To evaluate the demographic profile, management and functional outcomes of patients with
keratoconus attending the
contact lens clinic of a tertiary ophthalmic referral centre over a one year period.
METHODS: A retrospective cohort analysis was conducted by reviewing the computerised hospital records of 130 patients attending The Western Eye Hospital
contact lens department over the period 1st Jan 1999 to 31st Dec 1999. Data on age, gender, referral pattern, visual acuity,
contact lens fitting, degree of visual success, and some information on
penetrating keratoplasty were obtained.
RESULTS: 16.4% of all patients attending the
Contact Lens clinic had
keratoconus. The mean age at referral was 28.6 years and the mean age of
keratoconus during the study period was 34.9 years. There was a predominance of male patients. Optometrists formed 72.2% of the referrals, and had prescribed some form of refractive correction in 70% of patients (two-thirds
contact lenses) prior to hospital assessment. Of the 130 patients seen in the department during the study period, the post-referral management included bilateral
contact lens fitting for 102 patients (78.5%), monocular
contact lens fitting for 24 patients (18.5%) and no intervention in four patients (3%). The types of
contact lenses used included
PMMA lenses (2.7%), rigid gas permeable
lenses (96.1%) of the spherical, elliptical and special cone lens designs, Keratosoft or Softperm
lenses (0.8%) and scleral
lenses (0.4%). Eleven eyes of eight patients had received
penetrating keratoplasty (PK) prior to hospital assessment, of whom seven eyes needed post-surgical
contact lens fitting. The main reasons for PK were
contact lens intolerance (83%), frequent
contact lens displacement (8.5%) and unsatisfactory visual acuity despite good
contact lens fit (8.5%). Sixty-five per cent of patients were able to wear their
contact lenses for more than 12 hours a day. With
contact lens wear, 87% of patients had a visual acuity of 6/9 or better and 59% of eyes had improved visual acuity of 0.6 logMAR or more.
CONCLUSION: Optometrists were the main source of referral for
keratoconus patients to the Hospital Eye Service (HES). The mean age at referral was 28.6 years, with a predominance of male patients. Blurred vision formed the main presenting visual symptom on initial hospital assessment; subsequently, more than two-thirds of patients required bilateral
contact lenses. Rigid gas permeable
contact lenses remain the mainstay treatment for advanced
keratoconus, with various designs enabling a large proportion of patients to attain improved visual acuity.