Scleral and Mini-Scleral Lenses: A Case Series
SCLERAL LENS CASES
Scleral and Mini-Scleral Lenses: A Case Series
When no other vision correction options work, scleral lenses can change patients' lives.
By Jack Hartstein, OD, MD; Michael A. Ward, MMSc, FAAO; Michael J. Lipson, OD; & Christopher A. Gilmartin, OD
|Dr Hartstein is the author of several books on contact lenses and is a consultant in the contact lens clinic of Washington University School of Medicine, St. Louis, Mo.|
Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and Director, Emory Contact Lens Service. You can reach him at email@example.com.
Dr. Lipson is an assistant professor at University of Michigan, Department of Ophthalmology and Visual Sciences. He has a specialty contact lens practice in Livonia, Mich. He presents nationally and internationally on specialty lens fitting and corneal reshaping.
Dr. Gilmartin is a part-time assistant clinical faculty member in the Department of Cornea and Contact Lenses at the University of Missouri-St Louis College of Optometry. He spends the balance of his time in a specialty private practice setting.
A new trend in irregular cornea contact lens fitting has emerged in recent years. Scleral (>18mm in diameter) and mini-scleral (15mm to 18mm) lenses offer numerous advantages over corneal lenses in addressing the needs of irregular cornea patients, including those who have a history of penetrating keratoplasty, dry eye, keratoconus, and various corneal dystrophies. In addition to the optical advantages of a vaulted corneal fit, the large diameter of scleral and mini-scleral lenses allows for much better centration, improved comfort, and extremely low likelihood of lens ejection. They are now frequently selected as the method of choice for correcting vision in patients who have a wide range of corneal disorders. This case series shows how these designs can greatly improve the quality of patients' lives.
CASE #1: Salzmann's Nodular Degeneration (Jack Hartstein, OD, MD)
Background A 59-year-old white female developed an intolerance to soft contact lenses, which she had worn for many years. Her vision had decreased to the level of 20/100 in each eye. She was wearing Focus Toric (Ciba Vision) monthly replacement lenses in each eye (monovision) with the following parameters: OD −4.25 −1.75 x 020 and OS −2.25 −1.75 x 100; 8.9mm base curve; 14.5mm overall diameter (OAD).
She also had a history of dry eye syndrome but no ocular confirmation.
Test Procedures, Fitting, Design, and Ordering The patient's manifest refraction was OD −7.00 +2.00 x 125 20/20− and OS −7.00 +1.75 x 025 20/25. The add was 2.50D OD and OS.
Slit Lamp Examination The right and left corneas exhibited superior nodular elevation consistent with Salzmann's Nodular Degeneration. Epithelial erosion was noted over the largest nodule, which centered in the right cornea and stained with fluorescein.
Lens Design/Fitting As the patient could no longer obtain useful vision with soft contact lenses and she had been a long-time contact lens wearer, we initially fit her into GP lenses ranging in diameter from 9.0mm to 9.5mm. She found them intolerable.
We then fit her with the following MSD (Blanchard) mini-scleral design contact lenses in a monovision (OD distance, OS near) modality:
• OD: OAD 15.8mm, Sag 3.8, Power −1.50D
• OS: OAD 15.8mm, Sag 3.8, Power −4.00D
Evaluation with fluorescein demonstrated good peripheral alignment and mild central clearance. Her vision corrected to 20/20 in her right eye and 20/20 at near in the left eye.
At the one-week and three-month follow-up visits, the patient was quite satisfied with her lenses. Slit lamp findings were similar to those at the fitting visit. She was symptom-free and found the lenses completely comfortable.
Discussion It is evident that mini-scleral lenses have an excellent application in cases of corneal degeneration, such as with this patient. She is extremely satisfied with these lenses; however, we explained to her that should she develop a progressive visual decline that is not correctable with these lenses, she may benefit from removal of the Salzmann's Nodule by a superficial keratectomy combined with phototherapeutic keratectomy with the excimer laser and the use of a topical mitomycin-C. Fortunately, this is a remote possibility as a result of the subjective and objective performance of these contact lenses.
