Decline In Acuity Research Articles

Optical Coherence Tomography Findings in Ocular Decompression Retinopathy

Three days following trabeculectomy surgery, a 47-year-old woman experienced a decline in visual acuity to 20/400. Fundus findings were consistent with decompression retinopathy, and optical coherence tomography revealed macular thickening, cystoid macular edema, and neurosensory macular detachment. The foveal anatomy normalized following topical treatment, and visual acuity returned to 20/30 by 10 weeks postoperatively. Both macular detachment and cystoid macular edema may contribute to acute decline in visual acuity in decompression retinopathy. Optical coherence tomography facilitated the prompt detection of treatable pathology, which resolved following appropriate medical therapy.

Pegaptanib sodium for the treatment of neovascular age-related macular degeneration: A review

Objective: This article reviews available informationon the new selective vascular endothelial growth factor aptamer pegaptanib in the treatment of neovascular age-related macular degeneration (ARMD). The pharmacology, pharmacokinetics, pharmacodynamics, contraindications, and drug-interaction potential of pegaptanib are discussed, and the results of clinical trials evaluating its efficacy and tolerability are summarized. Methods: Relevant articles were identified through searches of MEDLINE (1966-June 2005) and International Pharmaceutical Abstracts (1970-June 2005). The search terms included pegaptanib sodium, Macugen, age-related macular degeneration, and choroidal neovascularization. The reference lists of identified articles were reviewed for additional publications, and further information was obtained from the manufacturer of pegaptanib. Included studies were review articles and Phase II, III, and IV clinical trials, with preference given to available Phase III studies. Results: Only 1 research group has evaluated the tolerability and efficacy of pegaptanib in patients with neovascular ARMD. The VEGF Inhibition Study in Ocular Neovascularization involved 2 concurrent randomized trials of intravitreous injections of pegaptanib 0.3 mg (n = 294), 1 mg (n = 300), and 3 mg (n = 296) compared with sham injections (n = 296) every 6 weeks for 54 weeks in patients with neovascular ARMD. Assessments were conducted at 6, 12, 18, 24, 30, 42, 48, and 54 weeks. The primary end point was the proportion of patients losing <15 letters on the study eye chart at 54 weeks. This end point was achieved in 70%, 71%, and 65% of patients who received pegaptanib 0.3 ( P < 0.001), 1 ( P < 0.001), and 3 mg ( P = 0.03), respectively, compared with 55% of those receiving the sham injections. Significant improvements in visual acuity with pegaptanib compared with the sham-injection group were seen at all time points (0.3 and 1 mg: P < 0.002; 3 mg: P < 0.05). The sham-injection group was twice as likely to have severe vision loss (loss of ≥30 letters or 6 lines on the eye chart) compared with those receiving pegaptanib 0.3 or 1 mg ( P < 0.001). Adverse events reported significantly more often in the pegaptanib group compared with the sham-injection group included vitreous floaters (33% vs 28%, respectively; P < 0.001), vitreous opacities (18% vs 10%; P < 0.001), and anterior-chamber inflammation (14% vs 6%; P = 0.001). Injection-related adverse events during the first year of pegaptanib treatment included endophthalmitis in 12 (1.3%) patients, retinal detachment in 6 (0.7%) patients, and traumatic injury to the lens in 5 (0.6%) patients. Conclusions: There are few published clinical data on pegaptanib. In 2 clinical comparisons with sham injections, pegaptanib was well tolerated and effective in slowing the decline in visual acuity in patients with neovascular ARMD. This agent may be considered an option for the treatment of neovascular ARMD.

