Major abdominal operations place considerable physiological demands on the patient. The effects of prolonged anaesthesia, changes in blood pressure, fluid redistribution, blood loss and alterations in oxygenation may influence different organ systems during the perioperative period. Preoperative evaluation therefore focuses mainly on the patient's general medical condition and fitness for surgery. In comparison, ocular examination is not routinely included, even though some patients may have pre-existing visual or ocular abnormalities that become apparent or more noticeable after surgery. Visual symptoms after non-ophthalmic surgery are uncommon, but they can be distressing for both patients and treating physicians. Blurring of vision, difficulty in focusing, diplopia, eye discomfort, watering, photophobia and a perceived reduction in vision are among the complaints that may be encountered during the postoperative period. In many patients, these symptoms are temporary and may be related to ocular surface dryness, corneal exposure, refractive error or the effects of anaesthesia.¹-³ Nevertheless, persistent or marked visual deterioration should not be considered a routine consequence of surgery, as it may occasionally indicate a significant ocular or neurological disorder. The ocular surface is particularly susceptible during general anaesthesia. Reduction in spontaneous blinking and incomplete closure of the eyelids can expose the cornea and interfere with its normal protective mechanisms. This may result in corneal epithelial damage or exposure keratopathy, leading to pain, foreign-body sensation, photophobia, excessive tearing and temporary blurring of vision.⁴,⁵ Proper protection of the eyes during anaesthesia is therefore an important component of perioperative care. Although uncommon, serious visual complications have also been described following major non-ocular operations. Perioperative visual loss may result from conditions such as ischemic optic neuropathy, retinal vascular occlusion or cortical visual impairment.⁶-⁸ Prolonged operative time, considerable blood loss, hypotension, anemia and disturbances in ocular perfusion have been reported as possible contributing factors, particularly in patients undergoing lengthy procedures. Another important consideration is the presence of ocular disease before surgery. Cataract, glaucoma, diabetic retinopathy, age-related macular changes and uncorrected refractive errors may remain undetected in patients who have not undergone a recent eye examination.⁹,¹⁰ If the baseline visual status is not documented, it may be difficult to determine whether a visual complaint after surgery represents a new postoperative problem or an abnormality that was already present. Several systemic diseases frequently encountered in surgical patients also have ocular consequences. Diabetes mellitus can cause progressive retinal vascular damage and diabetic retinopathy, while long-standing hypertension may produce retinal vascular and optic nerve changes.¹¹,¹² Identification of such abnormalities before surgery may help in appropriate patient counselling and timely referral for ophthalmological management. Recording the patient's ocular status before surgery is therefore useful not only for identifying previously undiagnosed disease but also for providing a baseline for postoperative comparison. Assessment of visual acuity, refractive status and the anterior segment, together with measurement of intraocular pressure and fundus examination when indicated, can provide clinically relevant information. Patients with significant ocular or systemic risk factors may subsequently be monitored more carefully during the postoperative period. Despite the possible importance of these issues, relatively little attention is given to ocular assessment in patients undergoing major abdominal surgery. In particular, there is a need for prospective evaluation of the relationship between pre-existing ocular findings, perioperative events and postoperative visual complaints. The present study was therefore planned as a collaborative study between the Departments of General Surgery and Ophthalmology. It aims to document the preoperative ocular status of patients undergoing major abdominal surgery, determine the frequency and nature of postoperative visual complaints, and evaluate the possible association of these complaints with patient-related and perioperative factors.

