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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 7  |  Issue : 2  |  Page : 65-70

Effect of mitomycin-c-assisted sutureless trabeculectomy on keratometry and axial length


1 Department of Ophthalmology, S P Medical College and Hospital, Bikaner, Rajasthan, India
2 S.M.O, Government Hospital, Chittorgarh, Rajasthan, India

Date of Web Publication28-Apr-2017

Correspondence Address:
Anant Sharma
Department of Ophthalmology, S P Medical College and Hospital, Bikaner, Rajasthan
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/AIHB.AIHB_42_16

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  Abstract 

Aim: Glaucoma is defined as chronic, progressive optic neuropathy caused by a group of ocular conditions, which leads to damage of the optic nerve with loss of visual function. This study was conducted to find out the changes in corneal curvature, axial length and intraocular pressure. Materials and Methods: The present study was conducted in the Department of Ophthalmology, S P Medical College and Associated Group of Hospitals, Bikaner. A total of fifty cases of either age- and sex-matched controls were selected for this study. These cases were divided into two groups: Group A (sutureless trabeculectomy with mitomycin-C [MMC]) and Group B (sutureless trabeculectomy without MMC). Results: The mean post-operative intraocular pressure (IOP) was lowered in MMC-treated eyes when compared to control at 1½ months. The IOP reduction was greater in the MMC-treated eyes (13.25 mmHg at 1½ months) as compared to control Group B (16.9 mmHg at 1½ months). Comparing results with the present study, it was found that success rate in MMC-treated eyes was noted in 23 (92%) individuals, in which complete success was in 22 (88%) while qualified success in 1 (4%) and qualified failure in 2 (8%) with mean IOP of 13.2 mmHg at 1½ months, whereas in control group, success rate was noted in 19 (76%) individuals, in which complete success was in 18 (72%) and qualified success in 1 (4%), while qualified failure in 6 (24%) with mean IOP of 16.9 mmHg at 1½ months after operation. Conclusion: Results of this study are in favour of intraoperative application of MMC during filtration surgery, especially in cases with high-risk failure.

Keywords: Axial length, intraocular pressure, mitomycin-C sutureless trabeculectomy


How to cite this article:
Sharma A, Rawat M, Sharma AK. Effect of mitomycin-c-assisted sutureless trabeculectomy on keratometry and axial length. Adv Hum Biol 2017;7:65-70

How to cite this URL:
Sharma A, Rawat M, Sharma AK. Effect of mitomycin-c-assisted sutureless trabeculectomy on keratometry and axial length. Adv Hum Biol [serial online] 2017 [cited 2020 Jun 2];7:65-70. Available from: http://www.aihbonline.com/text.asp?2017/7/2/65/205394


  Introduction Top


Glaucoma is defined as chronic, progressive optic neuropathy caused by a group of ocular conditions, which leads to damage of the optic nerve with loss of visual function.[1] The most common risk factor is a raised intraocular pressure (IOP). It may be due to increased formation of the aqueous humour, difficulty in its exit or a raised pressure in the episcleral veins. It is a leading cause of irreversible blindness worldwide.[2] It is estimated that 66.8 million people worldwide have glaucoma and that 6.7 million are bilaterally blind. In India, statistics in the year 2000 shows that glaucoma accounted for 1.52% of blindness (8.1 million blind individuals).[3]

Advances in genetics, diagnostics, pharmacology, surgical techniques and laser have revolutionised our understanding of the disease.[4] However, as the disease remains incurable, the mainstay of the treatment remains early detection and treatment.

Glaucoma is not a single disease process but a group of disorders in which IOP is raised above the tolerance limit of the affected eye, resulting in damage to the optic nerve head and irreversible visual field defects.[5]


  Materials and Methods Top


The present study was conducted in the Department of Ophthalmology, S P Medical College and Associated Group of Hospitals, Bikaner. A total of fifty cases of either age- and sex-matched controls were selected for this study. These cases were divided into two groups: Group A (sutureless trabeculectomy with mitomycin-C [MMC]) (study group) and Group B (sutureless trabeculectomy without MMC) (control group). Each group had 25 cases. Sutureless trabeculectomy in all cases was performed. This study was conducted to find out the changes in corneal curvature, axial length and intraocular pressure.


