel soft contact lenses used as a bandage after LASEK. J. Refract. Surg. 24, 199–203. Gipson, I.K., Spurr-Michaud, S., Tisdale, A., et al., 1989. Reassembly of the anchoring structures of the corneal epithelium during wound repair in the rabbit. Invest. Ophthalmol. Vis. Sci. 30, 425–434. Goldberg, D.B., Schanzlin, D.J., Brown, I., 1980. Management of Thygeson’s superficial punctate keratitis. Am. J. Ophthalmol. 89, 22–24. Grey, F., Carley, F., Biswas, S., et al., 2012. Scleral contact lens management of bilateral exposure and neurotrophic keratopathy. Cont. Lens Anterior Eye 35, 288–291. Huang, T., Wang, Y., Gao, N., et al., 2009. Complex deep lamellar endothelial keratoplasty for complex bullous keratopathy with severe vision loss. Cornea 28 (2), 157–162. Jackson, A.J., Sinton, J.E., Frazer, D.G., et al., 1996. Therapeutic contact lenses and their use in anterior segment pathology. J. Br. Contact Lens Assoc. 19, 11–19. Jacobs, D.S., Rosenthal, P.B., 2007. Boston scleral lens prosthetic device for treatment of severe dry eye in chronic graft versus host disease. Cornea 26, 1195–1199. Kanpolat, A., Ucakhan, O.O., 2003. Therapeutic use of Focus Night & Day contact lenses. Cornea 22, 726–734. Kowalik, B.M., Rakes, J.A., 1991. Filamentary keratitis – the clinical challenges. J. Am. Optom. Assoc. 62, 200–204. Kuan-Hui, H., Gause, S., Chauhan, A., 2014. Review of ophthalmic drug delivery by contact lenses. J. Drug Deliv. Sci. Technol. 24 (2), 123–135. Lee, Y.K., Lin, Y.C., Tsai, S.H., et al., 2016. Therapeutic outcomes of combined topical autologous serum eye drops with silicone-hydrogel soft contact lensesin the treatment of corneal persistent epithelial defects: A preliminary study. A preliminary study. Contact lens and Anterior Eye 39, 425–430. Li, J., Zhang, X., Zheng, Q., et al., 2015. Comparative evaluation of silicone hydrogel lenses for the management of Sjogren Syndrome associated dry eye. Cornea 34, 1072–1078. Liebowitz, H.M., Rosenthal, P., 1971a. Hydrophilic contact lenses in corneal disease. II. Bullous keratopathy. Arch. Ophthalmol. 85, 283–285. Liebowitz, H.M., Rosenthal, P., 1971b. Hydrophilic contact lenses in corneal disease. I. Superficial, sterile, indolent ulcers. Arch. Ophthalmol. 85, 163–166. Lim, N., Vogt, U., 2006. Comparison of conventional and silicone hydrogel contact lenses for bullous keratopathy. Eye Contact Lens 32, 250–253. Ma, K.N., Thanos, A., Chodosh, J., et al., 2016. A novel technique for amniotic membrane transplantation in patients with acute Stevens-Johnson syndrome. Ocul. Surf. 14, 31–36. Marshall, W.L., Holdeman, N.R., 1992. Thygeson’s superficial punctate keratopathy: a case report. Clin. Eye Vis. Care 4, 151–154. Maulvi, F.A., Tejal, G., Shah, D.O., 2016. A review on therapeutic contact lenses for drug delivery. Drug Deliv. 29, 1–10. McDermott, M.L., Chandler, J.W., 1989. Therapeutic use of contact lenses. Surv. Ophthalmol. 33, 381–394. Montero, J., Sparholt, J., Mély, R., et al., 2003. Retrospective case series of therapeutic applications of Lotrafilcon A silicone hydrogel soft contact lenses. Eye Contact Lens 29, 72–75. Nagra, P.K., Rapuano, C.J., Cohen, E.J., et al., 2004. Thygeson’s superficial punctate keratitis: ten years’ experience. Ophthalmology 111, 34–37. Nau, A.C., Drexler, S., Dhaliwal, D.K., et al., 2014. Contact lens fitting and long term management for the Boston keratoprosthesis. Eye Contact Lens 40, 185–189. Orucov, F., Frucht-Perry, J., Raiskup, F.D., et al., 2010. Quantitative assessment of soft contact lens wear immediately after LASIK. J. Refract. Surg. 26, 744–748. Ozkurt, Y., Rodop, O., Oral, Y., et al., 2005. Therapeutic applications of lotrafilcon a silicone hydrogel soft contact lenses. Eye Contact Lens 31, 268–269. Papaconstantinou, D., Georgopoulos, G., Kalantzis, G., et al., 2009. Peripheral ulcerative keratitis after trabeculectomy in a patient with rheumatoid arthritis. Cornea 28, 111–113.

