ARTICLE
Scleral Lenses in the Management of Keratoconus Muriel M. Schornack, O.D., and Sanjay V. Patel, M.D.
Purpose: To describe the use of Jupiter scleral lenses (Medlens Innovations, Front Royal, VA; and Essilor Contact Lenses, Inc., Dallas, TX) in the management of keratoconus. Methods: We performed a single-center retrospective chart review of our initial 32 patients with keratoconus evaluated for scleral lens wear. All patients were referred for scleral lens evaluation after exhausting other nonsurgical options for visual correction. Diagnostic lenses were used in the initial fitting process. If adequate fit could not be achieved with standard lenses, custom lenses were designed in consultation with the manufacturers’ specialists. The following measures were evaluated for each patient: ability to tolerate and handle lenses, visual acuity with scleral lenses, number of lenses, and visits needed to complete the fitting process. Results: Fifty-two eyes of 32 patients were evaluated for scleral lens wear. Of these, 12 patients (20 eyes) decided not to pursue scleral lens wear after initial evaluation. One patient (2 eyes) abandoned the fitting process after cataract surgery. The remaining 19 patients (30 eyes) were fit successfully. The average number of lenses ordered per eye was 1.5. The fitting process required an average of 2.8 visits. Standard lenses were prescribed for 23 eyes, and custom designs were needed for 7 eyes. Median best-corrected visual acuity improved from 20/40 (mean, 20/76) before scleral lens fitting to 20/20 (mean, 20/30) after fitting. Follow-up ranged from 3 to 32 months. Conclusions: Jupiter scleral lenses provide acceptable visual acuity and comfort in patients with keratoconus. The availability of diagnostic lenses facilitates the fitting process. Key Words: Keratoconus—Scleral contact lenses—Visual acuity—Ectasia. (Eye & Contact Lens 2010;1: 39⫺44)
K
eratoconus is a noninflammatory, ectatic corneal disorder characterized by progressive thinning and distortion of the apical cornea. The condition is bilateral but frequently asymmetric.1 Visual acuity in patients with keratoconus may be compromised because of either irregular astigmatism or corneal scarring.2 Kennedy et al. reported that the prevalence of keratoconus was 55 per 100,000 population; they also found that the probability of survivorship without corneal transplantation for 20 years beyond initial diagnosis was approximately 80%.3
From the Department of Ophthalmology, Mayo Clinic, Rochester, MN. Supported by Research to Prevent Blindness Inc., New York, NY (an unrestricted grant to the Department of Ophthalmology, and SVP as Olga Keith Wiess Special Scholar), and Mayo Foundation, Rochester, MN. The authors have no financial interest in the products or manufacturers described. Address correspondence and reprint requests to Muriel M. Schornack, O.D., Department of Ophthalmology, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905; e-mail:
[email protected] Accepted October 23, 2009. DOI: 10.1097/ICL.0b013e3181c786a6
Eye & Contact Lens • Volume 36, Number 1, January 2010
Management of patients with keratoconus consists primarily of providing optical correction to maximize visual function. In very mild or early disease, spectacle correction or standard hydrogel or silicone hydrogel lenses may provide adequate vision. However, disease progression results in increasing ectasia, which gives rise to complex optical aberrations. Rigid gas-permeable contact lenses mask these aberrations by allowing a tear lens to form between the contact lens and the irregular corneal surface. Zadnik et al. found that 65% of patients who enrolled in the Collaborative Longitudinal Evaluation of Keratoconus study were wearing rigid gaspermeable lenses in one or both eyes at the time of enrollment.4 Despite their optical benefit, corneal rigid gas-permeable lenses may not be appropriate for all patients with keratoconus. In advanced cases, surface irregularity may increase the likelihood of significant lens decentration or even dislocation, and some patients cannot adapt to the lens sensation induced by standard corneal lenses. Other patients live or work in dry or dusty environments that are not conducive to corneal rigid gas-permeable lens wear. Piggyback lens systems or hybrid lenses may provide adequate comfort in some of these patients, but they also increase the complexity and cost of lens wear and storage. In addition to presenting fitting and adaptation challenges, corneal rigid gas-permeable lenses may be associated with an increased risk of corneal scarring in patients with keratoconus.5–7 The use of large-diameter “contact shells” in the management of keratoconus was initially described by Kalt in 1888,8 at approximately