Vivek Suganthan R

Scopus Publications

Evaluation of visual acuity and Vernier acuity with simulated water-induced blur in swimmers and non-swimmers
Vivek Suganthan Ramasubramanian, Aiswaryah Radhakrishnan
Sport Sciences for Health, 2026
Effect of Chromostereoscopic Stimulus on Accommodative Response and Subjective Perception
Vivek Suganthan Ramasubramanian, Kartheyaeni Jothi Madhavan, Shahid afridi Hyder Ali, Johan raj Jeyaraj, Swetha Selvakumar
British and Irish Orthoptic Journal, 2026
Purpose: The phenomenon of chromostereopsis, where colours are perceived at different depths due to the eye's optics, creates a potential conflict during accommodation. This prospective, cross-sectional study aimed to investigate the effect of different chromostereoscopic stimuli on the objective accommodative response and subjective user comfort. Methods: Thirty young, healthy adults (mean age 19.83 ± 1.18 years) read text passages presented on an iPad at a 50 cm viewing distance. Stimuli included red, green, blue, yellow, and mixed-colour text on a black background, compared to a standard black-on-white baseline. Accommodative lag was measured objectively using an open-field autorefractor, while subjective ratings of perceived depth and screen readability were collected via questionnaire. Results: A significant main effect of stimulus colour on accommodative lag was found (p < .001). The short-wavelength (blue) stimulus induced the greatest mean accommodative lag (0.61 D). Conversely, the long-wavelength (red) stimulus produced the smallest lag (0.18 D), indicating the most accurate accommodative focus. Subjective data strongly corroborated these findings, with blue being perceived as most distant and most difficult to read (76.67% and 73.33% of participants, respectively), while red was perceived as closest and yellow was perceived as the easiest to read (53.33%). Conclusion: Colour is a critical factor in visual ergonomics for dark-themed interfaces. A pure blue stimulus on a black background acts as a poor driver for accommodation, leading to significant focusing errors and a diminished perceptual experience. These findings provide a physiological basis for user interface design guidelines, suggesting that the use of short-wavelength, saturated text for reading tasks should be avoided to optimize visual comfort and performance.
Comparison of Vernier Acuity Measured with Three Different Water-induced Blur Simulation Methods
Vivek Suganthan Ramasubramanian, Aiswaryah Radhakrishnan
Journal of Ophthalmic and Vision Research, 2025
Purpose: Human vision is subnormal in an aquatic environment, and studies have used different methods to measure visual functions with water-induced blur (WIB). In this study, we compared vernier acuity measured using three different WIB simulation methods. Methods: Sixty young adults (20 in each group) with best-corrected visual acuity of ≥6/6 participated in the study. Three different methods, one for each study group, were used to simulate WIB in order to measure the vernier acuity. The methods comprised M1: a glass tank filled with water containing a wave motor to produce waves, M2: a sprinkler with uncontrolled water splash against the glass, and M3: a sprinkler with controlled water splash against the glass. For each of the three methods, vernier acuity was measured binocularly (three trials of 50 presentations each) both at baseline (without simulated WIB) in the absence of WIB and under simulated WIB. This was conducted using FrACT presented on the Display++ monitor at a distance of 2 meters from the participant. The vernier target consisted of two vertical lines (1 x 15 arcmin) with a vertical separation of 0.5 arcmin. Results: The mean baseline vernier acuity (arcsec) was found to be similar (F [2, 57] = 0.20, P = 0.82) among all three groups (M1: 13.28 ± 5.84, M2: 14.44 ± 6.34, M3: 14.05 ± 3.28). Vernier acuity with simulated WIB was least degraded with M1 (19.84 ± 8.40) and more degraded with M2 (288.74 ± 56.61), followed by M3 (49.14 ± 20.13). One-way ANOVA revealed a significant difference among the three methods (F [2, 57] = 354.72, P < 0.001). Conclusion: Our results suggest that the impact of simulated WIB on vernier acuity is not comparable due to differences in the strength of blur and the varied spatial and temporal properties of different simulated WIB methods. This emphasizes the need to develop a blur metric specific to WIB to objectively quantify its effect on different visual functions.
Low-vision intervention for oculocutaneous albinism in a Tertiary Eye Care Hospital in India
Rajiv Raman, Sarika Gopalakrishnan, Kalpa Negiloni, RVivek Suganthan, Saranya Velu
Saudi Journal of Ophthalmology, 2023
