Br J Ophthalmol: first published as 10.1136/bjo.72.9.641 on 1 September 1988. Downloaded from British Journal of Ophthalmology, 1988, 72, 641-645 Photostress recovery in chronic open angle glaucoma MARK D SHERMAN AND PAUL HENKIND* From the Department ofOphthalmology, Albert Einstein College ofMedicine and Montefiore Medical Center, Bronx, New York, USA SUMMARY Photostress recovery time was measured in 30 eyes from 15 patients with chronic open angle glaucoma, and 30 eyes from 15 individuals of a similar age group with no ophthalmological disorder. The average recovery time in patients with glaucoma was 70 47 (SD 35-39) seconds. The average recovery time in the control population was 41-97 (SD 17.34) seconds. This difference was statistically significant (p<O0OO1). There was a small positive correlation between age and recovery time in the control population, whereas there was no correlation between age and recovery time in the glaucoma group. There was no correlation between visual acuity and recovery time for either group. There was also no correlation between intraocular pressure and recovery time for the glaucoma group. It was not possible to control for pupillary dilatation in this study. However, it has been previously demonstrated that pharmacological meiosis will not delay photostress recovery time in normal subjects. This is the first report of photostress recovery testing in patients with chronic open angle glaucoma. The results are discussed in terms of the pathophysiology of glaucoma and previous photostress studies in patients with macular disease. copyright. Photostress recovery time (PSRT) has frequently the time required for the eye to return to baseline been used as a quantitative measure of macular visual acuity once the illumination period is over. The function. Initially described by Magder' as a clinically time required to return to baseline acuity is recorded http://bjo.bmj.com/ useful tool for following the progression of central as the photostress recovery time. The photostress serous retinopathy, photostress recovery has also response is not entirely understood but has been been utilised in the study of the ocular toxicity of explained as a transient state of visual insensitivity antimalarial medications,2 ocular toxicity of birth caused by bleaching of the visual pigments of the control pills,3 and various macular and optic nerve retina.7 Return of sensitivity is dependent on resyn- diseases."7 Although a precise pathophysiological thesis of the visual pigments, and resynthesis requires explanation for aberrant photostress responses has adequate perfusion of the photoreceptors and the on September 27, 2021 by guest. Protected yet to be offered, it has been clearly demonstrated pigment epithelium. The process is independent of that optic nerve and macular disease can be differen- optic nerve integrity. tiated on the basis of PSRT, where the retina with In order to standardise the approach and simplify macular disease has an increased recovery time and the implementation of photostress testing a hand that with optic nerve disease has a normal recovery held instrument was designed to measure photostress time.7 recovery time.' With this instrument, called a sco- A major criticism of photostress recovery testing tometer, the toxic effects of antimalarial medications has been the lack of a standardised technique in on the retina, as manifested by an increased recovery conducting the test. The test consists in measuring time, were demonstrated.2 This instrument has also the visual acuity of a given eye, illuminating that eye been used to demonstrate the toxic effects on the with a high intensity light for a specific length of retina of birth control pills.3 Glaser et al. used an time-creating a central scotoma-and measuring ordinary penlight for an illumination period of 10 *Deceased. seconds to compare recovery time in patients with Correspondence to Mark D Sherman, MD, Department of Ophthal- macular disease and optic nerve disease.7 They found mology, University of Arizona Health Sciences Center, Tucson, a small increase in recovery time with increasing age Arizona 85724, USA. in both groups and defined a normal recovery time as 641 Br J Ophthalmol: first published as 10.1136/bjo.72.9.641 on 1 September 1988. Downloaded from %64FAr2 Mark D Sherman and Paul Henkind less than 50 seconds. Patients with macular disease (4) The same procedure was then conducted for (senile macular degeneration, submacular drusen the left eye, with the right eye occluded. without serous detachment, diabetic retinopathy, Intraocular pressure was measured for the COAG cystoid oedema) had an average recovery time group with a