Referral patterns, treatment management and visual outcome in keratoconus

To determine the patterns of referral, the hospital-based management and the subjective degree of visual success achieved by keratoconics attending the Corneal Service at Sunderland Eye Infirmary, England, a specifically designed anonymous questionnaire was mailed to 160 keratoconus subjects.

The following responses were obtained from 97 (61%) respondents: mean age of first referral (22.88 +/- 8.36 years); gender (male:female ratio 3:1); source of initial referral (optometrists 90%); visual symptoms experienced before referral (46% complained of blurred/distorted vision); and the type of visual correction before referral (70% wore a refractive correction: 72% spectacles, 28% contact lenses). Initial post-referral treatment included bilateral contact lens fitting (65%), monocular contact lens correction (26%), penetrating keratoplasty (8%) and no intervention (1%). Two-thirds of subjects were presently wearing contact lenses (67%), with the mean period of successful lens wear being 8.26 +/- 7.92 years, and 31% had undergone penetrating keratoplasty (PK) since initial referral. A subjective evaluation of visual acuity with contact lenses was made by respondents using a visual analogue scale. The mean value was 86.86 +/- 15.25 (range 50-100 mm), with 50 mm representing moderate visual acuity. Of those who underwent PK the mean subjective evaluation of the change in post-operative vision compared with pre-operatively was 82.41 +/- 26.57 (range 1-100 mm), with 50 mm representing no visual change. The majority of subjects therefore noted a moderate to marked visual improvement following PK.

In this fairly young group of patients, predominantly male, the majority wore a refractive correction for approximately 10 years before referral to the Hospital Eye Service (HES). Most referrals were initiated by optometrists. On initial HES assessment the treatment for two-thirds was bilateral contact lens fitting; only a quarter were fitted monocularly. However, by the time of this study only a tenth retained monocular contact lens correction, with the mean length of time from diagnosis to bilateral contact lens wearing being approximately 5 1/2 years. The progressive nature of this disease is further evidenced by the large number of contact lens sets required by patients (approximately 5) and by the number of patients (n = 22) requiring PK, the mean length of time from diagnosis to corneal graft being approximately 8 1/2 years.