Prediction of the small aperture intraocular lens on visual acuity in patients with keratoconus.

PURPOSE: To investigate the impact of corneal higher-order aberrations (HOAs) on predicted corrected distance visual acuity (CDVA) in patients with keratoconus at varying simulated pupil apertures. SETTING: Ophthalmology clinics, Medical University of South Carolina, USA. DESIGN: Retrospective chart review study. METHODS: 56 eyes with keratoconus were examined using Scheimpflug tomography during routine examinations prior to medical intervention. The severity of keratoconus was graded using the Amsler-Krumeich classification. Zernike analysis was used to obtain corneal aberrations using simulated pupil diameters of 6-, 4-, and 2 mm. These data were extrapolated to obtain the total RMS HOAs for a 1.6 mm simulated pupil to evaluate the potential effect of a small aperture intraocular lens. Correlation analysis was used to study the impact and relative contributions of HOAs on CDVA. Convolution of HOAs from OPD-Scan III (NIDEK) provided a clinical method to predict CDVA with different simulated pupil sizes in corneas with irregular astigmatism. RESULTS: There were statistically significant positive correlations between photopic CDVA and the magnitude of total and individual (coma, spherical aberration and trefoil) HOAs in this cohort of keratoconus subjects. A keratoconus case with the small aperture IOL confirms the improvement in vision due to the pinhole effect. CONCLUSIONS: The small aperture IOL is expected to markedly reduce aberrations in keratoconus patients up to Amsler-Krumeich class 4 severity to levels consistent with the levels seen in healthy patients. Convolution of corneal HO aberrations with the ETDRS chart provides a useful simulation of the impact of pinhole optics in aberrated eyes.

Scheimpflug-Derived Corneal Lower and Higher Order Aberrations Post Intrastromal Corneal Ring Segments for Keratoconus.

Intrastromal corneal ring segments (ICRS) improve corneal topographic symmetry and reduce corneal aberrations through regularization of the corneal surface, thereby functioning as a viable surgical intervention for patients with keratoconus. This study aims to evaluate changes in lower- (LOAs) and higher-order aberrations (HOAs) amongst varying pupil sizes pre- and post- ICRS implantation in keratoconus patients. We specifically investigate the impact of pupil size on total corneal HOAs up to the 6th order. Twenty-one eyes that underwent ICRS implantation were included in this prospective interventional study. LOAs and HOAs measurements at the 6 mm, 4 mm, and 2 mm pupil diameters were collected preoperatively and at 6 months postoperatively using the Zernicke analysis function on a Scheimpflug device. ICRS implantation demonstrated a statistically significant effect in vertical coma with a −0.23 reduction (p = 0.015) for a 4 mm pupil size and a −1.384 reduction (p < 0.001) for 6 mm, with no significant effect at 2 mm. Horizontal coma, astigmatism 0°, astigmatism 45°, trefoil 5th order 30°, and RMS HOA demonstrated significant reductions at 4 mm or 6 mm pupil sizes but not at 2 mm. Our analysis demonstrates a favorable effect of ICRS implantation on larger pupil sizes, suggesting the importance of pupil size as it correlates with HOAs reduction.

Anterior segment reconstruction due to cosmetic iris implants placed in the anterior chamber.