the same time as Mueller9 and Fick10 were describing their experiments with blown glass shells. Manufacturing challenges and complete lack of oxygen permeability of these early lenses limited their use. The development of computer-assisted manufacturing processes and the introduction of gas-permeable contact lens materials have led to a resurgence of interest in large-diameter lens designs, and several authors have described the use of scleral rigid gas-permeable lenses for the management of keratoconus.11–16 At Mayo Clinic, we began using Jupiter (Medlens Innovations, Front Royal, VA; and Essilor Contact Lens, Inc., Dallas, TX) scleral lenses in June 2006. We fit lenses by using the 18.2-mmdiameter diagnostic lens series (manufactured by Medlens Innovations), which includes standard and keratoconus designs. This study describes our initial experience with Jupiter scleral lenses in the management of keratoconus and highlights the relative ease, efficiency, and efficacy of fitting these large-diameter lenses.
MATERIALS AND METHODS During the period of this study (June 2006 through November 2008), we evaluated 209 patients for possible scleral lens wear. Of all patients evaluated for scleral lens wear, 32 (15%) had keratoconus. All the patients with keratoconus referred to us reported some level of dissatisfaction with vision or comfort with their current 39
M.M. Schornack and S.V. Patel
Eye & Contact Lens • Volume 36, Number 1, January 2010
FIG. 1. Scleral lens in situ on an eye with keratoconus. The lens rests on the sclera without conjunctival blanching and vaults the cornea from limbus to limbus. Because the lens extends into the fornices, minimal discomfort is generated from interaction with the eyelids.
mode of correction. These patients represent the first patients with keratoconus evaluated in Mayo Clinic’s scleral lens practice. Because appropriate sagittal depth is more important than alignment with the central cornea in scleral lens fitting, selection of the initial diagnostic scleral lens differs from initial lens selection for corneal lens fitting. As of yet, no specific fitting guidelines for scleral lenses have been validated or published. The fitting guide provided by Medlens Innovations for Jupiter lenses suggests that the base curve of the initial diagnostic lens should be approximately 1 diopter steeper than the steepest corneal curve. Consultants at Essilor suggest that the reference sphere from the elevation map generated by a corneal topographer may be the most appropriate starting point for diagnostic scleral lens fitting. Before fitting scleral lenses, we obtained topographic images on all patients except one (2 eyes); simulated keratometry was recorded unless the corneal surface was too irregular to provide meaningful videokeratoscopic data (11 eyes). Reference sphere was also recorded for all eyes for which topographic images were obtained. We based our initial diagnostic lens selection on the reference sphere and external observation of the profile of the anterior corneal surface. We used 18.2-mm-diameter diagnostic lenses for all patients in this series. Fitting goals for scleral lenses included scleral alignment with little or no blanching of conjunctival vasculature, complete limbal clearance, and complete corneal clearance (Figs. 1 and 2). If the initial diagnostic lens did not completely clear the cornea, lenses with successively greater sagittal depth were applied until corneal clearance was realized. If the depth of the post-lens fluid reservoir was excessive, successively shallower lenses were applied until a more appropriate clearance was realized. Post-lens fluid reservoir depth between 0.15 and 0.4 mm was considered acceptable. Depth was estimated by comparing its thickness to corneal thickness. Once a lens with appropriate sagittal depth was identified, a spherocylindrical overrefraction was performed. All lenses were ordered either from Medlens Innovations or Essilor Contact Lens, Inc. Patients who decided to proceed with scleral lens fitting after initial evaluation received individualized instruction in the care and handling of their lenses. Each patient returned for evaluation of vision and lens fit several hours after completing the training. An additional follow-up visit was scheduled 2 to 4 weeks after 40
FIG. 2. Magnified view of scleral lens in situ. The scleral lens completely clears the cornea, reducing ocular surface discomfort, and the tear lens formed between the scleral lens and the cornea neutralizes much of the irregular astigmatism in keratoconus (black arrow indicates the anterior surface of the lens, white arrow indicates the posterior surface of the lens, and line segment indicates the depth of the post-lens fluid reservoir).
