Manual small incision cataract (MSICS) surgery has emerged as a preferred technique in the management of cataracts, especially in a rural set up and in cases of grade 3 – 4 nuclear cataracts.[1,2] This surgery is performed through a 6.0mm – 6.5mm self-sealing sclera -corneal tunnel incision either in the superior or temporal portions of the sclera.[3] The incision is mostly left un-sutured in the event of a good apposition of the sclero-corneal tunnel. In the immediate post-operative period a significant proportion of the patients develop symptoms of dry eyes the etiology of which may be multifactorial.[4] Although age may be a factor, derangements in the performance of the lacrimal functional unit have also shown to be responsible.[5,6] The symptoms of dry eyes seemed to improve with time. In this narrative review we have attempted to provide an insight into the various etiological factors of the dry eyes occurring after cataract surgery.

An extensive electronic literature search was done using search engines like PubMed and Google scholar using the mesh terms/ key words “Pathogenesis, post-operative dry eyes, manual small incision cataract surgery”. The database revealed 77 articles out of which 34 were relevant for our study.

One of the main mechanisms discussed in studies by Cho et al, Kohlhaas et al, Sutu et al, Venugopal et al was cutting of the corneal nerves due to the surgical incision.[7,8,9,10] Cornea has a rich nerve supply which is vital for its structural and functional integrity. The entry into the anterior chamber made during the small incision cataract surgery causes direct cutting of these nerve fibers thereby causing a reduced corneal sensation. This further disturbs the lacrimal functional unit feedback which in turn causes reduction in flow of tears and blink rate. This will lead to tear film instability. A previously published study concluded that dry eye symptoms are more likely in early post-operative period in cases where grooved incision are performed.[7] Neurogenic inflammation also might be one of the cause for reduced corneal sensitivity. Studies done by Mao Kusano, Atsushi Kawahara, Jong Soo Lee, Xue-Min Li, Kensaku Miyake, Nathan G. Congdon mentioned that prolonged use of topical medications as eye drops postoperatively can cause dry eyes de-novo or worsen the clinical features in patients with preexisting dry eyes.[11,12,13,14,15,16] Topical steroids and NSAIDs (non steroidal anti inflammatory drug) were the main culprits in this category. Donghyun Jee and Veronica Pianini further highlighted the role of preservatives present in eye drops.[17,18] The preservatives in corticosteroids, NSAIDS and antibiotic eye drops are toxic to the corneal epithelium and delay the healing process of the ocular surface. BAK or benzalkonium chloride is the most often implicated in this toxicity.[19] Some post operative medications like Moxifloxacin eye drops are available as preservative free.[20] However all other post-operative medications have preservatives, mainly BAK. Tear film after cataract surgery was discussed in Studies done by Anubhav Baveja, Jayshree MP, Kensaku Miyake, Asadolah Movahedan, Yuli Park, Ratna Sitompul.[21,22,15,23,24,25] Miyake et al. Studied the effect of diquafosol sodium (DQS) on the ocular surface in operated eyes after cataract surgery . Patients undergoing cataract surgery were evaluated using subjective symptom score, tear breakup time (TBUT), fluorescein staining of corneal and conjunctival and Schirmer I test preoperatively and 4 weeks after surgery.[15] It was concluded that cataract surgery causes tear film instability and DQS can be useful in treating these patients.[26] Meibomian gland dysfunction as a causative factor for post operative dry eye was highlighted by authors A.J. Bron, Kyung Eun Han, Yuli Park, Christine Sutu in their respective studies.[27,28,24,9] In addition to this Meibum quality scores and lid margin abnormalities were also evaluated in the study by Yuli Park.[24] A significant correlation was found between ocular symptom scores, inflammatory cytokine concentration and MGD parameters with dry eyes after cataract surgery. Jin Sun Kim et al. reported in their study about the lipid layer thickness changes of the tear film after cataract surgery. LipiView interferometer was used to do Lipid Layer Thickness (LLT) measurements. They concluded that there was a significant reduction in Lipid Layer Thickness at one month post operative period.[29] Reduction in goblet cell density as a causative factor for dry eyes was highlighted in studies done by Kensaku Miyake, Christine Sutu, Taehoon Oh.[15,9,30] A strong correlation between the loss of goblet cells and mean operative time was demonstrated in the study by Taehoon Oh.