Visual function after penetrating keratoplasty for keratoconus: a prospective longitudinal evaluation

Abstract

Aims-To evaluate visual function and vision specific health status in patients undergoing penetrating keratoplasty for keratoconus. Methods-A prospective longitudinal study measuring logMAR visual acuity, contrast sensitivity, disability glare, binocular visual field, stereoacuity, and subjective visual function (VF-14) was conducted on 18 patients with keratoconus undergoing penetrating keratoplasty (PK), including six patients who had already had PK in the fellow eye. Data were collected preoperatively and at 3, 9, and 18 months after surgery. Results-Within 3 months of surgery there was significant improvement in aided visual acuity, contrast sensitivity, and stereoacuity (p<0.05); disability glare (p<0.05) no longer had a significant detrimental eVect on these variables. VF-14 score improved significantly throughout the postoperative period (p<0.05). There was significant correlation of the VF-14 score with aided visual acuity, binocular visual field, and stereoacuity. Postoperative astigmatism (<4D v >4D) did not aVect the VF-14 score significantly. Conclusions-There is substantial and rapid improvement in visual function and vision specific health status in keratoconic patients as a result of uncomplicated penetrating keratoplasty. (Br J Ophthalmol 2000;84:60-66) Keratoconus is the principal indication for penetrating keratoplasty in young adults and graft survival in this condition has been used as a yard stick against which to measure the outcome of corneal transplantation for other conditions. 1 Snellen visual acuity has long served as the primary visual function test of surgical success. However, some patients report limitations to vision despite a clear graft and good corrected visual acuity. Over the past two decades there has been mounting evidence that aspects of visual function other than acuity are impaired in those who have media opacities (corneal scarring and cataracts) and irregularities of the cornea. 2-5At the same time, detailed visual function assessments, which measure self rated disability, have been developed for patients with cataract and their response to surgery. [6][7][8][9] Very few such studies have been reported on patients who have undergone penetrating keratoplasty; most are retrospective and use a single point of time for assessment.5 8-11 The purpose of this study was to undertake a prospective longitudinal evaluation of visual function and vision specific health status in patients undergoing penetrating keratoplasty for keratoconus. MethodsKeratoconic patients undergoing penetrating keratoplasty from January 1996 to March 1996 under the care of two corneal surgeons (AT and AR) were invited to participate in this study. The diagnosis of keratoconus was based on slit lamp examination, computerised video keratotopography, and refraction. The study had approval from the local ethics committee and all subjects gave informed consent. Patients were eligible for the study if they were over the age of 16 years, willing to attend assessments in addition to the routine clin...

The impact of penetrating keratoplasty in patients with keratoconus using the VF-14 questionnaire

“…This surgical procedure is indicated for patients with keratoconus as it improves their visual function [14]. In a study by Brahma et al a significant improvement was recorded both in the BCVA and in the reported perception of ''contrast and dimensions'' three months after surgery.…”

Corneal Curvature after Penetrating Keratoplasty before and after Suture Removal: A Comparison between Keratoconus and Fuchs’ Dystrophy

“…Many studies support substantial and rapid improvement in visual acuity after PKP for KC [6,7,8,9], although up to 47% of eyes may require contact lenses for optimal vision [10]. However, little is known about the functional results after PKP for FUCHS [11].…”

Effectiveness of Corneal Topography Guided Suture Removal of the Patients with Penetrating Keratoplasty in Astigmatism Treatment

“…2,4 Buna rağmen postkeratoplasti astigmatizma bu hastalarda tatmin edici görme rehabilitasyonu elde etmede hala en büyük engeldir. 5 Birçok faktör postkeratoplasti astigmatizmanın tahmin edilemeyen ve değişken doğasına katkıda bulunmaktadır.…”