dispensing the lenses. Revised lenses were ordered as needed to achieve optimal vision, comfort, and fit. We assessed each patient’s ability to wear and handle the scleral lenses comfortably, visual acuity with scleral lens correction and with spectacle overrefraction compared with acuity with habitual correc-
FIG. 3. Distribution of monocular visual acuity with habitual refractive correction at the time of referral for scleral lens fitting (52 eyes of 32 patients with keratoconus), comparing patients who proceeded with scleral lens fitting to those who chose not to pursue scleral lens wear.
Eye & Contact Lens • Volume 36, Number 1, 2010
Eye & Contact Lens • Volume 36, Number 1, January 2010
Scleral Lenses in the Management of Keratoconus
TABLE 1. Characteristics of Patients Who Did Not Complete the Scleral Lens Fitting Process Patient
Age
Sex
1
28
F
2
63
F
3
71
F
Habitual correction
Reason for scleral lens evaluation
Eye
Spectacles
Contact lens intolerance
OS
Spectacles
Blurred vision
Corneal RGP
Contact lens intolerance
Entering visual acuity
Simulated keratometry
Reference sphere
Outcome; reason for outcome
20/60
52.12/47.62 @ 148
47.3
OD
20/40 ⫺ 2
Not available
40.3
OS
20/50 ⫹ 1
54.37/48.87 @ 122
48.6
OD
20/50 ⫺ 1
54.37/45.87 @ 086
50.8
OS
20/40 ⫺ 1
45.87/45.12 @ 034
45.2
Initial evaluation only; good spectaclecorrected VA OD (20/20) Initial evaluation only; no improvement in visual acuity due to lens opacity Initial evaluation only; handling concerns, no improvement in vision due to lens opacity Initial evaluation only; good uncorrected VA OD (20/20) and handling concerns Initial evaluation only; central corneal scar limited visual potential to 20/80, proceeded to transplant Initial evaluation only; lack of insurance coverage Initial evaluation only; minimal visual benefit demonstrated Initial evaluation only; minimal visual benefit demonstrated Initial evaluation only; good comfort and visual function with current correction Initial evaluation only; good uncorrected vision OS (20/20) Initial evaluation only; good spectaclecorrected vision, handling concerns Initial evaluation only; minimal visual benefit demonstrated Fit abandoned; had cataract surgery
4
17
M
No correction
Contact lens intolerance
OS
20/50
49.12/45/12 @ 034
47.5
5
18
M
Spectacles
Blurred vision
OD
20/400
Not available
56.0
6
26
M
Corneal RGP
Contact lens intolerance
OD
20/30 ⫺ 1
46.75/44.75 @ 034
44.8
OS
20/30 ⫺ 1
55.12/48/87 @ 148
48.7
OD
20/25 ⫺ 1
48.12/44.87 @ 056
45.3
OS
20/20
47.37/44.87 @ 120
45.0
OD
20/20
43.75/41.00 @ 002
41.6
OS
20/20
43.50/40.50 @ 180
41.2
OD
20/50 ⫹ 1
48.25/46.00 @ 002
46.5
7
8
9
28
33
33
M
M
M
Spectacles
Spectacles
Piggyback contact lenses
Contact lens intolerance; blurred vision Contact lens intolerance; blurred vision
10
37
M
No correction
Interest in scleral lenses (vision and comfort adequate in current correction) Interest in scleral lenses
11
42
M
Spectacles
Contact lens intolerance
12
13
49
66
M
F
Toric hydrogel lenses Spectacles
Contact lens intolerance; fluctuating vision Contact lens intolerance
OS
20/25 ⫺ 1
Not available
51.6
OD
2’/400
Not available
61.7
OD
20/25
48.00/46.12 @ 082
46.8
OS
20/20 ⫺ 1
47.87/46.62 @ 108
46.7
OD
20/30 ⫹ 1
45.37/39.75 @ 088
42.9
OS
20/20 ⫺ 1
44.37/36.87 @ 084
42.1
OD OS
20/40 10/400
47.86/46.62 @ 068 62.37/57.87 @ 108
46.6 53.5
RGP indicates rigid gas permeable; VA, visual acuity.
