European Journal of Cardiovascular Medicine

Cataract remains the leading cause of reversible blindness worldwide, accounting for approximately 51% of global blindness, with a higher burden in low- and middle-income countries.¹ Small incision cataract surgery (SICS) is extensively performed due to its cost-effectiveness, shorter learning curve, and excellent visual outcomes comparable to phacoemulsification.²

Anesthesia is a crucial determinant of surgical success in cataract surgery. Traditional regional anesthesia techniques such as retrobulbar and peribulbar blocks provide good analgesia and akinesia but are associated with complications like globe perforation, retrobulbar hemorrhage, optic nerve damage, and systemic toxicity.³,⁴

Subconjunctival anesthesia using lignocaine provides localized analgesia by blocking terminal nerve endings and avoids the risks associated with deep orbital injections.⁵ However, it may be associated with conjunctival chemosis and subconjunctival hemorrhage.

Topical anesthesia using paracaine, supplemented with intracameral lignocaine, has gained popularity as a needle-free technique. It improves patient acceptance, reduces injection-related anxiety, and allows faster postoperative recovery.⁶,⁷ Intracameral lignocaine enhances analgesia during intraocular manipulation.

Despite increasing use of these techniques, limited comparative data exist regarding their efficacy in SICS, which involves more manipulation than phacoemulsification. The present study aims to compare these two anesthesia modalities in terms of intraoperative pain, surgeon comfort, safety, and visual outcomes

Study Design and Setting

This prospective, randomized, comparative clinical study was conducted in the Department of Ophthalmology of a tertiary care teaching hospital over a period of 12 months. The study adhered to the principles of the Declaration of Helsinki. Institutional Ethics Committee approval was obtained prior to commencement of the study, and written informed consent was taken from all participants.

Sample Size and Study Population

A total of 120 patients diagnosed with uncomplicated senile cataract and scheduled for elective small incision cataract surgery (SICS) were enrolled in the study. The sample size was calculated based on previous studies comparing pain scores under different anesthesia techniques, assuming a power of 80% and a confidence level of 95%.

Inclusion Criteria

• Patients aged 40 years and above
• Diagnosed with uncomplicated senile cataract
• Patients planned for manual SICS with posterior chamber intraocular lens implantation
• Cooperative patients able to follow instructions during surgery

Exclusion Criteria

• Traumatic or complicated cataract
• Pseudoexfoliation syndrome
• Subluxated lens
• History of uveitis or glaucoma
• Previous ocular surgery in the study eye
• Known hypersensitivity to lignocaine or paracaine
• Patients with hearing impairment or cognitive dysfunction affecting pain assessment

Randomization and Allocation

Patients were randomly allocated into two equal groups (n = 60 each) using a computer-generated random number table. Allocation concealment was ensured using sealed opaque envelopes opened immediately before surgery.

• Group A: Subconjunctival lignocaine anesthesia
• Group B: Topical paracaine with intracameral lignocaine anesthesia

Preoperative Assessment

All patients underwent a comprehensive preoperative ophthalmic evaluation including:

• Best corrected visual acuity (BCVA)
• Slit-lamp biomicroscopy
• Intraocular pressure measurement using applanation tonometry
• Fundus examination (direct or indirect ophthalmoscopy)
• Keratometry and A-scan biometry for intraocular lens power calculation
• Routine systemic evaluation and anesthetic fitness
•  

Anesthesia Protocol

Group A: Subconjunctival Lignocaine Anesthesia

• One drop of topical paracaine 0.5% was instilled prior to injection.
• 0.5–1.0 ml of 2% lignocaine was injected subconjunctivally in the superior bulbar conjunctiva using a 26-gauge needle.
• Gentle digital pressure was applied for uniform diffusion of the anesthetic agent.
• Adequate anesthesia was confirmed before commencement of surgery.

Group B: Topical Paracaine with Intracameral Lignocaine

• Topical paracaine 0.5% eye drops were instilled three times at 5-minute intervals prior to surgery.
• During surgery, 0.5 ml of preservative-free 1% lignocaine was injected slowly into the anterior chamber after completion of capsulorhexis.
• Care was taken to avoid sudden rise in intraocular pressure during intracameral injection.

Surgical Technique

All surgeries were performed using a standardized manual SICS technique by a single experienced surgeon to eliminate inter-surgeon variability. A superior fornix-based conjunctival flap was created. A self-sealing scleral tunnel incision was fashioned. Continuous curvilinear capsulorhexis was performed. Hydrodissection and nucleus delivery were carried out using the viscoexpression technique. Cortical cleanup was completed using a Simcoe cannula. A posterior chamber polymethyl methacrylate (PMMA) intraocular lens was implanted in the capsular bag. The wound was checked for integrity, and conjunctiva repositioned without sutures.