Study Design and Setting This prospective observational study was conducted in the Department of General Surgery, Venkateshwara Institute of Medical Sciences (VIMS), Gajraula, Uttar Pradesh, India, in collaboration with the Department of Ophthalmology. The study was conducted from 2025 to 2026 and included patients undergoing major abdominal surgery. Ethical approval was obtained from the Institutional Ethics Committee before initiation of the study, and written informed consent was obtained from all participants. Study Participants A total of 155 consecutive patients aged 18 years or older who were admitted to the Department of General Surgery and scheduled for major abdominal surgery were enrolled. Patients undergoing major gastrointestinal, hepatobiliary, pancreatic, colorectal or other intra-abdominal procedures were considered eligible. Patients were included if they were willing to participate and could undergo both preoperative and postoperative ocular assessment. Patients with severe pre-existing visual impairment that prevented reliable assessment, acute ocular infection or trauma, recent major ophthalmic surgery, known neurological disease associated with significant visual impairment, or inability to communicate visual symptoms adequately were excluded. Preoperative Assessment Baseline demographic and clinical information was recorded using a structured study proforma. The information included age, sex, presenting diagnosis, indication for surgery, type of abdominal procedure, elective or emergency status, relevant systemic comorbidities, previous ocular history, spectacle use and any pre-existing visual complaints. All participants underwent a preoperative ophthalmological examination in collaboration with the Department of Ophthalmology. Unaided and best-corrected visual acuity was recorded separately for each eye using a Snellen visual acuity chart. Refraction was performed when indicated. External ocular examination and slit-lamp biomicroscopy were carried out to assess the ocular surface, cornea, anterior chamber, iris and lens. Intraocular pressure was measured using standard tonometry. Dilated fundus examination was performed when clinically indicated to assess the optic disc, macula and retina. Any ocular abnormality detected before surgery was documented as a baseline finding. Perioperative Assessment Perioperative information was obtained from the patient's operative and anaesthesia records. The recorded parameters included the type and duration of surgery, type and duration of anaesthesia, intraoperative patient position, estimated blood loss, requirement for blood transfusion, episodes of hypotension, oxygen desaturation, lowest recorded oxygen saturation, use of vasopressors and significant intraoperative complications. Postoperative Assessment Patients were evaluated postoperatively for any new visual symptoms. Assessment was performed within 24 hours after surgery, at 48–72 hours, and before discharge. Patients were specifically questioned regarding blurred vision, difficulty focusing, reduction in visual acuity, diplopia, photophobia, ocular pain, foreign-body sensation, dryness, burning and excessive watering. For each visual complaint, the time of onset, duration, laterality, severity and progression were recorded. Patients with new, persistent or clinically significant visual symptoms underwent detailed ophthalmological examination. This included assessment of visual acuity, slit-lamp examination, intraocular pressure measurement and fundus examination, as clinically indicated. Postoperative findings were compared with the preoperative baseline examination to determine whether the complaint represented a new ocular change. Statistical Analysis Data were entered into Microsoft Excel and analysed using IBM SPSS Statistics version 26.0. Continuous variables were expressed as mean ± standard deviation or median with interquartile range, depending on the distribution of the data. Categorical variables were expressed as frequencies and percentages. Continuous variables were compared using the independent t-test or Mann–Whitney U test, as appropriate, while categorical variables were analysed using the Chi-square test or Fisher's exact test. Preoperative and postoperative visual acuity were compared using an appropriate paired test. Logistic regression analysis was performed to identify factors independently associated with postoperative visual complaints where appropriate. A two-sided p-value <0.05 was considered statistically significant.