tion at the time of referral, the number of lenses ordered per eye, and the number of visits necessary to complete the fitting process.
RESULTS A total of 32 patients (52 eyes) were evaluated for scleral lens wear during the course of the study. At the time of presentation, 16 patients were primarily wearing spectacle correction, 8 were wearing corneal rigid gas-permeable lenses, 1 was wearing hydrogel toric lenses, 3 were wearing piggyback systems, and 4 were wearing no correction. Mean patient age was 39 years (range, 17–71 years) and 12 patients were women. Monocular visual acuity with habitual correction at the time of referral ranged from 20/20 to 20/400 (Fig. 3). Average follow-up was 22.5 months (range, 5–34 months). © 2010 Lippincott Williams & Wilkins
After initial consultation, 12 patients (20 eyes) chose not to proceed with the fitting process. The most common reason was a lack of visual benefit with scleral lenses compared with the habitual correction; 9 of the 12 patients were able to resolve 20/20 or 20/25 binocularly with their habitual correction. Patients 2, 3, and 5 (five eyes) had either lens or corneal opacities that precluded improvement in visual acuity with scleral lenses. One patient cited handling concerns as the determining factor in his decision not to pursue scleral lens wear. One patient (two eyes) had cataract surgery during the fitting process and found that her vision was adequate with spectacles after surgery. Characteristics of patients who were not successfully fit with scleral lenses are summarized in Table 1. Median entrance visual acuity of eyes considered for scleral lens wear in patients who chose not to pursue scleral lens fitting was 20/30. Median binocular acuity in these patients was 20/20. 41
M.M. Schornack and S.V. Patel
Eye & Contact Lens • Volume 36, Number 1, January 2010 TABLE 2. Summary of Fitting Process and Scleral Lens Design
Patient ID Age Sex 1
34
F
Habitual correction Piggyback contact lenses
2
43
F
Corneal RGP
3
44
F
Spectacles
4
44
F
Spectacles
5
46
F
Spectacles
6
47
F
Piggyback contact lenses Spectacles
7
8
52
61
F
F
9
20
M
10
22
M
11
23
M
12
27
M
13
30
M
Reason for scleral lens evaluation
Fluctuating vision, OD 48.12/46.25 dryness @ 144 OS 56.12/53.62 @ 088 Blurred and OD 49.37/44.50 fluctuating @ 076 vision Contact lens OD Not available intolerance; OS 54.37/48.12 blurred vision @ 146 Contact lens OS Not available intolerance; blurred vision Poor vision OD Not available
Corneal RGP
18
57
M
Spectacles
19
44
M
Corneal RGP
2
Standard Standard
20/80 20/25
45.7
54.00
2
3
Custom
20/400
44.3
65.92
1
3 4
Standard Unable to testb Standard 20/200
1
49.00
1
51.37
1
40.00
OS
49.8
Contact lens intolerance
M
1 1
52.25
Spectacles
39
52.25 48.12
2
M
17
57.7 47.7
43.25
31
Spectacles
