Demographic profile and visual rehabilitation of patients with keratoconus attending contact lens clinic at a tertiary eye care centre
Introduction
Keratoconus is a bilateral, asymmetric, chronic, progressive ectasia of the cornea characterized by steepening and distortion of the cornea, thinning of the apical cornea, and sometimes corneal scarring. Keratoconus affects people in their prime earning years and profoundly affects their lives. The majority of keratoconic eyes in Asian-Indian patients demonstrate the severe stage of the disease by the second decade [1]. Patients experience distorted vision that worsens with the disease progression. Although spectacles help in early stage, most patients require contact lenses for visual rehabilitation. Several rigid contact lens fitting sets available have their origin in one of the three fitting philosophies: apical clearance, three-point touch, and apical bearing [2], [3], [4]. With no accepted standardized protocols, the ‘three-point-touch’ approach is now the most widely accepted corneal lens fitting philosophy in clinical practice [3]. Custom-designed rigid lenses are the new options for patients with unacceptable fit [5], [6], [7]. The contact lenses fitting in keratoconus becomes difficult and less successful as the disease severity advances.
Most patients eventually undergo corneal transplantation in one or both eyes. Contact lens intolerance and unacceptable fit is the main indication for keratoplasty [11], [12]. Studies to date have reported >90% graft survival data between 5 and 12 years from the time of transplant [10], [11]. However reports of late recurrence of keratoconus have been described from 7 to 40 years after keratoplasty [10], [11], [12] with a mean latency of roughly 17 years [10]. Many of these cases are supported by histological confirmation [10], [13]. This seems important given the fact that most keratoconus patients receive transplants at a relatively young age. Therefore contact lenses seem important in delaying PK to a later age especially in India when keratoconus manifests at an earlier age as compared to the western countries [1], [9]. Furthermore visual rehabilitation is often slow and complicated [9]. Even keratoconus eyes treated with corneal transplants frequently need contact lenses for visual rehabilitation [25], [26], [27].
Section snippets
Aim
To evaluate the demographic profile of keratoconus patients in India and their functional outcomes and adaptability with various modalities of contact lens management in a tertiary eye care center.
Material and methods
The data of all patients with keratoconus attending the contact lens clinic of Dr Shroff's Charity Eye Hospital, Delhi between January 2007 and December 2007 was analyzed.
The patients were included in the study if they had unilateral or bilateral keratoconus as evidenced by clinical and slit lamp examination. The diagnostic criteria necessary for enrollment were corneal distortion in either eyes (as seen with keratometry or retinoscopy) and the presence of either Fleischer's ring, Vogt's
Results
The total number of new patients seen in contact lens clinic during the one-year study period was 856. The incidence of keratoconus in patients attending contact lens clinic was 8.9%. Seventy-seven patients with keratoconus (142 eyes) were examined during the study period. Out of the 77 patients, 49 (64%) were males and 28 (36%) were females (Fig. 2).
The age group ranged between 15 years and 52 years (median age 24 years).
Keratoconus grading based on keratometry was done (Table 1, Fig. 3).
Three
Statistical analysis
Difference 47.20% 95% CI 32.55–60.5% Chi-square 47.886 DF 1 Significance level P < 0.0001 Difference 28.60% 95% CI 19.26–38.6% Chi-square 40.171 DF 1 Significance level P < 0.0001 Difference 17.70% 95% CI −13.83% to 36.6% Chi-square 0.882 DF 1 Significance level P = 0.3477
Discussion
Keratoconus is a condition in which the cornea assumes a complex irregular curvature caused by central corneal thinning. The abnormal topography of the cornea in combination with central corneal scarring results in an impaired visual acuity [14]. Even in mild cases spectacles do not correct vision adequately [14]. Hence contact lenses remain the mainstay of treatment in these cases until intervention is required. Though the results of PK are very favorable in cases of keratoconus yet studies
Conclusion
In India keratoconus presents at an early age as compared to the western population and contact lenses offer a good modality to delay the requirement for penetrating keratoplasty. Newer philosophies for fitting contact lenses and newer materials can help in decreasing the contact lenses intolerance which still remains the major indication for undergoing penetrating keratoplasty.
References (26)
- et al.
Cinical management of keratoconus. A multicentric analysis
Ophthalmolgy
(1990) - et al.
Histologic evidence of recurrent keratoconus seven years after keratoplasty
Am J Ophthalmol
(1995) - et al.
Recurrent keratoconus after keratoplasty
Am J Ophthalmol
(1980) - et al.
Methods and findings to date
Contact Lens Anterior Eye
(2007) - et al.
Contact lens failure in keratoconus management
Ophthalmology
(1992) - et al.
The prognosis for keratoplasty in keratoconus
Ophthalmology
(1982) - et al.
Keratoconus in Asian eyes at a tertiary eye care facility
Clin Exp Optom
(2004) Keratoconus fittings: apical clearance or apical support?
Eye Contact Lens
(2004)- et al.
Standardized rigid contact lens fitting protocol for keratoconus
Optom Vis Sci
(1996) Use of contact lenses for management of keratoconus
Ophthalmol Clin North Am
(2003)