![Prevalence of
keratoconus in
Central India (0.0003%-
2.3%)
Gokhale NS. Epidemiology of keratoconus. Indian J
Ophthalmol 2013 [cited 2020 Feb 3];61:382-3.](https://image.slidesharecdn.com/indicationofrgplens-240430063016-37fed5ac/85/Indication-of-RGP-Lens-in-corneal-abnormalties-pptx-9-320.jpg)
Indication of RGP Lens in corneal abnormalties.pptx
- 1. INDICATION OF RGP LENS BY SATYENDRA SINGH SACHAN Asst Professor Rama University
- 6. Oxygen supply to the cornea Astigmatic correction regular irregular
- 7. KERATOCONUS Keratoconus is a benign, usually bilateral, non- inflammatory thinning and ectasia of the cornea, resulting in a high degree of irregular myopic astigmatism
- 9. Prevalence of keratoconus in Central India (0.0003%- 2.3%) Gokhale NS. Epidemiology of keratoconus. Indian J Ophthalmol 2013 [cited 2020 Feb 3];61:382-3.
- 10. KERATOCONUS CLEK DATA: CORNEA 44.37 D(SD 1.6 D) 0.50 D Cyl (SD 0.18 D) Axis 175属 Corneal Tilt: 0.38 (SD 0.11) Base-Apex line: 56属 - 236属 48.02 D (SD 3.88 D) 2.46 D Cyl (SD 0.99 D) Axis 26属 Corneal Tilt: 3.94 (SD 1.45) Base-Apex line: 69属 - 249属 Normals: 60 Eyes Keratoconics: 690 Eyes Raasch et al., 1998
- 12. KERATOCONUS CLASSIFICATION BY CORNEAL CURVATURE Mild: <45 D Moderate: 45 52 D Advanced: 52 65 D Severe: > 62 D
- 13. Symptoms Initially, asymptomatic Visual degradation reported at or after time of puberty Progresses slowly over 5 10 years Ghost image & photophobia
- 14. Sign Distorted keratometry mires Distorted photokeratoscopy rings Inferior steeping in videokeratoscopy maps Apical corneal thinning (stromal) Cone formation
- 18. KERATOGLOBUS It is a familial and hereditary bilateral congenital disorder characterized by thinning and hemispherical protrusion of the entire cornea. It is non- progressive and inherited as an autosomal recessive trait.
- 20. PENETRATING KERATOPLASTY Trephine Host button Donor button Double-armed suture Corneal button Diam.=Host+0.5 mm Sutures Corneal penetration > full thickness
- 24. BULLOUS KERATOPATHY (BK) POST-GRAFT Note: Avascular donor tissue One remaining suture
- 25. CORNEAL TOPOGRAPHY Incorrect placement of cardinal sutures Non-radial sutures Unequal suture tension(s) Pre-existing astigmatism in host or donor cornea Scar tissue in host cornea CAUSES OF ASTIGMATISM
- 27. GRAFT WITH 5 D CYL
- 28. RGPs (high Dk/t) when: patient wore RGPs previously postsurgical scarring present corneal irregularities present post-PK corneal ectasia Scleral lenses (gas permeable) in cases of: irregular corneas sensitive corneas after Bufidis et al., 2005
- 29. LENS SELECTION Rigid gas permeable lenses are the modality of choice following penetrating keratoplasty maximum correction of cylinder
- 30. RGP LENS Oxygen supply Correction of astigmatism Level of visual acuity
- 31. RGP LENS Correction of irregular astigmatism Provide high oxygen transmissibility Custom designs available
- 36. THANK YOU
Editor's Notes
- #17: According to Rabinowitz (1995, 1998), a diagnosis of keratoconus can be made if the patient has keratometry readings greater than 47.20 D, inferior corneal steepening of more than 1.20 D greater than the superior cornea, and skewing of the radial axis of astigmatism by more than 21 degrees.
- #23: 際際滷 18 shows a case of Bullous Keratopathy (BK) that developed after trauma to an eye that already had Fuchs dystrophy.
- #24: 際際滷 21 shows a quiet eye some time after surgery but before suture removal. In this case, there is also evidence of early crystalline lens changes.
- #25: 際際滷 19 shows the same patient after a PK. It is noteworthy that the donor tissue has remained avascular whereas the host tissue was/is quite vascularized. The reason for the one suture remaining is unknown.
- #29: Suggested lens types according to Bufidis et al. (2005) appear as slide 172.