20/40
2
15
M
Standard
42.12
Contact lens intolerance
Work-related RGP intolerance; blurred vision with spectacles Work-related RGP intolerance; blurred vision with spectacles Contact lens intolerance; fluctuating vision Contact lens intolerance; fluctuating vision
OD 61.87/51.12 @ 050 OS 52.00/46.37 @ 148
20/20
2
OD 45.00/41.87 43.4 @ 004 OS 45.50/43.50 43.6 @ 014 OD Not available Not available OS Not available Not available OS 66.5/48.12 54.8 @ 160 OD Not available 45.6
Corneal RGP
20/70
1
Blurred vision with spectacles and RGPs
M
20/60
46.00
2
OD 50.62/44.37 @ 046 OS 54.37/48.87 @ 144 OD Not available OS 44.87/41.00 @ 120 OD 46.87/44.87 @ 176 OS 47.25/47.25 @ 180 OD 53.00/45.37 @ 104 OS 62.12/50.12 @ 164 OD 49.25/42.87 @ 038 OS 48.75/45.25 @ 132 OD 54.50/49.25 @ 060
Standard
46.6
2
OS
20/40
2
50.50
49.25/48.25 @ 044 Not available
20/30
51.87
52.25
Contact lens No correction intolerance Spectacles Contact lens intolerance Corneal Contact lens RGP intolerance Corneal Recurrent apical RGP erosions; contact lens intolerance Spectacles Contact lens intolerance
Standard
48.4
50.9
No Contact lens correction intolerance; blurred vision
Entrance
With scleral (plus spectacle overrefraction)
1
46.9
Not available
Lens design
48.12
OS
3
Visual acuity
44.8
OD Not available
31
39
Reference sphere
Contact lens intolerance
14
16
Eye
Simulated keratometry
Base curve of final No. No. lens lenses visits
20/30 (20/20) 20/25 (20/20) 20/400a (20/20) 20/40 (Lea symbols) 20/40
Standard
20/25
Standard
20/50
20/40 (20/20)
Standard
20/30
20/25 (20/20)
Custom
20/200
20/70
Custom
20/60
20/25 ⫺ 2
3
Custom
20/400
20/60 ⫹ 2
2
3
Standard
20/50
20/25 ⫺ 1
46.00
1
2
Standard
20/50
20/20
55.7
50.50
1
3
Standard
20/30
20/30
44.9
45.12
1
3
Standard
20/25
20/20
47.8
48.12
1
Standard
20/50
20/20
48.2 43.2
46.87 46.87
2 2
3
Standard Standard
20/40 20/20
20/20 20/20
45.3
46.87
1
2
Standard
20/20
20/20
47.0
48.12
1
Standard
20/20
20/20
50.8
48.12
2
Standard
20/50
20/20
56.1
61.00
3
Custom
20/150
20/70
46.2
49.87
1
Standard
20/20
20/20
46.6
49.12
1
Standard
20/20
20/25
48.2
49.00
1
2
Standard
20/30
57.7
49.00
2
3
Custom
20/50
20/40
49.2
43.50
2
Custom
20/40
20/30
3
3
4
3
20/25
20/25 (20/20)
a Unilateral scleral lens fit, high myopia in the right eye, intentional undercorrection in the scleral lens reduced the risk of spectacle-induced aniseikonia. b
Down syndrome, unable to measure visual acuity with Snellen chart, Lea chart not available at initial examination.
RGP indicates rigid gas permeable.
42
Eye & Contact Lens • Volume 36, Number 1, 2010
Eye & Contact Lens • Volume 36, Number 1, January 2010
FIG. 4. Comparison of visual acuity with habitual correction at the time of presentation to visual acuity with scleral lenses in patients who were successfully fit.