non-contact air tonometer. After being greater than 150 seconds; eyes with optic nerve photostress tested each patient received a routine disease (optic neuritis, optic atrophy, ischaemic optic ophthalmological examination from an ophthal- neuropathy, lymphomatous infiltrations) had mologist who was not aware of the patient's photo- recovery times of 50 seconds or less. The authors stress scores. Each patient's chart was later reviewed concluded that photostress recovery testing was 'a for data on visual field defects, systemic disease, valuable adjunct in the clinical assessment of medication history, and previous ophthalmological decreased vision and a sensitive discriminator procedures and findings. Each control patient had a between occult optic neuropathy and subtle normal anterior and posterior eye. maculopathy.'7 The following study presents the results of photo- Results stress recovery testing in patients with chronic open angle glaucoma and patients of a similar age group Only data from patients who were capable of having having no ophthalmological disorder. both eyes tested were included in the data analysis. The COAG group consisted of patients with a Subjects and methods diagnosis of glaucoma in both eyes. The photostress recovery time for each eye of a given patient was We prospectively studied photostress recovery time averaged to provide a single photostress score for in patients with chronic open angle glaucoma that patient. (COAG) being followed up at the Glaucoma Clinic Table 1 summarises the clinical data for patients in of Montefiore Hospital, and patients from the Table l Clinical dataforpatients with glaucoma General Eye Clinic with no known ophthalmological copyright. disorder. was The ophthalmoscope recharged before Age (yr), Eye Visual Intraocular PSRT* (s) Recovery each testing period for at least eight hours. The sex acuity pressure scoret (s) photostress test was performed before any pharma- (mmHg) cological preparation for routine ocular examination. 73, F OD 20/70 16 150 150 Photostress testing was conducted as follows: OS 20/50 14 150 (1) Best corrected visual acuity was determined for 78, F OD 20/50 12 42 62 each eye with Snellen test letters at a distance of 6 m OS 20/40 15 82 (20 feet). All subsequent measurements were 44, F OD 20/25 14 28 74 OS 20/25 13 120 http://bjo.bmj.com/ obtained with the same chart, under the same lighting 78,F OD 20/40 18 32 32-5 conditions, and by the same investigator. All eyes OS 20/30 20 33 were undilated. Because of the limited number of 72, M OD 20/40 9 35 66 large test letters on the Snellen chart and the possi- OS 20/30 1 1 97 77, F OD 20/30 15 19 72 bility of consequent inaccuracy of measurements, the OS 20/25 15 125 data were considered invalid for eyes with visual 77, M OD 20/40 21 48 53 acuity less than 6/30 (20/100) and were eliminated OS 20/30 19 58 71, M OD 20/70 22 150 111 from the analysis. on September 27, 2021 by guest. Protected OS 20/50 30 72 (2) The right eye was tested first, with the left eye 74, M OD 20/30 15 42 42 covered by an opaque shield. The patient was OS 20/30 18 42 instructed to look directly into the halogen bulb 51, M OD 20/25 16 43 32 attachment of a Welch Allyn halogen bulb ophthal- OS 20/25 19 21 76, F OD 20/40 21 88 59 moscope, which was held 2 to 3 cm from the eye for OS 20/30 15 30 an illumination period of 10 seconds. 68, F OD 20/30 14 22 39 (3) Immediately after the light was removed the OS 20/30 14 56 patient was instructed to read the Snellen chart, 63, M OD 20/50 29 81 115-5 OS 20/50 25 150 starting at the first visible line and continuing to 56, F OD 20/25 33 50 41 increasingly smaller lines as they became clear. The OS 20/25 21 32 recovery time was recorded as the time (in seconds) 66, M OD 20/25 NAt 73 108 required for the patient to read correctly three letters OS 20/25 NA 143 of the line just above that recorded as best visual *Photostress recovery time. acuity. Recovery time was recorded to a maximum of tAverage PSRT. 150 seconds. fNot available. Br J Ophthalmol: first published as 10.1136/bjo.72.9.641 on 1 September 1988. Downloaded from Photostress recovery in chronic open angleglaucoma 643 Table 2 Clinical dataforcontrolpatients 60 55 50 o Control Data Age (yr), sex Eye Visualacuity PSR7P (s) Recovery * Glaucoma Data scoret (s) 45 w 40 67, M OD 20/70 20 34 0.> 35 Os 20/50 48 F 30 60, M OD 20/30 45 34 25 OS 20/30 23 a0 68,F OD 20/30 35 33 5 20 OS 20/30 32 15 79,F OD 20/30 79 96 5 10 Os 20/30 114 5 67, F OD 20/25 31 34 0 :11.11111n 1 N_ mv ND 0 0 -N m v OS 20/25 37 o o oo _- T- CY C# IV 60, M OD 20/25 20 33 Cl U, I- OS 20/30 46 01 r V- 51, M OD 20/25 22 21-5 Recovery Time (s) OS 20/20 21 56, M OD 20/25 45 41 Fig.