Impact of caffeine intake on ocular physiology | Scientific Program 2026

Sri Devaraj Urs Medical College, India

Title: Impact of caffeine intake on ocular physiology

Abstract:

Introduction:

Caffeine is a substance that people use in a variety of forms and in varying amounts in their daily life all around the world. Caffeine has wide variations in its nature of action on biological tissues.
Accommodation is the ability of Eye’s to adjust its focus on objects at varying distances, plays a vital role in visual acuity and overall eye function. This process involves the contraction or relaxation of the ciliary muscles, altering the shape of the eye's crystalline lens as it adapts to objects at various distances. Pupillary response and accommodation are important physiological processes of the eye that affect vision. Pupil dilation is regulated by the autonomic nervous system, its a dynamic response to changes in ambient light, influencing the amount of light entering the eye and subsequently affecting visual perception.
Intraocular Pressure (IOP) refers to the pressure exerted by the fluid (aqueous humor), with a normal range typically falling between 10 to 21 mmHg. The regulation of IOP is primarily governed by the equilibrium between the production and drainage of aqueous humor.

Material and Methods: This cross-sectional study aimed to investigate the health-related characteristics of 88 healthy young individuals (44 with Coffee consumption and 44 without consumption of Coffee) from SDUAHER, Kolar. Ethical considerations include obtaining informed consent, and the study has received approval from an ethics committee.

INCLUSION CRITERIA:
- Healthy participants of both Gender specifically aged 19 to 30 years,
- Refractive correction of spherical equivalent ≤ ±0.50D, and achieving a best spectacle-corrected visual acuity of 6/6 or better
- IOP less than 21mmHg
EXCLUSION CRITERIA:
- History of ocular surgery
- Systemic/Ocular diseases
- Accommodative anomalies and Pupillary defects
- Regular smokers

Subjects are experimentally grouped as Group A are participants with Coffee intake & group B without coffee intake.

For participants in Group A, 50ml of coffee (1.2g of caffeine in 50ml milk) and Group B are participants without coffee. A thorough ocular examination was be conducted, including patient history, visual acuity testing, slit lamp examination, and fundus examination.

Following a standardized 20-minute interval and 40-minute post-coffee consumption,

Monocular amplitude of accommodation utilized the Royal Air Force (RAF) Ruler, with subjects wearing spectacles at a 15 mm vertex distance and focusing on a movable target at 40 cm.
Pupil size, measured in a dimly lit room using a ruler, involved recording the horizontal diameter in cm, which was then converted to millimeters.
Intraocular pressure (IOP) was assessed with a Non Contact Tonometer.

Results:

Table 1 : Comparison of Gender, Age & PD in Participants Consuming Coffee and without Coffee

	Without Coffee	With Coffee
Female	23 (0.52 %)	22 (50 %)
Male	21 (0.48 %)	22 (50 %)
Age	23.52 ± 1.12	23.70 ± 1.19
PD(mm)	62.25 ± 1.33	62.20 ± 1.39

Table 2 : Comparison of IOP, pupil size and accommodation in both subjects with and without Coffee consumption

Ocular Parameters		Baseline		20 min Interval		40 min Interval
Ocular Parameters		OD	OS	OD	OS	OD	OS
Amplitude of Accommodation (D)	With Coffee	7.898 ± 0.539	7.864 ± 0.431	8.023 ± 0.336	8 ± 0.369	7.966 ± 0.445	7.886 ± 0.425
	P value			0.044	0.012	0.118	0.661
	Without Coffee	7.57 ± 0.86	7.54 ± 0.82
Pupil Size (mm)	With Coffee	5.714+0.502	5.703+0.433	5.95 ± 0.38	5.753 ±0.389	5.707 ±0.471	5.713 ±0.404
	P value			0.001	0.274	0.579	0.902
	Without Coffee	5.62 ± 0.25	5.69 ± 0.28
IOP (mm Hg)	With Coffee	15.3 ±1.29	14.66±1.31	15.64±1.11	14.84±3.3	14.93±1.99	14.25±1.23
	P value			0.090	0.721	0.122	0.49
	Without Coffee	14.86 ± 1.36	13.86 ± 1.85

Conclusion: Our findings suggest that caffeine may temporarily enhance accommodation and pupil size without substantially impacting IOP.

Biography:

Dr. Chaitra M C is a highly experienced medical professional currently serving as a Professor in the Department of Ophthalmology at Sri Devaraj Urs Medical College, Kolar. With 14 years of teaching experience, she is deeply committed to mentoring undergraduate, postgraduate, and Allied Health Sciences students. Her core areas of interest include cataracts, uvea, ocular trauma, medical education, medical ethics, and research. She completed her M.B.B.S. at Kempegowda Institute of Medical Sciences, Bangalore, and her M.S. in Ophthalmology at M V J Medical College & Research Center, Bangalore, both affiliated with RGUHS University. During her master's program, she authored a thesis titled "A clinical study of dacryocystitis". To complement her clinical knowledge, she pursued Post Graduate Diplomas in Medico Legal Systems (PGDMLS) and Quality Management of Hospital and Healthcare Organizations (PGDQMHHO) from SSODL, Pune. Additionally, she completed a Masterclass in Clinical Ophthalmology approved by The Royal College of Ophthalmologists in 2021 and underwent advanced training in Medical Education Technologies at the NMC nodal Centre, CMC Vellore.

Clinically, Dr. Chaitra is highly skilled in general ophthalmology and ophthalmic surgeries. She is competent in performing Small Incision Cataract Surgery (SICS) and proficiently manages complications while training post-graduate students. Her surgical repertoire also includes oculoplasty, dacryocystectomy, therapeutic keratoplasty, and retinal laser procedures for diabetic patients. At her institution, she is actively in charge of Retinopathy of Prematurity screening and treatment. Beyond her clinical and teaching duties, Dr. Chaitra holds significant leadership and administrative responsibilities. She has been a postgraduate guide for M.S. Ophthalmology and M. Optometry students for three years and served as the Department Registrar for over six years until December 2024. She currently acts as the Convenor of the Scientific Review Board, a task force member for NAAC's 7th criteria, a core member of the Learning Management System, and a member of the Board of Studies for Allied Health Sciences. Externally, she extends her expertise as an external board member of the Research Advisory Committee at Apollo University and has guided an MBA student from Mysuru University. An avid researcher, Dr. Chaitra has published 51 scientific papers in indexed journals and holds an H-index of 4. She has actively participated in and presented oral papers and posters at numerous state, national, and international conferences. Her research portfolio includes multiple funded and non-funded multidisciplinary projects.

In recognition of her exceptional contributions to the field, Dr. Chaitra was honoured with the Distinguished Researcher Award in Ophthalmology in January 2026 by the International Scientific Laurels Committee. Furthermore, she was awarded the prestigious Honorary Membership of the National Academy of Medical Sciences (MNAMS) at the 65th convocation held at PGIMER, Chandigarh, in November 2025. She is registered with the Karnataka Medical Council and maintains active affiliations with the Karnataka Ophthalmic Society, All India Ophthalmic Society, Women Ophthalmologists Society, and is a life member of the Epidemiology Foundation of India.