Intraoperative Assessment

• Pain assessment: Intraoperative pain was evaluated immediately after surgery using the Visual Analog Scale (VAS) ranging from 0 (no pain) to 10 (worst pain imaginable).
• Surgeon comfort: Assessed subjectively by the operating surgeon and graded as poor, fair, or good based on patient cooperation and ocular stability.
• Need for supplemental anesthesia: Documented if additional topical drops or intracameral lignocaine were required.

Postoperative Evaluation

Patients were examined on postoperative day 1 for:

• Visual acuity
• Anterior segment reaction
• Corneal edema
• Wound integrity
• Intraocular pressure

Any postoperative complications were documented and managed accordingly.

Outcome Measures

Primary outcome:

• Intraoperative pain score (VAS)

Secondary outcomes:

• Surgeon comfort
• Requirement for supplemental anesthesia
• Intraoperative and postoperative complications
• Early postoperative visual outcome

Statistical Analysis:

Data were entered into Microsoft Excel and analyzed using SPSS software (version 26.0). Continuous variables were expressed as mean ± standard deviation and analyzed using Student’s t-test. Categorical variables were expressed as frequency and percentage and analyzed using the Chi-square test. A p-value < 0.05 was considered statistically significant.

A total of 120 patients undergoing small incision cataract surgery were included in the final analysis, with 60 patients in each group. Patient recruitment, allocation, follow-up, and analysis are shown in the CONSORT flow diagram (Figure 1).

Both groups were statistically comparable with respect to age, gender, laterality, and preoperative visual acuity (p > 0.05), ensuring homogeneity of study populations.(Table1) Patients in Group A experienced significantly lower intraoperative pain compared to Group B, demonstrating superior analgesic efficacy of subconjunctival lignocaine.(Table2) Surgeon comfort was significantly better in the subconjunctival lignocaine group, likely due to reduced patient movement and better pain control.(Table 3) Patients receiving topical–intracameral anesthesia required supplemental anesthesia more frequently, indicating comparatively less consistent analgesia.(Table 4) While minor anesthesia-related side effects differed between groups, no serious intraoperative or postoperative complications were observed in either group.(Table 5) Early postoperative visual outcomes were comparable between both anesthesia techniques.(Table6)

Figure 1: CONSORT flow diagram showing enrollment, randomization, allocation, follow-up, and analysis of patients undergoing small incision cataract surgery under subconjunctival lignocaine anesthesia (Group A) and topical paracaine with intracameral lignocaine anesthesia (Group B).

Assessed for eligibility (n = 138)

│

├─ Excluded (n = 18)

│   ├─ Not meeting inclusion criteria (n = 10)

│   │   ├─ Complicated cataract (n = 6)

│   │   ├─ Pseudoexfoliation / glaucoma (n = 4)

│   ├─ Declined to participate (n = 5)

│   └─ Other reasons (n = 3)

│

└─ Enrolled and randomized (n = 120)

    │

    ├─ Allocated to Group A: Subconjunctival lignocaine (n = 60)

    │   ├─ Received allocated intervention (n = 60)

    │   └─ Did not receive allocated intervention (n = 0)

    │

    └─ Allocated to Group B: Topical paracaine +

        intracameral lignocaine (n = 60)

        ├─ Received allocated intervention (n = 60)

        └─ Did not receive allocated intervention (n = 0)

Follow-Up

│

├─ Group A

│   ├─ Lost to follow-up (n = 0)

│   └─ Discontinued intervention (n = 0)

│

└─ Group B

    ├─ Lost to follow-up (n = 0)

    └─ Discontinued intervention (n = 0)

Analysis

│

├─ Group A analyzed (n = 60)

│   └─ Excluded from analysis (n = 0)

│

└─ Group B analyzed (n = 60)

    └─ Excluded from analysis (n = 0)

Table 1: Demographic and Preoperative Characteristics of Study Participants

Table 2: Intraoperative Pain Assessment (VAS Score)

*Statistically significant

Table 3: Surgeon Comfort Assessment

*Statistically significant

Table 4: Requirement of Supplemental Anesthesia

*Statistically significant

Table 5: Intraoperative and Postoperative Complications

*Statistically significant

Table 6: Postoperative Visual Outcome (Day 1)

The choice of anesthesia for small incision cataract surgery (SICS) is a crucial determinant of patient comfort, surgical ease, and overall outcomes. With the shift away from traditional regional blocks due to their potential complications, less invasive anesthesia techniques such as subconjunctival and topical–intracameral anesthesia have gained prominence.³,⁴ The present study compared these two techniques and demonstrated that subconjunctival lignocaine provided superior intraoperative analgesia and surgeon comfort, while topical paracaine with intracameral lignocaine offered a safe, needle-free alternative with comparable visual outcomes.