Figure 1. Granular corneal dystrophy viewed with white light.
Figure 2. Granular corneal dystrophy viewed under retroillumination with fundus background.
CASE TWO: Granular Dystrophy (Michael A. Ward, MMSc, FAAO)
Background Granular corneal dystrophy (GCD) is an autosomal dominant, bilateral condition that results in deposition of white granular opacities in the cornea that progress throughout adulthood. It tends to develop in the central corneal stroma and eventually can cause decreased vision and eye discomfort. Patients who have granular dystrophy may have decreased vision, photosensitivity, and/or eye pain from recurrent corneal erosions. It may complicate contact lens wear or make it unbearable. However, GP contact lenses provide the best quality of vision correction in these individuals.
This 51-year-old patient was diagnosed with GCD at age 22. She underwent excimer phototherapeutic keratectomy (PTK) in 1991, OD only. Her manifest refraction changed from −1.75 +1.75 x 090 (20/40 +4) to +9.75 +1.25 x 100 (20/40) six months after surgery. Nevertheless, she was successfully fit into a soft daily wear lens that she currently wears today for near vision.
Her left unoperated eye had the following manifest refraction (1991): OS −1.75 +2.25 x 113 (20/30). However, her challenges pertained to the left eye as a result of the anisometropia, a very irregular cornea, and episodic epithelial breakdown and erosions resulting from the dystrophy. She had a history of failure with numerous contact lens modalities including a spherical lens, soft toric lens, spherical standard diameter GP, and a piggyback combination. She achieved satisfactory visual acuity with both the spherical GP and the piggyback combination lenses, but the comfort was unacceptable. Her quality of life became more challenged when, in late 2007, her husband passed away and she was unable to drive as a result of reduced vision. She was told that surgery was not an option for this eye.
Test Procedures, Fitting, Design, and Ordering The patient returned to Emory University in February 2008 for re-evaluation. Her bestcorrected visual acuity was 20/200 in the left eye.
Slit Lamp Examination Figures 1 (white light), and 2 (retroillumination with fundus background) show her granular dystrophy, which was, in fact, resulting in very compromised vision.
Corneal Topography Her keratometry values were 41.7/49.2 @ 118 (moderate mire irregularity). Figure 3 shows her corneal topography map. Her simulated K values were 43.34 @ 010; 48.49 @ 100.
Figure 3. Corneal topography map of granular corneal dystrophy patient.
Lens Design In February 2008, we fitted her into a mini-scleral lens with the following parameters:
• OAD: 15.8mm
• Base curve radius (BCR): 7.34mm
• Peripheral curve radii/widths: 7.54/1.7mm, 8.70/0.9mm, 12.75/0.5mm, 14.25/0.47mm.
This lens exhibited good centration (Figure 4) and adequate central clearance with fluorescein. The patient has been ecstatically happy with this lens since the time of dispensing. She achieved a visual acuity equal to 20/40 and was able to pass her driver's license vision examination.
Figure 4. Centered mini-scleral lens on granular corneal dystrophy patient.
Discussion This case is an excellent example of how scleral contact lenses can change an individual's life. Because of the resulting corneal irregularity, other contact lens options resulted in either poor vision or unacceptable lens awareness.
CASE THREE: Scleral Lenses for Severe Dry Eyes (Michael J. Lipson, OD, FAAO)
Background The majority of individuals who receive allogeneic (from matched donors) stem cell transplants experience a severe immune response called Graft-versus-Host Disease (GVHD). GVHD manifests as a variety of changes throughout the body. These include skin eruptions/rash, abnormal liver function, gastro-intestinal disturbances, renal disease, and dysfunction of any of the mucous tissues of the body (oral, sinus, vaginal, and ocular). The ocular manifestations are quite severe and extremely uncomfortable. These include fibrosing and inflammation of the lacrimal glands, reduction of tear quantity, punctate keratitis, papillary conjunctivitis, corneal abrasion, corneal ulcer, and corneal edema. These changes result in symptoms that include severely dry eyes, photophobia, scratchy eyes, blurred vision, red eyes, eyelid redness, and lid inflammation.
