Visual Optics and Psychophysics Laboratory

Visual Optics and Psychophysics Laboratory

Image courtesy: Fourier Optics Calculator developed by Prof Larry Thibos of the Indiana University School of Optometry

The Visual Optics and Psychophysics Laboratory was established at the Hyderabad campus of the Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute in the year 2009 by Dr Shrikant Bharadwaj. The lab has three major themes of research:

  1. To understand the impact of distortions in the eye on the perception of form and depth vision.
  2. To understand how the visual system adapts to the presence of such optical distortions experienced over extended periods of time.
  3. To develop instrumentation and technology for non-invasive measurement of the refractive power of the eye.

The lab uses human disease and iatrogenesis models for studying these focal themes. Non-invasive measurements of wavefront aberrometery, psychophysics and computational reconstruction of image quality are performed on patients with corneal disease like keratoconus and cataract and surgical procedures like corneal transplants, refractive surgery to understand the distortions experienced in the eye and their perception of form and depth vision. The understanding gained from these measurements will eventually be translated into newer modalities of diagnosis and management of eye disorders in the clinic. The entire enterprise is driven through active collaboration with colleagues from clinical ophthalmology and optometry, delivering high-quality patient care at the Hyderabad campus of the LVPEI.

The Team

  • Shrikant R Bharadwaj
  • Preetirupa Devi, Senior Research Optometrist
  • Tithi Bhakta, Project Optometrist
  • Ketakee Jain, Project Optometrist
  • Rahul Negi, Consultant Optometrist
  • Indrani Sirivella, Project Optometrist

Past Lab Members

  • Preetam Kumar - Post-doctoral research fellow, University of Houston College of Optometry, Houston, USA.
  • C Vijay Reena Durai - Clinical research associate, Remidio Innovative Solutions Pvt Ltd, Bengaluru, India
  • Bhagya Lakshmi Marella - Post-doctoral research fellow, Indiana University School of Optometry, Bloomington, USA
  • Praveen Kumar Bandela - Post-doctoral research fellow, nthalmic Pvt Ltd, Hyderabad, India
  • Vinay Kumar Nilagiri - Post-doctoral research fellow at University of Western Australia, Perth, Australia
  • Chandrika Ravisankar - PhD student at SRM Institute of Science and Technology, Chennai, India
  • Samrat Sarkar - PhD student at University of New South Wales, Sydney, Australia
  • Nakka Geetha Sravani - PhD student at University of New South Wales, Sydney, Australia
  • Asra Fatima - PhD student at University of Hyderabad School of Medical Sciences, Hyderabad, India
  • Veerendranath Pesala - Consultant Optometrist, L V Prasad Eye Institute, Hyderabad, India.
  • Sabyasachi Goswami - PhD student at the Department of Brain and Cognitive Sciences - University of Rochester.
  • Swaathi Balaji
  • Avina Patel

