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Cataract formation after posterior chamber phakic intraocular lens implantation

Abstract Posterior chamber phakic intraocular lens (PCP IOL) implantation is an emerging refractive procedure. We report a case of cataract formation e months after uneventful implantation of a Staar PCP IOL to correct high myopia. Visual recovery was achieved after explantation of the phakic IOL and phacoemulsif!cation with implantation of a foldable IOL through the same unenlarged self‐sealing corneal incision.

Spherical Aberration and Contrast Sensitivity in Eyes Implanted with Aspheric and Spherical Intraocular Lenses: A Comparative Study

PURPOSE To determine whether implantation of an intraocular lens (IOL) with a modified anterior aspheric surface results in reduced spherical aberration and improved contrast sensitivity after cataract surgery. DESIGN Prospective, comparative, interventional case series. METHODS In an intraindividual randomized prospective study of 25 patients with bilateral cataract, an IOL with a modified anterior surface (Tecnis Z9001; Advanced Medical Optics, Santa Ana, California, USA; group 1) was compared with biconvex lens with spherical surfaces (ClariFlex; Advanced Medical Optics; group 2). Ocular aberrations for a 5.0-mm pupil and 6.0-mm pupil were measured with Hartmann-Shack aberrometer. Quality of vision was measured by visual acuity and contrast sensitivity under mesopic and photopic conditions. All patients were followed up for three months. RESULTS No statistically significant difference in postoperative uncorrected and best-corrected distance vision acuity after a follow-up of three months existed between the groups. Postoperative contrast sensitivity testing revealed significant differences between the groups under photopic and mesopic conditions. These differences reached statistical significance under photopic conditions at three spatial frequencies and under mesopic conditions at all spatial frequencies. When analyzing higher-order aberrations, the difference between the groups was statistically significant at the 5.00-mm and 6.00-mm pupil diameters, with the group 1 inducing less higher-order aberration and also less spherical aberration compared with group 2. CONCLUSIONS Results show the Tecnis Z9001 IOL with a modified anterior aspheric surface induced significantly less higher-order aberration and spherical aberration compared with the ClariFlex IOL. Contrast sensitivity revealed better values under photopic and mesopic conditions with the Tecnis Z9001 IOL.

Ocular aberrations and contrast sensitivity after cataract surgery with AcrySof IQ intraocular lens implantation Clinical comparative study

PURPOSE: To determine whether implantation of an intraocular lens (IOL) with a modified posterior aspherical surface (AcrySof IQ, Alcon Surgical Laboratories) results in reduced ocular aberrations (spherical aberration) and improved contrast sensitivity after cataract surgery. SETTING: Brasilia Ophthalmologic Hospital, Brasilia, and Sao Geraldo Eye Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil. METHODS: In an intraindividual randomized prospective study of 25 patients with bilateral cataract, an IOL with a modified posterior surface (AcrySof IQ) was compared with a biconvex IOL with spherical surfaces (AcrySof Natural, Alcon). Ocular aberrations with a 5.0 mm and 6.0 mm pupil were measured with a Hartmann‐Shack aberrometer. Quality of vision was measured by visual acuity and contrast sensitivity under mesopic and photopic conditions. All patients were followed for 3 months. RESULTS: There were no statistically significant differences between eyes in postoperative uncorrected and best corrected distance visual acuities after a follow‐up of 1 month and 3 months. Postoperatively, there was a statistically significant between‐group difference in contrast sensitivity under photopic conditions without glare at 18 cycles per degree (cpd) (P = .04) and under mesopic conditions without glare at all spatial frequencies (3 cpd, 6 cpd, 12 cpd, and 18 cpd; P = .03, P = .009, P = .003, and P = .003, respectively) and with glare at 3 cpd and 6 cpd (P = .001 and P = .02, respectively). The difference in higher‐order aberration (HOA) values between groups was statistically significant with a 5.0 mm and 6.0 mm pupil, with the AcrySof IQ IOL inducing less HOA than the AcrySof Natural IOL. Eyes with an AcrySof IQ IOL also had statistically significant less spherical aberration than eyes with an AcrySof Natural IOL with both pupil diameters (P<.001). CONCLUSIONS: The AcrySof IQ IOL with a modified posterior surface induced significantly less HOA and spherical aberration than the AcrySof Natural IOL. Contrast sensitivity was better under mesopic conditions with the AcrySof IQ IOL.

