Faculty Bibliography

PURPOSE: To develop a new diabetic retinopathy severity scoring system and to determine if it can monitor changes from baseline as well as identify precise features that have changed over time. Such a grading system could potentially provide an understanding of the impact of treatments utilizing an algorithmic scoring technique. METHODS: The traditional ETDRS grading system was examined and a flow algorithm based on the grading approach was created. All visual comparative assessment points, relying on identification of features in relation to prior standard photographic images, were evaluated and quantified. A new grading form was created that provided fields that captured all relevant features required for determining the ETDRS grading score. A computer software algorithm was developed that examines all entered fields and calculates the appropriate diabetic severity score. RESULTS: This diabetic retinopathy scoring algorithm system was successful in generating a severity score comparable to traditional methods of grading images. Validation with traditionally graded images was performed, demonstrating that in a majority of cases, the severity scores were comparable. The algorithmic grading system was then used to analyze images obtained in a large clinical study of diabetic macular edema, resulting in data regarding baseline scoring values, as well as detailed features of the microvasculature that drove the severity scoring results, and changes seen during the trial. CONCLUSION: This new algorithmic diabetic severity scoring system provides a means to monitor the progression or regression of retinopathy with therapeutic intervention as well as assess the individual microvascular features that may be modified over the course of treatment.

OBJECTIVE:To investigate the varying difficulty of Snellen letters in children with amblyopia. METHODS:We tabulated the letter-by-letter responses of amblyopic and nonamblyopic fellow eyes on random, computer-generated Snellen lines. Participants were 60 children, aged 5 to 13 years, with a history of amblyopia. Main outcome measures were relative difficulties of Snellen letters and common misidentifications. RESULTS:Errors were 7.5 times more common with certain letters (B, C, F, S) than with others (A, L, Z, T), this difference increasing to 17.6-fold at threshold. Similar relative letter difficulty was demonstrated at lines above and at visual acuity thresholds, and both difficult and easy letters were the same for amblyopic and nonamblyopic fellow eyes. Specific misidentification errors were often repeated and were often reciprocal (eg, B for E and E for B). CONCLUSION/CONCLUSIONS:Since therapeutic decisions in amblyopia management are often based on small differences in visual acuities, the relative difficulties of letters used in their measurement should be considered. The Early Treatment Diabetic Retinopathy Study system should be considered for use in this clinical setting.