Sixty eight patients had undergone corneal regrafts at our centre during the study period. Of these, 50 patients (73.5 %) (41 males and 9 females) had a regular follow-up with us of which, 3 patients had undergone bilateral corneal regrafts and these were included in the study (N = 53 eyes). The primary keratoplasty was performed at our centre in 39 eyes of 36 patients and 14 patients were referred from other centres after failure of the primary graft.
The mean age of the patients at the time of repeat penetrating keratoplasty was 45.2 ± 16.5 years. The mean follow-up after regraft was 1.54 ± 0.68 years. Of a total of 53 eyes, 37 eyes had one corneal regraft, 14 had two corneal regrafts and two eyes had undergone three regrafts each (i.e. multiple regrafts in 16 eyes). Forty-eight eyes had undergone other associated intraocular procedures such as goniosynechiolysis (32 eyes), iridectomy with pupilloplasty (7 eyes), cataract extraction (7 eyes) and anterior vitrectomy (11 eyes) at the time of regraft.
The most common indication for primary penetrating keratoplasty in these eyes was vascularized corneal scars (35 of the 53 eyes; 66%) followed by perforations secondary to microbial keratitis (6/ 53; 11.3%) (Table ). The most common cause of vascularized corneal scars was healed microbial keratitis (non-herpetic) (37.1%), followed by herpetic keratitis (31.4%) (Table ). The amount of vascularization was variable. Fifteen eyes showed a single quadrant deep vascularization along with one quadrant of superficial vascularization; eleven eyes showed one quadrant deep vascularization and 2 quadrants of superficial vascularization; 8 eyes had 2 quadrants of deep vascularization and 2 quadrants of superficial vascularization, and 1 eye had 3 quadrants of deep and 3 quadrants of superficial corneal vascularization.
Indications for primary corneal transplantation in corneal regrafts
The failure of primary graft was attributable to poor ocular surface in 18 eyes (33.9%), recurrence of herpetic keratitis in 8 eyes (15%), perforated graft ulcers in 4 (7.5%), scarring due to graft infection in 4 (7.5%), allograft rejection in 7 eyes (13.2%), endothelial decompensation in 8 eyes (15 %) and raised intraocular pressure in 4 eyes (7.5%). Since a high proportion of the grafts failed due to poor ocular surface, all these eyes were put on intensive (1 hourly) preservative free lubricants and repeat grafting was performed only after these eyes attained a reasonably good ocular surface. Two eyes with failed primary graft and ocular surface problems required entropion surgery and in two eyes permanent punctual plugs were inserted before regraft.
After repeat graft, these eyes were prescribed 1 hourly preservative free lubricant for 3 months and QID later along with topical chloramphenicol and topical dexamethasone QID each for 3 months and BD each later.
Of the 53 eyes with regrafts, 28 eyes (52.8%) had clear grafts at the end of follow up of which, 25 eyes (89.3%) had undergone single regraft and 3 eyes had multiple regrafts (Table ). The reasons for failure in the remaining 25 eyes (47.2 %) was recurrence of herpetic infection in 9 eyes (36%), uncontrolled glaucoma in 5 eyes (20%), allograft rejection in 4 eyes (16%), perforated graft ulcers in 3 eyes (12%), endothelial decompensation in 2 eyes (8%), poor ocular surface in 2 eyes (8%). The survival of the regrafts has been depicted in Figure .
Outcome of corneal regrafting surgery
The pre-operative visual acuity ranged from light perception to 1/60. The best corrected visual acuity of the 28 clear grafts ranged from 4/60 to 6/9. Only five eyes (9.4%) achieved a BCVA of 6/18 or better at the end of 1 year after re graft, of which all had single regrafts (Table ). In twenty-five eyes with failed repeat grafts, visual acuity ranged from light perception to 1/60.
Visual Acuity of single Vs multiple regrafts at last follow up
Causes of suboptimal visual outcome (post-refraction) in regrafts that remained clear (grade 3/4) was poor ocular surface (9 eyes), post penetrating keratoplasty astigmatism (6 eyes), macular scarring (5 eyes), treated graft rejection (4 eyes) and post-penetrating keratoplasty glaucoma (4 eyes).