Mirko Resan

The acute phase of inflammatory response involved in the wound-healing process after excimer laser treatment

Purpose To evaluate the participation of proinflammatory cytokines in the acute phase of corneal wound-healing response after excimer laser treatment. Methods The study included 68 myopic eyes up to −3.0 diopters divided into two groups: 1) eyes treated with laser in situ keratomileusis (LASIK) (n=31) and 2) eyes treated with photorefractive keratectomy (PRK) (n=37). Each group was then divided into three subgroups based on tear sampling times: before (0 hours), 1 hour after, and 24 hours after treatment. The tear fluid was sampled from lower lateral tear meniscus using a cellulose microsurgical sponge. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 in tear fluid were determined by flow cytometry method. Results Statistical significance was observed in the concentrations of TNF-α (P=0.0421) and IL-1β (P=0.0225) between samples collected 1 and 24 hours after PRK treatment in favor of samples collected 1 hour after treatment. IL-6 concentration changes showed a significant increase in the PRK group in both time intervals following treatment compared to pretreatment (0 hour/1 hour, P=0.0031; 0 hour/24 hours, P=0.0059). For IL-8 concentrations, significant differences were observed between control and experimental groups in samples collected 1 hour after LASIK and 1 hour after PRK treatment (P<0.001 for both groups), and IL-8 concentrations between control and experimental groups in samples collected 24 hours after LASIK and 24 hours after PRK treatment were greater after PRK treatment (P=0.0005). Comparison of average concentration values of proinflammatory cytokines in all the tested samples between LASIK and PRK groups showed significantly higher levels of IL-1β in the LASIK group 24 hours after treatment (P=0.0134), and of IL-6 in the PRK group 24 hours after treatment (P=0.0031). Conclusion The acute phase of corneal wound healing after excimer laser treatment is defined by an intensive inflammatory response. After PRK treatment, there were increased concentrations of TNF-α and IL-1β in tear samples 1 hour after treatment, IL-6, 1 and 24 hours after treatment, and IL-8, 1 and 24 hours after treatment. After LASIK treatment, there were increased concentrations of IL-8 in tear samples 1 hour after treatment and IL-1β, 24 hours after treatment. Both PRK and LASIK methods are characterized with a significant inflammatory response. However, tear findings following PRK method showed more intensive inflammatory response than the findings after LASIK method.

Toric Intraocular Lenses for the Correction of Astigmatism

The ideal procedure for the correction of astigmatism should provide: precise and accurate adjustment, safety, predictable outcome, lasting effect and simplicity with an acceptable price. Conventional methods for solving problems such as glasses and/or contact lenses at the present time often do not meet the needs of patients. Whether it is the objective or subjective reasons for a large number of patients tend to avoid wearing glasses or contact lenses.

Metabolic control and diabetic retinopathy in patients with diabetes type 2

ZusammenfassungZIELSETZUNG: Die Bewertung der Korrelation zwischen Wechselstoffkontrolle und Präsenz und Schweregrad der diabetischen Retinopathie (DR) bei Patienten mit Typ-2-Diabetes. METHODEN: Diese Querschnittstudie umfasste 80 Patienten, die in vier Gruppen eingeordnet wurden, nach der Dauer der Krankheit: de novo; bis zu 10 Jahren; 11 bis 20 Jahre; und über 20 Jahre. Um die Stoffwechselkontrolle zu bewerten wurden bei jedem Patient die folgenden Parameter getestet: glycosiliertes Hämoglobin (HbA1c), Gesamtcholesterinspiegel (TC), High-Density Lipoprotein Cholesterin (HDL-C), Low-Density Lipoprotein Cholesterin (LDL-C) und Triglyceride (TG). Abhängig von der Änderung an der Netzhaut wurden die Patienten nach der Klassifizierung der Amerikanischen Akademie für Augenheilkunde eingeordnet. ERGEBNISSE: Patienten mit DR hatten deutlich erhöhte HbA1c-Werte (9,5 ± 1,83%) und verringerte HDL-C-Werte (1,1 ± 0,21 mmol/L) im Vergleich zu Patienten ohne DR (6,9 ± 1,29%, t = 5,088; p < 0,001 und 1,3 ± 0,25 mmol/L, t = 3,022; p < 0,01). Die Präsenz und der Schweregrad der DR standen in positiver Wechselwirkung mit HbA1c-Werten (p < 0,001) und schlechter glykämischer Kontrolle (p < 0,001), während sich HDL-C Werte umgekehrt proportional zur Präsenz (p < 0,01) und zum Schweregrad der DR (p < 0,05) verhielten. SCHLUSSFOLGERUNG: Schlechte Stoffwechselkontrolle, gemessen anhand erhöhter HbA1c-Werte und verringerter HDL-C-Werte, steht in Wechselwirkung mit der Präsenz und dem Schweregrad der DR.SummaryAIM: To evaluate the correlation between metabolic control and the presence and severity level of diabetic retinopathy (DR) in patients with diabetes type 2. METHODS: This cross-sectional study included 80 patients divided into four groups according to the duration of the disease: de novo; up to 10 years; from 11 to 20 years; and over 20 years. In order to evaluate the metabolic control each patient was tested for: glycosylated hemoglobin (HbA1c), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). According to eye fundus changes patients were classified following the American Academy of Ophthalmology classification. RESULTS: The patients with DR had significantly increased values of HbA1c. (9.5 ± 1.83%) and decreased values of HDL-C (1.1 ± 0.21 mmol/L) compared to patients without DR (6.9 ± 1.29%, t = 5.088; p < 0,001) and (1.3 ± 0.25 mmol/L, t = 3.022; p < 0.01) respectively. The presence and severity level of DR correlated positively with HbA1c values (p < 0.001) and poor glycaemic control (p < 0.001) while HDL-C values correlated inversely with the presence (p < 0.01) and severity level of DR (p < 0.05). CONCLUSION: Poor metabolic control determined by the increased values of HbA1c and decreased values of HDL-C correlates with the presence and severity of DR.

