Abstract
Purpose: :
To determine if endothelial cell density is a predictor of the clinical need for fenestration in the design of a scleral lens ocular surface prosthesis for visual rehabilitation after penetrating keratoplasty.
Methods: :
A retrospective case review was performed in 45 consecutive new patients (62 eyes) seen at this center from 08/21/2008 to 7/13/2009 for visual rehabilitation after penetrating keratoplasty. Fenestration is selected by the clinician based on report of colored haloes after several hours of lens wear and association with microcystic epithelial edema on biomicroscopy. In addition to improving oxygenation of tear film, fenestration reduces suction effects on epithelium. Patient age, sex, indication for penetrating keratoplasty, years of graft survival, pseudophakia, central pachymetry, endothelial cell density, pre and post-fit BCVA, and incorporation of fenestration in prosthesis design were recorded.
Results: :
The ratio of males to females was 23:22. Age range was 27-75 years (mean=51.76 years). Graft survival range was 1-40 years (mean=14.6 +/-10.5). 71% were phakic, 26% were pseudophakic and 3% were aphakic. Indications for penetrating keratoplasty were ectasia (73%), opacity (11%), Fuchs' dystrophy (10%) and ocular surface disease (6%). 69% were fitted with fluid-ventilated design; 31% required fenestration. Endothelial cell densities ranged from 472-2918 cells/mm2. Decreased endothelial cell density relates to need for fenestration (independent samples t-test, t(60)= 1.56, p=0.123) and is statistically significant in regard to need for fenestration with the removal of one outlier with mitigating circumstances (independent samples t-test, t(59)= 2.46, p=0.017). Increased years of graft survival (independent samples t-test, t(60)= 2.46, p=0.017) correlated with need for fenestration. Mean pre-BOSP BCVA was logMAR 0.70+/- 0.62, whereas mean post-BOSP BCVA was logMAR 0.18 +/- 0.41. This improvement was significant (paired samples t-test, t(61)= 7.69, p<0.001). Central pachymetry, fitting success rate and wearing status at 6 months are reported.
Conclusions: :
Endothelial cell density and duration of graft survival correlate with need for fenestration in design of an ocular surface prosthesis in visual rehabilitation of penetrating keratoplasty. Further study of endothelial and epithelial response to the prosthesis, and to use of fenestration to improve device tolerance in grafted eyes, is warranted.
Keywords: contact lens • cornea: clinical science • transplantation