Phakic iols

seminar

1. PHAKIC IOLs

2. History 1889 – clear lens extraction for correction of myopia – Fukala in austria / germany : FUKALA SURGERY, abandoned due to complications 1950 – correcting myopia by placing a concave lens into phakic eye 1988 – baikoff : anterior chamber angle fixated IOL 1991 – Artisan – iris claw lens

3. Options : Anterior chamber angle supported – B aikoff Anterior chamber iris fixated – Artisan / V erisyse Posterior chamber IOL – ICL and PRL

4. Indications Myopia > -8D and hyperopia > +5D Severe astigmatism – toric models may be needed When photoablation is contraindicated – corneal thickness < 500µ Residual bed after LASIK < 250µ. AC depth > 3.2 mm for ACIOLs and 2.8mm for PCIOLs Endothelial cell count >2200/mm2

5. Contraindications Low endothelial cell count and altered morphology Low AC depth Cataract Diabetic retinopathy Abnormal iris and angle Chronic uveitis

6. Patient selection Informed consent from patient Pupil size Corneal evaluation Anterior chamber evaluation Patient counselling

7. Preoperative diagnostics Unaided and BCVA N on contact confocal microscopy or specular microscopy - Endothelial cell count UBM or ASOCT – AC depth Anterior and posterior segment evaluation

8. Current models of iols

9. Two additional P-IOLs are currently in Phase 3 of clinical trials with a view to FDA approval : 1. The Veriflex - foldable P-IOL for the anterior chamber with iris fixation also known as Artiflex (OPHTEC). 2. The phakic AcrySof IOL for the anterior chamber with angle support The P-IOLs for anterior chamber and with angle Support are the AcrySof and the Kelman Duet

10. Implantable contact lens Available between -3.0 to -20.0 D and +1.50D to +20.0D ICL – STAAR model Single piece haptic design, made up of hydroxymethacrylate copolymer Optic – 5.5mm diameter Myopia - anterior concave and posterior concave Hyperopia – anterior convex/posterior concave Optical zone 4.5 to 5.5mm Sizing of posterior chamber PIOL – white to white measurement between 3 and 9’o clock hrs or by direct sulcus measurement

11. Video

12. Complications of posterior chamber phakic IOLs : 1. Cataract formation – most common 2. Pupillary block - Because of the PC phakic IOLs, the iris can be pushed forward and narrow the anterior chamber angle, so a pupillary block with acute glaucoma can appear - Prevented by PI 3. ↑ IOP and pigment dispersion 4. Decentration and rotation of IOL – diplopia, glare and pigment dispersion

13. Iris supported phakic IOL Artisan phakic lens is an iris-supported IOL The lens haptics attach to the midperipheral , immobile iris through a process called enclavation . In this technique, the surgeon draws small knuckles of peripheral iris into the pincer-like haptics. Thus the optic lies just anterior to the iris plane .

14. Patient selection : High myopia and high hyperopia Toric phakic IOLs for high myopia and hyperopia with astigmatism >18 yrs of age with stabilized myopia or hyperopia Sizing of iris fixated PIOL – one size fits all since it is fixed to midperipheral iris. Made up of PMMA with UV blocking Total length 8.5mm 5mm optic - -3 to -23.5D 6mm optic - -3 to -15.5D

15. Complications of Iris fixated AC IOL : 1. Endothelial cell loss 2. Chronic inflammation and uveitis 3 . Astigmatism – iris claw is not foldable it requires an incision. 4. Intraocular lens rotation – less common 5. Pigment dispersion and lens deposits – less common 6. Glaucoma – less common, PI is mandatory to prevent pupillary block 7. Cataract is less

16. Baikoffs foldable AC phakic IOL :

17. Complications Anterior chamber angle supported phakic IOLs : 1. Endothelial damage 2. Pigment dispersion and lens deposits 3. Chronic inflammation and uveitis 4. Pupil ovalization and iris retraction 5. Intraocular lens rotation 6. Surgically induced astigmatism 7. Glaucoma 8. Glare and halo

18. Advantages of phakic IOLS Potential to treat large range of myopic, hyperopic and astigmatic refractive error Allows the crystalline lens to retain its function preserving accomodation Removable and exchangeable Results are stable

19. Disadvantages Risk of intraocular procedure Nonfoldable models require large incisions that may result in postop astigmatism High ametropic patients may require additional photorefractive surgery Endothelial cell loss and cataract formation Pupil ovalization , chronic uveitis, pupillary block, pigment dispersion

20. Refractive outcome of phakic iols Refractive outcomes are very good Phakic IOL surgery is also reasonably safe . In this challenging set of eyes with high refractive errors, the vast majority of patients do very well with a significant portion gaining lines of BCVA

21. Myopia -1 to -10 D Hyperopic +1 to +3D Astigmatism up to 3D corneal thickness atleast 250µ of posterior stroma should be preserved T otal corneal thickness atleast 410µ after LASIK Myopia -10 to -22D Hyperopia +4 to +10D Astigmatism upto 3D corrected with toric IOLs corrects the full range of refractive errors N ot associated with the limitations of LASIK LASIK PHAKIC IOLS

22. Bioptics Two different procedures in two different planes of eye 1 st procedure – intraocular 2 nd procedure – LASIK, LASEK or PRK Indicated in patients with refractive errors that are suboptimally treated with a single procedure Eg : high myopes , high hyperopes or with significant astigmatism

23. Future of phakic iols Artisan phakic toric intraocular lens : correction of regular astigmatism in combination with myopia or hyperopia Baush and lomb – testing a foldable version of NuVita AC angle fixated PIOL Artiflex – foldable version of iris fixated AC PIOL

24. Thinoptx – ultrathin intraocular lenses : thickness ranging from 30 to 350 microns. Ultrathin, rollable model designed using nanoscale precision technology Even in large diopters lens remains thin

25. Smart lens : made of a thermodynamic, hydrophobic acrylic material. At body temperature, the biconvex lens is 9.5 mm in diameter and from 2 to 4 mm thick The lens is highly flexible and completely elastic , returning to its original shape when deforming forces are released

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