Pan African Clinical Trials Registry
South African Medical Research Council, South African Cochrane Centre
PO Box 19070, Tygerberg, 7505, South Africa
Telephone: +27 21 938 0506 / +27 21 938 0834 Fax: +27 21 938 0836
Email: pactradmin@mrc.ac.za Website: pactr.samrc.ac.za
Trial no.: PACTR202407520039845 Date of Approval: 18/07/2024
Trial Status: Retrospective registration - This trial was registered after enrolment of the first participant
TRIAL DESCRIPTION
Public title Effect of absorptive filters compared to refractive correction on contrast sensitivity among primary open-angle glaucoma patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria.
Official scientific title Effect of absorptive filters compared to refractive correction on contrast sensitivity among primary open-angle glaucoma patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria.
Brief summary describing the background and objectives of the trial Glaucoma is a group of progressive optic neuropathies that are characterized by the degeneration of retinal ganglion cells (RGC) and thinning of the retinal nerve fiber layer (RNFL) in the presence of elevated or normal intraocular pressure (IOP). According to the Nigeria National Blindness and Visual Impairment Survey (NNBVIS 2005-2007), glaucoma has a prevalence of 5.02%. Though, glaucoma is asymptomatic at the early stage, several studies have reported impaired contrast sensitivity (CS) at the early and late stages. The study aims to assess the effect of different absorptive filters on contrast sensitivity compared to refractive correction among primary open-angle glaucoma patients. 1. To assess unaided contrast sensitivity in control and study groups of primary open-angle glaucoma patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. 2. To assess best corrected contrast sensitivity in the control group (with refractive correction alone) and study group (with both refractive correction and different absorptive filters) among primary open-angle glaucoma patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. 3. To compare unaided and best-corrected contrast sensitivity with refractive correction alone in control group. 4. To compare unaided and best-corrected contrast sensitivity with both refractive correction and different absorptive filters in the study group. 5. To compare the effect of refractive correction alone on contrast sensitivity with the effect of both refractive correction and different absorptive filters among primary open-angle glaucoma patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. 6. To identify factors associated with impaired contrast sensitivity among primary open-angle glaucoma patients at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria.
Type of trial RCT
Acronym (If the trial has an acronym then please provide)
Disease(s) or condition(s) being studied Eye Diseases
Sub-Disease(s) or condition(s) being studied
Purpose of the trial Supportive care
Anticipated trial start date 03/06/2024
Actual trial start date 03/06/2024
Anticipated date of last follow up 30/09/2024
Actual Last follow-up date 30/09/2024
Anticipated target sample size (number of participants) 200
Actual target sample size (number of participants) 200
Recruitment status Not yet recruiting
Publication URL
Secondary Ids Issuing authority/Trial register
ERC20230906 Ethics and Research Committe Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife
STUDY DESIGN
Intervention assignment Allocation to intervention If randomised, describe how the allocation sequence was generated Describe how the allocation sequence/code was concealed from the person allocating the participants to the intervention arms Masking If masking / blinding was used
Crossover: all participants receive all interventions in different sequence during study Randomised Simple randomization using a randomization table created by a computer software program Central randomisation by phone/fax Masking/blinding used Care giver/Provider,Outcome Assessors,Participants
INTERVENTIONS
Intervention type Intervention name Dose Duration Intervention description Group size Nature of control
Experimental Group study group No dosage Till the same size is met A Snellen chart will assess each participant's unaided, and spectacle visual acuity. A Pelli-Robson contrast sensitivity chart will be used to measure the participants' unaided vision, with refractive correction alone and with both the refractive correction and different absorptive filters (amber, blue, brown, green, grey, silver, black, and yellow) will be assessed randomly. This eliminates fatiguability as filters are assessed. The procedure for contrast sensitivity involves participants sitting at a distance of 1 metre away from the chart with the centre of the chart approximately at their eye level. With the left eye padded with an eye patch, participants will identify each letter on the Pelli Robson chart starting with the darkest letters in the upper left-hand corner and reading horizontally across the entire line. Participants will be encouraged to guess even when they believe that the letters are invisible and several seconds will be allowed for the faintest letters to appear. Testing is stopped when the participant has guessed incorrectly 2 of the 3 letters in a triplet. The test will be repeated three times and the average score will be noted. The same procedure will be repeated testing the left eye and the two eyes at the same time. With the participant wearing a trial frame that has the participant’s distant refractive correction, the assessment of contrast sensitivity using Pelli-Robson CS chart will be performed, starting with the right eye, left eye and lastly the two eyes. This will be done three times and the average score will be noted. Both the refractive correction and absorptive filters will be used to measure contrast sensitivity in the same order. The contrast sensitivity score of each step will be recorded. The preferred filters will be used to assess distance and near visual acuity. 100