A total of 155 patients undergoing major abdominal surgery were included in the present study. The mean age of the study population was 52.6 ± 13.8 years, with patients ranging from 20 to 78 years. The largest proportion of participants belonged to the 51–60-year age group (25.2%), followed by those aged 41–50 years (24.5%) and those aged >60 years (21.3%). There was a male predominance, with 91 (58.7%) males and 64 (41.3%) females. Diabetes mellitus was present in 31 (20.0%) patients, while hypertension was reported in 38 (24.5%) patients. Other systemic comorbidities were present in 21 (13.5%) patients (Table 1). Table 1. Demographic and Clinical Characteristics of Study Participants Variable n % 18–30 years 18 11.6 31–40 years 27 17.4 41–50 years 38 24.5 51–60 years 39 25.2 >60 years 33 21.3 Male 91 58.7 Female 64 41.3 Diabetes mellitus 31 20.0 Hypertension 38 24.5 Other comorbidities 21 13.5 With respect to the surgical profile, gastrointestinal procedures constituted the largest group, accounting for 62 (40.0%) cases, followed by hepatobiliary procedures in 36 (23.2%) and colorectal procedures in 28 (18.1%) patients. Hernia and abdominal wall procedures accounted for 17 (11.0%) cases, while 12 (7.7%) underwent other major abdominal procedures. The majority of surgeries were elective (119; 76.8%), whereas 36 (23.2%) were emergency procedures. Surgery lasted more than 3 hours in 50 (32.3%) patients. Intraoperative hypotension was documented in 32 (20.6%) patients, significant blood loss in 28 (18.1%), oxygen desaturation in 19 (12.3%), and blood transfusion was required in 24 (15.5%) patients (Table 2). Table 2. Surgical and Perioperative Characteristics Characteristic n % Gastrointestinal surgery 62 40.0 Hepatobiliary surgery 36 23.2 Colorectal surgery 28 18.1 Hernia/abdominal wall surgery 17 11.0 Other major abdominal surgery 12 7.7 Elective surgery 119 76.8 Emergency surgery 36 23.2 Surgery ≤3 hours 105 67.7 Surgery >3 hours 50 32.3 Intraoperative hypotension 32 20.6 Significant blood loss 28 18.1 Oxygen desaturation 19 12.3 Blood transfusion 24 15.5 Preoperative ophthalmological examination showed that 103 (66.5%) patients had no significant ocular abnormality, whereas 52 (33.5%) had at least one pre-existing ocular abnormality. Refractive error was the most commonly identified finding, affecting 27 (17.4%) patients. Cataract was observed in 15 (9.7%) patients, while ocular surface abnormalities were present in 7 (4.5%). Raised intraocular pressure or glaucoma was detected in 3 (1.9%) patients. These findings highlight the presence of previously existing ocular conditions among a substantial proportion of patients undergoing major abdominal surgery (Table 3). Table 3. Preoperative Ocular Findings Ocular finding n % Normal ocular examination 103 66.5 Refractive error 27 17.4 Cataract 15 9.7 Ocular surface abnormality 7 4.5 Raised IOP/glaucoma 3 1.9 Any ocular abnormality 52 33.5 During postoperative assessment, 29 (18.7%) patients reported at least one new visual complaint, while 126 (81.3%) remained free of visual symptoms. Blurred vision was the most frequent complaint, occurring in 16 (10.3%) patients, followed by difficulty focusing in 8 (5.2%). Dryness or burning and foreign-body sensation were each reported by 7 (4.5%) patients. Ocular pain was reported by 4 (2.6%), diplopia by 3 (1.9%), and photophobia by 2 (1.3%) patients. Since some patients experienced more than one symptom, the individual percentages were not mutually exclusive. Among the 29 symptomatic patients, ophthalmological examination demonstrated ocular surface dryness or exposure-related changes in 11 (37.9%), refractive causes in 6 (20.7%), and cataract-related findings in 4 (13.8%). Other ocular abnormalities were identified in 3 (10.3%), whereas 5 (17.2%) had no significant abnormality on examination. Most symptoms were transient and improved during follow-up (Table 4). Table 4. Postoperative Visual Complaints and Ophthalmological Findings Finding n % Postoperative visual complaints (N=155) No visual complaint 126 81.3 Any visual complaint 29 18.7 Blurred vision 16 10.3 Difficulty focusing 8 5.2 Dryness/burning 7 4.5 Foreign-body sensation 7 4.5 Ocular pain 4 2.6 Diplopia 3 1.9 Photophobia 2 1.3 Ophthalmological findings among symptomatic patients (n=29) Ocular surface dryness/exposure changes 11 37.9 Refractive cause 6 20.7 Cataract-related finding 4 13.8 Other ocular abnormality 3 10.3 No significant abnormality 5 17.2 Analysis of perioperative risk factors showed that postoperative visual complaints were significantly more common among patients undergoing prolonged surgery. Among patients whose surgery lasted >3 hours, 14 (28.0%) developed postoperative visual complaints compared with 15 (14.3%) among those whose surgery lasted ≤3 hours (p=0.041). Similarly, patients who experienced intraoperative hypotension had a significantly higher frequency of visual complaints than those without hypotension (31.3% vs. 15.4%; p=0.048). Although postoperative visual complaints were more frequent among patients with diabetes mellitus (29.0%) than among those without diabetes (16.1%), the difference was not statistically significant (p=0.087). Likewise, hypertension, significant blood loss and oxygen desaturation were not significantly associated with postoperative visual complaints (Table 5). Table 5. Association of Clinical and Perioperative Factors with Postoperative Visual Complaints Factor Visual complaint present n (%) Visual complaint absent n (%) p-value Age >60 years 10 (30.3) 23 (69.7) 0.071 Age ≤60 years 19 (15.6) 103 (84.4) Diabetes mellitus 9 (29.0) 22 (71.0) 0.087 No diabetes mellitus 20 (16.1) 104 (83.9) Hypertension 10 (26.3) 28 (73.7) 