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Year : 2022  |  Volume : 4  |  Issue : 1  |  Page : 24

A comparative evaluation of sub-Tenon's anesthesia versus peribulbar anesthesia in manual small-incision cataract surgery

Department of Ophthalmology, Narayan Medical College and Hospital, Nellore, Andhra Pradesh, India

Date of Submission24-Feb-2022
Date of Decision29-Mar-2022
Date of Acceptance29-Mar-2022
Date of Web Publication19-May-2022

Correspondence Address:
P Ramya Deepthi
Department of Ophthalmology, Narayana Medical College, Chinthareddypalem, Nellore, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/pajo.pajo_13_22

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Purpose: The purpose of this study is to compare analgesic, akinetic effects, and safety profile of sub-Tenon's and peribulbar anesthesia in manual small-incision cataract surgery (MSICS).
Materials and Methods: In a hospital-based randomized, comparative study, patients who fulfilled inclusion criteria and who have been posted for elective surgery for uncomplicated cataracts were randomized to receive either sub-Tenon's or peribulbar block. Pain during anesthesia and surgery, akinesia, lid movements during surgery, and complications after anesthesia were assessed.
Results: A total of 120 eyes of 120 patients were studied. Of which, 60 underwent sub-Tenon and another 60 had undergone peribulbar block. Pain during anesthesia was significantly less in sub-Tenon group (37/60, 61.6%) than peribulbar group (10/60, 16.6%), whereas pain during surgery was comparable in both groups, 40/60 (66.6%) in sub-Tenon group and 45/60 (75%) in peribulbar group. Peribulbar group has significantly Grade 0 akinesia (31/60, (51.7%) than 0% in sub-Tenon group. Mild complications such as chemosis 34/60 (56.7%) and subconjunctival hemorrhage (37/60, 61.7%) were more in sub-Tenon group than in the peribulbar group, 17/60 (28.3%) and 22/60 (36.7%), respectively.
Conclusion: This study has shown that sub-Tenon's anesthesia provides adequate analgesia and akinesia for cataract surgery with minimal and less severe complications. Therefore, sub-Tenon's anesthesia is a relatively safe method with lesser learning curve, effective, and alternate to peribulbar anesthesia for MSICS.

Keywords: Akinesia, manual small incision cataract surgery, peribulbar anesthesia, sub-Tenon's anesthesia

How to cite this article:
Deepthi P R, Amruth CK, Asritha B, Gowtami V. A comparative evaluation of sub-Tenon's anesthesia versus peribulbar anesthesia in manual small-incision cataract surgery. Pan Am J Ophthalmol 2022;4:24

How to cite this URL:
Deepthi P R, Amruth CK, Asritha B, Gowtami V. A comparative evaluation of sub-Tenon's anesthesia versus peribulbar anesthesia in manual small-incision cataract surgery. Pan Am J Ophthalmol [serial online] 2022 [cited 2023 Jun 3];4:24. Available from: https://www.thepajo.org/text.asp?2022/4/1/24/345493

  Introduction Top

Cataract is the leading cause of blindness in the world. In a developing country like India, where our progress is dependent mainly on the available workforce, blindness due to cataract poses a significant problem in terms of human morbidity, economic loss, and social burden.[1]

Cataract surgery is the most common surgical procedure in ophthalmology and is the most cost-effective of all surgical procedures. Cataract surgery has been reported to have a good safety profile.[2] For the masses, especially in a nation like ours, the manual small incision cataract surgery (MSICS) offers suture-less cataract surgery as a low-cost alternative to phacoemulsification with the added advantage of having broader applicability, safety, a more comfortable learning curve, and machine independence.[3]

In cataract surgeries, various anesthesia types were used in the past but were associated with many disadvantages and complications. Proper anesthetic management is an integral part of any successful eye surgery.[4] The traditional demand for total akinetic anesthesia decreased with advancements in cataract surgeries, while safety and analgesia are still the basic requirements.[5]

Retrobulbar anesthesia was earlier used for cataract extraction, due to rare but severe complications such as retrobulbar hemorrhage, globe perforation, optic nerve injury, ptosis, central retinal vein or artery occlusion, and brainstem anesthesia, many ophthalmologists had to replace retrobulbar anesthesia with peribulbar anesthesia.[6],[7]

However, peribulbar anesthesia does not eliminate serious complications, although these probably occur less frequently. The local anesthetic drug's spread is sometimes nonhomogenous and incomplete due to orbit's separated multicompartmental anatomy which may lead to imperfect blocks or the need for multiple injections or sometimes large injectable volumes.

Since multiple comorbidities and multiple drug use are very common in patients undergoing cataract surgery, researchers have focused on anesthetic techniques that ensure patients' comfort, safety, and compliance.