Control Group control group No dosage Till the same size is met A Snellen chart will assess each participant's unaided, and spectacle visual acuity. A Pelli-Robson contrast sensitivity chart will be used to measure the participants' unaided vision, with refractive correction alone and with both the refractive correction and different absorptive filters (amber, blue, brown, green, grey, silver, black, and yellow) will be assessed randomly. This eliminates fatiguability as filters are assessed. To eliminate bias, a form of triple-blind masking will be done. All the participants (glaucoma patients) will undergo the same procedure which includes assessing their contrast sensitivity with spectacle correction only and then with spectacle correction and absorptive filters. This will eliminate participants' bias. At the level of the investigator, carrying out the same procedure for all participants will eliminate the influence of encouragement or bias in scoring the participants i.e. favoring some participants and scoring others low. Finally, to control for data analyst bias, a web-based random generator app will randomly and non-repetitively generate 100 numbers which will be the experimental group (Contrast sensitivity score of spectacle only and with both spectacle and filters will be analyzed). The remaining 100 un-generated numbers are termed the control group (only the CSS of the spectacle will be analyzed) and the CSS obtained from both spectacle and filters will not be analyzed. 100 Active-Treatment of Control Group
ELIGIBILITY CRITERIA
List inclusion criteria List exclusion criteria Age Category Minimum age Maximum age Gender
1. Glaucoma patients that are 40 years and older and diagnosed more than a year ago. 2. Has primary open-angle glaucoma. 3. Has visual acuity better or equal to logMAR of 1.00 (6/60) in the worse eye. 4. Has a recent (not more than 6 months) central visual field report with reliable indices 1. The presence of media opacities precluding visualization of the fundus such as corneal pathology, visually significant cataracts (grade 2 or higher lens morphology according to the Lens Opacities Classification System II (LOCS II), the presence of significant posterior capsular opacity, vitreous opacities, and hemorrhages. 2. A history of ophthalmic surgeries (corneal refractive, cataract and vitreoretinal surgeries) that can decrease contrast sensitivity. 3. The presence of macular or retinal disease (age-related macular degeneration and retinal dystrophies) that can decrease contrast sensitivity. 4. Patients on drugs affecting pupillary size (miotic or mydriatic drugs) that can decrease contrast sensitivity. 5. Poor vision precluding the ability to fixate on the desired target. 6. The presence of neurological diseases like Parkinson's disease, and Alzheimer’s disease. 80 and over: 80+ Year,Aged: 65+ Year(s),Middle Aged: 45 Year(s)-64 Year(s) 40 Year(s) 100 Year(s) Both
ETHICS APPROVAL
Has the study received appropriate ethics committee approval Date the study will be submitted for approval Date of approval Name of the ethics committee
Yes 19/05/2024 Obafemi Awolowo university Teaching Hospitals Complex
Ethics Committee Address
Street address City Postal code Country
Ile-Ife Ile-Ife 220103 Nigeria
OUTCOMES
Type of outcome Outcome Timepoint(s) at which outcome measured
Primary Outcome Contrast sensitivity score The point the participant missed two out of the letters twice, that corresponding point is the participant best contrast sensitivity score - Outcome measure
Secondary Outcome Visual acuity with the desired filters The point when the best absorptive filters is used to assess the visual acuity using Snellen chart to get the visual acuity score with preferred filter- Outcome measure
RECRUITMENT CENTRES
Name of recruitment centre Street address City Postal code Country
Obafemi Awolowo University Teaching Hospitals Complex Ile-Ife OsunState 220103 Nigeria
FUNDING SOURCES
Name of source Street address City Postal code Country
Adelabu Kafayat Omobola Olatunbosun House, Ori-Owo Line 4, Olubukun, Ile-Ife Osunstate 220103 Nigeria
SPONSORS
Sponsor level Name Street address City Postal code Country Nature of sponsor
Primary Sponsor Adelabu Kafayat Omobola Olatunbosun House, Ori-Owo Line 4, Olubukun, Ife-City IleIfe 220103 Nigeria Individual
COLLABORATORS
Name Street address City Postal code Country
CONTACT PEOPLE
Role Name Email Phone Street address
Principal Investigator Kafayat Adelabu kafdelab@gmail.com +2347062314363 Olatunbosun House, Line 4, Ori-Owo, Olubukun, Ife-City
City Postal code Country Position/Affiliation
IleIfe 220103 Nigeria Principal Investigator
Role Name Email Phone Street address
Scientific Enquiries Bolajoko Adewara bolajoko.adewara@gmail.com +2347033053135 Doctors Quarters, Road 7, Obafemi Awolowo Univeristy close, Ile-ife
City Postal code Country Position/Affiliation
Osunstate 221003 Nigeria senior lecturer
Role Name Email Phone Street address
Public Enquiries Bernice Adegbehingbe berniceola2003@yahoo.com +2348037218094 Doctors quarters, Road 13, Obafemi Awolowo University Close, Ile-Ife
City Postal code Country Position/Affiliation
Osun state 220103 Nigeria Professor
REPORTING
Share IPD Description Additional Document Types Sharing Time Frame Key Access Criteria
Yes The de-identified individual participant data sharing statement containing the following (the contrast sensitivity score assessed with the participant's unaided vision, spectacle, spectacle and different filters at the same time), the participant's unaided vision, visual acuity with spectacles and visual acuity with the filters that give the best contrast sensitivity score, ocular examination, central visual field report, fundoscopy findings, and their intraocular pressures will be stored in an Excel spreadsheet on the principal investigator passworded laptop and uploaded to the appropriate website for public use. This will be available within 12 months of the study completion of the study. The data will be freely accessible to the general public for any purpose of their choice and without time frame limitation. Analytic Code,Clinical Study Report,Statistical Analysis Plan,Study Protocol Within 12 months of the completion of the study Key access criteria is not yet available
URL Results Available Results Summary Result Posting Date First Journal Publication Date
No address now No
Result Upload 1: Result Upload 2: Result Upload 3: Result Upload 4: Result Upload 5:
Result URL Hyperlinks Link To Protocol
Result URL Hyperlinks
Changes to trial information