485

Pesudovs, K., Phillips, A.J., 1992. The use of a rigid gas permeable lens in ocular cicatricial pemphigoid. Clin. Exp. Optom. 75, 188–191. Pullum, K., Buckley, R.J., 2007. Therapeutic and ocular surface indications for scleral lenses. Ocul. Surf. 5, 40–48. Quah, S.A., Hemmerdinger, C., Nicholson, S., et al., 2006. Treatment of refractory corneal ulcers with large-diameter bandage contact lenses. Eye Contact Lens 32, 245–247. Ramjiani, V., Fearnley, T., Tan, J., 2016. A bandage lens prevents extrusion of ocular contents. Cont. Lens Anterior Eye 39, 78–79. Rehim, M.H.A., Samy, M., 1989. The role of therapeutic soft contact lenses in treatment of bullous keratopathy. Contact Lens J. 17, 119–125. Rehim, M.H.A., Shafik, M.A.A., Samy, M., 1990. Management of corneal perforation by therapeutic contact lenses. Contact Lens J. 18, 107–111. Reidy, J.J., Paulus, M.P., Gona, S., 2000. Recurrent erosions of the cornea: epidemiology and treatment. Cornea 17, 767–772. Rubinstein, M., 2003. Applications of contact lens devices in the management of corneal disease. Eye (Lond) 17, 872–876. Russo, P.A., Bouchard, C.S., Galasso, J.M., 2007. Extended wear silicone hydrogel soft contact lenses in the management of moderate to severe dry eye signs and symptoms secondary to graft-versus-host disease. Eye Contact Lens 33, 144–147. Saini, A., Rapuano, C.J., Laibson, P.R., et al., 2013. Episodes of microbial keratitis with therapeutic silicone hydrogel bandage soft contact lenses. Eye Contact Lens 39, 324–328. Schornack, M., Baratz, K., Patel, S., et al., 2008. Jupiter scleral lens in the management of graft versus host disease. Eye Contact Lens 34, 302–305. Schornack, M.M., Baratz, K.H., 2009. Ocular cicatricial pemphigoid: the role of scleral lenses in disease management. Cornea 28, 1170–1172. Schornack, M.M., Pyle, J., Patel, S.V., 2014. Scleral lenses in the management of ocular surface disease. Ophthalmology 121, 1398–1405. Schrader, S., Wedel, T., Moll, R., et al., 2006. Combination of serum eye drops with hydrogel bandage contact lenses in the treatment of persistent epithelial defects. Graefes Arch. Clin. Exp. Ophthalmol. 244, 1345–1349. Siatiri, H., Moghimi, S., Malihi, M., et al., 2008. Use of sealant (HFG) in corneal perforations. Cornea 27, 988–991. Simard, P., Bitton, E., 2008. The use of high modulus silicone hydrogel (SiHy) lens in the management of epithelial defects. Cont. Lens Anterior Eye 31, 154–157. Siu, G.D., Young, A.L., Jhangi, V., 2014. Alternatives to corneal transplantation for the management of bullous keratopathy. Curr. Opin. Ophthalmol. 25, 347–352. Sotozono, C., Yamauchi, N., Maeda, S., et al., 2014. Tear exchangeable limbal rigid contact lens for ocular sequelae resulting from Stevens-Johnson syndrome or toxic epidermal necrolysis. Am. J. Ophthalmol. 158, 983–993. Speedwell, L., 1991. A review of therapeutic lenses. Optician 202, 25–30. Srinivasan, S., Murphy, C.C., Fisher, A.C., et al., 2006. Terrien’s marginal degeneration presenting with spontaneous corneal perforation. Cornea 25, 977–980. Stason, W.B., Razavi, M., Jacobs, D.S., et al., 2010. Clinical benefits of the Boston Ocular Surface prosthesis. Am. J. Ophthalmol. 149, 54–61. Sun, Y.Z., Guo, L., Zhang, F.S., 2014. Curative effect assessment of bandage contact lens in neurogenic keratitis. Int. J. Ophthalmol. 7, 980–983. Taylor, R., Caldwell, M.C., Payne, A.M., et al., 2014. Comparison of 3 silicone hydrogel bandage soft lenses for pain control after photorefractive keratectomy. J. Cataract Refract. Surg. 40, 1798–1804. Thygeson, P., 1950. Superficial punctate keratitis. J. Am. Med. Assoc. 18, 1544–1549. Thygeson, P., 1961. Further observations of superficial punctate keratitis. Arch. Ophthalmol. 66, 34–38. Tougeron-Brousseau, B., Dedcampe, A., Guendary, J., et al., 2009. Vision related function after scleral lens fitting in ocular complications of Stevens-Johnson syndrome and toxic epidermal necrolysis. Am. J. Ophthalmol. 148, 852–859. Ugarte, M., Falcon, M.G., 2006. Spontaneous wound dehiscence after removal of a single continuous penetrating keratoplasty suture: conservative management. Cornea 25, 1260–1261. Weyns, M., Koppen, C., Tassignonn, M.J., 2013. Scleral contact lenses as an alternative to tarsorrhaphy for the long term management of combined exposure and neurotrophic keratopathy. Cornea 32, 359–361. Willoughby, C.E., Batterbury, M., Kaye, S.B., 2002. Collagen corneal shields. Surv. Ophthalmol. 4, 174–182. Wu, Z., Huang, C., Huang, Y., et al., 2015. Soft bandage contact lenses in the management of early bleb leak following trabeculectomy. Eye Sci. 30, 13–17. Zaidman, G.W., Geeraets, R., Paylor, R.R., et al., 1985. The histopathology of filamentary keratitis. Arch. Ophthalmol. 103, 1178–1181.