Verteporfin

Photodynamic therapy (PDT) with verteporfin (Visudyne), a photosensitising protoporphyrin derivative, is used in the management of subfoveal choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD) or pathological myopia (PM). PDT with verteporfin over 1 and 2 years reduces the decline in visual acuity in patients with classic-containing subfoveal CNV secondary to AMD. Verteporfin is generally well tolerated by most patients. Verteporfin is also effective in patients with CNV secondary to PM, although data in this indication are limited and further controlled studies are required. Although verteporfin has shown efficacy in patients with occult AMD-related subfoveal CNV lesions in early trials, data are currently limited on its first-line use in this indication; fully published data from the Verteporfin In Occult (VIO) trial are therefore awaited with interest. Verteporfin should be considered as a first-line treatment in patients with predominantly classic subfoveal CNV secondary to AMD, and in patients with smaller minimally classic subfoveal CNV lesions. It may also be considered an option for the treatment of patients with occult AMD-related subfoveal CNV in whom visual acuity decreases or predominantly classic features develop over time.

Zinc status and taste acuity in older Europeans: the ZENITH study

Age-related decline in taste acuity may be both a cause and an effect of depleted zinc and/or increased zinc requirement. The aim of this study was to explore associations between zinc status and taste acuity in healthy older European adults aged 55-90 y. Volunteers were recruited within Italy (n = 108 aged 70-90 y), the United Kingdom (UK) (n = 93 aged 55-70) and two regions of France (n = 186), Grenoble (aged 70-90 y) and Clermont-Ferrand (aged 55-70 y). A signal detection theory approach was adopted, employing a three-alternative, forced-choice procedure. The data were converted to R-indices and bivariate correlations were computed to explore relationships between serum zinc, erythrocyte zinc and taste acuity. ANOVA was undertaken to determine regional differences in zinc status. Higher erythrocyte zinc status was associated with better acuity for salt (sodium chloride) taste in the sample as a whole (P = 0.012) (n = 385). Higher serum zinc levels were associated with greater sensitivity to sour taste (citric acid) (P = 0.015) only in the older groups (aged 70-90 y). There were no apparent associations between serum or erythrocyte zinc status and acuity for bitter (quinine) or sweet (sucrose) tastes irrespective of age. These results agree with those previously suggesting that age-related detriment in sensitivity for salt taste may be associated with depleted zinc.

Modified Osteo-odonto-keratoprosthesis for Treatment of Corneal Blindness

To evaluate long-term anatomical and functional outcomes of a modified osteo-odonto-keratoprosthesis (OOKP) technique for treatment of corneal blindness from various etiologies. Two-hundred three patients (224 eyes) underwent modified OOKP surgery between 1973 and 1999. Of the original cohort, 181 patients (98 men and 83 women; mean [SD], age 54.3 [15] years) in whom a standardized 2-step surgical procedure was performed were included in the study. Preoperative diagnoses were dry eye (n = 70) due to ocular pemphigoid (n = 39), Sjögren syndrome (n = 11), trachoma (n = 8), Lyell syndrome (n = 6), Stevens-Johnson syndrome (n = 4), and graft-vs-host disease (n = 1) and congenital lid coloboma (n = 1), severe corneal burns (n = 68), bullous keratopathy (n = 13), keratitis sequelae (n = 15), and bullous keratopathy secondary to antiglaucoma surgery (n = 15). Several innovations were made to the original Strampelli technique. Median follow-up duration was 12 years (range, 1-25 years). Anatomical complications leading to OOKP loss were found in 11 (6.07%) of 181 patients. Survival analysis estimated that 18 years after surgery, the probability of retaining an intact OOKP was 85% (95% confidence interval, 79.3%-90.7%). Pooling patient groups, mean (SD) best postoperative visual acuity was 0.76 (0.34). Mean (SD) final acuity at the end of follow-up declined slightly (0.69 [0.39]) but significantly (P<.01). In individual diagnostic groups, mean acuity decline reached statistical significance (P<.05) only in the pemphigoid (1 line), trachoma (1 line), and bullous keratopathy secondary to antiglaucoma surgery (2 lines) groups. Survival analysis estimated that 18 years after surgery, the probability of retaining best postoperative visual acuity (within 2 lines) was mean (SD) 55.5% (12.9%). Modified OOKP surgery for corneal blindness of different etiologies may provide, in the long-term, anatomically stable corneal prosthesis as well as an effective, rehabilitating recovery in visual acuity.

