PROBLEMS OF APHAKIA IOL Maj M Ahsan Mukhtar

PROBLEMS OF APHAKIA & IOL Maj M. Ahsan Mukhtar FCPS, FRCS (Glasg) CLASSIFIED EYE SPECIALIST REGISTRAR VITREO-RETINAL SURGERY

OBJECTIVES § Enlist common problems of aphkaia § Briefly describe the mechanism / physics of these problems § Know basics of intraocular lenses

PROBLEMS OF APHAKIA § § § § Relative spectacle magnification (RSM) Anisometropia in unilateral aphakia Aberrations Heavy lenses (glasses) Visual field limitation Loss of ultra-violet protection Other problems § § Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia

RELATIVE SPECTACLE MAGNIFICATION n n The ratio between the corrected and uncorrected image size Image is 33% larger in corrected aphakia Patient may misjudge distances Actual VA of an Aphakic reading 6/9 is approx 6/12

RELATIVE MAGNIFICATION AND IMAGE SIZE SOLUTION n n Intra-ocular lens Contact lens Isiekonic lens Corneal procedures

PROBLEMS OF APHAKIA § § § § Relative spectacle magnification (RSM) Anisometropia in unilateral aphakia Aberrations Heavy lenses (glasses) Visual field limitation Loss of ultra-violet protection Other problems § § Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia

ABERRATIONS IMAGE DISTORTION troublesome to the newly aphakic patients Straight lines appears curved except when viewed through a very small axial zone of lens

ABERRATIONS RING SCOTOMA The prismatic power of the more peripheral parts of a spherical lens

ABERRATIONS JACK-IN-THE-BOX The direction of the scotoma changes as the patient moves his eyes, and objects may appear out of the scotoma or disappear into it. SOLUTION Tell the patient to move his head instead of moving eyes while wearing aphakic glasses

PROBLEMS OF APHAKIA § § § § Relative spectacle magnification (RSM) Anisometropia in unilateral aphakia Aberrations Heavy lenses (glasses) Visual field limitation Loss of ultra-violet protection Other problems § § Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia

HEAVY GLASS LENSES n Use plastic lenses

PROBLEMS OF APHAKIA § § § § Relative spectacle magnification (RSM) Anisometropia in unilateral aphakia Aberrations Heavy lenses (glasses) Visual field limitation Loss of ultra-violet protection Other problems § § Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia

VISUAL FIELD LIMITATION n SOLUTION Ask Patient to move head instead of moving eyes while wearing aphakic glasses

PROBLEMS OF APHAKIA § § § § Relative spectacle magnification (RSM) Anisometropia in unilateral aphakia Aberrations Heavy lenses (glasses) Visual field limitation Loss of ultra-violet protection Other problems § § Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia

LOSS OF ULTRA-VIOLET PROTECTION n SOLUTION n Intra-ocular lens with UV protection n Glasses with UV protection

PROBLEMS OF APHAKIA § § § § Relative spectacle magnification (RSM) Anisometropia in unilateral aphakia Aberrations Heavy lenses (glasses) Visual field limitation Loss of ultra-violet protection Other problems § § Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia

OTHER PROBLEMS DUE TO APHAKIA n n Cystoid Macular edema Retinal Detachment Increase In Proliferative Diabetic Retinopathy Amblyopia in children with unilateral aphakia n Occlusion therapy n IOL n Contact lenses

INTRA OCULAR LENSES

$INTRA OCULAR LENSES n The optic (the central refracting element) n The heptics$

INTRA OCULAR LENSES n The optic (the central refracting element) n The heptics

IOL MATERIAL Optic n n n Polymethylmethacrylate (PMMA) Silicon Acrylic (hydrophillic and hydrophobic) Hydrogel Heptics n n n Polypropylene (3 piece) Same material as optics (1 piece)

IOL DESIGN

TYPES OF IOL AC IOL Iris claw Lens PC IOL

IOL TYPES n Monofocal IOL n Multifocal IOL n Toric n Accomodative

PLACEMENT OF IOL IN EYE n The posterior chamber (PC IOL) n capsular bag n Sulcus n The anterior chamber (AC IOL) n Iris / pupil supported n Angle supported

AC-IOL

PC IOL n PC IOL in Capsular bag

RIGID VS FOLDABLE IOL’S n n Rigid n PMMA n One piece to facilitate maximal stability and fixation Foldable n Silicone IOLs: have lower rates of posterior capsular opacification than PMMA IOLs n Acrylic IOLs n Hydrogel IOLs: have higher water content n Collamer IOLs : are a mixture of collagen and hydrogel (newly developed)

ADVANTAGES OF IOLs n All problems of aphakia ------ gone n Broader field of view n Lesser problem of image magnification n Binocularity is maintained

DISADVANTAGES OF IOLS n Problems of accommodation n Chances of dislocation into the vitreous n UGH syndrome with AC-IOL n Endothelial decompensation

THANK YOU