Sub-Tenon's anesthesia provided a quicker onset of anesthesia, better akinesia, consistency, effectiveness, and better patient compliance.[8] It avoids sharp needles passing into the orbit, but chemosis and subconjunctival hemorrhage (SCH) are frequent.[9] Ideally, an anesthetic technique must be completely safe, simple, easy, and cause maximum benefit with a minimum anesthetic agent and complications.[10]

This study is taken to compare the efficacy and complications encountered between sub-Tenon's anesthesia and peribulbar anesthesia in manual small-incision cataract surgery (MSICS).

  Materials And Methods Top

A hospital-based randomized comparative study was done on the selected patients who are admitted for cataract surgery in the department of ophthalmology at a tertiary care hospital in South India for a 6-month duration (July 2021–December 2021). This study has institutional ethics approved and strictly adhered to the principles of the Declaration of Helsinki. Written and informed consent was obtained from all the patients included in the study.

Inclusion criteria

Cataract cases posted for surgery with age >40 who agreed to informed consent.

Exclusion criteria

  1. Age –70 years
  2. Signs of chronic ocular inflammation – uveitis
  3. History of ocular trauma
  4. History of convulsion and epilepsy
  5. Sensitivity to xylocaine
  6. Clotting abnormalities
  7. Inability to give informed consent
  8. Inability to understand the visual analog pain scale.

During the period mentioned above, 120 randomly selected patients fulfilling the criteria were included in the study. They were randomly divided into two groups: Group A (n = 60) underwent MSICS under sub-Tenon's anesthesia and Group B (n = 60) patients underwent MSICS by peribulbar anesthesia. Efficacy and safety of two methods of anesthesia in MSICS concerning pain during the administration of anesthesia, intraoperative pain, akinesia, lid movements, and complications were compared.

Preoperative evaluation

All the patients in both the study groups underwent all routine preoperative ocular and systemic examinations. From all the patients, written and informed consent was obtained.

Procedure: sub-Tenon's anesthesia

The conjunctiva is anesthetized with the topical anesthetic solution (0.5% proparacaine). An eyelid speculum is inserted at this point to improve access. Throughout the procedure, the patient is asked to look up and outward to expose the inferonasal quadrant. A small tent of the conjunctiva is raised with a pair of nontoothed forceps approximately 8–10 mm from the limbus. A small nick was made in the tented conjunctiva with a pair of Westcott ophthalmic scissors. The closed scissors are introduced through the aperture created and a tunnel is fashioned through the bare sclera by blunt dissection through the Tenon's capsule. A curved blunt sub-Tenon's cannula (19 G, 25 mm) is then inserted with the syringe of anesthetic solution (2 ml of lignocaine with adrenaline 1:200,000 mixed with 1 ml of 0.5% bupivacaine and hyaluronidase 150 IU/ml) attached. The cannula is glided along the globe's contour and gentle contact of its tip is maintained with the sclera until the tip was past the posterior of the equator of the globe and 3 ml of local anesthetic was delivered slowly.

Peribulbar anesthesia

The eyelid and periocular areas were cleaned with 5% povidone iodine. To ensure that the eye was in the neutral position of gaze, the patient was instructed to look straight ahead. A 11/4 inch 23G sharp needle attached to a 5 ml syringe containing the anesthetic agent was inserted through the lid at the junction of the middle and outer third of the lower orbital rim, parallel to the floor of the orbit and tangential to the globe. After negative aspiration for blood, 3 ml of lignocaine 2% mixed with adrenaline 1:200,000, hyaluronidase 150 IU/ml, and 2 ml of 0.5% bupivacaine were injected. A supplementary injection of 2 ml was given at the supraorbital notch with a needle directed toward the orbital roof. The eye was massaged digitally for 5–10 min.

Assessment of pain

The patients were asked to grade the pain they felt on a linear scale of 0–4 (no pain = Grade 0, mild pain = Grade 1, moderate pain = Grade 2, severe pain = Grade 3, and maximum pain imaginable = Grade 4). Patients were asked to grade separately for pain during the administration of anesthesia and pain during surgery.

Grading of intraoperative akinesia

Akinesia was noted and graded based on ocular movements:

Grading of lid movements during surgery:

Grading of chemosis:

Grading of subconjunctival hemorrhage:

Analysis of results

This study compares the efficacy of sub-Tenon's anesthesia and peribulbar anesthesia concerning pain during the administration of anesthesia, intraoperative pain, akinesia, lid movements, and complications such as SCH and chemosis in MSICS.

Statistical methods

IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. To test the association between the groups, Chi-square test was used. Any P < 0.05 is considered statistically significant. To test the mean difference between the two groups, Students's t-test was used.

