Scleral Contact Lenses: Clinical Pearls
• DO NOT let corneal scars/opacities/haze deceive you. Just when you think no possible gain in vision could be had with a scleral contact lens, think again. You will be surprised.
• DO NOT discount fitting the elderly. The oldest patient fit to date in our clinic was 95 years old and had no prior contact lens use history. This was a case of extreme dry eyes, reduced correctable vision, and discomfort. She was wildly successful and seen recently on her 2-year follow up — still very pleased with the results.
• DO NOT discount patients who have loss of central vision (e.g., corneal distortions and AMD). Most of these patients will appreciate a gain in peripheral vision.
• DO NOT discount a result of qualitative gain only. A qualitative gain versus a quantitative gain in vision is substantive. Undistorted 20/50 is better than a 20/50 with ghosting and glare.
As successful as corneal transplantation is, post-transplant corneas can have residual distortion, significant levels of higher-order aberrations (HOAs), and irregular astigmatism, limiting correctable vision. The good news: Scleral contact lenses can solve these complex visual issues. (See “Scleral Contact Lenses: Clinical Pearls,” at right.)
Here, I discuss how.
Optics
Scleral contact lenses improve vision in these patients, as they vault over the entire cornea, enabling a saline fluid layer to fill the space between the lens’ concave surface and distorted cornea. This, in turn, effectively neutralizes HOAs and low-order aberrations, thereby improving the visual pathway and resultant acuity. The outcome: The elimination of all, or nearly all, of the symptoms of ghosting, star bursting of lights at night, and glare in post-transplant corneas.
Scleral contact lenses have minimal movement, thereby allowing for the application of toric front-surface optics to correct any residual cylinder and HOAs. Additionally, multifocal, and decentered optics are available.
Recently, an 80-year-old male was referred for management of microbial keratitis (MK). He was left with a dense central scar. Following a very complex path over several years, this patient experienced a penetrating keratoplasty (PKP), a micrograft following a microperforation, two Descemet’s stripping endothelial keratoplasties, cataract surgery, non-healing epithelial defects (resolved with a dehydrated amniotic membrane ap-plied under a scleral contact lens), and IOL expulsion in the setting of open globe trauma. Despite these issues, the patient achieved 20/50 with scleral contact lens application. (Figure 1.)
Figure 1: This patient presented with microbial keratitis, among other issues. Scleral contact lens use resulted in 20/50 vision OU.
Something else to consider: With impression-based scleral devices, prism can be added to a correction. In fact, I recently successfully fit a patient who had post-LASIK ectasia, constant binocular diplopia, and a history of PKP, glaucoma, and retinal detachment repair. Due to residual cylinder post fitting, his final scleral lens parameters were:
OD +3.00-1.62 x130, with 2.5PD Base In and 4PD Base Up; OS +3.00-3.38 x042, with 2.5PD Base In and 4PD Base Down.
The patient reported good correctable vision and no diplopia after fitting.
Comfort
Scleral contact lenses are comfortable due to their inherent design. Gen- erally, they are available in diameters of 14.5 mm to 24 mm. These large diameters keep their edges under the upper and lower lids, thereby creating less lens-edge interaction, resulting in improved comfort. Additionally, the lens edge landing lies on less sensitive scleral tissue versus touching the highly sensitive cornea directly.
Vast improvements in technology and materials over the past decade allow us to customize the lens edge fitting by quadrant of the eye to match the relative flatness or steepness of the globe in a given sector. Consequently, we can alter the shape of the edge to vault over localized pathology, such as a pinguecula or pterygia, or fit over structure, such as glaucoma devices (tubes, shunts, trabeculoplasties, Figure 2).
Figure 2: Note how the scleral contact lens is able to fit over this glaucoma treatment device.
Finally, because the contact lens floats on a layer of saline the entire wearing day, it precludes the discomfort of lens-cornea contact. (See Additional Indications for Scleral Contact Lens Use,” below.)
Final Thoughts
As with all contact lenses, scleral contact lenses are not without limitations. Examples include hypoxia, conjunctival hyperemia, and difficulty with insertion and removal. That said, as illustrated in the cases above, they can be nothing short of amazing and life-altering for those patients who can benefit from them. CP
Additional Indications for Scleral Contact Lens Use
Generally speaking, scleral contact lenses have application in two prominent sectors of ocular pathology:
1. Cases of anterior corneal distortion. These include grafts, trauma, anterior dystrophies, or disease. Example entities: keratoconus, PKP, Salzmann’s nodular degeneration, anterior basement membrane dystrophy, band keratopathy, etc.
2. Ocular surface disease. There is therapeutic value, as well as marked symptom relief and improved vision, for patients who have ocular cicatricial pemphigoid, Stevens-Johnson syndrome, Sjögren’s syndrome, persistent epithelial defects, exposure keratitis, neurotrophic keratitis, etc.
That said, patients who have normal eyes that have an inability to wear unstable toric soft lenses or have high refractive errors also do well with scleral contact lenses.
Additionally, patients who have a normal refractive error, though need hyper-acute vision due to their hobbies, can also achieve success. In fact, I have two patients who drive over 8 hours to be fit with scleral contact lenses with the goal of maximum acute vision for their avocations of competitive rifle shooting.