  Results Top


In Group A, the male:female ratio was 0.92:1. The maximum number of cases were between the fifth and eighth decade in both sexes [Table 1]a. In Group B, male:female ratio was 0.66:1.0 and a maximum number of cases were between the fifth and eighth decade in both sexes [Table 1]b and [Table 2]a.
Table 1:

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Table 2:

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In Group B, two cases were of primary open-angle glaucoma, seven cases were of primary angle-closure glaucoma, 13 cases were of lens-induced glaucoma and three cases were of secondary glaucoma. In Group A, two cases were of primary open-angle glaucoma, six cases were of primary angle-closure glaucoma, 11 cases were of lens-induced glaucoma and six cases were of secondary glaucoma [Table 2]b.

Group A – Pre-operative astigmatism in all 25 cases was <3 D. Fifteen cases had <1.5 D and ten cases had 1.5–3 D. Fourteen cases had astigmatism against-the-rule while 11 cases had with-the-rule astigmatism. The mean astigmatism was 1.20 [Table 3]a and [Table 3]b.
Table 3:

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At 1½-month post-operative week, astigmatism continuously falls. There was statistically significant fall in astigmatism (P = 0.0001). Twenty-three cases have against-the-rule astigmatism. The surgically induced astigmatism at 1½ months remained statistically highly significant (P < 0.001) [Table 4]a.
Table 4:

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The study shows a sharp increase in astigmatism post-operatively in 2 weeks, but thereafter, it continuously falls till the last follow-up of 1½ months. At every follow-up, changes were approximately similar. This shows that although there was a statistically significant increase in surgically induced astigmatism initially, it continuously falls at a stable rate. The surgically induced astigmatism at 1½ months was 0.96 D (mean post-operative - mean pre-operative). Pre-operatively, 11 cases had with-the-rule astigmatism, while post-operative 1½ months, only two cases had with-the-rule astigmatism. This shows flattening of axis in the direction of incision [Table 4]b.

At post-operatively 1½ months, axial length decreased from 0.21 to 0.62. Pre-operative mean IOP in control Group (B) was 30.26 mmHg while in Group (A) was 28.96 mmHg. The mean post-operative IOP was lowered in MMC-treated eyes when compared to control at 1½ months. The IOP reduction was greater in the MMC-treated eyes (13.25 mmHg at 1½ months) as compared to control Group B (16.9 mmHg at 1½ months).

Group B – Pre-operative astigmatism in 19 cases had <1.5 D, five cases had 1.5–3 D and only one case had more than 3 D. The mean astigmatism was 1.09 D. Twenty-two cases had against-the-rule astigmatism, two cases had no astigmatism and one case had with-the-rule astigmatism [Table 5]a and [Table 5]b.
Table 5:

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At 1½ months, astigmatism decreased significantly (P = 0.001). Twenty-three cases were against–the-rule astigmatism and 2 cases were with–the-rule astigmatism.

Comparison of Group A and B

In paired sample test, it was evident that on comparing pre-operative astigmatism in Group A and Group B, the difference was not statistically significant (P = 0.697).

Surgically induced astigmatism at 1½-month post-operative week in each group was statistically significant (P = 0.0001 and P = 0.009 in Group A and Group B, respectively). The mean induced astigmatism was slightly greater in Group B, but the difference in surgically induced astigmatism between Groups A and B was not statistically significant (P = 0.49). The mean induced astigmatism was against-the-rule in both groups [Table 6]a and [Table 6]b.
Table 6:

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The data on axial length in the two groups were compared at different interval of time after operation. The magnitude of axial length in Group A was 23.08 ± 0.79 and that in Group B was 22.62 ± 1.06 before operation. The data further revealed that there was no difference with respect to this parameter at pre-operative stage (P = 0.09) [Table 7].
Table 7: Axial length changes post-operative at after 1½ months

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One and half months after operation, the respective values were 22.70 ± 0.76 and 22.18 ± 1.03 in Group A and Group B. Statistical analysis revealed that these value were statistically significantly different (P = 0.047).

Based on the above data, it is evident that there was decrease in magnitude of axial length after treatment. The decrease in magnitude was higher in Group B as compared to Group A at 1½ months after treatment.

Comparing results with the present study, it was found that success rate in MMC-treated eyes was noted in 23 (92%) individuals, in which complete success was in 22 (88%) while qualified success in 1 (4%) and qualified failure in 2 (8%) with mean IOP of 13.2 mmHg at 1½ months, whereas in control group, success rate was in 19 (76%) individuals, in which complete success in 18 (72%) and qualified success in 1 (4%), while qualified failure was in 6 (24%) with mean IOP of 16.9 mmHg at 1½ months after operation [Table 8].
Table 8: Intraocular pressure changes post-operative at after 1½ months

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  Discussion Top


This study was conducted to find out the changes in corneal curvature, axial length and intraocular pressure. Lens-induced glaucoma surgery has to be done at the same time for both cataract and glaucoma. Incision-induced astigmatism causes flattening of corneal surface.

