Predicting acuities in patients with cataracts.

Correspondence Predicting acuities in patients with cataracts SIR, Rarely have I read with such interest an article published in a major refereed ophthalmological scientific journal. The article by Halliday and Ross' is of interest. I completely agree with their statement that any surgeon relying on interferometers to predict postoperative acuities in cataract patients might seriously misjudge the visual potential of many patients. In the May issue of the American Journal of Ophthalmology I outlined how the surgeon must combine all of his clinical acumen and other testing knowledge to fully utilise the results of interferometer tests.2 I agree with the authors that the results with the retinometer and the visometer are identical. For this reason I refer to both of them as interferometer testing.3 The patients studied were 50 whose eyes were operated on for cataracts, some of which had extracapsular procedures. Halliday and Ross were particularly concerned about the 8 patients whose interference visual acuity was better than their final postoperative Snellen chart visual acuity. One of their patients had cystoid macular oedema, 2 had diabetic retinopathy, 2 had senile macular degeneration, and 3 had 'normal eyes which may be assumed to have some degree of amblyopia.' These patients had diagnoses that fell into the group of clinical conditions that I point out should be recognised pre-operatively and give 'false positive' readings with the inter-ferometers. This being the case, these patients should have been recognised preoperatively. Therefore the interference visual acuity is meaningless in predicting postoperative Snellen visual acuity. Did the 2 patients with diabetic retinopathy have cystoid macular oedema? Did the patients with senile macular degeneration have serous fluid under the sensory epithelium of the macula or geographic atrophy of the pigment epithelium of the macula? Did the 'three normal eyes' indeed have amblyopia, or could they have been in the group of patients with extracapsular procedures who may have had some clouding of the posterior capsule? We were not given these pertinent pieces of data. I and others have demonstrated that cystoid macular oedema, serous fluid under the sensory epithelium of the macula, geographic atrophy of the pigment epithelium, amblyopia, and clouding of the posterior capsule after extracapsular surgery cause a disparity between the interference visual acuity and Snellen visual acuity.2 The authors reported on 8 patients with mature cataracts who failed to see the interference patterns. This has been well documented in the literature, and these …