Treatment for the ocular symptoms has included frequent use of lubricants in the form of drops, liquid gels, or ointments that many patients require every 20 to 30 minutes. In addition, anti-inflammatory steroid drops such as loteprednol or prednisone as well as cyclosporine drops (Restasis, Allergan) are frequently prescribed. Even with the various regimens of eye drops mentioned above, most patients still report severe discomfort, redness, light sensitivity, and blurred vision.
Good experiences with scleral lenses in other challenging cases has led practitioners to fit scleral lenses on GVHD patients as well as on patients who have severe dry eyes and corneal epithelial pathologies caused by exposure and/or dryness. Scleral lenses can provide relief for these pathologies because they retain a reservoir of tears under the lens and over the corneal surface. Practitioners working with these lenses have reported improved comfort for dry eye patients as well as success in alleviating symptoms for GVHD patients, improving the quality of life for these very uncomfortable individuals.
Our patient was a 52-year-old Caucasian male computer programmer who presented for evaluation for scleral lenses after being referred by a corneal specialist. He'd had a bone marrow transplant from a matched, unrelated donor one-and-one-half years previously for non-Hodgkins Lymphoma. He reported progressively increasing eye discomfort, foreign body sensation, light sensitivity, and blurred vision over the last year. He also reported increasing severity of symptoms as the day progresses. His symptoms made it difficult for him to work at the computer and virtually impossible to be outdoors.
He was taking numerous systemic medications. One month prior he had Smart Plug (Medennium) punctal plugs inserted into the lower puncta of each eye. His regimen of eye drops included Restasis b.i.d., Refresh Tears (Allergan) q30 minutes all day, and Refresh Lacrilube (Allergan) at bedtime and also in the evening about two to three hours before bedtime. He occasionally used Systane (Alcon) and Theratears Liquid Gel (Advanced Vision Research). He was also taking Theratears oral supplements.
Test Procedures, Fitting, Design, and Ordering The patient's visual acuity at the initial examination with his current glasses was OD 20/30 and OS 20/200 (at 2:05 pm). At the previous exam with the corneal specialist, his VA was OD 20/25 and OS 20/70 at 9:30 am.
Slit Lamp Examination The right eye had 1+ scattered superficial punctate keratitis (SPK) throughout the cornea, and the left eye showed 3 to 4+ SPK across the whole cornea (Figure 5) in addition to numerous filamentary formations on the central cornea. He also showed 2+ meibomian gland dysfunction with 2 to 3+ lid margin hyperemia. The palpebral conjunctiva was hyperemic (2 to 3+) with a very rough appearance.
Figure 5. Severe staining resulting from dry eye in patient who has Graft-versus-Host Disease.
Corneal Topography Topography and keratometry showed slight distortion (D) in the right eye and severe distortion in the left eye. Keratometry OD was 43.25 x 44.62 (D Grade 1) and OS 42.12 x 43.75 (D Grade 3 to 4). Manifest refraction (unchanged from his current glasses) was OD −1.50 −0.25 x 167 20/30 and OS −0.75 −1.00 x 067 20/200. Schirmer's tear test results were OD 4mm and OS 0mm.
Lens Fitting We proceeded with diagnostic fitting of scleral lenses. His corneal diameter was 11.5mm. I usually start with an 18.2mm OAD and select a base curve radius that is 1.00D steeper than the steepest K reading to assure adequate corneal vaulting.
The diagnostic lenses selected had the following parameters:
• OD: 18.2mm OAD, 7.5mm BCR, −5.00D
• OS: 18.2mm OAD, 7.67mm BCR, −4.00D
Slit lamp examination showed significantly large bubbles under both lenses, indicating excessive vaulting. Flattening the BCR by 1.00D for both lenses resulted in very small bubbles that may have resulted from application difficulties. Edge lift was very slight—which is desirable with these lenses—and peripheral bearing was moderate without excessive vascular impingement.
