The purpose of this study was to determine the characteristics of fonts that contribute to the legibility and readability of small print for adult readers of different age. Specifically, this investigation sought to: 1) determine the degree to which the legibility and readability of small print varies as a function of observer age, font, and font type (serif versus sans serif), 2) evaluate font usability on a number of subjective dimensions (e.g., preference, ease of use), and 3) assess the relationship between readability, legibility and spatial measures of vision for different fonts and font types for observers of different age.
Aging is associated with a gradual decline in visual functioning sufficient to affect performance on most everyday visual tasks. Much of this deficit is attributable to changes in the ocular media of the eyes, the balance to sensorineural changes in the retina and brain (Kline & Scialfa, 1996).
Ocular media: A reduction in pupil size (senile miosis), in conjunction with increased opacity in the ocular media, gradually reduces the amount of light reaching the older retina. It has been estimated that the 60-year-old retina receives only one-third as much light as its 20-year old counterpart (Weale, 1961). Most of this reduction is attributable to pupillary miosis and the increased opacity of the lens. In addition to the attenuation in retinal illuminance, light is increasingly scattered by the aging eye (Ijspeert, de Waard, van den Berg & de Jong, 1990), reducing contrast in the retinal image independent of refractive state and pupil size (Artal, Ferro, Miranda & Navarro, 1993). In addition to its increased opacity, the lens becomes thicker and sclerotic, reducing its accommodative power (i.e., presbyopia) causing a recession in the visual near point (the nearest distance at which the eye can focus). The associated yellowing of the lens causes a selective absorption of short wavelength light (i.e., blues and greens).
Retina: There is a 30% decrease in rod density in the central area of the retina, but apparently little loss of foveal cones (Curcio, Millican, Allen & Kalina, 1993). There is some evidence from ERG studies for an age-related decline in functioning of both rods and cones (Elsner, Berk, Burns & Rosenberg, 1988). There also appears to be a decline in the number (e.g., Gao & Hollyfield, 1992) and function of retinal ganglion cells (e.g., Celesia, Kaufman & Cone, 1987; Porciatti, Burr, Morrone & Fiorentini, 1992).
Eye movements: There is an age-related decrement in saccadic latency (Huaman & Sharpe, 1993; Sharpe & Zackon, 1987; Whitaker, Shoptaugh & Haywood, 1986), as well as reductions in peak saccadic velocity (Pitt & Rawles, 1988) and accuracy (Huaman & Sharpe, 1993). Older adults, however, do not appear to lose the ability to maintain gaze while observing stationary stimuli, at least up to durations of 13 seconds (Kosnik, Kline, Fikre & Sekuler, 1987).
Visual pathways: The degree of senescent loss in the two major visual pathways is still unclear. There is some indication that loss of functioning in the parvocellular (sustained) pathway exceeds that in the magnocellular (transient) pathway (Spear, 1993; Elliott, Whitaker & MacVeigh, 1990).
Visual cortex: Studies suggest relatively little decline in neuronal density of striate cortex (e.g., Vincent, Peters & Tigges, 1989). Vincent et al. (1989), however, found some evidence of dendritic degradation.
Resolution acuity: Resolution acuity, the ability to see small detail in stationary targets, typically of high contrast, decreases progressively with age. Where most young observers are able to detect a target gap subtending 1 minute of arc (minarc) of visual angle (VA), the 70 year old has a near acuity of 1.5 minarc (Pits, 1982). In the Snellen acuity notation these correspond to 6/6 and 6/9 acuity respectively (the numerator in the Snellen fraction refers to the test distance in meters and the denominator refers to the distance at which a normal person with "good" vision could resolve a target of the same size). Examples of a common acuity-type tasks include reading of words or numbers on a distant billboard or license plate. Such acuity deficits can be seen by age 30 in uncorrected vision, and in corrected vision by age 70 (Gittings & Fozard, 1986). Due to the age-related decline in retinal illumination, age-related acuity effects are exacerbated in low light (Sturr, Kline & Taub, 1990).
Severe or debilitating acuity loss is also strongly age-related. About 46% of those who are legally blind (corrected acuity of 6/60 or less and/or a visual field of 20 degrees or smaller), and approximately 68% of those with severe visual impairment (unable to read newspaper print at 40 cm with their best correction) are over the age of 65 (Kirchner & Lowman, 1988). Branch, Horowitz and Carr (1989) reported that visual impairment is the second most prevalent physical impairment among people over 65, and is perceived as more disabling than most other physical impairments.