The remaining 19 patients (30 eyes) were successfully fit with Jupiter scleral lenses. Demographic characteristics, information on habitual refractive correction at the time of referral, topographic indices, and a summary of the fitting process for these patients are summarized in Table 2. Acceptable scleral lens fit was achieved in an average of 2.8 visits (range, 2– 4 visits). Fitting was completed in 2 visits for 5 patients, in 3 visits for 12 patients, and in 4 visits for 2 patients. On average, 1.5 lenses (range, 1–3) were ordered for each eye during the fitting process. The first lens ordered was the lens prescribed for 17 eyes (57%), the second lens ordered was the lens prescribed for 12 eyes (40%), and the third lens ordered was the lens prescribed for 1 eye. Standard lens designs were prescribed for 23 eyes (77%) whereas 7 eyes required custom designs to optimize the scleral lens fit. Median monocular entrance visual acuity of eyes of patients who were successfully fit with scleral lenses was 20/40. Median binocular acuity at initial examination was 20/25. After scleral lens fitting, visual acuity improved by an average of 2.9 lines, and median visual acuity was 20/20 (Fig. 4).
DISCUSSION Awareness of the potential benefits of large-diameter rigid gas-permeable lenses for patients with a wide range of ocular conditions has been steadily increasing during the past several years. Management of corneal ectasia with scleral contact lenses has been described in several studies.11,12,15,17,18 Pullum and Buckley17 reported a 60% overall success rate in a group of 530 patients fit with scleral lenses for a variety of diagnoses, more than half of which had keratoconus. Segal et al.18 fitted 48 patients (66 eyes), of whom 75% had keratoconus, with an overall success rate of 90%. Visser et al.19 described the use of the ProCornea lens and reported that 50% of patients fitted with that particular scleral design had keratoconus. As noted earlier, 15% of patients referred to us for scleral lens evaluation had keratoconus. We successfully fitted 59% of all patients with keratoconus referred to us for scleral lens evaluation. All but one of our patients who ultimately chose not to pursue scleral lens wear decided to continue with their habitual correction immediately after initial scleral lens evaluation; the majority (9 of 12, 75%) of these patients were able to resolve 20/25 (Snellen) or better binocularly with their habitual correction. We were able to provide acceptable vision and comfort with scleral lenses in 95% (19 of 20) patients who chose to proceed with the fitting process after initial evaluation. Corneal rigid gas-permeable lenses have long been assumed to provide the best possible visual acuity in patients with keratoco© 2010 Lippincott Williams & Wilkins
Scleral Lenses in the Management of Keratoconus nus. In severe keratoconus, the irregularity of the anterior corneal surface can make it difficult to achieve reasonable lens centration and stability with corneal lenses. A retrospective study by Salam et al.20 indicated that scleral contact lenses provide visual acuity that was comparable with that attained with corneal lenses in patients with moderate to severe keratoconus. Significant improvement in visual acuity was reported with scleral lenses in patients with keratoconus in the study by Visser et al.,21 and Segal et al.18 reported that 91% of patients with keratoconus achieved 20/40 or better acuity with scleral lenses. Similarly, 87% of our patients achieved 20/40 or better Snellen acuity with scleral lenses. The perception that fitting large-diameter lenses is time consuming, costly, and complex may be limiting their widespread use at present. Our experience suggests that fitting scleral lenses with the use of standard diagnostic trial sets may be similar to, or even easier than, fitting corneal or corneoscleral rigid lenses. Although keratoconus can cause considerable corneal irregularity, our ability to successfully fit scleral lenses with regular peripheral parameters suggests that the contour of scleral tissue may be less affected by the disease. Fitting scleral lenses avoids the challenges associated with attempting to balance lenses on highly irregular tissue and to instead align the lenses with relatively normal scleral tissue. Advanced imaging technology can certainly be used to design scleral lenses,22 but we were able to successfully fit Jupiter lenses by standard diagnostic lenses. We habitually collect topographic data on patients with keratoconus before any contact lens fitting; therefore, we did obtain topography on patients in this study. However, we did not observe a close association between any single topographic index and the base curve of the final scleral