|Year : 1967 | Volume
| Issue : 4 | Page : 135-138
Studies on the depth of the anterior chamber
B Shukla, SP Srivastava
Department of Ophthalmology, G. R. Medical College, Gwalior, India
|Date of Web Publication||21-Jan-2008|
Department of Ophthalmology, G. R. Medical College, Gwalior
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Shukla B, Srivastava S P. Studies on the depth of the anterior chamber. Indian J Ophthalmol 1967;15:135-8
A variety of techniques have been employed by different authors to study depth of the anterior chamber of the eye. They can be classified into:
1. Direct measurements:-Donders (1872), Ulbrich (1914), Schneider (1956), Krannig (1956).
2. Optical Methods:- von Bahr (1945), Maurice and Giardini (1951), Stenstrom (1953), Tornquist (1953), Syndacker (1956).
3. Photographic Methods:- Heim (1941), Goldmann (1941).
4. Ultrasonography:- Janson (1963).
The results obtained by these workers vary from 2.76 to 3.97 mm of depth. Having determined the depth of the anterior chamber, various authors have studied its correlation with age, sex and refractive errors. Our study includes all these studies and also the correlation with the width of the angle of the chamber, The present study is confined to normal individuals only which included cases with physiological errors of refraction.
| Material and Method|| |
In all 120 cases were studied. The first series of 60 cases consisted of doctors and medical students in whom only the depth of the anterior chamber was studied. The second series of 60 cases were taken at random after routine retinoscopy. In these cases the depth was also recorded when the patient accommodated for an object placed at a distance of 10 cm. Gonioscopy was also done in this series.
To measure the depth, a Carl Zeiss slit-lamp was used which is provided with a calibrated drum for measuring the depth. The patients were instructed to look to an object placed 10 meters away. The slit aperture was fully opened and the beam was directed at an angle of 45° . The magnification was 40 times. Corneal vertex was sharply focussed by the tumbler lever, keeping the scale of the measuring drum at O. After focussing the cornea the drum was gradually moved till the pupillary margin was focussed. The excursion recorded the depth upto a tenth of a mm. Observations in each eye were recorded thrice and the average calculated and recorded. For near, the patient was asked to look at a fixed point 10 cm away while the other eye was closed and the observations were repeated in the same way.
Gonioscopy was then performed by van Beuningen's pyramid gonioscope and a slit-lamp, after instilling a local anesthetic. A moderately narrow slit beam was directed at an angle of 30° and a magnification of x 40 was used. Only the upper and lower angles were studied. The width of the angle of the anterior chamber was graded as recommended by the Committee on Glaucoma of the United States Public Health Services.
Grade O:-Closed - only cornea and iris can be seen.
Grade 1:-Very narrow-In addition, Schwalbe's line with or without a narrow band of trabeculum can be seen,
Grade 2:-Narrow-In addition a broad band of trabeculum with or without scleral spur is visible.
Grade 3:-Open-The scleral spur, with or without a narrow band of ciliary body can be seen in addition.
Grade 4:-Widely open-A broad band of ciliary body is exposed to view along with the structures in the angle already mentioned.
As the average difference between the depth of anterior chambers in males (2.714 in 74) and females (2.658 in 46) comes to an insignificant 0.056 mm, no attempt has been made in the subsequent tables, to subclassify into males and females. It may however be noted that Strenstrom (1946) found also the same difference, 0.056 higher for males, whereas Calmittes (1958) found it higher by as 0.20 mm in males.
| Observations|| |
Observations on depth of the different anterior chambers were recorded in relation to the age, sex, refraction, accommodative effort and the width of the angle and have been tabulated in [Table - 1],[Table - 2],[Table - 3],[Table - 4],[Table - 5].
Note that the average difference is not between the right and left eyes but the difference between the two eyes, which is calculated as a positive difference between the two, irrespective of the higher figure being for the right or left.
| Discussion|| |
The average depth of the anterior chamber in eyes with accommodation relaxed, in 120 subjects with an average age of 29.33 was found to be 2.692 mm. This figure is lower than the one found by occidental workers (2.76 to 3.97 mm) who have used the same method for measuring the depth.
