• Diabetic macular edema is one of the major causes of loss of central vision in diabetic patients.¹
• Anti-VEGF treatment is considered as an adjunctive treatment for DME.¹
• Bevacizumab is a full-length antibody that inhibits all isoforms of the VEGF-A family.¹

OCT central macular thickness (CMT), in conjunction with VA is often used to guide decision-making in determining the treatment frequency for patients with DME.²

AIMS AND OBJECTIVE

• To determine the correlation between visual acuity and macular thickness in the treatment of Diabetic Macular Edema with Anti-VEGF therapy.

MATERIALS AND METHODS

• TYPE OF STUDY : Hospital based cross-sectional study.
• SAMPLE SIZE : 120 patients of the Diabetic Macular Edema (DME) receiving anti-VEGF treatment that reported with both VA and CMT 1 week before and 1 month after treatment.
• DURATION OF STUDY: 1 year from June 01, 2023 to May 31, 2024.
• PLACE OF STUDY : Department of Ophthalmology, Assam Medical College, Dibrugarh.

MATERIALS AND METHODS

INCLUSION CRITERIA:

• 120 patients of either gender, age between 25 to 75 years with any type, duration of diabetes mellitus and having diabetic macular edema.
• Intravitreal anti-VEGF injection as the primary intervention.
• Patients with sufficient data and informed consent.

EXCLUSION CRITERIA:

• Participants with coexisting ocular conditions, such as age-related macular degeneration, proliferative diabetic retinopathy, retinal vein occlusion, active ocular infection.
• Patients having bleeding disorder, recent myocardial infarction, uncontrolled hypertension, pregnancy and previous history of focal or grid laser.

History of previous intravitreal therapy or retinal surgery.

METHODOLOGY:

• Detailed history of the participants including onset and duration of diabetes were taken.
• Complete ophthalmological examination with fundoscopic evaluation was done using Direct and Indirect Ophthalmoscope.
• OCT was done on Topcon 3D OCT (in depth resolution- 6µ) one week prior to procedure to assess the macular thickness.
• Under all aseptic and antiseptic condition, intravitreal injection of 1.25 mg/0.05ml of Bevacizumab (Avastin) was injected 3.5-4mm from limbus under topical anaesthesia.
• Follow up was scheduled on 1^st post procedure day and after one month, BCVA of the patients were noted.
• OCT was done 1 month after the injection and changes in macular thickness were noted.  

Data was analysed using SPSS version 25.

RESULTS AND OBSERVATION

• Out of the 120 Patients, 72 were males and 48 were females. Age of patients ranged from 29 to 71 years.
• The mean duration of diabetes was 10.15 years ± 3.21 years.
• Out of 120 patients, 61 patients (50.8%) showed mean BCVA of 0.5 (logMAR chart) after one month of Intravitreal Avastin injection.
• Mean Pre Avastin macular thickness was 384.38 ± 40.51 µm and post Avastin after one month was of 323.19±32.58 µm.

Table 1: Distribution of grade of Diabetic Retinopathy among the patients studied.

Table 2 : Reduction in Macular thickness following single intravitreal injection of Avastin at one month follow up.

Fig.1: Clustered column chart showing BCVA (logMAR chart) against number of patients studied one month after Intravitreal Avastin.

Fig.2 : Bar diagram showing central macular thickness against number of patients studied after one month of Intravitreal Avastin.

Fig. 4: Pre-Avastin OCT image.

Fig. 5: Post-Avastin OCT image.

DISCUSSION

• A total of 120 patients were selected for this study and most of the patients were in their fifth decade.
• Poor financial background of the patients could be attributed to their poor diabetic control and lesser compliance towards follow up.
• We focused specifically on the correlation of VA with change in CMT and found significant relationship between the two.
• In a retrospective study by Fernando Arevalo et al, he found that primary intravitreal bevacizumab at doses of 1.25 to 2.5 mg seem to provide stability or improvement in VA, OCT, and FA in DME at 6 months.³

In a study by Gabriel Willmann et al, DME eyes show significantly lower foveal thickness than matched controls after DME resolution achieved with one-year anti-VEGF therapy.⁶

CONCLUSION

• In our study, mean pre Avastin macular thickness was 384.38 ± 40.51 micrometers and post Avastin mean macular thickness after one month was 323.19±32.58 micrometers.
• Macular thickness after one month of injection was decreased to >10% in 89 patients and <10% in 31 patients.
• 61 out of 120 patients (50.8%) showed mean BCVA of 0.5 (logMAR chart) after one month of Intravitreal Avastin injection.
• In our analysis, we have seen that there is significant improvement in macular thickness and VA following one dose of Intravitreal Avastin (statistically significant relationship between logMAR VA and CMT post intravitreal Avastin; p <0.05, calculated by ANOVA).

REFERENCES

1. Ateeq A, Tahir MA, Cheema A, Dahri A, Tareen S. Intravitreal injection of Bevacizumab in diabetic macular edema. Pak J Med Sci. 2014 Sep 30;30(6):1383–7.
2. Wang P, Hu Z, Hou M, Norman PA, Chin EK, Almeida DRP. Relationship Between Macular Thickness and Visual Acuity in the Treatment of Diabetic Macular Edema With Anti-VEGF Therapy: Systematic Review. Vol. 7, Journal of VitreoRetinal Diseases. SAGE Publications Inc.; 2023. p. 57–64.
3. Arevalo JF, Fromow-Guerra J, Quiroz-Mercado H, Sanchez JG, Wu L, Maia M, et al. Primary Intravitreal Bevacizumab (Avastin) for Diabetic Macular Edema. Results from the Pan-American Collaborative Retina Study Group at 6-Month Follow-up. Ophthalmology. 2007 Apr;114(4):743–50.
4. Eraslan S, Yıldırım Ö, Dursun Ö, Dinç E, Temel GO. Relationship between final visual acuity and optical coherence tomography findings in patients with diabetic macular EDEMA undergoing anti-VEGF therapy. Turk J Ophthalmol. 2020;50(3):163–82.
5. Tiosano L, Ayalon A, Banin E, Averbukh E, Jaouni T, Chowers I. Correlation of Response between Both Eyes to First- and Second-Line Anti-VEGF Therapy in Diabetic Macular Edema. Curr Eye Res. 2021;46(4):539–45.
6. Willmann G, Nepomuceno AB, Messias K, Barroso L, Scott IU, Messias A, et al. Foveal thickness reduction after anti-vascular endothelial growth factor treatment in chronic diabetic macular edema. Int J Ophthalmol. 2017 May 18;10(5):760–4.
7. Wang VY, Kuo BL, Chen AX, Wang K, Greenlee TE, Conti TF, et al. Fluctuations in macular thickness in patients with diabetic macular oedema treated with anti-vascular endothelial growth factor agents. Eye (Basingstoke). 2022 Jul 1;36(7):1461–7.
8. Imazeki M, Noma H, Yasuda K, Motohashi R, Goto H, Shimura M. Anti-VEGF Therapy Reduces Inflammation in Diabetic Macular Edema. Ophthalmic Res. 2021 Feb 1;64(1):43–9.