Dynamic visual acuity (DVA): The ability to resolve detail in a moving target, known as dynamic visual acuity (DVA) declines with age (Scialfa et al., 1988), especially at high target velocities.
Contrast sensitivity: Contrast sensitivity (CS), the minimum light/dark differences that can be detected for targets of varied size (i.e., spatial frequency), shows progressive age loss for targets of intermediate and high spatial frequency (Elliott, 1987). This age loss is further exacerbate by stimulus motion (Scialfa, Garvey, Tyrrell & Leibowitz, 1992). Consistent with their general need for higher illumination levels, the CS Function of older observers is affected adversely by low light conditions (Sloane, Owsley & Alvarez, 1988). Neural factors also appear to contribute to this loss (Kline & Scialfa, 1996).
Glare susceptibility: Although more light is required for the older person to see well, the level, direction and distribution of the light becomes increasingly important (Kline & Scialfa, 1997). Due to changes in the ocular medium, the senescent eye is more susceptible to the effects of glare and also takes longer to recover from it (Elliott & Whitaker, 1990).
Aging, visual search and visual fields: Older people experience a visual deficit while searching for targets in complex stimulus arrays (conspicuity) as well as suffer from shrinking useful fields of view (Scialfa, Kline & Lyman, 1987). Older adults do not appear to suffer from a loss of vigilance (Monk, Buysse, Reynolds, Jarrett and Kupfer, 1992) under good viewing conditions, but an age-related deficit can be seen under degraded conditions (Parasuraman & Giambra, 1992; Parasuraman, Nestor & Greenwood, 1989). Older people are also more likely to be distracted by irrelevant stimulus (Rabbitt, 1965; Scialfa & Esau, 1993; Sekuler & Ball, 1986)
Aging eye problems and reading: Given their lack of accommodative ability, and the recession of the nearest point they can focus (presbyopia), older readers cannot compensate for small print by moving it closer to their eyes. Also important is the fact that less light is reaching the sentient eye (senile miosis), making print more difficult to see. Not only is the overall luminance of the stimulus reduced, but so is its contrast. All of these factors make it more difficult to read stimuli, particularly under conditions of low light and small print.
Aging and self-reported visual problems. Even in the absence of visual pathology, many elderly people report increased difficulty on visual tasks including searching for objects, tracking moving text, near vision (reading), vision in low light and processing rapidly presented information (Kline et al., 1992; Kosnik, Winslow, Kline, Rasinski & Sekuler, 1988; Schieber, 1992; Szlyk, Arditi, Coffey & Laderman, 1990).
Typography refers to features of alphanumeric characters, both individually and as they are positioned in relation to each other in strings, words, and passages. A typeface or font is a distinct design of an alphabet of letters and related characters (Conover, 1990). The ability to create custom fonts on the personal computer has moved font creation and use from the professional printing facility to the desktop environment. Consequently, there has been an "explosion" in font types, and associated with this, markedly increased concern about the effects of various font characteristics on readability and legibility.
Size: Type size is the size of the capital letters and any space added to create space between lines and traditionally has been measured in points (1 point = 1/72 inch). The point size of letters actually refers to the "slug" on which they were set, rather than the letter itself. When considering the actual letter size, a "point" is about 1/100" of an inch (Sanders & McCormick, 1987). A somewhat more realistic way to denote the size of a typeface is by its "x-height" (Barnhurst, 1994; Poulton, 1972), which is the height of a lower case "x" (see Figure 1). Ascenders and descenders refer to the parts of a letter that rise above or fall below the x-height space, respectively.
Case: The "case" of a letter refers to its capitalization. Although upper-case letters are generally more legible (Kember & Varley, 1987) and may (Vartabedian, 1971) or may not (Bednall, 1992) aid in the speed of localizing a word within a list, reviews on designing text (Hartley, 1978; van Nes, 1986) recommend the use of mixed-case print. It is more characteristic, aids in the development of word forms (orthographic images), issubjectively preferred over all capitals (Tinker, 1963), and increases reading speed (Tinker, 1965),
Weight: The weight of a font refers to the relative thickness of the lines that compose the letters. The text on this page is printed in a normal weight print, thicker lines are used in bold print (e.g., Bold). Barnhurst (1994) states that bold print is more legible. Smither and Braun (1994) found that, although bold words are read faster, they result in more errors, and older readers feel that they are more difficult to read. Although Paterson and Tinker (1940) found no advantage to bold print, they reported that 70% of college students preferred normal weight type. Some fonts also have light versions that utilize thinner lines for the characters.
