While both corneal gas permeable and scleral lenses have been show to improve visual
acuity in individuals with keratoconus, it has yet to be determined if one option has
superior comfort and overall patient satisfaction in patients new to gas permeable lens
use. In this study, patients will be prospectively fit with both corneal gas permeable
and scleral lenses according to standard clinical practice. Both corneal gas permeable
and scleral lenses are considered standard of care for patients with keratoconus.
The investigators hypothesize that study participants will select scleral lens over
corneal gas permeable lens as their preferred final lens type of choice.
The Primary outcome measure of this study is participant selected final lens choice for
continued use for the management of keratoconus.
Methods:
Study Design This is a prospective, multi-center, randomized interventional clinical
trial with a 2x2 crossover design of patients with keratoconus fit with corneal and
scleral gas permeable contact lenses. The crossover design allows intra-subject
differences between two randomized groups with participants serving as their own
controls. Contact lens #1 will be the SynergEyes VS (Synergeyes, Inc., Carlsbad CA) which
features bi-tangential toric peripheries with linear landing zones. The standard lens is
16.0mm and is available from 14.5 to 17.5mm diameters. Contact lens #2 will be the RoseK2
corneal gas permeable lens (Blanchard Contact Lens, Inc. Manchester, NH). The lens is
available in with a base curve range from 4.30 to 8.60 mm, diameter of 7.90 to 10.40mm.
Inclusion Criteria
Age 18 or older.
Diagnosis of keratoconus.
Available baseline corneal topography and pachymetry
Amsler-Krumeich keratoconus classification of stage 1 or higher
Exclusion Criteria
No prior corneal transplantation or INTACTS
No prior use of hybrid, corneal or scleral gas permeable lenses
Presence of corneal scarring
Study procedures During the initial study visits patient demographics, past ocular and
medical history and best corrected visual acuity with manifest refraction will be
recorded. Additional testing may include corneal topography, pachymetry and meibography.
Dry eye symptoms and contact lens comfort will be assessed using the OSDI and CLDEQ
questionnaires.
Participants will be fit according to standard practices with the RoseK 2 corneal gas
permeable and Synergeyes VS scleral lenses following manufacturer's recommendations. Over
refraction and best corrected visual acuity will be recorded. Subjective comfort with
lens use rated on comfort scale of 0 (not comfortable) to 10 (very comfortable).
Participants will be randomized to dispense lens #1 vs lens #2. They will be trained in
safe application and removal and provided instructions on lens disinfection procedures.
Best corrected visual acuity with lens #1 and subjective comfort with lens use will be
rated on comfort scale of 0 (not comfortable) to 10 (very comfortable).
At the next visit, participants will return wearing lens #1 for minimum of 3 hours. Best
corrected visual acuity with lens #1 will be recorded as well as hours of lens wear
today, average hours of lens wear time, days per week of per week and daily time spent on
lens application and removal. They will rate subjective comfort with lens use on comfort
scale of 0 (not comfortable) to 10 (very comfortable). Dry eye symptoms will be assessed
using OSDI and CLDEQ questionnaires. Participants will be trained in application and
removal with lens #2. Best corrected visual acuity with lens #2 and subjective comfort
will be rated on comfort scale of 0 (not comfortable) to 10 (very comfortable).
At the final visit, participants will return wearing lens #2 for minimum of 3 hours. Best
corrected visual acuity with lens #2 will be recorded as well as hours of lens wear
today, average hours of lens wear time, days per week of per week and daily time spent on
lens application and removal. They will rate subjective comfort with lens use on comfort
scale of 0 (not comfortable) to 10 (very comfortable). Dry eye symptoms will be assessed
using OSDI and CLDEQ questionnaires. Participants will be trained in application and
removal with lens #2. Best corrected visual acuity with lens #2 and subjective comfort
will be rated on comfort scale of 0 (not comfortable) to 10 (very comfortable).
The participant will make a final selection of lens of choice #1 or #2.