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Singapore National Eye Centre. Anterior Lamellar Keratoplasty over Penetrating Keratoplasty for Optical, Therapeutic and Tectonic Indications. Marcus Ang, MBBS, MMed Jodhbir S Mehta, FRCOphth Anshu Arundhati , FRCSEd Donald Tan, FRCOphth. The authors have no financial interest.
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Singapore National Eye Centre Anterior Lamellar Keratoplasty over Penetrating Keratoplasty for Optical, Therapeutic and Tectonic Indications Marcus Ang, MBBS, MMed Jodhbir S Mehta, FRCOphth AnshuArundhati, FRCSEd Donald Tan, FRCOphth The authors have no financial interest.
Purpose • Repeat penetrating keratoplasty (PK) is becoming a leading indication for corneal grafting. • However, the survival graft rates and visual outcome is often poor compared to the initial PK. • Anterior lamellar keratoplasty (ALK) over the previous PK may be considered as an alternative to a repeat PK in selected patients. We present a series of patients who underwent an ALK over a PK, for a variety of optical, therapeutic and tectonic indications requiring anterior stromal replacement of the previous penetrating graft.
Methods • We reviewed all patients who underwent ALK after an initial PK in Singapore National Eye Center (SNEC) between January 1991 and May 2008. • Data included patient demographics, ophthalmic history, and indications and details of surgery, preoperative and postoperative Snellen visual acuity (VA) with refraction. • Outcome measures were: • Final VA, • Graft failure (ALK, PK or both) - defined as an irreversible loss of central graft clarity from any cause, irrespective of the level of VA • Successful restoration of tectonic integrity in tectonic indications • Eradication of infection in therapeutic cases
Surgical Techniques a) Manual Deep Anterior Lamellar Keratoplasty (DALKm) (n= 7). This was performed using a previously described technique.1 b) Automated lamellar therapeutic keratoplasty (ALTK) (n = 1) A modified two-stage ALTK using a previously described technique was performed.2 • The lamellar grafts were centered on the previous PK in 6 cases, or on the visual axis (2 cases) in those with decentered PK. • Five of 8 eyes had oversized ALK grafts compared to PK [Mean 0.85mm (0.50-1.50mm)] • Parthasarathy A, Tan D. Simplified technique for deep lamellar keratoplasty. Cornea. 2008 Apr;27(3):387-8; • Tan DT, Ang LP. Modified automated lamellar therapeutic keratoplasty for keratoconus: a new technique. Cornea. 2006 Dec; 25(10): 1217-9.
Results Eight eyes of 8 Asian patients (6 females and 2 males) with a mean age of 53 years (range 15-84). Mean interval time between the initial PK and subsequent ALK was 72 ± 64 months. Mean follow-up duration after ALK was 27±22 months. Final BCVA improved in 5 eyes, with gain of 2 or more lines of BCVA (range, 2–6 lines) and unchanged in 2 eyes after the subsequent ALK. Mean preoperative logMAR BCVA was 1.52±0.25 improved to 0.87±0.26 postoperatively (P= 0.032).
A: Patient 1 with recurrence of granular dystrophy 21 years post-PK; B: Patient 1, two months postoperatively following ALTK on previous PK. C: Patient 2 with candida infection 1 month post-PK, on medical therapy for 18 days. D: Patient 2, 1 month postoperatively following DALKm on previous PK, with clear graft.
A: Patient 5 with corneal scarring from previous infective keratitis, 13 years post-PK B: 4 weeks post-DALKmon previous PK, showing temporary endothelial dysfunction C: 3 months postoperatively complicated by candida infection- infiltrate at 7 o’clock. D: 3 months postoperatively following DALKm and graft repositioning, and intra-corneal amphotericin injection.
Discussion In our series of patients who had undergone an ALK following a PK, patients managed to achieve successful visual rehabilitation without the need for a repeat PK. 3 of 8 (38%) eyes managed to attain post-ALK BCVA comparable to BCVA post-PK (Best vision post-PK before disease recurrence or infection) with most (5 of 8 eyes) patients having improved post-ALK BCVA. Advantages and disadvantages of of ALK over PK versus a repeat PK is discussed in Table 2. The ALTK technique described can reduce irregular astigmatism due to scarring/folds at the donor-host corneal interface.
Table 2: Discussion on advantages of performing ALK over PK as compared to repeat PK
Conclusion ALK may be a viable and safer option for a variety of optical, therapeutic and tectonic indications as compared to a repeat PK in a select group of patients. Thank you A presentation by: