Performance of Rigid Gas Permeable (RGP) Scleral Contact Lenses With a Passive Artificial Iris

Low Vision Clinical Trial

— RGPIRIS_PA  

Official title:

Evaluation of Light Sensitivity and Visual Acuity Changes as Consequence of Rigid Gas Permeable (RGP) Scleral Contact Lenses With a Passive Artificial Iris

Clinical Trial Details — Status: Terminated

Administrative data

• NCT number: NCT04040790
• Other study ID #: RGPIRIS_PA
• Status: Terminated
• Phase: N/A
• Start date: September 16, 2019
• Est. completion date: June 22, 2021

Study information

• Verified date: November 2021
• Source: University Ghent
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Data from 15 healthy subjects will be recorded in two testing sessions spread on two days, using three lens designs (A, B and C). Before the measuring days, each subject will undergo an extra fitting session of a large-diameter scleral contact lens on the dominant eye, assessed by an experienced practitioner. The fitting data will be used to custom-make the three lens designs for each subject, thus ensuring their comfort and safety during the days of the experiments. During the experiment days baseline measurements will be obtained before and after pupil dilation and contact lens wear. During the first testing session data from the lens design A (reference lens without artificial iris) will be recorded. During the second testing session data from the lens designs B and C (lenses with artificial iris with different transmittances) will be recorded. In each testing session, contrast sensitivity and visual acuity will be evaluated and non-invasive imaging measurements will be undertaken (optical coherence tomography and slit lamp). A specific questionnaire will be given to the subject to assess comfort, light sensitivity, the horizontal visual angle and overall experience of the scleral lens and in combination with a pair of sunglasses category 3-4.

Description:

First, the participant will be subjected to an RGP scleral contact lens fitting session, then during the second and third visits the participant will be subjected to several non-invasive procedures specific to the study in order to assess contrast sensitivity and visual acuity using the fitted and uniquely fabricated investigational medical devices. The tests will be performed after eye drops are supplied to dilate the pupil of the subjects (eye drops: tropicamide and phenylephrine). Besides the clinical experiments, the participant will be given a specific questionnaire in order to assess comfort, light sensitivity, horizontal visual angle and overall experience of the investigational medical device and in combination with a pair of sunglasses category 3-4. The investigators will document the occurrence of any adverse events and specific side effects during Day 2 and 3 (testing sessions with the investigational devices) in order to effectively assess their safety.

Recruitment information / eligibility

• Status: Terminated
• Enrollment: 10
• Est. completion date: June 22, 2021
• Est. primary completion date: June 22, 2021
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 45 Years

Eligibility

Inclusion Criteria:

• Age between 18 and 45 years old

Exclusion Criteria:

• Iris disorders (i.e. ocular albinism, coloboma, aniridia).

• Known disease-related ocular surface problem (i.e. microbial keratitis).

• Known ocular pathologies (except refractive disorders).

• Coexistent ocular diseases impeding contact lens correction (i.e. glaucoma, previous ocular surgery).

• Corneal scarring.

• Low corneal endothelial cell count (< 1500 cells per mm2), with potential of corneal hypoxia-induced corneal edema induced by contact lens wear.

• Wearing of contact lenses in the last 24 hours (prior to the interventions).

Related Conditions & MeSH terms

• Low Vision
• Vision, Low

Intervention

Device:
• Scleral contact lens without a passive artificial iris
Participants wear a scleral contact lens without a passive artificial iris (Design A) on the dominant eye to perform the baseline visual performance assessment
• Scleral contact lens with a passive artificial iris with low contrast (<1:5)
Participants wear a scleral contact lens with a low contrast (<1:5) passive artificial iris (Design B) on the dominant eye to perform the baseline visual performance assessment
• Scleral contact lens with a passive artificial iris with high contrast (>1:5)
Participants wear a scleral contact lens with a low contrast (<1:5) passive artificial iris (Design B) on the dominant eye to perform the baseline visual performance assessment

Drug:
• Tropicamide and phenylephrine
Participants receive pupil dilation eye drops on the dominant eye, after baseline measurement and before wearing the scleral contact lenses (Designs A, B and C)

Locations

Country	Name	City	State
Belgium	University Hospital Ghent (UZGent)	Ghent

Sponsors (1)

Lead Sponsor	Collaborator
University Ghent

Country where clinical trial is conducted

Belgium, 

References & Publications (6)

Compañ V, Oliveira C, Aguilella-Arzo M, Mollá S, Peixoto-de-Matos SC, González-Méijome JM. Oxygen diffusion and edema with modern scleral rigid gas permeable contact lenses. Invest Ophthalmol Vis Sci. 2014 Sep 4;55(10):6421-9. doi: 10.1167/iovs.14-14038. — View Citation

Eyeson-Annan ML, Hirst LW, Battistutta D, Green A. Comparative pupil dilation using phenylephrine alone or in combination with tropicamide. Ophthalmology. 1998 Apr;105(4):726-32. — View Citation

García-Lázaro S, Ferrer-Blasco T, Radhakrishnan H, Cerviño A, Charman WN, Montés-Micó R. Visual function through 4 contact lens-based pinhole systems for presbyopia. J Cataract Refract Surg. 2012 May;38(5):858-65. doi: 10.1016/j.jcrs.2011.11.042. Epub 2012 Mar 16. — View Citation

Holden BA, Mertz GW. Critical oxygen levels to avoid corneal edema for daily and extended wear contact lenses. Invest Ophthalmol Vis Sci. 1984 Oct;25(10):1161-7. — View Citation

Pepose JS. Small-aperture contact lenses for presbyopia. J Cataract Refract Surg. 2012 Nov;38(11):2060-1; author reply 2062-4. doi: 10.1016/j.jcrs.2012.08.041. — View Citation

Xu R, Gil D, Dibas M, Hare W, Bradley A. The Effect of Light Level and Small Pupils on Presbyopic Reading Performance. Invest Ophthalmol Vis Sci. 2016 Oct 1;57(13):5656-5664. doi: 10.1167/iovs.16-20008. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Visual acuity assessment and comparison between Designs A, B and C by means of logMAR or equivalent value	Compare visual acuity values obtained with different designs	5 months from fitting session
Primary	Contrast sensitivity assessment and comparison between Designs A, B and C by means of threshold percentage or equivalent value	Compare contrast sensitivity values obtained with different designs	5 months from fitting session
Secondary	Device safety by comparing eventual adverse events with those found in scleral contact lenses	Comparing adverse event of similar devices	5 months from fitting session
Secondary	Correct fitting	Taking and analyzing ocular coherence tomography (OCT) images and slit lamp observations to estimate the clearance	5 months from fitting session
Secondary	Contact lens wear comfort, as assessed by subject data from questionnaires Rasch analyzed using a 4-Andrich ration scale model	The subjective assessment will be carried out by means of questions on 3 content areas: lens comfort (3 questions), visual quality (4 questions) and general satisfaction with the lenses (3 questions).	5 months from fitting session
Secondary	Visual acuity assessment and comparison between Designs B (low contrast) and C (high contrast) by means of logMAR or equivalent value	Comparing visual acuity between Designs B and C	5 months from fitting session
Secondary	Contrast sensitivity assessment and comparison between Designs B (low contrast) and C (high contrast) by means of threshold percentage or equivalent value	Comparing contrast sensitivity between Designs B and C	5 months from fitting session
Secondary	Horizontal visual angle	Angle at which the volunteer can see his fingers move when extending the arm (same side as dominant eye), 0°=arm extended to the side; 90°=arm straight ahead	5 months from fitting session