FOR DOCTORS

erry Rosenthal, M.D., founder of the Contact Lens Service, Massachusetts Eye and Ear Infirmary and assistant clinical professor of ophthalmology, Harvard Medical School, has developed a family of unique contact lens devices designed to rehabilitate the impaired vision of eyes with irregular corneal astigmatism that are intolerant of rigid corneal contact lenses. Its fluid reservoire also functions as a unique liquid corneal bandage that adds a new dimension to the management of severe ocular surface disease. The product of 15 years of research that combines the elements of advanced polymer chemistry, digital lens design and state-of-the-art computerized manufacturing technology, its flagship vision-restoring device, the fluid-ventilated gas permeable Boston Scleral Lens was approved by the FDA in 1994 for the management of corneal disorders and has achieved a success rate exceeding 90% in more than 800 patients. To reach the hundreds of thousands of people world-wide who could benefit from its developments, our 501 (C)3 nonprofit foundation, supported by a major Gift of Sight grant from Johnson & Johnson has developed a three-year plan to establish this technology in academic eye-care centers in the U.S. and abroad from its base in Needham, Massachusetts.

The Need

We estimate there are hundreds of thousands of patients suffering from corneal disorders in the U.S. alone who can benefit from the Foundation's lenses today.
The vast majority of our patients are young-some are children. More than half have exhausted all other available treatment options. The Boston Scleral Lens is their only hope for regaining function vision. For the remaining patients, our lenses replace the need for corneal transplant surgery.

THE BOSTON FOUNDATION FOR SIGHT
501(c)3 nonprofit

Mission: To make the Boston Scleral Lens available to all whom it can help regardless of their ability to pay.

What is the Boston Scleral Lens?
The Boston Scleral Lens Prosthetic Device (BSLPD) is the first fluid-ventilated scleral lens designed to enclose a bubble-free reservoir of oxygenated aqueous fluid maintained it at neutral hydrostatic pressure over the corneal surface. By avoiding the intrusion of air bubbles, its fluid reservoir functions as a liquid corneal bandage that offers unique therapeutic benefits for managing severe ocular surface disease in addition to its traditional role of masking irregular corneal astigmatism. The BSLPD was approved by the FDA for the management of corneal disorders in 1994.

How does its fluid-ventilated design work?
The principle feature of this design is a series of breaches created between the haptic bearing surface of the lens and the underlying sclera designed to facilitate the aspiration of surface tears into the fluid reservoir as the means of avoiding suction when the lens decompresses after each blink. In order to maintain their functionality and prevent the intrusion of air bubbles, the shape of the haptic bearing surface must conform to that of the underlying sclera. This has been facilitated by the Foundation’s powerful design software program that incorporates spline functions to create inherently junctionless surfaces. The Foundation’s lens design software program models each eye-specific scleral lens on a desktop computer and offers the fitter unequalled freedom to manipulate its shape. The data is compiled automatically and transmitted to the operating system of our high-precision digital lathe. This system provides unequalled flexibility in customizing the design of each lens.

Who can be helped by the Boston Scleral Lens?
Indication 1: masking corneal astigmatism inadequately corrected with spectacle lenses and intolerant of RGP corneal contact lenses. These disorders include corneal ectasia (keratoconus, keratoglobus, pellucid marginal degeneration, Terrien’s marginal degeneration), complications of keratorefractive procedures, abnormal astigmatism following PKP, corneal scars, certain anterior cornea dystrophies etc.

Indication 2: As a corneal liquid bandage in the management of severe ocular surface diseases that have not responded adequately to all other treatment regimens such as intensive lubrication, bandage soft lenses, topical cyclosporin and punctal occlusion. It has replaced the need for and has been more effective than extensive tarsorrhaphy in corneal disorders such as corneal stem cell deficiency (Stevens-Johnson syndrome/TEN, chemical/thermal injuries including surgical procedures, aniridia, ocular pemphigoid, idiopathic), neurotrophic corneas (congenital and acquired), severe dry eye (Sjogren’s syndrome, chronic graft versus host disease, etc.) and those associated with systemic autoimmune diseases (rheumatoid arthritis, dermatological disorders such as atopic, epidermolysis bullosa, epidermal dysplasia) and corneal exposure.

Limitations and contraindications
Despite its high oxygen transmissibility (XO Polymer Technology Corp. Dk 100 ANSI-FATT units, average center thickness 0.16mm), their corneal tolerance requires adequate endothelial function because of their limbus-to-limbus coverage. Preexisting microcystic corneal edema will be intensified during lens wear. Eyes that have undergone PKP or those with endothelial disease and no evidence of epithelial edema are deliberately stressed during the screening process and their corneal center thickness is monitored to confirm the availability of adequate functional endothelial reserve. Failing grafts do not do well with scleral lenses.

Residual high order aberrations (typical of corneal ectasia or that occur following laser keratorefractive procedures) may compromise vision hard contact lens-corrected vision to some degree and this factor is weighed during the screening trial.

