Evaluation of the Contrast Sensitivity Examination Test as an Early Detection of Optic Nerve Damage in Patients with Tuberculosis Using Ethambutol

Oct 13, 2025 by wbrum.org 58 views

Evaluation of the Contrast Sensitivity Examination Test as an Early Detection of Optic Nerve Damage in Patients with Tuberculosis Using Ethambutol

Introduction

Tuberculosis (TB) management has evolved significantly over the past 50 years, with Ethambutol being one of the primary drugs used in its treatment. First introduced as a first-line treatment for TB in 1961, Ethambutol was later discovered to cause optical neuropathy in 1962. Despite numerous studies, the exact mechanism of this damage remains unclear. Optical nerve damage due to Ethambutol can be reversible in a few months after treatment is stopped, but several studies have shown that around 40-50% of patients can experience permanent vision loss even after treatment cessation. The diagnosis of ocular toxicity due to Ethambutol is often carried out after symptoms appear, highlighting the need for early detection to prevent more severe vision damage. Contrast sensitivity, visual sharpness, color vision, and field field tests are some recommended tests to evaluate the effects of Ethambutol toxicity early. By conducting early detection and immediate termination of therapy, we can prevent the development of vision loss and allow visual recovery.

The Importance of Early Detection

Early detection of optic nerve damage is crucial in preventing permanent vision loss. The use of Ethambutol in TB treatment has been associated with a range of ocular side effects, including visual disturbances, color vision loss, and even permanent blindness. The exact mechanism of this damage is still not fully understood, but it is believed to be related to the drug's ability to cause oxidative stress and damage to the optic nerve. By identifying patients at risk of developing optic nerve damage early, healthcare providers can take steps to prevent or mitigate this damage, reducing the risk of permanent vision loss.

Objective

This study aims to investigate the correlation between age, gender, dose, and duration of Ethambutol therapy on the assessment of contrast sensitivity in TB patients. Contrast sensitivity is a measure of the ability to detect subtle differences in contrast between objects, and it is an important indicator of visual function. By examining the relationship between these factors and contrast sensitivity, we can gain a better understanding of the risk factors associated with optic nerve damage due to Ethambutol.

Methodology

This study is an observational analytic study involving 80 TB patients undergoing Ethambutol therapy at a dose of 15-20 mg/kg body weight per day. Patients were divided into two groups: those who used Ethambutol for less than or equal to 2 months and those who used Ethambutol for more than 2 months. Eye examinations were carried out to evaluate anterior segments, visual sharpness assessments, refraction, funduscopy, confrontation tests, and contrast sensitivity tests. Exclusion criteria included patients with other ocular or systemic diseases that could affect the results, such as cataracts, glaucoma, and various types of retinopathy. The contrast sensitivity test was carried out using a Pelli-Robson chart from a distance of 1 meter, both monocular and binocular, with a normal limit between 1.80 to 1.95. The color vision test used the Ishihara test in a uniform lighting condition, and the confrontation assessment was carried out after the measurement of intraocular pressure. Data processing was done using SPSS, with significant results if the P value was less than 0.05.

Results

The results showed that there was no significant correlation between age and a decrease in contrast sensitivity in TB patients. Similarly, there was no significant correlation between sex and decreased contrast sensitivity. The dose of Ethambutol given also did not show a significant relationship with a decrease in contrast sensitivity. However, there was a significant relationship between the duration of use of Ethambutol and a decrease in contrast sensitivity in TB patients.

Analysis

The results of this study suggest that the length of use of Ethambutol is a significant factor for the decline in contrast sensitivity. This highlights the importance of strict monitoring during Ethambutol therapy, especially in patients who have undergone treatment for more than two months. Further supervision can help in early detection of vision problems and provide opportunities for the necessary intervention.

Although there is no significant relationship with age, sex, or dose, this finding can be a guide for doctors and health workers to be more proactive in monitoring patients who use Ethambutol, especially in critical times. With early detection, the doctor can stop therapy before the optic nerve damage becomes more severe, which in turn can reduce the possibility of permanent vision loss.

Conclusion

Eye health and vision are an important part of the treatment of TB, especially for those who use Ethambutol. Early detection and proper intervention will be very beneficial for maintaining the health of the patient's vision. Given the results obtained, it is essential for medical personnel to pay more attention to the duration of Ethambutol therapy as a factor that affects contrast sensitivity, in order to optimize the management and therapy of TB patients.