The Association between Visual Acuity and Central Retinal Thickness in Retinitis Pigmentosa

To determine whether visual acuity is related to central retinal thickness in patients with retinitis pigmentosa. Visual acuities were measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts and optical coherence tomography (OCT3) was used to calculate retinal thicknesses and grade third high-reflectance bands in 162 patients with the typical forms of retinitis pigmentosa who had Snellen visual acuities of 20/20 to 20/200, minimal to no cataracts, and no visible macular cysts. Sixty-five patients were retested within 2 months to estimate the intervisit variability of retinal thickness measurements. ETDRS acuity was best related to retinal thickness measured at fixation and as the average value over the central 1 mm by a second-order polynomial (r(2) = 0.38 and P < 0.001 in both cases). Acuity was maximal for intermediate retinal thickness and appeared to decline for both lesser and greater retinal thicknesses. By linear regression, the decline in acuity for decreasing retinal thickness was steeper in eyes with an absent third high-reflectance band than for eyes with a partially distinct band. No decline was noted in eyes with an intact band. Assessment of intervisit variability of retinal thickness measurements showed 98% confidence limits of +/-17 microm at fixation and +/-11 microm for the central 1 mm. Both retinal thinning (due to cell loss) and retinal thickening (due to presumed edema) appear to be associated with lower visual acuity in patients with typical retinitis pigmentosa. The definition of the OCT third high-reflectance band may help to predict which patients are more likely to lose visual acuity as retinal thickness declines. An increase or decrease in retinal thickness of more than 17 microm at fixation or 11 microm over the central 1 mm at follow-up can be considered a significant (P < 0.01) change in these patients.

ACQUIRED COLOR BLINDNESS IN AN ELDERLY MALE PATIENT FROM RECURRENT METASTATIC PROSTATE CANCER

ACQUIRED COLOR BLINDNESS IN AN ELDERLY MALE PATIENT FROM RECURRENT METASTATIC PROSTATE CANCER

Exploration of the relationship between vitrectomy opportunity and curative effect in proliferative diabetic retinopathy(PDR)

目的 探讨增生性糖尿病性视网膜病变(PDR)的手术时机与疗效的关系.方法我院1998年8月～2003年8月间行玻璃体视网膜手术的增生性糖尿病视网膜病变44例(56眼),分为增生早期组(糖尿病视网膜病变合并玻璃体积血或既往曾作全视网膜光凝治疗)24眼,增生晚期组(广泛血管纤维膜增生合并牵引性视网膜脱离)32眼,进行回顾性分析.结果经过3月～3年随访(平均11.3月),增生早期组24眼均有不同程度的视力改善,0.3者20眼(83.33%),最佳视力达1.0;增生晚期组15眼视力有所提高,最佳视力为0.4,4眼视力下降(其中两眼继发新生血管性青光眼而黑矇).结论正确把握糖尿病PDR玻璃体切除术手术时机,同时玻璃体切除术中行足量有效的眼内光凝,才能提高疗效降低糖尿病眼病的致盲率。

Microdot test of foveal function. A comparison with visual acuity at high and low contrast

To define normal values across age from novel computerized tests of foveal vision and to compare the findings with visual acuity (VA) at high and low contrast. Sixty-one healthy volunteers, aged 22-87, with subjectively normal vision participated in the study. The right eye from each subject was tested with Snellen letter VA at high contrast, at 10% contrast using the Tri-VA test and with the Rarebit Microdot Fovea Test (RMFT), in addition to biomicroscopy and fundus examination. The median letter VA was 0.77 minimum angle of resolution (MAR; range 0.63-1.54) with a significant decline in letter VA with increasing age (r = 0.7, p < 0.001). The median Tri-VA resolution threshold at 10% contrast was 1.8 MAR (range 0.9-4.1) and a significant age effect (r = 0.7) was observed, most pronounced above 65 years. The median RMFT hit rate was 100% (range 97-100) in the age group below 65 years and 87.5% (range 34-98) in subjects older than 65 years. The study shows a decline in foveal function with age with all three methods, reflecting the loss of neural detectors with increasing age. The hit rate to microdot stimuli appears to be a sensitive measure, which can be used for fine-graded evaluation of foveal function.