[30] Topical Diclofenac use was found to be responsible for reduction in goblet cells in comparison with the other commonly used topical NSAIDs.[15] Soon-Phaik Chee, Christine Sutu in their respective studies discussed surgical trauma and trauma due to inflammation to the ocular surface as a causative factor.[31,9] This was most often encountered in patients with complicated cataracts and those with pseudoexfoliation.[32] Intra operative exposure to the operating scope light for prolonged periods was studied and discussed as an important causative factor for post-operative dry eye.[33,34] This was most often encountered in surgeries by novice manual small incision surgeons who generally took a longer time to complete the surgery. Thus, as per the various studies done in this regard, the aetiology behind the development of dry eyes following manual small incision cataract surgery is multifactorial. The following table lists the mechanisms as suggested by various authors: Table 1: SN Author details Mechanism / Pathogenic factors 1 Cho et al Kohlhaas et al Sutu et al Venugopal et al Cutting of nerve endings due to surgical incision 2 Baveja et al Jayshree et al Miyake et al Movahedan et al Park et al Sitompul et al Tear film instability after surgery 3 Kim et al Thinning of lipid layer following surgery 4 Kusano et al Kawahara et al Lee et al Li et al Miyake et al Congdon et al Long term use of topical medication 5 Jee et al Pianini et al Presence of preservatives in eye drops 6 Miyake et al Oh et al Sutu et al Decrease goblet cell density after cataract surgery 7 Chee et al Sutu et al Surgical trauma and trauma due to inflammation to the ocular surface 8 Bron et al Han et al Park et al Sutu et al Meibomian gland dysfunction 9 Cho et al Ipek et al Operating microscope light

Clinically significant dry eye symptomatology was common after manual small incision cataract surgery. There are myriad factors involved in its occurrence of which, transection of corneal nerves during surgery, tear film instability and the use of post-operative topical medication with preservatives rank as the most important causes. A reduction in surgical incision size during MSICS by performing back cuts, using preservative free topical medications in the post-operative period and shortening the duration of the surgical procedure are some of the recommendations we would like to suggest to reduce incidence of post-operative dry eye symptoms.

1. Gogate P, Deshpande M, Nirmalan PK. Why do phacoemulsification? Manual small-incision cataract surgery is almost as effective, but less expensive. Ophthalmology. 2007 May 1;114(5):965-8. 2. Devendra J, Agarwal S, Singh PK. A comparative study of clear corneal phacoemulsification with rigid IOL versus SICS; the preferred surgical technique in low socio-economic group patients of rural areas. Journal of clinical and diagnostic research: JCDR. 2014 Nov;8(11):VC01. 3. Jauhari N, Chopra D, Chaurasia RK, Agarwal A. Comparison of surgically induced astigmatism in various incisions in manual small incision cataract surgery. International journal of ophthalmology. 2014;7(6):1001. 4. Kasetsuwan N, Satitpitakul V, Changul T, Jariyakosol S. Incidence and pattern of dry eye after cataract surgery. PloS one. 2013;8(11). 5. Moss SE, Klein R, Klein BE. Incidence of dry eye in an older population. Investigative Ophthalmology & Visual Science. 2003 May 1;44(13):810-. 6. Stern ME, Gao J, Siemasko KF, Beuerman RW, Pflugfelder SC. The role of the lacrimal functional unit in the pathophysiology of dry eye. Experimental eye research. 2004 Mar 1;78(3):409-16. 7. Cho YK, Kim MS. Dry eye after cataract surgery and associated intraoperative risk factors. Korean Journal of Ophthalmology. 2009 Jun 1;23(2):65-73. 8. Kohlhaas M. Corneal sensation after cataract and refractive surgery. Journal of Cataract & Refractive Surgery. 1998 Oct 1;24(10):1399-409. 9. Sutu C, Fukuoka H, Afshari NA. Mechanisms and management of dry eye in cataract surgery patients. Current opinion in ophthalmology. 2016 Jan 1;27(1):24-30. 10. Venugopal KC, Krishnaraj PA, Chandan N. Evaluation of Dryness of Eyes after Manual Small Incision Cataract Surgery with Corneoscleral Tunnel Incision. Journal of Clinical & Diagnostic Research. 2012 Aug 1;6(6). 11. Kusano M, Uematsu M, Kumagami T, Sasaki H, Kitaoka T. Evaluation of acute corneal barrier change induced by topically applied preservatives using corneal transepithelial electric resistance in vivo. Cornea. 2010 Jan 1;29(1):80-5. 12. Kawahara A, Utsunomiya T, Kato Y, Takayanagi Y. Comparison of effect of nepafenac and diclofenac ophthalmic solutions on cornea, tear film, and ocular surface after cataract surgery: the results of a randomized trial. Clinical Ophthalmology (Auckland, NZ). 