RESUMO
PURPOSE: To describe the tomographic and corneal biomechanical status of a sample of eyes excluded from LVC and to present the differences in biomechanical behavior in relation to cutoffs of clinical- and tomography-based screening methods used in clinical practice. PATIENTS AND METHODS: Observational cross-sectional study including 61 eyes from 32 consecutive patients who were excluded from LVC in our department. Clinical and demographic data were collected from the patients' clinical records. Tomographic data was assessed with a Scheimpflug camera (Pentacam, OCULUS®). Ablation depth (µm) and residual stromal bed (µm) were calculated by the WaveLight® EX500 laser system software (Alcon, EUA). The corneal biomechanical assessment was made through ultra-high speed Scheimpflug imaging during noncontact tonometry (Corvis ST, OCULUS®). Several ectasia risk scores were analyzed. RESULTS: Mean age was 31.0±6 years old and mean manifest spherical equivalent was -2.01 ± 2.3D. Belin-Ambrósio deviation index was the tomographic parameter with higher proportion of eyes within the ectasia high risk interval. In the biomechanical assessment, more than 95% of eyes met the criteria for ectasia susceptibility in four of the first generation and in two of the second generation parameters. In a cutoff based comparative analysis, eyes with Kmax ≥45.5 D, eyes with VCOMA <0 and eyes with ARTmax ≤350 presented significantly softer corneal biomechanical behavior. CONCLUSION: The majority of eyes excluded from LVC in the present study met the criteria for ectasia susceptibility in several biomechanical parameters, validating the clinical and tomographic based screening prior to LVC in our center. Differences found in the biomechanical assessment regarding cutoffs used in clinical practice highlight its differential role in characterizing risk profile of these patients. Tomography should not be overlooked and the integration of all data, including treatment-related parameters, can be the future of risk ectasia screening prior LVC.
RESUMO
PURPOSE: To address the long-term visual function after bilateral pan-retinal photocoagulation (PRP) and its impact in real life, namely on visual field (VF) legal criteria to drive. To determine potential predictors related to clinical factors and treatment strategies. PATIENTS AND METHODS: Observational cross-sectional study. Eyes from diabetic patients diagnosed with diabetic retinopathy who underwent bilateral PRP, with or without macular treatments and with visual acuity legal criteria for non-professional driving were randomly assigned. Main outcomes were: demographic and clinical data including best corrected visual acuity; binocular visual field (EBST-Esterman Binocular Suprathreshold Test, Humphrey analyzer3®); contrast sensitivity (CS-Metrovision-MonPack3®); light scattering in the retina (HD Analyzer, Visiometrics®). RESULTS: Seventy-one diabetic patients included (44 men and 27 women), with a mean age of 62.2±11.8 years. PRP was performed, on average, 9.7±6.9 years before the study. The average EBST Score was 85.8±17.0 and the average CS (2-5cpd) was 19.5±2.9 dB in photopic and 14.2±4.1 dB in mesopic conditions. Through a multivariate regression model, after adjusting to the clinical and demographic factors as possible confounders, we found that treatment factors associated with worse results were the use of Argon laser for the EBST Score, the very confluent PRP for the number of non-viewed points in the central 30°x20° of the EBST and the presence of macular treatments for the CS tests. According to Portuguese law, 79% (n=56) of patients had minimal EBST amplitudes for non-professional driving. CONCLUSION: The functional results achieved in our sample are compatible with an active life, allowing most of the patients included to overcome the requirements of Portuguese legislation for driving light vehicles, namely at the level of the binocular visual field. These results highlight the role of PRP in the treatment of diabetic retinopathy in an era with evolving less aggressive laser options.