Spacing: Spacing refers to the amount of space allotted to each alphanumeric character (see Figure 1). Monospaced fonts assign uniform spacing to all characters, and are used primarily on typewriters where proportional spacing is not practical. In proportional spacing characters are spaced in relation to the area they occupy, with some letters (e.g., i. l) being allotted less space than others (e.g., m, w). Research has shown that proportional spaced fonts are easier to read (Beldie, Pastoor & Schwarz, 1983; Smither & Braun, 1994). Although Times (a proportional spaced font) was read 4.7% faster than Courier (a monospaced font) for large print size (within the range of letter size that does not affect reading speed), for small print, Courier could be read twice as fast. They also found that the critical print size (the smallest size that does not degrade reading performance) and legibility were larger (not as good) for Times when compared to Courier. Arditi, Knoblauch and Grunwald (1990) also found this size difference when using Times and a monospaced font created from Times. Letters that are crowded in close proximity make reading more difficult (Anstis, 1974; Watannabe, 1994). Up to a point, legibility improves as inter-letter spacing is increased (Berger, 1956). Recommended spacing for maximum legibility and ease of reading is about 25% of the character size and not less than one stroke width (Degani, 1992). While tracking is the term used to describe uniform spacing between letters, kerning is special spacing (more or less) to remove "unsightly" gaps between certain letters (see Figure 2).
Italics: Tilting the letters, Italics, allows more letters on a line of print and is usually restricted to a small portion of a larger passage to provide increased emphasis. Italics are usually restricted because they make reading more difficult (Tinker, 1955).
Leading: Leading, the space between lines of print, is a term derived from the lead plates that were inserted between lines of print to increase inter-line spacing. Leading is recommended to be at least 25 to 33% of the font size (Degani, 1992). Increased leading improves readability at reasonable levels, but in the extreme, detracts from it (Paterson & Tinker, 1947). Solid set print (with no leading, ascenders on one line touch descenders of the previous line) is not recommended (Tinker, 1963).
Line length: Line length is simply the distance from the left to right margin. Lines that are either very long or very short are difficult to read (Tinker, 1963). Lines of between 50 and 60 characters are considered optimal (Morrell & Echt, 1997; Romano, 1984).
Justification: Justification refers to the manner in which letters or words are aligned. While Trollip and Sales (1986) found that full justification, having both the left and right margins lining up by adding whole spaces between words, slowed reading. Campbell, Marchetti and Mewhort (1981) found no difference between non-justified passages and justification by adding whole spaces between words, however, full justification by distributing small spaces proportionally between letters and words improved reading speed. Jubis and Lee (1991) found no effect in reading speed for justification when reading from a video screen.
Contrast: Contrast refers to the maximum difference in the thickness of strokes within a letter (see Figure 1). While providing for variations in style, very thick and thin lines within the same font make print hard to read and reproduce because the thin parts of the letters degrade visually more readily than do the thick parts (Spiekerman & Ginger, 1993). Thus, a font that has uniform lines (little contrast) is more legible than fonts with high contrast.
Contrast polarity: Contrast polarity refers to the alterations of printing dark letters on a light background or light letters on a dark background. Low vision readers with cloudy ocular media performed better with white letters on a dark background (Legge, Rubin, Pelli & Schleske, 1985). The authors suggested that this finding may be related to the resulting reduction in contrast due to increased light scatter by the cloudy ocular media, an effect which would be greater for black-on-white text than white-on-black. Legge, Pelli, Rubin and Schleske (1985), however, found that for readers with no visual pathology, there was no difference between the two contrast polarities.
Counter: The counter of a letter is the white space within the letters (see Figure 1). It is important that there is enough counter within letters so that they do not "fill in" when viewing small print or print viewed from far away.
Font type: Bell (1993) categorizes fonts into 3 general types: serif, sans serif, and "novelty" fonts. Serif fonts have formal strokes (called serifs) on the ends of some letters, while sans serif fonts do not (see Figure 1). Roman type refers to serif fonts, while Gothic type is usually used to refer to sans serif fonts. The remaining category consists of script and other special-use fonts, and are not within the scope of this study.