0.198 No hypertension 19 (16.2) 98 (83.8) Surgery >3 hours 14 (28.0) 36 (72.0) 0.041 Surgery ≤3 hours 15 (14.3) 90 (85.7) Intraoperative hypotension 10 (31.3) 22 (68.7) 0.048 No hypotension 19 (15.4) 104 (84.6) Significant blood loss 7 (25.0) 21 (75.0) 0.218 No significant blood loss 22 (17.3) 105 (82.7) Oxygen desaturation 6 (31.6) 13 (68.4) 0.112 No oxygen desaturation 23 (16.9) 113 (83.1) Overall, the study demonstrated that one-third of patients had pre-existing ocular abnormalities before major abdominal surgery, while approximately one-fifth developed postoperative visual complaints. Blurred vision was the predominant postoperative symptom. Most complaints were transient, whereas prolonged surgery and intraoperative hypotension showed statistically significant associations with postoperative visual symptoms

The present study evaluated preoperative ocular status and postoperative visual complaints among 155 patients undergoing major abdominal surgery at a tertiary care centre. In our study, 33.5% of patients had one or more pre-existing ocular abnormalities, while 18.7% developed postoperative visual complaints. Blurred vision was the most frequent postoperative symptom. Prolonged operative duration and intraoperative hypotension were significantly associated with postoperative visual complaints. In the present study, refractive error was the most common preoperative ocular abnormality (17.4%), followed by cataract (9.7%) and ocular surface abnormalities (4.5%). The presence of these conditions before surgery emphasizes the importance of documenting baseline visual status. Uncorrected refractive error and age-related cataract are important contributors to visual impairment worldwide, and their presence may complicate the assessment of new visual symptoms after surgery. Flaxman et al. reported that uncorrected refractive error and cataract remain among the major causes of visual impairment globally.9 Similarly, Bourne et al. highlighted cataract and refractive error as important causes of vision loss worldwide.10 Postoperative visual complaints were reported by 29 (18.7%) patients in our study. Blurred vision (10.3%) was the most frequently reported symptom, followed by difficulty focusing, ocular dryness and foreign-body sensation. Most symptoms were mild and transient. These findings are clinically plausible because perioperative factors can temporarily affect the ocular surface and visual function. Yu et al. reported perioperative ocular injuries following non-ocular surgery, with corneal injury being an important postoperative ocular problem.³ Similarly, Segal et al. emphasized that perioperative corneal abrasions may present with pain, foreign-body sensation, photophobia, tearing and blurred vision.⁴ The relatively high frequency of transient visual complaints in the present study may partly be explained by ocular surface disturbance during general anaesthesia. General anaesthesia reduces spontaneous blinking and may result in incomplete eyelid closure, thereby increasing corneal exposure. Cucchiara and Black demonstrated that corneal injury can occur during general anaesthesia, particularly when normal protective mechanisms of the eye are impaired.⁵ Thus, appropriate eye protection during anaesthesia remains an important preventive measure. An important finding of the present study was the association between prolonged surgery and postoperative visual complaints. Patients undergoing surgery for more than 3 hours had a significantly higher frequency of visual symptoms than those undergoing shorter procedures (28.0% vs. 14.3%; p=0.041). Longer procedures may expose patients to prolonged anaesthesia, reduced blinking, ocular surface exposure, fluid shifts and greater hemodynamic disturbance. Roth and Moss noted that duration and complexity of surgery are among the factors considered in the evaluation of perioperative visual loss, particularly in prolonged procedures.⁶ Intraoperative hypotension was also significantly associated with postoperative visual complaints in our study. Visual symptoms occurred in 31.3% of patients who experienced hypotension compared with 15.4% of those without hypotension (p=0.048). Reduction in systemic blood pressure may compromise ocular perfusion, particularly in patients with pre-existing vascular or ocular disease. Although severe perioperative visual loss is rare, ischemic optic neuropathy and other ischemic ocular disorders have been associated with disturbances in perfusion during major surgery. Lee et al. reported the importance of perioperative factors in cases of postoperative visual loss, particularly in patients undergoing prolonged major surgery.⁷ Roth also emphasized the role of systemic hypotension, blood loss and impaired ocular perfusion in perioperative visual loss.⁸ In our study, diabetes mellitus was associated with a higher proportion of postoperative visual complaints, although the difference was not statistically significant (29.0% vs. 16.1%; p=0.087). Diabetes is relevant because chronic hyperglycemia can produce retinal microvascular damage and diabetic retinopathy. Cheung et al. described diabetic retinopathy as a major microvascular complication of diabetes and an important cause of visual impairment.