Vision and Self-Rated Health: Longitudinal Findings from an Older Australian Population

Purpose: To assess temporal associations between vision and self-rated health. Methods: We examined 3654 Australian residents (82.4% response) aged 49+ years in the Blue Mountains Eye Study, during 1992 to 1994, and re-examined 2334 in 1997 to 1999. Change in vision was defined if baseline and 5-year visual acuity (VA) changed by ≥10 letters (2 lines). Change in self-rated health was defined if overall health ranking (excellent, good, fair, poor) changed by ≥1 step. Results: Of 2285 participants with data from both examinations, 59.8%, 23.9%, and 16.3% reported unchanged, declined, and improved self-rated health, respectively. Among persons whose self-rated health declined, the proportions with a decline in presenting VA, no change, or improvement were similar (25.2%, 23.8% and 22.5%, respectively, p for trend = 0.5). Among participants with decline, no change, or improvement in self-rated health, a similar magnitude in the age-sex adjusted mean VA decline (−1.0 to −2.7 letters) was observed. After adjusting for age, sex, hospitalizations, and incident chronic conditions, declining VA was not associated with increased decline in 5-year self-rated health (multivariate-adjusted odds ratio 0.99, 95% CI 0.75–1.30). Conclusion: There were no parallel 5-year changes in self-rated health and vision in this population.

Neuromyélite optique de Devic et hépatite virale A: À propos d’une observation pédiatrique

Devic optic neuromyelitis is a rare clinical disease that involves severe transverse myelitis and unilateral or bilateral optic neuropathy. Its pathogenesis would be explained by demyelinization triggered by bacterial or viral infections phenomena. According to several author, prognosis would be better in children.We report a case of optic neuromyelitis in an 8-year-old child with an uneventful history who was admitted because he suffered from flaccid tetraplegia and sudden decline of the visual acuity. The ophthalmologic examination revealed bilateral neuropapillitis. The medullary MRI visualized a spreading myelitis with bifocal arachnoiditis. Search for a precipitating infectious factor showed positive IgM for viral hepatitis A. With corticosteroid treatment the child achieved total recovery of vision and recovered motor and sensorial function of the upper limbs and the trunk. Paraplegia with sphincteral disorders persisted.This case characterized by the precipitating factor (hepatitis virus A), illustrates this rare syndrome. We present a general review of the pediatric cases reported in the literature.

Choroidal and Skin Metastases from Papillary Thyroid Cancer: Case and a Review of the Literature

A patient with widely metastatic papillary thyroid cancer who had been previously treated with (131)I and external beam radiation presented with purple nodular lesions on his face and scalp. On biopsy, the nodules were papillary carcinoma with cells that stained for thyroglobulin. Subsequently he developed decreased left eye visual acuity, and fundoscopy revealed lesions typical of choroidal metastases. Dermal and choroidal metastases of papillary thyroid carcinoma are both rare. However, the significance of these clinical manifestations may be overlooked and ignored unless the diagnosis is considered. New skin nodules or visual acuity decline in a patient with papillary thyroid cancer may represent manifestations of distant metastatic disease and should prompt thorough evaluation with dermatological examination and fundoscopy. Choroidal and skin metastases have almost always occurred in patients with advanced disease, but initial presentation with these lesions is possible, and in such instances a thorough search for additional sites of metastatic disease is recommended. Occasionally such metastases may respond to (131)I therapy or external beam radiation.