A 27-year-old woman had BrightOcular iris implants placed for cosmetic purposes that changed eye color from brown to blue bilaterally. Of note, BrightOcular implants are not approved by the U.S. Food and Drug Administration (FDA) for use in the United States and have been associated with severe ocular complications. In keeping with their design, they were placed in the anterior chamber (AC) in both eyes of this patient; surgery was performed outside the United States. As has been described previously and tragically in other cases, she developed chronic inflammation, intolerable glare, angle-closure glaucoma, corneal edema, and cataracts in both eyes. For medically unmanageable elevated intraocular pressure (IOP), she underwent diode laser cyclophotocoagulation (CPC) in both eyes, and eventually, an Ahmed tube shunt (New World Medical, Inc.) was placed in the right eye. Although she was advised and urged to have the iris implants removed, despite her ocular issues, she refused removal until intolerable glare and reduced vision ensued. Ultimately, both iris implants were extracted 5 years after implantation by a U.S. surgeon; the procedures resulted in corneal decompensation and progressive cataract development. Subsequent penetrating keratoplasty (PKP) was performed for the right eye, but it failed because of contact with the glaucoma tube shunt. She sought additional consultation and presented with the following findings: corrected distance visual acuity was 20/400 in the right eye and 20/40 in the left eye, IOP of 18 mm Hg in the right eye and 16 mm Hg in the left eye, pupils were nonreactive and fixed, and extraocular muscles and central visual field were normal. Pachymetry was 868 µm in the right eye and 653 µm in the left eye. Anterior segment examination in the right eye revealed a failed corneal graft with 3+ edema, peripheral anterior synechiae (PAS) for 360 degrees, shallow AC, Ahmed tube shunt at the 11 o'clock position and remnant iris adherent to the graft-host junction for 270 degrees, 3+ posterior subcapsular cataract, and 2+ cortical cataract (Figure 1JOURNAL/jcrs/04.03/02158034-202208000-00024/figure1/v/2022-08-01T210317Z/r/image-tiff). The sclera revealed multiple circular and circumferential atrophic blue spots consistent with high-energy transscleral CPC (Figure 2JOURNAL/jcrs/04.03/02158034-202208000-00024/figure2/v/2022-08-01T210317Z/r/image-tiff). In the left eye, she had remnant fixed dilated iris for 270 degrees, missing iris superiorly for 3 clock hours, an adequate AC, and 2+ cortical cataract (Figure 3JOURNAL/jcrs/04.03/02158034-202208000-00024/figure3/v/2022-08-01T210317Z/r/image-tiff). Posterior segment examination revealed a 0.5 cup-to-disc ratio in both eyes with normal vessels, macula, vitreous, and retinal periphery, bilaterally. Given this constellation of findings, how would you proceed?

Possible Sampling Error in Corneal Specular Microscopy: Can Central Endothelial Data Generated by Specular Microscope Represent the Real Clinical Condition of the Whole Cornea?

PURPOSE: To estimate the minimum number of cells required to obtain reliable data in a specular microscope, which could possibly represent the real clinical condition of the corneal endothelium. METHODS: A cross-sectional study of 122 eyes of 61 individuals submitted to noncontact specular microscope was conducted. Data generated by the manufacturer's software were uploaded to specific statistical software for sampling relative error calculation. When relative error was above 5%, new images were acquired and more cells counted until the desired relative error was reached. Data analyzed in this study for the desired relative error were number of cells marked by the examiner for each eye (marked cells), number of cells used for data analysis (analyzed cells), endothelial area used for analysis, sampling error, and absolute number of images used for each eye. RESULTS: The average number of marked cells required to obtain a relative sampling error of less than 5% was 425.2 ± 102.2 cells. The average number of analyzed cells used by the specular microscope to generate the data was 247.4 ± 51.6 cells. The average endothelial area of the analyzed cells was 0.43 ± 0.08 mm. The mean sampling error was 3.7% ± 0.6%, and an average of 2.95 ± 0.74 images was needed to obtain a relative sampling error of less than 5%. CONCLUSIONS: We conclude that, theoretically, a minimum of 425.2 cells from 2.95 images must be marked to obtain reliable results, which could possibly represent the real endothelial clinical condition of the whole cornea.

[Reliability of predictable postoperative visual acuity of cataracts as measured by Heine Lambda 100 retinometer preoperatively]. / Confiabilidade da previsão da acuidade visual pós-operatória de catarata mediante medição da acuidade visual pré-operatória utilizando o retinômetro Heine Lambda 100.

