Title: Outcome of Best Corrected Visual Acuity Following Surgically Induced Astigmatism in Manual Small Incision Cataract Surgery

Author: Dr Raktima Baksi (Mandal)

 DOI: https://dx.doi.org/10.18535/jmscr/v8i1.70

Abstract

Background: Age related cataract remains the major cause of blindness throughout the world but the huge backlog exists mostly in the developing world. Manual small incision cataract surgery is the most common surgeries performed worldwide especially in developing countries like India. The aim of Cataract surgery is to provide best possible and early visual outcome. The advantages of MSICS as a low cost “equally effective” technique, makes it an alternative, especially in an unequally developed country like India

Material and Methods: The study was conducted in the Department of Ophthalmology, M.G.M Medical College and L.S.K Hospital, Kishanganj, Bihar. Patients were screened from Ophthalmology Outpatient Department, selected and then admitted in the eye ward of M.G.M Medical College and L.S.K Hospital for undergoing surgery during the period, 1st July 2014 to 30th June 2016. Their visual acuity (Snellen’s chart) and keratometry (in Diopters) recorded pre-operatively and postoperatively on 1st day, 2nd week, 6th week and 3rd month visit. Visual acuity less than 1/60 was tested in terms of finger counting, hand movement and perception of light and projection of rays. The study was conducted on a total of 204 patients divided into two groups by the type of incision(frown, linear) and length of incision(6.5mm, 7mm, 7.5mm)

Result: Majority of the eyes achieved a postoperative uncorrected visual acuity of 6/24 or better by the end of 2nd week. It was 86.15% (176 out of 204 eyes) at 2nd week, 84.61% (173 out of 204) at 6th week and 90.76% (185 out of 204). Eyes with an uncorrected visual acuity of 6/9 or better was 24.61% (50 out of 204) at 2nd week, 29.23% (60 out of 204) at 6th week and 46.15% (60 out of 204). 57.57% of patients in the Frown Group achieved best corrected visual acuity (BCVA) of 6/9 or better as compared to 50% from the Linear Group whereas 37.5% of patients in the Linear Group achieved BCVA 6/12 to 6/24 as compared 33.33% from the Frown Group.

The Linear Incision Group consisted 100 eyes of 100 patients of which 54 were males and 46 were females. The age group ranges from 35 to 70 years with a mean age of 52.31 years whereas Frown Incision Group consisted of 104 eyes of 104 patients of which 52 were males and 52 were females. The age group ranged from 32 to 69 years with a mean age of 53.75 years. The age difference between the Linear and Frown group was found to be statistically insignificant (p>0.05)

Conclusion: The conclusions reached in this study are that best corrected visual acuity at the end of 6 weeks was found to be about 6/9 compared to initial first postoperative day 1 where it was found to be 6/36 or 6/60.Best corrected visual acuity remained almost constant after 6 weeks postoperatively and at the end of our study at 3 months.

Keywords: visual acuity, surgically induced astigmatism.

References

  1. Thylefors B, Negrel AD, Pararajaesegram R, et al. Global data on blindness. Bull World Health Organization. 1996; 74:319-41.
  2. Minasain DC, Mehra V. 8 million blinded by cataract each year: Projections of the first epidemiological study of incidence of cataract blindness in India 1990; 74:341-43.
  3. Jose R. National Programme for control of blindness. Indian J Comm. Health. 1997; 3: 5-9.
  4. Steinert RF et al. Astigmatism after small Incision Cataract Surgery: A prospective randomized multicenter comparison of 4 and 6.5 mm incision. Ophthalmol 1991; 98: 417-23.
  5. Abrams D, Astigmatism. In Duke Elders Practice of Refraction. 9th Churchill Livingstone. Edin Lon NY 1978; 52.
  6. Oshika et al. Current trends in cataract and refractive surgery in Japan.1998 Survey. Jpn j ophthalmol 44: 268-276
  7. Uusitalo RJ, Tarkkanen A. Outcomes of small incision cataract surgery. J Cataract Refract Surg 1998 Feb; 24 (2): 212-21.
  8. Zawar SV, Gogate P. Safety and efficacy of temporal manual small incision cataract surgery in India.Eur J Ophthalmol. 2011;21(6):748–753.
  9. Rohatgi J, Gupta VP, Sangma D. A prospective randomized comparative study of manual SICS using 6 mm frown versus 5 mm modified Chevron Incision.AIOS Proceedings. 2008
  10. Venkatesh R, Tan CS, Sengupta S, Ravindran RD, Krishnan KT, Chang DF. Phacoemulsification versus manual small-incision cataract surgery for white cataract. J Cataract Refract Surg 2010; 36:1849–1854.

Corresponding Author

Dr Raktima Baksi (Mandal)

RMO-CT (Tutor), Dept. of Ophthalmology, Rampurhat Government Medical College, Birbhum