Neuropathie optique métastatique

Ocular metastasis always involves the uveal tractus, especially the choroid. Papillary metastases have been exceptionally described, and represent only 5 percent of the ocular metastatic locations. We report in this observation a case of papillary metastasis in a patient treated for a metastatic adenocarcinoma. A 35-year-old woman was given chemotherapy for four months for metastatic adenocarcinoma involving the pleura and bones. She consulted for significant decline of visual acuity in the left eye associated with headache and vomiting. The fundus examination revealed a yellowish papillary lesion with edema associated with an inferior peripapillary serous retinal detachment. The fluorescein retinal angiography showed a choroidal lesion highly suggestive of choroidal metastasis. Cerebro-orbital CT scan revealed the presence of multiple cerebral metastases. The patient died four months after diagnosis of ocular metastasis and eleven months after diagnosis of adenocarcinoma. Presence of a papillary lesion suggests the possible diagnosis of papillary metastasis despite the lack of a history of neoplasia. Carcinomatosis tumors, especially breast and the lung carcinomas are the most frequent causes of papillary metastasis.

Surgery for hemorrhagic choroidal neovascular lesions of age-related macular degeneration: Ophthalmic findings: SST report no. 13

To present best-corrected visual acuity (BCVA) findings and other clinical outcomes from eyes of patients enrolled in one of the Submacular Surgery Trials (SST) evaluating surgical removal versus observation of predominantly hemorrhagic subfoveal choroidal neovascularization (CNV) associated with age-related macular degeneration. Randomized clinical trial (SST Group B Trial). Eligible patients had subfoveal choroidal neovascular lesions greater than 3.5 disk areas (8.9 mm2) composed of at least 50% blood (either blood or CNV underlying the center of the foveal avascular zone) and BCVA of 20/100 to light perception in the study eye. Patients were assigned randomly at time of enrollment to observation or surgical removal of blood and any associated CNV. A successful outcome was defined a priori as either improvement in visual acuity (VA), no change in VA, or a decline in VA of no more than 1 line (7 letters) from baseline to the 24-month examination based on an intent-to-treat analysis. Of 336 patients enrolled, 168 were assigned to each treatment arm; treatment arms were balanced by baseline characteristics. Of 1501 expected examinations 3 months through 36 months after baseline, 1370 (91%) were performed. Loss of > or =2 lines (> or =8 letters) of VA occurred in 56% of surgery eyes, versus 59% of observation eyes examined at 24 months. Although severe loss of VA was not the primary outcome of interest, surgery more often prevented such loss: 36% in the observation arm versus 21% in the surgery arm at the 24-month examination (chi2 P = 0.004). Of initially phakic eyes, the cumulative percentage that had undergone cataract surgery by 24 months was 44% in the surgery arm, compared with 6% in the observation arm. Twenty-seven eyes (16%) in the surgical arm, compared with 3 eyes (2%) in the observation arm, had a rhegmatogenous retinal detachment (RD). Submacular surgery as performed in the SST Group B Trial did not increase the chance of stable or improved VA (the primary outcome of interest) and was associated with a high risk of rhegmatogenous RD, but did reduce the risk of severe VA loss in comparison with observation. This article contains additional online-only material available at http://www.ophsource.com/periodicals/ophtha.

Diagnosis and treatment of orbital optic nerve sheath meningioma.

Primary and secondary optic nerve sheath meningiomas (ONSMs) are neoplasms that account for a large proportion of optic nerve and orbital tumors. The diagnosis is not always straightforward and is based on the appropriate clinical findings and neuroimaging. Biopsy or surgical intervention may occasionally be necessary but is associated with significant morbidity. Issues related to clinical signs and symptoms, diagnosis, natural history, and treatment strategies are reviewed based on a review of published literature. Diagnosis is usually based on radiographic and clinical findings. Biopsies are not obtained in most cases, thus adding further to the bias of possible misdiagnosis in all reported case series that do not have the benefit of histopathologic confirmation. Natural history typically shows inexorable progression in most cases, although long periods of stability are occasionally reported. Treatment options include observation, radiation alone, surgery alone, and combined radiation and surgery. The optimum timing of interventional therapy and radiation are evolving. After serial examination documents new decline in acuity and/or visual field, fractionated radiotherapy appears most likely to preserve visual function and is a valid treatment approach for primary orbital ONSM. Tumor enlargement, as determined by serial imaging, may also provide an indication to begin radiotherapy.