It has been reported (Roethlein, 1912) that sans serif fonts are superior to serif fonts in terms of the identification of individual letters (legibility). For this reason highway signs and many headlines in newspapers are printed in sans serif fonts. There is, however, no consensus as to the effects of serif fonts on readability. Degani (1992) has suggested that serifs provide a guide for the eyes to follow across a printed page, facilitating horizontal movement. Reynolds (1984) suggests that serifs may contribute to the individuality of letters, thus aiding the recognition of word shapes. However, there are no empirical data to support either of these claims.
Sans serif fonts may be more readable (i.e., the speed and accuracy of reading) than serif fonts for low-vision adults, and partially sighted individuals may prefer them (Shaw, 1969). However, several other studies have reported a superiority for serif fonts (e.g., Nolan, 1959; Prince, 1966) for low vision readers. Romano (1984) recommends serif fonts for the general public and Rosenbloom (1994) recommended serif fonts over sans serif fonts to increase reading speed for older people. The advisability of this, however, is unclear. Although Sorg (1985) showed that Helvetica (a sans serif font) was easier to read than Century Schoolbook (a serif font), Vanderplas and Vanderplas (1980) found just the opposite. Neither Paterson and Tinker (1932), nor Poulton (1965) found a difference between serif and sans serif fonts in readability. Similarly, Smither and Braun (1994) found that for most dimensions (reading speed, errors, subjective ratings) there was no difference. Moriarty and Scheiner (1984) found no difference between serif and sans serif fonts even with minimal inter-letter spacing.
Reading involves a series of saccadic (ballistic) eye movements across the printed page with perception and comprehension of content occurring during the brief interspersed fixations that account for 90% of reading time (Solan, Feldman & Tujak, 1995). The duration and frequency of fixations vary directly with the difficulty of the text being read (Wickens, 1992). During fixations, identification of letters typically occurs in the high acuity central (foveal) region of the retina. The fovea is about one degree across, which allows identification of about 10 letters, depending on the size of the print. In the parafoveal region, within an asymmetrical window of approximately 10 to 14 characters (slightly favoring the right), more global information such as word boundaries are extracted. Information from this region is used to determine the location of the next saccade. Saccades in the opposite direction (right to left) are called regressions and are used to review material already covered.
Reading speed also varies with the purpose of the reading (Wagenaar, Schreuder & Wijlhuizen, 1987). For example, when preparing to answer questions about content, reading is relatively slow compared to scanning for a particular "target" word within a passage. Carver (1990) suggests that there are five basic types of reading process. The scanning process involves lexical access and occurs at about 600 standard words (6 characters each) per minute (SW/min.). The skimming process (the second level) involves lexical access and semantic encoding and occurs at approximately 450 SW/min. Rouding (normal reading) involves those processes involved in lower reading processes, as well as sentence integration, and occurs at about 300 SW/min. The fourth reading process identified by Carver, learning, requires remembering and occurs at approximately 200 SW/min. The final type of reading, memorizing, requires fact rehearsal as well as all the processes used for the other types of reading, and is said to occur at about 138 SW/min.
Bottom-up processes: Reading is based on both bottom-up (stimulus-driven) and top-down (context-driven) processes. Wickens (1992) describes the bottom-up processes as occurring in a hierarchical fashion wherein features are integrated into letters, letters into words, and words into meaningful sentences. With increased reading experience, reading strategies are likely to change, proceeding from recognition of individual letters to letter-groups or whole-words (Reynolds, 1984). Relatedly, familiarity with particular words also affects how they can be read. Familiar words can be perceived automatically from their overall word shape (orthographic image) and do not have to be read letter-by-letter (Crowder & Wagner, 1992).
Top-down processes: Top-down processes in reading refer to additional information from memory and knowledge of language and impacts the reading process. Some top-down processes stem from contextual constraints in language and some from expectancies created by the context in which the information is found. Top-down processes can affect perception at the level of letter or word recognition, to reduce uncertaincy in reading. This can both aid and hinder the reading process dependent on the accuracy of the top-down effects. For example, ambiguity of letters can be reduced by knowledge of permissible letter combinations (Massaro, Taylor, Venezky, Jasterzembski & Lucas, 1980). Massaro, Taylor, Venezky, Jasterzembski and Lucas also state that the same processes also occurs at the level of word recognition based on the content of the sentence and passage. This redundancy of information aids in reading as long as all the information is in agreement, processing can be hindered when it is not. For example, proof reading is much more difficult when the wrong word is used within a sentence or when the incorrect letter does not alter the orthographic shape. Monk and Hulme (1983) for example, found that the ease of proof reading was directly related to the degree to which the orthographic image of words was disturbed. They suggested that information about the shape of words may be extracted either before or at the same time as letter information.
