Secondary Cataract

We tested the procedure in 53 eyes: 15 corresponding to a group of normal young subjects (average age = 28±5 y/o); and the other 38 eyes (average age = 73±7 y/o) were patients with diagnosed cataracts. One eye per patient was evaluated. Every patient was informed of the subject of the study, and a written informed consent obtained, following the tenets of the Declaration of Helsinki. The study protocol was approved by the “Hospital Virgen de la Arrixaca” ethics committee. Firstly, we evaluate the subjects' visual acuity and refraction. In every subject, an ophthalmological exam was completed, including Optical Coherence Tomography (OCT) measurements to discard macular problems and the recording of images of the crystalline lens provided by a slit-lamp device, after dilating the pupil by instilling 0.2 ml of tropicamide (1%).
Inclusion criteria for the group of cataract patients was nuclear cataract with increasing lens opacity, although not all cases were purely nuclear cataracts, as some subjects also showed slight degree of capsular opacification. Every patient was classified according to the degree of nuclear opacification (NO), by using the LOCSIII chart [4] (link), following the subjective decision of the ophthalmologists participating in the study. The 38 cataract eyes were classified as follows: 12 eyes as grade 2 (NO2), 18 eyes as grade 3 (NO3), and 8 eyes as grade 4 (NO4).

The study design was a retrospective population-based survey. The data from all patients who underwent cataract surgery alone or in combined procedures in Poland between January 2010 and December 2015 were assessed from the national database of hospitalizations [9 ]. This database is maintained by NFZ, which compiles all data related to hospitalizations in public and private hospitals financed from public sources. The information includes medical data, identification number, date of birth, area code, and sex of patients. The medical data include the diagnoses coded according to the International Classification of Diseases, 10th Revision, and all procedures performed coded using the International Classification of Diseases, 9th Revision (ICD-9) procedure codes and unique NFZ codes corresponding to certain hospital procedures.
For each individual patient, cataract surgery alone or as a combined procedure with corneal transplantation, glaucoma filtrating surgery, or vitrectomy was retrospectively identified. The ICD-9 code 13.4 was used to identify cataract extraction performed by phacoemulsification, with 13.2, 13.3 and 13.5 codes used to identify other types of cataract extractions. The following NFZ codes were used: B12, B13, B14, B15, B18, and B19 corresponding to cataract surgery alone; B04, B05, and B06 corresponding to cataract surgery combined with corneal transplantations; B11 corresponding to cataract surgery followed by glaucoma filtrating surgery; and B16 and B17 corresponding to cataract surgery combined with vitrectomy. The number of one-day procedures was also obtained from the NFZ data. The wait time data and the number of patients waiting for cataract surgery were obtained from the national registry [10 ].
For statistical analysis, the socio-demographic data of cataract patients including age, sex and place of residence were anonymously recorded. Data regarding the population of Poland were obtained from Central Statistical Office of Poland (Głowny Urzad Statystyczny) [11 ]. The incidence of cataract surgery was presented for each year separately and by age category matched with corresponding year population data in Poland. The statistical analysis also included the annual volume of cataract surgery, calculations of cataract extractions performed by phacoemulsification, calculations of proportions of one-day and combined procedures, and data regarding the number of cataract surgeries received by Polish patients in other European Union countries. The number of patients having cataract surgery in the second eye was collected, and the wait times were calculated. The Kaplan–Meier method was used to calculate the cumulative probability of second-eye cataract surgery during 2010–2015 with a log-rank test to compare the curves between periods. The demographic characteristics of patients are presented with the mean and standard deviation (SD). The study protocol was approved by the Polish Ministry of Health.

A single surgeon (Yanlong Bi) performed all the surgeries under retrobulbar anesthesia. Before the surgery, the conjunctiva and cornea within the operative field were disinfected with 5% povidone-iodine (Shanghai Likang Disinfection High-tech Co., Ltd., China) for 3 min. Cataract surgery was performed via a clear corneal incision, viscoelastic substance (IVIZ, Bausch & Lomb, USA) injection, anterior capsulorhexis, and phacoemulsification, followed by implantation of an intraocular lens (IOL) (ASPIRA-aAY, HumanOptics, Erlangen, Germany). After cataract surgery, standard and complete PPV was performed using a 25-gauge instrument. Next, the internal limiting membrane (ILM) was peeled 360° around the macular hole (MH) after staining with indocyanine green and then inserted into the MH smoothly. Sterile air was injected at the end of the vitrectomy. The patients were asked to maintain face-down positioning for at least 7 days after surgery.

This post-market clinical investigation was a prospective, multicentric, randomized, bilateral, comparative, paired-eye, open-label study at 4 study sites in France and Germany with a 3-year postoperative follow-up.
The Ethics Committee of the Heidelberg University, Heidelberg, Germany approved the study and informed consent was obtained from all participants. This study was conducted in accordance with Good Clinical Practices, ISO 14155:2011, the Declaration of Helsinki and all other applicable laws and regulations in Germany and France. This study has been registered in the German Clinical Trials Register on 18/08/2017 under the trial registration number DRKS00012768.
The primary endpoints were evaluation of glistening and measurement of PCO at 3-years postoperatively.
Standardized retroillumination photographs of the pseudophakic anterior segments were obtained following pupil dilation at each postoperative visit. Density areas were identified and marked on the computer screen by a grader. The individual PCO score for each eye was calculated via Evaluation of Posterior Capsule Opacification (EPCO) by multiplying the density of the opacification (graded from 0 to 4) by the fractional PCO area involved behind the IOL optic. The EPCO assessment has been performed by an external independent blinded Reading Center. EPCO calculated the surface density of opacification mathematically by performing pixel counts. The density of the opacification behind the IOL was clinically graded as follows: 0 = none; 1 = minimal; 2 = mild; 3 = moderate; 4 = severe. Additionally, routine slit lamp examinations were done to subjectively assess the degree of posterior capsular bag opacification.
At each center, a single investigator assessed the number of glistenings on the slit lamp under pupil dilatation for paired eyes. The observer was masked for the visual testing results and IOL type, and rated glistenings based on the modified severity rating scale as published by Christiansen et al. 2001^{14 (link)}, where 0 = “None”, + 0.5 = ”rare” (< 10 glistenings), + 1 = (10 to 20 glistenings), + 2 = (20–30 glistenings), + 3 = (30–40 glistenings), and + 4 = (> 40 glistenings). The amount of glistenings were evaluated under a slit lamp field of maximum height (e.g., 10.0 mm) and 2.0 mm width.
Secondary endpoints included Best Corrected Distance Visual Acuity (BCVA), proportion of subjects achieving a BCVA in Snellen of ≥ 20/40 (0.3 logMAR), and contrast acuity (CA). Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity charts were used in an illuminated light box to determine uncorrected visual acuity, BCVA, and low contrast VA based on the number of letters read at 4.0 m distance under photopic (85 cd/m² ± 10) lighting conditions. In addition, the low contrast acuity was measured with best distance correction in place using the 10% contrast ETDRS charts at a distance of 4 m under photopic (85 cd/m² ± 10) lighting conditions. Subjective refraction was also collected during study specific examinations. Postoperative examination was done using the ETDRS charts at 4 m distance under photopic lighting conditions. Safety endpoints included medical and lens complication rates, adverse events, and optical/visual symptoms.