PURPOSE: The objective of this study on patients with albinism in different age groups was to compare their level of visual impairment with the low-vision intervention (LVI) and its benefit. METHODS: The medical records of 72 patients with low vision secondary to albinism who were referred to the low vision care clinic from 2015 to 2017 were analyzed. This included the demographic profile such as age, gender, occupation, ocular history, visual acuity status, and type of low-vision device (LVD) preferred. The LVDs prescribed and its subsequent improvement was compared. RESULTS: In this data, 70 (97.2%) people had oculocutaneous albinism and 2 (2.8%) had ocular albinism. Majority of the patients had hyperopic astigmatism 42 (58.3%) and with-the-rule astigmatism 58 (93.5%). Presenting mean visual acuity for distance was noted to be 0.88 logMAR which improved to 0.83 logMAR with the help of spectacle correction. The most commonly prescribed LVD was a dome magnifier for 15 (34.9%) patients. In all the patients, there was statistically significant improvement (P < 0.05) in near vision with the help of LVDs. CONCLUSION: The study highlights the importance of appropriate LVI for each subdivided age group. Patients with albinism who have received medical and surgical treatment have no or a limited role in restoring useful vision.
Challenges and impact of COVID-19 lockdown on Indian optometry practice: A survey-based study
Siddharth K Karthikeyan, Pooja Nandagopal, Vivek Suganthan R, Anush Nayak
Journal of Optometry, 2022
PURPOSE: The Indian government announced a nationwide lockdown as a preventive measure to control the prevailing COVID-19 pandemic. This survey was developed and conducted to assess the impact of lockdown on Indian optometry practice. METHODS: A survey questionnaire was designed and circulated across the optometrists practicing in India through multiple social media platforms. All the data were extracted and only valid response were analyzed and reported. RESULTS: A total of 691 optometrists participated in the survey. Most of the participants (22.25%) were in private practice followed by academics (14.89%). Among the valid responses collected, it was found that 43.37% of the respondents were consulting patients during the lockdown. Of these, 27.17% of optometrists were examining infectious cases and 48.68% were examining all the patients who came for consultation. Approximately 50.94% of the participated optometrist had begun telephonic/e‑mail/video consultations. In addition, 64.48% reported that optometrists were at an equal risk of clinching COVID‑19 on comparison with other domains during patient examination. Nearly 30.44% respondents felt that optometrists would face challenges in approaching the patient post COVID-19 considering the close working distance. CONCLUSION: A proportion of optometrist have switched to some form of teleconsultation in order to aid patients during this prevailing pandemic. Regulatory bodies should issue appropriate guidelines regarding the safe optometry practice for the betterment of both patient and practitioners during face-to-face consultation.
Finite Element Analysis of Cornea and Lid Wiper during Blink, with and without Contact Lens
Vivek Suganthan Ramasubramanian, S. Meenatchi Sundaram, Rinu Thomas, S. Ve. Ramesh, B. Raghuvir Pai, Manali Hazarika, Shah Mohammed Abdul Khader, Rakshath G. Poojary, H. Girish, Vernon Seth Crasto
Journal of Ophthalmology, 2022
Ocular surface disorders such as Lid Wiper Epitheliopathy (LWE), Superior Epithelial Arcuate Lesion (SEAL), and contact lens-induced Limbal Stem Cell Deficiency (LSCD) as well as Superior Limbic Keratoconjunctivitis (SLK) affect one’s quality of life. Hence, it is imperative to investigate the underlying causes of these ocular surface disorders. During blink, the undersurface of the eyelid tends to interact with the cornea and the conjunctiva. The presence of a contact lens can add to the biomechanical frictional changes on these surfaces. To estimate these changes with and without a contact lens, a finite element model (FEM) of the eyelid wiper, eyeball, and contact lens was developed using COMSOL Multiphysics. Biomechanical properties such as von Mises stress (VMS) and displacement were calculated. Our study concluded that (a) maximum VMS was observed in the lid wiper in the absence of contact lens in the eye and (b) maximum VMS was observed in the superior 1.3 mm of the cornea in the presence of the contact lens in the eye. Thus, the development of friction-induced ocular surface disorders such as LWE, SLK, SEAL, and LSCD could be attributed to increased VMS. FEA is a useful simulation tool that helps us to understand the effect of blink on a normal eye with and without CL.
Finite element analysis of the human eye for a range of intraocular pressure
R. Vivek Suganthan, S. Meenatchi Sundaram, S. Ve Ramesh, Thomas Rinu, R. Pai, Shah Mohammed Abdul Khader, Manali Hazarika, H. Girish
Lecture Notes in Electrical Engineering, 2020

Vivek Suganthan R

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Scopus Publications