[Evolution of cataract surgery: smaller incision--less complications].

BACKGROUND/AIM Cataract surgery has become one of the safest procedures in medicine thanks to advances in technology and surgical techniques. Although minimal, we still witness different complications. The aim of this study was to compare visual outcome and complication rate in different techniques of cataract surgery, ie in cataract surgeries with various corneal incision width. METHODS The study included 3,457 consecutive patients, ie 4,670 eyes that had undergone cataract surgery. The used surgical techniques were: extracapsular cataract extraction, phacoemulsification/forceps IOL implantation, phacoemulsification/injector IOL implantation, microincision cataract surgery (MICS). Patient follow up was 6 months. Patients were evaluated for: visual aquity, corneal astigmatism, cellular reaction in the anterior chamber, IOL position. RESULTS Uncorrected visual aquity 30 days postoperatively was > or = 0.5 in 30% of the eyes - ECCE; 54.7% of the eyes - phacoemulsification/forceps IOL implantation; 63.0% of the eyes - phacoemulsification/injector IOL implantation; 5/8 of the eyes - MICS. Endophthalmitis was detected in 0.15% of the eyes - ECCE and 0.1% of the eyes - phacoemulsification/forceps IOL implantation. In eyes with phacoemulsification/injector IOL implantation or microincision cataract surgery (MICS) there were no cases of endophthalmitis. After a 6-month period intraocular lens were dislocated in 7.2% of the eyes - ECCE, and 0.6% of the eyes - phacoemulsification/PMMA IOL. There was no IOL dislocation in other surgical techniques. CONCLUSION Shorter corneal incision implies less complications, less operative trauma, faster visual rehabilitation and better visual outcome.

Corneal Surgical Techniques

There is a long history of corneal refractive surgery. Leonardo Da Vinci in 1508 said the theory of refractive errors. The first systematic analysis of the nature and results of refractive errors came from Francis Cornelius Donders. His classic treatise, “On the anomalies of accommodation and refraction of the eye”, outlined the fundamental principles of physiological optics. Ironically, in this treatise, Donders railed against surgical attempts to correct refractive errors by altering the corneal shape. In 1885 Hjalmar Schiotz performed corneal incision to correct astigmatism. Modern refractive surgery extended corneal reshaping to treat myopia and astigmatism. Throughout the 1930s and 1940s, Sato published several reports, describing his attempts to refine incisional refractive surgery with anterior and posterior corneal incisions. The Russian ophthalmologist, Fyodorov later developed a systematic process of anterior radial keratotomy and treated thousands of myopic patients with greater predictability. Lamellar surgery was first introduced by Jose Barraquer. He invented keratoplasty procedures that involved the transplantation of corneal tissue of a size different from the host size to alter the curvature of cornea. He also invented a series of lamellar procedures and developed a formula that represented the relationship between the added corneal thickness and the change in refractive power, later called Barraquer’s law of thickness. The transition from incisional to ablative laser refractive surgery arose with the development of Excimer laser technology. Excimer lasers use argon fluoride gases to emit ultraviolet laser pulses. Taboda and Archibald reported the use of the Excimer laser to reshape the corneal epithelium in 1981. In 1983, Trokel and colleagues showed how the Excimer laser could be used to ablate bovine corneal stroma. In 1985, Seiler did the first Excimer laser treatment in a blind eye. He later did the first Excimer laser astigmatic keratotomy. In 1989, McDonald and colleagues did the first photorefractive keratectomy on a seeing eye with myopia. Jose Barraquer’s pioneering work, including the use of lamellar procedures to subtract corneal stromal tissue and the development of the first microkerotomes, set the stage for laser in situ keratomileusis (LASIK) surgery. Ruiz and Rowsey modified Barraquer’s technique to perform keratomileusis in situ with a geared automated microkeratome. In the early 1990s, Pallikaris and colleagues and Buratto and colleagues independently described a technique that combined two existing technologies: the microkeratome and the Excimer laser. Pallikaris coined the term LASIK for this new technique, which has become a widely used refractive technique worldwide (1).