The lenses ordered had the following parameters:
• OD: OAD/optical zone diameter (OZD) 18.2mm/8.2mm, BCR 7.67mm, −2.00D BVP
• OS: OAD/OZD 18.2mm/8.2mm, BCR 7.85mm, −0.75 BVP
Our patient reacted very well to the lenses both physically and visually. As with most patients who wear scleral lenses for the first time, he said they were more comfortable than he expected. During the diagnostic fitting, after having lenses on for about 45 minutes, he reported that his eyes felt better than they had for quite some time. We discussed adaptation and lens care in addition to the learning curve for application and removal. He was very excited about this new treatment for something that was very uncomfortable, making his daily life difficult, and that his regimen at the time was not adequately treating.
After lens dispensing and instruction, the patient returned for followup care after one week of wear. He reported very easy adaptation to wearing the lenses, which he had gradually increased to 10 hours per day of wear. He reported struggling with removal at times, but that he was able to apply the lenses quite easily. He also noted that he only needed to use lubricating eye drops twice during the 10 hours of wear. He was evaluated again at one month, at which time he reported wearing the lenses 14 to 16 hours per day, using lubricating eye drops two to three times during the day, and that his eyes still felt better after he removed the lenses.
Slit lamp evaluation revealed an absence of superficial punctate staining with only a trace amount of conjunctival hyperemia (significantly reduced from pre-fitting levels). The lenses were clean, centered perfectly, and showed central corneal clearance with no bubbles and peripheral bearing without conjunctival vessel impingement or scleral impression (Figure 6).
Figure 6. Fluorescein pattern of scleral lens on Graft-versus-Host Disease patient.
Most significantly, the patient reported that since he began wearing scleral contact lenses his life had improved significantly. First, his eyes were much more comfortable throughout the day. Second, his light sensitivity was much less so that he could walk outside in comfort (with sunglasses). Third, he could see well and work comfortably at his computer for periods of time that allowed him to be productive. Finally, he said that just being able to keep his eyes open made socializing possible. Overall, he was thrilled with the improvements the scleral lenses have made. He is comfortable with the process of application and removal.
We will continue to see the patient for follow up every four months to assure continued corneal and conjunctival health as well as clean lenses with good wetting qualities. He may require additional followup care if there are changes in his disease process or treatments.
Discussion Scleral contact lenses provide a viable treatment for the extremely dry eyes in patients who have GVHD that is not well-addressed with traditional treatments such as eye drops. This segment of patients is being successfully treated with specially designed, highly permeable scleral lenses. Unfortunately, few eyecare practitioners are trained and experienced in fitting scleral lenses. Demand for these lenses will increase in years to come as more allogeneic HSCTs are performed.
There is a definite learning curve in fitting scleral contact lenses, but the improved quality of life and significant relief of symptoms achieved by these severe dry eye/GVHD patients is well worth the effort on our part. Other than the lubricating eye drops, anti-inflammatory eye drops, punctal plugs, or systemic anti-inflammatory medications described above, there are no other alternative treatments to scleral contact lenses for severe dry eyes in GVHD. In fact, at this time, scleral contact lens fitting appears positioned as the treatment alternative of last resort. The treatment goal for these severely dry eyed patients is to maintain a healthy, smooth, and hydrated corneal surface. Scleral GP contact lenses address all of these issues.
CASE FOUR: Scleral Contact Lenses for Post-Penetrating Keratoplasty (Christopher A. Gilmartin, OD)
Background Penetrating keratoplasty (PK) can be therapeutic for a variety of corneal conditions including keratoconus, Fuchs' endothelial dystrophy, traumatic scarring, and others. But even in the hands of the most experienced corneal surgeon, there is often resultant irregular corneal astigmatism. In these cases, GP lenses will usually provide the best visual outcome. While many post-PK corneas are fitted with corneal GP contact lenses, the dramatic irregularity of these corneas can present a serious challenge to even the most experienced fitters. Common complaints from post-PK patients fitted with corneal GP contact lenses are frequent lens ejection, poor comfort, and unstable vision.