  Results Top

Chi-square test shows that there is a significant difference between both the groups with regard to pain on the administration of the anesthesia for Grades 0 and 1 (Chi-square value = 26.795, P < 0.001) [Table 1].
Table 1: Pain during anesthesia

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  • Seventy-five percent of patients had no pain in peribulbar group (Chi-square value = 1.101) compared to 66.6% of patients in the sub-Tenon group [Table 2]
  • About 51.7% of peribulbar patients had Grade 0 akinesia and it is statistically significant (Chi-square value = 49.237, P < 0.001) as compared with 0% in sub-Tenon group [Table 3]
  • About 88.3% of the peribulbar group of patients had Grade 0 little or no lid squeezing and it is statistically significant (Chi-square value = 6.92, value = 0.0313) compared with 66.7% in the sub-Tenon group [Table 4]
  • About 56.7% of patients in the sub-Tenon group had chemos and it is statistically significant (Chi-square value = 10.090, P = 0.0182) when compared to 28.3% of the peribulbar group of patients [Table 5]
  • About 61.7% in the sub-Tenon group had SCH and it is statistically significant (Chi-square value = 8.152, P = 0.0432) compared to 36.7% of the peribulbar group [Table 6].
Table 2: Pain during surgery

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Table 3: Ocular movement during surgery

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Table 4: Intraoperative lid movements

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Table 5: Chemosis after administration of anesthesia

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Table 6: Subconjunctival hemorrhage after administration of anesthesia

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  Discussion Top

Different local anesthetic techniques are available for performing cataract surgery. An ideal anesthetic technique should be safe from serious complications and should be effective in terms of providing good analgesia and akinesia.[10]

Topical anesthesia is free of complications, but it lacks akinesia. Needle blocks, such as peri- and retrobulbar anesthesia, provide excellent analgesia and akinesia but are associated with serious and life-threatening complications.[11]

Sub-Tenon's technique was first introduced by Turnbull and later revisited by Hansen. and by Stevens in the early 1990s has recently become popular.[12] It is also known as parabulbar block, medial episcleral block, and pinpoint anesthesia. It provides effective anesthesia and akinesia and is safe, effective, with less serious complications when compared to needle blocks.[9]

In the present study, pain during the administration of anesthesia, intraoperative pain, akinesia, lid movements and complications encountered in sub-Tenon's anesthesia and peribulbar anesthesia in MSICS were compared.

Pain during anesthesia was dramatically lower in the sub-Tenon group of patients (61.6% had Grade 0 pain) than in the peribulbar group (16.6%), but intraoperative pain was comparable in both the groups, 75% in peribulbar group and 66.6% in sub-Tenon group. There have been similar reports in the studies done by Datta et al.,[7] Parkar et al.,[13] Samuel et al.,[14] Azmon et al.,[15] and Briggs et al.[16]

Peribulbar anesthesia had the upper hand in terms of intraoperative akinesia when compared with sub-Tenon's anesthesia (51.7% Grade 0 akinesia in peribulbar and 0% in sub-Tenon group),[13] this is in correlation with the results of studies done by Samuel et al.[14] and Parkar et al. Some studies such as Ripart et al.[6] reported that sub-Tenon's block provided a better globe akinesia than peribulbar anesthesia. Ashok et al.,[8] Azmon et al.,[15] and Budd et al.[17] reported that sub-Tenon's block was comparable to peribulbar block in providing adequate globe akinesia. Intraoperative lid movements were slightly more in the sub-Tenon group of patients (33.3% with lid movements) than the peribulbar group (11.7% with lid movements).

The incidence of chemosis was slightly higher in sub-Tenon group (56.7%) than peribulbar group (28.3%) and this may be due to closeness of sub-Tenon's space to subconjunctival space and can be due to faulty technique. Subconjunctival hemorrhage was more in the sub-Tenon group (61.7%) as compared with patients in the peribulbar group (36.7%) supported by Budd et al.,[17] Parkar et al.[13] and Iganga et al.[18] Subconjunctival hemorrhage is due to damage of subconjunctival vessels during dissection into sub-Tenon's space. Larger bleeds may be caused by damage to vortex veins in the posterior sub-Tenon's space, mainly if a rigid cannula is used.[12]

Sub-Tenon's anesthesia was more comfortable for the patient during the time of administration and intraoperatively, it provided good analgesia and adequate akinesia without the complications of a sharp needle injection. Complications such as retrobulbar hemorrhage, optic nerve injury, and globe perforation are least with this technique; however, caution is needed in patients with the compromised sclera.[13]

Sub-Tenon's anesthesia has added benefits of immediate analgesia, minimal requirement of anesthetic volume, no raise in intraocular pressure, and no need for globe compression.[19] Sub-Tenon's anesthesia has been advocated primarily for cataract surgery but is also effective for trabeculectomy, squint surgery, and vitreoretinal surgery. This technique is highly favored in patients who are on anticoagulants, antiplatelets, and nonsteroidal anti-inflammatory drugs.

