Ramya, M (2022) A Comparative study of LogMAR Chart Visual Acuity with Snellens Chart Visual Acuity in a Diabetic Population With and Without Maculopathy. Masters thesis, Stanley Medical College, Chennai.
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Abstract
INTRODUCTION: Diabetes Mellitus is a common global health problem among adults raising at an alarming rate. The international Diabetes federation report states that the prevalence of diabetes among adults in roll is 8.3%, which has increase to 9.9% by 2030. The goal is to attain good glycemic control with reduced risk of macro and micro viscular complication of diabetes. The values of glycated hemoglobin [HBA1C] is the gold standard assessments for glycomic control in world wide. More than 50% of people having poor glycemic control with with diabetic vascular complications. the reason for poor glycemic is lack of pharmacological and non pharmacological prescriptions. AIM OF THE STUDY: To assess the use of logMAR chart and comparing it with snellens chart in a patients with diabetic maculopathy. OBJECTIVES: To compare and quantify the difference in VA measurements between the two of the most widely used charts for VA assessment. This study gives information about rapidly emerging clinical trial and clinical case series data on treatment options for diabetic maculopathy as well as for other retinal diseases. MATERIALS AND METHODS: STUDY DESIGN: This was a cross sectional study. STUDY SETTING: The study will be carried out at department of ophthalmology in Government Stanley Medical College Hospital, Chennai. STUDY POPULATION: Sample size included to patients [140 eyes] calculated using following formula. SAMPLE SIZE CALCULATION: ● Based on the reference study. ● Formula N=2 (Za+Zb )2 SD2 (M1-m2). ● Where Za= (Statistical significant constant for 95% CI). ● Zb=0.84 (30% power). ● SD= 0.50 (standard deviation of visual acuity using logMAR chart among diabetes with maculopathy. ● M1=0.79 (Mean visual acuity using logMAR chart among diabeties with maculopathy). ● M2=0.54 (Mean visual acuity using Snellen's chart among diabetics with maculopathy). ● (M1-M2) = 0.0625 (0.25x0.25). ● On substituting on formula n=15.6 x 0.50 x 0.50 / 0.0625 n=62. ● Adding 10% non response rate n=68 (minimum sample size). Therefore sample size n=70 (1 group) & n=140 eyes (2 group). INCLUSION CRITERIA: 1. All diabetic patients with and without maculopathy age between 30 to 60 years. 2. Subjects with refractive errors < 4.00 dioptres, Astigmatism < 2.00 dioptres. 3. Diabetic population of random blood sugar (RBS) cause less than 200 mg ldl were included. EXCLUSION CRITERIA: 1. Subject with high refractive error >4.00 D dioptres Asigmatism > 20. D dioptres. 2. Patient with media opacities. 3. Patients with macular disorders 4. Patients with chronic complications other than diabetic retinopathy. 5. Diabetics with RBS >200 mg /dl. 6. Presence of acute eye conditions like conjuctivitis / uvcitis / comeal ulcer. LIMITATIONS: ● Both LOGMAR and Snellen charts results or Equivocal or interchangeable. Although we did not analyse TRV, patients with poor vision in this study were significantly more likely to have better vision on the LOGMAR chart compared to Snellen charts. ● This study has several limitations, Including the fact that the tests were performed only once, so TRV could not be evaluated. Since this study was designed to evaluate vision testing using Snellen vs LOGMAR charts and not ● TRV, repeatability and sensitivity could also not be tested in this study. The same examiner took all measurements in a short period of time under identical conditions to reduce the variability as much as possible. ● Another option would have been to move the patient closer to the Snellen chart, but since the progression is not linear, the patient would have to be continuously moved as he or she read down the chart, and correlating the final vision would have been impractical. CONCLUSION: The logMAR letter and line charts and Snellen's’s visual acuity charts are efficient enough to detect the changes in the visual acuity caused by diabetic maculopathy except the logMAR chart being tested at 4meters which was showing insignificant p value. That is differentiating presence or absence of maculopathy in diabetes mellitus patients is not always possible when logMAR line chart was used at 4 meters. ● Of the logMAR line vs logMAR letter chart’s, the letter chart is able to pick up the finer aspect of visual acuity. Hence, wrongly labeling the patient with less visual acuity value could be avoided, whenever the Snellen's 6 meter and the logMAR Line chart at 6 meter are indicative of lower visual acuity. ● So the finer tool being the letter chart of logMAR but earlier identification of ongoing maculopathy while screening is better with Snellen's’s visual acuity chart. RECOMMENDATIONS: The study recommends, 1. In mass screenings, Snellen's’s charts will be less time consuming than logMAR charts for both diabetic with and without maculopathy. 2. In a scenario rural diabetic patients failed to respond to logMAR charts, they can be educated and tested with logMAR charts for precise and accurate vision.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | 221913056 |
| Uncontrolled Keywords: | LogMAR Chart Visual Acuity with Snellens Chart Visual Acuity in a Diabetic Population With and Without Maculopathy |
| Subjects: | MEDICAL > Ophthalmology > MEDICAL > Ophthalmology |
| Depositing User: | Subramani R |
| Date Deposited: | 12 Apr 2021 01:22 |
| Last Modified: | 23 Dec 2023 05:59 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/14665 |
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