PURPOSE: To assess the relationship between potential visual acuity obtained before cataract surgery using Heine Lambda 100 retinometer with best corrected visual acuity 3 months postoperatively, as well as its correlation with the morphological pattern of the dominant cataract and the intensity of nuclear opacification. METHODS: Prospective study executed in the Ophthalmology Hospital Laser Vision in Santos of 121 eyes of 70 patients who underwent cataract surgery (phacoemulsification with intraocular lens implantation), from April to July, 2009. In the preoperative period, Heine retinometer test was performed under mydriasis and its results were compared to postoperative best corrected visual acuity three months after surgery and correlated with the morphological classification of cataracts, being considered a satisfactory result those who did not vary more than two lines in Snellen chart. RESULTS: The satisfactory cases found in our study were 86.78%, with results of visual acuity with Heine retinometer equal to the postoperative visual acuity in 34.7% of the cases. Predominant nuclear opacity N1+ has a higher reliability than N2+ and N3+ (50%, 31.3% and 26.7%, respectively). Regarding all studied eyes, statistical significance was noted (p<0.0001). CONCLUSION: In most cases Heine retinometer underestimated or maintained best corrected visual acuity 3 months postoperatively in patients who underwent cataract surgery. With respect to the morphological classification of cataracts, the higher the opacity of the nuclear lens, the greater the visual acuity underestimation.

Confiabilidade da previsão da acuidade visual pós-operatória de catarata mediante medição da acuidade visual pré-operatória utilizando o retinômetro Heine Lambda 100 / Reliability of predictable postoperative visual acuity of cataracts as measured by Heine Lambda 100 retinometer preoperatively

Objetivo: Utilizar o retinômetro de Heine Lambda 100 para avaliar a relação da acuidade visual obtida no pré-operatório de cirurgia de catarata com a acuidade visual obtida 3 meses no pós-operatório com correção óptica, bem como, sua correlação com a classificação morfológica dominante da catarata e com a intensidade da opacificação quando do tipo nuclear. Métodos: Trata-se de um estudo prospectivo realizado no Hospital Oftalmológico Visão Laser, em Santos, envolvendo 121 olhos de 70 pacientes avaliados de abril a julho 2009, submetidos à cirurgia de catarata sob a técnica de facoemulsificação com implante de lente intraocular. No período pré-operatório, foi realizado o retinômetro de Heine sob midríase e seu resultado foi comparado à melhor acuidade visual pós-operatória do terceiro mês e correlacionado com a classificação morfológica da catarata, quando do tipo nuclear, sendo denominado satisfatório aquele resultado que não variou mais do que duas linhas na tabela de Snellen. Resultados: Os resultados satisfatórios em nosso estudo foram de 86,78 por cento, apresentando resultados de acuidade visual com retinômetro de Heine igual ao resultado da acuidade visual pós-operatória em 34,7 por cento. A opacidade predominantemente nuclear N1+ tem um porcentual de acerto maior do que N2+ e N3+ (50 por cento, 31,3 por cento e 26,7 por cento, respectivamente). Em relação ao total de olhos, observamos um teste extremamente significante (p<0,0001). Conclusão: O retinômetro de Heine hipoestimou ou manteve a acuidade visual pós-operatória corrigida após 3 meses dos pacientes submetidos à facectomia, na maioria dos casos. Ao correlacionar com a classificação morfológica da catarata, observamos que, quanto maior a opacidade do cristalino do tipo nuclear, maior a hipoestimação da acuidade visual.

Purpose: To assess the relationship between potential visual acuity obtained before cataract surgery using Heine Lambda 100 retinometer with best corrected visual acuity 3 months postoperatively, as well as its correlation with the morphological pattern of the dominant cataract and the intensity of nuclear opacification. Methods: Prospective study executed in the Ophthalmology Hospital Laser Vision in Santos of 121 eyes of 70 patients who underwent cataract surgery (phacoemulsification with intraocular lens implantation), from April to July, 2009. In the preoperative period, Heine retinometer test was performed under mydriasis and its results were compared to postoperative best corrected visual acuity three months after surgery and correlated with the morphological classification of cataracts, being considered a satisfactory result those who did not vary more than two lines in Snellen chart. Results: The satisfactory cases found in our study were 86.78 percent, with results of visual acuity with Heine retinometer equal to the postoperative visual acuity in 34.7 percent of the cases. Predominant nuclear opacity N1+ has a higher reliability than N2+ and N3+ (50 percent, 31.3 percent and 26.7 percent, respectively). Regarding all studied eyes, statistical significance was noted (p<0.0001). Conclusion: In most cases Heine retinometer underestimated or maintained best corrected visual acuity 3 months postoperatively in patients who underwent cataract surgery. With respect to the morphological classification of cataracts, the higher the opacity of the nuclear lens, the greater the visual acuity underestimation.