Adult‐onset myopia associated with diabetes, a new phenomenon?
Authors: Fledelius Hans C. 
Published: May 2009

Abstract From out‐patients seen in our hospital eye clinic the impression was gained that myopia was more frequent in the subgroup of diabetics than in other patient groups, apparently a new clinical observation. The impression got support from a 1981‐investigation into refractive state as related to age, with a preliminary report given at the 1982 San Fransisco Myopia Conference (cf. Conference Report). All patients came from other departments as routine referrals for general (non‐ophthalmic) disease, e.g. hypertension and neurological problems, a material considered refractively unselected. The complete data were published 1983 (Acta Ophthalmol. 61, 545–559). Comparing diabetics with non‐diabetics, 38% of the former were myopic, against 27.5% of the latter. Diabetics' surplus mainly consisted of low degree myopia cases.

This trend is further explored in the present study, analysing 80 diabetics and 80 non‐diabetics with bilateral myopia to find out whether there is a special type of diabetic myopia. Excluded from the series were diabetics with dysregulation, patients with marked proliferative retinopathy and patients with corneal pathology or lens opacities. A concise memory regarding personal spectacle history qualified for inclusion, because in most cases interviews were the only means of obtaining information about myopia onset and progression. The final age range became 21–77 years, with 80% between 30 and 60.

The detailed manuscript having been submitted for publication in Acta Opthalmol., only the main results will be given here.

The median refractive values were ‐2.0 D. in diabetics and ‐3.0 D. in non‐diabetics. Diabetics' relative shift towards lower myopia was significant, as was also their shift towards later onset of myopia. Median onset ages were 18 and 15 years respectively.

Myopia preceded diabetes in 47/80 of this subgroup while 33 acquired their myopia as diabetics, with a latency of 0–18 years. 13 of the 33 had juvenile diabetes and 20 diabetes of adult‐onset. ‐ In general there was a high share of adult‐onset myopia in the sample of diabetics, namely 40%; most patients had very low myopia. The same applied to adult‐onset myopia in the controls; it appeared in 22.5% of the non‐diabetics.

For the whole sample, adult‐onset myopia was more frequent than generally assumed. Selection bias could not be ruled out, as a contributing factor. The results are, however, in keeping with other recently published series of refraction in adults. All‐together, the available data seem to refute classical textbook presentations claiming that myopia is usually appearing and progressing during childhood and/or adolescence only, while stable ‘when maturity is reached’. This extra share of adult‐onset myopia may explain (at least part of) the apparent increase in myopia prevalence otherwise considered a product of industrial communities' way of life, since reference materials often comprised adolescents only.

Except for the surplus of adult‐onset myopia of lower order, there is no indication of a special type of diabetic myopia. Specific features have not been found, but further studies are required to corroborate or reject this view. An increased lens power (due to altered carbohydrate metabolism) may seem the most probable working hypothesis concerning diabetic myopia. The explanations otherwise most ready ‐ cataractous changes and transient metabolic dysregulation ‐ can be turned down since both clinical states were reasons for exclusion from the sample under study. Further, if overlooked, the associated refractive change might as well be away from as towards myopia. ‐ The general question remains whether it is the more effective diabetes regulation of to‐day that has led to the new refractive trend.