Relevant Publications

  1. Kumar, P., Campbell, P., Vaddavalli, P. K., Hull, C. C., & Bharadwaj, S. R. (2023). Structure-Function Relationship in Keratoconus: Spatial and Depth Vision. Translational Vision Science and Technology. In Press.
  2. Ravisankar, C., Tyler, C. W., Schor, C. M., & Bharadwaj, S. R. (2023). Success rates, near-response patterns, and learning trends with free-fusion stereograms. Vision Research. 214:108329.
  3. Goswami, S., & Bharadwaj, S.R. (2023). Temporal fluctuations in defocus restore the acuity loss encountered with uncorrected refractive error. Journal of Optical Society of America A. 40(11):2008 – 2018.
  4. Negi, R., Raviselvan, M., Yarravarapu, D., Chillakala, K., Reena Durai, C. V., Baskar, J., Jain, A., Bisht, K., Bhate, M., & Bharadwaj, S. R. (2023). Severity of relative afferent pupillary defect is dependent on the intensity of pupillary light stimulation. Optometry and Vision Science. In Press.
  5. Kumar, P., Vaddavalli, P. K., Campbell, P., Hull, C. C., & Bharadwaj, S. R. (2023). Suprathreshold contrast perception of resolvable high spatial frequencies remain intact in keratoconus. Vision Research, 212 (2023) 108310.
  6. Narayanan, A., Ramani, K. K., Radhakrishnan, A., Satgunam, P., Lakshminarayanan, V., & Bharadwaj, S. R.* (2023). Optometry in India: Vision of Professor Jay M Enoch and its present status. Asian Journal of Physics, 32 (5 – 8): 127 – 135.
  7. Marella, B., Vaddavalli, P., Reddy, J., Conway, M., Suttle, C., & Bharadwaj, S. R.* (2023). Interocular contrast balancing partially improves stereoacuity in keratoconus. Optometry and Vision Science. 100(4):239-247.
  8. Goswami, S., & Bharadwaj, S. R. (2023). Impact of temporal fluctuations in optical defocus on visual acuity: Empirical results and modeling outcomes. Journal of Vision, 23(3):14.
  9. Devi, P., Kumar, P., & Bharadwaj, S. R. (2023). Computational analysis of retinal image quality with different contact lens designs in keratoconus.Contact Lens and Anterior Eye, 46(2):101794.
  10. Ampolu, N., Yarravarapu, D., Satgunam, P., Varadharajan, L. S., & Bharadwaj, S. R. (2022). Impact of induced pseudomyopia and refractive fluctuations of accommodative spasm on visual acuity.Clinical and Experimental Optometry, 14:1-7.
  11. Reena Durai, C. V., Hathibelagal, A., Rodriguez-Carmona, M., Barbur, J. L., & Bharadwaj, S. R. (2023). Effects of absolute monocular threshold on binocular summation of luminance flicker.PLoS One, 18(1):e0280785.
  12. Keel S, Lingham G, Misra N, Block S, Bourne R, Calonge M, Cheng CY, Friedman DS, Furtado JM, Khanna R, Mariotti S, Mathenge W, Matoto E, Müeller A, Rabiu M, Rasengane T, Resnikoff S, Wormald R, Yasmin S, Zhao J, Evans JR, Cieza A; Package of Eye Care Interventions Development Group.(2022). Toward Universal Eye Health Coverage-Key Outcomes of the World Health Organization Package of Eye Care Interventions: A Systematic Review. JAMA Ophthalmology. 140(12):1229-1238.
  13. Patel, A.M., Kumar, P., Vaddavalli, P. K., & Bharadwaj, S. R. (2022). Value of eccentric infrared photorefraction in evaluating keratoconus. Optometry and Vision Science, 99(10):763-773.
  14. Devi, P., Kumar, P., Marella, B., & Bharadwaj, S. R. (2022). Impact of degraded optics on monocular and binocular vision: Lessons from recent advances in highly-aberrated eyes. Seminars in Ophthalmology. Jul 2:1-18.
  15. Bandela, P. K., Bharadwaj, S. R. Ho, A., & Papas, E. (2022). The role of retinotopic cues in deciphering the direction and magnitude of dynamic monocular ocular accommodation: a review.Vision Research. 196:108026
