Quality of Vision in Eyes After Selective Lamellar Keratoplasty

Abstract

With the increasing popularity of selective lamellar keratoplasty procedures, it is important to characterize the optical differences among penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet stripping automated endothelial keratoplasty (DSAEK). The impact of optical differences on the visual acuity (VA) in eyes after keratoplasty is significant. Quantitative evaluation of corneal higher-order aberrations (HOAs) of anterior and posterior surfaces using a rotating Scheimpflug-based corneal topographer, showed that eyes that undergo DSAEK have lower anterior corneal HOAs compared with eyes subjected to PK or DALK. In DSAEK, the anterior corneal surfaces are not replaced, which is in contrast to PK or DALK, where they are replaced. Through evaluation of corneal scatter with a densitometry program associated with the rotating Scheimpflug-based corneal topographer, 3 characteristic patterns of corneal scatter were found in eyes that had undergone keratoplasty. Investigation of the impact of corneal HOAs and corneal scatter on VA after keratoplasty showed that the VA was correlated significantly with corneal scatter.

Determinants of visual quality after endothelial keratoplasty

“…68 42% DSAEK eyes exhibited an anterior peak pattern, with a single sharp peak in the anterior cornea. 68 Visual acuity correlated significantly with corneal scatter, and the results suggested that increased light scatter originated from both the anterior and posterior cornea after DSAEK. 68 The effects of light scatter on visual acuity and contrast sensitivity may be more apparent in everyday life, with varying ambient lighting and sources of glare in the environment.…”

“…54,138 Although correlation has been demonstrated between anterior corneal HOAs and postoperative BCVA, 84,108,137,139 several studies have failed to find a similar association between posterior corneal HOAs and postoperative BCVA. 68,81,84,133,137 Despite this, the impact of the posterior corneal surface on visual outcomes should not be ignored. …”

“…131 Koh et al investigated corneal light scatter by using the 'densitometry' program of the rotating Scheimpflug camera to examine patterns of backscattered light after PK, DALK and DSAEK. 68 Transmitted light attenuation (or "corneal density", as referred to in the original study) was graded from 0 (no clouding) to 100 (completely opaque). 68 A normal pattern (gentle slope from periphery with a slight peak in the anterior cornea) was seen in all control eyes and 75% of PKP eyes, whereas 57% of DSAEK eyes and 92% of DALK eyes had a "double-peak" pattern, with two sharp peaks in the anterior and posterior cornea.…”

“…68 Transmitted light attenuation (or "corneal density", as referred to in the original study) was graded from 0 (no clouding) to 100 (completely opaque). 68 A normal pattern (gentle slope from periphery with a slight peak in the anterior cornea) was seen in all control eyes and 75% of PKP eyes, whereas 57% of DSAEK eyes and 92% of DALK eyes had a "double-peak" pattern, with two sharp peaks in the anterior and posterior cornea. 68 42% DSAEK eyes exhibited an anterior peak pattern, with a single sharp peak in the anterior cornea.…”

Transplante endotelial: em busca de qualidade visual

“…Fatores relacionados à superfície ocular e ao segmento anterior incluindo a dinâmica do filme lacrimal, aberrações corneanas de baixa e alta ordem, opacidades anteriores ou posteriores e descentrações pupilares podem ser responsáveis por resultado visual insatisfatório. 40 Dirisamer et al…”