Sub-Tenon's block has its limitations such as SCH and chemosis which are common.[12] Incomplete akinesia rarely causes intraoperative difficulties but is generally acceptable to surgeons. Because of poor akinesia sub-Tenon anesthesia is not suitable for patients who are unable to cooperate and for surgeries necessitating a wide opened eye-like keratoplasty.

In a country like India dealing with low-income people, MSICS offers an attractive low-cost, high-volume alternative. In peribulbar technique, large volumes of anesthetic drug have to be given extraconally, and the time for anesthetic effect is more when compared to sub-Tenon's anesthesia. Surgery was started immediately after the administration of anesthesia in the sub-Tenon group. The amount of anesthetic agents used in sub-Tenon's anesthesia is also less. Hence, in a larger hospital or a community eye care setting, it is more economical and less time-consuming.

  Conclusion Top

Sub-tenon's technique is a relatively safest method of administering anesthesia without the complications of a sharp needle injection. The patient was more comfortable during the time of administration and also intraoperatively has good analgesia and akinesia. Hence, it can be recommended as a relatively safe with lesser learning curve, effective, and alternative to peribulbar anesthesia for small-incision cataract surgery.


We would like to acknowledge Rajesh Kumar Darfi, statistician in our College for his contribution to this article.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Vajpayee RB, Joshi S, Saxena R, Gupta SK. Epidemiology of cataract in India: Combating plans and strategies. Ophthalmic Res 1999;31:86-92.  Back to cited text no. 1
Gogate P, Deshpande M, Nirmalan PK. Why do phacoemulsification? Manual small-incision cataract surgery is almost as effective, but less expensive. Ophthalmology 2007;114:965-8.  Back to cited text no. 2
Singh K, Misbah A, Saluja P, Singh AK. Review of manual small-incision cataract surgery. Indian J Ophthalmol 2017;65:1281-8.  Back to cited text no. 3
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Deshpande S, Deshpande SS, Reddy R, Reddy V. Comparing the effectiveness and safety of sub-tenon's anesthesia and peribulbar anesthesia in anterior segment surgery. Indian J Clin Exp Ophthalmol 2016;2:201-6.  Back to cited text no. 4
Jayashree MP, Anandi VK, Hiremath S, Dasar LV. A comparative study of sub- tenons anaesthesia versus peribulbar anaesthesia- In manual small incision cataract surgery. Indian J Clin Exp Ophthalmol 2019;5:246-51.  Back to cited text no. 5
Ripart J, Lefrant JY, de La Coussaye JE, Prat-Pradal D, Vivien B, Eledjam JJ. Peribulbar versus retrobulbar anesthesia for ophthalmic surgery: An anatomical comparison of extraconal and intraconal injections. Anesthesiology 2001;94:56-62.  Back to cited text no. 6
Datta, Abhijit, K. A. Ghosh, Sayan Basu, Kali Shankar Das, and Subhro Ghosal. “Exploring the anaesthetic options for manual small incision cataract surgery (MSICS): A comparative evaluation of peribulbar, sub-tenon's and topical anaesthesia.” (2008): 82-83.  Back to cited text no. 7
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Guise P. Sub-Tenon's anesthesia: An update. Local Reg Anesth 2012;5:35-46.  Back to cited text no. 12
Parkar T, Gogate P, Deshpande M, Adenwala A, Maske A, Verappa K. Comparison of subtenon anaesthesia with peribulbar anaesthesia for manual small incision cataract surgery. Indian J Ophthalmol 2005;53:255-9.  Back to cited text no. 13
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Matcha SC, Nandyala SK, Murahari VK. Comparison of sub tenon'sv/s peribulbar anesthesia in manual small incision cataract surgery cases. MRIMS Journal of Health Sciences. 2015 Jan 1;3(1):68.  Back to cited text no. 14
Azmon B, Alster Y, Lazar M, Geyer O. Effectiveness of sub-Tenon's versus peribulbar anesthesia in extracapsular cataract surgery. J Cataract Refract Surg 1999;25:1646-50.  Back to cited text no. 15
Briggs MC, Beck SA, Esakowitz L. Sub-Tenon's versus peribulbar anaesthesia for cataract surgery. Eye (Lond) 1997;11:639-43.  Back to cited text no. 16
Budd JM, Brown JP, Thomas J, Hardwick M, McDonald P, Barber K. A comparison of sub-Tenon's with peribulbar anaesthesia in patients undergoing sequential bilateral cataract surgery. Anaesthesia 2009;64:19-22.  Back to cited text no. 17
Iganga ON, Fasina O, Bekibele CO, Ajayi BG, Ogundipe AO. Comparison of peribulbar with posterior sub-tenon's anesthesia in cataract surgery among Nigerians. Middle East Afr J Ophthalmol 2016;23:195-200.  Back to cited text no. 18
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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


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