  16. Sarkar, S., Devi, P., Vaddavalli, P., Reddy, J., & Bharadwaj, S. R.(2021). Differences in image quality following three keratorefractive procedures for myopia: Insights from a computational analysis. Optometry and Vision Science, In Press.
  17. Bharadwaj, S. R.,Ravisankar, C., Roy, S., & Satgunam, P. (2021). Fluctuations of steady-state accommodation is a marker for screening spasm of near reflex. Translational Vision Science and Technology. 10(11):9.
  18. Venkataramanan, K., Gawde, S., Hathibelagal, A.,Bharadwaj, S. R.(2021). Binocular fusion enhances the efficiency of spot-the-difference gameplay. PLoS One. 16(7): e0254715.
  19. Reena Durai, C. V., Rajendran, S.S., Webster, M. A., Vempati, S., &Bharadwaj, S. R.(2021). The magnitude of monocular light attenuation required to elicit the Pulfrich illusion.Vision Research. 187: 85 – 93 (Cover illustration).
  20. Roy, S., Bharadwaj, S. R.,Patil-Chhablani, P., & Satgunam, P. (2021). Spasm of near reflex: a comprehensive management protocol, treatment outcomes and classification. Journal of the American Association for Pediatric Ophthalmology and Strabismus (JAAPOS). S1091-8531(21)00142-7.
  21. Hathibelagal, A. R., Bharadwaj, S. R., Jalali, S., Subramanian, A., & Barbur, J. L. (2021). Evaluation of photoreceptor function in inherited retinal diseases using rod- and cone-enhanced flicker stimuli.Ophthalmic Physiological Optics, 41(4):874-884.
  22. Rani, P. K., Peguda, H. K., Chandrasekhar, M., Swarna, S., Jonnadula, G. B., James, J., Shinde, L., & Bharadwaj, S. R. 2021). Capacity building for diabetic retinopathy screening by optometrists in India: Model description and pilot results. Indian Journal of Ophthalmology, 69: 655 – 659.
  23. Marella, B., Conway, M., Suttle, C., & Bharadwaj, S. R. (2021). Contrast rivalry paradigm reveals suppression of monocular input in keratoconus. Investigative Ophthalmology & Visual Science 62(2):12.
  24. Padhy, T., Bharadwaj, S. R. Nayak, S., Rath, S., & Das, T. P. (2021). Accuracy and repeatability of refractive errors estimated using autorefractors with different measurement principles.Translational Vision Science and Technology. 10(1): 2.
  25. Kumar, P., Bandela, P. K. & Bharadwaj, S. R.,(2020). Do visual performance and optical quality vary across different contact lens correction modalities in keratoconus?Contact Lens and Anterior Eye. 43: 568 – 576.
  26. Bharadwaj, S. R., Roy, S., & Satgunam, P. (2020). Spasm of near reflex: Objective assessment of the near-triad.Investigative Ophthalmology & Visual Science. 61(8):18.
  27. Hathibelagal, A. R., Bharadwaj, S. R.Yadav, A. R., Subramanian, A., Sadler, J., & Barbur, J. L. (2020). Age-related change in flicker thresholds with rod- and cone-enhanced stimuli. PLoS One. 15(7):e0232784.
  28. Sarkar, S., Bharadwaj, S.R. Reddy, J., & Vaddavalli, P (2020). Optical Quality and Visual Performance after ReLEx SMILE, LASIK or PRK Refractive Surgery for Myopia. Optometry and Vision Science. 97: 360 – 369.
  29. Senthil, S., Deshmukh, S., Turaga, K., Pesala,V., Bandela,P. K., Ganesh, J., Garudadri, G. C., &Bharadwaj, S. R., (2020). Surgically induced Astigmatism and refractive outcomes after Phacotrabeculectomy.Indian Journal of Ophthalmology. 68(4):609-614.
  30. Nilagiri, V. K., Metlapally, S., Schor, C. M., & Bharadwaj, S. R.(2020). A computational analysis of retinal image quality in eyes with keratoconus. Scientific Reports.10(1):1321-1333.