Ultrasound biomicroscopic imaging of posterior chamber phakic intraocular lens

BACKGROUND Phakic intraocular lens (IOL) implantation represents a major technique for the correction of high myopia. The STAAR collamer posterior chamber phakic IOL--trade named Implantable Contact Lens--is an emerging technology in refractive surgery. We studied the relative position of the posterior chamber phakic IOL using ultrasound biomicroscopy. METHODS The posterior chamber phakic intraocular lens was inserted in 9 eyes of 8 patients with high myopia. Ultrasound biomicroscopy was performed before and after implantation of the phakic IOL to assess its relative position in the anterior segment of the eye. The parameters measured and compared were anterior chamber depth, angle opening distance 500 microns from the scleral spur, iris-crystalline lens contact distance, iris-IOL contact distance, and IOL-crystalline lens distance. RESULTS Ultrasound biomicroscopy showed contact between the iris and the IOL in all eyes and between the IOL and the crystalline lens in 8 eyes. Reduction in the anterior chamber depth and localized narrowing of the angle opening were observed in all eyes. CONCLUSION IOL-iris touch, IOL-crystalline lens touch, and anterior chamber shallowing raise concerns of pigmentary dispersion, cataractogenesis, and narrow angle glaucoma following posterior chamber phakic intraocular lens implantation. Clinical data are needed to determine if these problems occur.

Benefit of against-the-rule astigmatism to uncorrected near acuity

Purpose: To determine whether with‐the‐rule (WTR) or against‐the‐rule (ATR) astigmatism gives a better visual outcome after cataract and intraocular lens (IOL) implantation surgery by comparing the uncorrected distance and near visual acuities in eyes with low, simple, myopic residual astigmatism. Setting: S. Geraldo Eye Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil. Methods: Two groups of 10 eyes each, one with WTR and the other with ATR simple, myopic astigmatism, were studied after uneventful cataract and IOL implantation surgery. All patients had an uncorrected distance visual acuity of 20/40 or better. The negative cylinder ranged from 1.00 to 1.50 diopters (D). The uncorrected distance and near visual acuities of the two groups were compared. Results: There was no statistically significant between‐group difference in uncorrected distance visual acuity. However, for uncorrected near, the difference between groups was highly statistically significant (P < .001). Patients with ATR astigmatism had much better uncorrected near acuity than those with WTR astigmatism. Conclusion: In pseudophakia, low, simple, ATR myopic astigmatism is better than WTR astigmatism because it provides superior uncorrected near visual acuity.

Fisiologia da acomodação e presbiopia

Presbyopia is one of the earliest universal signs of aging and the basic pathophysiology involved in its development has been a matter of controversy for centuries. This article discusses many aspects of presbyopia by reviewing the literature on the multitude of age-related changes that occur in the eye.Presbyopia is one of the earliest universal signs of aging and the basic pathophysiology involved in its development has been a matter of controversy for centuries. This article discusses many aspects of presbyopia by reviewing the literature on the multitude of age-related changes that occur in the eye.