The effectiveness of visual displays can be assessed in a variety of ways, each of which depends on a complex interaction between the observerís tasks, the observerís visual ability, the visual environment and a wide range of display parameters.
Legibility: Legibility, the degree to which the individual elements defining a display (e.g., letters) can be identified, depends largely on bottom-up processes (stimuli being resolved by identification of their component parts) that are a function of target parameters and/or observer spatial vision abilities. Up to some asymptotic level, legibility is enhanced by high luminance and colour contrast, larger targets, increased intra- and inter-target spacing, and high non-glare illuminance conditions (Sanders & McCormick, 1987). Observer visual variables that affect legibility include acuity, contrast sensitivity, glare susceptibility, and colour sensitivity (Owsley & Sloane, 1990).
Given that legibility increases with increases in letter size, it is most commonly indexed in terms of the minimum size of critical target elements needed for target identification (legibility size). Legibility can also be measured in terms of the greatest distance at which a target of a particular size can be identified (i.e., legibility distance). Since variations in size or distance both affect the angular retinal displacement of the image (i.e., visual angle), by and large, these two measures are interchangeable. Legibility has also been evaluated in terms of the minimum exposure time required for correct identification (i.e., glance legibility).
Readability: Readability is normally concerned with continuous text and refers to the difficulty or ease with which material can be understood. Common measures of readability include reading rate, identification of misspelled words, searching for pre-specified letters, and/or words within word lists or passages. Less frequently used measurements of readability include exposure duration for comprehension, comprehension assessed as a percentage of content questions answered correctly after reading a passage, measurements of eye movements (e.g., number and duration), and reading fatigue.
Readability is affected by some of the same "bottom-up" variables that affect legibility, including luminance, contrast, letter size, and target spacing. However, the relationship between readability and these variables is not always the same as that for legibility. For example, although legibility improves directly with stimulus size, when letters become too large, readability can be adversely affected (Legge, Pelli et al., 1985). Stimuli that exist within a window of parameters have reading speeds independent of their component characteristics. For example, within reasonable limits, print size (Gould & Grischkowsky, 1986), contrast (Legge, Rubin & Luebker, 1987; Timmers, van Nes & Blommaert, 1980), and spatial resolution (Miyao, Hacisalihzade, Allen & Stark, 1989) do not affect the speed at which material is read. It is outside this range or when multiple sub-optimal dimension exists within the same display that readers, particularly older ones, may be disadvantaged. Very little research, however, has systematically examined the relationship between legibility and readability, and none has done so with regard to reader age.
Readability and legibility also differ in the degree to which they are influenced by such top-down factors as redundancy of information, stimulus familiarity, context, reader interests, and complexity of material (Wickens, 1992).
Given their spatial visual deficits and reported difficulties with small print (Vanderplas & Vanderplas, 1980), font characteristics might be expected to be more important determinants of the effectiveness of small print for older readers than younger ones. Consistent with this, Kosnik, et al. (1988) found that older people reported greater difficulty reading small print than did their younger colleagues. Older respondents also reported more difficulty with near visual tasks, and taking longer on reading tasks. These findings were replicated by Kline et al. (1992).
Hartley, Stojack, Mushaney, Annon and Lee (1994), found that there were no age-related reading speed differences when readers were self-paced. Akutsu, Legge, Ross and Schuebel (1991) reported that although older people read as fast as younger people with materials of optimal size, they were more susceptible to deviations in optimum print size. Bouma, Legein, Mélotte and Zabel (1982) found that oral reading speed was invariant with print size for both older and younger readers. Luminance contrast becomes a more important variable for observers with low vision (Rubin & Legge, 1989) such as that found in the elderly. Older people also appear to have more difficulty following a line of text while reading (Szlyk et al., 1990). Reading tasks that are particularly challenging for older people include reading medicine bottles, phone books, price labels and mail (Horowitz, Teresi & Cassels, 1991). Vanderplas and Vanderplas (1980) found that older people are more disadvantaged by small print and low illumination than are younger people.
