Astigmatism
Conditions
Keywords
astigmatism, toric contact lens, axis misalignment, visual acuity
Brief summary
Toric SCL combined spheric lens power with cylinder power and axis. However, in Indonesia, the availability of cylinder power and axis parameter variations between products are still narrow, with stock-keeping units (SKUs) options only between 0.75-2.75 DC and 10o-180o for power and axis, respectively. Providing accurate toric SCL prescription for astigmatism patient in Indonesia remains a challenge for ophthalmologists and generally could not be achieved. Therefore, the aim of this study is to investigate the effect of power undercorrection and axis misalignment on visual acuity, contrast sensitivity, visual clarity, visual satisfaction, and vision acceptability. The inclusion criteria for the trial, include: (1) 20 to 40 years of age without the need for presbyopic correction, (2) mild to moderate myopia patients, sphere between -1.00 and - 6.00 D combined with cylinder between -0.75 to -3.00 DC in at least one eye, (3) corrected distance visual acuity (VA) of with Toric SCL 6/15 or better bilaterally. Exclusion criteria include: (1) a history of contact lens use 6 months prior to trial, (2) history of previous ocular surgery, (3) anterior and posterior segment abnormalities, (4) manifest strabismus or dry eye, and (5) ocular and systemic diseases that would preclude CL wear or decrease visual acuity; and pregnancy or lactation.
Detailed description
Detailed Procedure Baseline refraction and clinical manifestations were determined during initial visit which each participants attended three assessment visits on a separate day. Baseline visual acuity was measured using Snellen chart, contrast sensitivity was measured using Pelli-Robson chart, and VAS (Visual Analog Scale, with 10 being the best indicator) was utilized to measure monocular clarity (1=blurred, 10=clear), satisfaction (1=satisfied, 10=unsatisfied), and vision acceptability (1=unacceptable, 10=perfectly acceptable). Participants were fitted on their diseased eye, which could be unilateral or bilateral, with the toric SCL. Lens fit (corneal coverage, centration, movement, and rotation) was examined using slit-lamp examination. Regarding lens rotation, modification of the toric SCL axis was determined using the LARS (left add, right subtract) method for proper contact lens fitting. The shifting axis in toric SCL was assessed by observing the shift marker on contact lens in a clockwise or anticlockwise direction; then if any, it was corrected using LARS formula. A disposable toric lens investigated in this work is 2-Weeks Acuvue Moist for Astigmatism (2WAMfA), a common hydrogel conventional toric lenses. The assessment visits interval is 1 week and completed exactly on day 14 after their first baseline visit. At each assessment visit, three different cylinder power were tested: 1) full cylinder power, 2) under-correction of cylinder power by 0.5 D, and 3) under-correction of cylinder power by 1.0 DC. Axis was also misaligned by -10° and +10° for each cylinder power alteration. The powers and axis assigned to the participants were randomized during every assessment visit. Baseline assessments and treatment allocations were masked to both patients and physician. All assessments were carried out on the day of observation and recorded on the subject evaluation sheet in accordance with the sample data, in which examinations results.
Interventions
DEVICEHydrogel conventional toric lenses with -10° axis misalignment
The assessment visits interval is 1 week and completed exactly on day 14 after their first baseline visit. At each assessment visit, three different cylinder power were tested: 1) full cylinder power, 2) under-correction of cylinder power by 0.5 D, and 3) under-correction of cylinder power by 1.0 DC. Axis was also misaligned by -10° and +10° for each cylinder power alteration. The powers and axis assigned to the participants were randomized during every assessment visit. Baseline assessments and treatment allocations were masked to both patients and physician. All assessments were carried out on the day of observation and recorded on the subject evaluation sheet in accordance with the sample data, in which examinations results.
DEVICEHydrogel conventional toric lenses with +10° axis misalignment
The assessment visits interval is 1 week and completed exactly on day 14 after their first baseline visit. At each assessment visit, three different cylinder power were tested: 1) full cylinder power, 2) under-correction of cylinder power by 0.5 D, and 3) under-correction of cylinder power by 1.0 DC. Axis was also misaligned by -10° and +10° for each cylinder power alteration. The powers and axis assigned to the participants were randomized during every assessment visit. Baseline assessments and treatment allocations were masked to both patients and physician. All assessments were carried out on the day of observation and recorded on the subject evaluation sheet in accordance with the sample data, in which examinations results.
DEVICEHydrogel conventional toric lenses with undercorrection of 0.5 D
The assessment visits interval is 1 week and completed exactly on day 14 after their first baseline visit. At each assessment visit, three different cylinder power were tested: 1) full cylinder power, 2) under-correction of cylinder power by 0.5 D, and 3) under-correction of cylinder power by 1.0 DC. Axis was also misaligned by -10° and +10° for each cylinder power alteration. The powers and axis assigned to the participants were randomized during every assessment visit. Baseline assessments and treatment allocations were masked to both patients and physician. All assessments were carried out on the day of observation and recorded on the subject evaluation sheet in accordance with the sample data, in which examinations results.
DEVICEHydrogel conventional toric lenses with undercorrection of 1.0 D
The assessment visits interval is 1 week and completed exactly on day 14 after their first baseline visit. At each assessment visit, three different cylinder power were tested: 1) full cylinder power, 2) under-correction of cylinder power by 0.5 D, and 3) under-correction of cylinder power by 1.0 DC. Axis was also misaligned by -10° and +10° for each cylinder power alteration. The powers and axis assigned to the participants were randomized during every assessment visit. Baseline assessments and treatment allocations were masked to both patients and physician. All assessments were carried out on the day of observation and recorded on the subject evaluation sheet in accordance with the sample data, in which examinations results.
Sponsors
Indonesia University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DEVICE_FEASIBILITY
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
The participants, the ophthalmologist conducting the eye examinations, and the outcome assessors will be blinded to group allocation.
Intervention model description
This study will compare the effect of undercorrection and axis misalignment of toric SCL in mild and moderate astigmatism on visual acuity, contrast sensitivity, visual satisfaction, and vision acceptability.
Eligibility
Sex/Gender
ALL
Age
20 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
1. 20 to 40 years of age without the need for presbyopic correction 2. mild to moderate myopia patients, sphere between -1.00 and - 6.00 D combined with cylinder between -0.75 to -3.00 DC in at least one eye 3. corrected distance visual acuity (VA) of with Toric SCL 6/15 or better bilaterally.
Exclusion criteria
1. a history of contact lens use 6 months prior to trial 2. history of previous ocular surgery 3. anterior and posterior segment abnormalities 4. manifest strabismus or dry eye 5. ocular and systemic diseases that would preclude CL wear or decrease visual acuity; and pregnancy or lactation.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Vision acceptability | Week 1 and week 2 | VAS (Visual Analog Scale, with 10 being the best indicator) was utilized to measure vision acceptability (1=unacceptable, 10=perfectly acceptable). |
| Visual acuity | Week 1 and week 2 | Visual acuity was measured using Snellen chart and reported with logMAR |
| Contrast sensitivity was measured using Pelli-Robson chart, | Week 1 and week 2 | Contrast sensitivity was measured using Pelli-Robson chart, |
| Monocular clarity | Week 1 and week 2 | VAS (Visual Analog Scale, with 10 being the best indicator) was utilized to measure monocular clarity (1=blurred, 10=clear) |
| Visual satisfaction | Week 1 and week 2 | VAS (Visual Analog Scale, with 10 being the best indicator) was utilized to measure visual satisfaction (1=satisfied, 10=unsatisfied) |
Countries
Indonesia
Outcome results
None listed