Recommendations

Based on the findings of this study, the following recommendations are made:

Regular monitoring: TB patients undergoing Ethambutol therapy should be regularly monitored for signs of optic nerve damage, including contrast sensitivity tests.
Early detection: Early detection of optic nerve damage is crucial in preventing permanent vision loss. Healthcare providers should be vigilant in monitoring patients for signs of damage, especially in those who have undergone treatment for more than two months.
Adjustment of therapy: If optic nerve damage is detected, the healthcare provider should adjust the therapy to minimize the risk of further damage.
Patient education: TB patients should be educated on the importance of regular monitoring and the signs of optic nerve damage, in order to take an active role in their own care.

By implementing these recommendations, healthcare providers can reduce the risk of permanent vision loss in TB patients undergoing Ethambutol therapy.
Frequently Asked Questions (FAQs) about the Evaluation of the Contrast Sensitivity Examination Test as an Early Detection of Optic Nerve Damage in Patients with Tuberculosis Using Ethambutol

Q: What is the purpose of the contrast sensitivity examination test in patients with tuberculosis using Ethambutol?

A: The contrast sensitivity examination test is used to detect early signs of optic nerve damage in patients with tuberculosis who are undergoing Ethambutol therapy. This test can help identify patients who are at risk of developing permanent vision loss due to Ethambutol toxicity.

Q: What are the risk factors associated with optic nerve damage due to Ethambutol?

A: The risk factors associated with optic nerve damage due to Ethambutol include the duration of therapy, with longer treatment periods increasing the risk of damage. Other factors, such as age, sex, and dose, do not appear to have a significant impact on the risk of optic nerve damage.

Q: How is the contrast sensitivity examination test performed?

A: The contrast sensitivity examination test is performed using a Pelli-Robson chart from a distance of 1 meter, both monocular and binocular, with a normal limit between 1.80 to 1.95. The test is typically carried out by an eye care professional, such as an optometrist or ophthalmologist.

Q: What are the signs and symptoms of optic nerve damage due to Ethambutol?

A: The signs and symptoms of optic nerve damage due to Ethambutol can include visual disturbances, such as blurred vision, double vision, or loss of peripheral vision. Other symptoms may include color vision loss, sensitivity to light, or eye pain.

Q: How can optic nerve damage due to Ethambutol be prevented?

A: Optic nerve damage due to Ethambutol can be prevented by regular monitoring of patients undergoing Ethambutol therapy, including regular contrast sensitivity tests. Early detection of optic nerve damage can allow for prompt intervention and minimize the risk of permanent vision loss.

Q: What is the role of healthcare providers in preventing optic nerve damage due to Ethambutol?

A: Healthcare providers play a crucial role in preventing optic nerve damage due to Ethambutol by regularly monitoring patients undergoing Ethambutol therapy and adjusting treatment as needed. They should also educate patients on the importance of regular monitoring and the signs of optic nerve damage.

Q: What are the implications of the study's findings for patients with tuberculosis?

A: The study's findings highlight the importance of regular monitoring and early detection of optic nerve damage in patients with tuberculosis undergoing Ethambutol therapy. Patients should be aware of the risks associated with Ethambutol and take an active role in their own care by regularly monitoring their vision and reporting any changes to their healthcare provider.

Q: What are the next steps for further research on the evaluation of the contrast sensitivity examination test as an early detection of optic nerve damage in patients with tuberculosis using Ethambutol?

A: Further research is needed to confirm the study's findings and to explore the use of other tests and biomarkers for detecting optic nerve damage due to Ethambutol. Additionally, studies should investigate the effectiveness of different treatment strategies for preventing optic nerve damage in patients with tuberculosis undergoing Ethambutol therapy.

Q: How can patients with tuberculosis undergoing Ethambutol therapy reduce their risk of optic nerve damage?

A: Patients with tuberculosis undergoing Ethambutol therapy can reduce their risk of optic nerve damage by regularly monitoring their vision and reporting any changes to their healthcare provider. They should also follow their treatment plan as prescribed and attend regular follow-up appointments with their healthcare provider.