Print is often inadequate (e.g., small, low contrast) and/or presented under sub-optimal conditions (e.g., low luminance, high glare), even on critical tasks. For example, medicine labels are typically printed in small type, frequently on a colored background, reducing luminance contrast. This makes them difficult to read, particularly for older people in low light conditions (e.g., bathroom at night). Since the elderly are prescribed medications more frequently than any other age groups, low readability of print presents a potential health hazard. Gryfe and Gryfe (1984) for example, report that 84% of elderly medical patents took at least 1 prescription drug. Although people 65 years and older make up 11.6% of the population in Canada (Frideres & Bruce, 1994), they account for 25% of Canadian prescriptions (Gryfe & Gryfe, 1984). Kiernan and Isaacs (1981) found that elderly adults living on their own took, on average, 4.3 medications/person/ day. Park and Jones (1997) indicate that non-adherence is a significant contributor to hospital admissions for older adults. Although this is almost certainly more than a problem of visual perception, it is also the case that if people cannot read the directions and warnings, they cannot comply with the information they provide.
A number of general recommendations have been offered for optimizing print legibility and/or readability. For example, Luckiesh (1937) recommended "...fonts devoid of needless details and with "openness" necessary for good legibility". Barnhurst (1994) recommends "...a simple font, fairly broad, with fairly thick limbs, but not too much contrast between thick and thin lines". Tinker (1963) suggested the use of simplified letter outlines, avoiding long heavy serifs and hair line strokes.
Print that is about two to three times larger than the threshold recognition size is often recommended for optimal readability (Smith, 1984). Once print is sufficiently large to be legible, font characteristics have minimal effects on readability. Thus, when the type is well above threshold size, well illuminated, high in figure-ground contrast, and has adequate letter and line spacing, small differences in print type (e.g., fonts type, font style) are likely to have little impact on readability. Conversely, font characteristics are most likely to affect small print under adverse conditions of low-contrast, poor vision and in poor illumination, such as are frequently encountered when reading medicine bottle labels, telephone books, maps, stamped tool labels, dictionaries, and some newspaper print.
Smith (1979) reported that, given adequate contrast and letter size, other factors influence legibility to a lesser degree. While Sanders and McCormick (1987) agree, they recommend using optimally designed print in certain circumstances (i.e., degraded viewing conditions, critical information being presented, when being read by people with poor vision). Yet Tinker (1965) notes that it is often traditional practices and "the artistic appearance" associated with a font that determines font use in particular applications.
When designing print for older readers, Kline and Lynk (1993) recommend the use of "...clean simple fonts..." (e.g., Helvetica, Chicago, Bookman) and "...avoid ornate ones as they appear cluttered and blurry". While there seems to be some consensus in the recommendation for simple "clean" fonts, the specific advantages and limitations of fonts with and without serifs for older readers has not been determined empirically. This recommendation and those previously mentioned would seem to favor sans serif fonts over serif fonts, especially for readers with impaired spatial vision. Most print, however, including that for those with low-vision, is printed in serif fonts. An exception to this is the newspaper printed by the Canadian National Institute for the Blind, for low vision readers, which is printed in Helvetica (a sans serif font) with 14-point letters.
Considering the critical need of a fast aging population for effective printed materials, this study sought to identify factors that can enhance the effectiveness of print for readers of different ages, especially under sub-optimal viewing conditions. Under sub-optimal conditions (e.g., small print) the characteristics of font type may well be exaggerated for elderly and low vision readers. Designs that appear effective for younger populations in good visual health may not be optimal for elderly readers. The reverse, however, may not be true. For example, Kline and Fuchs (1993) showed that designs optimized for older viewers aided adult observers of all ages.
The following hypotheses were evaluated:
1) Consistent with previous studies, near and far acuity and contrast sensitivity at higher spatial frequencies would be worse for elderly readers.
2) Font legibility, and readability, as assessed by reading time, would be superior for young adult readers compared to elderly readers.
3) Due to the age-related loss in accommodation, the comfortable reading distance of elderly readers would exceed that of young readers.
4) The legibility and readability of sans serif fonts would exceed that of serif fonts for both age groups.
5) The benefits of sans serif fonts over serif fonts for objectively measured reading performance would be greater among older readers (i.e., an age by font type interaction).
6) Subjectively, sans serif fonts would be rated as easier to read, producing less discomfort, having greater clarity, being more simple and preferred, than serif fonts, especially by elderly readers.
7) A significant positive relationship was expected between acuity, high cut-off measure of contrast sensitivity and print legibility.
8) The readability and legibility of fonts would be positively related for both young and elderly readers.
9) Due to contour interaction effects, the legibility and readability would be worse for condensed fonts than non-condensed fonts, especially for elderly readers (i.e., an age by font interaction).