⁹ The absence of statistical significance in our study may be related to the relatively small number of diabetic patients and the low frequency of clinically important postoperative ocular events. Hypertension was also more common among patients with postoperative visual complaints, although the association was not statistically significant. Chronic hypertension can produce retinal vascular changes and may contribute to ocular vascular disease. Wong and Mitchell described a spectrum of retinal and optic nerve changes associated with hypertension.¹⁰ The presence of hypertension may therefore be relevant when assessing patients at risk of ocular complications, even though no statistically significant relationship was demonstrated in the present study. The majority of postoperative symptoms in our study were related to ocular surface disturbance, and no patient developed permanent severe visual loss. This finding is consistent with the fact that serious perioperative visual loss is uncommon, whereas minor ocular surface symptoms may occur more frequently. Roth et al. emphasized that perioperative visual loss represents a rare but potentially devastating complication and that prevention requires recognition of modifiable perioperative risk factors.¹¹ The present study also demonstrates the practical value of collaboration between the Departments of General Surgery and Ophthalmology. A preoperative ocular examination provides a baseline visual status and can identify previously undiagnosed conditions such as refractive error, cataract, glaucoma or ocular surface disease. When postoperative visual complaints occur, comparison with the preoperative findings allows clinicians to distinguish pre-existing abnormalities from potentially new postoperative changes. This may facilitate early referral and appropriate management. The findings should, however, be interpreted in light of certain limitations. The study was conducted at a single tertiary-care centre and included a relatively limited number of patients. The frequency of serious postoperative visual complications may be too low to establish definitive risk factors. In addition, some visual complaints were subjective and could be influenced by postoperative fatigue, medications or the patient's general condition. Longer follow-up and multicentre studies involving larger populations would provide further information regarding the incidence and determinants of postoperative ocular complications.

The present study indicates that pre-existing ocular abnormalities are relatively common among patients undergoing major abdominal surgery and that postoperative visual complaints, although generally transient, are not uncommon. Blurred vision was the predominant symptom. Prolonged surgery and intraoperative hypotension were significantly associated with postoperative visual complaints. These findings support the value of documenting baseline ocular status before major surgery and maintaining appropriate perioperative eye protection. Collaboration between General Surgery and Ophthalmology may facilitate early identification of ocular risk factors and timely evaluation of patients who develop postoperative visual symptoms.

1. Roth S. Perioperative visual loss: what do we know, what can we do? Br J Anaesth. 2009;103 Suppl 1:i31-i40. 2. Lee LA. Postoperative visual loss and anesthetic management. Curr Opin Anaesthesiol. 2013;26(3):375-381. 3. Yu HD, Chou AH, Yang MW, Chang CJ. An analysis of perioperative eye injuries after nonocular surgery. Acta Anaesthesiol Taiwan. 2010;48(4):168-171. 4. Segal KL, Fleischut PM, Kim C, Levine B, Faggiani SL, Banach DB, et al. Evaluation and treatment of perioperative corneal abrasions. J Ophthalmol. 2014;2014:901767. 5. Cucchiara RF, Black S. Corneal injury during general anesthesia. Anesth Analg. 1988;67(10):911-914. 6. Roth S, Moss HE. Update on perioperative visual loss: what do we know, what can we do? Br J Anaesth. 2018;120(6):e147-e158. 7. Postoperative Visual Loss Study Group. Risk factors associated with ischemic optic neuropathy after spinal fusion surgery. Anesthesiology. 2012;116(1):15-24. 8. Lee LA, Roth S, Posner KL, Cheney FW, Caplan RA, Newman NJ, et al. The American Society of Anesthesiologists postoperative visual loss registry: analysis of 93 spine surgery cases with bilateral and unilateral visual loss. Anesthesiology. 2006;105(4):652-659. 9. Flaxman SR, Bourne RRA, Resnikoff S, Ackland P, Braithwaite T, Cicinelli MV, et al. Global causes of blindness and distance vision impairment 1990–2020: a systematic review and meta-analysis. Lancet Glob Health. 2017;5(12):e1221-e1234. 10. Bourne RRA, Stevens GA, White RA, Smith JL, Flaxman SR, Price H, et al. Causes of vision loss worldwide, 1990–2010: a systematic analysis. Lancet Glob Health. 2013;1(6):e339-e349. 11. Cheung N, Mitchell P, Wong TY. Diabetic retinopathy. Lancet. 2010;376(9735):124-136. 12. Wong TY, Mitchell P. Hypertensive retinopathy. N Engl J Med. 2004;351(22):2310-2317.