lens prescribed. It is likely that we could have successfully fit Jupiter scleral lenses with diagnostic lenses in the absence of any topographic data. Diagnostic lens fitting carries the added advantage of allowing the patient to experience the sensation and vision that can be expected with scleral lenses before committing to the complete fitting process. The majority (77%) of the lenses that we prescribed were standard designs, although we used consultative services provided by the lens manufacturers to assist us in designing custom lenses when necessary. Base curve radius and diameter can be adjusted, as can radius of curvature and diameter of any of the four peripheral curves, to create appropriate sagittal depth across the entire cornea and limbus. The wide variety of corneal lens options (rigid gas-permeable lenses, hybrid lenses, custom hydrogels, and piggyback systems) allow for adequate management of most cases of keratoconus, and these options may certainly be explored before considering scleral lenses. However, some patients with keratoconus do not achieve adequate vision or comfort with corneal contact lenses. Furthermore, one patient in our series experienced recurrent apical erosions with corneal lenses. In situations such as this, scleral lenses may be advantageous because they vault the cornea and allow the entire corneal epithelium to be bathed with fluid. Scleral lenses can be used to manage ocular surface diseases such as neurotrophic keratitis12 or graft versus host disease.23 The stability of scleral lenses along with their generous optical zone diameter (8.2– 8.6 mm) allow them to provide consistent vision; lens awareness is minimized because the conjunctival tissue on which scleral lenses rest is less sensitive compared with corneal tissue, and lid interaction is minimized because the lenses extend well into the fornices. The Collaborative Longitudinal Evaluation of Keratoco43
M.M. Schornack and S.V. Patel nus study found that contact lens wear was associated with an increased risk of corneal scarring in patients with keratoconus (odds ratio, 2.50).6 Because scleral lenses do not touch the cornea, the risk of apical scarring could potentially be less with scleral lenses than with traditional corneal lenses. This intriguing possibility has not been formally studied but may warrant further investigation. Corneal contact lens intolerance is one of the primary indications for keratoplasty in patients with keratoconus.24 The option of fitting scleral lenses may defer the need for keratoplasty in patients who are intolerant to traditional contact lens designs and who do not have visually significant corneal scarring. Although penetrating keratoplasty has a 93% to 96% initial success rate,24 many patients still require rigid contact lenses for their best vision, and complications can occur including graft rejection and graft failure in approximately 20% and 10% of eyes, respectively, over 15 years.25 Furthermore, ectasia can recur in 6% to 11% of eyes receiving a penetrating keratoplasty for keratoconus,26,27 frequently requiring repeat keratoplasty in this young group of patients.28 Scleral lenses can provide good vision and comfort in many contact lens-intolerant patients and may delay the need for primary or repeat surgical intervention in this relatively young group of patients. At present, there is considerable confusion regarding the terminology used to describe large-diameter lenses. We have suggested that lenses be described based on their fitting characteristics rather than their overall diameter. Lenses that do not extend beyond the limbus are generally considered to be “corneal” lenses. Lenses that extend past the limbus but rest on the cornea could be referred to as “corneoscleral” lenses. Lenses that are supported entirely by the sclera, completely clear the limbus, and measurably vault the cornea could be defined as “scleral” lenses.23 By these definitions, the lenses described in this study would be defined as scleral lenses.
CONCLUSIONS Scleral lenses can provide good vision and comfort for patients with keratoconus. Our early experience with the Jupiter lenses suggests that a diagnostic fitting process is reasonably efficient. The lenses may delay the need for keratoplasty in patients who have exhausted other options for visual correction. Therefore, we consider Jupiter scleral lenses an excellent option for patients with keratoconus who achieve inadequate outcomes with spectacles or corneal contact lenses. ACKNOWLEDGMENTS The authors thank Dr. Keith Baratz for his assistance in the preparation of this manuscript. REFERENCES 1. Krachmer JH, Feder RS, Belin MW. Keratoconus and related noninflammatory corneal thinning disorders. Surv Ophthalmol 1984;28:293–322.
