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  5. FP154 : Visual Outcome After Cataract Surgery in Eyes with a Corneal Graft

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Dr.Samrat Chatterjee, C07146,

Dr. Deepshikha Agrawal

Lens opacification following penetrating keratoplasty is reported in 24 – 68% of patients.[1-3]Cataract extraction in an eye with a corneal graft can challenge the ophthalmic surgeon in many ways. These are related to calculation of correct intra-ocular lens power; intra-operative visibility of the anterior segment and pupillary dilation, placement of the incision, management of posterior pupillary or anterior iris synechia which are often present after therapeutic penetrating keratoplasty (TPK), corneal endothelial protection; and prevention of graft rejection and failure, and good visual outcome in the post-operative period.

The aim of this study is to report the visual outcome in patients with corneal graft undergoing cataract surgery at a later date.

Methods:

This was a retrospective review of medical records of all patients with corneal grafts undergoing cataract surgery in the same eye at a later date at a tertiary care eye institute in central India from 2005 – 2016. The medical records were reviewed for demographic particulars, indications for keratoplasty, type of keratoplasty, type of cataract surgery, visual status pre-and post-operatively, post-operative graft clarity and complications. The procedure for cataract removal was at the discretion of the surgeon. Either extra-capsular cataract extraction (ECCE) with a corneal or limbal incision was preferred in total cataract or poor visibility of the anterior segment or extensive posterior or anterior iris synechiae, or phacoemulsification (PE) through a sclera-corneal tunnel incision in others. The choice of type of intra-ocular lens depended on type of cataract surgery and patient preference. Patients undergoing ECCE underwent rigid PMMA intra-ocular lens implantation while those undergoing PE underwent either acrylic or PMMA intra-ocular lens implantation. Pre-operatively topical steroids were stepped-up in frequency (8 times a day) one week prior to surgery. Intra-operatively cohesive viscoelastic devices and balance salt solution was used to protect the corneal endothelium. Post-operatively patients were treated with oral corticosteroid and frequent topical corticosteroids, which were gradually tapered. Topical corticosteroids were continued in low dose and never discontinued. Topical broad-spectrum antibiotics, commonly 0.3% Ofloxacin was given for 1-2 weeks postoperatively. Topical preservative free lubricants were continued.

The main outcome measure was best spectacle corrected visual acuity(BSCVA). Vision in all patients was recorded with a LogMAR chart under standard illumination. For the purpose of this study, all recorded visual acuity in Snellen equivalent, counting fingers and less than counting fingers was converted to LogMAR values as per the chart given by Holladay.[4]Sub-category analysis included comparison of eyes which had undergone optical penetrating keratoplasty (OPK) with TPK and between ECCE and PE. Statistical analysis included student t test and Fisher’s exact test. A 2-tailed p value less than 0.05 was considered to be statistically significant.

Results:

During the study period 254 patients underwent OPK and 235 patients underwent TPK. Of these 25/489 (5.1%) underwent cataract surgery at a later date. There were 13(52%) males and 12 (48%) females, and the mean age of the group was 42.3 ± 15 years. Eleven (44%) of the eyes had undergone OPK while 14(56%) eyes had undergone TPK. Cataract was removed by PE in 13(52%) eyes and ECCE in 12(48%) eyes. In 24(96%) eyes an IOL was implanted while 1 eye was left aphakic.

