New findings published in Clinical Ophthalmology evaluated the tolerability of using a customized scleral lens device treatment as a drug delivery device for cyclosporine 0.05% (Restasis) to treat dry eye disease (DED).
Let’s start with this drug delivery device.
Developed by the nonprofit healthcare organization BostonSight, the Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) is a custom scleral lens medical treatment designed to restore visual/physiological function in ocular surface disease (OSD).
More specifically: The PROSE device is constructed with a removable, nickel-sized transparent dome and is composed of gas permeable plastic that enables oxygen to reach the eye’s surface.
Which eye conditions do these devices treat?
Aside from DED, the PROSE devices are also designed to treat any ectasia and ocular surface disease:
- Keratoconus
- Graft versus host disease (GVHD)
- Stevens-Johnson Syndrome (SJS)
- Sjögen’s Syndrome
- Post-corneal transplant
And how is it positioned on the eye?
The prosthetic device is placed on the sclera and jumps over the cornea (without making contact) to create a smooth surface over the distorted, damaged, or diseased cornea, according to BostonSight.
Its composition: Each device—which is applied on a patient’s eye in the morning and removed at night, before a patient goes to bed— is filled with a preservative-free saline solution.
- Notably: These devices are FDA-cleared for therapeutic indications.
What’s the intended result?
The thought is: By replacing the “ocular surface ecosystem” of the eye with an enclosed, lubricated ecosystem, a PROSE device not only provides protection to the cornea but also gives the surface tissue valuable healing time—and, for patients, pain relief.
Tell me, how is PROSE different from a scleral lens?
One major distinction: customization.
Specifically: PROSE devices have up to eight independent meridians, while scleral lenses’ customization extends to just two meridian options.
- Even further: PROSE treatment incorporates detailed contour adjustments in order to create a custom, personalized fit for each patient's eye.
Any other distinctions between the two?
The devices are also designed to be used as a comprehensive medical treatment to restore visual function in patients with complex corneal disease.
Whereas a scleral lens is limited in its diameter offerings, the PROSE treatment utilizes a “fully custom prosthetic scale device ranging from 14 mm to 23 mm” as well as the expertise of both a PROSE-trained optometrists and an ophthalmologist.
Alrighty, now to this research…talk participants.
Over a 14-month-period, this open-label, prospective, non-comparative clinical trial enrolled 14 patients (aged 18+) diagnosed with DED.
About these participants: All patients were required to be current, bilateral, daily wearers of PROSE for more than 6 months as well as have a:
- Baseline ocular surface disease index (OSDI) of 13 or higher
- Baseline corneal fluoresceine staining (CFS) of 2 or greater (when combining both eyes’ scores)
And the study setup?
At the start of the study, all participants were either already using or willing to transition to a buffered preservative-free, normal saline as the PROSE reservoir solution (PuriLens, The LifeStyle Company, Inc).
Important to note: These patients were split into two groups based on this distinction:
- Group A: Habitual PuriLens users
- Started on cyclosporine 0.05% at the start of the study and instructed to instill one drop in the PROSE reservoir and then fill the remaining area with PuriLens
- After applying and wearing PROSE for 6 hours, the device was removed and the process repeated for an additional 4 hours
- Group B: Non-PuriLens users
- Discontinued their current daily PROSE reservoir-filling solution and provided with PuriLens to use exclusively in the reservoir for 2 weeks (visit 1a)
- After this, patients were started on cyclosporine 0.05% with identical instructions to Group B (visit 1b)
- Discontinued their current daily PROSE reservoir-filling solution and provided with PuriLens to use exclusively in the reservoir for 2 weeks (visit 1a)
When were these patients examined?
Examinations were conducted prior to patients beginning the dosing regimens (visit 1 for Group A and visits 1a/b for Group B) as well as at the 1-week (visit 2) and 4-week (visit 3) mark following dispensing of cyclosporine 0.05%.
At each visit, patients were assessed (visit 1) and reassessed (visits 2 and 3) for:
- Measurement of bulbar conjunctival injection with PROSE on the eye
- Measured via automated Keratograph 5M R-Scan (Oculus)
- Visual acuity with PROSE
- Via slit-lamp:
- Ocular surface
- Conjunctival redness
- CFS
- Conjunctival lissamine staining
And following that third visit?
Participants were then instructed to discontinue using cyclosporine 0.05% and return to their standard solution regimen from before the study.
Next up: the results.
Out of the 14 initial participants enrolled, 4 failed screening and 1 failed to complete the study (due to the only adverse event of the study: ocular burning and stinging).
As a result: 18 eyes (9 participants aged 38 to 73, 4 of whom were female) were evaluated.
- Of this number: All patients had DED while seven also had corneal ectasia
How did OSDI fare?
By the one-month visit: Total OSDI scores decreased (i.e., improved) by an average of 3.83 ± 6.87 from baseline (p = 0.07).
- Maximum OSDI improvement: 16.7 decrease (for one participant)
- Maximum OSDI worsening: 6.24 increase (for one participant)
Notably: There was no statistically significant change in best-corrected visual acuity (BCVA).
- Mean BCVA (logMAR) at baseline: 0.359 ±0.261
- Mean BCVA (logMAR) at one-week visit: 0.393 ±0.320 (p= 0.16)
- Translation: Worsened
- Mean BCVA (logMAR) at one-month visit: 0.353 ± 0.320 (p = 0.42)
- Translation: Minimally improved versus baseline
What about corneal and conjunctival staining?
Investigators noted that, without comparing with placebo, a statistically significant improvement (p < 0.05) “in mean per subject and mean per eye corneal fluorescein staining, conjunctival lissamine staining, and conjunctival hyperemia by slit lamp examination at one-month follow-up.”
- See the full data for a closer look.
And how did patients rate the difficulty of the PROSE treatment to use?
Based on a scale of 0 (extremely difficult) to 10 (extremely easy), participants reported an average score of 9.56 ±0.88.
As a result of this, the study authors stated that “this data set supports the practicality of such a drug delivery system for home use.”
Any limitations?
A few were listed in association with the PROSE drug delivery method, including:
- Tear exchange occurred between the external tear film and reservoir solution throughout the duration of PROSE wear time
- Rate of exchange was not measured
- Composition of the tear film varied
- Final drug concentration varied for each PROSE used by patients
- This is due to the customization capabilities of each device
So what’s the conclusion of this data?
Overall, the use of PROSE as a drug delivery system for cyclosporine 0.05%was deemed to be “well tolerated in regards to both ocular symptoms and ocular surface signs” as well as suggestive in its efficacy.
Now the takeaway.
While the study authors noted investigation into PROSE or scleral lenses as drug delivery systems for preservative-free ocular topical medications is “still in the infancy,” they concluded:
“This pilot study reports encouraging symptom and ocular surface tolerability for cyclosporine 0.05% when delivered via a PROSE reservoir.”
Plus: Additional research is still needed to determine the safety and efficacy of using this combination for DED treatment.
And what’s next?
The authors concluded that this data supports a larger scale randomized, controlled, double-blinded prospective clinical trial.