2016;10:385. 13. Lee JE, Kim NM, Yang JW, Kim SJ, Lee JS, Lee JE. A randomised controlled trial comparing a thermal massager with artificial teardrops for the treatment of dry eye. British Journal of Ophthalmology. 2014 Jan 1;98(1):46-51. 14. Li XM, Hu L, Hu J, Wang W. Investigation of dry eye disease and analysis of the pathogenic factors in patients after cataract surgery. Cornea. 2007 Oct 1;26:S16-20. 15. Kato K, Miyake K, Kondo N, Asano S, Takeda J, Takahashi A, Takashima Y, Kondo M. Conjunctival goblet cell density following cataract surgery with diclofenac versus diclofenac and rebamipide: a randomized trial. American journal of ophthalmology. 2017 Sep 1;181:26-36. 16. Congdon NG, Schein OD, Von Kulajta P, Lubomski LH, Gilbert D, Katz J. Corneal complications associated with topical ophthalmic use of nonsteroidal antiinflammatory drugs. Journal of Cataract & Refractive Surgery. 2001 Apr 1;27(4):622-31. 17. Jee D, Park M, Lee HJ, Kim MS, Kim EC. Comparison of treatment with preservative-free versus preserved sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops after cataract surgery in patients with preexisting dry-eye syndrome. Journal of Cataract & Refractive Surgery. 2015 Apr 1;41(4):756-63. 18. Pianini V, Passani A, Rossi GC, Passani F. Efficacy and safety of netilmycin/dexamethasone preservative-free and tobramycin/dexamethasone-preserved fixed combination in patients after cataract surgery. Journal of ocular pharmacology and therapeutics. 2010 Dec 1;26(6):617-21. 19. Zhang R, Park M, Richardson A, Tedla N, Pandzic E, de Paiva CS, Watson S, Wakefield D, Di Girolamo N. Dose-dependent benzalkonium chloride toxicity imparts ocular surface epithelial changes with features of dry eye disease. The ocular surface. 2019 Nov 15. 20. Kim MS, Kim HK, Kim JM, Choi CY. Comparison of contamination rates between preserved and preservative-free fluoroquinolone eyedrops. Graefe's Archive for Clinical and Experimental Ophthalmology. 2013 Mar 1;251(3):817-24. 21. Baveja A, Batra N. A comparative study of tear film parameters before and after small incision cataract surgery and phacoemulsification. J. Evid. Based Med. 2017;4(26):1510-3. 22. Jayshree MP, Shivkumar H, Monalisha P, Mallikarjun S. A prospective study of dry eye after manual small incision cataract surgery in rural population of Bagalkot. J Clin Res Ophthalmol. 2017;4(2):025-9. 23. Movahedan A, Djalilian AR. Cataract surgery in the face of ocular surface disease. Current opinion in ophthalmology. 2012 Jan 1;23(1):68-72. 24. Park Y, Hwang HB, Kim HS. Observation of influence of cataract surgery on the ocular surface. PLoS One. 2016;11(10). 25. Sitompul R, Sancoyo GS, Hutauruk JA, Gondhowiardjo TD. Sensitivity change in cornea and tear layer due to incision difference on cataract surgery with either manual small-incision cataract surgery or phacoemulsification. Cornea. 2008 Sep 1;27:S13-8. 26. Miyake K, Yokoi N. Influence on ocular surface after cataract surgery and effect of topical diquafosol on postoperative dry eye: a multicenter prospective randomized study. Clinical ophthalmology (Auckland, NZ). 2017;11:529. 27. Foulks GN, Bron AJ. Meibomian gland dysfunction: a clinical scheme for description, diagnosis, classification, and grading. The ocular surface. 2003 Jul 1;1(3):107-26. 28. Han KE, Yoon SC, Ahn JM, Nam SM, Stulting RD, Kim EK, Seo KY. Evaluation of dry eye and meibomian gland dysfunction after cataract surgery. American journal of ophthalmology. 2014 Jun 1;157(6):1144-50. 29. Kim JS, Lee H, Choi S, Kim EK, Seo KY, Kim TI. Assessment of the tear film lipid layer thickness after cataract surgery. InSeminars in ophthalmology 2018 Jan 1. Taylor & Francis. 30. Chung YW, Oh TH, Chung SK. The effect of topical cyclosporine 0.05% on dry eye after cataract surgery. Korean Journal of Ophthalmology. 2013 Jun 1;27(3):167-71. 31. Chee SP, Ti SE, Sivakumar M, Tan DT. Postoperative inflammation: extracapsular cataract extraction versus phacoemulsification. Journal of Cataract & Refractive Surgery. 1999 Sep 1;25(9):1280-5. 32. Hegde SP, Sekharreddy MR, Kumar MR, Dayanidhi VK. Prospective study of hypermature cataract in Kanchipuram district: Causes of delayed presentation, risk of lens-induced glaucoma and visual prognosis. Kerala Journal of Ophthalmology. 2018 Sep 1;30(3):187. 33. Cho YK, Kim MS. Dry eye after cataract surgery and associated intraoperative risk factors. Korean Journal of Ophthalmology. 2009 Jun 1;23(2):65-73. 34. Ipek T, Hanga MP, Hartwig A, Wolffsohn J, O’Donnell C. Dry eye following cataract surgery: the effect of light exposure using an in-vitro model. Contact Lens and Anterior Eye. 2018 Feb 1;41(1):128-31.