Intravitreal Triamcinolone Acetonide: Valuation of Retinal Thickness Changes Measured by Optical Coherence Tomography in Diffuse Diabetic Macular Edema

The authors studied the efficacy of intravitreal triamcinolone acetonide in a case series of patients with diffuse diabetic macular edema without evidence of vitreous-macular traction refractory to laser photocoagulation. Six eyes with clinically diffuse diabetic macular edema that failed to respond to at least two previous sessions of laser photocoagulation were included. The mean age of selected patients was 72.5+/-13.8 years, with a preoperative best-corrected visual acuity reduced to 1.48+/-0.18 logMar and a mean baseline intraocular pressure (IOP) of 15.17+/-2.64 mmHg. The authors also studied macular thickness measured by optical coherence tomography (OCT 2000 scanner, Humphrey Instruments, San Leandro, CA) - in the preoperative period it was 640.8+/-171.1 microm - and the fluorangiographic (Heidelberg Retina Angiograph, Heidelberg Engineering GmbH, Heidelberg, Germany) patterns, which showed pooling in tardy phases and leakage. Mean follow-up was 4 months. In each patient the authors observed a significant improvement, both functionally and anatomically. Mean best-corrected visual acuity increased in the postoperative period to 0.94+/-0.53 logMar. No patient showed decline of visual acuity at the end of follow-up. Base line macular thickness was reduced in the postoperative period to 312.2+/-157.65 microm measured by OCT and fluorangiographic patterns showed a reduction of pooling and of leakage. The most common complications described in the literature were not observed and the increase of mean IOP in the postoperative period to 18.76+/-5.72 mmHg was not significant. Intravitreal triamcinolone acetonide may decrease macular edema and improve visual acuity in eyes with diffuse diabetic macular edema.

Higher risk of multiple falls among elderly women who lose visual acuity

Objective To determine the association between changes in visual acuity (VA) and frequent falls in older women. Design Prospective cohort study. Participants Two thousand two elderly community-residing women participating in the Study of Osteoporotic Fractures with measurements of VA at baseline and a follow-up examination 4 to 6 years later (mean of 5.6 years). Methods Binocular VA with habitual correction was measured under standard illumination using Bailey–Lovie charts at baseline and fourth examinations. Change in VA was stratified into 5 categories: no change or VA gain, loss of 1 to 5 letters, loss of 6 to 10 letters, loss of 11 to 15 letters, and loss of >15 letters. A separate analysis considered decline in VA as the loss of ≥10 letters (≥2 lines) on the Bailey–Lovie acuity measure between baseline and follow-up examinations. Main outcome measures Data on falls were obtained from postcards sent every 4 months after the follow-up examination. Frequent falling was defined as ≥2 falls during a 1-year period after the follow-up examination. Results Compared with women with stable or improved VA, women with declining acuity had significantly greater odds of experiencing frequent falling during the subsequent year. Odds ratios after adjustment for baseline acuity and other confounders were 2.08 (95% confidence interval [CI]: 1.39–3.12) for loss of 1 to 5 letters, 1.85 (95% CI: 1.16–2.95) for loss of 6 to 10 letters, 2.51 (95% CI: 1.39–4.52) for loss of 11 to 15 letters, and 2.08 (95% CI: 1.01–4.30) for loss of >15 letters. In the analysis of visual decline defined as a loss of ≥10 letters, heightened risk of frequent falling was evident in each of 2 subgroups defined by splitting the sample on baseline VA, with borderline significant evidence of a more pronounced effect in those women with baseline VA of 20/40 or worse ( P value for interaction, 0.083). Conclusions Loss of vision among elderly women increases the risk of frequent falls. Prevention or correction of visual loss may help reduce the number of future falls.

Intravitreal triamcinolone acetonide: valuation of retinal thickness changes measured.

