Demographic profile and visual rehabilitation of patients with keratoconus attending contact lens clinic at a tertiary eye care centre

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Abstract

Objective

To assess demographic profile and functional outcomes of patients with keratoconus attending contact lens clinic at a tertiary eye care centre.

Materials and methods

Retrospective analysis of 77 patients (142 eyes) diagnosed with keratoconus attending contact lens clinic at Dr Shroff's Charity Eye Hospital, New Delhi, from January 2008 to December 2008 was done. Data on age, gender, slit lamp examination, keratometry, topography, visual acuity with log MAR conversion, degree of visual success, type of contact lens and fitting characteristics were obtained.

Results

One hundred and forty-two eyes of 77 patients were analyzed of which 49 (63%) were males and 28 (37%) were females; their median age was 24 years (15–36 years). Keratoconus reading based on keratometry was done. Twenty eyes (14.4%) were diagnosed to have mild keratoconus, 51 eyes (36.7%) had moderate, 45(32.4%) had advanced and 23 eyes (16.6%) had severe keratoconus. 113 eyes (79.5%) were visually rehabilitated with RGP lenses while 29 eyes (20.4%) fitted best with Rose-K lenses and in 1 patient (0.1%) Boston scleral lens was given in both eyes. With contact lens wear, visual acuity improved to 6/9 (0.18 log MAR) or better in 91% (115 eyes) and 141 (99%) eyes improved to 6/18 (0.48 log MAR) or better.

Conclusion

We found that in India keratoconus presents at an early age as compared to the western population. 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.

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

Comparison of BCVA 6/9 or more between contact lens and glasses.

Difference47.20%
95% CI32.55–60.5%
Chi-square47.886
DF1
Significance levelP < 0.0001

Comparison of BCVA 6/18 or more between contact lens and glasses.

Difference28.60%
95% CI19.26–38.6%
Chi-square40.171
DF1
Significance levelP < 0.0001

Comparison of BCVA 6/12−6/18 between contact lens and glasses.

Difference17.70%
95% CI−13.83% to 36.6%
Chi-square0.882
DF1
Significance levelP = 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.

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