title: Visual performance of rigid gas permeable contact lenses in patients with corneal opacity.
abstract: OBJECTIVE
  To evaluate the visual performance of rigid gas permeable (RGP) contact lenses in patients with nebular and nebulo-macular corneal opacity and correlate the improvement in visual acuity with other visual parameters.
  
  
  METHODS
  In a prospective study, visual performance of RGP contact lenses was evaluated in eyes with corneal opacity involving the pupillary area. The baseline visual acuity and other visual parameters with glasses were compared with those recorded with RGP contact lenses. The visual functions evaluated were visual acuity, contrast sensitivity, glare acuity, and mesopic vision. Binocular status with RGP contact lenses was assessed. All patients were followed up for 3 months.
  
  
  RESULTS
  Twenty-eight eyes (26 patients) with nebular or nebulo-macular corneal opacity were included in this study. All eyes (100%) achieved significantly better visual performance with RGP contact lenses than with glasses (P< 0.0020). Visual acuity of 6/9 or better was achieved in 50% of patients with RGP contact lenses compared to none with glasses. RGP contact lenses improved the visual acuity by 0.27 decimals over the baseline value with glasses, butthe improvement for mesopic vision and glare acuity was significantly lower at 0.15 and 0.06 decimals respectively. Similarly, contrast sensitivity did not improve to the same extent as visual acuity. Stereopsis was present only in patients with best corrected visual acuity of 6/9 or better with RGP lenses.
  
  
  CONCLUSIONS
  RGP contact lenses improved the visual acuity and other visual performance in patients with reduced vision due to nebular or nebulo-macular corneal opacity. However, contrast sensitivity, glare acuity, and mesopic vision did not improve to the same extent as visual acuity.
authors.affiliation: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi.
authors.forename: J S
authors.initials: JS
authors.lastname: Titiyal
authors.forename: A
authors.initials: A
authors.lastname: Das
authors.forename: V K
authors.initials: VK
authors.lastname: Dada
authors.forename: R
authors.initials: R
authors.lastname: Tandon
authors.forename: M
authors.initials: M
authors.lastname: Ray
authors.forename: R B
authors.initials: RB
authors.lastname: Vajpayee
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003261:Contact Lenses; D015350:Contrast Sensitivity; D003315:Cornea / Q000503:physiopathology*; D003318:Corneal Opacity / Q000503:physiopathology*; D005260:Female; D019466:Glare; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology*