Phototherapeutic Keratectomy for Granular Dystrophy Recurrence after Penetrating Keratoplasty

Varsha Rathi DO, P K Vaddavalli MS, S Murthy MS, V S Sangwan, MS

Cornea and Refractive Surgery ServicesL V Prasad Eye Institute, Hyderabad, AP India

The authors have no financial interest in the subject matter of this poster

•Corneal dystrophies are known to recur following keratoplasty, and granular dystrophy (GCD) is the slowest of these• Prior to Phototherapeutic Keratectomy (PTK), dystrophies were managed with either lamellar or penetrating keratoplasty (PKP)•Since the recurrences are superficial, retreatment with an excimer laser is possible in these cases without the complications of PKP

Introduction

PurposeOur study aimed to assess clinical and visual outcome and time taken for visually significant recurrence of GCD

Pre PTK

Materials and Methods• Retrospective study of patients who underwent

PTK for recurrence of GCD after keratoplasty• Either NIDEK EC 5000 or Bausch & Lomb

Technolas 217z excimer laser machine was used for the PTK

Surgical procedure : PTK •Under strict aseptic precautions, the epithelium was debrided manually with a hockey-stick knife• After 60 to 70 % of targeted ablation, patients were reassessed for clarity of the central visual axis and the ablation was continued if required•Hydroxypropyl methylcellulose 0.7% was used as masking fluid and it was replenished as and when required during the procedure

Surgical procedure : PTK • The endpoint was reached when either the graft

was clear or had minimal non confluent deposits in the central visual axis

• Topical homatropine hydrobromide 2%, diclofenac sodium 0.3% and ofloxacin hydrochloride 0.3% were instilled

• Bandage contact lens (BCL) or a daily pressure patch was used till the defect healed 1

• BCLs were removed after a week. • Three patients had Amniotic membrane grafts

(AMG) performed in conjunction with PTK ; sutured with 10 O Vicryl suture and BCL were placed for a week 2

1 Vyas SP, Rathi V. Phototherapeutic keratectomy for Granular Dystrophy. Asian J Ophthalmol 2008; 10: 123.5.2 Vyas S, Rathi V. Combined phototherapeutic keratectomy and amniotic membrane grafts for symptomatic bullous keratopathy. Cornea 2009; 28: 1028.31.

Results • n= 10 eyes of 6 patients (4 males and 2 females) • Mean age at the time of PKP was 32.67 ± 10.17 years (range,

19-50). • Mean follow up after PTK was 93.3 ± 60.25 months (range 5-

152 months). This follow up is the time elapsed between the first PTK and the last follow up visit

• The postoperative visual acuity improved after PTK in all the eyes except for one patient, who had undergone AMG

– None of the eyes lost BCVA after pure PTK procedure; two eyes had decreased visual acuity of more than 2 lines when AMG was performed.

– These eyes had improved visual acuity of more than 2 lines after PTK with AMG but the improvement was less compared to the improvement in visual acuity when PTK alone was performed earlier.

• Mean BCVA before the first PTK was 20/200(SD, 20/80) (See Table 1)

Table 1

EyeBCVA before PTK

BCVA after first PTK

BCVA before second PTK

BCVA after second PTK

BCVA before third PTK

BCVA after third PTK

Case 1 OD 20/200 20/60 20/200 20/60 NA NA

Case 1 OS20/80 20/80* NA NA NA NA

Case 2 OS20/200 20/40 NA NA NA NA

Case 3 OD20/70 20/40 20/100 20/40 20/125 20/40

Case 3OS20/80 20/30 20/200 20/40 20/125 20/20

Case 4 OD20/80 20/30 20/125 20/40 20/80 20/40

Case 4 OS20/200 20/40 20/125 20/30 20/60 20/40

Case 5 OD20/2000 20/40 20/60 20/20 20/400 20/50 *

Case 5 OS20/2000 20/30 20/160 20/80* NA NA

Case 6 OS20/100 20/60 NA NA NA NAThe best corrected visual acuity before the first PTK and after subsequent PTK procedure/s ; NA – not

applicable ; * Reduced visual acuity when amniotic membrane graft was used

Visual acuity before and after PTK procedures

Refractive Outcome

• Mean spherical equivalent after last PTK was 1.33 DS (range: - 5.00DS to +8.00 DS)

• Mean hyperopia noted was 4.30 DS (range: 1.5 to 8.00 DS) in five eyes

• Mean myopia noted was -2.43 DS (range -0.50 to -5.00 DS) in four eyes

• In one eye, refraction was not possible after PTK and AMG

Visually significant recurrence of GCD in graft

necessitating PTK• Duration between PKP and first PTK was 95.9 ± 37.42 months. • Mean duration between first and second PTK was 62.12 ± 34.41 months• Mean duration between second and third PTK was 42.8 ± 13.54 months

Complications

• Graft rejection : in one eye Five months after PTK, cleared after treatment with steroids. Patient underwent repeat PTK in the same eye after 115 months with good outcome

• Diffuse haze was noted in all patients with mean BCVA of 20/40

• No ectasia was noted even after repeat PTK procedures

• Post PTK

Discussion• Post PTK BCVA was significantly better than the pre PTK

BCVA The first PTK was performed in our series 95.9 ± 37.42 months after PKP (range 37 – 108 months)

• Considering the retrospective nature of the study, only the visually significant recurrences were taken into consideration; subsequently repeat PTKs were performed at an interval of 62.13 ± 34.42 months (range 17 – 84 months) and 42.8 ± 13.53 months ( range 24 – 60 months)

• With multiple recurrences after PTK in eyes with previous keratoplasty, PTK can be repeated safely as in our series, provided the corneal thickness is adequate.

• As the corneal thickness increases with the recurrence, repeat PTK procedures are theoretically possible

Discussion (Continued)

• Dinh et al reported no significant recurrences after PTK in eyes with granular dystrophy with previous PKP

• In our study, seven eyes had repeat PTK 3 • We observed haze in all patients after PTK though

average visual acuity being 20/40• AMG may help reduce scarring but in the three

eyes, the haze persisted even with AMG. Although the visual acuity improved or remained stable with AMG, it was less when PTK was performed alone

3 Dinh R, Rapuano CJ, Cohen EJ et al. Recurrence of corneal dystrophy after excimer laser phototherapeutic keratectomy. Ophthalmology 1999; 106: 1490.7

Conclusion

• PTK appears to be a safe and effective procedure for the treatment of recurrent GCD in a graft and can be repeated a number of times as is seen in our series with predictable improvement in the BCVA. Induced hyperopia was seen only in five out of ten eyes.

• AMG did not help in our series; however, the number of eyes is less ( limitation of the study)

• With the successive procedures, the time interval for repeat PTK is shortened. Once PTK has reached its lower limit for the residual stromal bed thickness, a deep anterior lamellar keratoplasty or PKP can be performed to restore vision.