Although filtering surgery by modified Cairn's technique is most widely accepted operation of choice in all types of glaucoma, but long-term efficacy is less successful in certain types of glaucoma includes glaucoma in young patients, those with secondary glaucoma angle closure glaucoma, lens-induced glaucoma and in patients requiring re-operations.[6]

Various methods have been advocated for the management of these cases, since most common cause of trabeculectomy failure is excessive scarring of the wound margins leading to a flat non-functioning bleb, the role of MMC in such cases was established by Chen in 1983 MMC as a pharmacological wound modulator by its antiproliferative action against fibroblasts at the wound margins.

In 1990, Chen used MMC as an adjuvant therapy in glaucoma cases, suggesting that it is highly effective in increasing the success rate of the trabeculectomy in cases of poor surgical prognosis.[7]

As this recent report shows markedly improved results, it is decided to conduct a similar study to find out the efficacy of adjuvant use of single intraoperative application of MMC to the filtering site in patients who were considered to be at high risk of surgical failure with routine trabeculectomy and then compare with simple trabeculectomy with MMC applications.

Kook et al., 2001, studied the effect of trabeculectomy with adjunctive MMC on corneal astigmatism and axial length.[8] There was a positive correlation between post-operative axial length and IOP. Eyes with higher pre-operative IOP had a greater decrease in axial length after trabeculectomy with MMC.

In MMC-treated cases, one case developed flat anterior chamber and hyphaema and three cases developed corneal erosion which was cured within a week.


  Conclusion Top


The impact of the present study was that the end results concerning corneal astigmatism after the two different methods (sutureless trabeculectomy with MMC vs. sutureless trabeculectomy without MMC) were quite similar. Age and sex had no role in induced astigmatism. Both methods in regard to astigmatism were equally suited for glaucoma surgery. However, as changes continue in both types up to the last follow-up, the proper evaluation of any technique to modify post-operative astigmatism must consider the long-term evaluation.

Axial length changes were compared in Groups A and B. It suggested that there was a significant decrease of axial length in post-operative period in Group B compared to Group A.

The results of this study are in favour of intraoperative application of MMC during filtration surgery, especially in cases with high-risk failure. However, in order to find the long-term efficacy of this method, a large-scale study must be carried out with a longer duration of follow-up.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Hollows FC, Graham PA. Intra-ocular pressure, glaucoma, and glaucoma suspects in a defined population. Br J Ophthalmol 1966;50:570-86.  Back to cited text no. 1
    
2.
Lindblom B, Thorburn W. Prevalence of visual field defects due to capsular and simple glaucoma in Hälsingland, Sweden. Acta Ophthalmol (Copenh) 1982;60:353-61.  Back to cited text no. 2
    
3.
Tielsch JM, Sommer A, Katz J, Royall RM, Quigley HA, Javitt J. Racial variations in the prevalence of primary open-angle glaucoma. The Baltimore Eye Survey. JAMA 1991;266:369-74.  Back to cited text no. 3
    
4.
Klein BE, Klein R, Sponsel WE, Franke T, Cantor LB, Martone J, et al. Prevalence of glaucoma. The Beaver Dam Eye Study. Ophthalmology 1992;99:1499-504.  Back to cited text no. 4
    
5.
Coffey M, Reidy A, Wormald R, Xian WX, Wright L, Courtney P. Prevalence of glaucoma in the West of Ireland. Br J Ophthalmol 1993;77:17-21.  Back to cited text no. 5
    
6.
Dielemans I, Vingerling JR, Wolfs RC, Hofman A, Grobbee DE, de Jong PT. The prevalence of primary open-angle glaucoma in a population-based study in the Netherlands. The Rotterdam Study. Ophthalmology 1994;101:1851-5.  Back to cited text no. 6
    
7.
Chen CW. Enhanced intraocular pressure controlling effectiveness of trabeculectomy by local application of mitomycin-C in refractory glaucoma. J Ocul Pharmacol Ther 1990;6:175-8.  Back to cited text no. 7
    
8.
Kook MS, Kim HB, Lee SU. Short-term effect of mitomycin-C augmented trabeculectomy on axial length and corneal astigmatism. J Cataract Refract Surg 2001;27:518-23.  Back to cited text no. 8
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]



 

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