  31. Metlapally, S., Bharadwaj, S.R. Roorda, A., Nilagiri, V. K., Yu, T. T., & Schor, C. M. (2019). Binocular cross-correlation analyses of the effects of high-order aberrations on the stereoacuity of eyes with keratoconus. Journal of Vision, 19(6):1 - 20.
  32. Ntodie, M.,Bharadwaj, S. R., Balaji, S., & Little, J- A. (2019). Comparison of 3 Gaze Position Calibration Techniques in 1st Purkinje-Image Based Eye Trackers. Optometry and Vision Science.96(8):587-598.
  33. Bharadwaj, S. R. Bandela, P. K., & Nilagiri, V. K. (2018). Lens magnification affects the estimates of refractive error obtained using eccentric infrared photorefraction. Journal of Optical Society of America A. 35:908-915.
  34. Nilagiri, V. K., Metlapally, S., Kalaiselvan, P., Schor, C. M., & Bharadwaj, S.R. (2018). LogMAR and stereo acuity in keratoconus corrected with spectacles and RGP contact lenses. Optometry and Vision Science 95(4):391-398.
  35. Sravani, G. &Bharadwaj, S. R., (2017). Focusing responses of the one eyed child. Optometry & Vision Science. 94(2):150-158.
  36. Ravikumar, S., Bradley, A., Bharadwaj, S. R.& Thibos, L. N. (2016). Expanding binocular depth of focus by combining monovision with diffractive bifocal intraocular lenses. Journal of Cataract and Refractive Surgery.42: 1288 - 1296.
  37. Sarkar, S., Bharadwaj, S.R. Reddy, J., & Vaddavalli, P (2020). Optical Quality and Visual Performance after ReLEx SMILE, LASIK or PRK Refractive Surgery for Myopia. Optometry and Vision Science. 97: 360 – 369.
  38. Bandela, P., Satgunam, P., Garg, P., &Bharadwaj, S. R., (2016). Corneal transplantation in disease affecting only one eye – does it make a difference to habitual binocular viewing?PLOS One. 11(3): e0150118.
  39. Sarkar, S., Vaddavalli, P. K., & Bharadwaj, S. R.(2016). Image quality analysis of the human visual system after LASER refractive surgery. PLOS One.11(2): e0148085.
  40. Thite, N., Jaggernath, J., Chinanayi, F., Bharadwaj, S.R.& Kunjeer, G. (2015). Pattern of optometry practice and range of services in India. Optometry & Vision Science. 92(5): 615 - 622.
  41. Sravani, G., Nilagiri, V. K., & Bharadwaj, S. R. (2015). Photorefraction estimates of refractive power varies with the ethnic origin of human eyes.Scientific Reports. 5(7976): 1 - 8.
  42. Veerendranath, P., Garg, P., & Bharadwaj, S. R.(2014). Binocular vision of bilaterally pseudophakic eyes with induced astigmatism. Optometry & Vision Science.91(9): 1118 - 1128.
  43. Jagini, K. K., Vaidyanath, H., & Bharadwaj, S.R.(2014). Utility of theoretical Hirschberg ratio for gaze position calibration. Optometry & Vision Science. 91(7): 778 - 785.
  44. Veerendranath, P., Garg, P., & Bharadwaj, S. R. (2014). Image quality analysis of pseudophakic eyes with uncorrected astigmatism.Optometry & Vision Science. 91(4): 444 - 451.
  45. Bharadwaj, S. R.Malavita, M., & Jayaraj, J. (2014). A psychophysical technique for estimating the accuracy and precision of retinoscopy. Clinical and Experimental Optometry.97(2): 164 – 170.
  46. Bharadwaj, S.R. Sravani, G., Little, J-A., Narasaiah, A., Wong, V., Woodburn, R., & Candy, T.R. (2013). Empirical variability in the calibration of slope-based eccentric photorefraction. Journal of Optical Society of America A. 30(5): 923 - 931.
  47. Singh. A., Veerendranath, P., Garg, P., & Bharadwaj, S. R.(2013). Relation between uncorrected astigmatism and visual acuity in pseudophakia. Optometry & Vision Science.90(4):378 - 384.
  48. Sarkar, S., Ali, M.J., & Bharadwaj, S.R. (2012). Revisiting the impact of Phenylephrine Hydrochloride on static and dynamic accommodation. Indian Journal of Ophthalmology. 60(1): 503 - 509.