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Eye & Contact Lens • Volume 36, Number 1, January 2010 2. Negishi K, Kumanomido T, Utsumi Y, et al. Effect of higher-order aberrations on visual function in keratoconic eyes with a rigid gas permeable contact lens. Am J Ophthalmol 2007;144:924 –929. 3. Kennedy RH, Bourne WM, Dyer JA. A 48-year clinical and epidemiologic study of keratoconus. Am J Ophthalmol 1986;101:267–273. 4. Zadnik K, Barr JT, Edrington TB, et al. Baseline findings in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. Invest Ophthalmol Vis Sci 1998;39:2537–2546. 5. Barr JT, Schechtman KB, Fink BA, et al. Corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study: Baseline prevalence and repeatability of detection. Cornea 1999;18:34 – 46. 6. Barr JT, Wilson BS, Gordon MO, et al. Estimation of the incidence and factors predictive of corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. Cornea 2006;25:16 –25. 7. Barr JT, Zadnik K, Wilson BS, et al. Factors associated with corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. Cornea 2000;19:501–507. 8. Pearson RM. Kalt, keratoconus, and the contact lens. Optom Vis Sci 1989;66:643– 646. 9. Pearson RM, Efron N. Hundredth anniversary of August Muller’s inaugural dissertation on contact lenses. Surv Ophthalmol 1989;34:133–141. 10. Efron N, Pearson RM. Centenary celebration of Fick’s Eine Contactbrille. Arch Ophthalmol 1988;106:1370 –1377. 11. Schein OD, Rosenthal P, Ducharme C. A gas-permeable scleral contact lens for visual rehabilitation. Am J Ophthalmol 1990;109:318 –322. 12. 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;31:130 –134. 13. Pullum KW, Whiting MA, Buckley RJ. Scleral contact lenses: The expanding role. Cornea 2005;24:269 –277. 14. Cotter JM, Rosenthal P. Scleral contact lenses. J Am Optom Assoc 1998; 69:33– 40. 15. Pullum KW. The unique role of scleral lenses in contact lens practice. Cont Lens Anterior Eye 1999;22(suppl 1):S26 –S34. 16. Tan DT, Pullum KW, Buckley RJ. Medical applications of scleral contact lenses. I. A retrospective analysis of 343 cases. Cornea 1995;14:121–129. 17. Pullum KW, Buckley RJ. A study of 530 patients referred for rigid gas permeable scleral contact lens assessment. Cornea 1997;16:612– 622. 18. Segal O, Barkana Y, Hourovitz D, et al. Scleral contact lenses may help where other modalities fail. Cornea 2003;22:308 –310. 19. Visser ES, Visser R, van Lier HJ, et al. Modern scleral lenses. I. Clinical features. Eye Contact Lens 2007;33:13–20. 20. Salam A, Melia B, Singh AJ. Scleral contact lenses are not optically inferior to corneal lenses. Br J Ophthalmol 2005;89:1662–1663. 21. Visser ES, Visser R, van Lier HJ, et al. Modern scleral lenses. II. Patient satisfaction. Eye Contact Lens 2007;33:21–25. 22. Gemoules G. A novel method of fitting scleral lenses using high resolution optical coherence tomography. Eye Contact Lens 2008;34:80 – 83. 23. Schornack MM, Baratz KH, Patel SV, et al. Jupiter scleral lenses in the management of chronic graft versus host disease. Eye Contact Lens 2008; 34:302–305. 24. Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998;42:297–319. 25. Patel SV, Hodge DO, Bourne WM. Corneal endothelium and postoperative outcomes 15 years after penetrating keratoplasty. Trans Am Ophthalmol Soc 2004;102:57– 65; discussion 65– 66. 26. Pramanik S, Musch DC, Sutphin JE, et al. Extended long-term outcomes of penetrating keratoplasty for keratoconus. Ophthalmology 2006;113:1633– 1638. 27. Raecker ME, Erie JC, Patel SV, et al. Long-term keratometric changes after penetrating keratoplasty for keratoconus and Fuchs endothelial dystrophy. Am J Ophthalmol 2009;147:227–233. 28. Patel SV, Malta JB, Banitt MR, et al. Recurrent ectasia in corneal grafts and outcomes of repeat keratoplasty for keratoconus. Br J Ophthalmol 2009; 93:191–197.
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