Patient Qualifications
The empirical process of custom fitting each device is costly, time-consuming and skill-intensive. Insertion/ removal are awkward and inconvenient and can require many hours of training to master. The care regimen is more costly and some patients (especially those with severe dry eye) may need to replace the fluid reservoir periodically if it accumulates debris sufficient to compromise vision. Moreover, as a 501(c)(3) nonprofit, we are committed to treat all patients who can benefit from our device regardless of their ability to pay. For these reasons we are rigorous in enforcing the following requirements:
• Doctor referral is mandatory.
• Significant disability inadequately responsive to all other available low-risk treatment regimens.
• Convincing evidence of the effectiveness of our device as determined by the patient’s response to a wearing trial during the consultation and wearing trial.

The pre-fitting process
This is divided into three segments.
• Review of referral information: This may include communication with the referring doctor and patient to determine, to the degree possible, whether the patient qualifies for the Boston Scleral Lens.
• Consultation: The objective of this examination is to rule out contraindications and determine whether there is sufficient potential benefit to proceed to the next step. Patient expectations are explored and goals, mutually agreed to by the patient and doctor are established.
• Screening trial: Its purpose is to assess the likelihood of the goals being satisfied and to asses the physiological corneal response (primarily for corneas following PKP and those with endothelial disease). The process involves the selection of an appropriate lens for each eye and evaluating its performance after it is worn for at least four hours. If an acceptable trial lens is not available in our existing library of over 300 devices and one needs to be fabricated, the procedure may require a second day to complete the assessment.

The fitting process
This is initiated only if the results of the screening trial meet the goals of both the patient and doctors. Our onsite laboratory enables lenses to be designed and delivered in 45 minutes, greatly facilitating the fitting process for our out-of-town patients.
• The BSLPD is custom designed for each eye through a trial-and-error iterative process. When a newly inserted trial lens satisfies certain established fitting criteria, it is worn for several hours and its fitting characteristics are evaluated. Its design is then manipulated through our CAD/CAM program, the lens is fabricated and its fitting characteristics are evaluated. This is process is repeated until the optimal fit and vision correction is achieved. Eyes that have unusually distorted, features such as seen in Stevens-Johnson syndrome, may require the fabrication of numerous devices in order to achieve the optimal design.
• Insertion/removal training is scheduled at appropriate intervals during the fitting process. The procedure is awkward and may be especially challenging for patients with no prior contact lens experience or whose eyes are painful and photophobic. The care regimen is also more time-consuming and of greater importance than that for conventional contact lenses in order to minimize the risk of bacterial infection especially in eyes with severe ocular surface disease.

What patients will want to know
The cost and insurance coverage:
• The global fee is $7,600 for two eyes and $5,000 for one eye. This includes all visits and lenses that need to be fabricated (averages 3.5 /eye but may require up to 10 or more/eye) for up to 6 months.
• Massachusetts BlueCross BlueShield, Tufts Health Plan and Harvard Pilgrim cover the full fitting cost without requiring pre-approval. Other health insurers are following their lead. We aggressively pursue all appeals on denials. Well over 50% of health insurers eventually agree to cover the full costs. Medicare (DMERC) pays for the lens portion of the cost but not, as yet, the fitting fee.
• Qualifications for free and subsidized care are based on a means application.
• The fitting/training process requires patients to be available for a minimum of five days but they should be prepared to stay longer. Those with scarred bulbar conjunctiva (such as SJS) may require up to three weeks. In some patients, the time required to master insertion/removal determines their length of stay.
• The local Needham Sheraton Hotel offers discounted rates for our patients and provides a shuttle service to and from our clinic. There are, also, a number of hospitality homes that are available to patients free of charge.

References
1. Schein OD, Rosenthal P, Ducharme C. A gas-permeable scleral contact lens for visual rehabilitation. Am J Ophthalmol 1990; 109:318.
2. Rosenthal, P., Cotter, J.M. Treatment of persistent epithelial defect with extended wear of a fluid-ventilated gas permeable scleral contact lens. Am J Ophthalmol 2000; 130: 33-41.
3. Romero-Rangel, T, Stavrou, P, Cotter, J, Rosenthal, P, Foster, S. Gas permeable scleral lens therapy in ocular surface disease. Am J Ophthalmol 2000; 130:25-32.
4. Rosenthal P, Cotter JM. The Boston Scleral Lens in the Management of Severe Ocular Surface Disease. In: Foulks, G, ed. Ophthalmol Clin N.Am 16 2003 89-93.
5. Rosenthal, P., Croteau, A. Fluid-Ventilated, Gas-Permeable Scleral Contact Lens Is an effective Option for Managing Severe Ocular Surface Disease and Many corneal Disorders That Would Otherwise require Penetrating Keratoplasty. Eye & Contact Lens; 2005; 31 (3) (130-134).
6. Rosenthal P, Cotter JM. The Boston Scleral Lens in the Management of Severe Ocular Surface Disease. In: Foulks, G, ed. Ophthalmol Clin N.Am 16 2003 89-93
7.Rosenthal P, Jacobs, D, Johns, L. Fluid-ventilated gas permeable scleral lens: a new paradigm for the management of irregular corneal astigmatism and severe ocular surface disease. Contemporary Ophthalmology 2006, 5 (22)

Doctor's Guide to
The Boston Scleral Lens Prosthetic Device
(PDF Download)

New for Doctors
Design and Fitting Principals of the Boston Scleral Lens Prosthesis !

Use of Fluid-Ventilated, Gas-Permeable Scleral Lens
for Management of Severe Keratoconjunctivitis Sicca
Secondary to Chronic Graft-versus-Host Disease

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