A 59-year-old Caucasian male factory supervisor presented for a mini-scleral contact lens fitting of his left eye after referral by his primary care optometrist. Significant medical history included benign prostatic hypertrophy and systemic hypertension. Relevant ocular history included bilateral penetrating keratoplasty at age 38 OD and at age 45 OS. He underwent extra-capsular cataract extraction with intraocular lens implantation OD and OS in early 2001 and subsequent YAG capsulotomy OD and OS in 2002. The left eye had been previously fit in numerous corneal GPs without complete success. The patient's chief complaint was frequent lens ejection. He also complained of poor vision and comfort through all of the previously attempted lenses, which included several spherical GPs and, most recently, a front-surface toric design. In his spare time, he enjoyed wild game hunting, but had been unable to do this for years due to frequent lens ejections and unstable vision.
Test Procedures, Fitting, Design, and Ordering Entering visual acuities (VA) were 20/20 OD through his habitual spherical GP contact lens and 20/50 OS (PH 20/25) through his habitual front-surface toric GP lens. The patient reported that he had been unable to wear spectacles for distance vision correction since he was in his early thirties. Orbscan (Bausch + Lomb) corneal topography evaluation revealed irregularity of ± 5.1D in the 3mm zone and ± 8.6D in the 5mm zone.
The patient's small interpalpebral fissure width influenced the overall diameter of the initial diagnostic lens. Given the irregularity of the graft, a larger diameter mini-scleral in the 18.0mm range was preferred; however, we chose the standard Jupiter (Essilor) 15.6mm fitting set because it would be more practical given the patient's level of dexterity and potential difficulties with application and removal.
Diagnostic Lens #1:
• Jupiter (standard geometry)
• OAD: 15.6mm
• OZD: 8.6mm
• Power: −8.00D
• BCR: 7.03mm (corneal chamber)
• Peripheral Curve 1 (PC1): 7.23mm for 1.7mm (corneal chamber)
• PC2: 8.7mm for 0.9mm (corneal chamber)
• PC3: 12.75mm for 0.5mm (scleral curve)
• PC4: 14.25mm for 0.4mm (scleral curve)
Slit Lamp Evaluation Immediately after application, there was approximately 40 microns of central clearance with circumferential bearing in the midperipheral cornea. The patient reported "double vision" and marginal comfort. Because of the poor fitting relationship, we did not perform an over-refraction (OR) or allow the lens to settle. The midperipheral bearing in the presence of low central clearance warranted a steeper BCR selection. If the areas of bearing can be vaulted without excessively vaulting the central cornea, a reverse geometry design would be unnecessary.
Diagnostic Lens #2:
• Jupiter (standard geometry)
• OAD/OZD: 15.6mm/8.6mm
• Power: −11.00D
• BCR: 6.62mm
• PC1: 6.82mm for 1.7mm
• PC2: 8.7mm for 0.9mm
• PC3: 12.75mm for 0.5mm
• PC4: 14.25mm for 0.4mm
Slit Lamp Evaluation After an hour of settling, central clearance was approximately 100 microns. The graft was completely vaulted. Minimum clearance over the graft was at the interface and was approximately 80 microns. The corneal chamber was too small, indicated by the lens landing on the cornea just inside the limbus nasally and temporally. There was significant blanching of the conjunctival vessels at the third and fourth peripheral curves around most of the lens, indicating tightness at the scleral curves. Over-keratometry revealed 0.50D of with-the-rule lens flexure.
With the lenses in situ, VA was 20/100. Through a spherical OR of +2.50D, VA was 20/40−. Through a sphero-cylindrical OR of +3.25 −2.00 x 154, VA improved to 20/20.
