Optical rehabilitation or Correction of Aphakia
Download as PPT, PDF•13 likes•4,270 views
The document discusses aphakia, which is the absence of the crystalline lens from the eye. This can be caused by congenital issues, lens absorption, trauma, or surgical removal of the lens. Symptoms include defective vision and visual distortions. For aphakic patients to see clearly, they require optical rehabilitation like spectacles, contact lenses, or intraocular lenses. The document then focuses on the types, history, and surgical techniques for implanting different kinds of intraocular lenses.
Optical rehabilitation or Correction of Aphakia
- 2. Removal of the cataractous lens renders the patient Aphakic. Aphakia- Aphakia literally means absence of crystalline lens from the eye.
- 3. causes Congenital absence of lens. Due to absorption of lens matter. Traumatic extrusion of lens. Posterior dislocation of lens. Surgical aphakia occuring after removal of lens.
- 4. symptoms Defective vision. Erythropsia & cynopsia(i.e.seeing red & blue images)
- 5. sign Anterior chamber is deep. Iridodonesis. Pupil is jet black. Retinoscopy reveals high hypermetropia.
- 6. For the pt. to be able to see clearly some form of optical rehabilitation must be provided. This may be in the form of 1.Spectacles 2.Contact lenses 3.Intraocular lens
- 7. Comfort & Optical Aniseikonia convenience aberration spectacle •Heavy •Visual •Magnification •Cosmetically distortion, pin of 20-30% so poor cushion effect produces because of diplopia central magnification Contact •Insertion & nil •Magnification lens removal about cumbersome 8%,tolarable Iol Comfertable nil •Magnification in every way 1- 2%,negligible
- 8. INTRAOCULAR LENS The central part overlying the optic axis is called Optic. Peripheral arms used for placement & stabilization are the Haptic.
- 9. History Intraocular lens implant history had its beginning on Nov.29,1949 when Harold Ridley, a British ophthalmologist performed his 1st case.
- 10. Types of IOLs Anterior chamber IOL Iris-supported lenses Posterior chamber lenses
- 11. Anterior chamber IOL Lie in front of iris & supported in the angle of anterior chamber. ACIOL inserted after ICCE or ECCE. It is not so popular due to comparatively higher incidence of bullous keratopathy. Kelman multiflex type of ACIOL is used.
- 12. Iris supported lenses These lenses are fixed on the iris with the help of sutures, loops or claws. These lenses also have a high incidence of postoperative complication. E.g. Singh & Worst’s iris claw lens.
- 13. Posterior chamber lenses PCIOLs rest entierly behind the iris. This may be supported by the ciliary sulcus or the capsular bag, recent trend is towards in the bag fixation. Depending on material of manufacturing,types of PCIOLs are available
- 14. Rigid IOLs- made entirely from PMMA. Foldable IOLs- use after Phacoemulsification are made of silicon, acrylic, hydrogel & collamer. Rollable IOLs- It is after phakonit technique.made of hydrogel.
- 15. Calculatio of IOL power- Most common method is SRK formula by regression formula. P=A-2.5L-0.9K P=power of IOL A=constant L=axial length of eyeball.
- 16. For long eyeball some adjustment is made in the formula by taking new constant A1.
- 17. A1(new const.) Axial lenth of eye A1 3 <20mm A1 2 20 to <21mm A1 1 21 to <22mm A 22 to 24.5 mm A-0.5 >24.5mm
- 18. Surgical technique of ACIOL implantation Can be carried out after ICCE & ECCE. After lens extraction, the pupil is constricted by injecting miotics into A.C. A.C. is filled with 2% methylcellulose or 1% sodium hyaluronate. IOL,held by a Forceps gently slid into A.C.
- 19. Inferior haptic is pushed in the inferior angle at 6o’ clock position & upper haptic is pushed to engage in the upper angle.
- 20. Technique of posterior chamber IOL implantation Implantation of rigid IOL- It implanted after ECCE. Capsular bag & A.C. is filled with 2% methylcellulose or 1%sodium hyaluronate. IOL,hold by a Forceps.
- 21. Inferior haptic is pushed in the inferior angle at 6o’ clock position The superior haptic is grasped by tip, & is gently pushed down & then released to slide in the upper part of the capsular bag behind the iris. The IOL is then dilated into the horizontal position.
- 22. Implantation of foldable IOLs is made either with the help of holder-folder forceps or the foldable IOLs injector.
- 23. References Parsons’ diseases of the eye.