Due to refraction by cornea and aqueous, theoretically the iris must appear anterior than it actually is and so the chamber must appear shallower. This cannot be the cause for the comparative shallowness of Indian anterior chambers, for the previous workers have also employed the same technique. The subjects we had selected were dependable as they were intelligent, cooperative and mostly drawn from students and doctors. One possible reason for the comparative shallowness of Indian anterior chambers could be the greater thickness of the more heavily pigmented iris in Indians.
The average difference in the depth of both eyes is found to be 0.115 mm. but the maximum difference is recorded as 0.47 mm. In most of the cases the difference cannot be explained by anisometropia. Hence we feel justified in coining the term "anisometria" for cases having an unequal depth of the anterior chamber where the difference exceeds 0.13 mm. (average 0.115 + 0.015).
As regards age, there is a definite decrease in depth of the anterior chamber as age advances. This is in conformity with that of other observers, although the results are not quite comparable due to the different age groups in which others have worked. Under the circumstances our own figures for differences in relation to refractive errors, accommodation and anglewidth may not be strictly acceptable, as in series 2, in which these investigations were made, had cases with ages varying from 12 to 60. However, in the case of accommodation where the differences involve changes in the same eye, the results may be considered reliable whereas in the case of refractive errors and in that of the width of the chamber angle the results may be considered only comparable and not absolute.
Even making allowance for the above discrepancy, a significantly higher difference in value for the depth of the anterior chamber in myopes (0.24 mm) was recorded in our studies as compared to that of the emmetropes, whereas the difference in value between hypermetropes and emmetropes which was lower by only 0.08 in hypermetropes cannot be considered significant.
The average difference of 0.414 mm [Table - 4] by which the chamber becomes shallower denotes the forward bulge of the anterior lens capsule during accommodation, which depends on the elasticity of the capsule or the plasticity of the lens and the strength of the ciliary muscle. This must vary with age, but the number of cases in the higher age group were too few to draw a significant conclusion therefrom. The mean difference in this forward bulge between the two eyes was 0.104 mm, the highest being 0.36 mm. With equal nervous energy distributed to the two eyes, this difference introduces an element of sclerosis of the lens and may be indicative of it. It may also indicate a large element of personal error which reduces the significance of any inference in this part of the study.
Lastly, the depth has been correlated with the width of the angle of the anterior chamber [Table - 5]. The width of the angle increases in proportion to an increase in depth of the anterior chamber. With few exceptions this was found to be true in spite of adverse effects of age, sex and refraction. The qualitative estimation of the angle therefore is significantly related to quantitative measurement of the depth, and the depth of the anterior chamber can be taken as a reliable guide of the width of the angle of the anterior chamber.
| Summary|| |
Depth of the anterior chamber has been studied in 120 cases, in 2 series of 60 cases each. In the first series, the average estimation of the depth of the anterior chamber in 1 age group (2030) was determined. In the second series, the same was determined in relation to different age groups, refraction, accommodative power and width of the angle of the chamber. The significance of the results have been discussed.
We are grateful to our chief, Dr. A. H. Firdausi, for his direction in this work.
| References|| |
Calmettes et al. (1958) Arch. Ophthal. (Paris), 18, 513.
Donders (1872) IVth Int. Cong. Ophthal. London, 184.
Goldmann H. (1941) Ophthalmologica, 102, 7.
Heim (1941) Ophthalmologica, 102, 193.
Jansson (1963) Acta Ophth. Supp. 74,
Krannig (1956) Ber. dtsch. Ophthal. Ges, 60, 296.
Maurice & Giardini (1961) British J. Ophthal., 35, 169.
Rosengren. (1922) Acta Ophthal, (Kbh.), 9, 103.
Schneider (1956) Trans. Amer. Ophthal. Soc., 54, 675.
Snydacker (1951) Klin. Mbl., Augenkeilk, 199, 192.
Stenstrom (1953) Acta Ophthal. (Kbh.), 31, 265.
Tornquist (1953) Acta Ophthal, (Kbh.). Suppl. 39.
Ulbrich (1914) Klin. Mbl. Augenheilk, 53, 244.
von Bahr (1948) Acta Ophthal. (Kbh.) 26, 247.
von Helmholtz (1856) Physiol. Optik. Leipzig.
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5]