In our study, intraoperative pain scores were significantly lower in patients receiving subconjunctival lignocaine anesthesia. This finding can be explained by the effective blockade of terminal sensory nerve endings supplying the conjunctiva and sclera, which are extensively manipulated during SICS, particularly during scleral tunnel construction and nucleus delivery.⁵,⁸ Similar observations have been reported by Gupta et al., who found better pain control and patient cooperation with subconjunctival anesthesia compared to topical techniques.⁵

Topical anesthesia alone has been shown to be insufficient for procedures involving extensive ocular manipulation.⁶ To overcome this limitation, intracameral lignocaine has been used as an adjunct to topical anesthesia, providing additional analgesia by anesthetizing intraocular structures such as the iris and ciliary body.⁷ In the present study, although topical paracaine supplemented with intracameral lignocaine provided acceptable analgesia, patients experienced higher pain scores compared to the subconjunctival group, particularly during nucleus delivery. These findings are consistent with previous studies reporting increased discomfort during manual SICS under topical anesthesia.⁹

Surgeon comfort was significantly better in the subconjunctival group. Reduced patient movement, improved ocular stability, and lower pain perception contribute to better surgical conditions. This is particularly relevant in SICS, where controlled manipulation is essential to avoid complications such as iris prolapse and posterior capsular rupture. Kumar and Dowd highlighted that inadequate analgesia can lead to sudden patient movement, increasing the risk of intraoperative complications.³

The requirement for supplemental anesthesia was higher in the topical–intracameral group, further supporting the superior and more consistent analgesic effect of subconjunctival lignocaine. Similar findings were reported by Vichare and Ghosh, who observed a higher need for additional anesthesia in patients undergoing SICS under topical anesthesia.⁹

Regarding complications, subconjunctival anesthesia was associated with a higher incidence of mild conjunctival chemosis and subconjunctival hemorrhage. However, these were transient, self-limiting, and did not affect surgical outcomes. These findings are in agreement with earlier studies that have reported minor conjunctival complications with subconjunctival injections but emphasized their benign nature.⁵,¹⁰ On the other hand, patients in the topical–intracameral group more commonly experienced transient burning sensation, likely due to repeated instillation of topical anesthetic drops.⁶

Postoperative visual outcomes were comparable between the two groups, indicating that the choice of anesthesia did not influence early visual recovery. This observation aligns with previous studies demonstrating that anesthesia technique does not significantly affect visual outcomes when surgery is performed uneventfully.²,⁹ The faster postoperative recovery and absence of conjunctival chemosis in the topical–intracameral group may be advantageous in high-volume cataract surgery programs and outreach settings.

From a patient perspective, topical anesthesia with intracameral lignocaine offers the advantage of being needle-free, reducing anxiety and improving acceptance, especially among apprehensive patients.⁶ However, careful patient selection is essential, as uncooperative patients may not tolerate the relatively higher intraoperative discomfort associated with this technique.

Overall, the findings of this study suggest that subconjunctival lignocaine remains a reliable and effective anesthesia technique for SICS, particularly in cases requiring greater surgical manipulation. Topical paracaine with intracameral lignocaine is a viable alternative in selected patients, offering safety and patient convenience with acceptable analgesia.

Strengths of the Study

• Prospective randomized design
• Uniform surgical technique performed by a single surgeon
• Objective pain assessment using VAS

Limitations

• Single-center study
• Subjective nature of pain perception
• Short postoperative follow-up

Clinical Implication: Subconjunctival lignocaine remains a reliable and effective anesthesia technique for SICS in resource-limited settings, while topical–intracameral anesthesia can be safely adopted in appropriately selected patients to improve patient comfort and surgical efficiency

Subconjunctival anesthesia with lignocaine provides superior intraoperative analgesia, improved surgeon comfort, and a reduced need for supplemental anesthesia in patients undergoing small incision cataract surgery. It offers consistent and effective pain control during critical steps of the procedure, particularly scleral tunnel construction and nucleus delivery. Topical paracaine supplemented with intracameral lignocaine is a safe and effective needle-free alternative, providing acceptable analgesia with comparable early postoperative visual outcomes. This technique is associated with faster postoperative recovery and greater patient acceptance, especially in cooperative and low-risk cases.

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