Outcomes of radiofrequency in advanced keratoconus

PURPOSE: To evaluate the use of radiofrequency energy to correct advanced keratoconus. SETTING: Universidade Federal de Minas Gerais, Belo Horizonte, and Universidade de Ciências da Saúde de Alagoas, Maceió, Brazil. METHODS: In this prospective comparative study, radiofrequency was applied to 25 eyes of 21 consecutive patients. One group comprised patients with a K‐reading between 54.0 diopters (D) and 58.0 D; 8 thermal spots were placed at the 4.0 mm optical zone. The other group comprised patients with a K‐reading greater than 58.0 D; 16 spots were applied at the 4.0 mm and 5.0 mm optical zones. The minimum follow‐up was 18 months in all patients. Differences between preoperative and postoperative uncorrected visual acuity, best spectacle‐corrected visual acuity (BSCVA), manifest refraction, and K‐readings were clinically and statistically evaluated. RESULTS: At end of the 18‐month follow‐up, the mean BSCVA in the 8‐spot group improved from 20/100 (0.71 ± 0.25 logMAR) preoperatively to 20/40 (0.32 ± 0.11 logMAR) and in the 16‐spot group, from 20/200 (1.03 ± 0.30 logMAR) to 20/60 (0.62 ± 0.22 logMAR). The mean manifest refractive spherical equivalent (MRSE) improved from −7.70 D ± 5.20 (SD) preoperatively to −6.82 ± 4.41 D after 18 months in the 8‐spot group and from −11.33 ± 6.70 to −8.38 ± 5.12 D, respectively, in the 16‐spot group. The mean best contact lens–corrected visual acuity was 20/30 (0.18 ± 0.24 logMAR) in the 8‐spot group and 20/40 (0.31 ± 0.19 logMAR) in the 16‐spot group. A dense corneal scar was seen in 1 patient in the 16‐spot group at the 6‐month follow‐up. CONCLUSIONS: Radiofrequency appeared safe for the treatment of advanced keratoconus. Contact lens fitting was stable in all cases.

Exchange of a posterior chamber phakic intraocular lens in a highly myopic eye

A 38-year-old woman had posterior chamber phakic intraocular lens (IOL) implantation as a secondary refractive procedure to correct residual refraction (20/50 with -16.50 -1.50 x 80) in May 1998, 3 years after intrastromal corneal ring segment surgery for high myopia (-30.00 diopters). Ultrasound biomicroscopy revealed an oversized lens, leading to malpositioning. Moreover, the patient remained undercorrected (20/40 with -5.25 -0.75 x 120). Ten months later, the phakic IOL was uneventfully exchanged for a shorter one with the correct dioptric power. It was well placed in the posterior chamber. The patients visual acuity was 20/30 with -2.25 -0.75 x 145, very close to the refraction in the fellow aphakic eye (20/30 with -2.50 -0.75 x 75). Patient satisfaction with the final visual outcome was high. Accurate ciliary sulcus measurement is critical for proper phakic IOL sizing.

Haptic-induced recurrent vitreous hemorrhage and increased intraocular pressure with a hydrophobic acrylic intraocular lens

A 72-year-old white woman had phacoemulsification with implantation of a hydrophobic acrylic single-piece intraocular lens (IOL) (AcrySof SA60AT, Alcon) in the right eye. A few weeks after surgery, she reported episodes of blurred vision due to recurrent vitreous hemorrhage, which got worse over time. The increased intraocular pressure (IOP) noted after surgery was controlled with minimal topical treatment. The superior haptic of the hydrophobic acrylic IOL was displaced from the capsular bag over the anterior capsule. The displaced haptic was amputated 16 months after cataract surgery. The episodes of blurred vision vanished completely, and the IOP returned to normal levels without therapy.

Transient cataract and hypermetropization in diabetes mellitus: case report

A 13-year-old male patient with a recent history of hyperglycemia developed an acute bilateral posterior subcapsular cataract, consisting of fine feathery streak-like opacities. On examination, his uncorrected visual acuity was 20/50 and J4 at near in both eyes. Under cycloplegia, a moderate hypermetropic refraction was noted in both eyes. He was diagnosed with acute posterior subcapsular cataract secondary to diabetes mellitus. Two weeks after resolution of the hyperglycemic state, the bilateral feathery streak-like posterior subcapsular opacities regressed completely, hypermetropic refraction decreased and uncorrected visual acuity improved to 20/20 and J1 in both eyes.