Clinical Safety & Efficacy Data
U.S. Clinical Studies
Two multi-year clinical studies have been conducted to evaluate the safety and efficacy of the telescope prosthesis used in the CentraSight treatment program: the IMT-002 pivotal safety and efficacy study and the IMT-002-LTM long-term monitoring safety study.(1)
Pivotal Study
The 2-year, prospective, 28-center IMT-002 pivotal study (n=217) evaluated the safety and effectiveness of the telescope prosthesis for the improvement of visual acuity in patients with bilateral moderate to profound central vision impairment (best corrected distance visual acuity (BCDVA) between 20/80 and 20/800) due to untreatable End-Stage age-related macular degeneration (AMD).(2)
Efficacy Results
The telescope prosthesis improved visual acuity and quality of life in subjects with End-Stage AMD. The primary effectiveness endpoint, a 2-line or greater gain in either distance or near best corrected visual acuity (BCVA) at 12 months in at least 50% of study subjects, was met and exceeded. The secondary effectiveness outcome measure, improvement in quality of life, was also improved by clinically significant levels.
Visual Acuity Primary Endpoint
Ninety percent of telescope-implanted eyes achieved at least a 2-line or greater gain in either distance or near BCVA at 12 months, thus exceeding the 50% criterion specified for the primary endpoint. This criterion was also exceeded at 24 months.
At least 50% of telescope-implanted eyes were required to improve ≥ 2 lines of best-corrected distance or near visual acuity (BCDVA or BCNVA). In the study, 90.1% of patients achieved this level of improvement.
Long-Term Visual Acuity
Long-term follow up data from the IMT-002-LTM study demonstrated mean BCDVA improvements were generally retained at 36 and 48 months in telescope-implanted eyes. Mean BCDVA was maintained between 12 and 48 months, with BCDVA at 48 months within 2 line of BCDVA at 12 months.
Clinically meaningful visual acuity benefit demonstrated through 2-year follow up. 60% of patients gained better than 3 lines of best-corrected distance visual acuity (BCVA).
Quality of Life Assessment
Quality of life, as assessed by the National Eye Institute Visual Functioning Questionnaire-25 (VFQ-25), was a secondary outcome measure. The VFQ-25 is a validated version of the National Eye Institute Visual Functioning Questionnaire (VFQ) which measures vision-targeted health status for persons with chronic eye diseases including macular degeneration. A 5-point difference in subscale and/or composite scores may be interpreted as clinically significant. (3-5)
The VFQ-25 survey was administered at baseline and postoperatively. The results demonstrate that implantation with the telescope prosthesis improved quality of life in this study population (subjects with End-Stage AMD and significant bilateral vision impairment).
The mean overall composite score, as well as the scores for almost all relevant subscales, achieved a clinically significant level. Not only was there an improvement in vision-specific subscales, which would be expected with a doubling of visual acuity, there was also a significant improvement on the psychosocial vision-targeted dependency, mental health, role difficulties, and social functioning subscales. Results suggest that patients are less dependent on others, less worried or frustrated with their visual acuity, less limited in their activities related to visual acuity, more able to visit with others, and better able to recognize facial expressions.(1)
Outcomes for subscales of the VFQ-25 (except driving): At 12 months, the mean VFQ-25 composite score increased by a clinically significant amount (an increase of 6 points at 12 months). Overall, seven of the VFQ-25 subscales improved by clinically significant levels (general vision, near activities, distance activities, social functioning, mental health, role difficulties, and dependency). Note: The telescope prothesis limits peripheral vision in the implanted eye (as a trade-off for improved central vision) and this is reflected by a decrease in the peripheral vision subscale. Driving was not a target subscale in this older, End-Stage AMD patient population.
Complications
A total of 217 subjects were evaluated in the IMT-002 clinical trial. A total of 206 eyes were implanted with the telescope prosthesis and followed for 24 months. 129 patients were enrolled in the IMT-002-LTM long-term monitoring trial for which 4-year safety data was available.
Ocular complications encountered during the studies included endothelial cell loss, inflammatory/pigment deposits, transient cornea edema, and IOP elevation.
Telescope-implanted eyes demonstrated a biphasic pattern of endothelial cell loss-'fast' then 'slow' - similar to the pattern reported by Bourne and Armitage following traditional cataract surgery. (8,9)
Professional Use Information and Long-Term Monitoring Data
Full prescribing information, safety and efficacy data, and long-term monitoring data after telescope implantation are available in the Professional Use Information.