The authors studied the efficacy of intravitreal triamcinolone acetonide in a case series of patients with diffuse diabetic macular edema without evidence of vitreous-macular traction refractory to laser photocoagulation. Six eyes with clinically diffuse diabetic macular edema that failed to respond to at least two previous sessions of laser photocoagulation were included. The mean age of selected patients was 72.5 13.8 years, with a preoperative best-corrected visual acuity reduced to 1.48 0.18 logMar and a mean baseline intraocular pressure (IOP) of 15.17 2.64 mmHg. The authors also studied macular thickness measured by optical coherence tomography (OCT 2000 scanner, Humphrey Instruments, San Leandro, CA) in the preoperative period it was 640.8 171.1 m and the fluorangiographic (Heidelberg Retina Angiograph, Heidelberg Engineering GmbH, Heidelberg, Germany) patterns, which showed pooling in tardy phases and leakage. Mean follow-up was 4 months. In each patient the authors observed a significant improvement, both functionally and anatomically. Mean best-corrected visual acuity increased in the postoperative period to 0.94 0.53 logMar. No patient showed decline of visual acuity at the end of follow-up. Base line macular thickness was reduced in the postoperative period to 312.2 157.65 m measured by OCT and fluorangiographic patterns showed a reduction of pooling and of leakage. The most common complications described in the literature were not observed and the increase of mean IOP in the postoperative period to 18.76 5.72 mmHg was not significant. Intravitreal triamcinolone acetonide may decrease macular edema and improve visual acuity in eyes with diffuse diabetic macular edema. (Eur J Ophthalmol 2004; 14: 321-4).

Fingertip skin conformance accounts, in part, for differences in tactile spatial acuity in young subjects, but not for the decline in spatial acuity with aging.

The ability of the skin to conform to the spatial details of a surface or an object is an essential part of our ability to discriminate fine spatial features haptically. In this study, we examined the extent to which differences in tactual acuity between subjects of the same age and between younger and older subjects can be accounted for by differences in the properties of the skin. We did so by measuring skin conformance and tactile spatial acuity in the glabrous skin at the fingertip in 18 younger (19-36 years old) and 9 older (61-69 years old) subjects. Skin conformance was measured as the degree to which the skin invaded the spaces in the psychophysical stimuli. There were several findings. First, skin conformance accounted for 50% of the variance in our measure of tactile spatial acuity (the threshold for grating orientation discrimination) between the younger subjects. The subjects with more compliant skin had substantially lower thresholds than did the subjects with stiffer skin. Second, the skin of the younger subjects was more compliant across than along the skin ridges, and this translated into significantly greater performance when the gratings were oriented along than when oriented across the skin. Third, skin conformance was virtually identical in the younger and the older subjects. Consequently, skin conformance cannot account for the loss of spatial acuity reported in earlier studies and confirmed in this study. We infer that the loss must be neural in origin.

Decline of tactile acuity in aging: a study of body site, blood flow, and lifetime habits of smoking and physical activity

Tactile acuity of 60 older subjects (≥ 65 years) and 19 younger subjects (18–28 years) was assessed by two-point gap thresholds at the upper and lower surfaces of the forefinger, at the upper and lower surfaces of the feet, and at the volar surface of the forearm. The older subjects were assigned to one of four groups of 15 subjects each, depending on reported lifetime habits of physical activity and smoking: (1) active smokers, (2) active nonsmokers, (3) inactive smokers, and (4) inactive nonsmokers. Peripheral blood flow was assessed at the forefinger, foot, and forearm by means of laser-Doppler imaging and skin temperature recordings, under resting conditions and during and after a 5-min exposure to mild cooling (28°C). Consistent with previous studies, tactile acuity thresholds in the foot and finger averaged about 80% higher in the older subjects than in the younger subjects, but only about 22% higher in the forearm. Although the upper surface of the fingertip was more sensitive than the lower surface in both younger and older subjects, the age-related decline in tactile acuity was nearly identical on both sides of the finger and foot. The latter finding refutes the hypothesis that the larger effect of aging in the extremities results from greater physical wear and tear on the contact surfaces of the hands and feet. Self-reported lifetime histories of physical activity and smoking were not significantly associated with measures of cutaneous blood flow or tactile thresholds. Possible reasons for this lack of association are discussed, including the inherent limitations of testing only healthy older subjects, and the concept of “successful aging”.