Eyeworld

93 EW INTERNATIONAL August 2017 bent rays coming through much of the cornea. Although the success of the device is largely reliant on good lighting and excludes peripheral vision, it offers highly satisfactory outcomes for patients with limited options. "The underlying concept of this intraocular pinhole device is perfect to address severe cases of irregular corneal astigmatism in pseudophakic eyes," Dr. Trindade said. EW Reference 1. Trindade C, et al. Novel pinhole intraocular implant for the treatment of irregular corneal astigmatism and severe light sensitivity after penetrating keratoplasty. JCRS Online Case Reports. 2015;3:4–7. Editors' note: Dr. Trindade has no financial interests related to his comments. Contact information Trindade: fernandotrindade@mac.com standard IOL implantation proce- dure, through a 2.2 mm clear corneal incision. The implant is designed for sulcus fixation, as a piggyback lens, either as a primary or secondary implant. Dr. Trindade prefers to use the black pinhole device implanta- tion as a secondary procedure so that he can gauge the results of device implantation. Examining intraocular struc- tures through a 1.3 mm aperture is limited. Thanks to its infrared trans- parency, however, the black pinhole implant allows examination of intraocular structures with the use of infrared transmittance testing with OCT (Spectralis, Heidelberg Engi- neering, Heidelberg, Germany). Like- wise, small slit lamp modifications such as the addition of an infrared LED light and an infrared converted camera make the visualization of the structures located behind the black implant possible. Dr. Trindade uses an infrared adapted slit lamp to examine the contours of the anterior capsulorhexis, the presence of opaci- fications on the posterior capsule, the size and shape of the posterior capsulotomy, and especially the relative position of the primary lens in the capsular bag. "The outcome of cataract sur- gery in cases of ocular trauma with the presence of severe corneal scars can be very disappointing to the pa- tient and the surgeon," Dr. Trindade said. "As a secondary implant, the black pinhole device is very interest- ing, especially for highly astigmatic cases. The advantage of using it as an additional device is that it can be easily explanted, if need be. Also, its dimensions are comparable to currently used sulcus IOLs, such as the Sulcoflex supplementary IOL [Rayner, East Sussex, U.K.], which is also a sulcus piggyback implant. "By comparison, the haptic of the XtraFocus type 93C pinhole implant is 250 µm, while that of the Sulcoflex is 350 µm, so it is much thinner than the Sulcoflex. The XtraFocus implant is well designed and effective. The concept behind this device is amazing," he said. Case studies Dr. Trindade recommended the use of the XtraFocus implant in the treatment of irregular corneal astigmatism and higher order aber- rations caused by radial keratotomy (RK), penetrating keratoplasty (PKP), or keratoconus. He described four different cases in which the pinhole device restored excellent uncorrected visual acuity. One case involved a one-eyed post-traumatic female pa- tient with severely irregular corneal astigmatism who was extremely un- satisfied with her post-surgical out- comes of 20/100 (J2) visual acuity. A black pinhole implant improved her uncorrected visual acuity dramati- cally, leaving the patient highly sat- isfied. In a second case, vision was re- stored in a patient with keratoconus who had a history of corneal ring implantation. A third case involved a patient with a history of RK and astigmatic keratotomy (AK) done 30 years prior to XtraFocus implanta- tion whose vision greatly improved with the pinhole implant. The fourth case scenario described a 44-year-old male with severe knife trauma to his left eye. The patient had a traumatic cataract, corneal lacerations, and partial iris loss. The primary treatment con- sisted of corneal suturing, cataract surgery, and IOL implantation. After the primary treatment, the patient complained of poor vision and disturbing, intrusive glare. He had a highly aberrated cornea and a large pupil. "This a wicked combination," Dr. Trindade said. Two months after the primary treatment, he implanted the pinhole device in the sulcus of the patient, which improved visual acuity from 20/80 (J3) to uncor- rected visual acuity of 20/25 (J1). The device also achieved complete resolution of glare, to the patient's great relief. "This device can be very helpful in severe cases of irregular corneal astigmatism, especially after nasty RKs with many incisions and very small optical zones," Dr. Trindade said. "The implant may also be applicable for presbyopia treatment, due to the extended depth of focus created by the pinhole effect." A published case study by in- vestigators at Dr. Trindade's institute that used the XtraFocus pinhole implant in a pseudophakic patient with decreased visual acuity due to irregular corneal astigmatism and intractable light sensitivity because of a fixed, dilated pupil after PKP showed similar device efficacy. The patient's best corrected visual acuity was 20/200 due to highly irregular astigmatism, and he had poor tolerance to the rigid contact lens. The pinhole device significantly improved visual acuity, allowing the patient to continue using the contact lens, and by reducing light entrance into the eye, it both minimized the impact of corneal aberration on the optical system and markedly decreased light sensitivity. 1 Pinhole concept The concept of stenopeic glasses, opaque eyeglasses with a series of pinhole perforations, is not a new idea. Each perforation allows a nar- row light beam into the eye, having the effect of reducing the width of the bundle of diverging rays. Even with a wide pupil, only the central part of the pupil receives light. De- creasing the aperture increases the depth of focus, which can result in a sharper image in eyes with refractive error. The XtraFocus operates along these lines, with the added effect of the opaque material blocking the The device is intended for sulcus implantation, in a piggyback configuration. With a larger diameter, thin and angulated haptics, the device is appropriate for sulcus implantation. Source (all): Fernando Trindade, MD, PhD

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