Lens Order #1:
We left the base curve of the second diagnostic lens unchanged. The sphero-cylindrical OR was added to the trial lens power to obtain the final power. The corneal chamber was too small in the trial fit,
so we increased the OZD from 8.6mm to 9.0mm to enlarge it. Increasing corneal chamber diameter without compensatory flattening of the BCR results in greater clearance over the cornea, which was desirable because there was minimal clearance of 80 microns over the graft interface in a small area. There was blanching at the scleral curves, so we flattened these to improve the peripheral fit:
• OAD/OZD: 16.0mm/9.0mm
• Power: −7.75 −2.00 x 154 (prism-ballasted frontsurface toric)
• BCR: 6.62mm
• PC1: 6.82mm for 1.7mm
• PC2: 8.7mm for 0.90mm
• PC3: 13.00mm for 0.50mm
• PC4: 14.5mm for 0.40mm
Two weeks after the initial fit, the patient returned for the first dispense. The lens was applied and allowed to settle for an hour.
Slit Lamp Evaluation After settling, central clearance was approximately 250 microns. Enlarging the corneal chamber had achieved full limbal clearance. Minimum clearance over the graft was approximately 175 microns. The scleral curves still showed some mild vessel blanching around most of the lens periphery. The lens was rotated 10 degrees nasally and was stable.
In situ, VA was 20/20. The patient reported good comfort. Through a sphero-cylindrical OR of plano −0.50 x 180, VA was 20/20+. We did not dispense the lens because of the tight peripheral fit.
Lens Order #2:
• OAD/OZD: 16.0mm/9.0mm
• Power: −7.75 −2.00 x 154 (prism-ballasted frontsurface toric)
• BCR: 6.62mm
• PC1: 6.82mm for 1.7mm
• PC2: 8.7mm for 0.90mm
• PC3: 13.50mm for 0.50mm
• PC4: 15.0mm for 0.40mm
Two weeks later, the patient returned for the second dispense. The only changes made to the initial order were to flatten the third and fourth peripheral curves in order to loosen the scleral fit and allow for optimal tear exchange. After settling, the central fit was unchanged compared to the initial ordered lens, but the scleral fit now showed good alignment. This was evident by the absence of conjunctival vessel blanching, positive tear exchange, and relative ease of removal after settling. The lens position, OR, and visual acuity was unchanged compared to the previous visit.
The patient returned for a training visit. After working on specifics of his technique (i.e. finger placement, where to direct his gaze, eyelid position, etc), he was able to demonstrate competency with application and removal, so we dispensed the lens for daily wear. We prescribed Unisol 4 (Alcon ) as filling media and Boston Simplus (B+L) for cleaning and disinfection. Refresh Optive Sensitive (Allergan) was prescribed for rewetting over the lens.
Follow-Up Visit After one week, the patient returned for follow up having worn the lens for several hours. He reported excellent vision and comfort, but said he was still struggling with application, often taking several attempts before applying the lens successfully. He reported no difficulty with removal. In situ, VA was 20/20 OS. Perhaps most importantly, the patient reported no lens ejections.
Slit Lamp Evaluation The lens was rotated 10 degrees nasally and was stable. Fluorescein was applied over the lens and allowed to exchange with the fluid in the tear chamber. The central and peripheral fits were still acceptable, showing full clearance over the cornea and alignment to the sclera, respectively. The minimum clearance over the graft was approximately 125 microns. The lens was removed to inspect the cornea. The epithelium showed no defects and the graft was clear.
We finalized the prescription on this visit; however, the patient wished to be fitted in his right eye and returned the following week to begin the process. He continues to wear the left lens with excellent vision and comfort.
Discussion One of the primary advantages of a mini-scleral lens for this patient is the potential to mask the substantial irregular corneal astigmatism. If internal astigmatism is minimal and the lens is not flexing on the eye, the predicted OR should be close to spherical even in the presence of significant corneal irregularity. In this case, however, a spherical OR did not yield the expected VA of approximately 20/25. Based on the presence of substantial cylinder in the OR and the lack of significant lens flexure, it was apparent that there was some internal source of astigmatic refractive error in the optical system. A displaced intraocular lens was the most likely cause.
Although not necessary for most cases, front-surface toric scleral and mini-scleral contact lenses offer the opportunity to provide optimal vision to those patients whose astigmatic refractive error cannot be masked by a contact lens alone. In this case, a relatively simple addition to the basic contact lens design led to a marked improvement in visual acuity for the patient. CLS
Contact Lens Spectrum, Issue: October 2010