[show abstract][hide abstract] ABSTRACT: To compare higher order aberrations (HOAs) caused by the anterior and posterior corneal surfaces after conventional penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and automated lamellar therapeutic keratoplasty (ALTK) in patients undergoing corneal transplantation for keratoconus (KC).
This retrospective, observational, cross-sectional study included one eye of the following subjects: 40 patients with KC, 23 KC patients after PK, 17 KC patients after DALK, 18 KC patients after ALTK, and 38 healthy controls. All underwent imaging with a rotating Scheimpflug camera (at least 6 months after complete suture removal in grafted subjects) to assess the HOAs from the anterior and posterior corneal surfaces within the central 4-mm and 6-mm zones. The conversion of the corneal elevation profile into corneal wavefront data was performed using Zernike polynomials. Total and third- and fourth-order HOAs were considered. The root mean square of the Zernike vector magnitude, expressed in micrometers, was used. Differences among groups were assessed using the Kruskal-Wallis and Duncan multiple range tests. Statistical significance was defined as p < 0.05.
In both 4-mm and 6-mm central zones, the total HOAs from the anterior corneal surfaces were significantly lower in DALK than in ALTK and PK groups (p < 0.05). The total HOAs from the posterior corneal surface were comparable amongst postoperative groups (p > 0.05). The aberration components that were significantly greater included coma in the KC and ALTK eyes, trefoil and coma in the DALK eyes, and trefoil in the PK eyes.
The corneal anterior surface optical quality appeared significantly better after DALK than after ALTK and PK.
Optometry and vision science: official publication of the American Academy of Optometry 03/2013; 90(3):293-301. · 1.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chemical burns cause depletion of limbal stem cells and eventually lead to corneal opacity and visual loss. We investigated the long-term effectiveness of autologous cultured limbal stem cell grafts in patients with limbal stem cell deficiency.
Prospective, non-comparative interventional case series.
Sixteen eyes from 16 patients with severe, unilateral limbal stem cell deficiency caused by chemical burns.
Autologous ex vivo cultured limbal stem cells were grafted onto the recipient eye after superficial keratectomy.
Clinical parameters of limbal stem cell deficiency (stability/transparency of the corneal epithelium, superficial corneal vascularization and pain/photophobia), visual acuity, cytokeratin expression on impression cytology specimens and histology on excised corneal buttons.
At 12 months post-surgery, evaluation of the 16 patients showed that 10 (62.6%) experienced complete restoration of a stable and clear epithelium and 3 (18.7%) had partially successful outcomes (re-appearance of conjunctiva in some sectors of the cornea and instable corneal surface). Graft failure (no change in corneal surface conditions) was seen in three (18.7%) patients. Penetrating keratoplasty was performed in seven patients, with visual acuity improving up to 0.8 (best result). For two patients, regeneration of the corneal epithelium was confirmed by molecular marker (p63, cytokeratin 3, 12 and 19, mucin 1) analysis. Follow-up times ranged from 12 to 50 months.
Grafts of autologous limbal stem cells cultured onto fibrin glue discs can successfully regenerate the corneal epithelium in patients with limbal stem cell deficiency, allowing to perform successful cornea transplantation and restore vision.
Clinical and Experimental Ophthalmology 06/2011; 40(3):255-67. · 1.96 Impact Factor