糖尿病性網膜症の軟性白斑発症に関与する臨床因子

Clinical factors associated with soft exudates in diabetic retinopathy

　軟性白斑（綿花様白斑）の発症と臨床因子との関連性について検討し，軟性白斑発症前後における血液網膜柵の透過性の変化についても検討した。

　東大病院眼科糖尿病外来で1年間以上，平均20.6ヵ月間観察し得た，単純性及び増殖前糖尿病性網膜症を有するインスリン非依存型糖尿病患者96人を対象とした。糖尿病性網膜症における軟性白斑の発症には，血糖コントロールが関連しており，全身合併症としては神経障害との関連が強くみられた。経過観察中に軟性白斑が出現した例では，眼科初診時に比べ軟性白斑出現時には空腹時血糖値とグリコヘモグロビン（HbAlc）値の平均値が共に有意に低下していた。血液網膜柵の破綻による透過性亢進が，軟性白斑の出現に関連していた。

We evaluated the statistical relation among the presence of onset of soft exudates, clinical factors, and the state of blood-ocular barrier as seen by fluorophotometry. We followed up a series of 152 eyes, 96 cases, of non-insulin dependent diabetes mellitus for periods more than one year, average 20. 5 months. We divided the series into 3 groups. Group 1 included 49 eyes which manifested no soft exudates initially but manifested them later during the course of follow-up. In group 2 (51 eyes), soft exudates were present at the start of observation. In group 3 (52 eyes), soft exudates were present initially but disappeared during the course of fol-low-up.

We observed higher levels of fasting blood glu-cose and HbAlc in group 1 and 2 than group 3. Among systemic manifestations of diabetes pres-ence of diabetic neuropathy was the sole feature associated with soft exudates. In group 1, fasting blood glucose and HbAlc values were significantly elevated before appearance of soft exudates than after. Concentration of vitreous fluorescein in group 1 was elevated after appearance of soft exudates than before. No significant changes were seen in concentration of vitreous fluorescein in group 3 when examined after a mean interval of 5. 7 months.

Above findings show that onset of soft exudates is positively correlated with blood glucose control and diabetic neuropathy. Breakdown of blood -retinal barrier seemed to be implicated in the pathogenesis of soft exudates.