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INTRODUCTIONOptical coherence tomography (OCT) is a non-invasive, precise imaging technique that uses infrared rays to give accurate quantitative and qualitative information of the different layers of the retina. It has revolutionized the diagnosis and treatment of retinal pathologies including diabetic retinopathy and age related macular degeneration. Pupil size, refractive status, clarity of ocular media and dryness of ocular surface are some of the factors known to influence image quality in OCT. 1,2 Cataract being one of the leading causes of blindness in the world, contributes significantly to haziness of media which can affect OCT imaging. 3,4 Moreover, many of the retinal vasculopathies and degenerations requiring OCT occur more frequently in the elderly population, who are likely to have concurrent cataract. A better knowledge about the type of cataracts that can hamper the quality of scans can help clinicians identify cases where OCT has to ABSTRACT Background: Optical coherence tomography (OCT) is one of the most useful imaging techniques in the management of retinal diseases affecting the macula. Factors affecting the image quality of OCT may affect the macular thickness and hence treatment of retinal pathologies. This study was aimed to evaluate the influence of cataract on macular scans using spectral domain OCT. Methods: The prospective study was done in 36 patients with cataract. Cataract was graded as cortical, nuclear or posterior cataracts. All patients underwent small incision cataract surgery. Pre and post-operative imaging of the macula (4 weeks after surgery) using spectral domain OCT. The signal strength and central macular thickness (CMT) measurements were made before and after the surgery and analysed statistically. Results: The majority (66.7%) of patients had posterior cataracts. A statistically significant improvement in OCT image quality (as assessed by signal strength) was noted post operatively. This was maximum for posterior cataracts (2.9), followed by cortical cataract (1.6), while nuclear cataracts had the least increase in signal strength (1.3). The difference in signal strength gain between posterior and nuclear cataracts was found to be statistically significant (p = 0.05). The increase in CMT was clinically significant only in 8.2% of the study population. No patient with nuclear cataract had a clinically significant increase in CMT following surgery. Conclusions: Cataract can influence OCT image quality as well as central macular thickness measurements. Both were found to be affected maximally by posterior cataracts, followed by cortical, while nuclear cataracts had the least influence.