Post-operative analysis was done in 24 eyes as 1 patient was lost to follow-up. The mean pre-operative uncorrected visual acuity was 1.42 ± 0.79 LogMAR which improved to 0.59 ±  0.27 LogMAR (p=0.0008) post-operatively. The mean pre-operative BSCVA was 1.60 ± 0.93 LogMAR which improved to 0.31 ±  0.31 LogMAR (p<0.0001) post-operatively. The mean follow-up duration after cataract surgery was 104.9 ±  113.6 (6 – 442) weeks; median: 60 weeks. The mean BSCVA at the last follow-up visit was 0.38 ± 0.34 LogMAR which was significantly (p=0.01) less than the visual acuity achieved soon after cataract surgery. Overall 14(58.3%) patients had best post-operative BSCVA of 20/40 or better, 9(37.5%) patients had BSCVA 20/50- 20/200, 1(4.2%) patient had BSCVA less than 20/200 but better than Counting fingers at 1 feet and no patients had BSCVA less than Counting fingers. At the last follow-up 11(45.8%) patients had best post-operative BSCVA of 20/40 or better, 6(25%) patients had BSCVA 20/50- 20/200, 3(12.5%) patient had BSCVA less than 20/200 but better than Counting fingers at 1 feet and 4(16.7%) patients had BSCVA less than Counting fingers. There was no statistically significant difference (p=0.3) in the mean BSCVA in between patients undergoing PE and ECCE (0.25 ±  0.28 LogMAR versus 0.38 ± 0.34 LogMAR respectively). There was also no statistically significant difference (p=0.2) in the mean BSCVA between patients who had earlier undergone OPK and TPK (0.38± 0.27 versus 0.38 ±0.23± 0.34 LogMARrespectovely).

Post-operatively 3 eyes had graft infiltrate, 2 eyes had corneal allograft rejection, 2 eyes had primary graft failure, 1 eye had wound leak and 1 eye had graft-host junction dehiscence. The allograft rejection in both the patients resolved with intravenous, oral and topical corticosteroids. The infection in eyes with graft infiltrate was controlled with topical anti-microbial agents but the grafts eventually failed. Overall 5 (20.8%) eyes had corneal graft failure.

Discussion:

In the present study 58.3% of patients had BSCVA of 20/40 or better. There was significant improvement in both UCVA and BSCVA after cataract extraction. No difference could be seen between eyes undergoing PE or ECCE or if the corneal grafting was OPK or TPK. The proportion of patients achieving post-operative best corrected visual acuity of 20/40 or better reported in ophthalmic literature ranges from 43 – 81%. [5-8]

However, in the present series there was a significant  trend of reduced vision at long term. This was primarily due to graft failure that occurred in one-fifth of the patients. Corneal allograft rejection was seen in only 2 eyes which could be revered with treatment. The frequency of graft rejection following sequential cataract surgery is reported to range from 0 – 64%, [5-8] but in most instances the rejection episode can be reversed with treatment. However, the 3 eyes with graft infiltrate failed. The endothelium of the corneal graft is always compromised and cataract surgery can result in further endothelial cell loss and eventual graft failure. In 2 eyes, there was primary graft failure and this is related to post-cataract surgery endothelial cell loss. Parmar et al did not report significant differences in graft failure between eyes which had undergone OPK and TPK prior to cataract surgery. [8]

In conclusion, sequential cataract surgery after penetrating keratoplasty appears to give satisfactory visual outcome and is considerably safe.

Reference:

  1. Martin TP, Reed JW, Legault C, et al. Cataract formation and cataract extraction after penetrating keratoplasty. Ophthalmology 1994;101:113-9.
  2. Rathi VM, Krishnamachary M, Gupta S. Cataract formation after penetrating keratoplasty. J Cataract Refract Surg. 1997;23:562-4.
  3. Bajracharya L, Gurung R. Outcome of therapeutic penetrating keratoplasty in a tertiary eye care center in Nepal. Clin Ophthalmol. 2015 Dec 7;9:2299-304.
  4. Holladay JT. Visual acuity measurements. J Cataract Refract Surg. 2004;30:287-90.
  5. Geggel HS. Intraocular lens implantation after penetrating keratoplasty improved unaided visual acuity, astigmatism, and safety in patients with combined corneal disease and cataract. Ophthalmology 1990;97:1460-7.
  6. Hsiao C, Chen JJY, Chen FYF, et al. Intraocular lens implantation after penetrating keratoplasty. Corneal 2001;20:580-5.
  7. Nagra PK, Rapuano CJ, Laibson PL, et al. Cataract extraction following penetrating keratoplasty. Cornea 2004;23:377-9.
  8. Parmar P, Salman A, Kalavathy CM, et al. Outcome analysis of cataract surgery following therapeutic keratoplasty. Cornea 2005;24:123–129.

 

 

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